Marine Derived Polysaccharides For Biomedical Applications: Chemical Modification Approaches

Polysaccharides-based biomaterials are an emerging class in several biomedical fields such as tissue regeneration, particularly for cartilage, drug delivery devices and gel-entrapment systems for the immobilization of cells. Important properties of the polysaccharides include controllable biological activity, biodegradability, and their ability to form hydrogels. Most of polysaccharides derive from natural sources; particularly, alginate and chitin, two polysaccharides which have an extensive history of use in medicine, pharmacy and basic sciences, can be easily extracted from marine plants (algae kelp) and crab shells, respectively. Recent re-discovery of polysaccharide-based materials is also attributable to new synthetic routes for their chemical modification, with the aim to promote new biological activities and to modify the final properties of the biomaterial for specific purposes. These synthetic strategies involve also the combination of polysaccharides with other polymers. A review of the more recent research in the field of chemical modification of alginate, chitin and its derivative chitosan is here presented. Moreover, we report as case studies the results of our recent works concerning various different approaches and applications of polysaccharide-based biomaterials, such as the realization of novel composites based on calcium sulphate blended with alginate and with a chemically modified chitosan, the synthesis of novel alginate-poly (ethylene glycol) copolymers, and the development of a family of materials based on alginate and acrylic polymers of potential interest as drug delivery systems.