X-ray Driven Microswimmers

Abstract

Light-powered manipulation of small objects in fluids significantly affects fields as diverse as drug/cell delivery, microsurgery, environmental remediation, and self-assembly/nanofabrication. Although many clever techniques based on UV-visible-NIR light have been devised, new methods that can have sufficient penetrating power into biological bodies are still in great demand. Since discovered by Röntgen, X-rays has long been regarded as the most celebrated light-source for non-invasive, whole-body medical imaging because of its outstanding penetration. Here, we observed that X-rays can drive propulsive motion of a half-metal coated Janus microparticle in aqueous environment. Using a full-field transmission X-ray microscope (TXM) with synchrotron hard X-rays, we simultaneously triggered and visualized the propulsive motion at single-particle level in aqueous solution. Our real-time observation at nanoscale revealed that the motion follows bubble growth induced by radiolysis of water at the metal/water interface. This study opens a potential to operate micro/nanorobots under whole-body medical imaging. In this talk, we will present our results and discuss the prospects of our work for potential applications in medicine.