STABILITY OF THE GELS BASED ON TYPE I COLLAGEN AND HYALURONIC ACID
Development of hyaluronic acid (HA) supplemented biomaterials for regenerative medicine is complicated with easy water solubility of HA. It results in decreased stability of HA-based scaffolds that, consequently, initiated search for crosslinking techniques intended to retain HA within a scaffold. In this study, gels composed of type I collagen and native high molecular weight HA were prepared and their stability in buffer solutions has been evaluated. Fibronectin and human dermal fibroblasts were incorporated into gels as biological linkages for HA instead of chemical agents. Gel stability was estimated based on HA diffusion toward a buffer solution. In addition, HA and HA-supplemented gels resistance to fetal calf serum (FSC) as a part of cultural media for fibroblasts has been studied and no degradation of HA by serum hyaluronidase has been detected under the experimental conditions. The results showed that HA diffuses from collagen gels within 1-3 days. Neither fibronectin nor fibroblasts added separately prevent HA diffusion. But if gels were inoculated with fibroblasts together with fibronectin, more HA was left in the gels according to alcian blue staining. Agarose gel electrophoresis has shown that conditioned media collected from such gels are enriched with HA that differs from the initial one in that it contains a new portion of HA with higher molecular weight. It is concluded that HA-supplemented collagen gels are not stable in buffer solutions but fibroblasts incorporated into such gels synthesize significant amount of HA under the influence of fibronectin and partly compensate the loss of HA due to diffusion.