Department of Surgery, The Pennsylvania State University, College of Medicine, Biomedical Engineering Institute, Hershey, PA 17033, USA.
Acta Biomater. 2010 Jun;6(6):1938-47. doi: 10.1016/j.actbio.2009.11.031. Epub 2009 Dec 3.
Microphase separation is a central feature of segmented polyurethane biomaterials and contributes to the biological response to these materials. In this study we utilized atomic force microscopy (AFM) to study the dynamic restructuring of three polyurethanes having soft segment chemistries of interest in biomedical applications. For each of the materials we followed the changes in near surface mechanical properties during hydration, as well as fibrinogen activity and platelet adhesion on these surfaces. Both AFM phase imaging and force mode analysis demonstrated that these polyurethane biomaterials underwent reorientation and rearrangement resulting in a net enrichment of hard domains at the surface. Fibrinogen activity and platelet adhesion on the polyurethane surfaces were found to decrease with increasing hydration time. The findings suggest that water-induced enrichment of hydrophilic hard domains at the surface changes the local surface physical and chemical properties in a way that influences the conformation of fibrinogen, changing the availability of the platelet-binding sites in the protein. This work demonstrates that the hydrated polyurethane biomaterial interface is a complex and dynamic environment where the surface chemistry is changing, altering the activity of fibrinogen and affecting blood platelet adhesion.
微相分离是嵌段型聚氨酯生物材料的一个主要特征，对这些材料的生物响应有贡献。在这项研究中，我们利用原子力显微镜（AFM）研究了三种具有生物医学应用中感兴趣的软段化学的聚氨酯的动态重构。对于每种材料，我们都跟踪了在水合过程中近表面机械性能的变化，以及这些表面上纤维蛋白原的活性和血小板黏附。AFM 相成像和力模式分析都表明，这些聚氨酯生物材料经历了重排和重新排列，导致硬段在表面的净富集。发现纤维蛋白原在聚氨酯表面的活性和血小板黏附随水合时间的增加而降低。研究结果表明，水诱导的亲水性硬段在表面的富集改变了局部表面物理和化学性质，从而影响纤维蛋白原的构象，改变蛋白质中血小板结合位点的可用性。这项工作表明，水合聚氨酯生物材料界面是一个复杂和动态的环境，表面化学在不断变化，改变纤维蛋白原的活性并影响血小板黏附。
