Institute of Bioengineering of Catalonia (IBEC), Barcelona, Spain.
Acta Biomater. 2010 Feb;6(2):667-75. doi: 10.1016/j.actbio.2009.08.043. Epub 2009 Sep 4.
Bioactive polymers bearing sulfonate (styrene sodium sulfonate, NaSS) and carboxylate (methylacrylic acid, MA) groups were grafted onto Ti6Al4V alloy surfaces by a two-step procedure. The Ti alloy surfaces were first chemically oxidized in a piranha solution and then directly subjected to radical polymerization at 70 degrees C in the absence of oxygen. The grafted surfaces were characterized by X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS) and the toluidine blue colorimetric method. Toluidine blue results showed 1-5microgcm(-2) of polymer was grafted onto the oxidized Ti surfaces. Grafting resulted in a decrease in the XPS Ti and O signals from the underlying Ti substrate and a corresponding increase in the XPS C and S signals from the polymer layer. The ToF-SIMS intensities of the S(-) and SO(-) ions correlated linearly with the XPS atomic percent S concentrations and the ToF-SIMS intensity of the TiO(3)H(2)(-) ion correlated linearly with the XPS atomic per cent Ti concentration. Thus, the ToF-SIMS S(-), SO(-) and TiO(3)H(2)(-) intensities can be used to quantify the composition and amount of grafted polymer. ToF-SIMS also detected ions that were more characteristic of the polymer molecular structure (C(6)H(4)SO(3)(-) and C(8)H(7)SO(3)(-) from NaSS, C(4)H(5)O(2)(-) from MA), but the intensity of these peaks depended on the polymer thickness and composition. An in vitro cell culture test was carried out with human osteoblast-like cells to assess the influence of the grafted polymers on cell response. Cell adhesion after 30min of incubation showed significant differences between the grafted and ungrafted surfaces. The NaSS grafted surfaces showed the highest degree of cell adhesion while the MA-NaSS grafted surfaces showed the lowest degree of cell adhesion. After 4 weeks in vivo in rabbit femoral bones, bone was observed to be in direct contact with all implants. The percentage of mineralized tissue around the implants was similar for NaSS grafted and non-grafted implants (59% and 57%). The MA-NaSS grafted implant exhibited a lower amount of mineralized tissue (47%).
通过两步法将带有磺酸根（苯乙烯磺酸钠，NaSS）和羧酸盐（甲基丙烯酸，MA）基团的生物活性聚合物接枝到 Ti6Al4V 合金表面。Ti 合金表面首先在过一硫酸溶液中进行化学氧化，然后在无氧条件下于 70°C 直接进行自由基聚合。接枝表面用 X 射线光电子能谱（XPS）、飞行时间二次离子质谱（ToF-SIMS）和甲苯胺蓝比色法进行了表征。甲苯胺蓝结果表明，聚合物接枝到氧化 Ti 表面的量为 1-5μg/cm(-2)。接枝导致来自基底 Ti 衬底的 XPS Ti 和 O 信号减少，而来自聚合物层的 XPS C 和 S 信号相应增加。S(-)和 SO(-)离子的 ToF-SIMS 强度与 XPS 原子百分比 S 浓度呈线性相关，TiO(3)H(2)(-)离子的 ToF-SIMS 强度与 XPS 原子百分比 Ti 浓度呈线性相关。因此，ToF-SIMS 的 S(-)、SO(-)和 TiO(3)H(2)(-)强度可用于定量接枝聚合物的组成和数量。ToF-SIMS 还检测到更能反映聚合物分子结构的特征离子（来自 NaSS 的 C(6)H(4)SO(3)(-)和 C(8)H(7)SO(3)(-)，来自 MA 的 C(4)H(5)O(2)(-)），但这些峰的强度取决于聚合物的厚度和组成。用人成骨样细胞进行了体外细胞培养试验，以评估接枝聚合物对细胞反应的影响。孵育 30 分钟后的细胞粘附显示接枝和未接枝表面之间存在显著差异。NaSS 接枝表面表现出最高的细胞粘附程度，而 MA-NaSS 接枝表面表现出最低的细胞粘附程度。在兔股骨骨内体内 4 周后，观察到骨与所有植入物直接接触。植入物周围矿化组织的百分比在 NaSS 接枝和未接枝植入物之间相似（59%和 57%）。MA-NaSS 接枝植入物表现出较少的矿化组织（47%）。
