Biomechanical and Functional Response of 3D Printed Materials and Silicone Elastomers Compared to Human Aortic Tissues

This study benchmarked the mechanical and functional fidelity of commercially available soft 3D-printable photopolymers (Stratasys Digital Anatomy TissueMatrix series) and silicone elastomers against native human ascending aortic tissue. Square specimens (14×14 mm) from TissueMatrix myocardium, vessel-wall, and valve-leaflet formulations and silicone elastomers (hardness 0–20) were compared to inner- and outer-curvature aortic samples from 20 donors. Equibiaxial tensile tests quantified low-tangent and high-tangent moduli, and anisotropy between orthogonal directions was assessed. TissueMatrix materials exhibited substantially higher stiffness than human aorta across modulus regimes, whereas highly compliant silicone formulations produced moduli closer to native tissue at low strain. To evaluate functional behavior, adult and pediatric idealized aortic phantoms with semilunar valves were 3D printed using selected TissueMatrix wall/leaflet combinations and tested in a steady-flow mock circulation loop. Transvalvular pressure gradients increased with Reynolds number (≈3.5–6 mmHg from Re 2000–3500; up to ≈25 mmHg at Re 7000), consistent with stiffer/stenotic-like valve behavior, while printed leaflets remained intact over the tested flow conditions. Overall, the work shows current TissueMatrix formulations are mechanically stiffer than native aortic tissue despite producing functional valve motion, and highlights silicone elastomers as closer mechanical matches for vascular tissue compliance.