Physically cross-linked chitosan-based hydrogels for tissue engineering applications: A state-of-the-art review

[Display omitted] •Physical chitosan hydrogels are easily produced.•Chitosan hydrogels are widely used as scaffolds for tissue engineering.•Physical chitosan hydrogels are biocompatible.•Cells can proliferate and adhere into physical chitosan hydrogels. Physically cross-linked hydrogels are used as scaffolds in tissue engineering applications because they are easily produced and avoid the potential toxicity produced by chemical cross-linkers. The physical hydrogels' formation involves several physical interactions as molecular entanglements, hydrogen bonding, ionic, and hydrophobic interactions. Chitosan is a cationic, non-toxic, biocompatible, and biodegradable polysaccharide obtained by chitin's deacetylation and is used to produce physical hydrogels. This manuscript presents a review of the progress in the fabrication of physically cross-linked chitosan hydrogels for tissue engineering applications. The different crosslinking methods used to produce physically cross-linked chitosan hydrogels, their physicochemical and biological properties are also summarized. This review will contribute to a better understanding of the physically crosslinked chitosan hydrogels as potential biomaterials for tissue engineering applications.