Kendall K, Roberts A D
Metallurgy and Materials, University of Birmingham, Birmingham B15 2TT, UK
MRPRA, Hertford, UK.
Philos Trans R Soc Lond B Biol Sci. 2015 Feb 5;370(1661):20140078. doi: 10.1098/rstb.2014.0078.
Adhesion molecules, often thought to be acting by a 'lock and key' mechanism, have been thought to control the adhesion of cells. While there is no doubt that a coating of adhesion molecules such as fibronectin on a surface affects cell adhesion, this paper aims to show that such surface contamination is only one factor in the equation. Starting from the baseline idea that van der Waals force is a ubiquitous attraction between all molecules, and thereby must contribute to cell adhesion, it is clear that effects from geometry, elasticity and surface molecules must all add on to the basic cell attractive force. These effects of geometry, elasticity and surface molecules are analysed. The adhesion force measured between macroscopic polymer spheres was found to be strongest when the surfaces were absolutely smooth and clean, with no projecting protruberances. Values of the measured surface energy were then about 35 mJ m(-2), as expected for van der Waals attractions between the non-polar molecules. Surface projections such as abrasion roughness or dust reduced the molecular adhesion substantially. Water cut the measured surface energy to 3.4 mJ m(-2). Surface active molecules lowered the adhesion still further to less than 0.3 mJ m(-2). These observations do not support the lock and key concept.
黏附分子通常被认为是通过“锁钥”机制发挥作用，一直以来被认为可控制细胞黏附。虽然毫无疑问，诸如纤连蛋白等黏附分子在表面形成的涂层会影响细胞黏附，但本文旨在表明，这种表面污染只是其中一个因素。从范德华力是所有分子间普遍存在的吸引力这一基本观点出发，因此它必定对细胞黏附有所贡献，很明显，几何形状、弹性和表面分子的影响都必须叠加到基本的细胞吸引力上。本文对几何形状、弹性和表面分子的这些影响进行了分析。研究发现，当宏观聚合物球体表面绝对光滑且清洁、没有突出的凸起时，它们之间测得的黏附力最强。此时测得的表面能值约为35 mJ m(-2)，这与非极性分子间范德华引力的预期值相符。诸如磨损粗糙度或灰尘等表面凸起会大幅降低分子黏附。水会将测得的表面能降低至3.4 mJ m(-2)。表面活性分子会使黏附力进一步降低至小于0.3 mJ m(-2)。这些观察结果并不支持锁钥概念。
