Biomedical applications of hyaluronic acid

Hyaluronic acid (HA), also named hyaluronan, is a high molecular weight polysaccharide found in the body in pericellular matrices, various bodily fluids, and in specialized tissues such as the vitreous humor of the eye and cartilage. Hyaluronic acid possesses both biological activities and physical properties that add to the uniqueness of this ubiquitous polysaccharide. The uniqueness of HA and its importance both biologically and physically apparently accounts for its identical structure when synthesized in bacteria, birds, and mammals. Because of this property, HA has been purified from chickens or bacteria for use as a biomaterial in medical devices in humans or other mammals. Hyaluronic acid is unique because of its viscoelastic and hydrodynamic properties, its assembly into extracellular and pericellular matrices, and its effects on cell signaling. Its use as a biomaterial has been driven largely by its physical properties and viscoelastic behavior. The biological properties of HA and its fragments have largely been ignored in its use as a biomaterial. As HA is more widely used and studied, these properties are becoming increasingly apparent and important in its use in medical devices. (c) 2006 American Chemical Society