Study On Biomimetic Enzyme-Linked Immunosorbent Assay Method Based On Nanozyme Labeling For The Detection Of Sulfadiazine

Sulfonamides are a kind of common broad-spectrum antibiotics with good antibacterial effect and low price,are widely used in livestock and poultry breeding.In recent years,misuse can lead to residues in human body,animals and the environment,which have posed a serious thread to human health.In order to prevent drug residues from causing harm to human beings,a rapid and sensitive analytical approach for the determination of sulfonamide is urgently needed.Immunoassay is widely used in the detection of veterinary drugs residues due to its high specificity,no expensive instruments and high cost effectiveness.Biomimetic enzyme-linked immunosorbent assay is the most common method in the application of immunoassay.The method was based on bionic antibodies ad combined the catalytic amplification effect of the natural enzymes as markers.However,natural enzyme were sensitive to environment changes,which restrict its development.In recent year,nanomaterial mimetic enzyme have been widely used in immunoassay as markers due to their similar catalytic activity to natural enzymes.In this study,the molecularly imprinted polymers were used as bionic antibodies for recognition,and the nanozyme labeled as a marker take the place of horseradish peroxidase,providing two methods for detecting sulfadiazine residues.The main findings are as follows:1.Study on biomimetic nanozyme-linked immunosorbent assay method based on Au@SiO₂ nanozyme labeling for the detection of sulfadiazineThe molecularly imprinted polymer films were selected as bionic antibody,which was prepared directly on the surface of a 96-well plate using sulfadiazine as template molecule.And the Au@SiO₂ nanoparticles labeling as a marker.a rapid and novel biomimetic nanozyme-linked immunosorbent assay has been established.Under the optimal condition,the limit of detection(LOD,IC₁₅)of this assay was 0.2 mg L^-1.Beef sample was choosed to conduct the recovery experiments by this method,and the recoveries were 78.00%to90.96%.The assay could be used to detect sulfadiazine residues in pork and chicken samples,and the results were not significantly different from those obtained by high performance liquid chromatography.2.Detemination of sulfadiazine residue in food based on Au@Pt@SiO₂nanozyme-labeled Biomimetic ImmunoassayA new biomimetic immunoassay was developed using the biomimetic antibodies to detect sulfadiazine using Au@Pt@SiO₂ bimetallicnanozyme as a marker.The synthesis conditions of the polymer were optimized and the catalytic activity of the enzyme was increased This method was based on a competitive reaction between a nanozyme-labeled sulfadiazine antigen and a biomimetic antibody.Under the optimal conditions,the limit of detection(IC₁₅)and sensitivity(IC₅₀)of this method is 0.09 mg L^-11 and 6.1 mg L^-1,respectively.In order to evaluate the accuracy of the method,honey and milk（a）samples spiked with sulfadiazine was analysed,and the recovery was in the range of 70.8-90.2%.The method was also used for quantitative analysis of sulfadiazine residues in milk powder and milk samples,and the results had a good correlation with the results determined by high performance liquid chromatography.