Facile incorporation of REDV into porous silk fibroin scaffolds for enhancing vascularization of thick tissues

Rapid neovascularization within scaffolds is critical for the regeneration of thick complex tissues. The surface immobilization of peptides and other active molecules have been explored to improve the vascularization capacity of implants. However, the rapid degradation of these molecules, the reaction conditions and cross-linking usually result in decreased vascularization capability. Here, we introduced a temperate, all-aqueous process to achieve bulk porous silk fibroin (SF) scaffolds. A temperature controlled process was used to induce the water stable structure by SF self-assembly. Arg-Glu-Asp-Val (REDV) peptides were added into SF solution and fixed within SF scaffolds during the self-assembly process. The results showed that the functionalized scaffolds markedly promoted the adhesion of endothelial cells in vitro. Moreover, the in vivo studies indicated enhanced cell infiltration in the bulk functionalized SF scaffolds and impressive vascularization at 4 weeks post-implantation. The functionalized scaffolds demonstrated excellent vascularization capability, providing an exciting biomaterial option for thick tissue regeneration.