Functionalization of hyaluronic acid with a chondroprotective molecule and preparation of sulfonated HA-based materials

In the work of thesis, several aspects of hyaluronic acid chemical modification have been explored. In particular, the polysaccharide has been functionalized with NAPA, an amino acidic derivative of D-glucosamine and N-Acetyl-L-phenylalanine with chondroprotective properties, by means of esterification of the glucuronic unit. Preliminary biological studies on human primary chondrocytes (HPCs) has also been presented. The procedure discussed so far represents an innovative and fascinating method for the linkage of a glucosamine derivative to hyaluronic acid that could be useful also in the case of other GlcN-based products. The new HA bioconjugates could gain high relevance as injectable treatments against osteoarthritic disorders. An insight on racemization mechanism that occurs for N-acetylated amino acid was also conducted. In addition, hyaluronic acid was subjected to sulfonation in water. Two sulfonating agents, such as Tau and Bes, were reacted in order to synthetized soluble HA-SO3H derivatives and 3D hydrogels enriched in polar sulfonic groups. Sulfonated polymer demonstrated to have tunable properties depending upon reaction conditions and showed to be promising HA-based materials for biomedical applications.