Chemical Functionalization of Polysaccharides—Towards Biocompatible Hydrogels for Biomedical Applications

Hydrogels have emerged as a highly interdisciplinary topic as they play a significant role for a vast number of applications. They have been studied extensively as materials for contact lenses, wound dressing and as filler material in soft-tissue augmentation, in which classical polymer backbones such as hydroxyethylmethacrylate (HEMA) are typically employed. More recently, polysaccharides have received attention, particularly in the fields of regenerative medicine and tissue engineering, as ideal candidate materials for artificial extracellular matrices (ECM). The polysaccharides of choice are dextran, alginate, chitosan, hyaluronic acid and pullulan and in order to obtain suitable hydrogels from these polysaccharides, controlled chemical functionalization is of critical importance. This short review summarizes recent developments in the chemical derivatization of polysaccharides to pave the way for crosslinking and to decorate individual polysaccharide chains with bioactive ligands. The report covers convergent and divergent protocols for crosslinking, as well strategies for bisfunctionalization of polysaccharides. Additionally, information on biological properties and biomedical applications are covered.