Study Of Aptasensor Based On Nanomaterials In Rapid Detection Of Foodborne Pathogenic Bacteria

Food-borne pathogenic bacteria are the type of harmful microorganisms that spread with food as the carrier.They have a wide range of transmission pathways and can occur in any stage of food processing,packaging,and storage.They are prone to cross-contamination under certain conditions.They are the major potential cause of food-borne diseases.After infected with food-borne pathogenic bacteria,they may cause mild food poisoning,acute gastroenteritis,and even life-threatening.Food safety incidents caused by foodborne pathogens emerge in endlessly every year in China.Food safety is related to public health and social and economic development.To strengthen the accurate prevention and control of food-borne pathogens and improve the efficiency of on-site detection are the important tasks of current food safety work.At present,the traditional detection methods mainly include traditional microbial culture method,molecular biology technology,and immunological detection method.These detection methods have the disadvantages of high requirements for sample pretreatment,long detection time,and complex operation.Therefore,it is an urgent problem to develop a fast,sensitive,and efficient new method for the detection of food-borne pathogenic bacteria.Biosensor is a food-borne pathogenic bacteria detection technology with great application potential.The aptamer-based biosensor takes the nucleic acid aptamer with high affinity as the recognition element,and detection signals can be amplified by combining with a nanomaterial.And in practical application,the aptasensor can quickly capture the target,convert the recognized target signal into the readable value,has multiple times of quantitative detection sensitivity,and has become a research hotspot in the field of foodborne pathogenic bacteria detection.In this study,a novel biosensor for the detection of food-borne pathogens based on aptamers and nanomaterials was constructed,which can achieve multi-target synchronous detection and developed a new fast,sensitive and efficient detection method for food-borne pathogens.The main research contents are as follows:(1)Based on the inherent color-changing effect of the pH indicator and the high affinity of the aptamer to a target molecule,the pH color-changing nanoparticles were prepared by the self-assembly method,bovine serum albumin(BSA)serving as stabilizer and aptamer serving as recognition unit were simultaneously attached on the surface of the pH color-changing nanoparticles as the colorimetric response signal label for detecting food-borne pathogenic bacteria.Based on the signal amplification effect of nanoparticles,a novel food-borne pathogenic bacteria synchronous colorimetric biosensor was constructed using 96-well plates to synchronously and rapidly detect microorganisms,and the double-target detection of Escherichia coli(E.coli)and Salmonella typhimurium(S.typhimurium)was realized.The actual sample was detected,and it was confirmed that the method had good sensitivity,stability and specificity.(2)Based on the flowability and color aggregation effect of the colloidal gold nanomaterials,ampicillin which specifically identifies gram-positive bacteria and gram-negative bacteria was used as the recognition probe,and a novel lateral flow chromatography biosensor which can simultaneously detect grampositive bacteria and gram-negative bacteria was developed by using the colloidal gold immunochromatography technology,wherein the aptamer serves as second recognition probe to form the sandwich detection mode.Quantitative analysis was performed using the colloidal gold detector,and the feasibility of the sensor in honey samples was verified.