Programmable and adaptable navigation of a magnetic and photoactive colloid

Colloids that are able to navigate via predefined paths and adapt to complex environments hold great promises as miniaturized machines and model systems for active soft matter research. Here, we design an intelligent system that integrates dynamic magnetic field and light control with in-situ determination of particle position and velocity via Matlab-based image acquisition and analysis. We apply the system to realize programmable and feedback control over the motion of a magnetic and photoactive colloid. Specifically, we direct the active colloid into pentagram-like navigation, circular motion of various size, and spiral-like motion by changing the travelling direction, discretely or continuously, the self-propelled velocity, and a combination of the two, enabled by dynamic change of magnetic field, light intensity and both. Moreover, we demonstrate the ability of the system for on-the-fly self-correction to follow predefined path with high fidelity, and adaptability to complex surroundings with definable birdlike vision based on in-situ processing of information. We expect the programmability and adaptability of magnetic and photoactive colloids enabled by multiple handles, magnetic field and light, open up new opportunities for active soft matter research, including intelligent microrobotics, collective nonequilibrium dynamics and novel photonic fluids.