Predicting human blood viscosity in silico
Predicting human blood viscosity in silico
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DOI：
10.1073/pnas.1101210108
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发表时间：
2011-07-19
影响因子：
11.1
通讯作者：
Karniadakis, George E.
中科院分区：
文献类型：
--
作者：
Fedosov, Dmitry A.;Pan, Wenxiao;Karniadakis, George E.
血液粘度长期以来一直被用作理解和治疗疾病的指标，现代粘度计的出现使其测量具有不断改进的临床便利性。然而，这些进展还没有与理论发展相匹配，这些理论发展可以产生对血液微观流变学及其与相关生物分子（例如，纤维蛋白原）。使用粗粒度的分子动力学和两种不同的红细胞模型，我们准确地预测血液粘度对剪切速率和红细胞压积的依赖性。我们明确表示细胞间的相互作用，并确定可逆的rouleaux结构的类型和大小，在低剪切速率下产生巨大的血液粘度增加。我们还提出了第一个定量估计红细胞之间的粘附力的大小。此外，我们的模拟支持的假设，以前推导出的实验，屈服应力作为细胞聚集的指标。分析了这种非牛顿行为，并将其与单个红细胞的悬浮液的微观结构、变形和动力学相关。最复杂的细胞动力学发生在中间剪切速率制度，其中个别细胞经历严重的变形和短暂的折叠构象。这些细胞模型的通用性与单细胞测量一起指向血液粘度异常的未来预测以及与各种疾病相关的相应微观结构（例如，疟疾、艾滋病和糖尿病）。该模型可以很容易地调整更广泛的一类复杂流体，包括胶囊和囊泡悬浮液的属性。
The viscosity of blood has long been used as an indicator in the understanding and treatment of disease, and the advent of modern viscometers allows its measurement with ever-improving clinical convenience. However, these advances have not been matched by theoretical developments that can yield a quantitative understanding of blood's microrheology and its possible connection to relevant biomolecules (e.g., fibrinogen). Using coarse-grained molecular dynamics and two different red blood cell models, we accurately predict the dependence of blood viscosity on shear rate and hematocrit. We explicitly represent cell-cell interactions and identify the types and sizes of reversible rouleaux structures that yield a tremendous increase of blood viscosity at low shear rates. We also present the first quantitative estimates of the magnitude of adhesive forces between red cells. In addition, our simulations support the hypothesis, previously deduced from experiments, of yield stress as an indicator of cell aggregation. This non-Newtonian behavior is analyzed and related to the suspension's microstructure, deformation, and dynamics of single red blood cells. The most complex cell dynamics occurs in the intermediate shear rate regime, where individual cells experience severe deformation and transient folded conformations. The generality of these cell models together with single-cell measurements points to the future prediction of blood-viscosity anomalies and the corresponding microstructures associated with various diseases (e.g., malaria, AIDS, and diabetes mellitus). The models can easily be adapted to tune the properties of a much wider class of complex fluids including capsule and vesicle suspensions.