Study On Rapid Detection Device And Traceability System For Antibiotic Residues In Milk Based On Aptasensor

Food safety issues are related to the development of the country,but also to the survival and health of everyone.Tetracycline is a common antibiotic,which is widely used in animal husbandry in addition to medical treatment.However,excessive use of tetracycline cause excessive tetracycline in meat and milk to cause serious damage to human kidneys,liver,ears and teeth and so on.The current mainstream detection methods have long cycle times,complex operations,and high requirements for experimenters.The storage of test results and data has a risk of being unreliable and tampered with,and faulty products cannot be effectively traced.Electrochemiluminescence aptasensor use nucleic acid aptamers as recognition elements to rapidly and accurately detect tetracycline residues in milk.It is a promising rapid detection method,but there is currently a lack of electrochemical-based rapid detection device for luminescent aptasensor.Therefore,a portable electrochemiluminescence rapid detection device was developed in this paper.The screen-printed electrode was used as the substrate,and the nucleic acid aptamer was used as the recognition element to detect tetracycline in milk.The key nodes of the chain and detection data were protected and shared.The research contents are as follows:（1）A portable electrochemiluminescence based rapid detection system,AQS-ECL,based on SIPM was developed.The composition of the potentiostat circuit was studied,and the potentiostat circuit with the peripheral circuit was designed,STM32 was used as the lower site machine master control chip to realize the electrochemical excitation and the acquisition of electrochemical signals at different potentials.In the bottom solution test of Fe（CN）₆^3-/Fe（CN）₆^4-,RSD_Oof the oxidation peak was 1.4%,and RSD_Rof the reduction peak was 0.34%at steady state.The electrochemical signal was still accurately measured with an internal resistance（100 K）of the electrolysis cell after correction of the calibration curve.An electrochemical counter electrode could make the chemiluminescence of luminescent species on a working electrode within a certain scan potential range,with the help of this characteristic to collect weak light signals,use the SiPM single photon detector instead of the photomultiplier tube（PMT）,greatly reduce the volume under guaranteed detection efficiency,design the photon counting circuit for the calculation of photon number,develop the epistasis software using raspberry Pi as the epistasis machine.The detection data were visualized,and the electrochemiluminescence signal of luminol（10m M）hydrogen peroxide（0.4-0.003125 m M）system was detected using this electrochemiluminescence rapid detection system,showing a linear relationship with a fit of R²=0.991,the designed electrochemiluminescence rapid detection system satisfied the conditions for electrochemical and weak light detection.（2）Aiming at the rapid detection of tetracycline in milk,using AQS-ECL as detection tool,a new method based on Ag@AuNPs bimetallic nanoparticles enhanced ECL signal aptasensor for detection of tetracycline in milk was constructed.Large particles of AgNPs were obtained by in situ synthesis using sodium borohydride（Na BH₄）reduction and gradient centrifugation Ag@AuNPs bimetallic,AgNPs contributed to the electrochemiluminescence of luminol in hydrogen peroxide.The sulfhydryl groups through the 5’end of the aptamer could efficiently modified and Au-S was formed,which made the aptamer links robust and exhibited excellent linearity ranging from 0.01 ng/m L to 1000ng/m L for the detection of tetracycline,and the limit of detection（LOD）was 0.0033ng/m L.This sensor was convenient to carry and easy to operate compared with the designed rapid detection device.（3）The food safety information service platform was constructed,and the system was tested for access,and the sharing,protection,and management of test data would be achieved.This service platform had a RFID information entry client of turnover nodes,a detection information management platform,an information traceable platform-Wechat mini program.This food safety information service platform was built using web Django service and hyperledger fabric service,and the data was stored using My SQL+blockchain form,after testing the platform data of 200 nodes concurrent writing had a mean delay of1636.52 ms,and concurrent traceable data of 200 nodes had a mean delay of 4138.1 ms and concurrent traverse of the full data table of 100 nodes was supported with better performance.