Snake venom-defined fibrin architecture dictates fibroblast survival and differentiation

Abstract

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.