Surface-Engineered Nanocellulose for Biomedical Applications: Structure–function Perspectives

Cellulose, an abundant and sustainable biopolymer, has emerged as a versatile platform for advanced biomedical nanomaterials. Nanocellulose is obtained through integrated pretreatment and mechanical processes, including chemical, enzymatic, and oxidation-based strategies that reduce energy consumption and enable controlled structural tuning. The three main forms – cellulose nanofibers (CNF), cellulose nanocrystals (CNC), and bacterial nanocellulose (BNC) – differ in morphology, crystallinity, and production routes, resulting in distinct physicochemical and biological properties. A high density of surface hydroxyl groups allows extensive surface engineering through oxidation, grafting, crosslinking, and biofunctionalization. These modifications are central to tailoring structure–function relationships that govern biocompatibility, mechanical strength, drug loading capacity, and controlled release behaviour. This review provides a focused structure–function perspective on surface-engineered nanocellulose for biomedical applications. Emphasis is placed on drug delivery systems, wound healing materials, tissue engineering scaffolds, antimicrobial platforms, and biosensing technologies. By correlating structural design with biological performance, this work highlights the expanding role of nanocellulose in next-generation biomedical innovations.