ABSTRACT
Polysaccharides are long carbohydrate molecules that contain repeated monosaccharide units joined together by means of glycosidic bonds.1 Polysaccharides are present in a variety of living beings such as in algae as alginate, in plants as pectin and cellulose, in microbes as dextran and xanthan gum, and in animals as chitosan and heparin.2 They may be classied according to their charge: cationic (e.g., chitosan), anionic (e.g., hyaluronic acid, heparin, and alginate), and nonionic (e.g., dextran).1,3
Polysaccharides may be classied by their function4,5 and their composition.6,7 For instance, structural polysaccharides (e.g., cellulose and chitin) provide protection, support, and shape to cells, tissues, organs, and organisms; storage polysaccharides (e.g., starch and dextran) serve as a means to store carbohydrates4,5; and hydrophilic polysaccharides (e.g., hyaluronan) prevent cell dehydration.8 They can be classied according to their composition as homopolysaccharides-composed of a monosaccharide unit (e.g., cellulose, starch, and glycogen)—and heteropolysaccharides composed of two or more monosaccharide units.6,7 An important class of heteropolysaccharides are glycosaminoglycans that are molecules of high molecular weight formed from two or more different types of monosaccharide units, linked by O-glycosidic bond such as hyaluronic acid, heparin, and chondroitin sulfate.9 Glycosaminoglycans (GAGs) are a crucial component of native extracellular matrix (ECM).
