Tao Zhang,Yuguo Deng,Bo Zhou,Jiayu Liu,Yufeng Su,Mu Li,Weiwei Zhang
Swarming robotic systems, which stem from insect swarms in nature, exhibit a high level of environmental adaptability and enhanced tasking capabilities for targeted delivery and micromanipulation. Here, we present a strategy that reconfigures paramagnetic nanoparticles into microswarms energized by a sawtooth magnetic field. A rotary-stepping magnetic-chain mechanism is proposed to address the forming principle of disk-like swarms. Based on programming the sawtooth field, the microswarm can perform reversible transformations between a disk, an ellipse and a ribbon, as well as splitting and merging. In addition, the swarms can be steered in any direction with excellent maneuverability and a high level of pattern stability. Under accurate manipulation of a magnetic microswarm, multiple microparts with complicated shapes were successfully combined into a complete assembly. This reconfigurable swarming microrobot may shed light on the understanding of complex morphological transformations in living systems and provide future practical applications of microfabrication and micromanipulation.Keywords:microrobot;disk-like swarm;sawtooth magnetic field;microassembly
Fuel-free light-driven micromotors have attracted increasing attention since the advantages of reversible, noninvasive, and remote maneuver are on demand with excellent spatial and temporal resolution. However, they suffer from a challenging bottleneck of the rather modest motion speed, which hinders their applications, needing to overcome the water flow movement in environmental water. Herein, we demonstrate a near-infrared (NIR) light-steered, precise navigation-controlled micromotor based on a reduced graphene oxide aerogel microsphere (RGOAM), which possesses an isotropic structure and is easily prepared by a one-step electrospray approach other than conventional light-propelled micromotors with the Janus structure. Benefiting from the ultralight weight of the aerogel and lesser fluid resistance on the water surface, the RGOAM motors show a higher motion speed (up to 17.60 mm/s) than that in the published literature, letting it overcome counterflow. Taking advantage of the photothermal conversion capacity of the RGOAM under an asymmetric light field, it is capable of moving both on the water driven by the Marangoni effect and under the water via light-manipulated density change. The motion direction and speed on water as well as the “start/stop” state can be precisely steered by NIR light even in a complicated maze. Due to its strong adsorption and loading capacity, the RGOAM can be applied for active loading-transport-release of dyes on demand as well as micropart assembling and shaping. Our work provides a strategy to achieve high speed, precise navigation control, and functional extensibility simultaneously for micromotors, which may offer considerable promise for the broad biomedical and environmental applications.
危险品化学品经营许可证（带存储）