The Rapid Detection Method Of Staphylococcus Aureus With Quantum Dots Nanospheres

In recent years,the poisoning caused by staphylococcus aureus occurred many times.Staphylococcus aureus detection based on microbial cultures is relatively accurate,but it is time-consuming,therefore,a sensitive,rapid and reliable method to detect staphylococcus aureus can be badly in need.In modern rapid detection methods,chemical instrument detection can reflect the result fastly,intuitively and sensitively.However,how to transfer microbial signals into detectable chemical signals will be quite important in the process of testing.This paper aims to tag IsdA rabbit anti-antibodies with quantum dots microspheres,adopt the way of syringe and membrane filter combination for detecting of staphylococcus aureus.Using mercaptoacetic acid as stabilizer,compare one-step method and two-step method to synthesize CdTe quantum dots.One-step method is better than two step method.Finally,using GSH as the stabilizer,one-step method to synthesize the fluorescence intensity better CdTe quantum dots,and the infrared characterization,ir absorption spectra showed that function of GSH-CdTe quantum dots containing carboxyl and amino groups,which can be applied into the next phase of biology.Restructuring of IsdA protein expression,purification,immunizing rabbits and mice,preparation of polyclonal antibody,however,antiserum and antibody titer were poor.0.1 mM IPTG inducing expression of logarithmic phase of e.coli BL21(DE3)-pET26b-IsdA,IsdA successfully expressed by recombinant proteins,and the expression of soluble;Purification of IsdA recombinant protein;Immunizing rabbits and mice,preparation of polyclonal antibodies;Glutathione immune quantum dots all uv wavelength scanning figure show that quantum dots are connected to the antibody,the fluorescence intensity of QDS is enhanced,which suggests that quantum dots connected with antibodies successfully.Markers of quantum dots have been established microspheres IsdA method to detect staphylococcus aureus rabbit antibody immune resistance,the method has obvious specificity adsorption on staphylococcus aureus,at the same time,the slight non-specific adsorption of E.coli is showed since the detection limit of 2.37×105 CFU/mL.We mainly tested the raw pork samples,with a 102-103 CFU/mL of standard bacteria liquid samples,in milk,it can’t be checked completely in 1 h,until 2 h,it can be checked.