The effect of alginate, hyaluronate and hyaluronate derivatives biomaterials on synthesis of non-articular chondrocyte extracellular matrix

Cartilage engineering consists of re-constructing functional cartilage by seeding chondrocytes in suitable biomaterials in vitro. The characteristics of neocartilage differ upon the type of biomaterial chosen. This study aims at determining the appropriate scaffold material for articular cartilage reconstruction using non articular chondrocytes harvested from rat sternum. For this purpose, the use of polysaccharide hydrogels such as alginate (AA) and hyaluronic acid (HA) was investigated. Several ratios of AA/HA were used as well as three derivatives obtained by chemical modification of HA (HA-C18, HA-C12(2.3), HA-C12(2.5)-TEG0.5). Sternal chondrocytes were successfully cultured in 3D alginate and alginate/HA scaffolds. HA retention in alginate beads was found to be higher in beads seeded with cells than in beads without cells. HA-C18 improved HA retention in beads but inhibited the chondrocyte synthesis process. Cell proliferation and metabolism were enhanced in all biomaterials when beads were mechanically agitated. Preliminary results have shown that the chondrocyte neo-synthesised matrix had acquired articular characteristics after 21 days culture.