An aptasensor-based fluorescent signal amplification strategy for highly sensitive detection of mycotoxins

Aflatoxin B1 (AFB1) is one of the most toxic mycotoxins that pose great health threats to humans. Herein, an aptasensor-based fluorescent signal amplification strategy is developed for the detection of AFB1. Initially, the AFB1 aptamers labelled with carboxyfluorescein (FAM) are adsorbed onto graphene oxide (GO), triggering energy transfer. When AFB1 is present, the aptamer molecules specifically capture the AFB1, disrupting the energy transfer between the aptamer molecules and GO. Subsequently, deoxyribonuclease I (DNase I) is introduced into the reaction system to promote the hydrolysis of the aptamers, causing the release of FAM and AFB1. The released AFB1 further binds to the aptamers adsorbed onto GO, triggering fluorescent signal amplification. In this manner, large amounts of FAM fluorescence signals are restored, enabling the quantitative detection of AFB1. Key parameters influencing the sensing performance and the energy transfer mechanism are systematically investigated. To further demonstrate the versatility of the aptasensor, we also perform the detection of ochratoxin A (OTA) and fumonisin B1 (FB1). This study can be extended to monitor other contaminants in food by modifying the corresponding aptamers and provides a novel approach for simultaneous detection and the development of aptasensors.