Ultrasensitive Fluorescent Immunoassay for Aflatoxin B1 Detection Using SiO2 Nanospheres

Early detection and control of aflatoxin B1 (AFB1) contamination are essential for ensuring food safety. However, conventional analytical methods frequently encounter technical limitations including operational complexity and insufficient sensitivity. To overcome these limitations, an ultrasensitive fluorescent immunoassay detection of AFB1 was developed based on SiO 2 nanospheres. These highly dispersible nanospheres were utilized as carriers to co-load CdSe/ZnS quantum dots (QDs) and AFB1-specific aptamers (Apt), resulting in the construction of SiO₂@QDs@Apt fluorescent probes with enhanced signal amplification (7.51 \(\times\) 10 3 -fold improvement in sensitivity compared to the QDs@Apt method without SiO₂ nanospheres). The assay achieved an ultra-low detection limit of 5.06 \(\times\) 10 –7  ng/mL and a broad linear range of 10 −7 ~10 ng/mL. Validation through standard spiking experiments and real sample analysis confirmed the method’s accuracy and reliability. This strategy demonstrated higher sensitivity than the commercial ELISA kit tested, suggesting its potential utility for trace AFB1 monitoring in certain food matrices. Overall, this simple, specific, and cost-effective strategy could serve as a sensitive analytical platform for AFB1 monitoring in food safety laboratories.