Persaud-Sharma Dharam, Munroe Norman, McGoron Anthony
Florida International University, Department of Biomedical Engineering, 10555 W. Flagler Street, Miami, FL 33199, USA.
Trends Biomater Artif Organs. 2012;26(2):74-85.
In this study, an Atomic Force Microscopy (AFM) roughness analysis was performed on non-commercial Nitinol alloys with Electropolished (EP) and Magneto-Electropolished (MEP) surface treatments and commercially available stents by measuring Root-Mean-Square (RMS), Average Roughness (Ra), and Surface Area (SA) values at various dimensional areas on the alloy surfaces, ranging from (800 × 800 nm) to (115 × 115μm), and (800 × 800 nm) to (40 × 40 μm) on the commercial stents. Results showed that NiTi-Ta 10 wt% with an EP surface treatment yielded the highest overall roughness, while the NiTi-Cu 10 wt% alloy had the lowest roughness when analyzed over (115 × 115 μm). Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) analysis revealed unique surface morphologies for surface treated alloys, as well as an aggregation of ternary elements Cr and Cu at grain boundaries in MEP and EP surface treated alloys, and non-surface treated alloys. Such surface micro-patterning on ternary Nitinol alloys could increase cellular adhesion and accelerate surface endothelialization of endovascular stents, thus reducing the likelihood of in-stent restenosis and provide insight into hemodynamic flow regimes and the corrosion behavior of an implantable device influenced from such surface micro-patterns.
在本研究中，通过测量非商业镍钛诺合金经电解抛光（EP）和磁电解抛光（MEP）表面处理后的均方根（RMS）、平均粗糙度（Ra）和表面积（SA）值，以及市售支架在合金表面不同尺寸区域（范围从800×800纳米至115×115微米）和市售支架在800×800纳米至40×40微米区域的原子力显微镜（AFM）粗糙度分析。结果表明，经EP表面处理的10 wt% NiTi-Ta合金总体粗糙度最高，而在对115×115微米区域进行分析时，10 wt% NiTi-Cu合金粗糙度最低。扫描电子显微镜（SEM）和能量色散光谱（EDS）分析揭示了表面处理合金独特的表面形态，以及在MEP和EP表面处理合金及未进行表面处理的合金中，三元元素Cr和Cu在晶界处的聚集。这种三元镍钛诺合金表面的微图案化可增加细胞粘附并加速血管内支架的表面内皮化，从而降低支架内再狭窄的可能性，并深入了解受此类表面微图案影响的植入装置的血流动力学状态和腐蚀行为。
