申请人前期研究发现，天然心瓣内皮细胞层表面存在微纳复合结构，且这些微纳复合结构所形成的沟槽方向与血流方向平行。申请人推测，天然心瓣的良好血流动力学特性可能与这些微纳复合结构有关：它们可使瓣膜表面的层流边界层免受破坏、抑制涡旋/湍流的产生，从而具有抑制血小板激活和抑制溶血的功能。为此，本项目设计了4个方面的研究内容来验证这一科学推测（hypothesis）：1）天然心瓣内皮细胞表面微纳结构的表征与建模；2）仿天然心瓣微纳结构表面的制备；3) 用PIV（粒子图像测速法）和计算机数值模拟的方法对比研究不同微结构表面对血流流场的影响；4)对比研究不同微结构表面对血小板激活以及溶血的影响。如果上述推测能够得到证实，我们便可以从在人工心瓣表面用物理的方法制备类似的微纳结构着手，来改善机械心瓣的血流动力学性能，这将是一个全新的研究思路。

The preliminary study by the applicant found that the endothelial surface of the natural heart valve had a micro-nano hierarchical structure that formed grooves, of which the direction was parallel to the direction of blood flow. The applicant hypothesizes that the excellent hemodynamic performance of the natural heart valve might be attributed to this micro-nano structure: It could prevent the laminar boundary layer on the valve surface from destruction, inhibiting vortex/turbulence formation, in turn suppressing platelet activation and hemolysis. In order to verify this hypothesis, the applicant designed 4 studies: 1) Characterization and modeling of the micro-nano structure of the natural heart valve endothelial surface; 2) Preparation of the surface with micro-nano structure mimicking the surface structure of the natural heart valve; 3) Comparative study on the hemodynamic performances of the surfaces with different micro-nano structures by using particle image velocimetry (PIV) and computational fluid dynamics; 4) Numerical and experimental studies on the surfaces with different micro-nano structures in terms of platelet activation and hemolysis. If the aforementioned hypothesis is verified to be true, we may pioneer new ways to design mechanical heart valves to improve their hemodynamic performance by mimicking the surface micro-nano hierarchical structure of the natural heart valve.