IET Nanobiotechnology via MedWorm.com

Digital microfluidic operations on micro-electrode dot array architecture

IET Nanobiotechnology — Thu, 01 Dec 2011 05:00:00 +0100

This study presents the analysis and experiments of digital microfluidic operations on a novel electrowetting-on-dielectric-based `micro-electrode dot array architecture?? that fosters a development path for hierarchical top-down design approach for digital microfluidics. The proposed architecture allows dynamic configurations and activations of identical basic microfluidic unit called `micro-electrode cells?? to design microfluidic components, layouts, routing, microfluidic operations and applications of the biochip hierarchically. Fundamental microfluidic operations have been successfully performed by the architecture. In addition, this novel architecture demonstrates a number of advantages and flexibilities over the conventional digital microfluidics in performing advanced microfluidic ...

Experiment and simulation of resistance of nanoporous dentin biomaterial to CO2 laser irradiation

IET Nanobiotechnology — Thu, 01 Dec 2011 05:00:00 +0100

The resistance of nanoporous dentin biomaterial to CO2 laser irradiation was investigated by experiment and simulation for potential tooth hypersensitivity treatment. The controlled parameters including laser power of 0.03??0.150 W, scanning speeds of 11.4??34.2 mm/s and focus/defocus modes were used for studying interaction between laser energy and dentin of human tooth. Most of the dentin specimens were etched after CO2 laser irradiation with the power larger than 0.12 W at a scanning speed of 11.4 mm/s. Compared with the simulation results of temperature distribution, the maximum temperature at laser powers from 0.12 to 0.15 W is increased from 1961 to 2245°C, which exceeded the melting point (1570°C) of dentin's main content hydroxyapatite (HA). Increasing scanning spee...

Wireless and batteryless biomedical microsystem for neural recording and epilepsy suppression based on brain focal cooling

IET Nanobiotechnology — Thu, 01 Dec 2011 05:00:00 +0100

This work presents a biomedical microsystem with a wireless radiofrequency (RF)-powered electronics and versatile sensors/actuators for use in nanomedicinal diagnosis and therapy. The cooling of brain tissue has the potential to reduce the frequency and severity of epilepsy. Miniaturised spiral coils as a wireless power module with low-dropout linear regulator circuit convert RF signals into a DC voltage, can be implanted without a battery in monitoring free behaviour. A thermoelectric (TE) cooler is an actuator that is employed to cool down brain tissue to suppress epilepsy. Electroencephalogram (EEG) electrodes and TE coolers are integrated to form module that is placed inside the head of a rat and fastened with a biocompatible material. EEG signals are used to identify waveforms associa...

XPS and NEXAFS studies of VUV/O3-treated aromatic polyurea and its application to microchip electrophoresis

IET Nanobiotechnology — Thu, 01 Dec 2011 05:00:00 +0100

In this study, the authors performed X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure (NEXAFS) studies of vacuum ultraviolet (VUV)/O3-treated aromatic polyurea films to investigate their treatment effects. XPS and NEXAFS spectra indicate that the benzene ring was cleaved after treatment and that carboxyl, hydroxyl, ketone and aldehyde groups were formed at the cleaved sites. The VUV/O3-treated polyurea film was applied to a polymethylmethacrylate (PMMA) microchip for microchip electrophoresis (MCE) of bovine serum albumin (BSA). Fast electro-osmotic mobility of 4.6 ?? 10-4 cm2/V/s as well as reduction of the BSA adhesion was achieved. This functional surface is useful for high-speed MCE analysis. (Source: IET Nanobiotechnology)

DNA as a template in self-assembly of Au nano-structure

IET Nanobiotechnology — Thu, 01 Dec 2011 05:00:00 +0100

In this study, an alkanethiol-assisted self-assembly of Au nano-particles and its size tunable technique were confirmed. To fabricate a one-dimensional (1D) template, λ-DNA was first laid on mica substrate by dropping diluted λ-DNA solution, 12.6 ng/μml, on freshly cleaved mica. By dropping colloidal gold solution on mica surface with the DNA templates laid on it, the λ-DNA was then pulled straight via capillary force by applying solvent absorbing tissue at outer circumference of the mica substrate. Moreover, it fixed on mica via gravity force and Van der Waals force between mica surface and the DNA. Au nano-particles would be arrayed along the straight DNA molecules to form 1D Au arrays. Then based on the synthesis of 1D nano-structure via DNA template and ...

Portable potentiostatic sensor integrated with neopterin-imprinted poly(ethylene-co-vinyl alcohol)-based electrode

IET Nanobiotechnology — Thu, 01 Dec 2011 05:00:00 +0100

Neopterin is a catabolic product of guanosine triphosphate, a purine nucleotide. Measuring neopterin concentrations in biological fluids such as urine provides information about cellular immune activation in humans under control of T helper cells. A high neopterin concentration in bodily fluids, including serum and urine, indicates cellular immunity activation, which is associated with oxidative stress. In this work, neopterin is the target molecule and imprinted onto poly(ethylene-co-vinyl alcohol) via solvent evaporation. The template molecules on the thin film are then removed, and the membrane is used as a sensing element for electrochemical urinalysis. Poly(ethylene-co-vinyl alcohol) containing 27 mol% ethylene had high imprinting effectiveness and may be integrated with the proposed ...

Viscosity??density sensor with resonant torsional paddle for direct detection in liquid

IET Nanobiotechnology — Thu, 01 Dec 2011 05:00:00 +0100

A novel micro-machined biosensor based on the resonant torsional paddle with electromagnetic excitation which can work in liquid directly is presented. The sensor designed consists of two paddles with resonant torsional mode, in which the energy loss of the resonator during the vibration is so lower that it can be suitable for detection in liquid. Finite element method analysis was carried out to guarantee the sensitivity of the sensor. Micro electro-mechanical system (MEMS) bulk silicon processes were adopted to accomplish the fabrication. A positive-feedback circuit with energy compensation is designed to improve the characteristics of the sensor in liquid. Experiments show that the resonant torsional paddle can work directly in liquid and the Q-factor of the sensor in liquid can be impr...

Development of a low-cost magnetic microfluidic chip for circulating tumour cell capture

IET Nanobiotechnology — Thu, 01 Dec 2011 05:00:00 +0100

The authors have developed a novel fabrication process for a selective micro-magnetic activated cell sorting (MACS) chip based on ferromagnetic material encapsulated micropillars (FMEMs), which is technically simple and low cost. The FMEM produces a high field gradient to magnetically attract, capture and hold cells on its interface. System test simulations were carried out to predict the efficacy of target capture and verify that the actual magnetic particles behaviour agreed well with model predictions. To determine the ability of the novel microMACS chip to capture circulating tumour cells (CTCs), SW620 human colon cancer cells were used in an in vitro flow model system and were able to be captured with the efficiency of 72.8%. The obvious accumulation of CTCs at a certain location on t...

Nanochannel system fabricated by MEMS microfabrication and atomic force microscopy

IET Nanobiotechnology — Thu, 01 Dec 2011 05:00:00 +0100

A silicon nanochannel system with integrated transverse electrodes was designed and fabricated by combining microelectro- mechanical systems (MEMS) micromachining and atomic force microscopy (AFM)-based nanolithography. The fabrication process began with the patterning of microscale reservoirs and electrodes on an oxidised silicon chip using conventional MEMS techniques. A nanochannel, approximately 30 μm long with a small semi-circular cross-sectional area of 20 nm ?? 200 nm, was then mechanically machined on the oxide surface between the micro reservoirs by applying AFM nanolithography with an all-diamond probe. Anodic bonding was used to seal off the nanochannel with a matching Pyrex cover. Continuous flow in the nanochannel was verified by pressurising a solution of fluorescein...

Editorial: Special Issue for the 6th IEEE International Conference on Nano/Micro Engineered and Molecular Systems (IEEE-NEMS 2011)

IET Nanobiotechnology — Thu, 01 Dec 2011 05:00:00 +0100

The IEEE-NEMS 2011 was held in Kaohsiung, Taiwan, on February 20??23, 2011. As a premier conference in the field of micro- and nano-technology, it attracted leading scholars and researchers to publish their latest and advanced findings in this event. (Source: IET Nanobiotechnology)

Review of the theory of generalised dielectrophoresis

IET Nanobiotechnology — Thu, 01 Sep 2011 04:00:00 +0100

Discussions are provided for the application of the theory to nano-sized particles. The authors also illustrate some features of the Clausius??Mossotti factor using erythrocyte as an example, including both the crossover (DEP) and peak frequencies (ER) at low and high-frequency limits. (Source: IET Nanobiotechnology)

Effects of poly(lactic-co-glycolic acid) on preparation and characteristics of plasmid DNA-loaded solid lipid nanoparticles

IET Nanobiotechnology — Thu, 01 Sep 2011 04:00:00 +0100

Poly(lactic-co-glycolic acid) (PLGA) was used as a polymeric emulsifier to encapsulate plasmid DNA into hydrogenated castor oil (HCO)-solid lipid nanoparticles (SLN) by w/o/w double emulsion and solvent evaporation techniques. The effects of PLGA on the preparation, characteristics and transfection efficiency of DNA-loaded SLN were studied. The results showed that PLGA was essential to form the primary w/o emulsion and the stability of the emulsion was enhanced with the increase of PLGA content. DNA-loaded SLN were spherical with smooth surfaces. The SLN had a negative charge in weak acid and alkaline environment but acquired a positive charge in acidic pH and the cationisation capacity of the SLN increased with the increase of PLGA/HCO ratio. Agarose gel electrophoresis demonstrated that ...

Polysaccharides and phytochemicals: a natural reservoir for the green synthesis of gold and silver nanoparticles

IET Nanobiotechnology — Thu, 01 Sep 2011 04:00:00 +0100

Currently, sustainability initiatives that use green chemistry to improve and/or protect our global environment are becoming focal issues in many fields of research. Instead of using toxic chemicals for the reduction and stabilisation of metallic nanoparticles, the use of various biological entities has received considerable attention in the field of nanobiotechnology. Among the many possible natural products, polysaccharides and biologically active plant products represent excellent scaffolds for this purpose. Polysaccharides have hydroxyl groups, a hemiacetal reducing end, and other functionalities that can play important roles in both the reduction and the stabilisation of metallic nanoparticles. Among the various categories of compounds in plants that have potent biological activities,...

Optimum coding framework for error detection in the self-assembly of the Sierpinski triangle

IET Nanobiotechnology — Thu, 01 Sep 2011 04:00:00 +0100

This study presents a coding framework by which DNA self-assembly can be analysed for error detection. The proposed framework relies on coding and mapping functions that allow establishing the correctness of bonding each tile based on the codes of the tiles along a so-called traversal path. This method is different from the one that relies on comparing the pattern to be assembled (as defined by the tile set) and the current aggregate (as resulting from previously assembled tiles). As a widely used pattern and instantiation of this process, the Sierpinski triangle self-assembly is analysed in detail. The Sierpinski triangle is therefore utilised as an example to show the application of the proposed method. Different properties are proposed and its optimum coding is achieved for error detect...

One-step synthesis of highly biocompatible multi-shaped gold nanostructures with fruit extract

IET Nanobiotechnology — Sat, 30 Apr 2011 15:15:45 +0100

This study opens the exciting possibility of synthesising various multi-shaped nanoparticles through a simple and green approach, as well as paving the way for future bio-applications. (Source: IET Nanobiotechnology)

Comparison of quantum-dots- and fluoresceinisothiocyanate- based technology for detecting prostate-specific antigen expression in human prostate cancer

IET Nanobiotechnology — Sat, 30 Apr 2011 15:15:45 +0100

In this study, the authors evaluated the sensitivity and stability of quantum-dots-based immunolabelling, in comparison with the conventional fluorescein-isothiocyanate-based immunolabelling (FITC), for detecting prostate-specific antigen (PSA) expression in human prostate cancer. The authors?? data revealed that the two methods had similar sensitivity in differential display of the PSA expression correlated with tumour stage and grade (k = 0.88, p < 0.001). Moreover, the intensity of QDs fluorescence remain stable for 10 days after conjugation to the PSA protein in 97% of the cases and more than 1 month in 92% of the cases, although the FITC fluorescence became undetectable after 6 min for all cases. (Source: IET Nanobiotechnology)

Adhesion, proliferation and differentiation of pluripotent stem cells on multi-walled carbon nanotubes

IET Nanobiotechnology — Sat, 30 Apr 2011 15:15:44 +0100

This article studies the adhesion, growth and differentiation of stem cells on carbon nanotube matrices. Glass coverslips were coated with multi-walled carbon nanotube (MWNT) thin films using layer-by-layer self-assembling techniques. Pluripotent P19 mouse embryonal carcinoma stem cells were seeded onto uncoated or MWNT-coated glass coverslips and either maintained in an undifferentiated state or induced to differentiate by the addition of retinoic acid. The authors found that cell adhesion was increased on the MWNT-coated glass surfaces, and that the expression patterns of some differentiation markers were altered in cells grown on MWNTs. The results suggest that MWNTs will be useful in directing pluripotent stem cell differentiation for tissue engineering purposes. (Source: IET Nanobiote...

Cytotoxic effects of MgO nanoparticles on human umbilical vein endothelial cells in vitro

IET Nanobiotechnology — Sat, 30 Apr 2011 15:15:44 +0100

In this study, the cytotoxicity of MgO nanoparticles on human umbilical vein endothelial cells (HUVECs) in vitro was examined. The morphology and size of MgO nanoparticles were analysed by the transmission electron microscope (TEM) and nanoparticle size analyser. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2 h-tetrazolium bromide) assay, 4??,6-diamidino-2-phenylindole (DAPI) staining analysis, NO release and total antioxidation competence (T-AOC) assay were used to evaluate the cytotoxicity of MgO nanoparticles. The results showed that most MgO nanoparticles were spherical with agglomerated state and the diameter of single particle was about 100 nm. Meanwhile, low concentration (below 200 mg/ml) of MgO nanoparticles suspension showed no cytotoxicity by MTT assay. However, once the conce...

Investigating purine-functionalised carbon nanotubes and their properties: a computational approach

IET Nanobiotechnology — Sat, 30 Apr 2011 15:15:44 +0100

Density functional theory calculations were performed to investigate the properties of purine-functionalised carbon nanotube (CNT), including adenine and guanine functionalised models (CNT-A and CNT-G). The results indicated that the CNT-G model could be better dispersed in the hydrated systems, whereas the CNT-A model could be expected as a more favourably stable structure. The results also indicated that the quadrupole coupling constant (CQ) for the nitrogen atoms of the CNT-G model detects more significant changes than the CNT-A model with respect to the individual guanine and adenine structures. (Source: IET Nanobiotechnology)

Development of rapid oral bacteria detection apparatus based on dielectrophoretic impedance measurement method

IET Nanobiotechnology — Sat, 30 Apr 2011 15:15:43 +0100

In this study, a bacteria detection apparatus based on dielectrophoretic impedance measurement (DEPIM) method was demonstrated for rapid evaluation of oral hygiene. The authors integrated a micro electrode chip on which bacteria were captured by dielectrophoresis (DEP), an AC voltage source to induce DEP force, and an impedance measurement circuit to a portable instrument that enables rapid and automated oral bacterial inspection in hospitals and clinics. Special considerations have been made on effects of high electrical conductivity of oral samples on DEP force and DEPIM results. It was shown experimentally and theoretically that using a higher electric field frequency for the DEP bacteria trap and the impedance measurement could realise DEPIM application to bacteria inspection from oral...

Interaction of gold nanoparticles with Pfu DNA polymerase and effect on polymerase chain reaction

IET Nanobiotechnology — Tue, 25 Jan 2011 14:47:56 +0100

The interaction of gold nanoparticles with Pfu DNA polymerase has been investigated by a number of biological, optical and electronic spectroscopic techniques. Polymerase chain reaction was performed to show gold nanoparticles' biological effect. Ultraviolet¿visible and circular dichroism spectra analysis were applied to character the structure of Pfu DNA polymerase after conjugation with gold nanoparticles. X-ray photoelectron spectroscopy was used to investigate the bond properties of the polymerase-gold nanoparticles complex. The authors demonstrate that gold nanoparticles do not affect the amplification efficiency of polymerase chain reaction using Pfu DNA polymerase, and Pfu DNA polymerase displays no significant changes of the secondary structure upon interaction with gold nanoparti...

Conjugation behaviours of CdTe quantum dots and antibody by a novel immunochromatographic method

IET Nanobiotechnology — Tue, 25 Jan 2011 14:47:56 +0100

Three water-soluble CdTe quantum dots (QDs) (green-emitting, yellow-emitting and red-emitting) were synthesised for different refluxing time with 3-mercaptopropionic acid (MPA) as stabiliser. Then the red-emitting CdTe QDs and mouse immunoglobulin G (IgG) were taken as the representative to study the conjugation behaviour of QDs and antibody by a novel immunochromatographic method. After comparing with several methods, that is, direct conjugation, 1-ethyl-3(3- dimethylaminopropyl) carbodiimides hydrochloride (EDC)-mediated conjugation, N-hydroxysuccinimide (NHS)-mediated conjugation, EDC/NHS-mediated conjugation by immunochromatographic strips, EDC and NHS were selected together as coupling agents to conjugate QDs with antibody efficiently. Finally, the K562 leukaemia cells were incubated ...

Scanning tunneling microscopy of cauliflower-like DNA nanostructures synthesised by loop-mediated isothermal amplification

IET Nanobiotechnology — Tue, 25 Jan 2011 14:47:55 +0100

DNA nanotechnology is a novel approach for synthesis of DNA-based nanostructures. Stem-loops, nanojunctions, sticky-ends and periodic lengths of DNA are the most essential nanostructures in DNA nanofabrications. Loop-mediated isothermal amplification (LAMP) is a powerful technology for repetitive synthesis of double-stranded and cauliflower-like DNAs. The process leads to long and repetitive sequences of DNAs, which are fabricated via loop primers. The authors demonstrate here scanning tunneling micrographs of LAMP-synthesised DNAs deposited on highly ordered pyrolytic graphite. The scans are compared with natural DNAs. Scanning tunneling microscopy (STM) images indicated the creation of periodic long DNAs, stem-looped DNAs and three-way DNA nanojunctions. It is also suggested that such na...

Dielectrophoretic tweezer for isolating and manipulating target cells

IET Nanobiotechnology — Tue, 25 Jan 2011 14:47:55 +0100

The ability to isolate and accurately position single cells in three dimensions is becoming increasingly important in many areas of biological research. The authors describe the design, theoretical modelling and testing of a novel dielectrophoretic (DEP) tweezer for picking out and relocating single target cells. The device is constructed using facilities available in most electrophysiology laboratories, without the requirement of sophisticated and expensive microfabrication technology, and offers improved practical features over previously reported DEP tweezer designs. The DEP tweezer has been tested using transfected HEI-193 human schwannoma cells, with visual identification of the target cells being aided by labelling the incorporated gene product with a green fluorescent protein. (Sour...

Effect of chitosan-polyvinyl alcohol blend nanofibrous web on the healing of excision and incision full thickness wounds

IET Nanobiotechnology — Sat, 09 Oct 2010 00:56:31 +0100

Chitosan-polyvinyl alcohol (PVA) blend nanofibrous webs were fabricated in different blend ratios through electrospinning procedures. From scanning electron microscopy (SEM) results, 25/75 blend ratio of chitosan-PVA was selected for biological studies. In vivo studies were carried out on the dorsum of rats of two types: longitudinal incisional wounds (n = 8 rats) and round excisional wounds (n = 8). Pathological study was done on the wounds to investigate the healing process. The histological study in wound healing indicated that the administration of chitosan nanofibrous web improved the wound healing, qualitatively and quantitatively. (Source: IET Nanobiotechnology)

Miniaturisation of a capillary electrophoresis microchip for the sensing of endocrine disruptors

IET Nanobiotechnology — Sat, 09 Oct 2010 00:56:28 +0100

Although capillary electrophoresis amperometric detector (CE-AD) involving double-T microchannel configuration is a powerful analytical tool in terms of sensitivity and selectivity, its long microchannel configuration hinders further miniaturisation. Therefore a twisted CE microchannel configuration was used in the present study to fabricate CE-AD devices for detection of endocrine disruptors. The analyte separation time varied slightly for the twisted microchannel structure, whereas the detector sensitivities were similar for the two configurations. The conventional indium tin oxide amperometric detector in the device with twisted microchannel configuration was later modified with Prussian blue to enhance the sensitivity of detection. (Source: IET Nanobiotechnology)

Integrated circuit-based instrumentation for microchip capillary electrophoresis

IET Nanobiotechnology — Tue, 31 Aug 2010 05:28:42 +0100

Although electrophoresis with laser-induced fluorescence (LIF) detection has tremendous potential in lab on chip-based point-of-care disease diagnostics, the wider use of microchip electrophoresis has been limited by the size and cost of the instrumentation. To address this challenge, the authors designed an integrated circuit (IC, i.e. a microelectronic chip, with total silicon area of (Source: IET Nanobiotechnology)

Terminating polyelectrolyte in multilayer films influences growth and morphology of adhering cells

IET Nanobiotechnology — Tue, 31 Aug 2010 05:28:42 +0100

Polyelectrolyte films of anionic poly(sodium 4-styrenesulphonate) (PSS) and cationic poly (allylamine hydrochloride) (PAH) were constructed using layer-by-layer assembly. The authors examined the cytocompatibility of these films for future use in nanobiotechnology applications. Cell lines HEK-293 and 3T3-L1 were cultured on these films and the initial attachment, adhesion, proliferation and cytotoxicity of the cells were measured using a propidium iodide assay. The morphology and spread of the cells were measured by phase-contrast microscopy. The actin cytoskeleton was observed using fluorescent microscopy. Neither the PAH-terminated nor the PSS-terminated polyelectrolyte films were cytotoxic. The PAH-terminated polyelectrolyte films improved the initial attachment and subsequent adhesion ...

Well-defined thermo-responsive polymeric nanocapsules by a one-pot method via surface-initiated atom transfer radical copolymerisation

IET Nanobiotechnology — Tue, 31 Aug 2010 05:28:41 +0100

The well-defined thermo-responsive polymeric nanocapsules were prepared by the one-pot approach via the surface-initiated atom transfer radical copolymerisation of N-isopropyl acrylamide (NIPAM) and N, N-methylenebisacylamide (MBA) from the silica nanoparticle templates after the silica templates were removed by hydrofluoric acid (HF). The diameter of the polymeric nanocapsules is in the range of 20ߝ40nm, characterised by transmission electron microscopy (TEM). The temperature-induced dimensional change of the thermo-responsive polymeric nanocapsules was investigated by dynamic light scattering (DLS) in aqueous solutions. The intelligent thermo-responsive polymeric nanocapsules are expected to be used for the controlled release of sensitive molecules, such as enzymes, proteins or DNA...

Nano-engineered living bacterial motors for active microfluidic mixing

IET Nanobiotechnology — Tue, 31 Aug 2010 05:28:39 +0100

Active micromixers with rotating elements are attractive microfluidic actuators in many applications because of their mixing ability at a short distance. However, miniaturising the impeller design poses technical challenges including the fabrication and driving means. As a possible solution inspired by macro magnetic barstirrers, this study proposes the use of tethered, rotating bacteria as mixing elements. A tethered cell is a genetically engineered, harmless Escherichia coli (E. coli) attached to a surface by a single, shortened flagellum. The tethered flagellum acts as a pivot around which the entire cell body smoothly rotates. Videomicroscopy, image analysis and computational fluid dynamics (CFD) are utilised to demonstrate a proof-of-concept for the micro mixing process. Flow visualis...

Hepatocyte growth factor incorporated chitosan nanoparticles differentiate murine bone marrow mesenchymal stem cell into hepatocytes in vitro

IET Nanobiotechnology — Tue, 31 Aug 2010 05:28:39 +0100

In conclusion, HGF released from the HGF-CNP can differentiate MSC into hepatocytes, and this novel technique could also be extended to deliver therapeutic proteins for a variety of tissue regeneration. (Source: IET Nanobiotechnology)

Optimal design of microgrooved channels with electrokinetic pumping for lab-on-achip applications

IET Nanobiotechnology — Mon, 31 May 2010 23:00:00 +0100

This study reports optimal design of a microchannel with a microgrooved configuration for conductive fluid transport with alternating current electrothermal actuations. Significant improvements in flowrate are achieved over the planar configurations without additional temperature rises. The frequency and temperature dependences of AC electrothermal (ET) flow are investigated and analysed. (Source: IET Nanobiotechnology)

Preparation of degradable polymeric nanocapsules from hyperbranched poly (amine ester) grafted nanosilica templates

IET Nanobiotechnology — Mon, 31 May 2010 23:00:00 +0100

A facile approach for the preparation of degradable crosslinked polymeric nanocapsules with hydroxyl functional groups was developed by polycondensation from the nanosilica templates. The hyperbranched poly (amine ester) grafted silica nanoparticles (SN-HPAE) were crosslinked with hexamethylene diisocyanate (HDI). Then the silica templates were removed by HF etching to produce the degradable polymeric nanocapsules. The inner diameter of polymeric nanocapsules is in the range of 20¿100 nm, which is characterised by transmission electron microscopy (TEM). The strategy developed was confirmed with Fourier transform infrared, thermogravimetric analysis and TEM. (Source: IET Nanobiotechnology)

Synthesis, stabilisation and characterisation of rhamnolipid-capped ZnS nanoparticles in aqueous medium

IET Nanobiotechnology — Mon, 31 May 2010 23:00:00 +0100

In this study, the authors used rhamnolipids for capping ZnS nanoparticles. The capped particles were stabilised in aqueous environment and its characteristics were studied using Fourier transform infrared spectroscopy (FT-IR), small angle X-ray scattering (SAXS), high resolution transmission electron microscopy (HR-TEM) and ultraviolet¿ visible spectra, fluorescence spectra. The particle Bohr radius was found to be 4.5 nm both by SAXS and HRTEM, thus proving rhamnolipid to be an effective capping agent for the synthesis of uniform nanoparticles. SAXS study not only reveals the particle size and distribution but also its self-affined agglomeration behaviour. This work is a novel method for stabilising nanoparticles in aqueous condition using biosurfactant. (Source: IET Nanobiotechnology)

Parallel growth and healing of DNA self-assembly for interconnects

IET Nanobiotechnology — Mon, 01 Mar 2010 00:00:00 +0100

This study proposes a diagonally based growth scheme that is applicable to these templates of interconnects (as an example). Differently from previous techniques (mostly sequential in execution), growth is allowed along two different directions in the aggregate, thus permitting a parallel mode of operation. This is made possible by utilising a tile set and binding scheme to allow multiple seed tiles to grow along the main diagonal of the pattern. The conditions by which this type of new growth is possible at a reduced error occurrence in mismatched tiles, are presented; error tolerance is achieved by employing healing and so-called robust generation of the seed tiles, thus ensuring that pattern growth is controlled along both directions. Simulation results are presented under different sce...

Coupled model analysis of the structure and nano-mechanical properties of dragonfly wings

IET Nanobiotechnology — Mon, 01 Mar 2010 00:00:00 +0100

To establish the quantitative model of the dragonfly wing the reconfiguration and nanoindentation technique were used. The mechanical properties of wings were measured by nanoindentre. Generally, the costa undertake is mainly pressure, and its mechanical properties should be the largest. However, in the nanoindentation test, the largest value of the reduced modulus (Er) and hardness (H) mainly appear in the radius, except the value at 0.7L (L is the wing length). The Er and H of the forewing were larger than that of the hindwing, except the value at 0.7L. The reversing engineering (3-D scanner) and AutoCAD were cooperated to reconfigure the dragonfly wing. Then the material parameters and skeleton transforms to a finite element analysis. The quantitative models were discussed in static ran...

Characterisation of protein adsorption on different liquid crystal phthalocyaninethin films

IET Nanobiotechnology — Mon, 01 Mar 2010 00:00:00 +0100

Bovine serum albumin (BSA) protein adsorption on thin spun films of different metal octakishexylthiophthalocyanine [(C6S)8PcM, M=Cu, Ni] derivatives is investigated by using three independent spectroscopic measurements namely Raman spectroscopy, ellipsometry and surface plasmon resonance imaging. Thermally induced molecular self-reorganisations in the phthalocyanine films are found to have produced the changes in the surface energy which, in turn, control protein adsorption. The amount of BSA adsorption on [(C6S)8PcNi] is more limited than that on [(C6S)8PcCu] and this observation is consistent with the results on the surface wettability obtained from the contact angle measurements. The shift from the plasmonic resonance wavelength because of the BSA adsorption was significantly larger for...

Effects of poly (lactic-co-glycolic acid) as a co-emulsifier on the preparation and hypoglycaemic activity of insulin-loaded solid lipid nanoparticles

IET Nanobiotechnology — Thu, 19 Nov 2009 16:37:47 +0100

Poly (lactic-co-glycolic acid) (PLGA) was used as a co-emulsifier in the preparation of insulin-loaded solid lipid nanoparticles (SLN) with hydrogenated castor oil as lipid matrix and lecithin as surfactant by doubleemulsion technique. The effects of PLGA on the preparation and hypoglycaemic activity of insulin-loaded SLN were studied. The results showed that with the supplement of PLGA, the encapsulation efficiency and loading capacity were increased significantly from 79.08±1.62 to 85.57±3.21% and 1.58±0.03 to 1.71±0.06%, whereas the surface charge and particle size were changed insignificantly from -25.87±2.65 to -22.67±1.19 mv and 431.0±16.1 to 397.0±68.0 nm, respectively. In vivo studies demonstrated that PLGA increased t...

Performance analysis and comparison of a minimum interconnections direct storage model with traditional neural bidirectional memories

IET Nanobiotechnology — Thu, 19 Nov 2009 16:37:47 +0100

This study proposes an efficient and improved model of a direct storage bidirectional memory, improved bidirectional associative memory (IBAM), and emphasises the use of nanotechnology for efficient implementation of such large-scale neural network structures at a considerable lower cost reduced complexity, and less area required for implementation. This memory model directly stores the X and Y associated sets of M bipolar binary vectors in the form of (M X Nx) and (M X Ny) memory matrices, requires O(N ) or about 30% of interconnections with weight strength ranging between ±1, and is computationally very efficient as compared to sequential, intraconnected and other bidirectional associative memory (BAM) models of outer-product type that require O(N 2) complex interconnections with...

Surface plasmon resonance imaging for biosensing

IET Nanobiotechnology — Sat, 08 Aug 2009 12:28:45 +0100

Surface plasmon resonance imaging (SPRI) is a useful tool for the study of surface biomolecular interactions allowing for label-free detection and elegant instrumentation. SPRI imaging system is described in this review with an emphasis on recent applications with examples of different biological interactions and high throughput analysis. Signal amplification in SPRI using nanoparticle and waveguide-based optical coupling is introduced. Finally the detection sensitivity of the SPRI system is examined in terms of other competitive methods. (Source: IET Nanobiotechnology)

Nanoreactors for pH controlled sequential activity switching in multistep enzymatic processes

IET Nanobiotechnology — Sat, 08 Aug 2009 12:28:45 +0100

This theoretical model predicts that the activity of multiple enzymes may be controlled simultaneously with superior efficiency in nanosized reactors by adjusting pH. Multistep enzymatic processes employed for various purposes including organic biotransformation may require application of multiple reactions and isolation of intermediates. Sequential activity switching would offer substantial advantages. Nanoreactors would provide better option to fully appreciate the pH switching approach. (Source: IET Nanobiotechnology)

Dynamics of capturing process of multiple magnetic nanoparticles in a flow through microfluidic bioseparation system

IET Nanobiotechnology — Sat, 08 Aug 2009 12:28:42 +0100

A mathematical model based on finite-element technique is developed for predicting the transport and capture of multiple magnetic nanoparticles in a microfluidic system that consists of a microfluidic channel enclosed by a permanent magnet. The trajectories and trapping efficiencies are calculated for multiple magnetic nanoparticles when released in the microsystem. It is demonstrated that not only the size but also the point of release of nanoparticles within the microchannel affects the capturing process. Influence of three important parameters, inlet velocities of fluid containing magnetic nanoparticles, diameter of magnetic nanoparticles and magnetic field strength on the trapping efficiency are investigated and optimised values of inlet velocity and magnetic field strength for complet...

Localised heating of tumours utilising injectable magnetic nanoparticles for hyperthermia cancer therapy

IET Nanobiotechnology — Sun, 31 May 2009 23:00:00 +0100

This study reports an investigation of hyperthermia cancer therapy utilising an alternating magnetic field to induce a localised temperature increase on tumours by using injectable magnetic nanoparticles. Invitro and in-vivo experiments represent the feasibility of hyperthermia cancer therapy. A feedback temperature control system was first developed to keep the nanoparticles at a constant temperature to prevent overheating in the tumours such that a safer and more precise cancer therapy becomes feasible. By using the feedback temperature control system, magnetic nanoparticles can be heated up to the specific constant temperatures, 37, 40, 42, 45, 46 and 47°C, respectively, with a variation less than 0.2°C. With this approach, the in-vitro survival rate of tumour cells at d...

Dielectric and dielectrophoretic properties of DNA

IET Nanobiotechnology — Sun, 31 May 2009 23:00:00 +0100

The physical properties of DNA are quite important for molecular genetics as well as for its nanotechnological applications. Studying the interactions of alternating current (AC) electric fields with deoxyribonucleic acid (DNA) allows one to draw conclusions about these properties. These interactions are usually investigated in two different ways. In dielectric spectroscopy, a DNA solution is placed in a homogeneous AC field and electronic parameters are measured over several frequency decades in the Hz to GHz range. These electronic data are then interpreted on the basis of physico-chemical models as a result of certain phenomena on the molecular level. In dielectrophoretic studies, a DNA solution is exposed to an inhomogeneous AC field and the spatial response of few or single molecules ...

Preparation of carboxyl-coated polystyrene nanoparticles using oleic acid

IET Nanobiotechnology — Sun, 31 May 2009 23:00:00 +0100

Novel carboxyl group-decorated crosslinked polystyrene nanoparticles were prepared via the soapless emulsion polymerisation of styrene and divinyl benzene with oleic acid as functional comonomer. The existence of the surface carboxyl group was verified by zeta potential analysis. Particle sizes of the functional nanoparticles prepared with the proposed method were found to be in the range of 60¿100 nm by transmission electron microscopy and dynamic light scattering analyses. Functionalised nanoparticles are proposed as carriers for biomolecules or drugs. (Source: IET Nanobiotechnology)

Bacterial detection using a carbon nanotube gas sensor coupled with a microheater for ammonia synthesis by aerobic oxidisation of organic components

IET Nanobiotechnology — Sun, 31 May 2009 23:00:00 +0100

In this study, the authors propose a new bacteria detection method using a carbon nanotube (CNT) gas sensor and a microheater, which were coupled into a Bio-MEMS (microelectromechanical systems)-type device. Bacteria were heated by the microheater in air so that ammonia (NH3) gas can be generated by the oxidation reaction of organic components of bacteria. Thus generated NH3 gas was detected by using the CNT gas sensor, which was fabricated by dielectrophoresis (DEP) and combined with the microheater to form a small chamber. Cyclic pulsed heating operation was employed so that the CNT response to elevated temperature did not mask NH3 response. It was demonstrated that the proposed device could detect and quantify 107 bacteria cells (Escherichia coli). Possible application of DEP to trap an...

Preparation, structure and drug release behaviour of chitosan-based nanofibres

IET Nanobiotechnology — Sat, 14 Mar 2009 04:00:00 +0100

Biomimetic polymeric nanofibres are of great interest in tissue engineering and wound repair because of their structural similarity to extracellular matrix. In this work, biomimetic chitosan-based nanofibres with various diameters were prepared by ionically cross-linking with tripolyphosphate (TPP) in adipic acid medium and characterised using transmission electron microscopy, X-ray diffraction and Fourier-transform infrared spectroscopy. Using dexamethasone sodium phosphate (DMP) and bovine serum albumin (BSA) as low and high molecular-weight bioactive molecule models, respectively, drug loading and in vitro release behaviours of chitosan-TPP nanofibres were investigated. The drug-loaded chitosan-TPP nanofibres showed a prolonged release profile with three distinct stages in physiological...

Inexpensive, universal serial bus-powered and fully portable lab-on-a-chip-based capillary electrophoresis instrument

IET Nanobiotechnology — Sat, 14 Mar 2009 04:00:00 +0100

Capillary electrophoresis is a cornerstone of lab-on-a-chip (LOC) implementations for medical diagnostics. However, the infrastructure needed to operate electrophoretic LOC implementations tends to be large and expensive, hindering the development of portable or low-cost systems. A custom-designed and highly integrated microelectronic chip for high-voltage generation switching and interfacing is recently developed. Here, the authors integrate the microelectronic chip with a microfluidic chip, a solid-state laser, filter, lens and several dollars worth of electronic components to form an inexpensive and portable platform, which is the size of a mobile telephone. This compact system has such reduced power requirements that the complete platform can be operated using a universal serial bus li...

High-yield electrofusion of biological cells based on field tailoring by microfabricated structures

IET Nanobiotechnology — Fri, 21 Nov 2008 14:35:39 +0100

The authors present the use of electric-field constriction created by a microfabricated structure to realise high-yield electrofusion of biological cells. The method uses an orifice on an electrically insulating wall (orifice plate) whose diameter is as small as that of the cells. Owing to the field constriction created by the orifice, we can induce the controlled magnitude of membrane voltage selectively around the contact point, regardless of the cell size. The field constriction also ensures 1:1 fusion even when more than two cells are forming a chain at the orifice. A device for electrofusion has been made with a standard SU-8 lithography and PDMS molding, and real-time observation of the electrofusion process is made. Experiments using plant protoplasts or mammalian cells show that th...

Healing assessment of tile sets for error tolerance in DNA self-assembly

IET Nanobiotechnology — Fri, 21 Nov 2008 14:35:38 +0100

An assessment of the effectiveness of healing for error tolerance in DNA self-assembly tile sets for algorithmic/nano-manufacturing applications is presented. Initially, the conditions for correct binding of a tile to an existing aggregate are analysed using a Markovian approach; based on this analysis, it is proved that correct aggregation (as identified with a so-called ideal tile set) is not always met for the existing tile sets for nano-manufacturing. A metric for assessing tile sets for healing by utilising punctures is proposed. Tile sets are investigated and assessed with respect to features such as error (mismatched tile) movement, punctured area and bond types. Subsequently, it is shown that the proposed metric can comprehensively assess the healing effectiveness of a puncture typ...

Implementation of wireless power transfer and communications for an implantable ocular drug delivery system

IET Nanobiotechnology — Sat, 25 Oct 2008 14:28:04 +0100

A wireless power transfer and communication system based on near-field inductive coupling has been designed and implemented. The feasibility of using such a system to remotely control drug release from an implantable drug delivery system is addressed. The architecture of the wireless system is described and the signal attenuation over distance in both water and phosphate buffered saline is studied. Additionally, the health risk due to exposure to radio frequency (RF) radiation is examined using a biological model. The experimental results demonstrate that the system can trigger the release of drug within 5 s, and that such short exposure to RF radiation does not produce any significant ( les1degC) heating in the biological model. The conclusion of the work is that this system could replace...

Polarisation and membrane voltage of ellipsoidal particle with a constant membrane thickness: a series expansion approach

IET Nanobiotechnology — Sat, 25 Oct 2008 14:28:04 +0100

The estimation of the membrane voltage and the polarisation factor of biological cells provide a base for the study of bio-manipulation techniques, such as dielectrophoresis, electroporation or electrofusion. To model a biological cell, an ellipsoidal particle with an insulating membrane is sometimes employed, but due to the limitation of the confocal nature of the coordinate system, the membrane thickness is assumed to vary with the position, despite the fact that the lipid bilayer membrane has a uniform thickness. The authors present a method to rigorously treat the uniform-thickness condition in a system having an axial symmetry. The method is based on the harmonic expansion of the field, to include the condition of the uniform- membrane thickness as a series expansion of the geometrica...

Nanoelectronic interface for lab-on-a-chip devices

IET Nanobiotechnology — Sat, 25 Oct 2008 14:28:04 +0100

Innovations in microfabricated analytical devices integrated with microelectronic circuits and biological cells show promising results in detection, diagnosis and analysis. Planar metallic microelectrodes are widely used for the electrical interface with the biological cells. Issues with the current microelectrode array design are the difficulty in selective integration with a cell, the size dependency of its impedance and the large amount of noise in the circuit due to this mismatch. It is quite evident that an approach utilising nanotechnology can solve some of these problems by yielding efficient electrical interconnections. The design and development of a planar microelectrode array integrated with vertically aligned nanowires for lab-on-a- chip (LoC) device applications are presented....

Fluorescent resonance energy transfer based detection of biological contaminants through hybrid quantum dot-quencher interactions

IET Nanobiotechnology — Tue, 10 Jun 2008 04:00:00 +0100

A nanoscale sensor employing fluorescent resonance energy transfer interactions between fluorescent quantum dots (QDs) and organic quencher molecules can be used for the multiplexed detection of biological antigens in solution. Detection occurs when the antigens to be detected displace quencher-labelled inactivated (or dead) antigens of the same type attached to QD-antibody complexes through equilibrium reactions. This unquenches the QDs, allowing detection to take place through the observation of photoluminescence in solution or through the fluorescence imaging of unquenched QD complexes trapped on filter surfaces. Multiplexing can be accomplished by using several different sizes of QDs, with each size QD labelled with an antibody for a different antigen, providing the ability to detect s...

Enhanced bio-molecular interactions through recirculating microflows

IET Nanobiotechnology — Tue, 10 Jun 2008 04:00:00 +0100

A recirculating microfluidic platform has been developed for carrying out optical bio-detection. The present device can be used for passive mixing of the biological species with the microfluidic channel without immobilisation, through appropriate design and flow control. The feasibility of bio-detection using the present setup has been demonstrated through the method of fluorescence and the experiments were carried out with Antisheep Antibody (AB) tagged with Alexafluor 647 (AF647) fluorophore particles. By controlling the fluid flow, it was possible to isolate AB separately into a recirculation zone within the microfluidic channel, thereby enabling qualitative and quantitative bio-detection. Finite element modelling of the flow behaviour has been carried out and the results were similar t...

Dielectrophoretic assembly of insulinoma cells and fluorescent nanosensors into threedimensional pseudo-islet constructs

IET Nanobiotechnology — Tue, 10 Jun 2008 04:00:00 +0100

Dielectrophoretic forces, generated by radio-frequency voltages applied to micromachined, transparent, indium tin oxide electrodes, have been used to condense suspensions of insulinoma cells (BETA-TC-6 and INS-1) into a 10times10 array of three-dimensional cell constructs. Some of these constructs, measuring ~150 mum in diameter, 120 mum in height and containing around 1000 cells, were of the same size and cell density as a typical islet of Langerhans. With the dielectrophoretic force maintained, these engineered cell constructs were able to withstand mechanical shock and fluid flow forces. Reproducibility of the process required knowledge of cellular dielectric properties, in terms of membrane capacitance and membrane conductance, which were obtained by electrorotation measurements. The a...

Interactions of electrical fields with fluids:laboratory-on-a-chip applications

IET Nanobiotechnology — Mon, 03 Mar 2008 05:00:00 +0100

(Source: IET Nanobiotechnology)

Recent advances in microparticle continuous separation

IET Nanobiotechnology — Mon, 03 Mar 2008 05:00:00 +0100

(Source: IET Nanobiotechnology)