Summary: | 碩士 === 國立交通大學 === 機械工程學系 === 101 === This research describes a new method to integrate electrowetting on dielectric, dielectrophoresis and bead-based ELISA into a microfluidic chip with innovative 3-phase spiral electrodes. A single droplet containing randomly dispersed polystyrene microbeads conjugated with fluorescent dye is first moved by electrowetting to 3-phase spiral electrodes. The fluorescent microbeads are then concentrated by DEP force at 145 VRMS over 100 kHz. It is shown that the proposed microfluidic chip can evidently enhance the fluorescent intensity even there are only very few fluorescent microbeads (10 to 100) in a droplet whose volume is only 6.25 nL. The total operation time of the concentrating process is less than 3 min and the results are captured by inverted fluorescence microscope and are analyzed by image analysis software. The fluorescence intensity is enhanced evidently after concentrating fluorescent microbeads from the experiment data.
IL-18 is determined to be a sample in bead-based ELISA. The process is described as follows; first of all, IL-18 is immobilezed on streptavidin microbead by using biotin anti IL-18 rat IgG and then, IL-18 rabbit IgG and anti rabbit goat IgG conjugated with PE are added sequentially in order to conjugate fluorescent dye with IL-18. Finally, these fluorescent microbeads are used in above microfluidic chip for concentrating. In addition, the usage of EWOD will decrease the sample consumption and control the numbers of concentrated microbeads. In this research, fluorescent microbeads will be concentrated in a 6.25 nanoliter droplet within 3 minutes.
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