Natural polymers-based light-induced hydrogels: Promising biomaterials for biomedical applications

There has been a significant increase in demand for biomaterials over the last decades. According to this fact, the design and development of more efficient and sophisticated biomaterials have attracted a great deal of interest. In this context, natural polymers-based hydrogels have received more attention due to their inherent physicochemical and biological features, as well as numerous biomedical applications (e.g., wound healing, drug delivery, and tissue engineering). Various synthetic approaches, including ester or amide formation, radical polymerization, Michael addition, Schiff-base, and disulfide crosslinking have been introduced for the synthesis of natural polymers-based hydrogels. Amongst, the light-induced radical polymerization (otherwise known as photo-polymerization) has received a considerable attention due to its advantages such as solvent-free, easy and rapid network formation, energy-efficient, fast process, spatial and temporal control, in situ gelling viscoelastic systems in vivo with a minimally invasive manner, and tenability of crosslinking density and matrix stiffness using light intensity, exposure time and the illuminated area. This review article discusses the recent advances of the design, development, as well as numerous biomedical applications of natural polymers-based light-induced hydrogels. In addition, the advantages and disadvantages of light sources (near-infrared (NIR), visible light and ultraviolet (UV)) as well as current status and challenges are discussed. (C) 2020 Elsevier B.V. All rights reserved.