A Recombinant Human\nCollagen and RADA-16 Fusion Protein\nPromotes Hemostasis and Rapid Wound Healing

In this study, we designed a fusion protein, rhCR, by\ncombining\nhuman collagen with the self-assembling peptide RADA-16 using genetic\nengineering technology. The rhCR protein was successfully expressed\nin Pichia pastoris. The rhCR can self-assemble\ninto a three-dimensional nanofiber network under physiological conditions.\nThe lyophilized rhCR sponge exhibited high elasticity modulus and\nstable swelling properties. <i>In vitro</i> experiments\nconfirmed that the rhCR had good biocompatibility and could significantly\npromote the adhesion, proliferation, and migration of fibroblasts\n(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\nhemostatic sponges rapidly formed nanofibers on the ruptured liver\nsurface, activated platelet CD62P, and significantly reduced blood\nloss and bleeding duration compared to the recombinant human collagen\n(rhCol) alone. Furthermore, the rhCR application markedly accelerated\nwound healing in a mouse full-thickness skin defect model, with the\nwound healing rate in the rhCR group being 2.6 times that of the untreated\ngroup and 1.7 times that of the rhCol group on day 6 postinjury. Histological\nand immunofluorescence analyses revealed that the rhCR promoted collagen\ndeposition and epidermal regeneration and improved the quality of\nskin tissue repair by stimulating tissue cells to produce cytokines,\ngrowth factors, and immune factors through immunological regulation.\nThe rhCR fusion protein combines the advantages of collagen and RADA-16,\novercoming the limitations of their separate use in hemostatic and\ntissue engineering applications. This biomaterial and its design idea\nhold promise for a variety of regenerative applications.