History and Applications of Hydrogels

Hydrogels have existed for more than half century, providing one of \nthe earliest records of crosslinked hydroxyethyl methacrylate (HEMA) \nhydrogels. Today, hydrogelsstill fascinate materialscientists and biomedical \nresearchers and greatstrides have beenmade in terms oftheirformulations \nand applications. As a class of material, hydrogels are unique, they consist \nof a self-supporting, water-swollen three-dimensional (3D) viscoelastic \nnetwork which permitsthe diffusion and attachment of molecules and cells. \nHowever, hydrogels have recently drawn great attention for use in a wide \nvariety of biomedical applicationssuch as cell therapeutics, wound healing, \ncartilage/bone regeneration and the sustained release of drugs. This is due \nto their biocompatibility and the similarity of their physical properties to \nnatural tissue. This review aims to give an overview of the historic and the \nrecent design concept of hydrogels and their several applications based on \nthe old and the most recent publications in this field.