Polymer conjugates

Natural-origin bio-polymers used as carriers include proteins (albumin, transferrin, lipoproteins, silk fibroin, collagen, keratin) and polysaccharides (chitosan, cyclodextrin, hyaluronic acid, heparin and pectin). Biomacromolecule-based drug carriers are nontoxic, non-immunogenic and have high drug loading content, good biocompatibility and targeting ability.Biomacromolecule-based carriers have been reported in the form of prodrugs, drug conjugates, nanoparticles, microcapsules, hydrogels and tissue engineering scaffolds.Furthermore, the hydroxyl, amine and carboxyl groups on the chains of these biomacromolecules can be utilized for chemical modification, making them of great significance in biomedical field.Recently there has been a growing interest in bio-polymer conjugation with biologically active components. Their good biocompatibility, predictable degradation rates, and good elasticity make them similar to those of native cartilage. Various polysaccharides including hyaluronic acid, chitosan, dextran, gelatin, pectin, cellulose, and chondroitin sulfates have been derivatized to form the hydrogels.