D-shaped optical fiber lossy mode resonance biosensor for label-free detection of aflatoxin B1.

Aflatoxin B1 (AFB1) is a highly toxic mycotoxin that poses a serious threat to food safety and human health. To achieve rapid, sensitive and specific detection of AFB1, a label-free D-shaped optical fiber sensor based on lossy mode resonance (LMR) was developed in this study. The sensor was fabricated by depositing a SnO2 thin film on the polished surface of a D-shaped optical fiber as the LMR sensitive layer and immobilizing anti-AFB1 antibodies on the SnO2 surface to construct a specific biorecognition interface. The specific binding between AFB1 in the sample and the immobilized anti-AFB1 antibodies causes a change in the effective refractive index (RI) on the fiber surface, thereby causing variation in transmission spectrum. Experimental results show that the fabricated sensor exhibits a good response to AFB1 in the concentration range of 0.1-100 ng/mL with excellent specificity. The sensor's limit of detection (LOD) was approximately 0.071 ng/mL. In addition, the proposed D-shaped optical fiber LMR sensor was successfully applied to the detection of AFB1 in real food samples such as peanuts, corn, wheat, and millet, which provided a promising approach for the rapid and sensitive detection of AFB1 in food and agricultural samples, with broad application prospects in food safety supervision.