Development Of A Colloidal Gold-Based Immunochromatographic Strips For The Detection Of Staphylococcus Aureus

In this paper,the colloidal gold immunochromatographic rapid test strip(GICA)were developed for the determination of Staphylococcus aureus(S.aureus).The detection limit was reduced by two patterns of signal amplification lateral flow immunoassay.This method has been proven useful for rapid detection of Staphylococcus aureus in food.Surface protein SdrD was prepared by inducing.The expressed protein was purified with immunoaffinity chromatography and used to immunize New Zealand white rabbits to prepare polyclonal antibodies.The other antibody mouse anti-Staphylococcus aureus monoclonal antibody.Sandwich for S.aureus was developed using anti-SdrD antibody as the capture antibody and amouse anti-Staphylococcus aureus monoclonal antibody as the detection antibody.Developing Staphylococcus aureus colloidal gold immunechromatography test strip detection method,the partical size of colloidal gold is 20 nm to labeled antibody;the best pH value of colloidal gold label antibody is 8.5,the amount of antibody is 24 pg/mL;capture antibody concentration is 0.6 mg/mL;second antibody and the nano-colloidal gold-antibody probe was diluted to 100 and 5 fold;choose Millipore HF90s models of nitrocellulose membrane as solid phase carrier;2.5%BSA diluted with PBS as block processing fluid and blocking 1 h to the NC membrane.This method can be measured for ovotransferrin standard of detection limit is 1.57×106CFU/mL.And Salmonella,Escherichia 0157:H7,Enterobacter sakazakii,Shigella does not produce cross-reactive with it.When enrichment time is 8h,the detection limit of Staphylococcus aureus of pork,chicken and milk can reach 2.34×10 CFU/g(mL).Two patterns of signal amplification lateral flow immunoassay(LFIA),which used anti-mouse secondary antibody-linked gold nanoparticle(AuNP)for dual AuNP-LFIA were developed.The second Gold Nanoparticle Probes is 30 nm.This method can be measured for ovotransferrin standard of detection limit is 1.57×105 CFU/mL.When enrichment time is 6h,the detection limit of Staphylococcus aureus of pork,chicken and milk can reach 2.34×10 CFU/g(mL).And the detection step is simple,visual results can be obtained,without the aid of instruments,the entire detection time of less than 10 min,suitable for rapid screening of large numbers of samples.