High-speed on-demand 3D printed bioresorbable vascular scaffolds

Recent development of the high-resolution Micro-Continuous Liquid Interface Production (μCLIP) process has enabled 3D printing of biomedical devices with micron-scale precision. Despite our recent success in demonstrating fabrication of bioresorbable vascular scaffolds (BVS) via μCLIP, key technical obstacles remain. Specifically, achieving comparable radial stiffness to nitinol stents required strut thickness of 400 μm. Such large struts would negatively affect blood flow through smaller coronary vessels. Low printing speed also made the process impractical for potential on-demand fabrication of patient-specific BVSs. Lack of a systematic optimization strategy capturing the sophisticated process-materials-performance dependencies impedes development of on-demand fabrication of BVSs and other biomedical devices. Herein, we developed a systematic method to optimize the entangled process parameters, such as materials strength/stiffness, exposure dosage, and fabrication speed. A dedicated speed working curve method was developed to calibrate the μCLIP process, which allowed experimental determination of dimensionally-accurate fabrication parameters. Composition of the citric acid-based bioresorbable ink (B-Ink™) was optimized to maximize BVS radial stiffness, allowing scaffold struts at clinically-relevant sizes. Through the described dual optimization, we have successfully fabricated BVSs with radial stiffness comparable to nitinol stents and strut thickness of 150 μm, which is comparable to the ABSORB GT1BVS. Fabrication of 2-cm long BVS with 5 μm, 10 μm, and 15 μm layer slicing can now be accomplished within 26.5, 15.3, and 11.3 min, respectively. The reported process optimization methods and high-speed, high-resolution 3D printing capability demonstrate a promising solution for on-demand fabrication of patient-specific biomedical devices.