Uncontrolled bleeding from traumatic injury remains the leading cause of preventable death with loss of balance between blood clotting (coagulation) and blood clot breakdown (fibrinolysis). A major limitation of existing hemostatic agents is that they require a functioning clotting system to control the bleeding and are largely based on gauze delivery scaffolds. Herein, a novel rapid wound sealant, composed of two recombinant snake venom proteins, the procoagulant ecarin, to rapidly initiate blood clotting and the antifibrinolytic textilinin, to prevent blood clot breakdown within a synthetic thermoresponsive hydrogel scaffold is developed. In vitro, it is demonstrated that clotting is rapidly initiated with only nanomolar concentrations of venom protein and clot breakdown is effectively inhibited by textilinin. A stable clot is formed within 60 s compared to normal clot formation in 8 min. In vivo studies reveal that the snake venom hydrogel rapidly controls warfarin-induced bleeding, reducing the bleed volume from 48% to 12% and has demonstrated immune compatibility. A new class of hemostatic agents that achieve formation of rapid and stable blood clots even in the presence of blood thinners is demonstrated here.

Fibrin is the provisional matrix formed after injury, setting the trajectory for the subsequent stages of wound healing. It is commonly used as a wound sealant and a natural hydrogel for three-dimensional (3D) biophysical studies. However, the traditional thrombin-driven fibrin systems are poorly controlled. Therefore, the precise roles of fibrin’s biophysical properties on fibroblast functions, which underlie healing outcomes, are unknown. Here, we establish a snake venom-controlled fibrin system with precisely and independently tuned architectural and mechanical properties. Employing this defined system, we show that fibrin architecture influences fibroblast survival, spreading phenotype, and differentiation. A fine fibrin architecture is a key prerequisite for fibroblast differentiation, while a coarse architecture induces cell loss and disengages fibroblast’s sensitivity towards TGF-β1. Our results demonstrate that snake venom-controlled fibrin can precisely control fibroblast differentiation. Applying these biophysical principles to fibrin sealants has translational significance in regenerative medicine and tissue engineering.

Fibrin is commonly used as a natural hydrogel for three-dimensional (3D) cell culture but is poorly defined. We demonstrate a novel snake venom-controlled fibrin system with tunable architectural and mechanical properties. Employing the snake venom-derived protein ecarin, which rapidly activates the thrombin precursor prothrombin, we establish a tunable fibrin system with a broader range of pore sizes, compared to the existing thrombin-initiated system. By controlling the coagulation factor XIII (FXIII)-induced crosslinking, the mechanical properties are precisely tuned. This fibrin system allows independent control of pore size (1–13 μm) and stiffness (0.2–1 kPa), providing a defined platform for biophysical studies. We show that fibrin architecture influences fibroblast survival, spreading phenotype, and differentiation. A fine fibrin architecture is a key prerequisite for fibroblast differentiation, whilst a coarse architecture induces cell loss and disengages fibroblast’s sensitivity towards TGF-β1. These results have biophysical and translational implications for regenerative medicine and tissue engineering.