Production method of silver-clad gold nano-rods and their application

Abstract

The invention discloses a production method of silver-clad gold nano-rods and their application and belongs to the technical field of food quality detection and analysis. Au@ag nano-rods are produced, and with the surface enhanced fluorescence of the nano-rods, the nano-rods are successfully applied to the detection of the gene O157:H7easeA of E. coli. Compared with the traditional methods, the method has the advantages that detection limit is greatly lowered, sensitivity is improved, and good stability is achieved. According to the principle of fluorescence enhancement-weakening, a standard curve for gene O157:H7ease detection of E. coli is built, a linear range is from 10<-17> M to 10<-11> M, correlation coefficient R2 is 0.9947, and the detection limit is 3.33*10<-18> M (S / N = 3). The method has the advantages that specificity is good, labelling experiments show that eaeA gene recovery rate is 98.36% to 101.67%, with good stability, and the nano-rods are applicable to the detection of the gene O157:H7ease of E. coli and have a promising application prospect.

Description

technical field [0001] The invention relates to a preparation method and application of silver-coated gold nanorods, belonging to the technical field of food quality detection and analysis. Background technique [0002] Escherichia coli (E.coli) is a representative bacterium of the genus Escherichia (Escherichia). It is the most important and most abundant bacterium in the intestinal tract of humans and many animals, and it mainly parasitizes in the large intestine. When it invades some parts of the human body, it can cause infections such as peritonitis, cholecystitis, cystitis and diarrhea. Symptoms of people infected with E. coli are stomach pain, vomiting, diarrhea and fever. Infection can be fatal, especially in children and the elderly. [0003] The pathogenic substances of Escherichia coli are mainly: (1) invasiveness: including K antigen and settlement factor; (2) endotoxin: the cell wall of Escherichia coli containing endotoxin has endotoxin activity, and the lipi...

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Problems solved by technology

[0005] However, traditional methods for detecting bacteria are done by morphological characterization or biochemical analysis, which cannot provide accurate conclusions on bacterial species so that identification at the strain level and detection of bacteria isolated from the environment cannot be achieved; while testing It is very time-consuming to carry out and data processing, and cannot meet the fast and accurate real-time monitoring required for bacterial detection

The PCR method is greatly affected by the sample, especially in the inspection of food-borne harmful microorganisms, the ingredients in the food (sugars, acids, oils, etc.) will interfere with the normal progress of the reaction, and the detection environment and intermediate processing links will also Bring some PCR reaction inhibitors, so that PCR presents a high false positive and false negative rate

Although ELISA has high sensitivity and repeatability, it also has defects such as large sample size of pathogenic bacteria, cumbersome operation, expensive kit, high cost, poor accuracy and complicated operation, which requires professional training.

Although the biosensor method has good stability and high precision, it generally has the disadvantage of expensive instruments, which cannot meet the detection requirements of pathogenic bacteria in large-scale samples, and the progress of commercialization is very slow.

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