SSB-aptamer interaction-triggered SiO2NPs/HCR cascade signal amplification strategy for high-sensitivity aflatoxin B1 detection

Aflatoxin B1 (AFB1), a highly toxic and carcinogenic mycotoxin, is commonly found in food products and presents substantial risks to both human and animal health. To ensure food safety, high-performance analytical methods are essential for detecting AFB1. This study introduces a novel high-sensitivity detection approach for AFB1, based on the interaction between aptamers and single-stranded binding protein (SSB), with SiO 2 nanoparticles (SiO 2 NPs) serving as carriers for hybridization chain reaction (HCR)-mediated cascade signal amplification. In the presence of AFB1, the aptamer within the SiO 2 @DNA detection probe binds to AFB1, forming a complex that remains in the supernatant. The introduction of nicking endonuclease (Nb.BbvCI) cleaves the hybridized DNA sequence, thereby exposing the HCR initiation sequence on the SiO 2 NPs. This triggers HCR, resulting in the formation of a long double-stranded DNA polymer. The addition of SYBR Green I generates the fluorescent signal output. The feasibility and optimization of the method were validated through a series of experiments, which revealed a linear detection range from 10 −16 to 10 −12 g/mL and an ultra-low detection limit of 6.5448 × 10 −17 g/mL. The method demonstrates exceptional selectivity and anti-interference performance, remaining unaffected by common interfering toxins. Moreover, when applied to real food samples, it exhibited strong agreement with commercial ELISA kits, underscoring its practical potential for food safety monitoring and offering a promising strategy to safeguard public health.