Abstract:Fast, efficient and accurate molecular biological detection is very important in pathogen detection. Nucleic acid extraction is the basis of molecular detection. At present, the commonly used magnetic bead method, which takes many operating steps, is time-consuming and inconvenient for rapid detection on site. Microfluidic technology has the characteristics of rapidness, integration and miniaturization, which can provide an effective platform for rapid nucleic acid extraction and rapid detection. Based on the magnetic bead nucleic acid extraction method in the principle of solid phase extraction, a microfluidic chip for DNA extraction from various food-borne pathogens was designed. The chip mainly included a lysis chamber, a cleaning chamber, an elution chamber, a suction hole, a vent, a pneumatic valve, a capillary valve and other accessories, which could complete operations such as the extraction and purification of nucleic acid and the sequential loading of food-borne pathogens. In order to increase the concentration of nucleic acid extraction, the hydrophilization treatment of chip channel, the incubation time, magnetic bead mixing times and elution time during extraction process were optimized. The results showed that the best incubation time on the chip was 9 min, the best mixing times was 9 times, and the best elution time was 20 min. The nucleic acid concentration of ，Escherichia coli, Salmonella and Listeria monocytogenes extracted on the chip was high and could be used for PCR amplification and gel electrophoresis detection. This method has the advantages of low reagent consumption and low probability of contamination, and could be used for preparation of integrated chip for nucleic acid extraction and amplification.
