Construction and Advanced Utilization of Self-Assembled and Scale-Down Chitin Nanofibers for Polymer Composite Design

This review provides a comprehensive overview of recent progress in chitin-based nanomaterials and their composite engineering. Particular focus is placed on techniques for constructing self-assembled chitin nanofibers (ChNFs) with tightly bundled fibrillar structures, as well as strategies for fabricating composites in which the ChNFs serve as reinforcing components, combined with natural polymeric matrices. In addition, high-crystalline scaled-down (SD-)ChNFs were fabricated through partial deacetylation of the ChNFs, followed by electrostatic repulsive disassembly of the abovementioned bundled fibrils in aqueous acetic acid, which were further used to reinforce composites comprising the other polysaccharides. Mixing the SD-ChNFs with low-crystalline chitin substrates further enabled the fabrication of all-chitin composites (AChCs) that exploit crystallinity contrast to achieve enhanced tensile strength. Moreover, the AChC films exhibited high cell-adhesive properties and promoted the formation of three-dimensional cell-networks, highlighting their potential for biomedical applications.