Bridging Food Packaging and Biomedical Applications Using Stimuli-Responsive Natural Polymer–Nanoclay Composites

The growing demand for sustainable, high-performance materials has accelerated research into natural polymer–nanoclay composites as alternatives to petroleum-based plastics and conventional biomaterials. Natural polymers such as cellulose, chitosan, and alginate offer biodegradability, biocompatibility, and chemical functionality, but their standalone use is often limited by inadequate mechanical strength, thermal stability, and barrier performance. Incorporation of naturally occurring nanoclays, including montmorillonite and halloysite nanotubes, overcomes these limitations by providing structural reinforcement, enhanced barrier properties, and tunable bioactive delivery capabilities. This review critically examines recent advances in the design, interfacial chemistry, and multifunctional performance of natural polymer–nanoclay composites, with particular emphasis on stimuli-responsive behavior and bioactive loading strategies. Mechanisms governing pH-, temperature-, moisture-, ionic-, and light-responsive responses are discussed in relation to controlled release and adaptive functionality. A comparative perspective highlights how shared material principles are tailored to meet the distinct performance and regulatory requirements of food packaging and biomedical applications, including shelf-life extension, antimicrobial activity, wound healing, and drug delivery. Fabrication approaches, scale-up challenges, and safety and regulatory considerations relevant to both sectors are also addressed. Despite substantial progress, challenges remain in achieving scalable manufacturing, ensuring long-term safety, and minimizing environmental persistence of nanoclay components. Overall, natural polymer–nanoclay composites represent a promising class of multifunctional, sustainable materials capable of bridging food safety and biomedical innovation through rational material design.