Micromotors are very small particles (measured in microns) that can move themselves.[1] The term is often used interchangeably with "nanomotor," despite the implicit size difference. These micromotors actually propel themselves in a specific direction autonomously when placed in a chemical solution. There are many different micromotor types operating under a host of mechanisms. Easily the most important examples are biological motors such as bacteria and any other self-propelled cells. Synthetically, researchers have exploited oxidation-reduction reactions to produce chemical gradients, local fluid flows, or streams of bubbles that then propel these micromotors through chemical media.[2] Different stimuli, both external (light,[3] magnetism[4]) and internal (fuel concentration, material composition,[5] particle asymmetry[6]) can be used to control the behavior of these micromotors.
Micromotors may have applications in medicine since they have been shown to be able to deliver materials to living cells within an organism. They also have been shown to be effective in degrading certain chemical and biological warfare agents.