Highly efficient cardiac differentiation and maintenance by thrombin-coagulated fibrin hydrogels enriched with decellularized porcine heart extracellular matrix

We provide a blend of cardiac decellularized extracellular matrix (dECM) from porcine ventricular tissue and fibrinogen for the formation of an in-vitro 3D cardiac cell culture model. Rapid and specific coagulation with thrombin allows gentle inclusion of cells while avoiding sedimentation during formation of the dECM-fibrin composite. We show enhanced cardiogenic differentiation in the H9c2 myoblast cell line when using the system in co-culture with Nor-10 fibroblasts. Further enhancement of differentiation efficiency is obtained by 3D embedding. We then proceed with culture of rat neonatal cardiomyocytes in the 3D system. While for H9c2 cells, the collagen content of the dECM is the key factor required for efficient differentiation, the use of dECM-fibrin has specific advantages regarding the culture of neonatal cardiomyocytes. Calcium imaging and analysis of beating motion both indicate the dECM-fibrin composite significantly enhances recovery, frequency, synchrony and maintenance of spontaneous beating, as compared to various controls including matrigel, pure fibrin and collagen I, but also a fibrin-collagen I blend.