Method for simultaneously detecting two types of pathogenic bacteria based on two-color time-resolved fluorescence labeling-magnetic separation aptamer recognition

Abstract

The invention relates to a method for simultaneously detecting two types of pathogenic bacteria based on two-color time-resolved fluorescence labeling-magnetic separation aptamer recognition; the method is used for detecting salmonella typhimurium and staphylococcus aureus in milk and dairy products. The method comprises the steps of enabling an aptamer of the salmonella typhimurium and an aptamer of the staphylococcus aureus to be respectively coupled with NaYF4: Ce / Tb time fluorescence resolution nanomaterial and NaGdF4: Eu time fluorescence resolution nanomaterial to form signal probes; meanwhile, enabling the two aptamers to be coupled with Fe3O4 magnetic nanomaterial to form capture probes; when a target material exists, finally forming a sandwich compound due to the specific recognition of the aptamer for the target material. The salmonella typhimurium and the staphylococcus aureus can be quantitatively detected by monitoring the intensities of fluorescence signals at the parts of 544nm and 615nm, the linear ranges of the salmonella typhimurium and the staphylococcus aureus are respectively 10<2>-10<5>cfu ml<-1> and 10<2>-10<5>cfu ml<-1>, and the lowest detection limits of the salmonella typhimurium and the staphylococcus aureus are respectively 15cfu ml<-1> and 20cfu ml <-1>. The method can be used for detecting the two types of pathogenic bacteria at the same time, and has the advantages of being high in sensitivity, rapid, simple and convenient. The method is applied to the detection of the milk and the dairy products, and is accurate and reliable in results.

Description

technical field [0001] A method for simultaneous detection of two pathogenic bacteria based on two-color time-resolved fluorescent labeling-magnetic separation aptamer recognition, involving the field of nanomaterials and analytical chemistry technology, used for simultaneous detection of Salmonella typhimurium and Staphylococcus aureus in food . Background technique [0002] Foodborne diseases usually refer to diseases that lead to human infection or poisoning due to the ingestion of biological, physical, and chemical toxic and harmful substances into the human body. Foodborne pathogens are pathogenic bacteria that can cause food poisoning or infection. Salmonella typhimurium and Staphylococcus aureus are the most common pathogens causing foodborne illness. Salmonella typhimurium is an aerobic or facultative anaerobic Gram-negative bacterium with flagella all over the body and no capsule. The optimum growth temperature is 34°C to 37°C and the optimum pH is 7.0 to 7.8. Sa...

AI Technical Summary

Problems solved by technology

Among them, ELISA has been highly commercialized and has become a commonly used detection method in food safety, environmental monitoring, and medical diagnosis. It combines the high efficiency of enzyme catalysis and the specificity of antigen-antibody reactions to achieve the purpose of rapid and sensitive detection. The method still requires a sufficient number of bacteria to react to the detection of pathogenic bacteria, so the pre-enrichment culture stage is required before the detection. This process is laborious and time-consuming, which limits its further application.

Both ELISA and GICA are based on antigen-antibody affinity reaction. As a recognition molecule, an antibody is easily affected by external conditions, especially temperature, and the preparation of antibodies needs to go through animal or cell experiments, which is tedious, time-consuming and costly, so the detection cost is also high. high

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