School of Biomedical Engineering, Faculty of Engineering, The University of Sydney, Darlington, NSW, 2008, Australia.
Charles Perkins Centre, The University of Sydney, Camperdown, NSW, 2006, Australia.
Sci Rep. 2021 Mar 25;11(1):6875. doi: 10.1038/s41598-021-86310-2.
Disturbed blood flow has been increasingly recognized for its critical role in platelet aggregation and thrombosis. Microfluidics with hump shaped contractions have been developed to mimic microvascular stenosis and recapitulate the prothrombotic effect of flow disturbance. However the physical determinants of microfluidic hemodynamics are not completely defined. Here, we report a refined computational fluid dynamics (CFD) simulation approach to map the shear rate (γ) and wall shear stress (τ) distribution in the stenotic region at high accuracy. Using ultra-fine meshing with sensitivity verification, our CFD results show that the stenosis level (S) is dominant over the bulk shear rate (γ) and contraction angle (α) in determining γ and τ distribution at stenosis. In contrast, α plays a significant role in governing the shear rate gradient (γ) distribution while it exhibits subtle effects on the peak γ. To investigate the viscosity effect, we employ a Generalized Power-Law model to simulate blood flow as a non-Newtonian fluid, showing negligible difference in the γ distribution when compared with Newtonian simulation with water medium. Together, our refined CFD method represents a comprehensive approach to examine microfluidic hemodynamics in three dimensions and guide microfabrication designs. Combining this with hematological experiments promises to advance understandings of the rheological effect in thrombosis and platelet mechanobiology.
血流紊乱因其在血小板聚集和血栓形成中的关键作用而受到越来越多的关注。采用驼峰状收缩的微流控技术已被开发用于模拟微血管狭窄，并再现血流紊乱的促血栓形成效应。然而，微流控血液动力学的物理决定因素尚未完全定义。在这里，我们报告了一种改进的计算流体动力学 (CFD) 模拟方法，以高精度绘制狭窄区域内的剪切率 (γ) 和壁面剪切应力 (τ) 分布。通过超精细网格和敏感性验证，我们的 CFD 结果表明，在狭窄处，狭窄程度 (S) 比整体剪切率 (γ) 和收缩角 (α) 更能决定 γ 和 τ 的分布。相比之下，α 在控制剪切率梯度 (γ) 分布方面起着重要作用，而对峰值 γ 的影响则很细微。为了研究粘度效应，我们采用广义幂律模型将血流模拟为非牛顿流体，与水介质中的牛顿模拟相比，γ 分布几乎没有差异。总之，我们改进的 CFD 方法代表了一种全面的方法来研究三维微流控血液动力学，并指导微制造设计。将其与血液学实验相结合，有望加深对血栓形成和血小板机械生物学中流变学效应的理解。
