Tozeren A
Biomedical Engineering Program, Catholic University of America, Washington, DC 20064.
J Biomech Eng. 1990 Aug;112(3):311-8. doi: 10.1115/1.2891189.
Cell-cell adhesion plays a fundamental role in tissue and organ development, cell mediated immunity and blood flow. In the present study a micro-mechanical model of specific adhesion is presented. Analytical expressions are derived for the adhesive energy density (gamma) at zero speed of peeling for the cases of immobile (trapped) as well as laterally mobile bonds. It is shown that gamma increases in both cases with the increasing density of bonds and with the binding of affinity of unstressed bonds. In the case of laterally mobile bonds gamma also increases with the extent of peeling. The analytical results are shown to be valid whether or not one takes into account of the bending stiffness of adhering membranes. It is also shown that gamma does not depend on the functional form of bond elasticity. The effect of the speed of peeling on the number density distribution of attached bonds is considered next. Numerical solutions for the energy required to separate conjugated cell pairs are presented. The theoretical predictions are then used to analyze experimental data on red cell aggregation and adhesion between a cytotoxic-T cell and its target cell. The results show that the binding affinity of unstressed bonds and their number density before conjugation can be obtained from data on slow peeling of cell-pairs. The information on the diffusivity of bonds, their stiffness and their rates of attachment and detachment are more difficult to obtain, requiring a set of experiments with increasing rates of separation (conjugation) of cell-pairs.
细胞间黏附在组织和器官发育、细胞介导的免疫以及血流中起着至关重要的作用。在本研究中，提出了一种特异性黏附的微观力学模型。针对固定（捕获）键以及横向移动键的情况，推导了零剥离速度下黏附能密度（γ）的解析表达式。结果表明，在这两种情况下，γ均随着键密度的增加以及未受力键亲和力的结合而增加。对于横向移动键的情况，γ还随着剥离程度的增加而增加。无论是否考虑黏附膜的弯曲刚度，解析结果均有效。还表明γ不依赖于键弹性的函数形式。接下来考虑剥离速度对附着键数密度分布的影响。给出了分离共轭细胞对所需能量的数值解。然后利用理论预测来分析关于红细胞聚集以及细胞毒性T细胞与其靶细胞之间黏附的实验数据。结果表明，未受力键的结合亲和力及其共轭前的数密度可从细胞对缓慢剥离的数据中获得。关于键的扩散率、刚度以及它们的附着和脱离速率的信息则更难获得，需要进行一系列细胞对分离（共轭）速率不断增加的实验。
