Photoactivated multimodal antimicrobial biopolymer films: synergies, innovations, and sustainable intelligent food packaging

Biopolymer-based food packaging films (FPFs) have emerged as promising sustainable substitutes for petroleum-derived materials, owing to their biodegradability, biocompatibility, and cost-effectiveness. However, their inherent limitations in physicochemical properties necessitate functional enhancements to meet stringent requirements for food preservation. This review systematically investigates the integration of photothermal (PTA), photodynamic (PDI), and photocatalytic (PCA) additives into biopolymer matrices, which synergistically confer light-activated antimicrobial activity, antioxidant effects, and structural reinforcement. We elucidate the underlying mechanisms, focusing on reactive oxygen species (ROS) generation and localized hyperthermia that disrupt microbial integrity. Key advancements include hybrid systems (e.g., PTA/PDI composites, sustained-release platforms, and multifunctional metal–organic frameworks [MOFs]) that achieve > 99% inhibition of pathogens. Material innovations—including curcumin-β-cyclodextrin complexes, polydopamine nanoparticles, and carbon nanotube hybrids—address critical challenges (e.g., photosensitizer hydrophobicity, nanoparticle aggregation) while enhancing mechanical strength, barrier properties, and controlled release. Photoactivated FPFs further exhibit dual functionality: enabling real-time freshness monitoring via pH-responsive indicators and delaying fruit senescence through ethylene degradation. Emerging strategies combining PDI, PCA, and PTA, alongside light-triggered gaseous antimicrobials, hold promise for next-generation smart packaging. Despite these progress, challenges persist: insufficient light penetration in complex food matrices, potential food quality degradation under prolonged/high-intensity irradiation, and oxygen dependence of ROS generation. Future research should target these limitations to enhance the practicality and safety of light-responsive packaging. This review provides a critical roadmap bridging material science and food technology, facilitating the development of eco-friendly, high-performance biopolymer films for ensuring food safety and extending shelf life.