Novel ultrafine Pt@Fe-MIL-101 nanozyme enables robust aflatoxin B1 immunoassay in diverse marine and agricultural systems.

BACKGROUND

Aflatoxin B1 (AFB1) stands among the most toxic naturally occurring substances, with its acute toxicity characterized by the induction of acute hepatic necrosis, hemorrhage, and even fatal outcomes, thereby posing a profound threat to human health. Contamination of AFB1 in food commodities can arise at multiple stages throughout the production cycle, including cultivation, storage, and processing. This contamination cascade permeates the entire food supply chain, encompassing primary agricultural products as well as a diverse range of processed food items. Consequently, the development of AFB1 detection methods featuring high sensitivity and robust adaptability is imperative.

RESULTS

We present a marine-adaptive nanozyme-linked immunosorbent assay (NLISA) using ultrafine platinum-loaded Fe-MIL-101 (UP-PT101) as a peroxidase mimic. Optimized synthesis yielded Fe-MIL-101 with ultrafine particles (61.06 nm) and integrated Pt nanoparticles, achieving enhanced peroxidase-like activity (17.33 U/mg) and stability under seawater-like high-salinity/alkaline conditions. Pt-Fe synergy increased reactive oxygen species generation, enabling efficient catalysis, as demonstrated by electron spin resonance and kinetic analyses. A nanozyme-based immunoprobe was fabricated via the modification of AFB1 antibodies onto the surface of UP-PT101, which allows for the rapid and accurate recognition of AFB1. The one-step NLISA established using this immunoprobe exhibits a detection limit of 0.0671 ng/mL for aflatoxin B1 (AFB1) with a detection duration of 75 min, accompanied by a broad linear range (0.1-3.33 ng/mL) and high specificity. When applied to corn, feed, seawater, and marine organisms, the method yielded recovery rates of 79.75-116.78 %, demonstrating robustness in complex matrices.

SIGNIFICANCE: This Metal-organic framework (MOF)-based nanozyme design, featuring high stability, superior catalytic activity, and facile modifiability, has advanced the application of field-deployable rapid monitoring technologies for AFB1 in food supply chains. Integrating environmental adaptability with ultra-sensitivity, this design exhibits promising potential in safeguarding the safety of agricultural products, feeds, and seafood.