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

Synthetic materials that mimic the biomechanical and functional response of vascular tissues have applications in medical device testing and surgical training. 3D printing has emerged as a key technology to build complex patient-specific anatomical models with multiple materials to mimic a range of tissue types. However, the capability of 3D printing materials to replicate the mechanical and functional response of native vascular tissues is not clear. The primary goal of this study was to compare the biomechanical response of synthetic 3D printed and polymeric materials against native aortic tissues. Toward this goal, tissue samples from the inner and outer curvature of ascending aorta were obtained from 20 healthy aortic donors. Bi-axial testing was performed on native aortic tissues, Stratasys TissueMatrix series, and silicone samples (Gluck Medical, Soul, Korea). Adult and pediatric aortic phantom with semilunar valves were 3D printed with TissueMatrix materials to perform functional testing. Our findings demonstrated that the elastic modulus of the 3D printed TissueMatrix materials was significantly higher than native aortic tissues at low tangent and high tangent modulus while no significant differences were found for silicone. Mean transvalvular pressure gradients in 3D printed aortic phantoms ranged from 3.5 mmHg to 6 mmHg for Reynolds number ranging from 2000 to 3500, respectively and increased to 25 mmHg at Reynolds number of 7000. 3D printed valves remained intact without fracture or tear even at high Reynolds number. Our work highlights that 3D printed materials are stiffer compared to native tissues with functional responses that resemble stiff native valves. Future work should focus on developing more compliant material mixtures that could ultimately support in device simulations and procedural planning.