Catalytic Self-Propelled Nano/Micromotors. I. Principles and Geometry Design

Synthetic micro/nanomotors are functionalized micro/nanoparticles with the ability ofself-propelling motion. Synthetic micro/nanomotors are the mimic of mobile organismslike bacteria in nature. Micro/nanomotors have different types such as fuel required micro/nanomotors and fuel-free ones and various applications. Fuel-free micro/nanomotors movethrough environmental changes like increasing in temperature by heating, magnetic andultrasonic fields, etc. Platinum-based micro/nanomotors are the most common types of micro/nanomotors. Hydrogen peroxide is the fuel utilized in platinum-based micro/nanomotors.The decomposition of hydrogen peroxide fuel on the platinum surface of synthetic micro/nanomotors, supplies the required energy for motion of motors. Platinum-based micro/nanomotors have different structures and geometrics include spherical, stomatocyte, rod,tubular, and shell that that creates various motion mechanisms and speeds. The motionspeed of micro/nanomotors has a wide range of amounts from one micrometer per secondto hundreds micrometers per second. In this review, platinum-based micro/nanomotors andtheir different types have been introduced. In addition, different mechanisms of motioninclude self-electrophoresis, self-diffusiophoresis and bubble-propulsion mechanismshave been discussed. Then, the comparison of velocities in different motion mechanisms,applications of micro-nanomotors and the challenge of using their platinum type in in vivoconditions were also mentioned.