A microcantilever device to assess the effect of force on the lifetime of selectin-carbohydrate bonds.
A microcantilever device to assess the effect of force on the lifetime of selectin-carbohydrate bonds.
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DOI：
10.1016/s0006-3495(01)76047-x
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发表时间：
2001-02
影响因子：
3.4
通讯作者：
D. Tees;Richard E. Waugh;Daniel A. Hammer
中科院分区：
文献类型：
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作者：
D. Tees;Richard E. Waugh;Daniel A. Hammer
微悬臂技术被用来向参与白细胞在血管壁上滚动的受体配体分子施加力。E-选择素被吸附在直径为3-μm、长4 mm的玻璃纤维上，选择素配体sialyl-lewisX偶联到乳胶微球上。在结合之后，使用计算机化的加载方案将微球和结合的纤维缩回，该加载方案将流体动力和纤维上的胡克力相结合，以产生一定范围的力加载速率(力/时间)、Rf。根据失效时的力分布，确定平均力，并将其绘制为lnrf的函数。曲线图的斜率和截距产生了无应力反向反应速率Kro，以及描述反向反应速率与力的关系的参数Ro。配基被滴定，因此∼30%的测试中发生了粘连，这意味着>；80%的粘合事件涉及单键。蒙特卡罗模拟表明，这种多重键合水平对参数估计的影响很小。在2 0 0-1 0 0 0和1 0 0 0-5 0 0 0pN S−1的范围内，估计的上载率分别为ARERO=0.048和0.0 16 nm，KRO=0.72和2.2s−1。莱文伯格-马夸特对所有rfgivesro=0.034 nm和kro=0.82s−1的值进行了拟合。这些参数的值都在胶粘剂动力学模拟所建议的轧制所需的范围内。
A microcantilever technique was used to apply force to receptor-ligand molecules involved in leukocyte rolling on blood vessel walls. E-selectin was adsorbed onto 3-μm-diameter, 4-mm-long glass fibers, and the selectin ligand, sialyl Lewisx, was coupled to latex microspheres. After binding, the microsphere and bound fiber were retracted using a computerized loading protocol that combines hydrodynamic and Hookean forces on the fiber to produce a range of force loading rates (force/time),rf. From the distribution of forces at failure, the average force was determined and plotted as a function of lnrf. The slope and intercept of the plot yield the unstressed reverse reaction rate,kro, and a parameter that describes the force dependence of reverse reaction rates,ro. The ligand was titrated so adhesion occurred in ∼30% of tests, implying that >80% of adhesive events involve single bonds. Monte Carlo simulations show that this level of multiple bonding has little effect on parameter estimation. The estimates arero=0.048 and 0.016nm andkro=0.72 and 2.2s−1for loading rates in the ranges 200–1000 and 1000–5000 pN s−1, respectively. Levenberg-Marquardt fitting across all values ofrfgivesro=0.034nm andkro=0.82s−1. The values of these parameters are in the range required for rolling, as suggested by adhesive dynamics simulations.