Volumetric 3D Printing and Melt-Electrowriting to Fabricate Implantable Reinforced Cardiac Tissue Patches

Cardiac patches for repairing myocardial defects require mechanically stable materials that prevent bleeding and can be implanted via suturing. The current clinical standard, bovine pericardial patches (BPPs), serve this purpose but do not degrade or integrate with the myocardium, limiting their long-term effectiveness. Therefore, we have developed the Reinforced engineered Cardiac tissue Patch (RCPatch). This multimaterial patch consists of a stiffness-tuned, cardiomyocyte-infiltrated 3D metamaterial and a suturable, hydrogel-infiltrated mesh to reduce permeability and bleeding. We first designed and computationally optimized anisotropic metamaterials using a generative modelling approach and fabricated them from biodegradable poly(ε-caprolactone) (PCL) via volumetric 3D printing (VP). The metamaterial supported the infiltration of cardiomyocytes, which maintained cell viability and contractility in vitro. In a second step, we enhanced implantability and reduced blood permeability through the patch by combining a melt-electrowritten (MEW) mesh with a fibrin hydrogel. Finally, in an acute large animal trial, the RCPatch was used on an induced myocardial defect, where it withstood intraventricular blood pressure and enabled partial hemodynamic recovery. Our findings establish a scalable framework for fabricating cardiac tissue patches that integrate mechanical reinforcement with biological function, offering a surgically implantable, and potentially regenerative solution for intraventricular myocardial repair.