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Cuvette-based microfluidic device integrated with nanostructures for measuring dual Localized Surface Plasmon Resonance (LSPR) signals
摘要： A spectrophotometer that uses a localized surface plasmon resonance phenomenon is a powerful measurement tool in the biotechnology and bioanalysis fields. We propose a novel cuvette design type that can be used for universal spectrophotometers. The novel cuvette design needs a few μl reagent for measuring, and also two chips for measurement can be loaded and measured at the same time. A new cuvette can easily be used several times because of sample chips to be loaded and unloaded since they are mechanically mounted by screws. Therefore, it can offer advantages to users in terms of cost and time. We verify its possibility for use in the biotechnology and bioanalysis fields by a signal enhancement and dual signal detection.
关键词： spectrophotometer,bioanalysis,nanostructures,microfluidic device,biotechnology,Localized Surface Plasmon Resonance,LSPR
更新于2025-09-23 15:21:01
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[American Society of Agricultural and Biological Engineers 2017 Spokane, Washington July 16 - July 19, 2017 - ()] 2017 Spokane, Washington July 16 - July 19, 2017 - <i>Rapid and reliable norovirus assay at pg/mL level using smartphone-based fluorescence microscope and a microfluidic paper analytic device</i>
摘要： Detection of norovirus from water samples typically requires extremely low limit of detection (LOD), preferably at single virus particle level, since they can be pathogenic at extremely low concentrations. Complicated equipment and/or lengthy procedures are necessary to concentrate large volume of water sample. In addition, this low LOD requirement have traditionally been associated non-reproducible and less convincing assay results. In this work, rapid and reliable detection of norovirus contamination in water samples was demonstrated using an in-house developed smartphone-based fluorescence microscope and a paper microfluidic analytic device (μPAD). Norovirus was concentrated directly on the μPAD, which was fabricated with polarity filter, to further decrease the LOD. Antibody-conjugated submicron (0.5 μm diameter) fluorescent particles were added to this μPAD, and a smartphone based fluorescence microscope imaged these beads directly from the μPAD. Since the spatial resolution of our smartphone-based fluorescence microscope is > 1 μm, only the beads immunoaggltuinated by norovirus can be identified, providing reliable, reproducible, and visually convincing assay results. Using this novel this method, extremely low LOD was demonstrated, 0.01 pg/mL with a benchtop fluorescence microscope and 10 pg/mL to 100 pg/mL with a smartphone based fluorescence microscope. This novel assay can provide a fully unmanned platform for assaying various waterborne pathogens that require extremely low LOD as well as high reliability, while providing low-cost, ease-of-use, and user friendliness appropriate for field applications.
关键词： μPAD,fluorescence microscope,waterborne pathogen,immunoagglutination,microfluidic device
更新于2025-09-23 15:21:01
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Improved electrical performance and transparency of bottom-gate, bottom-contact single-walled carbon nanotube transistors using graphene source/drain electrodes
摘要： We propose a centrifuge-based microfluidic device housed in a standard microtube for generation of monodisperse microdroplets from tens of μl sample volume. Centrifugation drives overpressure of a dispersed phase, thus infuses the dispersed phase into a microchannel. Because of the channel geometry for step emulsification, the infused dispersed phase is pinched off forming droplets. Then, the droplets accumulate on the bottom of the microtube by centrifugal force. We succeeded in generation of monodisperse droplets with a diameter of 130 μm (CV <2%) by operation of centrifuge. Since the device can produce droplets in a microtube without complex experimental setup (e.g. syringe pump), it will be a powerful tool for simple generation of droplets for droplet-based applications.
关键词： centrifuge-based,microfluidic device,monodisperse droplets,step emulsification
更新于2025-09-12 10:27:22
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Photothermal Microfluidic Sensing Platform Using Near-Infrared Laser-Driven Multiplexed Dual-Mode Visual Quantitative Readout
摘要： The application of different sensing principles in microfluidic devices opens up further possibilities for the development of point-of-care testing (POCT). Herein, the photothermal sensing principle is introduced in microfluidic paper-based analytical devices (μPADs) to develop a photothermal microfluidic sensing platform using near-infrared (NIR) laser-driven multiplexed dual-mode visual quantitative readout. Prussian blue (PB) as the analyte-associated photothermal agent was in-situ synthesized in thermoresponsive poly(N-isopropylacrylamide) hydrogels to serve as the on-chip photothermal sensing element. NIR laser-driven photothermal effect of PB triggered not only on-chip dose-dependent heat generation but also phase transition-induced dye release from the hydrogels, simultaneously enabling both thermal image- and distance-based dual-mode visual quantitative readout of the analyte concentration in a multiplexed manner. Both the on-chip temperature elevation value of the hydrogels and the traveling distance of released dye solutions were proportional to the concentration of PB. Using the detection of silver ions in environmental water as a proof-of-concept study, the photothermal μPAD can detect silver ions at a concentration as low as 0.25 μM with high selectivity and satisfactory accuracy. The photothermal microfluidic sensing platform holds great potential for POCT with promising integratability and broad applicability, owing to the combination of synergistic advantages of the photothermal sensing principle, μPADs and photothermally responsive hydrogels.
关键词： Microfluidic device,Photothermal effect,Visual readout,Point-of-care testing,Thermoresponsive hydrogel
更新于2025-09-11 14:15:04