Proteins inspire tiny motors
doi:10.1038/nindia.2010.87 Published online 30 June 2010
Researchers have devised a new model that may aid the design of microscopic motors. The model mimics the random movement of particles in a fluid by taking clues from biological molecules, paving the way for future nanoscale applications such as molecular pumps, transistors and even micrometre-sized factories that assemble motors for use in microscopic surgery.
The idea of a microscopic motor comes from observing biological systems. In cells, proteins do work by converting chemical energy stored in adenosine triphosphate (ATP) to mechanical work. During such work, proteins themselves evolve and pass through a complex viscous medium such as cell cytoplasm. This evolution and passage of proteins through cytoplasm is akin to random movement of a particle in a fluid — Brownian motion.
Based on the knowledge of Brownian motion, and taking into account thermodynamically open systems sensitive to external fluctuations arising from the environment, the researchers developed a model in which a particle of unit mass moves between two heat baths kept at different temperatures. The system extracts energy through thermal fluctuations from one of the baths and works against the viscous drag by moving in the direction of temperature gradients produced by the simultaneous presence of the second bath.
The results of the study may be realized experimentally in nanostructures where quantum effects play a significantly dominant role. The researchers say that the model may be utilized to develop microscopic engines to explain a vast majority of biologically active processes, creating nanoscale devices for carrying out directed mass and energy transport across membranes and even constructing a quantum information engine.
The authors of this work are from: Department of Chemistry, Bengal Engineering and Science University, Shibpur, Howrah and Department of Physics, Katwa College, Burdwan, West Bengal, India.