Chitosan/zinc oxide (ZnO) nanocomposites: A critical review of emerging multifunctional applications in food preservation and biomedical systems

The increasing uses of petroleum-based materials for food packaging and medical applications raised significant environmental concerns. Researchers and industry stakeholders are actively exploring sustainable alternatives to replace those materials. Chitosan/zinc oxide (ZnO) bio-nanocomposites have emerged as promising alternatives to replace conventional plastics. Chitosan, a biodegradable biopolymer, exhibits exceptional film-forming properties, biocompatibility, and antimicrobial activity for sustainable application. On contrary, it has also certain drawbacks that limit its industrial applications including poor mechanical properties and high sensitivity to humidity. The integration of ZnO nanoparticles addresses these limitations by enhancing their mechanical strength, UV-blocking ability, stability, and functional properties with superior antimicrobial and antioxidant capabilities. This study critically examines past and current research, innovations, and development in chitosan/ ZnO nanocomposites, with a focus on their sources, latest synthesis methods, properties, limitations and potentials applications in the food preservation and biomedical fields. Findings indicate that these nanocomposites can not only extend the shelf life of food products and are used for effective wound treatment, drug delivery, and tissue engineering but also reduces environmental impact. By highlighting recent advancements and future research directions, this review aims to promote the development of sustainable and eco-friendly solutions to address global challenges in food waste and healthcare.