Wu Yiduo, Zhou Zhengrong, Meyerhoff Mark E
Department of Chemistry, The University of Michigan, Ann Arbor, Michigan 48109-1055, USA.
J Biomed Mater Res A. 2007 Jun 15;81(4):956-63. doi: 10.1002/jbm.a.31105.
Nitric oxide (NO) is released by endothelial cells that line the inner walls of healthy blood vessels at fluxes ranging from 0.5 x 10(-10) to 4.0 x 10(-10) mol cm(-2) min(-1), and this continuous NO release contributes to the extraordinary thromboresistance of the intact endothelium. To improve the biocompatibility of blood-contacting devices, a biomimetic approach to release/generate NO at polymer/blood interfaces has been pursued recently (with NO donors or NO generating catalysts doped within polymeric coatings) and this concept has been shown to be effective in preventing platelet adhesion/activation via several in vivo animal studies. However, there are no reports to date describing any quantitative in vitro assay to evaluate the blood compatibilities of such NO release/generating polymers with controlled NO fluxes. Such a methodology is desired to provide a preliminary assessment of any new NO-releasing material, in terms of the effectiveness of given NO fluxes and NO donor amounts on platelet activity before the more complex and costly in vivo testing is carried out. In this article, we report the use of a lactate dehydrogenase assay to study in vitro platelet adhesion on such NO-releasing polymer surfaces with varying NO fluxes. Reduced platelet adhesion was found to correlate with increasing NO fluxes. The highest NO flux tested, 7.05 (+/-0.25) x 10(-10) mol cm(-2) min(-1), effectively reduced platelet adhesion to nearly 20% of its original level (from 14.0 (+/-2.1) x 10(5) cells cm(-2) to 2.96 (+/-0.18) x 10(5) cells cm(-2)) compared to the control polymer coating without NO release capability.
一氧化氮（NO）由健康血管内壁的内皮细胞释放，释放通量范围为0.5×10⁻¹⁰至4.0×10⁻¹⁰摩尔·厘米⁻²·分钟⁻¹，这种持续的NO释放有助于完整内皮具有非凡的抗血栓形成能力。为了提高与血液接触装置的生物相容性，最近人们采用了一种仿生方法，在聚合物/血液界面释放/生成NO（将NO供体或NO生成催化剂掺杂在聚合物涂层中），并且通过多项体内动物研究表明，这一概念在防止血小板粘附/激活方面是有效的。然而，迄今为止，尚无报告描述任何定量体外试验来评估此类具有可控NO通量的NO释放/生成聚合物的血液相容性。在进行更复杂且成本更高的体内测试之前，需要这样一种方法来根据给定的NO通量和NO供体用量对血小板活性的有效性，对任何新型NO释放材料进行初步评估。在本文中，我们报告了使用乳酸脱氢酶测定法来研究在具有不同NO通量的此类NO释放聚合物表面上的体外血小板粘附情况。发现血小板粘附减少与NO通量增加相关。与没有NO释放能力的对照聚合物涂层相比，测试的最高NO通量7.05（±0.25）×10⁻¹⁰摩尔·厘米⁻²·分钟⁻¹有效地将血小板粘附降低至其原始水平的近20%（从14.0（±2.1）×10⁵个细胞·厘米⁻²降至2.96（±0.18）×10⁵个细胞·厘米⁻²）。
