Study On Enrichment Of Escherichia Coli And Detection Performance In A Microfluidic Chip

Respiratory pathogenic microorganisms(RPMs)have great harm to human health in history.Although a variety of techniques had been developed to detect pathogenic microorganisms in the air,there are some drawbacks,including time-consuming,manpower needed,hindered a rapid and effective detect based on existing detection systems,which leads to a high death rate and morbidity related to respiratory diseases.To develop simple and accurate sensor systems for detection of various RPMs,some novel sensors,for example microfluidic chips,have drawn more and more attentions in field of detection of RPMs.Microfluidic technology is a cross-domain innovation that integrating analytical chemistry,micro-electromechanical processing,biology,and nanotechnology to manipulate nano-liter fluid in a tiny micro channel.Microfluidic chip system has attracted much attention because of its simple operation,low cost,small volume,high throughput and low dosage.At present,microfluidic chip detection technology has been gradually applied to a variety of pathogenic microorganisms and environmental monitoring,and greatly promoting the continuous development of microfluidic technology with the development and integration of the most advanced technology in multiply disciplines.This study aims to provide a reutilization microfluidic chip for the enrichment,detection and quantification of E coli,realizing the quickness and simplicity in practical application.In this experiment,a new type of synthetic hydrogel P(PEGDA/DMAEMA)was used as substrate material of the chip,to obtained the optimal hydrophily by orthogonal test the optimum combination ratio of PEGDA: DMAEMA = 4: 6 + 10NVP%.Two microfluidic chips were rapidly prepared under a UV lamp,supplemented with masks.After the preparation of the chip,E.coli was used as the model organism to verify the enrichment efficiency of two structures.The results showed that the chip could enrich and culture E.coli in the air,and the dentate-shape chip could attain the highest enrichment efficiency of 96.8% in 30 minutes,and the proliferation rate was significantly higher than traditional plate culture method.The main reason of the high enrichment rate of the chip is analyzed by the digital simulation of the velocity field,the pressure field distribution and the particle size tracking.Eventually,the color medium on the microfluidic chip was applied to rapid quantitative of the enriched Escherichia coli.The results show that the chip can be used to identify the strains and initial concentration by color and chromogenic reaction time directly.The detection limit and sensitivity are obviously superior to the traditional method,Showing a good application prospects.