School of Biomedical Engineering, McMaster University, 1280 Main Street West, Hamilton, ON, Canada L8S 4K1.
Acta Biomater. 2010 Aug;6(8):2911-9. doi: 10.1016/j.actbio.2010.02.043. Epub 2010 Mar 1.
Gold was used as a substrate for immobilization of an antithrombin-heparin (ATH) covalent complex to investigate ATH as a surface modifier to prevent blood coagulation. Three different surface modification methods were used to attach ATH to gold: (i) direct chemisorption; (ii) using dithiobis(succinimidyl propionate) (DSP) as a linker molecule and (iii) using polyethylene oxide (PEO) as a linker/spacer. The ATH-modified surfaces were compared to analogous heparinized surfaces. Water contact angles and X-ray photoelectron spectroscopy confirmed the modifications and provided data on surface properties and possible orientation. Ellipsometry measurements showed that surface coverage of DSP and PEO was high. ATH and heparin densities were quantified using radioiodination and quartz crystal microbalance, respectively. The surface density of ATH was greatest on the DSP surface (0.17 microg cm(-2)) and lowest on the PEO (0.05 microg cm(-2)). The low uptake on the PEO surface was likely due to the protein resistance of the PEO component. Using radioiodinated antithrombin (AT), it was shown that ATH-immobilized surfaces bound significantly greater amounts from both buffer and plasma than the analogous heparinized surfaces. Immunoblot analysis of proteins adsorbed from plasma demonstrated that surfaces chemisorbed with PEO, whether or not subsequently modified with ATH, inhibited non-specific adsorption. The immunoblot response for AT was stronger on the DSP-ATH than on the heparin surfaces, thus confirming the results from radiolabelling. The ATH surfaces again showed higher selectivity for AT binding than analogous heparin-modified surfaces, indicating the enhanced anticoagulant potential of ATH for biomaterial surface modification.
金被用作固定抗凝血酶-肝素（ATH）共价复合物的基底，以研究 ATH 作为防止血液凝固的表面修饰剂。使用三种不同的表面修饰方法将 ATH 附着到金上：（i）直接化学吸附；（ii）使用二硫代双（琥珀酰亚胺基丙酸酯）（DSP）作为连接分子；（iii）使用聚氧化乙烯（PEO）作为连接体/间隔物。ATH 修饰表面与类似肝素化表面进行了比较。水接触角和 X 射线光电子能谱证实了修饰，并提供了表面性质和可能的取向的数据。椭圆测量表明 DSP 和 PEO 的表面覆盖率很高。使用放射性碘标记和石英晶体微量天平分别定量了 ATH 和肝素的密度。ATH 的表面密度在 DSP 表面上最高（0.17 μg cm(-2)），在 PEO 表面上最低（0.05 μg cm(-2)）。PEO 表面上的低摄取可能是由于 PEO 成分的蛋白质抗性。使用放射性碘标记的抗凝血酶（AT），表明 ATH 固定化表面从缓冲液和血浆中结合的量明显大于类似的肝素化表面。从血浆中吸附的蛋白质的免疫印迹分析表明，无论是否随后用 ATH 修饰，PEO 化学吸附的表面都抑制了非特异性吸附。在 DSP-ATH 上的 AT 免疫印迹反应比在肝素表面上更强，从而证实了放射性标记的结果。ATH 表面再次显示出比类似肝素修饰表面更高的 AT 结合选择性，表明 ATH 对生物材料表面修饰具有增强的抗凝潜力。
