Construction Of Molecularly Imprinted Electrochemical Sensor And Its Application In The Detection Of Vancomycin

Vancomycin,as a glycopeptide antibiotic,is often used to treat serious infections caused by gram-positive bacteria.It is currently the best type of antibiotic known to be effective.As the last line of defense against bacteria,vancomycin is used only when other antibiotics have no effect on the bacteria due to its strong medicinal properties.However,excessive use of vancomycin can lead to severe nephrotoxicity and ototoxicity,and due to the enrichment effect,some animal-derived foods will also contain vancomycin.If humans consume these foods for many years,it will cause vancomycin in the body.Accumulate and endanger human health.Although the traditional detection method of vancomycin shows good sensitivity and selectivity,the sample processing is complicated,the equipment is expensive,and the analysis time is long.The electrochemical sensor that uses molecularly imprinted polymer as the identification element has the characteristics of simple operation and fast response.In order to improve the selectivity and sensitivity of the molecularly imprinted electrochemical sensor,we also introduce specific binding with vancomycin on the basis of it.Polypeptide,used to detect vancomycin,the specific research content and results are as follows:A method based on molecularly imprinted electrochemical sensor to detect vancomycin was established.The glassy carbon electrode was polished and pretreated.After 400 s of electrodepositing gold nanoparticles in HAu Cl₄ by potentiostatic method,using vancomycin as template molecule,molecularly imprinted polymer was prepared by cyclic voltammetric electropolymerization in deoxygenated dopamine solution,Ethanol/acetic acid（v/v=95:5）is used as an eluent to remove vancomycin,and an imprinting cavity that specifically recognizes vancomycin is formed on the surface of the electrode.The surface of the glassy carbon electrode before and after gold plating was characterized by scanning electron microscopy.Under the conditions of 8 cycles of electropolymerization,elution for 20 minutes,and then recognition for 20 minutes,the molecular imprinting sensor has excellent performance in identifying vancomycin,which is 1×10^-11～1×10^-4mol/L vancomycin showed a good linear relationship within the concentration range.In order to improve the selectivity of electrochemical sensors,we based on the principle of combining vancomycin with the terminal peptide D-alanyl-D-alanine of the peptidoglycan precursor to inhibit bacterial cell wall synthesis,peptides that can specifically bind to vancomycin is designed.By introducing vancomycin-binding peptides when synthesizing molecularly imprinted polymers,a molecularly imprinted-polypeptide dual-recognition electrochemical sensor was prepared.The peptides labeled with fluorescein isothiocyanate proved that they can be well immobilized on the electrode surface.The results show that under the conditions of p H 7.0,elution time of 10 minutes,and recognition time of 20minutes,compared with molecularly imprinted sensors,dual recognition sensors have better selectivity and higher due to more vancomycin recognition sites.The sensitivity shows a good linear relationship in the concentration range of 1×10^-11～1×10^-4mol/L vancomycin,and the limit of quantification is as low as 10 p M.The double-identification electrochemical sensor prepared by us has a peak value after being stored in PBS for 4 weeks.The current signal value can still maintain 95.8%of the initial current value,with good stability.The double identification sensor successfully detected vancomycin in actual samples such as fetal bovine serum,probiotic beverages and honey,with a recovery rate of 92.16-104.67%.This study provides a highly sensitive and selective detection method for the analysis of vancomycin in complex matrices.