Green CuO/ZnO Nanoparticles: Reducing AFB1 Translocation and Accumulation in Maize

Aflatoxin B1 (AFB1) is a potent carcinogen produced by Aspergillus species that contaminates maize crops, posing severe health risks to humans and animals through dietary exposure. Traditional post-harvest management and chemical interventions are often costly or ineffective at preventing the translocation of soil-borne toxins into the plant during growth. The primary goal of this protocol was to evaluate green-synthesized copper oxide/zinc oxide (CuO/ZnO) hybrid nanoparticles (NPs) as a sustainable pre-harvest soil amendment. The study aimed to determine if these NPs could effectively inhibit the translocation and accumulation of AFB1 within maize tissues, thereby reducing toxin accumulation in edible grains. Using a randomized complete block design across two distinct field sites, maize was grown in soil inoculated with AFB1 or Aspergillus flavus spores and treated with varying concentrations of NPs (0-125 mg/kg). The protocol employed green synthesis with Pleurotus ostreatus substrate to ensure eco-friendliness. Plant tissues were analyzed at different physiological stages using High-Performance Liquid Chromatography (HPLC) to measure AFB1 levels and calculate human and livestock risk assessments. Treatment with 125 mg/kg of green hybrid NPs significantly (p < 0.05) decreased AFB1 concentrations across all growth stages. At the on-campus site, AFB1 was reduced by 68% at the vegetative stage, 82% at flowering, and 76% at maturity compared to the positive control. Crucially, grain AFB1 levels dropped to 6.91 ppb, significantly lowering the estimated daily intake for humans. However, further research is required to evaluate potential nanoparticle residues and long-term toxicity. This method demonstrates that green CuO/ZnO hybrid NPs act as an effective bioremediation agent, preventing the transport of toxins to edible parts of the plant. This approach offers a scalable, environmentally safe strategy to enhance food security and mitigate AFB1 exposure in aflatoxin-prone regions.