Synthesis and characterization of water soluble biomimetic chitosans for bone and cartilage tissue regeneration.

Chitosan, a polysaccharide derived from the exoskeleton of crustaceans, insects, the cell walls of fungi, the radulas of mollusks and the internal shells of cephalopods, has been shown to promote osteogenesis. Arginine functionalized chitosan, a water soluble derivative of chitosan, was successfully sulfated with a degree of sulfur incorporation of up to 9% with substitution at the 2-N position. This degree of sulfation replicated those of naturally occurring growth factor binding glycosaminoglycans. Sulfated chitosan-arginine was found to bind and signal fibroblast growth factor 2. Chitosan-arginine promoted an osteogenic phenotype in primary human fetal chondroblasts over a period of 7 days in the absence of osteogenic medium while sulfated chitosan-arginine promoted a chondrogenic phenotype in these same cells. Together these data demonstrate that fine control over progenitor cell phenotype can be achieved in the presence of sulfate modified chitosan-arginine that promotes further investigation and potential development in the future for applications requiring osteo-chondral repair.