Figure 2: Spatial structure of hyaluronic acid (HA). HA is composed of alternating D-glucuronic acid and D-N-acetylglucosamine moieties, linked together via alternating β-1,4 and β-1,3 glycosidic bonds. The number of repeating disaccharide units (n) can be up to 25000, and each unit has a molecular weight of 401g/mol. The arrows schematize the functional groups that can be used for performing chemical modifications (e.g. addition of a linker).