Tailoring the barrier and biodegradation performance of nanocellulose for sustainable and compostable packaging applications

Background: Conventional petrochemical packaging offers an excellent oxygen and moisture barrier but creates end-of-life problems that threaten ecosystems. Nanocellulose (NC) materials such as cellulose nanocrystals (CNCs), cellulose nanofibrils (CNFs) and bacterial nanocellulose (BNC) are promising biodegradable alternative. It combines high mechanical properties, lightweight structure, abundant surface hydroxyl groups, and intrinsic biodegradability, making it highly suitable for sustainable food packaging. Scope and approach: This critical review analyses around 567 publications (2020-2025) from databases like ScienceDirect, Scopus, Web of Science, and PubMed. We examined the structure-function relationship of nanocellulose for barrier properties, summarized its performance under composting, soil, and aquatic biodegradation conditions, and discussed environmental and toxicological impacts on human and animal health. Life-cycle assessment results and regulatory standards are also reviewed to understand their role in the circular packaging systems. Key findings and conclusion: Nanocellulose-based materials provide competitive barrier performance against gas and moisture while maintaining transparency, low density, and biodegradability across diverse environmental conditions. Environmental assessments reveal minimal ecological risk at realistic exposure levels, and life cycle assessments report notable reductions in carbon footprint and resource use compared to fossil-based alternatives. To fully realize their potential, challenges in scaling up production and harmonizing regulatory frameworks must be addressed. Adopting a safe and sustainable-by-design (SSBD) approach, which integrates safety, functionality, and circularity throughout the material lifecycle, will be essential for guiding innovation and positioning nanocellulose as a key building block in next-generation sustainable packaging.