Meeting Abstract
Adhesion, and in particular long-term reversible adhesion, to a wet or submerged surface is challenging. In the natural world, few organisms can adhere to underwater substrates and those that do generally use glue-like mechanisms or attach only to stationary objects. Remora fishes have evolved a unique adaptive ability – an adhesive disc formed from dorsal fin elements – that allows them to attach reversibly to actively deforming bodies of varying roughness and compliance that move at high speed. The adhesive disc is a hierarchical structure, in which the lamellae, spinules, fleshy outer lip, and cranial vessels all contribute to the generation of suction and friction for initial attachment and long-term hold. We found that remora body shape adds hydrodynamic advantages to adhesion and resistance to drag as well. The wall effect created by the flat disc approaching a host organism generates a suction pressure that helps to pull the remora to its host. Upon contact, the fleshy outer lip generates a viscoelastic seal as the lamellae rotate to produce a subambient pressure beneath the disc. Individual lamellar chamber pressures may be equalized by the anterior cardinal sinus. Lamellar contact with the host engages spinule interaction with the host surface, thereby generating frictional forces that oppose shear. Our continued assessment of these mechanisms and the material properties of these structures is leading towards a bioinspired adhesive device that will be useful in ecology, medicine, and defense.
