Chitosan-Based Biomaterials for Tissue Repair and Regeneration

Tissue repair and regeneration is an interdisciplinary field focusing on development of biological and bioactive substitutes. Chitosan is a natural polysaccharide exhibiting excellent biocompatibility, biodegradability, affinity to biomolecules, and wound-healing activity. It can also be easily modified via chemical and physical reactions to obtain derivatives of various structures, properties, functions, and applications. This paper focuses on chitosan and its derivatives as biomaterials for tissue repair and regeneration. Tuning the structure and properties such as biodegradability, mechanical strength, gelation property, and cell affinity can be achieved through chemical reaction, immobilization of specific ligands such as peptide and sugar molecules, combination with other biomaterials, and chemical or physical crosslinking. To obtain applicable three-dimensional scaffolding materials such as porous sponges, hydrogels, and rods, the formulation and stimuliresponsiveness of this material can also be modified. Moreover, chitosan and its derivatives can function as vectors for delivery of cell growth factors and particularly of functional genes encoding cell growth factors, which are easier to integrate with the formulated materials to obtain scaffolds of higher activity. Recent studies have shown that such scaffolds are of particular importance in mediating the proliferation, migration, and differentiation of stem cells. Finally, integration of chitosan with cell growth factors and associated genes and/or with cells (stem cells) produces chitosan-based biomaterials with applications in repair or regeneration of skin, cartilage, bone, and other tissue.