Surface and electrochemical properties of anodized pure iron for bioresorbable stents

Date

2026-1

Author

Gümüşkaya, İlkim Tuana

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Bioresorbable stents have emerged as a promising solution to the long-term complications of permanent metallic stents, such as restenosis and chronic inflammation. Among bioresorbable metals, pure iron offers superior mechanical strength, yet its clinical translation is limited by insufficiently controlled degradation behavior. In this study, anodization was employed as a surface modification strategy to regulate the degradation behavior and cytocompatibility of pure iron by tailoring surface characteristics. Two representative surfaces at the lower and upper limits of the achievable nanotube diameter range, 32 ± 7 nm (NT30) and 75 ± 14 nm (NT75), were selected to investigate structure–property relationships. These surfaces exhibited oxide-layer thicknesses of 175 ± 21 nm and 397 ± 20 nm, respectively, with corresponding surface roughness values of 6.5 ± 0.2 nm and 13.2 ± 1.1 nm. While grazing incidence X-ray diffraction (GIXRD) and vibrational spectroscopy analyses indicated the lack of long-range crystalline order in the anodic layer, X-ray photoelectron spectroscopy (XPS) results demonstrated that the surface is chemically composed of α-Fe2O3, α-FeOOH, and FeF3. Electrochemical analyses in 1 × simulated body fluid (SBF) at 37 °C revealed that NT30 showed the lowest corrosion rate (0.10 mm/y) and the most stable charge transfer resistance during time-dependent impedance monitoring. In vitro assays using extracts demonstrated that anodized samples supported endothelial cell proliferation for up to 5 days. Overall, anodized nanotubular oxide layers enable effective control of surface properties, degradation behavior, and cytocompatibility of pure iron for bioresorbable stent applications.

Subject Keywords

Pure iron, Anodization, Bioresorbable, Surface topography, Electrochemical degradation

URI

https://hdl.handle.net/11511/118732

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Graduate School of Natural and Applied Sciences, Thesis