Glucose-fueled Micromotors with Highly Efficient Visible Light Photocatalytic Propulsion.

Synthetic micro/nanomotors powered by the green energy and operated in completely biocompatible conditions are strongly desired for numerous practical applications. Glucose is one of the most attractive fuels for driven micro/nanomotors due to its outstanding biocompatible properties. However, currently, all of the glucose-fuelled micro/nanomotors based on enzyme-catalytic driven mechanisms and usually suffer from strict operated conditions and weak propulsions which greatly limit their applications. Here, we report the fastest glucose-fuelled cuprous oxide@N doped carbon nanotube (Cu2O@N-CNT) photocatalytic micromotor, which can be operated in fully green environment. We firstly use photocatalytic reactions instead of enzymatic reactions to decompose biocompatible glucose so as to generate sufficient energy for efficiently propelling micro/nanomotors, and such photocatalytic methods are extremely efficient, stable and easy operated compared to previously reported enzymatic ways. To the best of our knowledge, the Cu2O@N-CNT micromotors are the most powerful glucose-fuelled micromotors up to now, the speed can reach up to18.71 μm/s, which is comparable to conventional Pt-based catalytic Janus micromotors usually fuelled by toxic H2O2 fuels. In addition, such micromotors are the fastest photocatalytic micromotors which can be operated in fully green environments so far. The speeds of motors are almost 12 times fast than that of previous reported visible light-driven micromotors (around 1.61 μm/s) in pure water. Furthermore, the velocities of such motors can be efficiently regulated by multiple approaches, such as adjusting the N-CNTs contents within the micromotors, glucose concentrations or light intensities. Finally, the Cu2O@N-CNTmicromotors exhibit highly controllable negative phototaxis behavior (moving away from light source) due to their unique light-induced self-diffusiophoretic propulsion mechanism, thus, their directions can be precisely controlled by regulating the light sources positions. Such motors with outstanding propulsion in biological environments, and wireless, repeatable, light-modulated three dimensional motion control are extremely attractive for future practical applications.