Alginates: The Wonder Molecule and its Gelling Techniques

Alginates are quite abundant in nature since they occur both as a structural component in marine brown algae (Phaeophyceae), and as capsular polysaccharides in soil bacteria. Alginates are established among the most versatile biopolymers used in a wide range of applications. Alginate is a biomaterial that has found ample applications in drug delivery due to its favorable properties, including thickening, gel forming, stabilizing and biocompatibility properties. So far more than 200 different grades of alginates are manufactured. The ability of alginate to form two types of gel dependent on pH, i.e., an acid gel and an ionotropic gel, gives the polymer unique properties compared to neutral macromolecules. Alginate is typically used in the form of a hydrogel in biomedicine, including wound healing, drug delivery and tissue engineering applications. The molecule can be tailor-made for a number of applications. This review article gives a comprehensive overview on its physicochemical properties such as manufacturing, chemistry and gelling technology.