On The Approach to Nanoscale Robots: Understanding the Relationship between Nanomotor's Architecture and Active Motion

Nanomotors with active motion have recently attracted wide attention. Researchers have developed a series of nanomotors with different architectures and propulsion mechanisms and have also explored the application prospects of nanomotors in many fields. Yet, the present nanomotors with simple component and motion behaviors are still far from the ultimate goal of nanoscale robots with controlled sophisticated motions. With this goal in mind, researchers are no longer satisfied with just making nanoparticles move actively, but looking forward to achieving precise control of the motion behavior of nanomotors. With the advance in nanofabrication techniques, tuning the nanomotors' motion by modulating the structure of nanoparticles has become a widely welcomed approach. This article reviews the self-propelling mechanisms and the various synthesis methods of nanomotors. It is also systematically summarized how the composition, surface properties, size, and morphology of nanoparticles affect their motion behavior. Some outstanding works are highlighted, the shortcomings, challenges, and opportunities in the field are also discussed. It is believed that a thorough review of the architecture-motion relationships of nanomotors is beneficial for the development of the field toward nanoscale robots.