Adaptive Cu2O micromotors with pH-responsive phototaxis reversal

• Cu 2 O micromotors showed phototaxis reversal behavior by sensing the local pH change. • Cu 2 O micromotors with {1 1 0} and {1 1 1} facets exhibited superior motion efficiency. • Cu 2 O micromotor was capable of achieving precise macrophage transportation. Light-driven micro/nanomotors have made enormous progress in various practical applications owing to their excellent controllability and programmability. However, it is still far from real intellectualization. Herein we demonstrate the successful fabrication of hollow cuprous oxide (Cu 2 O) micromotors with autonomous phototaxis reversal behavior by in-situ sensing the local pH change of surrounding environment without altering the lighting direction. The fabricated motors exhibit excellent and controllable propulsion under low-strength visible light illumination (1100 LUX) due to faster charge separation between different facets of the crosslinked polyhedral Cu 2 O microstructures. Intriguingly, our Cu 2 O micromotors are possible to respond smartly to the local pH gradient and reverse from negative to positive phototaxis, therefore the motors are capable of evacuating automatically after mission. We envision that such adaptive micromotor with great intellectualization via responding autonomously to the local stimuli shows great promise in various applications especially biomedical scenarios.