Authors: A. Sen
Affilation: Pennsylvania State University, United States
Pages: 270 - 272
Keywords: nanoparticles, electrokinetics, motion, electrophoresis, electroosmosis, microfluidics
Nanoscale moving systems are currently the subject of intense interest due in part to their potential applications in nanomachinery, nanoscale assembly, robotics, tribology, fluidics, and chemical/biochemical sensing. Most of the research in this area has focused on using biological motor proteins in artificial systems, or using “molecular motors” such as rotaxanes that are powered externally. We have shown that one can build nanomotors “from scratch” that mimic biological motors by using catalytic reactions to create forces based on chemical gradients. These motors are autonomous in that they do not require external electric, magnetic, or optical fields as energy sources. Instead, the input energy is supplied locally and chemically. By appropriate design, the chemical gradients can be translated into anisotropic body and/or surface forces. Depending on the shape of the object and the placement of the catalyst, different kinds of motion can be achieved. The resulting nanomotors can, in principle, be tethered or coupled to other objects to act as the “engines” of nanoscale assemblies. Additionally, an object that moves by generating a continuous surface force in a fluid can, in principle, be used to pump the fluid by the same catalytic mechanism. Thus, by immobilizing these nanomotors, we have developed micro/nanofluidic pumps that transduce energy catalytically.