A dual signal-on biosensor based on dual-gated locked mesoporous silica nanoparticles for the detection of Aflatoxin B1

Aflatoxin B1 (AFB1) is a highly toxic mycotoxin that can contaminate foods. Hence, a surface-enhanced Raman scattering (SERS) and fluorescence dual signal-on biosensor was developed for AFB1 detection. Specifically, aminated mesoporous silica nanoparticles (MSNs) were used as nanocontainers to load the Rhodamine 6G (R6G) with fluorescence and Raman effects, aptamers and polydopamine (PDA) were sequentially assembled on the surface of the MSNs as dual-gated molecules, and MXenes and Au nanorods were used as SERS substrates. After adding AFB1 under acidic conditions, the degradation of PDA and specific bringing of the aptamer with AFB1 resulted in the release of R6G. Results showed that AFB1 could be quantified by Raman and fluorescence spectroscopic with detection limits of 0.133 pg mL−1 and 0.214 pg mL−1, respectively. Moreover, the biosensor could be applied to the detection of AFB1 in real peanut, maize and badam samples, providing a possible alternative solution for the detection of other analytes.