Biocompatible, Biodegradable, and Antimicrobial Food Packaging Film from Polylactic Acid and Biogenic Vaterite
CaCO3-Ag Hybrid

Developing biocompatible and biodegradable materials for food packaging is
crucial for addressing environmental concerns and ensuring food safety. In this study, we
present a novel food packaging film composed of poly(lactic acid) (PLA) and biogenic
vaterite CaCO3-Ag hybrid microspheres. A non-solution technique was employed to
prepare these films, ensuring the sustainability and simplicity of the production process. Xray
diffraction and infrared spectroscopy analyses confirmed the stability and compatibility
of the vaterite CaCO3-Ag microspheres within the PLA matrix. Cytotoxicity tests using
human dermal fibroblast cells demonstrated complete biocompatibility of the films, even
at high concentrations. Antimicrobial efficacy was assessed through minimum inhibitory
concentration (MIC) testing, which demonstrated that PLA film containing 7 wt% vaterite CaCO3-Ag hybrids effectively inhibited both gram-positive and gram-negative bacteria at concentrations as low as ≤0.067 g/mL. Mechanical testing showed that the modulus and strength of PLA film increased significantly with the embedding of 5 wt% of vaterite CaCO3-Ag hybrid, reaching a maximum of 5.63 ± 1.51 GPa and 48.07 ± 13.81 MPa, respectively. Thermal analysis indicated improved thermal stability with the addition of the  microspheres. Synchrotron X-ray absorption spectroscopy confirmed the stability of the vaterite structure and the presence of both Ag0 and Ag+ species after embedding in PLA matrix. The composite films exhibited improved oxygen and water vapor barrier properties, making them suitable for packaging  applications. These findings highlight the potential of PLA-vaterite CaCO3-Ag hybrid films as sustainable and effective food packaging materials.