Self-propelled predator-prey of swarming Janus micromotors

It is a long-standing challenge to accomplish bionic microrobot that acts in a similar way of white blood cell, chasing bacteria in complex environment. Without an effective external control field, most swarming microrobots systems are usually unable to perform directional movement and redirect their motion to capture the target. Here we report the predatory-prey dynamics of self-propelled clusters of Janus micromotors. The active cluster generates an oxygen bubbles cloud around itself by decomposing H₂O₂, which levitated it above the substrate, enhancing its mobility in solution to wander around to devour other clusters. The fast decomposition of H₂O₂ also induced a tubular low-concentration zone that bridges two clusters far separated from each other, resulting in a diffusio-osmotic pressure that drives the two clusters to meet. This predatory-prey phenomena mimic white blood cells chasing bacteria and swarming flocks in nature, shedding light on emergent collective intelligence in biology.