Peattie Anne M, Majidi Carmel, Corder Andrew, Full Robert J
Department of Integrative Biology, University of California Berkeley, Berkeley, CA 94720-3140, USA.
J R Soc Interface. 2007 Dec 22;4(17):1071-6. doi: 10.1098/rsif.2007.0226.
Typical bulk adhesives are characterized by soft, tacky materials with elastic moduli well below 1MPa. Geckos possess subdigital adhesives composed mostly of beta-keratin, a relatively stiff material. Biological adhesives like those of geckos have inspired empirical and modelling research which predicts that even stiff materials can be effective adhesives if they take on a fibrillar form. The molecular structure of beta-keratin is highly conserved across birds and reptiles, suggesting that material properties of gecko setae should be similar to that of beta-keratin previously measured in birds, but this has yet to be established. We used a resonance technique to measure elastic bending modulus in two species of gecko from disparate habitats. We found no significant difference in elastic modulus between Gekko gecko (1.6 GPa +/- 0.15s.e.; n=24 setae) and Ptyodactylus hasselquistii (1.4 GPa +/- 0.15s.e.; n=24 setae). If the elastic modulus of setal keratin is conserved across species, it would suggest a design constraint that must be compensated for structurally, and possibly explain the remarkable variation in gecko adhesive morphology.
典型的块状粘合剂的特点是材料柔软、发粘，其弹性模量远低于1兆帕。壁虎拥有主要由β -角蛋白组成的指下粘合剂，β -角蛋白是一种相对坚硬的材料。像壁虎的生物粘合剂激发了实证研究和模型研究，这些研究预测，即使是坚硬的材料，如果呈现出纤维状形式，也可以成为有效的粘合剂。β -角蛋白的分子结构在鸟类和爬行动物中高度保守，这表明壁虎刚毛的材料特性应该与之前在鸟类中测量的β -角蛋白相似，但这一点尚未得到证实。我们使用共振技术测量了来自不同栖息地的两种壁虎的弹性弯曲模量。我们发现蛤蚧（弹性模量为1.6吉帕±0.15标准误；24根刚毛）和哈氏半叶趾虎（弹性模量为1.4吉帕±0.15标准误；24根刚毛）之间的弹性模量没有显著差异。如果刚毛角蛋白的弹性模量在物种间是保守的，这将表明存在一种设计限制，必须在结构上加以补偿，并且可能解释壁虎粘合剂形态的显著差异。
