A signal-off aptamer sensor based on competition with complementary DNA and click polymerization for electrochemical detection of AFB1

A new, simple and low-cost electrochemical analysis approach employing click polymerization as the signal amplification strategy was developed for the highly sensitive assay of aflatoxin B-1 (AFB(1)). First, the aptamer served as the capture probe for AFB(1) self-assembled on the surface of the Au electrode via Au-S bonding. After complementary DNA (c-DNA) modified with azide groups was hybridized with the aptamer, a massive click polymer was introduced as a signal tag via click chemistry. Finally, the captured AFB(1) competed with the c-DNA to bind the aptamer and the c-DNA was shed from the electrode surface and the current intensity was reduced. The electrochemical aptamer sensor is easy to operate, selective and sensitive, and also exhibits excellent reliability in detecting AFB(1) in actual samples. A rapid, simple, efficient and sensitive platform for AFB(1) analysis is proposed in this work, and the strategy can be further extended to trace analysis of other analytes, safety detection, environmental monitoring and disease diagnosis after replacing the corresponding capture probes, with promising applications in the fields of food hygiene and safety.