In situ forming gel fo wound healing

Purpose: Aim of this work was to engineer injectable polymeric platform, able to undergo reversal thermal gelation at body temperature, to fill the cavities of wounds and release active ingredients in situ with a controlled kinetic. Methods: Polymeric platforms made up of chitosan (CHI) and blends of methylcellulose (MC) with low (~150 kDa) or high (~1*106 Da) molecular weight hyaluronic acid (HA), at different concentration, were prepared. The gelation temperature and viscoelastic properties of the platforms were investigated and optimized by means of rheological analysis. In particular, small amplitude frequency sweep tests were performed to evaluate the dependence of dynamic moduli on frequency. In order to evaluate the gelation temperatures, the viscoelastic parameters were monitored as a function of the temperature from 20°C up to 40°C at a fixed oscillation frequency of 0.01 Hz. In addition, we investigated the effects of the gels on human foreskin foetal fibroblasts (HFFF-2) viability. Results: By varying polymers molecular weight and concentration into the blends, it was possible to obtain an optimized formulation showing a rheological behaviour typical of a viscous solution at 25°C and of a gel at 37°C. In vitro studies showed a good biocompatibility of MC and low molecular weight HA based gels since they did not affect HFFF-2 cells viability. In contrast CHI based as well as high molecular weight HA formulations decreased cell viability. Conclusions: Thermosensitive and biocompatible gels were formulated, with a phase transition temperature near to body temperature, potentially useful for wound healing applications.