| Summary: | 碩士 === 國立聯合大學 === 化學工程學系碩士班 === 106 === In recent years, the food adulteration has been discovered one after another, arousing public's attention and causing doubt on food safety. Although the traditional analysis methods such as high performance liquid chromatography, gas chromatography, and capillary electrophoresis have high detection sensitivity, those instruments are expensive and take much space. Consequently, in this study, we combined genetic detection for polymerase chain reaction (PCR) and with the microfluidic chip having advantages such as reducing the amount of the sample and reaction reagent, miniaturization device, rapid analysis, and simple operation. We constructed a PCR microfluidic chip detection platform, including a poly(dimethylsiloxane) (PDMS) microfluidic chip, a temperature-controlled heating device, and a fluorescence microscope system. Droplet-based microfluidics used two immiscible liquids that mineral oil as the continuous phase and PCR reagents as the dispersed phase, and then we utilized cross-flow microchannels to generate monodispersed PCR droplets to avoid the vaporization of PCR reaction reagent. We performed an experiment on this system by weighing method and found that PCR droplets in the chip can reduce the evaporation of the PCR reaction reagent by 7.103% compared to the PCR reaction reagent directly injected into the chip, by preventing the air bubbles generation, and stabilized the flow sequence. The platform with droplet-based PCR microfluidic chip of 100 μm cross-flow channel carried out the PCR process and successfully amplified the target genes for sesame 146 bp, peanut 181 bp, Salmonella 237 bp, and Staphylococcus aureus 406 bp. Besides, we specifically selected the peanuts PCR experiment for droplet-based PCR microfluidic chip of 200 µm cross-flow microchannel under surface treatment with SigmaCote. This method could speed overall PCR reaction time. We observed a thermocycle time in PCR reduced from 18 s in the 100 µm crossflow microchannel to 13 s in the 200 µm cross-flow microchannel. The electrophoresis detection verified PCR amplification, and the fluorescence microscopy system also successfully detected the peanut PCR amplification product of the SYBR Green PCR reagent. As a result, the platform established in this study can achieve the purpose of rapid detection and improve the PCR reaction efficiency.
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