Design and Prototyping of an Optically Clear Mechanical Heart Valve Out of Sylgard-184 Using 3D Printed Mold

Non-physiological flow caused by mechanical heart valves (MHVs) increases risk of clot formation in patients, requiring lifetime anticoagulant drug therapy. Although particle image velocimetry (PIV) enables flow studies, research on flow patterns in key locations such as the hinge region is limited due to obstruction by the valve housing. Developing optically clear valves is essential to observe and analyze non-physiological flow in these key areas, and ultimately, design MHVs with minimal clotting risk. The goal of our research is to produce an optically clear heart valve and test section out of Sylgard-184, as well as a liquid with matching refractive index, that can be used with PIV to observe flow in the hinge region of the MHV. We designed and developed methodology to 3D print molds for silicone parts out of polyvinyl butyral (PVB), utilizing isopropyl alcohol (IPA) smoothing to improve surface finish. Using these molds, we created a valve and test section out of Sylgard-184 with suitable surface finish. We also identified a liquid composition of water, glycerol and sodium iodide with a matching refractive index. We will be conducting distortion testing to confirm that the system is suitable for use with PIV analysis using the mock circulation loop. Based on our process and models, future groups will be able to rapidly prototype new heart valve designs for PIV testing using materials available in the lab, supporting future innovation in MHV design.