Study On The Detection Of CystatinC And Clenbuterol Hydrochloride Based On Fluorescence Quenching Immunoassay

Objective: As an ideal marker that is not easily interfered by external factors,cystatin C(Cys C)is mainly used to evaluate glomerular filtration rate(GFR),which reflects renal function.In recent years,Cys C has also played an important role in the evaluation of cardiovascular,carotid atherosclerosis or other diseases such as liver disease,and has become a clinical test index with broad application prospects.However,there are limitations in its detection methods,and it is necessary to carry out in-depth research on Cys C detection methods.Clenbuterol hydrochloride(CL)can increase the carcass lean rate of animals,so it is often used as a kind of "clenbuterol" for illegal addition,and causes frequent food poisoning cases.Therefore,the CL research of detection method is imperative.This study aims to establish a convenient,rapid,sensitive and suitable Cys C and CL quantitative detection method for grassroots census,in order to provide a new perspective and technical reference for clinical and food safety detection and monitoring.Methods:(1)Background fluorescence quenching immune chromatographic assay(b FQICA)is a kind of quantitative method developed on the basis of the traditional gold immune chromatographic assay(GICA).The immunoassay technique added a layer of “ background fluorescence ” on the solid phase of the GICA immunochromatographic test strip,using gold nanoparticles as a quencher,and using the double antibody sandwich principle in the immune reaction.Quantitative detection of Cys C was performed at the relative fluorescence intensity(F1/F2)between the detection line(T line)and the "background fluorescence".(2)Fluorescence internal filtration immunoassay(FIFI)is a liquid-liquid homogeneous reaction based on the fluorescence internal filtration effect,using gold nanoparticles as a quencher,using the principle of competition in the immune reaction.Quantitative detection of CL was performed at the fluorescence intensity.Results:(1)In the range of 0.0-100.0 ng/m L,the concentration of Cys C showed a good correlation with the relative fluorescence intensity(F1/F2)(r=0.9977),the detection limit was 0.69 ng/m L,and the recovery rate reached 87.9%?110.8%.The differences of both intra and inter-batch were less than 15% in three batches.The common interfering substances in serum and anticoagulants have no effect on the test results,and there is no significant difference compared with the clinical test method(t=0.963,P=0.338 > 0.05).(2)In the range of 0.0-5.0 ng/m L,the concentration of clenbuterol and fluorescence intensity showed a good correlation(r=0.9986),thedetection limit was 0.01 ng/m L,and the recovery rate reached 98.1% ? 101.2%.The differences of both intra and inter-batch were less than 15% in three batches.Compared with the enzyme-linked immunosorbent assay(ELISA),there was no significant difference(t=1.401,P=0.169> 0.05).Conclusion:(1)Background fluorescence quenching immune chromatographic assay can quickly and sensitively detect serum cystatin C,and it is simple and easy to perform,and has strong anti-interference ability.It can be applied to the survey of community and primary medical institutions.(2)Fluorescence internal filtration immunoassay technology can quickly and sensitively detect clenbuterol hydrochloride.The instrument is portable and low in cost,and it is expected to provide important technical support in food safety testing and monitoring.