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 'Microfluidics and Nanofluidics' source. Tue, 07 Feb 2012 10:30:12 +0100 http://www.medworm.com/index.php?rid=5603113&cid=s_38174_174_f&fid=38174&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22247719%26dopt%3DAbstract This article presents a three-dimensional analytical model to investigate cross-stream diffusion transport in rectangular microchannels with arbitrary aspect ratios under pressure-driven flow. The Fourier series solution to the three-dimensional convection-diffusion equation is obtained using a double integral transformation method and associated eigensystem calculation. A phase diagram derived from the dimensional analysis is presented to thoroughly interrogate the characteristics in various transport regimes and examine the validity of the model. The analytical model is verified against both experimental and numerical models in terms of the concentration profile, diffusion scaling law, and mixing efficiency with excellent agreement (with <0.5% relative error). Quantitative comparison ... Microfluidics and Nanofluidics journals http://www.medworm.com/rss/comments.php?id=5603113 Sun, 01 Jan 2012 05:00:00 +0100 5603113 http://www.medworm.com/index.php?rid=5475632&cid=s_38174_174_f&fid=38174&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D22140373%26dopt%3DAbstract In this report, we provide a framework for understanding flow in simple 2DPNs using experiments, analytical expressions, and computational simulations. PMID: 22140373 [PubMed - as supplied by publisher] (Source: Microfluidics and Nanofluidics) Microfluidics and Nanofluidics journals http://www.medworm.com/rss/comments.php?id=5475632 Sat, 01 Jan 2011 05:00:00 +0100 5475632 http://www.medworm.com/index.php?rid=4090164&cid=s_38174_174_f&fid=38174&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20953263%26dopt%3DAbstract Authors: Lee JH, Han J Here, we report a new method of concentration-enhanced binding kinetics for a rapid immunoassay screening test on a gold surface in a poly(dimethylsiloxane) (PDMS) microfluidic chip format. The use of alkylthiolate self-assembled monolayers on gold surfaces of a PDMS-glass microchip resulted in accelerated binding kinetics of Human chorionic gonadotropin (hCG) at an electrokinetic trapping zone. We used a PBS solution (buffer concentration ~ 150 mM), not a dibasic buffer system (~10 mM), for the dynamic preconcentrating operation and the preconcentration of cy3 labeled streptavidin onto biotinylated Au surface revealed that the binding kinetics of the protein were linearly proportional to the concentration profile of the preconcentration plug. We showed rapid det... Microfluidics and Nanofluidics journals http://www.medworm.com/rss/comments.php?id=4090164 Thu, 30 Sep 2010 23:00:00 +0100 4090164 http://www.medworm.com/index.php?rid=4065934&cid=s_38174_174_f&fid=38174&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20930933%26dopt%3DAbstract We describe a new microfluidic approach for creating slugs in air, each comprising a size and composition that can be selected individually for each slug. Two-component slugs are formed by first metering the desired volume of each reagent, merging the two volumes into an end-to-end slug, and propelling the slug to induce mixing. Volume control is achieved by a novel mechanism: two closed chambers on the chip are initially filled with air, and a valve in each is briefly opened to admit one of the reagents. The pressure of each reagent can be individually selected and determines the amount of air compression, and thus the amount of liquid that is admitted into each chamber. We describe the theory of operation, characterize the slug generation chip, and demonstrate the creation of slugs of di... Microfluidics and Nanofluidics journals http://www.medworm.com/rss/comments.php?id=4065934 Thu, 30 Sep 2010 23:00:00 +0100 4065934 http://www.medworm.com/index.php?rid=4065933&cid=s_38174_174_f&fid=38174&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20938490%26dopt%3DAbstract Authors: Chang DS, Langelier SM, Zeitoun RI, Burns MA Pressure-driven flow control systems are a critical component in many microfluidic devices. Compartmentalization of this functionality into a stand-alone module possessing a simple interface would allow reduction of the number of pneumatic interconnects required for fluidic control. Ideally, such a module would also be sufficiently compact for implementation in portable platforms. In our current work, we show the feasibility of using a modular array of Venturi pressure microregulators for coordinated droplet manipulation. The arrayed microregulators share a single pressure input and are capable of outputting electronically controlled pressures that can be independently set between ±1.3 kPa. Because the Venturi microregulator operat... Microfluidics and Nanofluidics journals http://www.medworm.com/rss/comments.php?id=4065933 Thu, 30 Sep 2010 23:00:00 +0100 4065933 http://www.medworm.com/index.php?rid=4065935&cid=s_38174_174_f&fid=38174&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20927185%26dopt%3DAbstract Authors: Malleo D, Nevill JT, Lee LP, Morgan H A device for continuous differential impedance analysis of single cells held by a hydrodynamic cell trapping is presented. Measurements are accomplished by recording the current from two closely-situated electrode pairs, one empty (reference) and one containing a cell. We demonstrate time-dependent measurement of single cell impedance produced in response to dynamic chemical perturbations. First, the system is used to assay the response of HeLa cells to the effects of the surfactant Tween, which reduces the impedance of the trapped cells in a concentration dependent way and is interpreted as gradual lysis of the cell membrane. Second, the effects of the bacterial pore-forming toxin, Streptolysin-O are measured: a transient exponential deca... Microfluidics and Nanofluidics journals http://www.medworm.com/rss/comments.php?id=4065935 Sat, 31 Jul 2010 23:00:00 +0100 4065935 http://www.medworm.com/index.php?rid=3855696&cid=s_38174_174_f&fid=38174&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20694166%26dopt%3DAbstract This article presents a microfluidic device which integrates autonomous serial immunofluorocytometry binding reactions of cytometric beads with fluorescence detection and quantification in a continuous flow environment. The microdevice assay is intended to alleviate the extensive benchwork and large sample volumes used when conducting traditional immunoassays, without requiring complex external controls. The technology is based on the miniaturization and automation of the serial processing steps of an antigen sandwich immunoassay, with integrated fluorescence detection using paramagnetic microbeads. The continuous flow design may enable temporal tracking of time-varying protein concentrations in a continuously infused sample for clinical applications, specifically for monitoring inflammati... Microfluidics and Nanofluidics journals http://www.medworm.com/rss/comments.php?id=3855696 Sat, 31 Jul 2010 23:00:00 +0100 3855696 http://www.medworm.com/index.php?rid=3583902&cid=s_38174_174_f&fid=38174&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20473353%26dopt%3DAbstract Authors: Li L, Fu Q, Kors CA, Stewart L, Nollert P, Laible PD, Ismagilov RF This paper presents a plug-based microfluidic system to dispense nanoliter-volume plugs of Lipidic Cubic Phase (LCP) material and subsequently merge the LCP plugs with aqueous plugs. This system was validated by crystallizing membrane proteins in lipidic mesophases, including LCP. This system allows for accurate dispensing of LCP material in nanoliter volumes, prevents inadvertent phase transitions that may occur due to dehydration by enclosing LCP in plugs, and is compatible with the traditional method of forming LCP material using a membrane protein sample, as shown by the successful crystallization of bacteriorhodopsin from Halobacterium salinarum. Conditions for the formation of LCP plugs were characterized... Microfluidics and Nanofluidics journals http://www.medworm.com/rss/comments.php?id=3583902 Fri, 21 May 2010 14:06:12 +0100 3583902 http://www.medworm.com/index.php?rid=3429724&cid=s_38174_174_f&fid=38174&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20352022%26dopt%3DAbstract Authors: Park JY, Morgan M, Sachs AN, Samorezov J, Teller R, Shen Y, Pienta KJ, Takayama S Conventional cell trapping methods using microwells with small dimensions (10-20 mum) are useful for examining the instantaneous cell response to reagents; however, such wells have insufficient space for longer duration screening tests that require observation of cell attachment and division. Here we describe a flow method that enables single cell trapping in microwells with dimensions of 50 mum, a size sufficient to allow attachment and division of captured cells. Among various geometries tested, triangular microwells were found to be most efficient for single cell trapping while providing ample space for cells to grow and spread. An important trapping mechanism is the formation of fluid streaml... Microfluidics and Nanofluidics journals http://www.medworm.com/rss/comments.php?id=3429724 Mon, 01 Feb 2010 00:00:00 +0100 3429724 http://www.medworm.com/index.php?rid=3239913&cid=s_38174_174_f&fid=38174&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D20126306%26dopt%3DAbstract Authors: Wang X, Cheng C, Wang S, Liu S Electroosmotic pumping is receiving increasing attention in recent years owing to the rapid development in micro total analytical systems. Compared with other micropumps, electroosmotic pumps (EOPs) offer a number of advantages such as creation of constant pulse-free flows and elimination of moving parts. The flow rates and pumping pressures of EOPs matches well with micro analysis systems. The common materials and fabrication technologies make it readily integrateable with lab-on-a-chip devices. This paper reviews the recent progress on EOP fabrications and applications in order to promote the awareness of EOPs to researchers interested in using micro- and nano-fluidic devices. The pros and cons of EOPs are also discussed, which helps these rese... Microfluidics and Nanofluidics journals http://www.medworm.com/rss/comments.php?id=3239913 Sun, 01 Feb 2009 00:00:00 +0100 3239913 http://www.medworm.com/index.php?rid=2000534&cid=s_38174_174_f&fid=38174&url=http%3A%2F%2Fwww.ncbi.nlm.nih.gov%2Fentrez%2Fquery.fcgi%3Ftmpl%3DNoSidebarfile%26db%3DPubMed%26cmd%3DRetrieve%26list_uids%3D18806888%26dopt%3DAbstract Authors: Erickson D, Mandal S, Yang AH, Cordovez B Next generation biosensor platforms will require significant improvements in sensitivity, specificity and parallelity in order to meet the future needs of a variety of fields ranging from in vitro medical diagnostics, pharmaceutical discovery and pathogen detection. Nano-biosensors, which exploit some fundamental nanoscopic effect in order to detect a specific biomolecular interaction, have now been developed to a point where it is possible to determine in what cases their inherent advantages over traditional techniques (such as nucleic acid microarrays) more than offset the added complexity and cost involved constructing and assembling the devices. In this paper we will review the state of the art in nanoscale biosensor technologies, ... Microfluidics and Nanofluidics journals http://www.medworm.com/rss/comments.php?id=2000534 Mon, 01 Dec 2008 17:38:09 +0100 2000534