ZnO-based micromotors fueled by CO2: the first example of self-reorientation-induced biomimetic chemotaxis

Abstract

Synthetic chemotactic micro/nanomotors are envisioned to actively ‘seek out’ targets by following specific chemicals, but they are mainly powered by bioincompatible fuels and only show pseudochemotaxis (or advanced chemokinesis) due to their weak self-reorientation capabilities. Here we demonstrate that synthetic ZnO-based Janus micromotors can be powered by an alternative biocompatible fuel of CO2, and further provide the first example of self-reorientation-induced biomimetic chemotaxis using them. The ZnO-based micromotors are highly sensitive to the dissolved CO2 in water, which enables the corrosion of ZnO to continuously occur by providing H+ through hydration. Thus, they can autonomously move even in the water exposed to air based on self-diffusiophoresis. Furthermore, they can sense local CO2 gradient and perform positive chemotaxis by self-reorientations under the electroosmotic viscous torque. Our discovery opens a gate to develop intelligent micro/nanomotors powered by and sensitive to biocompatible atmospheric or endogenous gaseous chemicals for biomedical and environmental applications.

Torque‐Driven Orientation Motion of Chemotactic Colloidal Motors

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Phototactic micromotor assemblies in dynamic line formations for wide-range micromanipulations

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A Robot Platform for Highly Efficient Pollutant Purification

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