Institute of Materials Science and Engineering, National Central University, No, 300, Jhongda Road, Jhong-Li, Taoyuan, 32001, Taiwan.
Nanoscale Res Lett. 2013 Apr 2;8(1):150. doi: 10.1186/1556-276X-8-150.
This work reports on the diameter-sensitive biocompatibility of anodic TiO2 nanotubes with different nanotube diameters grown by a self-ordering process and subsequently treated with supercritical CO2 (ScCO2) fluid. We find that highly hydrophilic as-grown TiO2 nanotubes become hydrophobic after the ScCO2 treatment but can effectively recover their surface wettability under UV light irradiation as a result of photo-oxidation of C-H functional groups formed on the nanotube surface. It is demonstrated that human fibroblast cells show more obvious diameter-specific behavior on the ScCO2-treated TiO2 nanotubes than on the as-grown ones in the range of diameters of 15 to 100 nm. This result can be attributed to the removal of disordered Ti(OH)4 precipitates from the nanotube surface by the ScCO2 fluid, thus resulting in purer nanotube topography and stronger diameter dependence of cell activity. Furthermore, for the smallest diameter of 15 nm, ScCO2-treated TiO2 nanotubes reveal higher biocompatibility than the as-grown sample.
这项工作报道了通过自组装工艺生长的不同管径的阳极 TiO2 纳米管的直径敏感性生物相容性，这些纳米管随后用超临界 CO2（ScCO2）流体进行处理。我们发现，高亲水性的原始 TiO2 纳米管在 ScCO2 处理后变得疏水，但由于纳米管表面形成的 C-H 官能团的光氧化，可以在紫外光照射下有效恢复其表面润湿性。研究表明，在 15 至 100nm 的直径范围内，与原始生长的 TiO2 纳米管相比，人成纤维细胞在 ScCO2 处理的 TiO2 纳米管上表现出更明显的直径特异性行为。这一结果归因于 ScCO2 流体从纳米管表面去除无序的 Ti(OH)4 沉淀物，从而导致更纯净的纳米管形貌和更强的细胞活性与直径的相关性。此外，对于最小直径 15nm 的情况，ScCO2 处理的 TiO2 纳米管显示出比原始生长样品更高的生物相容性。
