Self-navigating liquid crystalline microdroplets propelled by bacteria

Abstract

The unique attributes of active materials have enabled significant advancements across diverse sectors. Despite their potential, conventional non-electronic active materials still face substantial challenges, such as poor controllability, limited functionality, and complex fabrication processes. To address these limitations, we herein propose a versatile and robust strategy to realize a multifunctional liquid crystal (LC) droplet system by integrating it with motile bacteria. In this study, we demonstrate that a LC droplet in a preradial configuration serves as a sophisticated template for the anisometric bacterial binding on the droplet surface, which triggers the directional motion of the droplet. The propulsion of LC droplet can be finely tuned through the phase transition or molecular reorientation of LCs. Such mechanical outputs are coupled with the displacement of bacteria upon exposure to various stimuli, allowing for high-level command over the active transport. In addition, we show that the chemotactic dynamics of bacteria promote the autonomous transport of LC droplet toward designated targets, leveraging the bacteria’s innate sensing and navigational capabilities.