Development of a ratiometric fluorescence immunoassay based on manganese dioxide nanosheets for the detection of T-2 toxin

Background T-2 toxin is a highly toxic mycotoxin that poses serious risks to food safety and human health. There is an urgent need for sensitive, selective, and reliable analytical methods for its detection in complex food matrices. Methods We developed a novel ratiometric fluorescence immunoassay based on gold nanoparticles encapsulated in manganese dioxide nanosheets (AuNP@MnO₂), which exhibit intrinsic oxidase-like activity. The assay utilizes dual-emission fluorescence (at 430 nm and 570 nm) and quantifies T-2 toxin by measuring the fluorescence intensity ratio (F₄₃₀/F₅₇₀), thereby minimizing environmental and instrumental variability. Results The method demonstrated excellent linearity over a wide concentration range (0.082–60.00 ng/mL) with a low detection limit of 0.068 ng/mL. High specificity was achieved, showing negligible cross-reactivity against common mycotoxins such as aflatoxin B₁, zearalenone, fumonisin B₁, ochratoxin A, and deoxynivalenol. In spiked corn samples, recoveries ranged from 76.94% to 99.48%, confirming good accuracy, stability, and reproducibility. Conclusion This ratiometric immunoassay significantly enhances detection precision by self-calibrating through an internal fluorescence reference. Its simplicity, sensitivity, and robustness in real food samples make it a promising tool for rapid and reliable monitoring of T-2 toxin in food safety applications.