An ?off-on? electrochemical luminescence biosensor with aggregation-induced emission for ultrasensitive detection of aflatoxin B1

This work describes a novel off-on biosensor for super-sensitive and selective detection of aflatoxin B1 (AFB1). In the biosensor, electrochemiluminescence (ECL) and aggregation-induced emission (AIE) work together to enhance ECL performance by a dibenzo-[b,d]thiophene sulfone-based conjugated microporous polymer, and hairpin DNA1 (H1) and ferrocene (Fc)-apt act as the switches for the off-on mode. In the absence of target AFB1, the ECL signal is inhibited because of the steric-hindrance effect, and the biosensor remains in the off state. In the presence of AFB1, ECL signal recovery is observed caused by the specific recognition between the AFB1 and Fc-apt, i.e., the biosensor changes to the on state. Under optimal experimental conditions, AFB1 can be quantified from 1 pg center dot mL-1 to 1 mu g center dot mL-1 with an ultralow detection limit of 0.46 pg center dot mL-1 by the off-on biosensor. The biosensor exhibited good practicability for AFB1 assay in corn samples, thus providing a simple and sensitive method for monitoring food safety.

Automated summary

This work presents a novel off-on biosensor for highly sensitive and selective detection of aflatoxin B1 (AFB1). The biosensor utilizes electrochemiluminescence (ECL) and aggregation-induced emission (AIE) to enhance ECL performance, and employs hairpin DNA1 (H1) and ferrocene (Fc)-apt as switches for the off-on mode. In the absence of AFB1, the biosensor remains in the off state, but in the presence of AFB1, it switches to the on state, allowing for quantification of AFB1 with an ultralow detection limit of 0.46 pg center dot mL-1.