Hyaluronic Acid Hydrogel in Therapeutics Delivery and Biomedical Applications

Hyaluronic acid (HA) is a natural polysaccharide containing multiple units of glycosaminoglycan which is naturally produced inside the human body; however, it can be produced synthetically outside the body from bacteria and by extraction from animal tissues. Currently, HA-hydrogel is an emerging novel drug-loading carrier used for loading biological cells and tissues as it serves as an excellent extracellular matrix system and a platform for the growth and proliferation of cells. As HA is a biological substance, it easily overcomes the issue of immunogenicity and exhibits great biocompatibility. HA-hydrogel is chemically modified by grafting different chemical groups to its functional sites (carboxyl group, hydroxyl group, and N-acetyl group) in order to regulate the function for different therapeutic applications. Depending upon the linkage between the polymeric chain, hydrogels can be classified as physical and chemical hydrogel, and on the basis of the polymeric composition classified as homopolymeric hydrogel, copolymeric hydrogel, and multipolymeric hydrogel. HA-hydrogels can generally be formulated by dissolving a specified quantity of HA in water followed by stirring; however, cross-linking agents can be added to enhance the gelling property, stiffness, and mechanical properties of the hydrogel. The biomedical applications of HA-hydrogel encompass targeted cancer drug delivery, vascular tissue engineering, bone tissue engineering, cartilage tissue engineering, and osteoarthritis treatment as regenerative therapy and also serve its role in the treatment of neurodegenerative treatment.