Novel net-shape manufacturing of bioresorbable coronary stents using micro-injection molding process

The bioresorbable cardiovascular stent (BCS) represents a significant advancement in medical technology, offering temporary support to diseased arteries while eliminating the long-term risks associated with permanent implants. However, traditional fabrication methods involve multiple steps, rendering BCS a costly medical device. To address this challenge, net-shape manufacturing techniques have emerged as a promising approach to streamline production and facilitate mass manufacturing. Micro-injection molding (μIM) is a viable method for producing BCS with precise geometries and surface finishes. Yet, the inherent complexities of BCS geometry and the poor melt flow index (MFI) of material present significant obstacles to successful μIM fabrication. In this study, poly-lactic acid (PLA), was modified with triethyl citrate (TEC), a bio-based plasticizer, to enhance its MFI and processability. A comprehensive characterization of the PLA-TEC formulations was conducted, encompassing mechanical strength, thermal stability, and rheological behavior, to optimize material performance for μIM. Subsequently, process parameters were optimised utilising response surface methodology to mitigate manufacturing defects such as underfilling and flash formation, ensuring the production of high-quality BCS. Through systematic material modification and process optimization, this study successfully demonstrates the feasibility of μIM for cost-effective, high-volume production of BCS with improved geometric fidelity.