Hyaluronic Acid Based Semi Interpenetrating Materials

To enhance the mechanical performances of hyaluronic acid (HA) without compromising its biological activity, hyaluronic acid has been interpenetrating with a fibrillar collagen scaffold. The semi interpenetrating materials were obtained by mixing HA with different molecular weight and a pepsin solubilized collagen (atelocollagen) solution, and then by inducing collagen fibrillogenesis. Results indicate that molecular weight of hyaluronic Acid significantly influences the mechanical properties of the semi interpenetrating materials and more specifically stronger material results from the use of low molecular weight (LMW) hyaluronic acid. According to the dynamic mechanical data the composite collagen-LMW HA has higher elastic modulus than collagen, whereas the opposite is true for the high molecular weight (HMW) HA. This result highlights the role of specific interactions that occur between collagen and HA during the gel formation in controlling the network mechanical stability. LMW HA may, probably, interact more strongly with collagen during fibrillogenesis process than HMW HA due to the higher mobility of the chains and the weaker homologous interactions. The morphological observations, moreover, showed that LMW HA is intimately interdispersed within the collagen network and completely coated the fibrils, which act as mechanical support.