Magnetically controlled fluorescence biosensor for simultaneous detection of aflatoxin B1 and its toxin-producing gene aflD

The aflatoxin B1 (AFB1) was considered as the most toxic natural compound and exists widely in the world, it is great significance to develop a high-performance sensor for simultaneously detection AFB1 and its toxin- producing gene aflD. In this paper, a magnetically controlled fluorescent sensor was developed, ssDNA1/ ssDNA2 was modified on graphene quantum dots (GQDs)/Mn:ZnS quantum dots (QDs) as an energy donor, and cDNA/Apt modified by black hole quencher (BHQ) was coupled with MNPs as an energy acceptor, which leaded to fluorescence quenching through donor-acceptor energy transfer. Parts of fluorescent probes were separated from magnetic carriers when the sensor was incubated with the targets. After magnetic separation, the fluorescence intensity of the fluorescent probe released from the supernatant was positively correlated with the target concentration. The simultaneous detection of aflD and AFB1 was realized. The sensor displayed a wide detection range (0.1-500 nM and 0.1-500 ng/mL) for aflD and AFB1, with detection limits of 0.021 nM and 0.038 ng/mL for aflD and AFB1. The magnetic fluorescence biosensor showed a good recovery rate in real rice flour and corn flour samples. The magnetic control fluorescence biosensor had the high sensitivity and specificity. This strategy provided a simple, efficient and sensitive method for food safety monitoring.