Enzyme-free amplified and ultrafast detection of aflatoxin B1 using dual-terminal proximity aptamer probes

Aptamer probes provide an opportunity for achieving rapid and on-site detection of food contaminants. Herein, we proposed a general design strategy for aptamer probes enabling enzyme-free amplified, ultrafast and one-test tube homogeneous detection of aflatoxin B-1 (AFB(1)). The key feature of the aptamer probe is designed with dual-terminal proximity structures, allowing the binding of one molecule to light up two fluorophores, leading to enzyme-free amplification and a remarkable improvement of signal to background ratio and sensitivity for AFB1 detection. This aptamer probe could accommodate quick response to AFB1, and the detection process could be finished within 1 min, ranking one of the quickest assays for AFB1. AFB1 detection of broad bean paste and peanut oil conferred satisfactory recoveries ranging from 90.3% to 114.8%. Contributed to the generality and simplicity of the design strategy, this structure-switching probe could potentially act as a general platform of on-site detection for food safety.