Geometric design of microfluidic chambers: platelet adhesion versus accumulation
Geometric design of microfluidic chambers: platelet adhesion versus accumulation
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DOI：
10.1007/s10544-013-9811-7
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发表时间：
2014-02-01
影响因子：
2.8
通讯作者：
Ku, David N.
中科院分区：
文献类型：
--
作者：
Casa, Lauren D. C.;Ku, David N.
富含血小板的动脉血栓形成取决于剪切速率和整合素与胶原表面或生长血栓的结合，这在机制上是不同的。一般来说，小的微流体测试切片可能有利于血小板表面粘附，而不测试动脉内血栓形成的主要模式，即血小板-血小板结合和积聚。在本报告中，使用圆形和矩形试验切片的分析方法估计血小板-血小板与血小板-表面相互作用的比率R和血小板-血小板相互作用的百分比P。结果表明，试验段的几何形状强烈影响R和P，在低纵横比通道或直径大于90 μ m的试验段高度主要由血小板-血小板相互作用（R > 10）。增加矩形试验段的纵横比会降低所需的高度。随着通道尺寸的增加，R线性增加，而P渐近地接近100%。血小板形状的分析表明，球形血小板的假设对R的影响较小，相比盘状血小板贴在测试部分的墙壁上。然而，平均血小板体积的增加导致R的大幅下降。尽管如此，人体血小板大小的典型分布的蒙特卡罗模拟显示，血小板大小的受试者内变化对R的净影响仅为10%。最后，血栓形成实验表明，当R > 10时，矩形微流控测试切片和圆形测试切片的血小板表面滞后时间和血小板-血小板聚集相似。研究结果表明，在研究细胞-细胞积累与细胞-表面粘附时，应仔细考虑微流体测试切片的大小。
Arterial, platelet-rich thrombosis depends on shear rates and integrin binding to either a collagen surface or to the growing thrombus, which are mechanistically different. In general, small microfluidic test sections may favor platelet-surface adhesion without testing for the primary mode of intra-arterial thrombosis, i.e. platelet-platelet bonding and accumulation. In the present report, the ratio of platelet-platelet to platelet-surface interactions, R, and the percentage of platelet-platelet interactions, P, are estimated using an analytical approach for circular and rectangular test sections. Results show that the test section geometry strongly affects both R and P, with test section height in low-aspect ratio channels or diameter greater than 90 mu m dominated by platelet-platelet interactions (R > 10). Increasing rectangular test section aspect ratio decreases the required height. R increases linearly while P approaches 100 % asymptotically with increasing channel dimension. Analysis of platelet shape shows that the assumption of spherical platelets has a small effect on R compared to discoid platelets adhering flat against test section wall. However, an increase in average platelet volume resulted in a large decrease in R. Nonetheless, Monte Carlo simulations of a typical distribution of human platelet sizes show intrasubject variation in platelet size has only a 10 % net effect on R. Finally, experiments of thrombus formation show that platelet-surface lag times and platelet-platelet accumulation are similar for rectangular microfluidic test sections and round test sections when R > 10. The findings show that the size of a microfluidic test section should be carefully considered in studies of cell-cell accumulation versus cell-surface adhesion.