Mechanical properties and biocompatibility of plasma-nitrided laser-cut 316L cardiovascular stents

• Published in: Journal of materials science. Materials in medicine Vol. 19; no. 5; pp. 2079 - 2086
• Main Authors: Arslan, Erdem, İğdil, Mustafa C., Yazici, Hilal, Tamerler, Candan, Bermek, Hakan, Trabzon, Levent
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01-05-2008; Springer Nature B.V
• Subjects: Alkaline Phosphatase - metabolism; Animals; Animals, Newborn; Biocompatible Materials - chemistry; Biomaterials; Biomedical Engineering and Bioengineering; Biomedical materials; Blood Vessel Prosthesis; Cardiovascular system; Ceramics; Chemistry and Materials Science; Composites; Glass; Lasers; Materials Science; Materials Testing; Microscopy, Electron, Scanning; Natural Materials; Nitric Oxide - metabolism; Osteoblasts - metabolism; Plasma; Polymer Sciences; Rats; Rats, Wistar; Regenerative Medicine/Tissue Engineering; Stainless Steel - chemistry; Stents; Stress, Mechanical; Studies; Surfaces and Interfaces; Temperature; Thin Films; Nitrided; Austenitic Stainless Steel; Nitric Oxide; Plasma Nitriding; Case Depth
• ISSN: 0957-4530; 1573-4838
• DOI: 10.1007/s10856-007-3302-4

The effect of surface modification of laser-cut 316L cardiovascular stents by low-T plasma nitriding was evaluated in terms of mechanical properties and biocompatibility of the stents. The plasma nitriding was performed at 400, 450 or 500 °C using various ratios of nitrogen–hydrogen gas mixtures. The flexibility and radial strength were measured in crimped and expanded state of the stents, respectively. The mechanical properties could be adjusted and improved by plasma nitriding conducted at temperatures lower than 450 °C and/or nitrogen content less than 10% in the treatment gas. An osteoblast cell culture model system was utilized to investigate the effect of plasma nitriding of the stents on the biological response towards the stents, using biological criteria such as cell viability, alkaline phosphatase and nitric oxide production. In terms of cell viability and alkaline phosphatase production, the plasma nitriding procedure did not appear to negatively affect the biocompatibility of the 316L steel stents. However, in terms of nitric oxide production that was slightly increased in the presence of the plasma-nitrided stents, an indirect improvement in the biocompatibility could possibly be expected.