Bionic morphological design and interface-free fabrication of halfmoon microrobots with enhanced motion performance

Micro/nanorobots with the ability to explore the microworld have attracted extensive research interest for the promising biomedical application. However, the extremely low motion stability and efficiency by active self-propulsion and remote control at the sub-micron scale greatly limit its practical application. The morphological structure of micro/nanorobots with high kinetic stability and efficiency needs to be designed and prepared. Here, inspired by halfmoon betta fish, the halfmoon Janus microrobots (HJMRs) with stable directional motion performance at the sub-micron scale were developed. Through modeling analysis, the halfmoon morphology was proved a better anti-interference ability to the fluid and irregular Brownian motion than other morphologies. An interface-free Janus preparation method was developed for the production of halfmoon Janus nanoparticles and asymmetric loading of platinum to prepare HJMRs. Benefiting from the bionic rational morphological design, HJMR showed enhanced directional motion performance under chemical propulsion. HJMR also presented programmable motion control and transformable swarm control using magnetic field. HJMR was further utilized as active catalytic carriers to execute tumor-targeted propulsion and trigger the tumor-selective cascade reaction for active tumor therapeutics. The rational morphological design of microrobots with enhanced motion performance and the universal interface-free Janus preparation holds considerable promise for the large-scale production of active Janus microrobots and practical biomedical applications.