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<p>Bioresorbable polymeric coronary stents (BCSs) offer transformative potential for cardiovascular therapy by providing temporary vascular support before degrading, yet structural performance and complex processing hinder their clinical translation. Single-shot net-shape fabrication via micro-injection molding (µIM) offers a cost-effective, high-throughput solution with minimal material waste in cleanroom settings. To overcome mold underfilling in high L/t ratio (&gt; 650) geometries, this study introduces a multiphysics computational framework combining finite element analysis for structural validation with computational fluid dynamics for melt-flow simulation. The objective is to optimize BCS designs for mechanical integrity and manufacturability, enabling scalable µIM-based net-shape production. The framework systematically evaluates seven BCS designs, including four CE-marked geometries, two patented novel variants, and one reported design under uniform processing conditions using different grades of PLA. Structural parameters including radial strength, bending resistance, and elastic recoil, were analyzed alongside manufacturability outcomes such as mold-filling efficiency, pressure requirement, and defect formation. Key findings reveals that the manufacturability via µIM depends not only on L/t ratio and gate configuration but also on the detailed geometric profile of the stent. Intricate designs demand prohibitively high injection pressures (~ 1500&#xa0;MPa) due to extremely fine features and impractical profiles which impeding melt propagation, whereas the patented Diamond-4 geometry achieves comparable radial strength, lower elastic recoil, and slightly higher bending stiffness, with complete cavity filling at substantially lower injection pressures and the least shrinkage among all evaluated designs. Coupling structural and melt flow analysis, the methodology links clinical needs like vascular patency and endothelialisation with µIM process challenges including high polymer viscosity, premature solidification, and demolding issues. This dual-validation approach aligns mechanical performance with processing constraints, offering a predictive tool for net-shape fabrication of next-generation polymeric BCS. It minimizes costly experimental trials and accelerates scalable stent development.</p>

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Role of Stent Geometry on Net-Shape Fabrication of Bioresorbable Polymeric Coronary Stent Via Microinjection Molding

  • 期刊论文

  • 发表日期：

    2026年5月4日

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  • Dharmendra K. Tyagi,
  • Dhiraj K. Mahajan

摘要

Bioresorbable polymeric coronary stents (BCSs) offer transformative potential for cardiovascular therapy by providing temporary vascular support before degrading, yet structural performance and complex processing hinder their clinical translation. Single-shot net-shape fabrication via micro-injection molding (µIM) offers a cost-effective, high-throughput solution with minimal material waste in cleanroom settings. To overcome mold underfilling in high L/t ratio (> 650) geometries, this study introduces a multiphysics computational framework combining finite element analysis for structural validation with computational fluid dynamics for melt-flow simulation. The objective is to optimize BCS designs for mechanical integrity and manufacturability, enabling scalable µIM-based net-shape production. The framework systematically evaluates seven BCS designs, including four CE-marked geometries, two patented novel variants, and one reported design under uniform processing conditions using different grades of PLA. Structural parameters including radial strength, bending resistance, and elastic recoil, were analyzed alongside manufacturability outcomes such as mold-filling efficiency, pressure requirement, and defect formation. Key findings reveals that the manufacturability via µIM depends not only on L/t ratio and gate configuration but also on the detailed geometric profile of the stent. Intricate designs demand prohibitively high injection pressures (~ 1500 MPa) due to extremely fine features and impractical profiles which impeding melt propagation, whereas the patented Diamond-4 geometry achieves comparable radial strength, lower elastic recoil, and slightly higher bending stiffness, with complete cavity filling at substantially lower injection pressures and the least shrinkage among all evaluated designs. Coupling structural and melt flow analysis, the methodology links clinical needs like vascular patency and endothelialisation with µIM process challenges including high polymer viscosity, premature solidification, and demolding issues. This dual-validation approach aligns mechanical performance with processing constraints, offering a predictive tool for net-shape fabrication of next-generation polymeric BCS. It minimizes costly experimental trials and accelerates scalable stent development.