Smart Antibacterial Food Packaging Based on MIL-53 (Fe) Functionalized Polylactic Acid Film for pH-Responsive Controlled Release

Due to environmental concerns related to non-biodegradable plastics, there is a high demand for biodegradable films, particularly those that incorporate natural antibacterial agents with long-lasting antimicrobial properties to maintain food quality and meet consumer health needs. This work encapsulated lysozyme in MIL-53 (Fe) microparticles (M@LYZ MPs) and incorporated them into polylactic acid (PLA) polymer (M@L-PLA film) using a solution casting technique. M@LYZ MPs release lysozyme in response to the acidic growth environment of microorganisms. The results showed that (i) incorporating M@LYZ MPs increased the mechanical properties and thermal stability of the film, (ii) the M@L-PLA film had remarkable antibacterial activity, with inhibition rates of 98.07% and 99.15% against E. coli and S. aureus, respectively. And the bacterial viability on M@L-PLA film decreased by more than 92%, indicating a strong anti-adhesion effect, and (iii) the soil degradability rate of M@L-PLA film reached almost 50% in 16 weeks. The incorporating M@LYZ MPs endowed the film with better lysozyme stability, antibacterial and anti-adhesion properties. These pH-responsive lysozyme-release films have great potential for intelligent packaging in food preservation applications. Graphical Abstract: [Figure not available: see fulltext.]