Near-infrared light-responsive mesoporous polydopamine/carvacrol films for synergistic preservation of refrigerated shrimp

The photothermal effect holds considerable promise for applications in food sterilization and preservation. Mesoporous polydopamine (MPDA), a green photothermal material with high drug-loading and sustained-release properties, was loaded with carvacrol (Car) to prepare MPDA-Car nanoparticles, which were incorporated into a PVA/Gel matrix to fabricate a multifunctional film with synergistic photothermal and Car's broad-spectrum antibacterial activity. Near-infrared (NIR) irradiation-induced photothermal effect directly damaged bacterial membranes and triggered controlled Car release from MPDA mesopores, enhancing antibacterial efficacy. Characterization confirmed that uniform MPDA-Car dispersion significantly improved the film's mechanical strength (tensile strength: 22.14 MPa, elongation at break: 218.36%) and reduced water vapor permeability (WVP) by 32.7% compared with the pure PVA/Gel film. The film also exhibited excellent antioxidant capacity (DPPH: 74.4%, ABTS: 77.9%) and potent inhibition against Staphylococcus aureus and Escherichia coli . In Chinese shrimp preservation, the 1.00% PG-MC film mitigated weight loss, retarded TVB-N and TBA accumulation, inhibited pH elevation, and extended shelf life by over 2 days. Notably, MPDA-mediated mild photothermal heating caused no significant degradation of shrimp soluble protein or LOX activity, retaining nutritional quality. This film provides a promising strategy for developing eco-friendly food packaging materials.