Fundamentals and Biomedical Applications of Smart Hydrogels

Hydrogels are three-dimensional elastic networks containing a large amount of water formed from crosslinked hydrophilic polymer chains, which possess tunable tissue-like physicochemical properties. This chapter thoroughly introduces the definition, classification, formation, properties, and typical representative and biomedical applications of natural and synthetic hydrogels. In detail, the essential features of hydrogels relate to swelling, mechanical strength, rheology, self-healing, and injectability. As biomaterials, biocompatibility, biodegradability, and toxicity properties should be considered preferentially. Then, we expound on several typical hydrogels, such as self-healing hydrogels, injectable hydrogels, and stimuli-responsive hydrogels, including shape memory hydrogels and hydrogel actuators. Eventually, we summarize the major attractive applications of hydrogels in biomedical fields such as contact lenses, hygiene products, drug delivery, tissue engineering, and wound healing.