Diatom Bionanotribology—Biological Surfaces in Relative Motion: Their Design, Friction, Adhesion, Lubrication and Wear

Abstract

Tribology is the branch of engineering that deals with the interaction of surfaces in relative motion (as in bearings or gears): their design, friction, adhesion, lubrication and wear. Continuous miniaturization of technological devices like hard disc drives and biosensors increases the necessity for the fundamental understanding of tribological phenomena at the micro- and nanoscale. Biological systems show optimized performance also at this scale. Examples for biological friction systems at different length scales include bacterial flagella, joints, articular cartilage and muscle connective tissues. Scanning probe microscopy opened the nanocosmos to engineers: not only is microscopy now possible on the atomic scale, but even manipulation of single atoms and molecules can be performed with unprecedented precision. As opposed to this top-down approach, biological systems excel in bottom-up nanotechnology. Our model system for bionanotribological investigations are diatoms, for they are small, highly reproductive, and since they are transparent, they are accessible with different kinds of optical microscopy methods. Furthermore, certain diatoms have proved to be rewarding samples for mechanical and topological in vivo investigations on the nanoscale. There are several diatom species that actively move (e.g. Bacillaria paxillifer forms colonies in which the single cells slide against each other) or which can, as cell colonies, be elongated by as much as a major fraction of their original length (e.g. Ellerbeckia arenaria colonies can be reversibly elongated by one third of their original length). Therefore, we assume that some sort of lubrication of interactive surfaces is present in these species. Current studies in diatom bionanotribology comprise techniques like atomic force microscopy, histochemical analysis, infrared spectrometry, molecular spectroscopy and confocal infrared microscopy.

Micromechanics in biogenic hydrated silica: Hinges and interlocking devices in diatoms

“…Diatoms are small, easy to cultivate, and because many of them are transparent, they are accessible to in vivo light microscopy techniques. Furthermore, some diatom species that stably adhere to a substratum are also accessible with atomic force microscopy techniques [11,12,[19][20][21][22][23][24]. In addition, atomic force spectroscopy can yield important information on micro-and nanomechanical properties such as adhesion, viscoelasticity, hardness, and so on.…”

Swarming: Flexible Roaming Plans

“…Interaction of surfaces in relative motion is influenced by their design, friction, adhesion, lubrication, and wear; the study of this interaction is a specialized branch of engineering called tribology, with bio-tribology being a large subfield (41,42). Examples of moving surfaces in biology range in scale from bacterial flagellar motors rotating in the membrane, to diatoms sliding past each other, to bone/cartilage joints.…”

Insight into tribological problems of green ship and corresponding research progresses

“…The study on bionics assumes that the structure of rib-like squama that covers the shark body effectively prevents the surface from being adhered by sea creatures, and especially, reduces the vibration owing to the fluid flowing at a high relative speed. After the process of abstraction, amplification, and simplification based on the real microstructure of the shark squama, the bionic shark skin made in laboratory can currently contribute to about 7% of drag reduction in a test subject [20][21][22]. Using the forming technology of biological replication, Han et al [23] designed a kind of bionic shark skin and claimed that this structure can improve the ratio of drag reduction up to 24.6%.…”