Click Chemistry And EATRP Reaction Based Electrochemical Biosensor For Antibiotic And Pathogenic Bacteria Detection Application

This study focused on the construction of an electrochemical biosensor for kanamycin based on copper-catalysed azide-alkyne cycloaddition(Cu AAC)click chemistry and electrochemically mediated atom transfer radical polymerization(eATRP)reaction,by using the specific recognition function of aptamer modified on gold electrode.On the basis of this sensor,the employment of bacteria to reduce copper(Ⅰ)from copper(Ⅱ)provided the catalyst for the click chemistry reaction,realizing the further application of the reaction system.Due to the different copper reduction ability of various numbers of bacteria,the different progress of click chemistry reaction and the amount of electroactive polymer produced by the eATRP reaction was fulfilled,thus by collecting and analysing electrical signals,sensitive detection of pathogenic bacteria can be realized.The results obtained in the study were as follow.1.Employing gold electrode as the sensor substrate,electrochemical biosensor based on click chemistry and eATRP reaction was constructed and kanamycin was selected as the model molecule for detection.In the experiment,the reduction potential of copper(I)was first determined,and then the modification process and feasibility of the sensor were characterized.After optimizing the reaction conditions of the biosensor,the linear detection range and the limit of detection(LOD)were explored.The electrochemical biosensor realized the linear detection of kanamycin from 0.1 pg/m L to 100 ng/m L and the LOD was as low as 7.89 fg/m L.It possessed good sensitivity,specificity and anti-interference ability in milk samples which hold certain application potential in drug quantitative analysis,food safety and biological research.2.An electrochemical biosensor for pathogenic bacteria based on click chemistry and eATRP was constructed.Staphylococcus aureus(S.aureus)and Escherichia coli(E.coli)were employed as the model pathogens in the experiment.The modification process of the biosensor was first characterized and the feasibility of the electrochemical biosensor was verified.Under the optimal reaction conditions,the electrochemical biosensor realized the linear concentration from 102 to 107 CFU/m L for both S.aureus and E.coli,and the LODs were 4 CFU/m L and 6 CFU/m L,respectively,which also realized the residual detection of S.aureus and E.coli in milk samples.In addition,we also applied the electrochemical biosensor to the screening of bacteria-sensitive antibiotics.Compared with the traditional flat-coated drug susceptibility test,the electrochemical biosensor-based drug screening method can obviously improve the testing efficiency,which showed important application prospects in the research of biomedicine and clinical treatment.In this study,a kanamycin electrochemical biosensor was constructed based on the Cu AAC and eATRP reactions.On this basis,the bacterial copper reduction system was further innovatively employed to the traditional click chemistry reaction into sensitive detection of S.aureus and E.coli,as same as the screening of bacterial sensitive antibiotics.The electrochemical biosensor can not only increase the detection of different types of antibiotics by replacing different nucleic acid aptamer,but also be used to detect other bacteria besides S.aureus and E.coli due to the widespread copper-reducing system existed in various bacteria.Meanwhile,it can save time for screening bacterial susceptibility antibiotic,showing promising applications in food safety,biomedical research and clinical treatment.