Gecko Adhesion as a Model System for Integrative Biology, Interdisciplinary Science, and Bioinspired Engineering: Video 2

A video from the 2014 review by Kellar Autumn, Peter Niewiarowski, and Jonathan B. Puthoff, "Gecko Adhesion as a Model System for Integrative Biology, Interdisciplinary Science, and Bioinspired Engineering," from the Annual Review of Ecology, Evolution, and Systematics.

Video and animation illustrating the mechanical requirements for attachment and detachment of a single isolated gecko seta (Autumn et al. 2000). The video shows a single seta glued to a minutien pin. The vertical bar at the left side is a 25-μm aluminum wire force gauge. Initial attempts to adhere a single isolated seta to a surface failed because we simply touched the tip of the seta into the surface and pulled away vertically. Instead, a slight preload force, followed by a micrometer-scale drag along the direction of curvature of the seta (i.e., toward the rear of the animal) switches the spatulae from their default unloaded state to the adhered state. The seta can now sustain a perpendicular pull because the adhesive van der Waals forces at the spatula tips resist detachment. Detachment occurs when the angle between the setal shaft and the surface exceeds 30°. This experiment illustrates the mechanical program for attachment and detachment required for controllable adhesion in gecko setae.