A silicon-based functional self-assembled aptasensor for the detection of aflatoxin B1 by SERS sensing

One of the most harmful contaminants found in corn and its products is aflatoxin B1 (AFB1) and thus developing reliable detection methods is of great significance to consumers and the food industry. In this research, Au^MBA@Ag nanoparticles (NPs) and AgNPs deposited on a silicon wafer (Si@AgNPs) were functionalized with an aptamer and its complementary strand, respectively, and self-assembled into a SERS aptasensor, which generated strong SERS signals. AFB1 bound to the aptamer prior to the complementary chain, causing Au^MBA@Ag NPs to detach from Si@AgNPs. The complex dissociated, leading to a decrease in signal intensity from the solid-phase substrate. Under optimal conditions, the linear detection range was 0.05-20.0 ng mL^-1, and the detection limit was 0.039 ng mL^-1. Notably, the aptasensor demonstrated a recovery rate between 92.77% and 110.13% when utilized for the detection of AFB1 in corn flour and oil, indicating its good potential for detecting AFB1 in real sample matrices. In conclusion, a quantitative and reliable specific SERS detection system for AFB1 was developed in this study with significant applicability to food safety.