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

Fangzhi Mou; Qi Xie; Jianfeng Liu; Shengping Che; Lamya Bahmane; Ming You; Jianguo Guan

doi:10.1093/nsr/nwab066

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

Natl Sci Rev. 2021 Apr 20;8(11):nwab066. doi: 10.1093/nsr/nwab066. eCollection 2021 Nov.

Authors

Fangzhi Mou¹, Qi Xie¹, Jianfeng Liu¹, Shengping Che¹, Lamya Bahmane¹, Ming You¹, Jianguo Guan¹

Affiliation

¹ State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, International of Materials Science and Engineering, Wuhan University of Technology, Wuhan 430070, China.

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 the 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 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 water exposed to air based on self-diffusiophoresis. Furthermore, they can sense the local CO₂ gradient and perform positive chemotaxis by self-reorientations under the phoretic torque. Our discovery opens a gate to developing intelligent micro/nanomotors powered by, and sensitive to, biocompatible atmospheric or endogenous gaseous chemicals for biomedical and environmental applications.

Keywords: carbon dioxide; chemotaxis; micro/nanomotors; self-propulsion; zinc oxide.