MedWorm.com provides a medical RSS filtering service. Over 6000 RSS medical sources are combined and output via different filters. This feed contains the latest items from the 'Biomedical Microdevices' source. Tue, 07 Feb 2012 07:42:47 +0100 http://www.medworm.com/index.php?rid=5659035&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22278099%26dopt%3DAbstract Authors: Wu D, Wan M Abstract Methylenediphosphonate (MDP)-conjugated adriamycin liposomes (MDP-LADMs) were prepared using mild dynamic dialysis equilibrium method, and their targeted therapeutic effects against osteosarcomas and metastatic SOSP-M lung nodules were evaluated in vivo. The drug loading and encapsulation efficiency of the MDP-LADMs were measured via high-performance liquid chromatography, and their size and morphology of the MDP-LADMs were determined using transmission electron microscopy and a particle size analyzer, respectively. Cells apoptosis were evaluated by flow cytometry and caspase-3 activity. The targeted therapeutic effects of MDP-LADMs against UMR106 and SOSP-M osteosarcoma cells were evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliu... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5659035 Thu, 26 Jan 2012 05:00:00 +0100 5659035 http://www.medworm.com/index.php?rid=5659036&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22273985%26dopt%3DAbstract We present the first implantable drug delivery system for controlled timing and location of dosing in small animals. Current implantable drug delivery devices do not provide control over these factors nor are they feasible for implantation in research animals as small as mice. Our system utilizes an integrated electrolysis micropump, is refillable, has an inert drug reservoir for broad drug compatibility, and is capable of adjustment to the delivery regimen while implanted. Electrochemical impedance spectroscopy (EIS) was used for characterization of electrodes on glass substrate and a flexible Parylene substrate. Benchtop testing of the electrolysis actuator resulted in flow rates from 1 μL/min to 34 μL/min on glass substrate and up to 6.8 μL/min on Parylene substrate. The fully int... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5659036 Wed, 25 Jan 2012 05:00:00 +0100 5659036 http://www.medworm.com/index.php?rid=5621585&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22252566%26dopt%3DAbstract In this study, we developed a bubble removal system capable of both trapping and discharging air bubbles in a consistent and reliable manner. Combined with PDMS (Polydimethylsiloxane) hydrophilic surface treatment and vacuum filling, a microfluidic perifusion system equipped with the bubble trap was successfully applied for long-term culture of mouse pancreatic islets with no bubble formation and no flow interruption. In addition to demonstrating normal cell viability and islet morphology, post-cultured islets exhibited normal insulin secretion kinetics, intracellular calcium signaling, and changes in mitochondrial potentials in response to glucose challenge. This design could be easily adapted by other microfluidic systems due to its simple design, ease of fabrication, and portability. ... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5621585 Wed, 18 Jan 2012 05:00:00 +0100 5621585 http://www.medworm.com/index.php?rid=5621586&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22245953%26dopt%3DAbstract We present in this paper a microfluidic approach to scaling up cell and protein encapsulations. The microfluidic chip consists of a 3D air supply and multi-nozzle outlet for microcapsule generation. It has one alginate inlet and one compressed air intlet. The outlet has 8 nozzles, each having 380 micrometers inner diameter, which produce hydrogel microspheres ranging from 500 to 700 μm in diameter. These nozzles are concentrically surrounded by air nozzles with 2 mm inner diameter. There are two tubes connected at the top to allow the air to escape as the alginate solution fills up the chamber. A variable flow pump 115 V is used to pump alginate solution and Tygon® tubing is used to connect in-house air supply to the air channel and peristaltic/syringe pump to the alginate chamber. A ... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5621586 Sat, 14 Jan 2012 05:00:00 +0100 5621586 http://www.medworm.com/index.php?rid=5621587&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22231286%26dopt%3DAbstract Authors: Wang X, Takebayashi SI, Bernardin E, Gilbert DM, Chella R, Guan J Abstract We have developed a novel method for genetic characterization of single cells by integrating microfluidic stretching of chromosomal DNA and fiber fluorescence in situ hybridization (FISH). In this method, individually isolated cell nuclei were immobilized in a microchannel. Chromosomal DNA was released from the nuclei and stretched by a pressure-driven flow. We analyzed and optimized flow conditions to generate a millimeter-long band of stretched DNA from each nucleus. Telomere fiber FISH was successfully performed on the stretched chromosomal DNA. Individual telomere fiber FISH signals from single cells could be resolved and their lengths measured, demonstrating the ability of the method to quantif... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5621587 Tue, 10 Jan 2012 05:00:00 +0100 5621587 http://www.medworm.com/index.php?rid=5578192&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22222279%26dopt%3DAbstract Authors: Kwasny D, Vedarethinam I, Shah P, Dimaki M, Silahtaroglu A, Tumer Z, Svendsen WE Abstract Cytogenetic and molecular cytogenetic analyses, which aim to detect chromosome abnormalities, are routinely performed in cytogenetic laboratories all over the world. Traditional cytogenetic studies are performed by analyzing the banding pattern of chromosomes, and are complemented by molecular cytogenetic techniques such as fluorescent in situ hybridization (FISH). To improve FISH application in cytogenetic analysis the issues with long experimental time, high volumes of expensive reagents and requirement for trained technicians need to be addressed. The protocol has recently evolved towards on chip detection of chromosome abnormalities with the development of microsystems for FISH an... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5578192 Fri, 06 Jan 2012 05:00:00 +0100 5578192 http://www.medworm.com/index.php?rid=5578194&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22218821%26dopt%3DAbstract We describe the design, basis for its operation, and the precision engineering in the system and microfluidic chip. From a single calibration, we demonstrate PCR amplification of a 500 bp amplicon from λ-phage DNA in multiple consecutive trials on the same instrument as well as multiple identical instruments. This simple, relatively low-cost plug-and-play design is thus accessible to persons who may not be skilled in assembly and engineering. PMID: 22218821 [PubMed - as supplied by publisher] (Source: Biomedical Microdevices) Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5578194 Thu, 05 Jan 2012 05:00:00 +0100 5578194 http://www.medworm.com/index.php?rid=5578193&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22218822%26dopt%3DAbstract Authors: Hong CC, Lin CC, Hong CL, Chang PH Abstract This paper presents enhanced performance of anesthetic propofol biosensors by modifying molecularly imprinted nanocavities of biosensors. In this work, the relationship between molecularly imprinted nanocavities and performance of molecularly imprinted polymer (MIP) films is investigated. The morphological control of imprinted nanocavities on molecularly imprinted biosensors is done by adjusting polymer composition and polymerization process. The newly developed MIP biosensors are characterized using our developed microfluidic biochips and optical microsystems. Experimental results show that the sizes of molecularly imprinted nanocavities were reduced to 10 to 14 nm from 10 to 25 nm. The roughness of the MIP film surface was re... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5578193 Thu, 05 Jan 2012 05:00:00 +0100 5578193 http://www.medworm.com/index.php?rid=5534693&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22160447%26dopt%3DAbstract We present a complete self-contained system for automated cell culture and experiments with real-time optical read-out. The system offers a high degree of user-friendliness, stability due to simple construction principles and compactness for integration with standard instruments. Furthermore, the self-contained system is highly portable enabling transfer between work stations such as laminar flow benches, incubators and microscopes. Accommodation of 24 individual inlet channels enables the system to perform parallel, programmable and multiconditional assays on a single chip. A modular approach provides system versatility and allows many different chips to be used dependent upon application. We validate the system's performance by demonstrating on-chip passive switching and mixing by perist... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5534693 Tue, 13 Dec 2011 05:00:00 +0100 5534693 http://www.medworm.com/index.php?rid=5534692&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22160484%26dopt%3DAbstract In this study, an alternative approach using polyethylene glycol diacrylate (PEG-DA) for spatially controlled multi-cell type patterning inside a bonded microCCA device is described. We constructed a three-cell type PDMS microCCA following a human physiologically based pharmacokinetic (PBPK) modeling, and applied continuous cell culture medium recirculation within the device as a blood surrogate. A fluorescence microscope based direct pattern writing method was used to form cell/hydrogel microstructures with higher cell viability than the traditional UV lamp based method. The positive effect of mixed molecular weight PDG-DA on hydrogel-encapsulated cell membrane integrity was also studied. This prototype PDMS microCCA device was then tested with Triton X-100 as a model toxicant. The combin... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5534692 Fri, 09 Dec 2011 05:00:00 +0100 5534692 http://www.medworm.com/index.php?rid=5534694&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22147020%26dopt%3DAbstract Authors: Coleman TJ, Thomsen JC, Maass SD, Hsu Y, Nygaard IE, Hitchcock RW Abstract Pelvic floor disorders (PFD) affect one of every four women in the United States. Elevated intra-abdominal pressure (IAP) during daily activity or strenuous physical activity has been identified as a risk factor in the prevalence of PFD. However, the relationship between IAP and physical activity is poorly understood and oftentimes activity restrictions are prescribed by physicians without clinical evidence linking various activities to elevated IAP. There are currently no pressure transducers capable of monitoring IAP non-invasively out of a clinical environment. To overcome this shortcoming, a novel intra-vaginal pressure transducer (IVT) was developed to continuously monitor IAP. Improvements wer... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5534694 Wed, 07 Dec 2011 05:00:00 +0100 5534694 http://www.medworm.com/index.php?rid=5534696&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22143877%26dopt%3DAbstract Authors: Lee G, Park I, Kwon K, Kwon T, Seo J, Chang WJ, Nam H, Cha GS, Choi MH, Yoon DS, Lee SW Abstract The concentration of C-reactive protein (CRP), a classic acute phase plasma protein, increases rapidly in response to tissue infection or inflammation, especially in cases of cardiovascular disease and stroke. Thus, highly sensitive monitoring of the CRP concentration plays a pivotal role in detecting these diseases. Many researchers have studied methods for the detection of CRP concentrations such as optical, mechanical, and electrochemical techniques inside microfluidic devices. While significant progress has been made towards improving the resolution and sensitivity of detection, only a few studies have systematically analyzed the CRP concentration using both numerical and e... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5534696 Tue, 06 Dec 2011 05:00:00 +0100 5534696 http://www.medworm.com/index.php?rid=5534695&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22143878%26dopt%3DAbstract This study uses monoclonal antibodies J591 and J415-antibodies that are highly specific for intact extracellular domains of PSMA on live cells-in microfluidic devices for the capture of LNCaPs, a PSMA-expressing immortalized prostate cancer cell line, over a range of concentrations and shear stresses relevant to immunocapture. Our results show that J591 outperforms J415 and a mix of the two for prostate cancer capture, and that capture performance saturates following incubation with antibody concentrations of 10 micrograms per milliliter. PMID: 22143878 [PubMed - as supplied by publisher] (Source: Biomedical Microdevices) Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5534695 Tue, 06 Dec 2011 05:00:00 +0100 5534695 http://www.medworm.com/index.php?rid=5534699&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22124885%26dopt%3DAbstract Authors: Gan Q, Dai D, Yuan Y, Qian J, Sha S, Shi J, Liu C Abstract Due to the unique physicochemical properties and membrane-permeable capacity, mesoporous silica nanoparticles (MSNs) are considered as an ideal carrier for intracellular delivery. Herein, we endeavored to address the size effect of MSNs on the cellular uptake, endosomal escape and controlled release, the key steps for the intracellular delivery. The well-ordered MSNs in the range from 55-nm to 440-nm with similar pore texture were prepared by modified base-catalyzed sol-gel method. With MC3T3-E1 model cell line, the in vitro results indicated that after 12 h cultivation, MSNs within 55 ~ 440 nm could all be internalized into the cells, and further escaped out of the endosomal compartment. The efficiency of th... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5534699 Tue, 29 Nov 2011 05:00:00 +0100 5534699 http://www.medworm.com/index.php?rid=5534698&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22124886%26dopt%3DAbstract Authors: Yu F, Zhao Y, Gu J, Quigley KL, Chi NC, Tai YC, Hsiai TK Abstract The zebrafish (Danio rerio) is an emerging genetic model for regenerative medicine. In humans, myocardial infarction results in the irreversible loss of cardiomyocytes. However, zebrafish hearts fully regenerate after a 20% ventricular resection, without either scarring or arrhythmias. To study this cardiac regeneration, we developed implantable flexible multi-microelectrode membrane arrays that measure the epicardial electrocardiogram signals of zebrafish in real-time. The microelectrode electrical signals allowed for a high level of both temporal and spatial resolution (~20 μm), and the signal to noise ratio of the epicardial ECG was comparable to that of surface electrode ECG (7.1 dB vs. 7.4 dB, respe... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5534698 Tue, 29 Nov 2011 05:00:00 +0100 5534698 http://www.medworm.com/index.php?rid=5534697&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22124887%26dopt%3DAbstract Authors: Rui YF, Liu JQ, Yang B, Li KY, Yang CS Abstract A novel and simple process was proposed to fabricate a parylene-based platinum-black coated wire microelectrode for orbicularis oculi muscle electrical stimulation. Compared with conventional microelectrodes, wire microelectrodes would enable smaller wounds, increased ease of implantation, and improved cosmesis. Meanwhile, the circumferential electrode sites of this wire microelectrode fabricated by lift-off process would contribute to fully contact with tissue and reduction of electrode-tissue interface impedance. The width and the amount of electrode sites could be decided by the thickness and the amount of sacrificial layer, respectively. The platinum-black coatings were electroplated on electrode sites by applying a curre... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5534697 Tue, 29 Nov 2011 05:00:00 +0100 5534697 http://www.medworm.com/index.php?rid=5534701&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22094823%26dopt%3DAbstract Authors: Moon S, Im S, An J, Park CJ, Kim HG, Park SW, Kim HI, Lee JH Abstract A novel glaucoma drainage device (GDD) using a polymeric micro check valve with no reverse flow is presented for the effective regulation of intraocular pressure (IOP). A significant functional improvement was achieved by reducing the possible incidence of hypotony, as the proposed GDD only drains aqueous humor at a certain cracking pressure or higher. The device consists of three biocompatible polymer layers: a top layer (cover), an intermediate layer (membrane), and a bottom layer (base plate with a cannula). All three layers, made of soft polydimethylsiloxane (PDMS), were bonded together to realize the thin GDDs. The bottom layer was selectively coated with chromium (Cr)/gold (Au) to prevent stiction ... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5534701 Fri, 18 Nov 2011 05:00:00 +0100 5534701 http://www.medworm.com/index.php?rid=5534700&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22094824%26dopt%3DAbstract Authors: Wan W, Yeow JT Abstract This paper describes an integrated microchip system as an efficient and cost-effective solution involving Nanotechnology and Lab-on-a-Chip technology for the rapid detection of bacteria. The system is based on using surface-modified gold nanoparticles for efficient cell lysis followed by microchip PCR without having to remove the nanoparticles from the PCR solution. Poly(quaternary ammonium) modified gold nanoparticles are used to provide a novel and efficient cell lysis method without the need to go through time-consuming, expensive and complicated microfabrication processes as most of current cell lysis methods for Lab-on-a-Chip applications do. It also facilitates the integration of cell lysis and PCR by sharing the same reaction chamber as PCR u... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5534700 Fri, 18 Nov 2011 05:00:00 +0100 5534700 http://www.medworm.com/index.php?rid=5420216&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22076383%26dopt%3DAbstract Authors: Johansson L, Enlund J, Johansson S, Katardjiev I, Yantchev V Abstract A device for acoustic particle manipulation in the 40 MHz range for continuous-flow operation in a 50 μm wide PDMS channel has been evaluated. Unidirectional interdigital transducers on a Y-cut Z-propagation lithium nixobate wafer were used to excite a surface acoustic wave that generated an acoustic standing wave inside the microfluidic channel. It was shown that particle alignment nodes with different inter-node spacing could be obtained, depending on device design and driving frequency. The observed inter-node spacing differed from the standard half-wavelength inter-node spacing generally employed in bulk acoustic transducer excited resonant systems. This effect and the related issue of acoustic no... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5420216 Fri, 11 Nov 2011 05:00:00 +0100 5420216 http://www.medworm.com/index.php?rid=5420217&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22072154%26dopt%3DAbstract Authors: Chuang CH, Huang YW, Wu YT Abstract Cell characterization analysis usually involves a sequence of steps such as culture, separation, trapping, examination and recollection. In general, it is difficult to recover the identified cells and achieve a multi-run examination on a single chip for clinical samples. In the present study, a dielectrophoresis (DEP) micro-device was developed for multi-step manipulations of cells at the single-cell level. The structure of the DEP chip consisted of an indium tin oxide (ITO) top electrode, a flow chamber, a middle electrode on an SU-8 surface, a micro-cavity array of SU-8 and distributed electrodes at the bottom of the micro-cavities. The purpose of the three-layer-electrode design was threefold. First, cells could be trapped into the mi... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5420217 Thu, 10 Nov 2011 05:00:00 +0100 5420217 http://www.medworm.com/index.php?rid=5420219&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22069079%26dopt%3DAbstract We present photopatterned macroporous poly(ethylene glycol) diacrylate hydrogel pillars functionalized with kinase substrates within microchannels for quantifying kinase activity in complex cellular lysates. We determined the effect of using a porogen to induce macroporosity in hydrogel pillars and showed that hydrogel poration enhanced the sensitivity of detecting Bcr-Abl activity in cell lysates by an order of magnitude. Bcr-Abl tyrosine kinase activity in K562 cell lysates could be detected from 0.01 μg/μL of cell lysate, corresponding to approximately 500 cells, using GST-Crkl immobilized in macroporous hydrogels. This device was also capable of quantifying inhibition of Bcr-Abl activity by imatinib mesylate, which demonstrates the potential to predict the biochemical response to dr... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5420219 Wed, 09 Nov 2011 05:00:00 +0100 5420219 http://www.medworm.com/index.php?rid=5420218&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22069080%26dopt%3DAbstract In this study we developed a method for the fabrication of 3D cell culture substrates in a multiwell plate format by microstructuring the bottom of 96-well cell culture plates using an ultrasonic embossing process. The resulting microstructured area consists of cubic microcavities in which adherent multicellular aggregates can be formed. We performed the biological evaluation of the system with the liver-derived human cell-line HepG2 and compared the novel substrate with a commercially available 3D culture system comprising porous alginate sponges. Metabolic activity (alamarBlue® reduction) and induction of four biotransformation enzymes (EROD, ECOD, UGT, SULT) were determined by fluorimetry or HPLC. Our results revealed that HepG2 cells in microstructured plates showed a higher mitochond... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5420218 Wed, 09 Nov 2011 05:00:00 +0100 5420218 http://www.medworm.com/index.php?rid=5420220&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22057945%26dopt%3DAbstract Authors: Hsiao AY, Tung YC, Kuo CH, Mosadegh B, Bedenis R, Pienta KJ, Takayama S Abstract Using stereolithography, 20 different structural variations comprised of millimeter diameter holes surrounded by trenches, plateaus, or micro-ring structures were prepared and tested for their ability to stably hold arrays of microliter sized droplets within the structures over an extended period of time. The micro-ring structures were the most effective in stabilizing droplets against mechanical and chemical perturbations. After confirming the importance of micro-ring structures using rapid prototyping, we developed an injection molding tool for mass production of polystyrene 3D cell culture plates with an array of 384 such micro-ring surrounded through-hole structures. These newly designed a... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5420220 Sat, 05 Nov 2011 04:00:00 +0100 5420220 http://www.medworm.com/index.php?rid=5379714&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22048776%26dopt%3DAbstract Authors: Truckenmüller R, Giselbrecht S, Escalante-Marun M, Groenendijk M, Papenburg B, Rivron N, Unadkat H, Saile V, Subramaniam V, van den Berg A, van Blitterswijk C, Wessling M, de Boer J, Stamatialis D Abstract This paper presents cell culture substrates in the form of microcontainer arrays with overlaid surface topographies, and a technology for their fabrication. The new fabrication technology is based on microscale thermoforming of thin polymer films whose surfaces are topographically prepatterned on a micro- or nanoscale. For microthermoforming, we apply a new process on the basis of temporary back moulding of polymer films and use the novel concept of a perforated-sheet-like mould. Thermal micro- or nanoimprinting is applied for prepatterning. The novel cell container arr... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5379714 Thu, 03 Nov 2011 04:00:00 +0100 5379714 http://www.medworm.com/index.php?rid=5379713&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22048777%26dopt%3DAbstract This study proposes and develops a method for rapidly regeneration of antibody on a resonant micro-cantilever sensor. A nitrilotriacetic acid (NTA) derivative is synthesized with cystine and bromoacetic acid, then added with 2-mercaptoethanol to prepare a mixed self-assembled monolayer (SAM) on Au (111) surface of the cantilever. Ni(2+) ions are thereafter chelated on the mixed SAM to form a breakable and re-linkable chelating-bond layer. Repeatable cycles of antibody immobilization and erasing are experimentally validated with a detectable marker of synthesized biotinylated poly peptides harboring six histidine residues (named as His-Bio). Two distinguished pathogenic microbial, Escherichia. coli O157:H7 and Bacillus Anthracis, are detected with the rapidly regenerated sensor. The E. coli... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5379713 Thu, 03 Nov 2011 04:00:00 +0100 5379713 http://www.medworm.com/index.php?rid=5379715&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22037673%26dopt%3DAbstract Authors: Kósa G, Jakab P, Székely G, Hata N Abstract Capsule endoscopy is a promising technique for diagnosing diseases in the digestive system. Here we design and characterize a miniature swimming mechanism that uses the magnetic fields of the MRI for both propulsion and wireless powering of the capsule. Our method uses both the static and the radio frequency (RF) magnetic fields inherently available in MRI to generate a propulsive force. Our study focuses on the evaluation of the propulsive force for different swimming tails and experimental estimation of the parameters that influence its magnitude. We have found that an approximately 20 mm long, 5 mm wide swimming tail is capable of producing 0.21 mN propulsive force in water when driven by a 20 Hz signal providing 0.85 mW... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5379715 Sat, 29 Oct 2011 04:00:00 +0100 5379715 http://www.medworm.com/index.php?rid=5379716&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22009581%26dopt%3DAbstract Authors: North K, Kubiak EN, Hitchcock RW Abstract Continuous force measurement can provide valuable insight to the efficacy of limb loading regimes during fracture rehabilitation. Currently there is no load monitoring device that is capable of more than 1 h of continuous recording. To enable continuous underfoot load monitoring a piezoresistive pressure sensor was encapsulated in a non-compressible silicone gel. This basic approach to signal transduction was implemented in three continuous underfoot load sensor designs. Design I constrained the gel in a rigid urethane housing. Design II constrained the gel in a silicone elastomer bladder. Design III utilized a hybrid approach by constraining the gel with a rigid upperplate inside of an elastomeric bladder. All three designs were ... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5379716 Wed, 19 Oct 2011 04:00:00 +0100 5379716 http://www.medworm.com/index.php?rid=5379717&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21997499%26dopt%3DAbstract Authors: Zhou MD, Yang C, Liu Z, Cysyk JP, Zheng SY Abstract Continuous flow left ventricular assist devices (LVADs) are commonly used as bridge-to-transplantation or destination therapy for heart failure patients. However, non-optimal pumping speeds can reduce the efficacy of circulatory support or cause dangerous ventricular arrhythmias. Optimal flow control for continuous flow LVADs has not been defined and calls for an implantable pressure sensor integrated with the LVAD for real-time feedback control of pump speed based on ventricular pressure. A MEMS pressure sensor prototype is designed, fabricated and seamlessly integrated with LVAD to enable real-time control, optimize its performance and reduce its risks. The pressure sensing mechanism is based on Fabry-Pérot interferome... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5379717 Fri, 14 Oct 2011 04:00:00 +0100 5379717 http://www.medworm.com/index.php?rid=5312802&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21987002%26dopt%3DAbstract Authors: Carugo D, Capretto L, Willis S, Lewis AL, Grey D, Hill M, Zhang X Abstract A microfluidic based device has been developed for the characterisation of embolisation behaviour with polyvinyl alcohol (PVA) hydrogel beads within a microchannel network with bifurcations which mimic the blood vessel network. Both distal and proximal embolisations were achieved within the PMMA-made microdevice exhibiting comparable embolisation characteristics with those observed in vivo. Results showed that small beads allowed more distal embolisations with a reduced control of the spatial location of occlusion sites. In contrast, large beads generated effective proximal embolisations with an improved reproducibility of embolisation performance. Embolic bead hydrodynamics, partitioning at bifurca... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5312802 Tue, 11 Oct 2011 04:00:00 +0100 5312802 http://www.medworm.com/index.php?rid=5312789&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21987003%26dopt%3DAbstract Authors: Portonovo SA, Schmidt J Abstract Reconstitution of ion channels and transmembrane proteins in planar lipid bilayer membranes allow for their scientific study in highly controlled environments. Recent work with lipid bilayers formed from mechanically joined monolayers has shown their potential for wider technological application, including automation and parallelization. However, bilayer areas are highly sensitive to variations in mechanical position and the bilayers themselves cannot withstand significant perfusion of adjacent solutions. Toward this end, here we describe use of an aperture that masks the monolayer contact area, enabling formation of highly consistent bilayer areas and significantly reducing their variation with changes in relative position of the monolayer... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5312789 Tue, 11 Oct 2011 04:00:00 +0100 5312789 http://www.medworm.com/index.php?rid=5312773&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21987004%26dopt%3DAbstract Authors: Ha D, de Vries WN, John SW, Irazoqui PP, Chappell WJ Abstract This paper presents an ultra-thin and flexible polymer-based capacitive pressure sensor for intraocular pressure (IOP) monitoring in a mouse eye. Due to the size limitation of the anterior chamber in the mouse eye, a volume of approximately 700 × 700 × 150 μm(3) on a small substrate is available for the MEMS capacitive pressure sensor. Moreover, the sensor would ideally be easily injectable into place. Further complicating the sensing is the need to operate the device on the curved surface of the anterior chamber with minimum damage to the eye tissue. Therefore, a thin and flexible substrate is required. We fabricate sensors by exploiting Parylene as a biocompatible structural material in a suitable ... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5312773 Tue, 11 Oct 2011 04:00:00 +0100 5312773 http://www.medworm.com/index.php?rid=5312803&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21984034%26dopt%3DAbstract Authors: Laganà M, Raimondi MT Abstract Perfusion bioreactors are widely used in tissue engineering and pharmaceutical research to provide reliable models of tissue growth under controlled conditions. Destructive assays are not able to follow the evolution of the growing tissue on the same construct, so it is necessary to adopt non-destructive analysis. We have developed a miniaturized, optically accessible bioreactor for interstitial perfusion of 3D cell-seeded scaffolds. The scaffold adopted was optically transparent, with highly defined architecture. Computational fluid dynamics (CFD) analysis was useful to predict the flow behavior in the bioreactor scaffold chamber (that was laminar flow, Re = 0.179, with mean velocity equal to 100 microns/s). Moreover, experimental chara... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5312803 Sat, 08 Oct 2011 04:00:00 +0100 5312803 http://www.medworm.com/index.php?rid=5297356&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21979567%26dopt%3DAbstract We present novel hybrid microfabrication methods for microelectrode arrays that combine microwire assembly, microelectromechanical systems (MEMS) manufacturing techniques and precision tool-based micromachining. This combination enables hybrid microfabrication to produce complex geometries and structures, increase material selection, and improve integration. A 32-channel shank microelectrode array was fabricated to highlight the hybrid microfabrication techniques. The electrode shank was 130 μm at its narrowest, had a 127 μm thickness and had iridium oxide electrode sites that were 25 μm in diameter with 150 μm spacing. Techniques used to fabricate this electrode include microassembly of insulated gold wires into a micromold, micromolding the microelectrode shank, post molding mach... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5297356 Fri, 07 Oct 2011 04:00:00 +0100 5297356 http://www.medworm.com/index.php?rid=5297357&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21976029%26dopt%3DAbstract Authors: Wu J, Kodzius R, Xiao K, Qin J, Wen W Abstract In this paper, we report the construction of a polymerase chain reaction (PCR) device for fast amplification and detection of DNA. This device consists of an interchangeable PCR chamber, a temperature control component as well as an optical detection system. The DNA amplification happens on an interchangeable chip with the volumes as low as 1.25 μl, while the heating and cooling rate was as fast as 12.7°C/second ensuring that the total time needed of only 25 min to complete the 35 cycle PCR amplification. An optimized PCR with two-temperature approach for denaturing and annealing (T(d) and T(a)) of DNA was also formulated with the PCR chip, with which the amplification of male-specific sex determining region Y (SRY) gene m... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5297357 Thu, 06 Oct 2011 04:00:00 +0100 5297357 http://www.medworm.com/index.php?rid=5297358&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21964559%26dopt%3DAbstract Authors: Valassis DT, Dodde RE, Esphuniyani B, Fowlkes JB, Bull JL Abstract Motivated by two-phase microfluidics and by the clinical applications of air embolism and a developmental gas embolotherapy technique, experimental and theoretical models of microbubble transport in pulsatile flow are presented. The one-dimensional time-dependent theoretical model is developed from an unsteady Bernoulli equation that has been modified to include viscous and unsteady effects. Results of both experiments and theory show that roll angle (the angle the plane of the bifurcating network makes with the horizontal) is an important contributor to bubble splitting ratio at each bifurcation within the bifurcating network. When compared to corresponding constant flow, pulsatile flow was shown to produc... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5297358 Sat, 01 Oct 2011 04:00:00 +0100 5297358 http://www.medworm.com/index.php?rid=5280180&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21960035%26dopt%3DAbstract Authors: Celia C, Cilurzo F, Trapasso E, Cosco D, Fresta M, Paolino D Abstract Two vesicular colloidal carriers, ethosomes® and transfersomes® were proposed for the topical delivery of linoleic acid, an active compound used in the therapeutic treatment of hyperpigmentation disorders, i.e. melasma, which is characterized by an increase of the melanin production in the epidermis. Dynamic light scattering was used for the physicochemical characterization of vesicles and mean size, size distribution and zeta potential were evaluated. The stability of formulations was also evaluated using the Turbiscan Lab® Expert based on the analysis of sample transmittance and photon backscattering. Ethosomes® and transfersomes® were prepared using Phospholipon 100 G®, as the lecithin componen... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5280180 Thu, 29 Sep 2011 04:00:00 +0100 5280180 http://www.medworm.com/index.php?rid=5280181&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21952982%26dopt%3DAbstract Authors: Li C, Wu PM, Wu Z, Ahn CH, Ledoux D, Shutter LA, Hartings JA, Narayan RK Abstract The injured brain is vulnerable to increases in temperature after severe head injury. Therefore, accurate and reliable measurement of brain temperature is important to optimize patient outcome. In this work, we have fabricated, optimized and characterized temperature sensors for use with a micromachined smart catheter for multimodal intracranial monitoring. Developed temperature sensors have resistance of 100.79 ± 1.19Ω and sensitivity of 67.95 mV/°C in the operating range from15-50°C, and time constant of 180 ms. Under the optimized excitation current of 500 μA, adequate signal-to-noise ratio was achieved without causing self-heating, and changes in immersion depth did not introd... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5280181 Wed, 28 Sep 2011 04:00:00 +0100 5280181 http://www.medworm.com/index.php?rid=5280182&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21947550%26dopt%3DAbstract Authors: Abaci HE, Devendra R, Smith Q, Gerecht S, Drazer G Abstract The ability to control the oxygen level to which cells are exposed in tissue culture experiments is crucial for many applications. Here, we design, develop and test a microbioreactor (MBR) for long-term cell culture studies with the capability to accurately control and continuously monitor the dissolved oxygen (DO) level in the cell microenvironment. In addition, the DO level can be controlled independently from other cues, such as the viscous shear-stress acting on the cells. We first analyze the transport of oxygen in the proposed device and determine the materials and dimensions that are compatible with uniform oxygen tension and low shear-stress at the cell level. The device is also designed to culture a stati... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5280182 Tue, 27 Sep 2011 04:00:00 +0100 5280182 http://www.medworm.com/index.php?rid=5230875&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21915644%26dopt%3DAbstract Authors: Wu Z, Choudhury K, Griffiths HR, Xu J, Ma X Abstract A novel biosensing system based on a micromachined rectangular silicon membrane is proposed and investigated in this paper. A distributive sensing scheme is designed to monitor the dynamics of the sensing structure. An artificial neural network is used to process the measured data and to identify cell presence and density. Without specifying any particular bio-application, the investigation is mainly concentrated on the performance testing of this kind of biosensor as a general biosensing platform. The biosensing experiments on the microfabricated membranes involve seeding different cell densities onto the sensing surface of membrane, and measuring the corresponding dynamics information of each tested silicon membrane in... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5230875 Wed, 14 Sep 2011 04:00:00 +0100 5230875 http://www.medworm.com/index.php?rid=5230874&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21915645%26dopt%3DAbstract Authors: Xia H, Murray K, Soper S, Feng J Abstract Post-translational modifications (PTM) of proteins play essential roles in cellular physiology and disease. The identification of protein substrates and detection of modification site helps understand PTM-mediated regulation in essential biological pathways and functions in various diseases. However, PTM proteins are typically present only at trace levels, making them difficult to identify in mass spectrometry based proteomics. In this paper, we report a novel and sensitive affinity chromatography on the avidin-functionalized poly(methyl methacrylate) (PMMA) microchip for enrichment of nanogram (ng) amount of PTMs. The chemical modification of poly(methyl methacrylate) (PMMA) surfaces yield avidin-terminated PMMA surfaces after UV ... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5230874 Wed, 14 Sep 2011 04:00:00 +0100 5230874 http://www.medworm.com/index.php?rid=5218985&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21909803%26dopt%3DAbstract Authors: Cooney CG, Sipes D, Thakore N, Holmberg R, Belgrader P Abstract Clinical laboratories are recognizing the importance of implementing sensitive and specific molecular diagnostic tests. However, widespread adoption of these tests requires simplified workflows without requiring expensive supporting instrumentation. To enable microarray-based analysis to meet these requirements, we describe a valveless flow cell for disposable use that supports PCR coupled with microarray hybridization in the same chamber. The flow cell assembly consists simply of double-faced tape, a plastic microarray substrate, an absorbent, and a commercially-available hydrophilic thin film. The simple construction lends itself to low-cost and ease of manufacturing, yet several features reduce the complexi... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5218985 Sat, 10 Sep 2011 04:00:00 +0100 5218985 http://www.medworm.com/index.php?rid=5218988&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21898007%26dopt%3DAbstract Authors: Visvanathan K, Li T, Gianchandani YB Abstract This paper reports the feasibility of biopsy needle tract cauterization and cauterization monitoring using an embedded array of piezoceramic microheaters. Circular heaters of lead zirconate titanate (PZT-5A), with 200 μm diameter and 70-80 μm thickness, are fabricated using a batch mode micro ultrasonic machining process. These are then assembled into cavities in the walls of 20-gauge stainless steel needles and sealed with epoxy. Experiments are performed by inserting the proposed biopsy needle into porcine tissue samples. The needle surface exceeds the minimum target temperature rise of 33°C for either radial or thickness mode vibrations. The corresponding input power levels are 236 mW and 325 mW, respectively. The tis... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5218988 Tue, 06 Sep 2011 04:00:00 +0100 5218988 http://www.medworm.com/index.php?rid=5218987&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21898008%26dopt%3DAbstract Authors: Ikeuchi M, Tane R, Ikuta K Abstract Electrospun nanofibers composed of biodegradable polymers are attractive candidates for cell culture scaffolds in tissue engineering. Their fine-meshed structures, resembling natural extracellular matrices, effectively interact with cell surfaces and promote cell proliferation. The application of electrospinning, however, is limited to two-dimensional (2D) or single tube-like scaffolds, and the fabrication of arbitrary three-dimensional (3D) scaffolds from electrospun nanofibers is still very difficult due to the fibers' continuous and entangled form. To address this issue, in this paper, we describe the use of phase-separation-assisted electrospray and electrostatic focusing to perform continuous direct 3D patterning of nanofibrous micr... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5218987 Tue, 06 Sep 2011 04:00:00 +0100 5218987 http://www.medworm.com/index.php?rid=5218986&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21898009%26dopt%3DAbstract Authors: Tanaka T, Ishikawa T, Numayama-Tsuruta K, Imai Y, Ueno H, Yoshimoto T, Matsuki N, Yamaguchi T Abstract The circulating tumor cell test is used to evaluate the condition of breast cancer patients by counting the number of cancer cells in peripheral blood samples. Although microfluidic systems to detect or separate cells using the inertial migration effect may be applied to this test, the hydrodynamic forces acting on cancer cells in high hematocrit blood flow are incompletely understood. In the present study, we investigated the inertial migration of cancer cells in high hematocrit blood flow in microchannels. The maximum hematocrit used in this study was about 40%. By measuring the cell migration probability, we examined the effects of cell-cell interactions, cell deformab... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5218986 Tue, 06 Sep 2011 04:00:00 +0100 5218986 http://www.medworm.com/index.php?rid=5192954&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21882073%26dopt%3DAbstract Authors: Liu Y, Yu J, Du M, Wang W, Zhang W, Wang Z, Jiang X Abstract This paper describes a vacuum-accelerated microfluidic immunoassay (we abbreviate it as VAMI) by sandwiching a filter membrane between a two-layer chip. A direct assay of IgG demonstrated that VAMI could simultaneously achieve higher sensitivity and require less time compared with conventional microfluidic immunoassays. We further applied VAMI to carry out a 3-step competitive assay (including antigen immobilization, competitive reaction and 2(nd) antibody reaction) for detecting the illegal food additive Sudan Red. A total assay time of 15 min with a limit of detection (LOD) of 1 ng ml(-1) is achieved. PMID: 21882073 [PubMed - as supplied by publisher] (Source: Biomedical Microdevices) Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5192954 Wed, 31 Aug 2011 23:00:00 +0100 5192954 http://www.medworm.com/index.php?rid=5141375&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21850483%26dopt%3DAbstract This study explores a new class of duplex microfluidic device which utilizes a dual perifusion network to simultaneously perform live-cell optical imaging of physiological activities and study insulin release kinetics on two islet populations. This device also incorporates on-chip staggered herringbone mixers (SHMs) to increase mixing efficiency and facilitate the generation of user-defined chemical gradients. Mouse islets are used to simultaneously measure dynamic insulin release, changes in mitochondrial potentials, and calcium influx in response to insulin secretagogues (glucose and tolbutamide), and show a high signal-to-noise ratio and spatiotemporal resolution of all measured parameters for both perifusion chambers. This system has many potential applications for studying β-cell phy... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5141375 Wed, 17 Aug 2011 23:00:00 +0100 5141375 http://www.medworm.com/index.php?rid=5141376&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21833766%26dopt%3DAbstract In this study, electric/electrochemical impedance spectroscopy and cyclic voltammetry were used to study the cellular activities of oral cancer cell line CAL 27, including the kinetics of cell adhesion, spreading, and cell proliferation on interdigitated microelectrodes (IMEs). Impedance spectra of CAL 27 cells on IMEs electrodes were obtained in cell growth medium and in 0.1 M PBS with 50 mM [Fe(CN)(6)](3-/4-) as redox probe. Equivalent circuits were used to model both cases. In cell growth medium, impedance spectra allowed us to analyze the changes in capacitance and resistance due to cell attachment on the IMEs over the entire experiment period. It was found that cell spreading caused the most significant decrease in capacitance component and slight increase in resistance component. I... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5141376 Wed, 10 Aug 2011 23:00:00 +0100 5141376 http://www.medworm.com/index.php?rid=5141378&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21826482%26dopt%3DAbstract Authors: Salm E, Liu YS, Marchwiany D, Morisette D, He Y, Razouk L, Bhunia AK, Bashir R PMID: 21826482 [PubMed - as supplied by publisher] (Source: Biomedical Microdevices) Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5141378 Mon, 08 Aug 2011 23:00:00 +0100 5141378 http://www.medworm.com/index.php?rid=5141377&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21826483%26dopt%3DAbstract Authors: Zubair A, Burbelo PD, Vincent LG, Iadarola MJ, Smith PD, Morgan NY Abstract There is great interest in point-of-care antibody testing for the diagnosis of infectious and autoimmune diseases. As a first step in the development of self-contained and miniaturized devices for highly quantitative antibody detection, we demonstrate the application of Luciferase Immunoprecipitation Systems (LIPS) technology in a microfluidic format. Protein A/G was immobilized on the walls of PDMS-glass microchannels of 500 nL volume. The assay proceeds with the simultaneous introduction of plasma and Renilla luciferase-tagged antigens. Following washing, coelenterazine substrate was added and bound antigen-luciferase measured by chemiluminescence. Total assay time, including rinsing and detecti... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5141377 Mon, 01 Aug 2011 23:00:00 +0100 5141377 http://www.medworm.com/index.php?rid=5103177&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21800145%26dopt%3DAbstract Authors: Iwai K, Tan WH, Ishihara H, Takeuchi S This paper describes a simple reusable device that hydrodynamically traps a large number of beads in an array. Guiding pillars allow us to release the trapped beads by simply reversing the flow direction. The trap and reset operations are extremely simple, robust and highly efficient. We analyzed the path of the beads in a microchannel with pillars to optimize the design of the device. We succeeded in arraying hundreds of 100 μm microbeads, subsequently released them in a few minutes, and demonstrated multiple experiments with a single device. PMID: 21800145 [PubMed - as supplied by publisher] (Source: Biomedical Microdevices) Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5103177 Thu, 28 Jul 2011 23:00:00 +0100 5103177 http://www.medworm.com/index.php?rid=5103176&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21800146%26dopt%3DAbstract This study provides a foundation for further on-chip study of the time-dependent mechanism of EED at the single-cell level. PMID: 21800146 [PubMed - as supplied by publisher] (Source: Biomedical Microdevices) Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5103176 Thu, 28 Jul 2011 23:00:00 +0100 5103176 http://www.medworm.com/index.php?rid=5103175&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21800147%26dopt%3DAbstract Authors: Hattersley SM, Greenman J, Haswell SJ Current in vitro methodologies for the culture and analysis of liver specific responses lack the sophistication of in vivo dynamics. In this work, a microfluidic based experimental methodology has been utilized to reproduce a biomimetic microenvironment in which pseudo in vivo liver tissue studies can be carried out under in vitro conditions. This innovative technique, which exploits the inherent advantages of microfluidic technology, has been utilised to study the viability and functionality of explant liver tissue over four days in the presence of varying concentrations of ethanol. Concentrations of ethanol as low as 20 mM have produced a decrease in WST-1 metabolism, a marker of mitochondrial activity, and an increase lactose dehydroge... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5103175 Thu, 28 Jul 2011 23:00:00 +0100 5103175 http://www.medworm.com/index.php?rid=5103178&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21796389%26dopt%3DAbstract Authors: Berry SM, Strotman LN, Kueck JD, Alarid ET, Beebe DJ The selective isolation of a sub-population of cells from a larger, mixed population is a critical preparatory process to many biomedical assays. Here, we present a new cell isolation platform with a unique set of advantages over existing devices. Our technology, termed Immiscible Filtration Assisted by Surface Tension, exploits physical phenomena associated with the microscale to establish fluidic barriers composed of immiscible liquids. By attaching magnetically-responsive particles to a target cell population via immunocapture, we can selectively transport this population across the immiscible barrier and into a separate aqueous solution. The high interfacial energy associated with the immiscible phase / aqueous phase bou... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5103178 Wed, 27 Jul 2011 23:00:00 +0100 5103178 http://www.medworm.com/index.php?rid=5103179&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21792606%26dopt%3DAbstract Authors: Kim MH, Kim HJ, Kim NN, Yoon HS, Ahn SH Atherosclerosis is a major cardiovascular disease involving accumulations of lipids, white blood cells, and other materials on the inside of artery walls. Since the calcification found in the advanced stage of atherosclerosis dramatically enhances the mechanical properties of the plaque, restoring the original lumen of the artery remains a challenge. High-speed rotational atherectomy, when performed with an ablating grinder to remove the plaque, produces much better results in the treatment of calcified plaque compared to other methods. However, the high-speed rotation of the Rotablator commercial rotational atherectomy device produces microcavitation, which should be avoided because of the serious complications it can cause. This resear... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5103179 Tue, 26 Jul 2011 23:00:00 +0100 5103179 http://www.medworm.com/index.php?rid=5103180&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21789549%26dopt%3DAbstract Authors: Salm E, Liu YS, Marchwiany D, Morisette D, He Y, K Bhunia A, Bashir R Food-borne pathogens and food safety-related outbreaks have come to the forefront over recent years. Estimates on the annual cost of sicknesses, hospitalizations, and deaths run into the billions of dollars. There is a large body of research on detection of food-borne pathogens; however, the widely accepted current systems are limited by costly reagents, lengthy time to completion, and expensive equipment. Our aim is to develop a label-free method for determining a change in DNA concentration after a PCR assay. We first used impedance spectroscopy to characterize the change in concentration of purified DNA in deionized water within a microfluidic biochip. To adequately measure the change in DNA concentration... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5103180 Mon, 25 Jul 2011 23:00:00 +0100 5103180 http://www.medworm.com/index.php?rid=5103181&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21786042%26dopt%3DAbstract Authors: Lovchik RD, Wolf H, Delamarche E Commercially available polydimethylsiloxane (PDMS) elastomers, such as Sylgard 184® are widely used in soft lithography and for microfluidic applications. These PDMS elastomers contain fillers to enhance their mechanical stability. The reinforcing fillers, often sub-micrometer small SiO(2) particles, tend to aggregate, swell with water, and thereby become cognoscible in a way that can strongly interfere with the visualization of micro-scale events taking place next to PDMS structures. As PDMS microfluidics are often used for studying cells and micro-/nanoparticles and for creating/handling nanodroplets, it has become highly desirable to employ a PDMS having high optical quality and that allows microscopy observation without artifacts. Here, we... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5103181 Fri, 22 Jul 2011 23:00:00 +0100 5103181 http://www.medworm.com/index.php?rid=5056130&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21773725%26dopt%3DAbstract Authors: Calvo J, Lavandera JL, Agüeros M, Irache JM The aim was to study the ability of bioadhesive cyclodextrin-poly(anhydride) nanoparticles as carriers for the oral delivery of atovaquone (ATO). In order to increase the loading capacity of ATO by poly(anhydride) nanoparticles, the following oligosaccharides were assayed: 2-hydroxypropyl-β-cyclodextrin (HPCD), 2,6-di-O-methyl-β-cyclodextrin (DCMD), randomly methylated-β-cyclodextrin (RMCD) and sulfobuthyl ether-β-cyclodextrin (SBECD). Nanoparticles were obtained by desolvation after the incubation between the poly(anhydride) with the ATO-cyclodextrin complexes. For the pharmacokinetic studies, ATO formulations were administered orally in rats. Overall, ATO displayed a higher affinity for methylated cyclodextrins than for the ot... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5056130 Tue, 19 Jul 2011 23:00:00 +0100 5056130 http://www.medworm.com/index.php?rid=5056129&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21773726%26dopt%3DAbstract Authors: Suri S, Han LH, Zhang W, Singh A, Chen S, Schmidt CE The field of tissue engineering and regenerative medicine will tremendously benefit from the development of three dimensional scaffolds with defined micro- and macro-architecture that replicate the geometry and chemical composition of native tissues. The current report describes a freeform fabrication technique that permits the development of nerve regeneration scaffolds with precisely engineered architecture that mimics that of native nerve, using the native extracellular matrix component hyaluronic acid (HA). To demonstrate the flexibility of the fabrication system, scaffolds exhibiting different geometries with varying pore shapes, sizes and controlled degradability were fabricated in a layer-by-layer fashion. To promote ... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5056129 Tue, 19 Jul 2011 23:00:00 +0100 5056129 http://www.medworm.com/index.php?rid=5056132&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21769637%26dopt%3DAbstract Authors: Frampton JP, Lai D, Sriram H, Takayama S Laminar and pulsatile flow of aqueous solutions in microfluidic channels can be useful for controlled delivery of cells and molecules. Dispersion effects resulting from diffusion and convective disturbances, however, result in reagent delivery profiles becoming blurred over the length of the channels. This issue is addressed partially by using oil-in-water phase systems. However, there are limitations in terms of the biocompatibility of these systems for adherent cell culture. Here we present a fully biocompatible aqueous two-phase flow system that can be used to pattern cells within simple microfluidic channel designs, as well as to deliver biochemical treatments to cells according to discrete boundaries. We demonstrate that aqueous tw... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5056132 Mon, 18 Jul 2011 23:00:00 +0100 5056132 http://www.medworm.com/index.php?rid=5056131&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21769638%26dopt%3DAbstract Authors: Hsu YH, Lu P, Coleman JL, Tang WC This paper reports on a microfluidic platform to isolate and study avian red blood cells (RBCs) infected to various degrees by the malaria parasite Plasmodium gallinaceum. The experimental findings point to the feasibility of using the morphological changes on the surface of the malaria infected avian RBC (miaRBCs) as biomarkers for diagnosis. A glass substrate with a controlled surface roughness was used as part of a polydimethylsiloxane (PDMS) microfluidic channels. When whole-blood samples were introduced into the channels, the miaRBCs would be preferentially slowed and eventually become immobilized on the roughened surface. The surface lesions and furrow-like structures on the miaRBC surfaces offered a markedly higher probability to intera... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5056131 Mon, 18 Jul 2011 23:00:00 +0100 5056131 http://www.medworm.com/index.php?rid=5056133&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21739185%26dopt%3DAbstract Authors: Kwasny D, Kiilerich-Pedersen K, Moresco J, Dimaki M, Rozlosnik N, Svendsen WE The development of new drug therapies relies on studies of cell transmigration in in vitro systems. Migration has traditionally been studied using two methods, the Boyden chamber and a shear flow chamber assay. Though, commonly applied in cell transmigration studies, they are far from imitating a natural migration process. Here we describe a novel in vitro cell transmigration microfluidic assay, which mimicks physiological shear flow conditions in blood vessels. The device was designed to incorporate the principles of both the Boyden chamber and the shear flow chamber assay, i.e. migration through the membrane under flow conditions. The 3D environment of migrating cells is imitated by injecting cell ... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5056133 Thu, 07 Jul 2011 23:00:00 +0100 5056133 http://www.medworm.com/index.php?rid=5008829&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21728068%26dopt%3DAbstract We present three new microbioreactors, each of which allows cells to be cultured in a perfused microenvironment similar to that found in vivo. Our microbioreactors use new technology that permits integration onto the chip (35 mm × 20 mm) of an electrical sensor, in addition to one or more pumping systems and associated perfusion circuitry. The monitoring of Caco-2 cell cultures using electrical impedance spectroscopy (EIS) has allowed us to measure the effects of cell growth, cellular barrier formation and the presence of chemical compounds and/or toxins. Specifically, we have investigated the ability of the electrical sensor to maintain appropriate sensitivity and precision. Our results show that the sensor was very sensitive not only to the presence or the absence of the cells, bu... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5008829 Mon, 04 Jul 2011 23:00:00 +0100 5008829 http://www.medworm.com/index.php?rid=5008830&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21720851%26dopt%3DAbstract This study reports a low-cost charge-coupled device (CCD)-based fluorescence imaging system for rapid detection of waterborne pathogens by isothermal gene amplification in disposable microchips. Fluorescence imaging capability of this monochromatic CCD camera is evaluated by optimizing the gain, offset, and exposure time. This imaging system is validated for 12 virulence genes of major waterborne pathogens on cyclic olefin polymer (COP) microchips, using SYTO-82 dye and real time fluorescence loop-mediated isothermal amplification referred here as microRT(f)-LAMP. Signal-to-noise ratio (SNR) and threshold time (Tt) of microRT(f)-LAMP assays are compared with those from a commercial real-time polymerase chain reaction (PCR) instrument. Applying a CCD exposure of 5 s to 10(5) starting DNA c... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5008830 Thu, 30 Jun 2011 23:00:00 +0100 5008830 http://www.medworm.com/index.php?rid=5008833&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21710369%26dopt%3DAbstract Authors: Masand SN, Mignone L, Zahn JD, Shreiber DI Cell-laden microfluidic devices have broad potential in various biomedical applications, including tissue engineering and drug discovery. However, multiple difficulties encountered while culturing cells within devices affecting cell viability, proliferation, and behavior has complicated their use. While active perfusion systems have been used to overcome the diffusive limitations associated with nutrient delivery into microchannels to support longer culture times, these systems can result in non-uniform oxygen and nutrient delivery and subject cells to shear stresses, which can affect cell behavior. Additionally, histological analysis of cell cultures within devices is generally laborious and yields inconsistent results due to difficu... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5008833 Tue, 28 Jun 2011 23:00:00 +0100 5008833 http://www.medworm.com/index.php?rid=5008832&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21710370%26dopt%3DAbstract In this study, we describe the development of an approach to measure thermal conductivity of liquids and soft bio-tissues using a proof-of-concept MEMS based thermal probe. By employing a microfabricated closely-packed gold wire to function as the heater and the thermistor, the presented thermal sensor can be used to measure thermal conductivities of fluids and natural soft biomaterials (particularly, the sensor may be directly inserted into soft tissues in living animal/plant bodies or into tissues isolated from the animal/plant bodies), where other more standard approaches cannot be used. Thermal standard materials have been used to calibrate two randomly selected thermal probes at room temperature. Variation between the obtained system calibration constants is less than 10%. By incorpor... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5008832 Mon, 27 Jun 2011 23:00:00 +0100 5008832 http://www.medworm.com/index.php?rid=5008831&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21710371%26dopt%3DAbstract Authors: Liu Y, Markov DA, Wikswo JP, McCawley LJ Morphogenesis is a fundamental process by which new blood vessels are formed during angiogenesis. The ability to control angiogenesis would lead to improvements in tissue engineering constructions; indeed, the study of angiogenesis has numerous clinical applications, for example, in the investigation of metastatic cancer, peripheral and coronary vascular disease, and wound healing. Conventional in vitro organotypic cell culture approaches to these studies are limited primarily by their reliance on microvascular vessel formation through a random process of morphogenesis that lacks the spatial reproducibility and orientation needed for high-throughput drug testing. We have developed a bioreactor system for scaffold-guided tubulogenesis co... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5008831 Mon, 27 Jun 2011 23:00:00 +0100 5008831 http://www.medworm.com/index.php?rid=5008837&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21698381%26dopt%3DAbstract Authors: Pathak P, Zhao H, Gong Z, Nie F, Zhang T, Cui K, Wang Z, Wong ST, Que L Real-time tagless monitoring of cell viability using patch-clamp microchips is reported and validated by using fluorescence imaging techniques for the first time. Specifically, four human breast cancer cell lines (MDA-MB231, MDA-MB231-brain metastatic subline (abbreviated as MB231-BR), MB231-BR over-expressing HER2 gene (MB231-BR-HER2), and MB231-BR-vector control for the HER2 (MB231-BR-vector)) have been used for these studies. Systematic experiments on these cells found that the seal impedance/resistance of cells captured by the micro-pipettes always decreases during the process when the cell loses its viability, and therefore it is a valid indicator of live or dead cells. Systematic experiments also fou... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5008837 Wed, 22 Jun 2011 23:00:00 +0100 5008837 http://www.medworm.com/index.php?rid=5008836&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21698382%26dopt%3DAbstract We describe an integration strategy for arbitrary sensors intended to be used as biosensors in biomedical or bioanalytical applications. For such devices ease of handling (by a potential end user) as well as strict disposable usage are of importance. Firstly we describe a generic array compatible polymer sensor housing with an effective sample volume of 1.55 μl. This housing leaves the sensitive surface of the sensor accessible for the application of biosensing layers even after the embedding. In a second step we show how this sensor housing can be used in combination with a passive disposable microfluidic chip to set up arbitrary 8-fold sensor arrays and how such a system can be complemented with an indirect microfluidic flow injection analysis (FIA) system. This system is designed in a... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5008836 Wed, 22 Jun 2011 23:00:00 +0100 5008836 http://www.medworm.com/index.php?rid=5008835&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21698383%26dopt%3DAbstract Authors: Cha KJ, Kim DS In this paper, we propose a novel portable and disposable pressure pump using a porous polydimethylsiloxane (PDMS) sponge and demonstrate its application to a microfluidic lab-on-a-chip. The porous PDMS sponge was simply fabricated by a sugar leaching technique based on capillary suction of pre-cured PDMS into lumps of sugar, thereby enabling us to achieve the porous PDMS sponge composed of interconnected micropores. To indicate the characteristics of the porous PDMS sponge and pump, we measured the average porosities of them whose values were 0.64 and 0.34, respectively. A stress-strain relationship of the fabricated portable pressure pump represented a linear behavior in the compressive strain range of 0 to 20%. Within this range, a pumping volume of the press... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5008835 Wed, 22 Jun 2011 23:00:00 +0100 5008835 http://www.medworm.com/index.php?rid=5008834&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21698384%26dopt%3DAbstract Authors: He Z, Zhang Q, Wang H, Li Y A capillary microchannel (CM) containing TiO(2)-coated ZnO nanorod arrays was applied as a novel microfluidic device to selectively bind and enrich phosphopeptides. The device was prepared by pumping a TiO(2) sol into a CM containing preformed ZnO nanorod arrays. Different thicknesses of the TiO(2) coating were obtained by controlling the flow duration of TiO(2) sol. The modified CM achieved uninterrupted high-throughput introduction, capture and enrichment of phosphopeptides using continuous-flow operation. The microfluidic device based on the modified CM showed great selectivity, sensitivity and durability for the enrichment of phosphopeptides from tryptic protein digests. These results suggest that microfluidic chips employing this strategy can b... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=5008834 Wed, 22 Jun 2011 23:00:00 +0100 5008834 http://www.medworm.com/index.php?rid=4961257&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21695502%26dopt%3DAbstract Authors: Wu YL, Hsu PY, Hsu CP, Wang CC, Lee LW, Lin JJ A polysilicon wire (PSW) sensor can detect the H(+) ion density (pH value) of the medium coated on its surface, and different cells produce different extracellular acidification and hence different H(+) ion densities. Based on this, we used a PSW sensor in combination with a mold-cast polydimethylsiloxane (PDMS) isolation window to detect the adhesion, apoptosis and extracellular acidification of single normal cells and single cancer cells. Single living human normal cells WI38, MRC5, and BEAS-2B as well as non-small-cell lung cancer (NSCLC) cells A549, H1299, and CH27 were cultivated separately inside the isolation window. The current flowing through the PSW channel was measured. From the PSW channel current change as a function ... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4961257 Tue, 21 Jun 2011 23:00:00 +0100 4961257 http://www.medworm.com/index.php?rid=4961258&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21691814%26dopt%3DAbstract Authors: Zhang C, Wang H, Xing D In the field of continuous-flow PCR, the amplification throughput in a single reaction solution is low and the single-plex PCR is often used. In this work, we reported a flow-based multiplex PCR microfluidic system capable of performing high-throughput and fast DNA amplification for detection of foodborne bacterial pathogens. As a demonstration, the mixture of DNA targets associated with three different foodborne pathogens was included in a single PCR solution. Then, the solution flowed through microchannels incorporated onto three temperature zones in an oscillatory manner. The effect factors of this oscillatory-flow multiplex PCR thermocycling have been demonstrated, including effects of polymerase concentration, cycling times, number of cycles, and D... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4961258 Mon, 20 Jun 2011 23:00:00 +0100 4961258 http://www.medworm.com/index.php?rid=4810292&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21448655%26dopt%3DAbstract Authors: Weng CH, Huang TB, Huang CC, Yeh CS, Lei HY, Lee GB The enzyme-linked immunosorbent assay (ELISA) is widely used in medical diagnostics. In order to reduce the diagnosis time and to lower the consumption of sample/reagents in an ELISA assay, a suction-type, automatic, pneumatically-driven microfluidic chip has been designed and fabricated in this study. The microfluidic chip integrates a multi-functional micro-transport/mixing unit, for transporting metering and mixing of samples and reagents in order to automatically perform the entire ELISA protocol. A new surface modification has been adopted which allows for a high processing capacity. The detection sensitivity for the dengue virus is found to be 10(1) PFU/ml, which is much better than a conventional ELISA assay (10(3) P... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4810292 Thu, 12 May 2011 01:03:12 +0100 4810292 http://www.medworm.com/index.php?rid=4810290&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21455756%26dopt%3DAbstract Authors: Vickers DA, Hincapie M, Hancock WS, Murthy SK Lectins are a group of proteins that bind specifically and reversibly to mono- and oligosaccharide carbohydrate structures that are present on the surfaces of mammalian cells. The use of lectins as capture agents in microfluidic channels was examined with a focus on cells associated with T and B lymphocytic leukemia. In addition to examining the adhesion of Jurkat T and Raji B lymphocytes to a broad panel of lectins, this work also examined the capture of these cells from whole blood. Captured T and B lymphocytes were eluted from the microfluidic devices with a solution of the lectin's inhibiting sugar. The capture and release steps were accomplished in under 1 h. The significance of this work lies within the realm of low-cost cap... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4810290 Thu, 12 May 2011 01:02:57 +0100 4810290 http://www.medworm.com/index.php?rid=4810289&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21461664%26dopt%3DAbstract Authors: Green JV, Sun D, Hafezi-Moghadam A, Lashkari K, Murthy SK Uveitis and primary intraocular lymphoma (PIOL) are diseases associated with the invasion of lymphocytes into various regions of the eye, accompanied by expression of inflammatory cytokines. While these diseases are very different in terms of survivability and treatment options they have similar symptoms that make accurate diagnosis challenging. Furthermore, the diagnostic yield with state-of-the-art techniques for cell and cytokine analysis of vitreous and aqueous humor samples is under 20% due to inadequate sensitivity. This paper describes a simple sandwich immunofluorescence assay (sIFA) microfluidic device that is capable of identifying important analytes in ocular biopsies as a potential alternative to current dia... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4810289 Thu, 12 May 2011 01:02:48 +0100 4810289 http://www.medworm.com/index.php?rid=4810285&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21468631%26dopt%3DAbstract Authors: Wu ZJ, Luo Z, Rastogi A, Stavchansky S, Bowman PD, Ho PS PMID: 21468631 [PubMed - in process] (Source: Biomedical Microdevices) Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4810285 Thu, 12 May 2011 01:02:06 +0100 4810285 http://www.medworm.com/index.php?rid=4810279&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21484446%26dopt%3DAbstract Authors: Peng L, Yang M, Guo SS, Liu W, Zhao XZ Interfacial tension plays an important role in microfluidic emulsification, which is the process of preparing emulsions. A promising method which controls droplet behavior according to the function of the interfacial tension in the process of microfluidic emulsification is reported. The droplet size and generation frequency changed regularly to obtain appropriate concentrations of surfactant. This method could be of great help for setting up the size-controllable droplet generation systems, and ameliorating the emulsification technology. The interfacial tension effect was first analyzed by computational simulation before the real experiment, which significantly improved the efficiency of the whole research process. PMID: 21484446 [Pub... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4810279 Thu, 12 May 2011 01:01:42 +0100 4810279 http://www.medworm.com/index.php?rid=4810273&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21556741%26dopt%3DAbstract Authors: Chen SY, Hung PJ, Lee PJ The ability to culture cells in three dimensional extracellular matrix (3D ECM) has proven to be an important tool for laboratory biology. Here, we demonstrate a microfluidic perfusion array on a 96-well plate format capable of long term 3D ECM culture within biomimetic microchambers. The array consists of 32 independent flow units, each with a 4 μl open-top culture chamber, and 350 μl inlet and outlet wells. Perfusion is generated using gravity and surface tension forces, allowing the array to be operated without any external pumps. MCF-10A mammary epithelial cells cultured in Matrigel in the microfluidic array exhibit acinus morphology over 9 days consistent with previous literature. We further demonstrated the application of the microfluidic ar... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4810273 Mon, 09 May 2011 23:00:00 +0100 4810273 http://www.medworm.com/index.php?rid=4810274&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21547537%26dopt%3DAbstract Authors: Liu Y, Wang W, Hu W, Lu Z, Zhou X, Li CM Flow-through immunoassay is an attractive method for fast, inexpensive and high-throughput protein analyses. However, its practical application is limited by low sensitivity. In this work, a highly sensitive flow-through microarray immunoassay device is developed, in which a poly[glycidyl methacrylate-co-poly(ethylene glycol) methacrylate] (P(GMA-co-PEGMA)) brush as a flexible matrix is uniformly coated on a glass slide through a purge-free surface-initiated atom transfer radical polymerization (SI-ATRP) to immobilize capture proteins for a larger loading capacity and higher bioactivity while allowing easy target access to the brush-attached probes for efficient antibody-antigen (Ab-Ag) bindings. The integrated device is then constructe... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4810274 Thu, 05 May 2011 23:00:00 +0100 4810274 http://www.medworm.com/index.php?rid=4810276&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21494794%26dopt%3DAbstract In this study, we report a microfluidic assay of endothelial cell sprouting and migration into an interpenetrating polymer semi-network HA-Collagen (SIPNs CH) hydrogel as ECM providing an enhanced in vivo mimicking 3D microenvironment to cells. The microfluidic chip could provide a well-controlled gradient of growth factor to cells, whereas the hydrogel could mimic a well-defined 3D microenvironment in vivo. (In addition/Furthermore, the microfluidic chip gives a well-controlled gradient of growth factor to cells) For this reason, three types of hydrogel, composed of semi-interpenetrating networks of collagen and hyaluronic acid were prepared, and firstly we proved the role of the hydrogel in endothelial cell migration. The diffusion property and swelling ratio of the hydrogel were charact... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4810276 Thu, 14 Apr 2011 23:00:00 +0100 4810276 http://www.medworm.com/index.php?rid=4810275&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21494795%26dopt%3DAbstract Authors: Anis Y, Houkal J, Holl M, Johnson R, Meldrum D A pico-liter pump is developed and integrated into a robotic manipulation system that automatically selects and transfers individual living cells of interest to analysis locations. The pump is a displacement type pump comprising one cylindrical chamber connected to a capillary micropipette. The top of the chamber is a thin diaphragm which, when deflected, causes the volume of the fluid-filled cylindrical chamber to change thereby causing fluid in the chamber to flow in and out of the micropipette. This enables aspirating and dispensing individual living cells. The diaphragm is deflected by a piezoelectric actuator that pushes against its center. The pump aspirates and dispenses volumes of fluid between 500 pL and 250 nL at flow ... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4810275 Thu, 14 Apr 2011 23:00:00 +0100 4810275 http://www.medworm.com/index.php?rid=4810278&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21487664%26dopt%3DAbstract We describe a microfluidic model of small airways of the lung that mimics airway architecture, recreates physiologic levels of pulmonary pressures, and allows studying cellular response to repeated liquid plug propagation events. Substantial cellular injury happens due to the propagation of liquid plugs devoid of surfactant. We show that addition of a physiologic concentration of a clinical surfactant, Survanta, to propagating liquid plugs protects the epithelium and significantly reduces cell death. Although the protective role of surfactants has been demonstrated in models of a propagating air finger in liquid-filled airways, this is the first time to study the protective role of surfactants in liquid plugs where fluid mechanical stresses are expected to be higher than in air fingers. Ou... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4810278 Tue, 12 Apr 2011 23:00:00 +0100 4810278 http://www.medworm.com/index.php?rid=4810277&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21487665%26dopt%3DAbstract Authors: Venkatesan BM, Polans J, Comer J, Sridhar S, Wendell D, Aksimentiev A, Bashir R Solid-state nanopore sensors are highly versatile platforms for the rapid, label-free electrical detection and analysis of single molecules, applicable to next generation DNA sequencing. The versatility of this technology allows for both large scale device integration and interfacing with biological systems. Here we report on the development of a hybrid biological solid-state nanopore platform that incorporates a highly mobile lipid bilayer on a single solid-state Al(2)O(3) nanopore sensor, for the potential reconstitution of ion channels and biological nanopores. Such a system seeks to combine the superior electrical, thermal, and mechanical stability of Al(2)O(3) solid-state nanopores with the ch... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4810277 Tue, 12 Apr 2011 23:00:00 +0100 4810277 http://www.medworm.com/index.php?rid=4810282&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21479536%26dopt%3DAbstract In this study, transfection efficiency for human hepatocellular liver carcinoma cells synchronized in cell cycle at G0/G1 phase, which was sorted in size with a microfluidic device based on hydrodynamic filtration, was investigated by using a reverse transfection method. The synchronized cells were recovered at the yield of 80% from the micro-channel, and green fluorescent protein gene encoding plasmid mixed with lipofectoamine was transfected. The transfection efficiency of the cells at G0/G1 phase was 1.8 times higher than non-synchronized cells. The manipulation of cell cycle status could increase transfection efficiency in non-viral system, indicating size-based cell cycle synchronization is a powerful tool as a noninvasive method for bioscience and biotechnology. PMID: 21479536 [P... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4810282 Fri, 08 Apr 2011 23:00:00 +0100 4810282 http://www.medworm.com/index.php?rid=4810281&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21479537%26dopt%3DAbstract Authors: Sen A, Harvey T, Clausen J This paper presents use of a microsystem for extraction, capture and detection of pathogenic bacteria such as E-Coli O157:H7 in soil sample. The assay protocol considers Enzyme-linked Immunosorbent Assay (ELISA), with each bacterium sandwiched between a magnetic bead and a horseradish peroxidase (HRP) enzyme. The system employs three different chips, the soil extraction and mixing chip, retention and reaction chip, and the detection chip. The extractor chip extracts bacterial solution directly from soil sample and mixes with magnetic beads (Dynabeads). The retention chip traps bacteria attached to beads in a microfluidic chamber using a bar magnet. Subsequently, bacteria are bound to HRP which finally reacts with substrate solution to generate a fluo... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4810281 Fri, 08 Apr 2011 23:00:00 +0100 4810281 http://www.medworm.com/index.php?rid=4810280&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21479538%26dopt%3DAbstract Authors: Jothimuthu P, Wilson RA, Herren J, Haynes EN, Heineman WR, Papautsky I This work describes development of a lab-on-a-chip sensor for electrochemical detection of highly electronegative heavy metals such as manganese and zinc by anodic stripping voltammetry. The sensor consists of a three-electrode system, with a bismuth working electrode, a Ag/AgCl reference electrode, and a Au auxiliary electrode. Hydrolysis at the auxiliary electrode is a critical challenge in such electrochemical sensors as its onset severely limits the ability to detect electronegative metals. The bismuth working electrode is used due to its comparable negative detection window and reduced toxicity with respect to a conventional mercury electrode. Through optimization of the sensor layout and the working e... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4810280 Fri, 08 Apr 2011 23:00:00 +0100 4810280 http://www.medworm.com/index.php?rid=4810283&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21475940%26dopt%3DAbstract Authors: Chu M, Shirai T, Takahashi D, Arakawa T, Kudo H, Sano K, Sawada SI, Yano K, Iwasaki Y, Akiyoshi K, Mochizuki M, Mitsubayashi K A soft contact-lens biosensor (SCL-biosensor) for novel non-invasive biomonitoring of tear fluids was fabricated and tested. Wearing a biosensor on eye enabled the in situ monitoring of tear contents. The biosensor has an enzyme immobilized electrode on the surface of a polydimethyl siloxane (PDMS) contact lens. The SCL-biosensor was fabricated using microfabrication techniques for functional polymers (PDMS and 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer). In investigation of in vitro characterization, the SCL-biosensor showed excellent relationship between the output current and glucose concentration from 0.03 to 5.0 mmol·L(-1), with a co... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4810283 Thu, 07 Apr 2011 23:00:00 +0100 4810283 http://www.medworm.com/index.php?rid=4810284&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21472409%26dopt%3DAbstract Authors: Brett ME, Zhao S, Stoia JL, Eddington DT There is a need for a simple method to control fluid flow within microfluidic channels. To meet this need, a simple push pin with a polydimethylsiloxane (PDMS) tip has been integrated into microfluidic networks to be placed within the microchannel to obstruct flow. This new valve design can attain on/off control of fluid flow without an external power source using readily-available, low-cost materials. The valve consists of a 14 gauge (1.6 mm) one inch piece of metal tubing with a PDMS pad at the tip to achieve a fluidic seal when pressed against a microfluidic channel's substrate. The metal tubing or pin is then either manually pushed down to block or pulled up to allow fluid flow. The valve was validated using a pressure transducer a... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4810284 Wed, 06 Apr 2011 23:00:00 +0100 4810284 http://www.medworm.com/index.php?rid=4810286&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21468630%26dopt%3DAbstract Authors: Mansoor H, Zeng H, Chiao M A fiber optic confocal catheter with a micro scanning lens was developed for real-time and non-contact thickness measurement of biological tissue. The catheter has an outer diameter and rigid length of 4.75 mm and 30 mm respectively and is suitable for endoscopic applications. The catheter incorporates a lens actuator that is fabricated using microelectromechanical systems (MEMS) technology. The lens is mounted on a folded flexure made of nickel and is actuated by magnetic field. Thickness measurements are performed by positioning the catheter in front of the tissue and actuating the lens scanner in the out-of-plane direction. A single-mode optical fiber (SMF) is used to deliver a 785 nm laser beam to the tissue and relay back the reflected light ... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4810286 Tue, 05 Apr 2011 23:00:00 +0100 4810286 http://www.medworm.com/index.php?rid=4810288&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21465090%26dopt%3DAbstract This study is focused on screening applications and an automatic cell counting protocol is described and evaluated. Finally, we have tested the device and automatic counting by studying the selective survival and clonal expansion of 721.221 B cells transfected to express HLA Cw6-GFP compared to untransfected 721.221 B cells when grown under antibiotic selection for 3 days. The device and automated analysis protocol make up the foundation for development of several novel cellular imaging assays. PMID: 21465090 [PubMed - as supplied by publisher] (Source: Biomedical Microdevices) Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4810288 Mon, 04 Apr 2011 23:00:00 +0100 4810288 http://www.medworm.com/index.php?rid=4810287&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21465091%26dopt%3DAbstract Authors: Browne AW, Ahn CH This work seeks to extend the utility of microfluidics to conventional blood sampling aperati. Daily medical care of hospitalized patients demands repeated needle punctures or interfacing with a catheter to collect blood samples. Large, research grade systems can autonomously sample blood from laboratory animals; however, a disposable aperatus that can be used to repeatedly sample blood from hospitalized patients does not exist. We have designed, fabricated and demonstrated a 3-layered rigid polymer microfluidic blood sampling device with integrated polymer pinch valves for placement in-line between a patient and a saline infusion system. The blood sampler we designed seeks to mitigate sample cross contamination, reduce risks of microbial contamination associ... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4810287 Mon, 04 Apr 2011 23:00:00 +0100 4810287 http://www.medworm.com/index.php?rid=4810291&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21455755%26dopt%3DAbstract Authors: Saenz Cogollo JF, Tedesco M, Martinoia S, Raiteri R In this paper we present a new experimental set-up which combines the surface characterization capabilities of atomic force microscopy at the sub-micrometer scale with non-invasive electrophysiological measurements obtained by using planar micro-electrode arrays. In order to show the potential of the combined measurements we studied the changes in cell topography and elastic properties of cardiac muscle cells as during the contraction-relaxation cycle. The onset of each beating cycle was precisely identified by the use of the extracellular potential signal, allowing us to combine nanomechanical measurements from multiple cardiomyocyte contractions in order to analyze the time-dependent variation of cell morphology and elastic... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4810291 Thu, 31 Mar 2011 23:00:00 +0100 4810291 http://www.medworm.com/index.php?rid=4810293&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21448654%26dopt%3DAbstract Authors: Cai Z, Zhang T, Di L, Xu DM, Xu DH, Yang DA Poly (propylene fumarate)/(Calcium sulfate/β-tricalcium phosphate) (PPF/(CaSO(4)/β-TCP)) is a kind of biodegradable composite designed for bone tissue engineering. The in vitro degradation behavior of this composite has been investigated in our previous study. The aim of this study was to investigate the effects of PPF molecular weight and CaSO(4)/β-TCP molar ratio on the in vivo degradation of PPF/(CaSO(4)/β-TCP) composite and the bone tissue response to PPF/(CaSO(4)/β-TCP). Total 36 PPF/(CaSO(4)/β-TCP) composite samples were implanted into 15.0 mm segmental defects in tibiae of 18 Japanese rabbits, harvested at 2, 4 and 8 weeks after the operation, and analyzed using radiographic and histological analysis to assess the in v... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4810293 Tue, 29 Mar 2011 23:00:00 +0100 4810293 http://www.medworm.com/index.php?rid=4643515&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21424383%26dopt%3DAbstract Authors: Gao Y, Majumdar D, Jovanovic B, Shaifer C, Lin PC, Zijlstra A, Webb DJ, Li D A versatile microfluidic platform allowing co-culture of multiple cell populations in close proximity with separate control of their microenvironments would be extremely valuable for many biological applications. Here, we report a simple and compact microfluidic platform that has these desirable features and allows for real-time, live-cell imaging of cell-cell interactions. Using a pneumatically/hydraulically controlled poly(dimethylsiloxane) (PDMS) valve barrier, distinct cell types can be cultured in side-by-side microfluidic chambers with their optimum culture media and treated separately without affecting the other cell population. The platform is capable of both two-dimensional and three-dimensio... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4643515 Sat, 19 Mar 2011 00:00:00 +0100 4643515 http://www.medworm.com/index.php?rid=4643516&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21409456%26dopt%3DAbstract We report that vertical equipment configurations are important to further mitigate the effects of cell settling for MDA-MB-468 carcinoma cells. We also report that alginate does not disrupt the specific binding interactions that are the basis of carcinoma cell capture in MCIDs. These results indicate that vertical equipment configurations and the addition of alginates can be used to reduce cell settling in buffer based MCID testing and other applications involving large cells suspended in buffer solution. PMID: 21409456 [PubMed - as supplied by publisher] (Source: Biomedical Microdevices) Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4643516 Wed, 16 Mar 2011 00:00:00 +0100 4643516 http://www.medworm.com/index.php?rid=4582142&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21374067%26dopt%3DAbstract Authors: Grießner M, Hartig D, Christmann A, Pohl C, Schellhase M, Ehrentreich-Förster E During the last decade microarrays have become a powerful analytical tool. Commonly microarrays are produced in a non-contact manner using silicone printheads. However, silicone printheads are expensive and not able to be used as a disposable. Here, we show the development and functional characterization of 8-channel plastic microarray printheads that overcome both disadvantages of their conventional silicone counterparts. A combination of injection-molding and laser processing allows us to produce a high quantity of cheap, customizable and disposable microarray printheads. The use of plastics (e.g., polystyrene) minimizes the need for surface modifications required previously for proper printing... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4582142 Fri, 04 Mar 2011 00:00:00 +0100 4582142 http://www.medworm.com/index.php?rid=4582144&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21369761%26dopt%3DAbstract Authors: Wan W, Yeow JT In this paper, a novel method is proposed and demonstrated to be able to lyse gram-negative (E. coli) bacteria cells for Lab-on-a-Chip applications. The proposed method incorporates using titanium dioxide particles as photocatalysts and a miniaturized UV LED array as an excitation light source to perform cell lysis on microchips. The experimental result demonstrates the feasibility of the proposed prototype device. The working device suggests an inexpensive, easy to be fabricated and effective way for microchip cell lysis. The miniaturized UV LED array and the microchip with a reaction chamber can be easily integrated with other functional components to form a customized whole Lab-on-a-Chip system. PMID: 21369761 [PubMed - as supplied by publisher] (Source: ... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4582144 Thu, 03 Mar 2011 00:00:00 +0100 4582144 http://www.medworm.com/index.php?rid=4582143&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21369762%26dopt%3DAbstract We reported that the device was able to detect as few as 10 colony-forming units (CFU) of E. coli in growth medium. While the main conclusions of the original paper remain sound, the data presented in support of those conclusions contained errors that we detail, discuss and correct here. In short, we misidentified a non-specific product as a specific product of our HDA reaction. We incorrectly called reactions containing the non-specific product (length 70 bp) positive. Further investigation demonstrated that our primer set was faulty and not capable of amplifying the specific product. Here we redesigned primers, sequenced all of the products and reran all of the experiments reported previously to generate a new, verified dataset. PMID: 21369762 [PubMed - as supplied by publisher] (So... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4582143 Thu, 03 Mar 2011 00:00:00 +0100 4582143 http://www.medworm.com/index.php?rid=4582145&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21360044%26dopt%3DAbstract Authors: McCarthy PT, Otto KJ, Rao MP Neural prosthetic interfaces based upon penetrating microelectrode devices have broadened our understanding of the brain and have shown promise for restoring neurological functions lost to disease, stroke, or injury. However, the eventual viability of such devices for use in the treatment of neurological dysfunction may be ultimately constrained by the intrinsic brittleness of silicon, the material most commonly used for manufacture of penetrating microelectrodes. This brittleness creates predisposition for catastrophic fracture, which may adversely affect the reliability and safety of such devices, due to potential for fragmentation within the brain. Herein, we report the development of titanium-based penetrating microelectrodes that seek to addre... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4582145 Tue, 01 Mar 2011 00:00:00 +0100 4582145 http://www.medworm.com/index.php?rid=4528336&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21347824%26dopt%3DAbstract Authors: Wang DY, Wu SC, Lin SP, Hsiao SH, Chung TW, Huang YY We design a microfluidic patterned co-culture system for mouse mesenchymal stem cells (mMSCs) and neural cells to demonstrate the paracrine effects produced by the neural cells in facilitating the transdifferentiation from mMSCs to neuron-like cells. Neural cells and mMSC are orderly patterned in the microfluidic co-culturing system without direct cell contact. This configuration provides us to calculate the percentage of neural marker transdifferentiated by mMSCs easily. We obtain higher transdifferentiated ratio of mMSC in the microfluidic co-culturing system (beta III tubulin: 67%; glial fibrillary acidic protein (GFAP): 86.2%) as compared with the traditional transwell co-culturing system (beta III tubulin: 59.8%; GFAP: ... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4528336 Thu, 24 Feb 2011 00:00:00 +0100 4528336 http://www.medworm.com/index.php?rid=4528335&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21347825%26dopt%3DAbstract "Artificial micro organs"-a microfluidic device for dielectrophoretic assembly of liver sinusoids. Biomed Microdevices. 2011 Feb 24; Authors: Schütte J, Hagmeyer B, Holzner F, Kubon M, Werner S, Freudigmann C, Benz K, Böttger J, Gebhardt R, Becker H, Stelzle M In order to study possible toxic side effects of potential drug compounds in vitro a reliable test system is needed. Predicting liver toxicity presents a major challenge of particular importance as liver cells grown in a cell culture suffer from a rapid loss of their liver specific functions. Therefore we are developing a new microfluidic test system for liver toxicity. This test system is based on an organ-like liver 3D co-culture of hepatocytes and endothelial cells. We devised a microfluidic chip featuring cell cultu... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4528335 Thu, 24 Feb 2011 00:00:00 +0100 4528335 http://www.medworm.com/index.php?rid=4528333&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21347826%26dopt%3DAbstract Authors: Wu ZJ, Luo Z, Rastogia A, Stavchansky S, Bowman PD, Ho PS Fabrication techniques have been developed to produce a perforated polymer microtube as a drug delivery device. The technique consists of first forming a silicon platform with trenches and alignment marks to hold the tubes for subsequent processing. Photolithography and reactive ion etching with an inductively coupled plasma source were used to fabricate micro holes on the surface of polyimide tubes. Several materials have been used to form the etching mask, including titanium film deposited by e-beam evaporation and SiO(2) and SiN(x) films deposited by high-density plasma chemical vapor deposition (HDPCVD). Three equidistant holes of 20 μm in diameter were fabricated on polyimide tubes (I.D. = 125 μm). The perforat... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4528333 Thu, 24 Feb 2011 00:00:00 +0100 4528333 http://www.medworm.com/index.php?rid=4473260&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21301965%26dopt%3DAbstract Authors: Seymour JP, Langhals NB, Anderson DJ, Kipke DR A new parylene-based microfabrication process is presented for neural recording and drug delivery applications. We introduce a large design space for electrode placement and structural flexibility with a six mask process. By using chemical mechanical polishing, electrode sites may be created top-side, back-side, or on the edge of the device having three exposed sides. Added surface area was achieved on the exposed edge through electroplating. Poly(3,4-ethylenedioxythiophene) (PEDOT) modified edge electrodes having an 85-μm(2) footprint resulted in an impedance of 200 kΩ at 1 kHz. Edge electrodes were able to successfully record single unit activity in acute animal studies. A finite element model of planar and edge electrodes ... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4473260 Tue, 08 Feb 2011 00:00:00 +0100 4473260 http://www.medworm.com/index.php?rid=4473261&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21286818%26dopt%3DAbstract Authors: Li P, Sherry AJ, Cortes JA, Anagnostopoulos C, Faghri M In this article, a rapid, sensitive, and disposable microfluidic immunosensor is presented for point-of-care (POC) testing and clinical diagnosis. For the first time, the blocking process is eliminated from a microfluidic heterogeneous immunoassay by using protein A functionalized polydimethylsiloxane microchannels. The nonspecific binding of the assay is maintained around the chip background level by using a pair of antibodies with different affinity to protein A under optimized experimental conditions. C-reactive protein (CRP), a biomarker for inflammation and cardiovascular disease risk assessment, is selected as a model analyte to demonstrate the sensitivity of this blocking-free microfluidic heterogeneous immunoassay... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4473261 Tue, 01 Feb 2011 00:00:00 +0100 4473261 http://www.medworm.com/index.php?rid=4473263&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21279444%26dopt%3DAbstract Authors: Parichehreh V, Estrada R, Kumar SS, Bhavanam KK, Raj V, Raj A, Sethu P Blood is a valuable tissue containing cellular populations rich in information regarding the immediate immune and inflammatory status of the body. Blood leukocytes or white blood cells (WBCs) provide an ideal sample to monitor systemic changes and understand molecular signaling mechanisms in disease processes. Blood samples need to be processed to deplete contaminating erythrocytes or red blood cells (RBCs) and sorted into different WBC sub-populations prior to analysis. This is typically accomplished using immuno-affinity protocols which result in undesirable activation. An alternative is size based sorting which by itself is unsuitable for WBCs sorting due to size overlap between different sub-populations... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4473263 Sat, 29 Jan 2011 00:00:00 +0100 4473263 http://www.medworm.com/index.php?rid=4473262&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21279445%26dopt%3DAbstract Authors: Chen L, Conlisk AT One of the recent applications of nanopores is to use them as detectors/analyzers for bio-molecules and nanopore based sequencing has been studied to quickly sequence DNA. In this paper, three categories of forces proposed in the literature to oppose the electrical driving forces in the DNA translocation process are analyzed, (1) the entropic forces of DNA uncoiling/recoiling at the pore entrance/exits, (2) the viscous drag acting on the blob like DNA outside the nanopore, and (3) the viscous drag acting on the linear DNA inside the nanopore. The magnitudes of these forces are calculated based on the parameters used in experiments and it is shown that the first two of the aforementioned categories of forces are usually small compared to the electrical drivin... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4473262 Sat, 29 Jan 2011 00:00:00 +0100 4473262 http://www.medworm.com/index.php?rid=4473264&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21271358%26dopt%3DAbstract Authors: Peham JR, Grienauer W, Steiner H, Heer R, Vellekoop MJ, Nöhammer C, Wiesinger-Mayr H In this article we present a long target droplet polymerase chain reaction (PCR) microsystem for the amplification of the 16S ribosomal RNA gene. It is used for detecting Gram-positive and Gram-negative pathogens at high-throughput and is optimised for downstream species identification. The miniaturised device consists of three heating plates for denaturation, annealing and extension arranged to form a triangular prism. Around this prism a fluoropolymeric tubing is coiled, which represents the reactor. The source DNA was thermally isolated from bacterial cells without any purification, which proved the robustness of the system. Long target sequences up to 1.3 kbp from Staphylococcus aureus, E... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4473264 Thu, 27 Jan 2011 00:00:00 +0100 4473264 http://www.medworm.com/index.php?rid=4407097&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21243437%26dopt%3DAbstract Authors: Wu E, Menon V, Geddie W, Sun Y Laser scanning cytometry (LSC) is emerging as a clinical tool. In one application a "Clatch" slide, named after the inventor, is used in conjunction with LSC for cell surface marker immunophenotyping of patient samples. The slide requires time consuming and laborious pipetting steps, making a test tedious and prone to handling errors. The Clatch slide also uses a significant number of cells, limiting the number of analyses on paucicellular samples. This paper presents an automated microfluidic system consisting of a control circuit, a microfluidic system, and an aluminum frame, capable of performing immunophenotyping procedures. This prototype system reduces 36 pipetting steps to 1, reduces the amount of cell sample from 180 μL to 56 μL, and ... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4407097 Tue, 18 Jan 2011 00:00:00 +0100 4407097 http://www.medworm.com/index.php?rid=4407098&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21240559%26dopt%3DAbstract Authors: McClain MA, Clements IP, Shafer RH, Bellamkonda RV, Laplaca MC, Allen MG Bio-electrodes have traditionally been made of materials such as metal and silicon that are much stiffer than the tissue from which they record or stimulate. This difference in mechanical compliance can cause incomplete or ineffective contact with the tissue. The electrode stiffness has also been hypothesized to cause chronic low-grade injury and scar-tissue encapsulation, reducing stimulation and recording efficiency. As an initial step to resolve these issues with electrode performance, we have developed and characterized electrically-functional, low-Young's modulus, microcable-shaped neuroelectrodes and demonstrated electrophysiological recording functionality. The microcable geometry gives the electro... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4407098 Sat, 15 Jan 2011 00:00:00 +0100 4407098 http://www.medworm.com/index.php?rid=4407099&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21234690%26dopt%3DAbstract This study reports a microfluidic cell culture chip consisting of 48 microbioreactors for high-throughput perfusion 3-dimensional (3-D) cell culture-based assays. Its advantages include the capability for multiplexed and backflow-free medium delivery, and both efficient and high-throughput micro-scale, 3-D cell culture construct loading. In this work, the microfluidic cell culture chip is fabricated using two major processes, specifically, a computer-numerical-controlled (CNC) mold machining process and a polydimethylsiloxane (PDMS) replication process. The chip is composed of micropumps, microbioreactors, connecting microchannels and a cell/agarose scaffold loading mechanism. The performance of the new pneumatic micropumps and the cell/agarose scaffold loading mechanism has been experimen... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4407099 Fri, 14 Jan 2011 00:00:00 +0100 4407099 http://www.medworm.com/index.php?rid=4343160&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21222164%26dopt%3DAbstract Authors: Kwapiszewski R, Skolimowski M, Ziółkowska K, Jędrych E, Chudy M, Dybko A, Brzózka Z An integrated microfluidic system that coupled lysis of two cell lines: L929 fibroblasts and A549 epithelial cells, with fluorescence-based enzyme assay was developed to determine β-glucocerebrosidase activity. The microdevice fabricated in poly(dimethylsiloxane) consists of three main parts: a chemical cell lysis zone based on the sheath flow geometry, a micromeander and an optical fibers detection zone. Unlike many methods described in literature that are designed to analyse intracellular components, the presented system enables to perform enzyme assays just after cell lysis process. It reduces the effect of proteases released in lysis process on determined enzymes. Glucocerebrosidase a... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4343160 Tue, 11 Jan 2011 00:00:00 +0100 4343160 http://www.medworm.com/index.php?rid=4343163&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21207149%26dopt%3DAbstract We present a hybrid chip of polymer and stainless steel designed for high-throughput continuous electroporation of cells in suspension. The chip is constructed with two parallel stainless steel mesh electrodes oriented perpendicular to the liquid flow. The relatively high hydrodynamic resistance of the micrometer sized holes in the meshes compared to the main channel enforces an almost homogeneous flow velocity between the meshes. Thereby, very uniform electroporation of the cells can be accomplished. Successful electroporation of 20 million human dendritic cells with mRNA is demonstrated. The performance of the chip is similar to that of the traditional electroporation cuvette, but without an upper limit on the number of cells to be electroporated. The device is constructed with two femal... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4343163 Wed, 05 Jan 2011 00:00:00 +0100 4343163 http://www.medworm.com/index.php?rid=4343166&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21203849%26dopt%3DAbstract Authors: Reddy B, Dorvel BR, Go J, Nair PR, Elibol OH, Credo GM, Daniels JS, Chow EK, Su X, Varma M, Alam MA, Bashir R Over the last decade, field-effect transistors (FETs) with nanoscale dimensions have emerged as possible label-free biological and chemical sensors capable of highly sensitive detection of various entities and processes. While significant progress has been made towards improving their sensitivity, much is yet to be explored in the study of various critical parameters, such as the choice of a sensing dielectric, the choice of applied front and back gate biases, the design of the device dimensions, and many others. In this work, we present a process to fabricate nanowire and nanoplate FETs with Al(2)O(3) gate dielectrics and we compare these devices with FETs with SiO(2)... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4343166 Tue, 04 Jan 2011 00:00:00 +0100 4343166 http://www.medworm.com/index.php?rid=4343169&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21190086%26dopt%3DAbstract We present a maskless micropatterning system that utilizes a fluorescence microscope with programmable X-Y stage and dry film photoresist to realize feature sizes in the sub-millimeter range (40-700 μm). The method allows for flexible in-house maskless photolithography without a dedicated microfabrication facility and is well-suited for rapid prototyping of microfluidic channels, scaffold templates for protein/cell patterning or optically-guided cell encapsulation for biomedical applications. PMID: 21190086 [PubMed - as supplied by publisher] (Source: Biomedical Microdevices) Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4343169 Wed, 29 Dec 2010 00:00:00 +0100 4343169 http://www.medworm.com/index.php?rid=4278099&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21170592%26dopt%3DAbstract Authors: Bian C, Tong J, Sun J, Zhang H, Xue Q, Xia S A field effect transistor (FET)-based immunosensor was developed for diabetes monitoring by detecting the concentrations of glycated hemoglobin (HbA1c) and hemoglobin (Hb). This immunosensor consists of a FET-based sensor chip and a disposable extended-gate electrode chip. The sensor chip was fabricated by standard CMOS process and was integrated with signal readout circuit. The disposable electrode chip, fabricated on polyester plastic board by Micro-Electro-Mechanical-Systems (MEMS) technique, was integrated with electrodes array and micro reaction pool. Biomolecules were immobilized on the electrode based on self-assembled monolayer and gold nanoparticles. Experimental results showed that the immunosensor achieved a linear respon... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4278099 Sat, 18 Dec 2010 00:00:00 +0100 4278099 http://www.medworm.com/index.php?rid=4278102&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21165700%26dopt%3DAbstract Authors: van Pelt S, Derks R, Matteucci M, Hansen MF, Dietzel A A new concept for the manipulation of superparamagnetic beads inside a microfluidic chip is presented in this paper. The concept allows for bead actuation orthogonal to the flow direction inside a microchannel. Basic manipulation functionalities were studied by means of finite element simulations and results were oval-shaped steady state oscillations with bead velocities up to 500 μm/s. The width of the trajectory could be controlled by prescribing external field rotation. Successful verification experiments were performed on a prototype chip fabricated with excimer laser ablation in polycarbonate and electroforming of nickel flux-guides. Bead velocities up to 450 μm/s were measured in a 75 μm wide channel. By prescr... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4278102 Fri, 17 Dec 2010 00:00:00 +0100 4278102 http://www.medworm.com/index.php?rid=4278105&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21161600%26dopt%3DAbstract Authors: Rahimi S, Sarraf EH, Wong GK, Takahata K This paper reports a micromachined drug delivery device that is wirelessly operated using radiofrequency magnetic fields for implant applications. The controlled release from the drug reservoir of the device is achieved with the microvalves of poly(N-isopropylacrylamide) thermoresponsive hydrogel that are actuated with a wireless resonant heater, which is activated only when the field frequency is tuned to the resonant frequency of the heater circuit. The device is constructed by bonding a 1-mm-thick polyimide component with the reservoir cavity to the heater circuit that uses a planar coil with the size of 5-10 mm fabricated on polyimide film, making all the outer surfaces to be polyimide. The release holes created in a reservoir wall... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4278105 Tue, 14 Dec 2010 00:00:00 +0100 4278105 http://www.medworm.com/index.php?rid=4220720&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21120698%26dopt%3DAbstract Authors: Bartalena G, Grieder R, Sharma RI, Zambelli T, Muff R, Snedeker JG Various micro-devices have been used to assess single cell mechanical properties. Here, we designed and implemented a novel, mechanically actuated, two dimensional cell culture system that enables a measure of cell stiffness based on quantitative functional imaging of cell-substrate interaction. Based on parametric finite element design analysis, we fabricated a soft (5 kPa) polydimethylsiloxane (PDMS) cell substrate coated with collagen-I and fluorescent micro-beads, thus providing a favorable terrain for cell adhesion and for substrate deformation quantification, respectively. We employed a real-time tracking system that analyzes high magnification images of living cells under stretch, and compensates for gr... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4220720 Wed, 01 Dec 2010 00:00:00 +0100 4220720 http://www.medworm.com/index.php?rid=4220725&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21113663%26dopt%3DAbstract Authors: Jeon JS, Chung S, Kamm RD, Charest JL Clinically relevant studies of cell function in vitro require a physiologically-representative microenvironment possessing aspects such as a 3D extracellular matrix (ECM) and controlled biochemical and biophysical parameters. A polydimethylsiloxane (PDMS) microfluidic system with a 3D collagen gel has previously served for analysis of factors inducing different responses of cells in a 3D microenvironment under controlled biochemical and biophysical parameters. In the present study, applying the known commercially-viable manufacturing methods to a cyclic olefin copolymer (COC) material resulted in a microfluidic device with enhanced 3D gel capabilities, controlled surface properties, and improved potential to serve high-volume applications.... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4220725 Sat, 27 Nov 2010 00:00:00 +0100 4220725 http://www.medworm.com/index.php?rid=4220723&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21113664%26dopt%3DAbstract Authors: Kniazeva T, Hsiao JC, Charest JL, Borenstein JT One of the principal challenges in artificial lung technology has been the ability to provide levels of oxygen and carbon dioxide exchange that rival those of the natural human lung, while mitigating the deleterious interaction between blood and the surface of the synthetic gas exchange membrane. This interaction is exacerbated by the large oxygenator surface area required to achieve sufficient levels of gas transfer. In an effort to address this challenge, microfluidics-based artificial lung technologies comprising stacked microchannel networks have been explored by several groups. Here we report the design, fabrication and initial testing of a parallel plate multilayered silicone-based microfluidic construct containing ultrathi... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4220723 Sat, 27 Nov 2010 00:00:00 +0100 4220723 http://www.medworm.com/index.php?rid=4220721&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21113665%26dopt%3DAbstract We describe a simple procedure to characterize a magnetic field sensor based on microelectromechanical systems (MEMS) technology, which exploits the Lorentz force principle. This sensor is designed to detect, in future applications, the spiking activity of neurons or muscle cells. This procedure is based on the well-known capability that a magnetic MEMS device can be used to sense a small magnetic flux density. In this work, an electronic neuron (FitzHugh-Nagumo) is used to generate controlled spike-like magnetic fields. We show that the magnetic flux density generated by the hardware of this neuron can be detected with a new MEMS magnetic field sensor. This microdevice has a compact resonant structure (700 × 600 × 5 μm) integrated by an array of silicon beams and p-type piezor... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4220721 Sat, 27 Nov 2010 00:00:00 +0100 4220721 http://www.medworm.com/index.php?rid=4202013&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21104321%26dopt%3DAbstract Authors: Yang L, Guiseppi-Wilson A, Guiseppi-Elie A Microlithographically fabricated interdigitated microsensor electrodes (IMEs) were cleaned, surface activated, chemically functionalized (amine) and derivatized with an Acrloyl-PEG-NHS to receive a spun-applied monomer cocktail of UV polymerizable monomer. IMEs were 2050.5, 1550.5, 1050.5 and 0550.5 possessing lines and spaces that were 20, 15, 10, and 5 μm respectively; 5 mm line lengths and were 50 lines on each opposing bus. Bioactive hydrogels were synthesized from spun-applied and UV-crosslinked tetraethyleneglycol diacrylate (TEGDA) (crosslinker), 2-hydroxyethylmethacrylate (HEMA), polyethyleneglycol(200) monomethacrylate (PEGMA), N-[tris(hydroxymethyl)methyl]-acrylamide (HMMA) and poly(HEMA) (MW 60,000) (viscosity modifier) ... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4202013 Tue, 23 Nov 2010 00:00:00 +0100 4202013 http://www.medworm.com/index.php?rid=4168130&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21072595%26dopt%3DAbstract We present numerical modeling and experimental studies of flow optimization inside a batch microfluidic micro-reactor used for synthesis of human-scale doses of Positron Emission Tomography (PET) tracers. Novel techniques are used for mixing within, and eluting liquid out of, the coin-shaped reaction chamber. Numerical solutions of the general incompressible Navier Stokes equations along with time-dependent elution scalar field equation for the three dimensional coin-shaped geometry were obtained and validated using fluorescence imaging analysis techniques. Utilizing the approach presented in this work, we were able to identify optimized geometrical and operational conditions for the micro-reactor in the absence of radioactive material commonly used in PET related tracer production platfor... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4168130 Fri, 12 Nov 2010 00:00:00 +0100 4168130 http://www.medworm.com/index.php?rid=4168131&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21063783%26dopt%3DAbstract We present the development of a three-dimensional (3-D) combinatorial cell culture array device featured with integrated three-input, eight-output combinatorial mixer and cell culture chambers. The device is designed for cell-based screening of multiple compounds simultaneously on a microfluidic platform. The final assembled device is composed of a porous membrane integrated in between a Parylene 3-D microfluidic chip and a PDMS microfluidic chip. The membrane turned the cell culture chambers into two-level configuration to facilitate cell loading and to maintain cells in a diffusion dominated space during device operation. Experimentally, we first characterized the combined compound concentration profile at each chamber using a fluorescence method. We then successfully demonstrated the fu... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4168131 Wed, 10 Nov 2010 00:00:00 +0100 4168131 http://www.medworm.com/index.php?rid=4168132&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21057978%26dopt%3DAbstract This article describes a dynamic platform in which the biointerfacial properties of micro-patterned domains can be switched electrochemically through the spatio-temporally controlled dissolution and adsorption of polyelectrolyte coatings. Insulating SU-8 micro-patterns created on a transparent indium tin oxide electrode by photolithography allowed for the local control over the electrochemical dissolution of polyelectrolyte mono- and multilayers, with polyelectrolytes shielded from the electrochemical treatment by the underlying photoresist stencil. The platform allowed for the creation of micro-patterned cell co-cultures through the electrochemical removal of a non-fouling polyelectrolyte coating and the localized adsorption of a cell adhesive one after attachment of the first cell popula... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4168132 Sat, 06 Nov 2010 00:00:00 +0100 4168132 http://www.medworm.com/index.php?rid=4139825&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21053081%26dopt%3DAbstract Authors: Tran-Minh N, Dong T, Su Q, Yang Z, Jakobsen H, Karlsen F Clogging failure is common for microfilters in living cells concentration; for instance, the CaSki Cell-lines (Epidermoid cervical carcinoma cells) utilizing the flat membrane structure. In order to avoid the clogging, counter-flow concentration units with turbine blade-like micropillar are proposed in microconcentrator design. Due to the unusual geometrical-profiles and extraordinary microfluidic performance, the cells blocking does not occur even at permeate entrances. A counter-flow microconcentrator was designed, with both processing layer and collecting layer arranged in terms of the fractal based honeycomb structure. The device was optimized by coupling Artificial Neuron Network (ANN) and Computational Fluid Dynami... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4139825 Sat, 30 Oct 2010 00:00:00 +0100 4139825 http://www.medworm.com/index.php?rid=4139824&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21053082%26dopt%3DAbstract Authors: Chatterjee D, Amiroudine S A comprehensive non-isothermal Lattice Boltzmann (LB) algorithm is proposed in this article to simulate the thermofluidic transport phenomena encountered in a direct-current (DC) magnetohydrodynamic (MHD) micropump. Inside the pump, an electrically conducting fluid is transported through the microchannel by the action of an electromagnetic Lorentz force evolved out as a consequence of the interaction between applied electric and magnetic fields. The fluid flow and thermal characteristics of the MHD micropump depend on several factors such as the channel geometry, electromagnetic field strength and electrical property of the conducting fluid. An involved analysis is carried out following the LB technique to understand the significant influences of the... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4139824 Sat, 30 Oct 2010 00:00:00 +0100 4139824 http://www.medworm.com/index.php?rid=4139823&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D21053083%26dopt%3DAbstract Authors: Maltezos G, Lee J, Rajagopal A, Scholten K, Kartalov E, Scherer A Rapid decentralized biomedical diagnostics have become increasingly necessary in a medical environment of growing costs and mounting demands on healthcare personnel and infrastructure. Such diagnostics require low-cost novel devices that can operate at bedside or in doctor offices using small amounts of sample that can be extracted and processed on the spot. Thus, point-of-care sample preparation is an important component of the necessary diagnostic paradigm shift. We therefore introduce a microfluidic device which produces plasma from whole blood. The device is inexpensive, reliable, easy to fabricate, and requires only 3.5 kPa pressure to operate. The device is fully compatible with microfluidic diagnostic ch... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4139823 Sat, 30 Oct 2010 00:00:00 +0100 4139823 http://www.medworm.com/index.php?rid=4124679&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20981490%26dopt%3DAbstract Authors: Ciofani G, Ricotti L, Mattoli V The recent advancements in tissue engineering and, more in general, in cell-based applications, has led to an ever increasing interest toward new materials for sustained cell proliferation and differentiation. Here, the preparation and the characterization of scaffolds based on poly(lactic-co-glycolic) acid / barium titanate nanoparticle composites are presented. In vitro testing on H9C2 cell line demonstrates how the presence of the nanoparticles positively affects both the proliferation and the differentiation of this muscle-like cell line. Finally, the possibility to obtain porous scaffold and, therefore, an actual 3D culture system, is introduced. PMID: 20981490 [PubMed - as supplied by publisher] (Source: Biomedical Microdevices) Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4124679 Thu, 28 Oct 2010 00:00:00 +0100 4124679 http://www.medworm.com/index.php?rid=4108073&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20978852%26dopt%3DAbstract Authors: Gong Z, Zhao H, Zhang T, Nie F, Pathak P, Cui K, Wang Z, Wong S, Que L Usually cell-based assay is performed using titer plates. Because of the large library of chemical compounds, robust and rapid methods are required to find, refine and test a potential drug candidate in an efficient manner. In this article, the drug effects analysis on human breast cancer cells with a droplet microfluidic chip is reported. Each droplet serves as a nanoliter-volume titer plate and contains a human breast cancer cell MDA-MB-231, Cytochalasin D drug solution and cell viability indicator such as Calcein AM, which emits cytoplasmic green fluorescence. The drug effects on each cell are monitored in real time using a fluorescence microscope and by analyzing the fluorescence image of each cell. Cle... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4108073 Tue, 26 Oct 2010 23:00:00 +0100 4108073 http://www.medworm.com/index.php?rid=4108072&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20978853%26dopt%3DAbstract We report a novel three dimensional microfilter device that can enrich viable circulating tumor cells from blood. This device consists of two layers of parylene membrane with pores and gap precisely defined with photolithography. The positions of the pores are shifted between the top and bottom membranes. The bottom membrane supports captured cells and minimize the stress concentration on cell membrane and sustain cell viability during filtration. Viable cell capture on device was investigated with scanning electron microscopy, confocal microscopy, and immunofluorescent staining using model systems of cultured tumor cells spiked in blood or saline. The paper presents and validates this new 3D microfiltration concept for circulation tumor cell enrichment application. The device provides a h... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4108072 Tue, 26 Oct 2010 23:00:00 +0100 4108072 http://www.medworm.com/index.php?rid=4108071&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20978854%26dopt%3DAbstract Authors: Feng GH, Tsai JW The present paper examined a novel micromachined column structured Ion Polymer Metal Composite (IPMC) actuator with multidirectional control capability. The developed 4-electrode transducer enclosed a section of optical fiber, thereby allowing electronic directional control of conducted laser light. The fabricated device with IPMC actuator dimensions of 5 mm × 2 mm × 1 mm reached a maximum displacement of 400 μm when a square wave of 9 V was applied to the top-bottom electrode pair. Displacements in different directions and moving angles were characterized with side-side and top-right electrode pairs connected to the actuating signals. Furthermore, the generating moment per volt per second by the transducer was analyzed. The maximum value of ap... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4108071 Tue, 26 Oct 2010 23:00:00 +0100 4108071 http://www.medworm.com/index.php?rid=4108074&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20972888%26dopt%3DAbstract In this study, microelectrodes with the same surface modulation were implanted into the subcutaneous layers of Wistar rats. Nine rats were implanted with the microelectrodes and the total impedance data were measured every 24 h for 2 weeks after implantation. An equivalent electrical circuit model of the electrode-tissue interface was established and parameters were estimated by using an optimization algorithm. Four out of nine rats had manifested acute inflammation reaction and the rests revealed only slight tissue response. Histological examination for the inflammatory group showed fibroblasts, macrophages, and polymorphonuclear leukocytes in adjacent to the electrode contact surface. In the inflammatory group, no significantly difference in total impedance was found in both types of e... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4108074 Sat, 23 Oct 2010 23:00:00 +0100 4108074 http://www.medworm.com/index.php?rid=4088707&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20960063%26dopt%3DAbstract Authors: Ishikawa T, Fujiwara H, Matsuki N, Yoshimoto T, Imai Y, Ueno H, Yamaguchi T Bifurcations and confluences are very common geometries in biomedical microdevices. Blood flow at microchannel bifurcations has different characteristics from that at confluences because of the multiphase properties of blood. Using a confocal micro-PIV system, we investigated the behaviour of red blood cells (RBCs) and cancer cells in microchannels with geometrically symmetric bifurcations and confluences. The behaviour of RBCs and cancer cells was strongly asymmetric at bifurcations and confluences whilst the trajectories of tracer particles in pure water were almost symmetric. The cell-free layer disappeared on the inner wall of the bifurcation but increased in size on the inner wall of the confluenc... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4088707 Tue, 19 Oct 2010 23:00:00 +0100 4088707 http://www.medworm.com/index.php?rid=4088709&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20957436%26dopt%3DAbstract In this study, the real value of the proposed platform to maintain a stable and homogenous culture condition was discussed. Besides, the application of the presented platform for precisely investigating the effect of serum concentration on the metabolic activities and biosynthetic abilities of articular chondrocytes was also demonstrated. As a whole, the proposed device has paved an alternative route to carry out high throughput micro-scale 3-D perfusion cell culture in a simple, cost-effective and precise manner. The promising applications include 3-D cell culture-based high throughput drug or toxicity testing/screening, or other investigations on the cell biology, where the precise quantification of the links between the cellular responses and extracellular conditions is required. PM... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4088709 Mon, 18 Oct 2010 23:00:00 +0100 4088709 http://www.medworm.com/index.php?rid=4088708&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20957437%26dopt%3DAbstract Authors: Fujita H, Dau VT, Shimizu K, Hatsuda R, Sugiyama S, Nagamori E With the aim of designing a mechanical drug delivery system involving a bio-actuator, we fabricated a Micro Electro Mechanical Systems (MEMS) device that can be driven through contraction of skeletal muscle cells. The device is composed of a Si-MEMS with springs and ratchets, UV-crosslinked collagen film for cell attachment, and C2C12 muscle cells. The Si-MEMS device is 600 μm × 1000 μm in size and the width of the collagen film is 250 ~ 350 μm, which may allow the device to go through small blood vessels. To position the collagen film on the MEMS device, a thermo-sensitive polymer was used as the sacrifice-layer which was selectively removed with O(2) plasma at the positions where the collagen film ... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4088708 Mon, 18 Oct 2010 23:00:00 +0100 4088708 http://www.medworm.com/index.php?rid=4077884&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20949320%26dopt%3DAbstract Authors: Maezawa Y, Okano K, Matsubara M, Masuhara H, Hosokawa Y When nerve growth factor (NGF) is interacted with PC12 cells derived from rat pheochromocytoma, they are partially differentiated into neuron-like cells with neurites. In this work, PC12 cells differentiated by NGF were selectively isolated using a localized impulsive force in a μm-scale area, which was generated by focusing an infrared femtosecond laser into a cell culture medium. In order to evaluate the ability of the isolation method, differentiated and undifferentiated cells were isolated and their morphological changes after the isolation were compared. In both cases, their neurites were once contracted and some of them gradually regenerated day by day. When differentiated cells were isolated, the percentage of dif... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4077884 Thu, 14 Oct 2010 23:00:00 +0100 4077884 http://www.medworm.com/index.php?rid=4008479&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20865451%26dopt%3DAbstract Authors: Nieuwstadt HA, Seda R, Li DS, Fowlkes JB, Bull JL A simple passive microfluidic device that continuously separates microparticles is presented. Its development is motivated by the need for specific size micro perfluorocarbon (PFC) droplets to be used for a novel gas embolotherapy method. The device consists of a rectangular channel in which inertial lift forces are utilized to separate particles in lateral distance. At the entrance of the channel, particles are introduced at the center by focusing the flow from a center channel with flow from two side channels. Downstream, large particles will occupy a lateral equilibrium position in shorter axial distance than small particles. At the exit of the channel, flow containing large particles is separated from flow containing small ... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4008479 Thu, 23 Sep 2010 23:00:00 +0100 4008479 http://www.medworm.com/index.php?rid=4008480&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20862610%26dopt%3DAbstract Authors: Jeon H, Kim E, Grigoropoulos CP Contractility of cells in wound site is important to understand pathological wound healing and develop therapeutic strategies. In particular, contractile force generated by cells is a basic element for designing artificial three-dimensional cell culture scaffolds. Direct assessment of deformation of three-dimensional structured materials has been used to calculate contractile forces by averaging total forces with respect to the cell population number. However, macroscopic methods have offered only lower bounds of contractility due to experimental assumptions and the large variance of the spatial and temporal cell response. In the present study, cell contractility was examined microscopically in order to measure contractile forces generated by in... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=4008480 Wed, 22 Sep 2010 23:00:00 +0100 4008480 http://www.medworm.com/index.php?rid=3982247&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20842530%26dopt%3DAbstract Authors: Khan OF, Sefton MV To study the effect of disturbed flow patterns on endothelial cells, the channels found within a modular tissue engineering construct were reproduced in a microfluidic chip and lined with endothelial cells whose resulting phenotype under flow was assessed using confocal microscopy. Modular tissue engineered constructs formed by the random packing of sub-millimetre, cylindrically shaped, endothelial cell-covered modules into a larger container creates interconnected channels that permit the flow of fluids such as blood. Due to the random packing, the flow path is tortuous and has the potential to create disturbed flow, resulting in an activated endothelium. At an average shear stress of 2.8 dyn cm( -2), endothelial cells within channels of varying geometri... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=3982247 Tue, 14 Sep 2010 23:00:00 +0100 3982247 http://www.medworm.com/index.php?rid=3982246&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20842531%26dopt%3DAbstract Authors: Su WT Stromal cells alter their mode of attachment, cellular shape, and protein expression when placed on square arrays of micro-pillars. All the pillars we studied had 50 μm diameters, 85 μm pillar heights, were separated by 50 μm, and had an identical surface chemistry. We found that these micro-pillars provided many opportunities for mechanical interlocking and were more suitable attachment matrixes for cell adhesion and stretching of the overlying biomaterials. When the feeder layer cells of hematopoietic stem cells (HSCs) were cultured into the micro-pillar device, they could screen more hematopoietic cytokines, such as interleukin-3 (IL-3), and laminin into the medium. Consequently, the micro-pillar device provides a greater degree of HSCs expansion rel... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=3982246 Tue, 14 Sep 2010 23:00:00 +0100 3982246 http://www.medworm.com/index.php?rid=3982251&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20838900%26dopt%3DAbstract Authors: Henle C, Raab M, Cordeiro JG, Doostkam S, Schulze-Bonhage A, Stieglitz T, Rickert J A novel computer aided manufacturing (CAM) method for electrocorticography (ECoG) microelectrodes was developed to be able to manufacture small, high density microelectrode arrays based on laser-structuring medical grade silicone rubber and high purity platinum. With this manufacturing process, we plan to target clinical applications, such as presurgical epilepsy monitoring, functional imaging during cerebral tumor resections and brain-computer interface control in paralysed patients, in the near future. This paper describes the manufacturing, implantation and long-term behaviour of such an electrode array. In detail, we implanted 8-channel electrode arrays subdurally over rat cerebral cortex o... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=3982251 Mon, 13 Sep 2010 23:00:00 +0100 3982251 http://www.medworm.com/index.php?rid=3982250&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20838901%26dopt%3DAbstract Authors: Azam A, Laflin KE, Jamal M, Fernandes R, Gracias DH We demonstrate self-folding of precisely patterned, optically transparent, all-polymeric containers and describe their utility in mammalian cell and microorganism encapsulation and culture. The polyhedral containers, with SU-8 faces and biodegradable polycaprolactone (PCL) hinges, spontaneously assembled on heating. Self-folding was driven by a minimization of surface area of the liquefying PCL hinges within lithographically patterned two-dimensional (2D) templates. The strategy allowed for the fabrication of containers with variable polyhedral shapes, sizes and precisely defined porosities in all three dimensions. We provide proof-of-concept for the use of these polymeric containers as encapsulants for beads, chemicals, mamm... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=3982250 Mon, 13 Sep 2010 23:00:00 +0100 3982250 http://www.medworm.com/index.php?rid=3982249&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20838902%26dopt%3DAbstract Authors: Au SH, Shih SC, Wheeler AR We introduce a micro-scale bioreactor for automated culture and density analysis of microorganisms. The microbioreactor is powered by digital microfluidics (DMF) and because it is used with bacteria, algae and yeast, we call it the BAY microbioreactor. Previous miniaturized bioreactors have relied on microchannels which often require valves, mixers and complex optical systems. In contrast, the BAY microbioreactor is capable of culturing microorganisms in distinct droplets on a format compatible with conventional bench-top analyzers without the use of valves, mixers or pumps. Bacteria, algae and yeast were grown for up to 5 days with automated semi-continuous mixing and temperature control. Cell densities were determined by measuring absorbances th... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=3982249 Mon, 13 Sep 2010 23:00:00 +0100 3982249 http://www.medworm.com/index.php?rid=3982248&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20838903%26dopt%3DAbstract Authors: Du G, Ravetto A, Fang Q, den Toonder JM We introduce a simple micro-fluidic device containing an actuated flexible membrane, which allows the viscoelastic characterization of cells in small volumes of suspension by loading them in compression and observing the cell deformation in time. From this experiment, we can determine the characteristic time constant of recovery of the cell. To validate the device, two cell types known to have different cytoskeletal structures, 3T3 fibroblasts and HL60 cells, are tested. They show a substantially different response in the device and can be clearly distinguished on the basis of the measured characteristic recovery time constant. Also, the effect of breaking down the actin network, a main mechanical component of the cytoskeleton, by a trea... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=3982248 Mon, 13 Sep 2010 23:00:00 +0100 3982248 http://www.medworm.com/index.php?rid=3982252&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20830527%26dopt%3DAbstract In this study, we show that the morphology of tumor epithelial cells cultured on nanorods is rounded compared to flat surfaces and associated with decreased cellular stiffness and non-muscle myosin II phosphorylation. Tumor cell viability and proliferation was unchanged on nanorods. Adherent cell numbers were significantly decreased while single tumor cell motility was increased on nanorods compared to flat surfaces. Together, these results suggest that nanorods can be used to weaken malignant tumor cell adhesion, and therefore potentially improve tumor stent performance. PMID: 20830527 [PubMed - as supplied by publisher] (Source: Biomedical Microdevices) Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=3982252 Thu, 09 Sep 2010 23:00:00 +0100 3982252 http://www.medworm.com/index.php?rid=3955702&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20827509%26dopt%3DAbstract Authors: Marasso SL, Giuri E, Canavese G, Castagna R, Quaglio M, Ferrante I, Perrone D, Cocuzza M Lab-on-chips (LOCs) are critical systems that have been introduced to speed up and reduce the cost of traditional, laborious and extensive analyses in biological and biomedical fields. These ambitious and challenging issues ask for multi-disciplinary competences that range from engineering to biology. Starting from the aim to integrate microarray technology and microfluidic devices, a complex multilevel analysis platform has been designed, fabricated and tested (All rights reserved-IT Patent number TO2009A000915). This LOC successfully manages to interface microfluidic channels with standard DNA microarray glass slides, in order to implement a complete biological protocol. Typical Micro El... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=3955702 Wed, 08 Sep 2010 23:00:00 +0100 3955702 http://www.medworm.com/index.php?rid=3955703&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20820923%26dopt%3DAbstract This article describes a simple microfluidic method to fabricate chitosan-silica hybrid microspheres in one step. We dissolved tetraethoxysilane (TEOS) into a chitosan/acetic acid aqueous solution to form a chitosan-silica sol, and then emulsified it in an organic phase mainly containing n-octanol and an organic base triotylamine (TOA) via a co-axial microfluidic device. The formed aqueous droplets were solidified because of the extraction of acetic acid and water to the organic phase. The simple method presented has the advantages of controllable sphere diameter, narrow size distribution and good sphericity. The porous structures of the microspheres were displayed by SEM images. It is found that the inner and surface structures can be controlled by adjusting the solidification reagent com... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=3955703 Mon, 06 Sep 2010 23:00:00 +0100 3955703 http://www.medworm.com/index.php?rid=3934756&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20814745%26dopt%3DAbstract Authors: Breton F, Bennetau B, Lidereau R, Thomas L, Regnier G, Ehrhart JC, Tauc P, Tran PL We have recently reported the analytical performance of an immunosensor comprising one mm-scale parallel plate laminar flow chamber and applied to capture MCF7 breast cancer cells (Ehrhart et al., Biosens. Bioelectr. 24, 467, 2008). Herein we present a new multiplex immunosensor embodying four parallel plate laminar flow chambers that fit onto a standard, functionalized, microscopy glass slide. The four surfaces are coated with long alkyl chain spacers of 21-aminohenicosyl trichlorosilane (AHTS) and then grafted with a monoclonal anti-human epithelial cell adhesion molecule (EpCAM) antibody specific of target cells to immobilize. We first demonstrate a significantly (P < 0.01) improved capaci... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=3934756 Thu, 02 Sep 2010 23:00:00 +0100 3934756 http://www.medworm.com/index.php?rid=3934757&cid=s_37610_169_f&fid=37610&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20809277%26dopt%3DAbstract Authors: Chowdhury MM, Katsuda T, Montagne K, Kimura H, Kojima N, Akutsu H, Ochiya T, Fujii T, Sakai Y Pluripotent stem cells are under the influence of soluble factors in a diffusion dominant in vivo microenvironment. In order to investigate the effects of secreted soluble factors on embryonic stem cell (ESC) behavior in a diffusion dominant microenvironment, we cultured mouse ESCs (mESCs) in a membrane-based two-chambered micro-bioreactor (MB). To avoid disturbing the cellular environment in the top chamber of the MB, only the culture medium of the bottom chamber was exchanged. Cell growth in the MB after 5 days of culture was similar to that in conventional 6-well plate (6-WP) and membrane-based Transwell insert (TW) cultures, indicating adequate nutrient supply in the MB. However, ... Biomedical Microdevices journals http://www.medworm.com/rss/comments.php?id=3934757 Tue, 31 Aug 2010 23:00:00 +0100 3934757