A dual-driven biomimetic microrobot based on optical and magnetic propulsion

The microrobot, which can address the fuel depletion and wire limitation, has exhibited great potential in the fields of lab-on-chip devices, sensing and monitoring devices, and some biomedical applications. In this paper, a dual-driven wireless microrobot, which can harvest and convert external optical and magnetic energy into the kinetic energy, is described. The dual-driven microrobot is fabricated by using a rapid 3D printing technology. Au and Ni nanoparticles are deposited on the surface of the microrobot, responsible for the optical and magnetic propulsion modes, respectively. The strong infrared light absorption of Au can induce a thermal convection and thus propel the movement of the microrobot. Similarly, the magnetic gradient field exerted on the Ni nanoparticles is applied to enable the magnetic manipulation of the microrobot. The experimental results demonstrate that the applied magnetic field and laser beam can provide efficient interventions on the ‘start/stop’ states, the speed and direction of the movement as well as the position of the microrobot in a remotely controlled manner. We can manipulate the microrobot with both fine microrange motion adjustment and wide range movement control that cannot be achieved by using a single propulsion mode. Dynamic switching of the light driven mode and the magnetic propulsion mode are also presented, which indicates that the microrobot can overcome the strong viscous force and display efficient motions in fluids under each propulsion mode. Such dual-driven propulsion method offers a broad scope for designing smart micro-vehicles that can reconfigure their operation mode according to their mission and surrounding environments.