128 research outputs found

    Nanomedicine enabled by computational sciences

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    Why not just switch on the light?: light and its versatile applications in the field of nanomedicine

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    Over the last decade, the emerging field of nanomedicine has undergone rapid progresses. Different internal and external stimuli like pH, temperature, radiation, ultrasound or light have been introduced to expand the diagnostic and therapeutic options of various applications within the field. This review focuses on the novel application of light in the field of nanomedicine as a mechanism to control drug delivery, release and biochemical and genetic functionality at the target. The field of functional nanomaterials for medicine, and in particular of light responsive nanocarriers, polymers and biomolecules offer new therapeutic options but also requires substantial further research to render this approach broadly applicable in clinical practic

    Screening cell surface receptors using micromosaic immunoassays

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    This report presents a general method for screening cell surface receptors using so-called micromosaic immunoassays. This method employs a microfluidic chip having n (n = 11) independent flow paths to move cells over m (m = 11) lines of surface-patterned antibodies for screening individual cells in a parallel, combinatorial, fast and flexible manner. The antibodies are patterned as 30-Ī¼m-wide lines on a poly(dimethylsiloxane) layer used to seal the area of the chip in which screening is being monitored. Mouse hybridoma cells having CD44 cell surface receptors and anti-CD44 antibodies were used to establish a proof-of-concept for this method. Both the capture antibodies and the cells were fluorescently labelled to allow the position of the cells to be accurately tracked over the binding sites using an inverted fluorescence microscope. The chips and cells were maintained at a constant temperature between 20 to 37Ā°C, and flow velocities of the cells over the capture areas were 100-280 Ī¼m~sāˆ’1, resulting in a āˆ¼0.1-0.3 s residency time of the cells on each of the eleven 30 Ɨ 30 Ī¼m s2 capture areas. Binding of the cells appeared to be specific to the capture areas, with a yield of 30% when the assay was performed at a temperature of 37Ā°C and with a slow flow velocity. We suggest that this proof-of-concept is broadly applicable to the screening of cells for medical/diagnostic purposes as well as for basic research on the interaction of cells with surface

    Modeling and Optimization of High-Sensitivity, Low-Volume Microfluidic-Based Surface Immunoassays

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    Microfluidics are emerging as a promising technology for miniaturizing biological assays for applications in diagnostics and research in life sciences because they enable the parallel analysis of multiple analytes with economy of samples and in short time. We have previously developed microfluidic networks for surface immunoassays where antibodies that are immobilized on one wall of a microchannel capture analytes flowing in the microchannel. This technology is capable of detecting analytes with picomolar sensitivity and from sub-microliter volume of sample within 45 min. This paper presents the theoretical modeling of these immunoassays where a finite difference algorithm is applied to delineate the role of the transport of analyte molecules in the microchannel (convection and diffusion), the kinetics of binding between the analyte and the capture antibodies, and the surface density of the capture antibody on the assay. The model shows that assays can be greatly optimized by varying the flow velocity of the solution of analyte in the microchannels. The model also shows how much the analyte-antibody binding constant and the surface density of the capture antibodies influence the performance of the assay. We then derive strategies to optimize assays toward maximal sensitivity, minimal sample volume requirement or fast performance, which we think will allow further development of microfluidic networks for immunoassay application
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