Research On Multi-Target Pathogenic Microorganism Immunoassay Based On CdSe/ZnS Quantum Dots And Quantum Dot Microspheres

Yersinia pestis,Escherichia coli O157:H7 and Salmonella paratyphi B are pathogenic microorganisms that pose a serious threat to human health and safety.Therefore,rapid and efficient detection methods are crucial for the early detection of these pathogens.The lateral flow immunoassay(LFIA)is an excellent method for rapid detection,but its detection accuracy and quantitative ability need to be improved.In this study,CdSe/ZnS quantum dots and CdSe/ZnS quantum dot microspheres were used as fluorescent labels in LFIA to optimize and evaluate the single-target LFIA for Yersinia pestis,Escherichia coli O157:H7 and Salmonella paratyphi B.Based on this,a multi-target LFIA was developed using a ten-channel array to achieve rapid quantitative detection of multiple pathogenic microorganisms.The main research results are as follows:1.CdSe/ZnS quantum dots and CdSe/ZnS quantum dot microspheres prepared by hot injection and microemulsion polymerization methods have excellent fluorescence intensity and uniform size distribution.2.The single-target flow-through immunochromatographic detection card using the two types of fluorescent markers showed the following detection performance for Yersinia pestis,Escherichia coli O157:H7 and Salmonella paratyphi B:(1)The detection accuracy with a CV below 15%and a linear fit curve with an R~2above 90%showed the excellent quantitative detection ability of the flow-through immunochromatographic detection card.(2)Excellent detection performance at a detection concentration of 10~3 CFU/m L,with even smaller quantum dot labeled items(Yersinia pestis and Escherichia coli O157:H7)being effectively detected at a concentration of up to 10~2 CFU/m L.(3)Quantum dot microspheres with higher fluorescence intensity of single particle showed better detection gradient.(4)In the specificity evaluation of quantum dot labeling,it exhibited good detection specificity for 15 other common pathogenic microorganisms.In summary,this study developed and optimized the use of CdSe/ZnS quantum dots and CdSe/ZnS quantum dot microspheres for single and multiple target flow-through immunochromatographic assays.As a result,rapid and quantitative detection of Yersinia pestis,Escherichia coli O157:H7,and Salmonella enterica serovar Typhi was achieved.