Synthetic implants made by traditional fabrication routes are not patient specific and rarely match the performance of their biological counterparts. We present an additive manufacturing approach for the digital fabrication of tissue-like aortic heart valves featuring customizable geometry and leaflet architectures that resemble those of native valve tissue. Using biocompatible silicones with tunable mechanical properties, heart valves were fabricated by combining spray and extrusion-based additive manufacturing processes. Computer simulations showed that bioinspired leaflet architectures strongly affect the stress distribution throughout the valves, minimizing stresses on the leaflet during a cardiac cycle. Our computational analysis was complemented by in vitro experiments in a pulse duplicator to demonstrate the outstanding hemodynamic performance of the printed heart valves under physiological pressure cycles. The ability to fabricate synthetic implants with tailored designs at multiple length scales is a key contribution toward the digital fabrication of functional implants that perform on par with native body parts. Current heart valve solutions are expensive and labor intensive to manufacture, have relatively short life spans, contain animal-derived tissue or metallic elements that require immunosuppression or antithrombogenic drugs, and tend not to fit perfectly into the patient's aorta. As such, the number of patients who can receive such replacements is limited. Heart valves customized to fit the anatomy of the patient, match the softness of surrounding tissue, and adapt to the pathology and growth of diseased host tissue represent the next frontier in treatment. Using silicone valves as a model system, we additively manufactured patient-specific, bioinspired designs, effective for in vitro disease modeling and physical simulators. Furthermore, the technology we demonstrate offers a unique potential to create tissue-engineered constructs that closely resemble the architecture and functionality of their biological counterparts, providing mechanical cues to induce the controlled growth of cells. Here we present a multi-material additive manufacturing approach for fabricating personalized polymeric aortic heart valves and surrounding vasculature, derived from a patient's CT data. The valves feature geometries and fiber-reinforced leaflet architectures that resemble those of native valve tissue, along with materials that match the hardness and modulus of specific features. The designs are first simulated to predict the stresses and deformations in the valve, and subsequently the fabricated valves are tested in vitro to show excellent hydrodynamic properties.
Coulter, F. B., Schaffner, M., Faber, J. A., Rafsanjani, A., Smith, R., Appa, H., … Studart, A. R. (2019). Bioinspired Heart Valve Prosthesis Made by Silicone Additive Manufacturing. Matter, 1(1), 266–279. https://doi.org/10.1016/j.matt.2019.05.013