Physicochemical Characteristics and Biomedical Applications of Hydrogels: A Review

Hydrogels are introduced to modem medicine as novel materials suitable for a variety of biomedical applications. Studying hydrogels as novel biomaterials has become a fast-developing and exciting research field during the last two decades. These interesting biomaterials have found a wide range of application including contact lenses, vehicles for drug delivery and scaffold in tissue engineering and protein delivery systems. Traditionally hydrogels are formed by chemical crosslinking of water-soluble polymers or by polymerization of water-soluble monomers. However, these cross-linking methods lack biocompatibility with fragile molecules like pharmaceutical proteins and living cells. In all types of applications, the biocompatibility of hydrogels is the most important factor to be considered. Many newly developed hydrogels are designed to gel spontaneously under physiological conditions. In these systems, hydrogel formation occurs in situ, at the site of injection, without the aid of potentially toxic or denaturizing cross-linking agents. This review paper presents the chemical nature and biomedical applications of hydrogels.