Adhesive force of a single gecko foot-hair
Adhesive force of a single gecko foot-hair
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DOI：
10.1038/35015073
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发表时间：
2000-06-08
期刊：
影响因子：
64.8
通讯作者：
Full, RJ
中科院分区：
文献类型：
--
作者：
Autumn, K;Liang, YA;Full, RJ
壁虎在光滑的垂直表面上快速攀爬的能力是非常特殊的（1-3）。显微镜显示壁虎的脚有近五十万角质毛或刚毛。每根30-130 μ m长的刚毛只有人类头发直径的十分之一，包含数百个突起，终止于0.2-0.5 μ m的刮刀状结构（2，4）。经过近一个世纪的解剖描述（2，4 -6），在这里我们报告了通过使用二维微机电系统力传感器（7）和作为测力计的电线首次直接测量单个刚毛力。测量结果显示，刚毛的粘附效果是整个动物最大估计值的10倍。附着力值支持这样的假设，即单个刚毛通过货车范德华力（8，9）起作用。壁虎脚趾伸直和脱皮的特殊行为使我们发现了刚毛的两个功能，这两个功能增强了它们的效力。一个独特的宏观取向和预加载的刚毛增加附着力600倍以上的摩擦测量的材料。适当定向的刚毛减少了剥离脚趾所需的力量，简单地脱离与底层的临界角以上。
Geckos are exceptional in their ability to climb rapidly up smooth vertical surfaces(1-3). Microscopy has shown that a gecko's foot has nearly five hundred thousand keratinous hairs or setae. Each 30-130 mu m long seta is only one-tenth the diameter of a human hair and contains hundreds of projections terminating in 0.2-0.5 mu m spatula-shaped structures(2,4). After nearly a century of anatomical description(2,4-6), here we report the first direct measurements of single setal force by using a two-dimensional micro-electromechanical systems force sensor(7) and a wire as a force gauge. Measurements revealed that a seta is ten times more effective at adhesion than predicted from maximal estimates on whole animals. Adhesive force values support the hypothesis that individual seta operate by van der Waals forces(8,9). The gecko's peculiar behaviour of toe uncurling and peeling(2) led us to discover two aspects of setal function which increase their effectiveness. A unique macroscopic orientation and preloading of the seta increased attachment force 600-fold above that of frictional measurements of the material. Suitably orientated setae reduced the forces necessary to peel the toe by simply detaching above a critical angle with the substratum.