The Design,Fabricating And Application In Pathogen Detection Of Self-driving Microfluidic Chip

The rapid development of microfluidic chip can promote the miniaturization of pathogen detection system.The fabrication of microchannel on microfluidic chip relies on photochemical etching and laser processing.However,there are difficulty in chemical reagent recovery and low processing efficiency,respectively.Meanwhile,it is difficult for surface control in both microchannel processing.Hence,the precision and smooth grinding of the quartz glass microchannel was proposed on the precision grinding machine with diamond grinding wheel micro-tip that was developed before,and then the die core of microchannel was developed to facing industry and achieving hot embossing forming of PMMA microchannel chip,and applying in the rapid detection of pathogens.First,the microchannel structure of the microfluidic chip were designed and processed on the PMMA and the quartz glass substrate,and developing the negative pressure self-driving microfluidic chip for the detection of the pathogen.Then,the processed substrate was bonding with the PET film,and the optimum bonding parameters for the optical glass microfluidic chip were obtained by experimental analysis.Then,the microfluid self-driving speed was analyzed with the tip angle,gradient,roughness of the wall and chip material of microchannel with experiment,and the model of microfluid flowing induced by the micro-/nanoscale structure in microfluidic chip was established.Finally,the result for rapid detection of pathogens was analysis with using the self-driving microfluidic chip.The conclusions of this study are as follows:1.The PMMA and quartz glass microchannels could process by microgrinding,the surface roughness could reach 28 nm and 42.8 nm respectively,and the angle error is up to 0.5° and 1° respectively.Furthermore,the hot embossing forming of PMMA microchannel was developed by using the die core of microchannel,and the forming time could reach 1?5 s.2.The bonding method based on PET film and hot embossing bonding can ensure the precision and the shape of the microfluidic channel.The study found that:the best pressure,time and temperature for the hot embossing bonding are 3.6 N,10 min and 650 ?.Furthermore,microfluidic chip with negative pressure and capillary force were developed,and the bonding had great applicability and flexibility.3.The microchannel tip angle and micro-/nanometer-scale crack distributed on the microchannel tip induces the self-driving of microfluid,and the self-driving speed may be increased by 20%when the microchannel tip angle is decreased to 60° from 120°,these micro-/nanometer-scale crack induction improves the self-driving speed by 27%.Meanwhile,compared with the microchannel without any gradient,the microchannel gradient of 0.43°may improve the self-driving speed by 121%and the flowrate by 254%,respectively.4.The designed and ground self-driving microfluidic chip can drive the pathogen nucleic acid solution to quickly mixing with the detection reagents.Through repeated experiments,the rapid detection of Campylobacter jejuni,Brucella,and Yersinia enteritis was achieved,and the process has high specificity,simple operation and less time-consuming.