Na/N doped carbon dot nanozymes with enhanced peroxidase activity for antimicrobial food preservation

Annually, up to 25 % of food globally spoils due to microbial pollution. Traditional antibacterial nanomaterials had issues like high dosage, lacked of catalytic activity, and instability. Therefore, Na/N-doping carbon dots nanozymes (Na/N-CDs nanozymes) was developed to fight spoilage organisms. The structural stability of Na/N-CDs nanozymes was enhanced due to the change of lattice structure. Na/N-doping with the peroxidase-mimetic activity was 4.3 times higher than reported HRP activity. It showed strong antimicrobial activity by catalyzing H₂O₂ into ROS, with a MIC of 0.03 mg·mL^-1. And the catalytic activity was over 32 times higher than precursor substances. In contrast, Fe and Cu-doping CDs with a MIC of 0.5 mg·mL^-1 had no nanozyme activity. The results of antibacterial and spoilage assays showed that Na/N-CDs nanozymes antibacteria by damaging cell membranes, degrading DNA, and inhibiting key enzymes, thereby extending the shelf life of salmon fillets by 3 days, indicating potential in aquatic product preservation.