Click chemistry is not a single specific reaction, but describes ways of generating products following examples in nature. Click reactions occur in one pot, are not disturbed by water, generate minimal and inoffensive byproducts, and are characterized by a high thermodynamic driving force that drives the reaction quickly and irreversibly to high yield of a single reaction product. Therefore, since over 15 years it has become a very useful bio-orthogonal method to prepare chemical cross-linked biopolymer-based hydrogel in presence of e.g. growth factors, live cells or in-vivo. Biopolymers are renewable and non-toxicity, providing a myriad of potential backbone’s toolboxes for hydrogel design. The goal of this review is to summarize recent advances in the development of click chemistry based biopolymeric hydrogels and their applications in regenerative medicine. In particular, various click chemistry approaches including copper-catalyzed azide-alkyne cycloaddition reaction, copper-free click reaction (e.g. Diels-Alder reaction, strain-promoted azide-alkyne cycloaddition reaction, radical mediated thiol-ene reaction, and oxime-forming reaction), and pseudo-click reaction (e.g. thiol-Michael addition reaction and Schiff base reaction) are highlighted in the first part. In addition, numerous biopolymers including proteins (e.g. collagen, gelatin, silk, and mucin), polysaccharides (e.g. hyaluronic acid, alginate, dextran, and chitosan) and polynucleotides (e.g. DNA), are discussed. Finally, the biopolymeric hydrogels cross-linked by click chemistry intend for regeneration of skin, bone, spinal cord, cartilage, and cornea are treated. This article provides new insights for readers in terms of the design of regenerative medicine used biopolymeric hydrogels based on click chemistry reactions.© 2020 IOP Publishing Ltd.
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