Fe/N-doped carbon dots-based nanozyme with super peroxidase activity, high biocompatibility and antibiofilm ability for food preservation

Bacterial biofilm infections cause about 600 million foodborne illnesses and about 420,000 confirmed deaths annually. However, traditional antibiotics and emerging nanomaterials have the problem of causing bacterial resistance, no catalytic activity and low biocompatibility. Herein, one new antibacterial carbon dots-based nanozyme Fe/N-CDs was developed with antibiofilm ability, excellent peroxidase activity and high biocompatibility. The Fe/N-CDs nanozyme manifested outstanding broad-spectrum antibacterial activity (even multidrug-resistant bacteria) by catalyzing the decomposition of H2O2 to •OH through a peroxide-like reaction (Vmax/Km=1.07×10-6/s), which was 5.35-fold that of horseradish peroxidase (Vmax/Km=0.20×10-6/s). The antibacterial activity increased more than 500-fold after catalysis. The inhibitory capability of Fe/N-CDs nanozyme for Hafinia alvei biofilm was up to 80.2% of by inhibiting extracellular polymeric substances, total protein, AKP enzyme and ATPase. Notably, no obvious cytotoxicity and development of bacteria resistance were observed after co-culturing with the Fe/N-CDs nanozyme. Furthermore, the fresh test results demonstrated that the Fe/N-CDs nanozyme could effectively extend the shelf life of salmon for 3–6 days. These findings indicated that nanozyme could be used to extend the shelf life of food. What's more, this antibiofilm Fe/N-CDs nanozyme provides the potential idea for developing carbon-based nanomaterials with catalytic activity and prevention of bacterial infections in food preservation.