Fabrication and Testing of Planar Stent Mesh Designs Using Carbon Infiltrated Carbon Nanotubes

Abstract

This paper explores and demonstrates the potential of using pyrolitic carbon as a material for coronary stents. Stents are commonly fabricated from metal, which has worse biocompatibilty than many polymers and ceramics. Pyrolitic carbon, a ceramic, is currently used in medical implant devices due to its preferrable biocompatibility properties. It can be created by growing carbon nanotubes, and then filling the space between with amorpheous carbon via chemical vapor deposition. We prepared multiple samples of two different stent-like flexible geometry designs out of carbon infiltrated carbon nanotubes. Tension loads were applied to expand the samples and we recorded the forces at brittle failure. These data were then used in conjunction with a nonlinear FEA model of the stent geometry to determine Youngs modulus and maximum fracture strain for each sample. Additionally, images were recorded of the samples before, during, and at failure. These images were used to measure an overall percent elongation for each sample. The highest fracture strain observed was 1.4% and Youngs modulus values confirmed the the material was the similar to that used in previous carbon infiltrated carbon nanotube work. The average percent elongation was 86% and reached as high as 145%. This exceeds a typical target of 66%.