A Recombinant Human Collagen and RADA-16 Fusion Protein Promotes Hemostasis and Rapid Wound Healing

In this study, we designed a fusion protein, rhCR, by combining human collagen with the self-assembling peptide RADA-16 using genetic engineering technology. The rhCR protein was successfully expressed in <i>Pichia pastoris</i>. The rhCR can self-assemble into a three-dimensional nanofiber network under physiological conditions. The lyophilized rhCR sponge exhibited high elasticity modulus and stable swelling properties. <i>In vitro</i> experiments confirmed that the rhCR had good biocompatibility and could significantly promote the adhesion, proliferation, and migration of fibroblasts (L929), upregulating the expression of genes such as <i>Vim</i>, <i>Fgf</i>, <i>Vegf</i>, and <i>Tgf-β3</i> in L929 cells. When applied to a mouse liver hemorrhage model, rhCR hemostatic sponges rapidly formed nanofibers on the ruptured liver surface, activated platelet CD62P, and significantly reduced blood loss and bleeding duration compared to the recombinant human collagen (rhCol) alone. Furthermore, the rhCR application markedly accelerated wound healing in a mouse full-thickness skin defect model, with the wound healing rate in the rhCR group being 2.6 times that of the untreated group and 1.7 times that of the rhCol group on day 6 postinjury. Histological and immunofluorescence analyses revealed that the rhCR promoted collagen deposition and epidermal regeneration and improved the quality of skin tissue repair by stimulating tissue cells to produce cytokines, growth factors, and immune factors through immunological regulation. The rhCR fusion protein combines the advantages of collagen and RADA-16, overcoming the limitations of their separate use in hemostatic and tissue engineering applications. This biomaterial and its design idea hold promise for a variety of regenerative applications.