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Nanobiotechnology, IET

Issue 2 • Date June 2008

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Displaying Results 1 - 3 of 3
  • Dielectrophoretic assembly of insulinoma cells and fluorescent nanosensors into threedimensional pseudo-islet constructs

    Page(s): 31 - 38
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (660 KB)  

    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 ability to incorporate fluorescent nanosensors, as probes of cellular oxygen and pH levels, into these 'pseudo-islets' was also demonstrated. The footprint of the 10times10 array of cell constructs was compatible with that of a 1536 microtitre plate, and thus amenable to optical interrogation using automated plate reading equipment. View full abstract»

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  • Enhanced bio-molecular interactions through recirculating microflows

    Page(s): 39 - 46
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (561 KB)  

    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 to the results of flow visualisation obtained with tagged antibody particles. The present work thus provides confidence in using the hybrid integrated device for in situ rapid biomedical detection of biological pairs or individual specimen in fluorescence-based chemical and biological sensing. View full abstract»

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

    Page(s): 47 - 53
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (323 KB)  

    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 several types of antigens or biological contaminants simultaneously in near real-time with high specificity and sensitivity. View full abstract»

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Aims & Scope

IET Nanobiotechnology covers all aspects of research and emerging technologies including fundamental theories and concepts applied to biomedical-related devices and methods at the micro- and nano-scale.

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