摘要
An electrochemical immunosensor was developed for sensitive assay ofE. coli in urban sludge, in which electron mediator-mediated enzymatic catalysis and gold nanoparticles（AuNPs） were utilized for signal amplification. The immnuosensing platform chitosan-thionine（chit-thio）/poly（amidoamine） dendrimer-encapsulated AuNPs [PAMAM（Au）] composites were first prepared from chit-thio and PAMAM（Au） using the layer-by-layer method to provide a matrix for high-stability and high-bioactivity bindings of the capture antibody（cAb）. Moreover, the {dAb-AuNPs-HRP} nanoprobes were designed to exploit the amplification effect of the carrier AuNPs due to the loading amounts of horseradish peroxidase（HRP）and the detection antibody（dAb）. The sandwich-type immunoassay was then successfully used to assay E. coli based on the oxidation of thionine as a result of H2O2-induced enzymatic catalytic reaction by HRP. This study presents a powerful tool in electrochemical immunoassay for E. coli detection with rapid response, high-sensitivity and high-specificity, providing a potential new tool for feasibility assessment of sludge recycle.
An electrochemical immunosensor was developed for sensitive assay ofE. coli in urban sludge, in which electron mediator-mediated enzymatic catalysis and gold nanoparticles（AuNPs） were utilized for signal amplification. The immnuosensing platform chitosan-thionine（chit-thio）/poly（amidoamine） dendrimer-encapsulated AuNPs [PAMAM（Au）] composites were first prepared from chit-thio and PAMAM（Au） using the layer-by-layer method to provide a matrix for high-stability and high-bioactivity bindings of the capture antibody（cAb）. Moreover, the {dAb-AuNPs-HRP} nanoprobes were designed to exploit the amplification effect of the carrier AuNPs due to the loading amounts of horseradish peroxidase（HRP）and the detection antibody（dAb）. The sandwich-type immunoassay was then successfully used to assay E. coli based on the oxidation of thionine as a result of H2O2-induced enzymatic catalytic reaction by HRP. This study presents a powerful tool in electrochemical immunoassay for E. coli detection with rapid response, high-sensitivity and high-specificity, providing a potential new tool for feasibility assessment of sludge recycle.
基金
Supported by the National Natural Science Foundation of China（Nos.21205051, 51608235） and the Key Project of the Ministry of Education of China（No.210078）.
