Protein-based Injectable Smart Hydrogels for Biomedical Applications

Abstract

Proteins are green, renewable biopolymers produced by living organisms, e.g., animals, insects, and plants. Also, they can be extracted from the byproducts or wastes of the food processing industry. Over the last three decades, several proteins have been extracted and employed either alone or in combination with other materials to generate new multifeatured, pH-, heat-, light-, or enzyme-responsive injectable hydrogels. Protein-based smart injectable biomaterials are attractive platforms for the localized, controlled release of therapeutic drugs and cell therapy. They proved their efficiency as biocompatible, porous, tuneable scaffolds with a significant ability to control microbial infections and support the regeneration of injured skin, bone, and cartilage tissues, even in diabetic animal models. Additionally, the inherent advantage of protein over other natural and synthetic polymers is the presence of several reactive sites such as amino, carboxyl, hydroxyl, thiol, and phenolic groups, which can act as reactive sites for chemical modifications and cross-linking for hydrogel development. The characteristic features such as high water content, swellability, and permeability facilitate the transport and diffusion of essential nutrients, and gases provide an extracellular matrix-like environment to promote cell encapsulation and tissue regeneration. In this chapter, we briefly describe the structure, source, and features of common proteins used in the biomedical field. Also, the chapter covers recently published work and presents some cutting-edge approaches for the preparation and application of protein-based smart injectable hydrogels in drug delivery, wound healing and tissue engineering.