Antibacterial properties of folic acid-based hydrogel loaded with CeCDs and its potential application in food preservation

The development of novel preservation techniques capable of food safety and nutrition retention has received extensive attention. Herein, a biocompatible and biodegradable composite folate/zinc supramolecular hydrogel loaded with Ce-doped carbon dots (named FZCC hydrogel) has been fabricated. This hydrogel was synthesized through hydrogen bonds or metal-ligand coordination and held the advantages of superior antibacterial properties, self-healing properties, and washability. Particularly, CeCDs in the hydrogel possessed photodynamic capabilities under white light irradiation, endowing broad antibacterial ability against both Gram-positive and Gram-negative bacteria. The growth inhibition rate reached up to 83.98 % and 80.30 % for S. aureus and E. coli. Moreover, the hydrogels can release high concentrations of Zn²⁺ over 15 days, resulting in a sustained antimicrobial effect. The application of FZCC hydrogel to pakchoi cabbages, apples, and cooked meat can effectively prolong the shelf life and ensure food quality by controlling microbial contaminations, providing great potential for designing sustainable active food packaging materials.