Evaluation of anisotropic silk sponges containing cardiac ECM for cardiac tissue engineering

Current biomaterials used in cardiac tissue engineering are insufficient due to the lack of pertinent myocardium characteristics like anisotropy and necessary cardiac extracellular matrix (ECM) proteins. In this study, we take advantage silk, a biomaterial, to analyze effects of 0.2 mg/mL, 0.4 mg/ mL or 0.6 mg/mL addition of cardiac ECM to 3% wt/v silk solution prior to scaffold formation. We created 200 μm thick anisotropic and isotropic silk sponges coated with 100 μg/mL collagen I solution and seeded them with cardiac fibroblasts. The anisotropic scaffolds exhibited an increase in cell spreading, adhesion and cell count as opposed to the isotropic scaffolds. Also, 0.6 mg/mL cardiac ECM incorporation shows increased cell number and spreading compared to the 0.2 mg/mL and 0.4 mg/mL cardiac ECM/silk composite scaffolds. Thus, pore architecture and ECM concentration play significant roles in the creation of optimized silk constructs for cardiac tissue engineering.