Rheometrical and molecular dynamics simulation studies of incipient clot formation in fibrin-thrombin gels: An activation limited aggregation approach
Rheometrical and molecular dynamics simulation studies of incipient clot formation in fibrin-thrombin gels: An activation limited aggregation approach
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DOI：
10.1016/j.jnnfm.2011.04.016
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发表时间：
2011-09-01
影响因子：
3.1
通讯作者：
Williams, P. R.
中科院分区：
文献类型：
--
作者：
Curtis, D. J.;Brown, M. R.;Williams, P. R.
报道了对纤维蛋白-凝血酶凝胶中形成的初期凝块的流变学研究，其中凝胶点（GP）的特征在于在宽范围的凝血酶浓度下小振幅振荡剪切测量中损耗角正切的频率独立性。根据测量计算出的 GP 网络的分形维数 (D-f) 值与扩散限制簇-簇聚集 (DLCCA) 和反应限制簇-簇聚集 (RLCCA) 模拟中报告的值一致，但不同之处在于，根据本实验计算的 D-f 值随着凝胶形成时间的减少而逐渐增加。棒状颗粒系统的分子动力学模拟 (MDS) 旨在 (i) 测试以下假设：簇聚集模型中激活曲线的存在可以解释 D-f 的趋势，作为在纤维蛋白-凝血酶凝胶和全肝素化血液中实验观察到的凝胶形成时间的函数，而不需要包含纤维蛋白原特异性相互作用； (ii) 探索单体活化动力学对刚性棒状颗粒系统中形成的分形簇微观结构的影响。结果确定了随着凝胶形成时间减少而 D-f 增加的两种可能机制，这两种机制都是通过本文称为激活限制聚集（ALA）的过程改变聚类动力学演化的结果。这种基于 ALA 的 MDS 通过确认纤维蛋白-凝血酶凝胶和全肝素化血液中早期凝块形成的明显趋势，证实了实验结果。提出了一种涉及 GP 前子簇聚合的 ALA 机制。 (C) 2011 Elsevier B.V. 保留所有权利。
A rheometrical investigation of incipient clots formed in fibrin-thrombin gels is reported in which the Gel Point (GP) is characterised by frequency independence of the loss tangent in small amplitude oscillatory shear measurements over a wide range of thrombin concentration. Values of the fractal dimension (D-f) of the GP network calculated from measurements are consistent with those reported in simulations of diffusion limited cluster-cluster aggregation (DLCCA) and reaction limited cluster-cluster aggregation (RLCCA), but differ insofar as the values of D-f calculated from the present experiments increase progressively with a reduction in gel formation time. A molecular dynamics simulation (MDS) of systems of rodlike particles was designed to (i) test the hypothesis that the presence of an activation profile in a cluster aggregation model could account for the trend of D-f as a function of gel formation time observed experimentally in fibrin-thrombin gels and whole heparinised blood without recourse to the inclusion of fibrinogen-specific interactions; and (ii) to explore the effect of monomer activation kinetics on the microstructure of fractal clusters formed in systems of rigid rod-like particles. The results identify two possible mechanisms for the increase in D-f as the gel formation time decreases, both being a consequence of altering the evolution of the clustering dynamics by a process referred to herein as activation limited aggregation (ALA). This ALA-based MDS substantiates the experimental findings by confirming the trend evident in the formation of incipient clots in fibrin-thrombin gels and in whole heparinised blood. A mechanism for ALA involving the aggregation of pre-GP sub-clusters is proposed. (C) 2011 Elsevier B.V. All rights reserved.