Artificial Tribotactic Microscopic Walkers: Walking Based on Friction Gradients

Friction, the resistive force between two surfaces sliding past each other, is at the core of a wide diversity of locomotion schemes. While such schemes are well described for homogeneous environments, locomotion based on friction in inhomogeneous environments has not received much attention. Here w...

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Bibliographic Details
Main Authors: Steimel, Joshua P., Alexander-Katz, Alfredo, Aragones Gomez, Juan Luis
Other Authors: Massachusetts Institute of Technology. Department of Materials Science and Engineering
Format: Article
Language:English
Published: American Physical Society 2014
Online Access:http://hdl.handle.net/1721.1/91151
https://orcid.org/0000-0001-5554-1283
https://orcid.org/0000-0002-3771-2349
https://orcid.org/0000-0002-1724-0241
Description
Summary:Friction, the resistive force between two surfaces sliding past each other, is at the core of a wide diversity of locomotion schemes. While such schemes are well described for homogeneous environments, locomotion based on friction in inhomogeneous environments has not received much attention. Here we introduce and demonstrate the concept of tribotaxis, a motion that is guided by gradients in the friction coefficient. Our system is composed of microwalkers that undergo an effective frictional interaction with biological receptors on the substrate, which is regulated by the density of such receptors. When actuated stochastically, microwalkers migrate to regions of higher friction, much like a chemotactic cell migrates to regions of higher chemoattractant concentration. Simulations and theory based on biased random walks are in excellent agreement with experiments. We foresee important implications for tribotaxis in artificial and natural locomotion in biological environments.