Design principles and functionalization strategies of injectable hydrogels based on natural polymers for advanced wound healing

Preformed hydrogel also known as conventional hydrogel has been widely used for wound healing purposes over the past decades. One of the major disadvantages of preformed hydrogel is that they can be applied at the exterior wound surface and fails to distribute in case of irregularly shaped wounds. These disadvantages have led to development of injectable hydrogel system with focus on using natural polymers such as proteins and polysaccharides. The current research flavor is not only injectability but injectability with multifunctionality especially anti-microbial properties. However, developing an injectable hydrogel for wound healing withmultifunctions is complex because of consideration of several design factors such as molecular weight, rheological behavior, gelation characteristics, biocompatibility, surface characteristics, antimicrobial activity and complexity of wound healing process. The objective of this review is to highlight different aspect of design criterion suitably used for developing injectable hydrogel from natural polymers, functionalization strategy and a review of usage of these criterions in current literature.