A Review of Hydrogels, Their Properties and Applications in Medicine

A hydrogel is a water-insoluble three-dimensional polymer network that has the ability to absorb body fluids in a biological environment. Such a polymer network is formed through chemical crosslinking mechanisms such as optical polymerization, enzymatic reactions and physical crosslinking such as temperature and pH dependent processes and ionic crosslinking. Physical hydrogels are formed through weak secondary force and chemical hydrogels are formed by covalent forces. Various polymers of natural and synthetic origin are used to make hydrogels. Swelling, mechanical properties and biological properties are among the most important properties of hydrogels, each of which can affect the structure and morphology of the hydrogel. Due to its structure similar to the extracellular matrix (ECM) and its ability to absorb water, hydrogen is used in various medical applications such as tissue engineering, contact lenses, wound dressings, and release of therapeutic agents. Hydrogels, types of hydrogels, their properties and applications in medicine are discussed.