High-pressure CO2 treatment of cellulose, chitin and chitosan: A mini review and perspective.

High-pressure CO2 (HPCD) technology has emerged as an environmentally sustainable approach for processing natural polymers such as cellulose, chitin, and chitosan. These polymers, valued for their abundance, biodegradability, and renewability compared to petroleum-based materials, provide a promising foundation for green technologies when combined with HPCD. In this mini review, we begin with an overview of the sources and structures of cellulose, chitin, and chitosan, followed by a discussion of the principles of HPCD and its functionality and role in treating these natural polymers. We then review representative examples of HPCD-treated cellulose, chitin, and chitosan, highlighting various applications, including those in biomedical engineering, environmental remediation, and other fields. Finally, we address current challenges, unresolved issues, and offer perspectives on the future opportunities for HPCD-treated cellulose, chitin, chitosan, and their relevant natural resources.