Development and characterization of a coronary polylactic acid stent prototype generated by selective laser melting

Area of Science:

• Biomaterials Science
• Medical Device Manufacturing
• Cardiovascular Research

Background:

• In-stent restenosis and stent thrombosis remain significant risks following coronary interventions.
• Biodegradable stents offer a temporary scaffold that dissolves over time, potentially mitigating long-term complications.
• Additive manufacturing, specifically Selective Laser Melting (SLM), provides advanced capabilities for creating complex 3D structures.

Purpose of the Study:

• To adapt Selective Laser Melting (SLM) process parameters for biodegradable polymers, poly-L-lactide acid (PLLA) and PLLA-co-poly-ε-caprolactone (PCL).
• To generate and evaluate customized biodegradable coronary artery stent prototypes.
• To assess the biocompatibility and safety of SLM-processed biodegradable stent materials.

Main Methods:

• Selective Laser Melting (SLM) process parameters were optimized for PLLA and PCL powders.
• Biocompatibility was assessed using human coronary artery smooth muscle cells, umbilical vein endothelial cells, and endothelial progenitor cells.
• γ-sterilization was performed, and stent surfaces were post-processed via spray- and dip-coating.

Main Results:

• Successful generation of biodegradable coronary stent prototypes from PLLA and PCL using SLM.
• Demonstrated biocompatibility of both polymers through cell morphology, metabolic, and adhesive activity assessments.
• Confirmed the safety of SLM-processed parts after γ-sterilization and effective surface smoothening through coating techniques.

Conclusions:

• Biodegradable polymers combined with SLM technology enable the first-ever manufacturing of customized biodegradable coronary artery stent prototypes.
• SLM is a viable technique for developing biodegradable coronary stents from PLLA and PCL.
• These stents hold potential for future optimization, particularly for bifurcation applications.