Nonlinear Elastic Scaffold Design, Modeling and Fabrication for Soft Tissue Engineering

Biologic soft tissues exhibit nonlinear elastic behavior under physiologic forces. It is widely postulated that within tissue engineering, biomaterial scaffolds should be designed to replicate native tissue behavior. For soft tissue engineering, this implies that scaffolds should be designed to exhibit nonlinear elasticity. However, unlike linear elasticity, there is no single constitutive model for nonlinear elasticity. In this chapter, we discuss candidate strain energy functions that can be used to both model soft tissue behavior and biodegradable elastomer behavior. We further demonstrate how designed pore architecture not only reduces the tangent stiffness of nonlinear elastic biomaterials, but decreases the non14 linearity of such materials in accordance with known upper bounds on effective nonlinear elastic properties. Finally, we demonstrate that nonlinear elastic finite element analysis on porous scaffold unit cell models can be used to predict the effective nonlinear elastic properties of elastomeric scaffolds.