Study On Quartz Crystal Microbalance Immunosensor Assay For The Detection Of Staphylococcus Aureus

Staphylococcus aureus can infect food with high probability which widely existing in nature.Food poisoning caused by Staphylococcus aureus is the second most,the enterotoxin made by Staphylococcus aureus is also threatening human's health.Besides,so far the detection of Staphylococcus aureus is Plate Count method,which is complicated,time consuming,heavy workload and so on.So it is necessary to found a method,which has many features,such as use easily,high sensitivity,efficiency,accuracy,strong specificity.In this paper,the quartz crystal microbalance immunosensor was founded for the determination of.Staphylococcus aureus in the food.Then Staphylococcus aureus was detected according to the frequency shifts,which caused by the antigen-antibody binding reaction on the surface of piezoelectric sensor chip.Au nanoparticles with antibody was used to amplify the response.Results indicate that the 0.30 ?g/?L mouse monoclonal antibody with acetic-acetate buffer pH 5.0 was used to be optimum coupling condition for coating the chip;for the colloidal gold labeled antibody,the optimum partical size of colloidal gold is 30 nm,the optimum pH value of colloidal gold label antibody is 8.5,the amount of antibody is 42 ?g;PBST was used as the background solution;different concentrations of Staphylococcus aureus were detected with the 60?L/min as the speed of injection and had a good liner range(2.1×102-2.1×105 CFU/mL),a limit of detection(LOD)was as low as 22 CFU/mL.For a single sample,it just cost 20 min to detection Staphylococcus aureus.In the specificity tests,it showed a highly specific to Staphylococcus aureus,which almost not capture Salmonella,E.coli O157:H7,Enterobacter sakazakii and Shigella.The assay was validated for the determination of Staphylococcus aureus in the milk,pork,chicken and dumplings with a great relative(correlation coefficient,0.9234)to the result of Plate Count method.In this study,the QCM immunosensor showed rapid,easy to operate,sensitive,low limit detection.It will be applied to detect Staphylococcus aureus in the mass food samples.