Fe-N-C single-atom nanozyme-linked immunosorbent assay for quantitative detection of aflatoxin B1

Aflatoxin B1 (AFB1) is a prominent food contaminant known for its high toxicity. Rapid, low-cost, and sensitive detection of AFB1 is an urgent demand for food safety risk control. In the traditional enzyme-linked immunosorbent assay (ELISA) method for AFB1 detection, horseradish peroxide (HRP) is high-cost and possesses poor environmental stability. In this study, a direct competitive single-atom nanozymes (SAzymes) -linked immunosorbent assay was developed based on Fe-N-C SAzymes. The proposed methods exhibited excellent sensitivity, rapid detection, fabrication, and low cost. Under the optimal conditions, the limit of detection of the new assay was 3.3 pg mL−1, with a quantitative relationship between 0.0084 and 0.358 ng mL−1. In addition, the developed method presented good recoveries in spiked samples, ranging from 84.50% and 103.75%, with coefficients of variation below 10%. Furthermore, the developed detection method showed good consistency (R2 = 0.9852) with the reference method, liquid chromatography/mass spectrometry (LC-MS/MS). To our knowledge, this is the first report about single-atom nanozymes-based ELISA for AFB1 determination. This work provides a feasible strategy for the rapid and sensitive detection of food contaminants using SAzymes.