Collagen-Based Scaffolds for Potential Application of Heart Valve Tissue Engineering

Collagen, glycosaminoglycans and elastin are the major components of heart valves. This work examines the roles of the composition of the collagen-based scaffolds on the microstructures, mechanical properties, and bioactivities. Scaffolds (with up to 80% elastin or 50% chondroitin-4-sulfate) were prepared by freeze drying suspensions of various compositions. The as-prepared scaffolds had mean pore sizes ranging from 115.6 μm to 187.6 μm. Mechanical characterizations showed that the scaffolds behaved as elastomers, and their characteristic mechanical properties were also dependent on the composition. The tensile, compressive, and bending modulus ranged from 39.8 ± 8.8 kPa, 10.2 ± 1.6 kPa, and 25.4 ± 5.1 kPa to 344.6 ± 42.6, 28.3 ± 4.6 kPa, and 78.3 ± 9.7 kPa, respectively. Cardiosphere derived cells were cultured on the scaffolds, and exhibited significant proliferation throughout the course of the experiment. Depending on the precise composition of the scaffold, chondroitin-4-sulfate increased the proliferation rate of the cells while elastin lowered it. The native heart valve has a tri-layer structure with the layers having compositions similar to those used in this study. Thus, the findings from this study will have implications on how to fabricate a more successful scaffold for tissue engineering heart valves.