Ward Joanna, Dunne Eimear, Bishop David, Boyd Adrian, Kenny Dermot, Meenan Brian J
Nanotechnology and Integrated Bioengineering Centre (NIBEC), Ulster University, Jordanstown BT37 0QB, UK.
Royal College of Surgeons in Ireland, 123 St. Stephen's Green, Dublin 2, Ireland.
Polymers (Basel). 2017 Dec 13;9(12):700. doi: 10.3390/polym9120700.
Human platelets play a vital role in haemostasis, pathological bleeding and thrombosis. The haemostatic mechanism is concerned with the control of bleeding from injured blood vessels, whereby platelets interact with the damaged inner vessel wall to form a clot (thrombus) at the site of injury. This adhesion of platelets and their subsequent aggregation is dependent on the presence of the blood protein von Willebrand Factor (vWF). It is proposed here that the entrapment of vWF on a substrate surface offers the opportunity to assess an individual's platelet function in a clinical diagnostic context. Spin coating from demixed solutions of polystyrene (PS) and poly(methyl methacrylate) (PMMA) onto glass slides has been shown previously to support platelet adhesion but the mechanism by which this interaction occurs, including the role of vWF, is not fully understood. In this work, we report a study of the interaction of platelets in whole blood with surfaces produced by spin coating from a solution of a weight/weight mixture of a 25% PS and 75% PMMA (25PS/75PMMA) in chloroform in the context of the properties required for their use as a Dynamic Platelet Function Assay (DPFA) substrate. Atomic Force Microscopy (AFM) indicates the presence of topographical features on the polymer demixed surfaces in the sub-micron to nanometer range. X-ray Photoelectron Spectroscopy (XPS) analysis confirms that the uppermost surface chemistry of the coatings is solely that of PMMA. The deliberate addition of various amounts of 50 μm diameter PS microspheres to the 25PS/75PMMA system has been shown to maintain the PMMA chemistry, but to significantly change the surface topography and to subsequently effect the scale of the resultant platelet interactions. By blocking specific platelet binding sites, it has been shown that their interaction with these surfaces is a consequence of the entrapment and build-up of vWF from the same whole blood sample.
人类血小板在止血、病理性出血和血栓形成过程中发挥着至关重要的作用。止血机制涉及对受损血管出血的控制，在此过程中，血小板与受损的血管内壁相互作用，在损伤部位形成凝块（血栓）。血小板的这种黏附及其随后的聚集依赖于血液蛋白血管性血友病因子（vWF）的存在。本文提出，将vWF捕获在底物表面为在临床诊断环境中评估个体的血小板功能提供了机会。先前已表明，从聚苯乙烯（PS）和聚甲基丙烯酸甲酯（PMMA）的混合溶液旋涂到载玻片上能够支持血小板黏附，但这种相互作用发生的机制，包括vWF的作用，尚未完全了解。在这项工作中，我们报告了一项关于全血中血小板与通过从氯仿中25% PS和75% PMMA（25PS/75PMMA）的重量/重量混合物溶液旋涂产生的表面相互作用的研究，该表面是作为动态血小板功能测定（DPFA）底物所需的特性。原子力显微镜（AFM）表明在聚合物相分离表面上存在亚微米到纳米范围内的形貌特征。X射线光电子能谱（XPS）分析证实涂层的最上层表面化学仅为PMMA。已表明在25PS/75PMMA体系中故意添加各种数量的直径为50μm的PS微球可保持PMMA化学性质，但会显著改变表面形貌，并随后影响所得血小板相互作用的规模。通过阻断特定的血小板结合位点，已表明它们与这些表面的相互作用是同一全血样本中vWF捕获和积累的结果。
