A Smart Solution for Tissue Engineering Applications

Gelatine, which is produced by collagen partial hydrolysis, has been largely used in the biomedical field for a wide variety of applications, which are ranging from drug delivery to wound healing. Its spread depends strongly on its biocompatibility: this natural polymer is indeed non-toxic, non-carcinogenic, non-immunogenic, enzymatically degradable and bioresorbable. In the biomedical field gelatine is mostly used as highly concentrated hydrogel (with a melting point above 43 °C - 45 °C) or cross-linked. This work investigated the use of uncross-linked gelatine hydrogels, with a melting temperature in the physiological range, for different biomedical applications. Firstly, it was studied the possibility to produce a solid hydrogel to use as easily removable wound dressing. Once applied to a wound, this patch keeps a moist environment in order to improve the regeneration, while releasing drugs or bioactive factors that it could be preloaded of. Moreover, it can be easily removed, without damages to the wound site and the newly formed tissue, by washing with warm sterile water (37 °C - 39 °C). Secondly, the gelatine material was investigated as substrate for the so-named cell sheet engineering. With our procedure cell sheets can be grown on the gelatine gel and, successively, they can be integrally transferred to a different surface, with gelatine being removed by melting at 37 °C, without any proteolytic enzyme. The gelatine sheet supporting cells, differently from the “Okano” cell sheet method, could be also directly implanted in-vivo without any need for removal, due to the gentle melting of the gelatine sheet after implantation. Thirdly, gelatine gels were used as depot to release pro-angiogenic factors in-vivo. Due to their ability to absorb aqueous solutions and release them while dissolving / degrading, gelatine gels were loaded with Amniotic Fluid Stem Cells Conditioned Medium and used to evaluate the effect of grow factors in a model of ischemic fasciocutaneous flap. Additionally, in order to evaluate the in-vivo degradation rate of gelatine gels loaded with Platelet Rich Plasma, a preliminary test was performed. The results of this test suggested the possibility to employ the gel films as antiadhesive membranes in surgery.