Mechanical testing of rubber-like 3D printing materials for cardiovascular modeling applications

Three-dimensional (3D) printing has attracted considerable attention in cardiovascular applications, offering potential in both clinical practice and in vitro studies. Accurate reproduction of cardiovascular structures depends not only on imaging accuracy but also on the mechanical properties of printed materials. This study focuses on the mechanical characterization of a new series of rubber-like materials, the Vessel Wall (VW) series, designed specifically for cardiovascular applications. Six material blends, with increasing stiffness levels, were evaluated through uniaxial and biaxial tensile tests to assess their mechanical behavior and potential suitability for vascular modeling. Results from uniaxial tests showed that the VW₁, VW₂ and VW₃ materials present elastic moduli between 0.7 and 0.9 MPa, within the range of compliant vascular tissues, while the stiffer blends (VW₄-VW₆), with stiffness in the range 1.1-3.2 MPa, may be more suitable for representing pathological or device-interaction scenarios. An overall isotropic behavior was observed, with minimal influence of print orientation on the mechanical response. In biaxial tests, stress correlation between orthogonal directions showed high linearity (R² = 0.97 ± 0.02), confirming the isotropic mechanical behavior of all blends. In conclusion, the VW series offers a tunable and reproducible set of materials, with elastic properties comparable to cardiovascular tissue, although not capturing their complex mechanical behavior. This study provides a practical reference for an informed selection of materials for different cardiovascular modeling scenarios.