Review: the latest advances in biomedical applications of chitosan hydrogel as a powerful natural structure with eye-catching biological properties

Chitosan is one of the natural cationic polymers with unique properties such as non-toxicity, biodegradability, biocompatibility, environmentally friendly that has various biomedical applications. Chitosan-based hydrogels are hydrophilic polymer biomaterials with a three-dimensional cross-linked network structure. The methods of chitosan hydrogels fabricating are categorized into chemically and physically cross-linking between polymer chains. These hydrogels are employed for clinical applications because of their biological and physicochemical features. The most important applications of chitosan hydrogels have been considered in this review. Chitosan hydrogels are applicable in drug delivery due to their ability to control releasing of drugs through pH-responsive and temperature-responsive release approaches and the network structure that can carry drugs. Also, chitosan hydrogels are an excellent choice for wound healing because of their features such as antibacterial, providing moisture and heat in the wound area, biocompatibility, and so forth. Furthermore, swelling capacity, porosity, and mechanical properties make these hydrogels a good candidate as a scaffold for tissue formation. The other applications of chitosan hydrogels in biosensors, protein purification, and dye materials separation from wastewater have been considered in this review. Graphical abstract: [Figure not available: see fulltext.].