Long M, Goldsmith H L, Tees D F, Zhu C
George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0405, USA.
Biophys J. 1999 Feb;76(2):1112-28. doi: 10.1016/S0006-3495(99)77276-0.
A model was constructed to describe previously published experiments of shear-induced formation and breakage of doublets of red cells and of latexes cross-linked by receptor-ligand bonds (. Biophys. J. 65:1318-1334; Tees and Goldsmith. 1996. Biophys. J. 71:1102-1114;. Biophys. J. 71:1115-1122). The model, based on McQuarrie's master equations (1963. J. Phys. Chem. 38:433-436), provides unifying treatments for three distinctive time periods in the experiments of particles in a Couette flow in which a doublet undergoes 1) formation upon two-body collision between singlets; 2) evolution of bonds at low shear rate; and 3) break-up at high shear rate. Neglecting the applied force at low shear rate, the probability of forming a doublet per collision as well as the evolution of probability distribution of bonds in a preformed doublet were solved analytically and found to be in quite good agreement with measurements. At high shear rate with significant force acting to accelerate bond dissociation, the predictions for break-up of doublets were obtained numerically and compared well with data in both individual and population studies. These comparisons enabled bond kinetic parameters for three types of particles cross-linked by two receptor-ligand systems to be calculated, which agreed well with those computed from Monte Carlo simulations. This work can be extended to analyze kinetics of receptor-ligand binding in cell aggregates, such as those of neutrophils and platelets in the circulation.
构建了一个模型来描述先前发表的关于红细胞和通过受体 - 配体键交联的乳胶颗粒的剪切诱导双联体形成和破裂的实验（《生物物理杂志》65:1318 - 1334；蒂斯和戈德史密斯，1996年，《生物物理杂志》71:1102 - 1114；《生物物理杂志》71:1115 - 1122）。该模型基于麦夸里的主方程（1963年，《物理化学杂志》38:433 - 436），为库埃特流中颗粒实验的三个不同时间段提供了统一的处理方法，在该实验中，双联体经历：1）单颗粒之间的双体碰撞形成双联体；2）低剪切速率下键的演化；3）高剪切速率下的破裂。在低剪切速率下忽略外加力，解析求解了每次碰撞形成双联体的概率以及预先形成的双联体中键的概率分布的演化，发现与测量结果相当吻合。在高剪切速率下，有显著力作用以加速键的解离，通过数值方法获得了双联体破裂的预测结果，并与个体和群体研究中的数据进行了很好的比较。这些比较使得能够计算通过两种受体 - 配体系统交联的三种类型颗粒的键动力学参数，其与从蒙特卡罗模拟计算得到的参数吻合良好。这项工作可以扩展到分析细胞聚集体中受体 - 配体结合的动力学，例如循环中的中性粒细胞和血小板的聚集体。
