Fluorescent sensing of iron in food and antibacterial actions using rapid synthetic orange-emitting gold nanoclusters

Given the profound significance of tracing Fe 3 + in the environment and food, a fluorescent method for monitoring Fe 3+ by gold nanoclusters (MN-AuNCs) as the sensor was proposed in this work. The MN-AuNCs were prepared via a rapid procedure within 15 min utilizing DL-methionine (Met) and N-acetyl-L-cysteine (NAC) as dual ligands. Meanwhile, the introduction of NAC significantly enhanced the fluorescence quantum yield (QY=13.6 %), 1.5 times that of Met-AuNCs. The MN-AuNCs exhibited high sensitivity and selectivity towards Fe 3+ , with a detection limit of 83 nM. The portable intelligent method based on Smartphone RGB recognition was innovatively developed for rapid on-site monitoring of Fe 3+ . Notably, the MN-AuNCs also demonstrated significant antibacterial activity, with inhibition rates of up to 95 % against Escherichia coli and Staphylococcus aureus. This sensor integrates multifunctionality, including rapid preparation, highly sensitive detection and antibacterial action, offering a novel effective tool for serving food safety and human healthcare.