From Physorg.com, a description of some theoretical nanotechnology work that could lead to more efficient molecular machines:
…R. Dean Astumian, a Physics Professor at the University of Maine, has recently proposed a concept in which molecular machines can operate arbitrarily close to chemical equilibrium at every instant of the cycle, and still perform work at the rate of several micrometers per second against piconewton loads…
“The main significance is conceptual – it changes the way we think about molecular motors,” Astumian told PhysOrg.com. “Much emphasis has been put on the ‘non-equilibrium’ aspects of the system, but in fact this is not really important. The motion of the rings here arises due to a combination of topology that break spatial symmetry, and the slow external modulation that breaks time symmetry. It is also important to recognize that, in the molecular world, we can truly have motors that operate with nearly 100% efficiency”…
Astumian also explains that operating this system requires a fine balance between modulating slowly enough so that the system is in chemical and mechanical equilibrium at every instant, but rapidly enough to perform substantial work. While biomolecular motors are often described in “violent” terms, he hopes that this “kinder, gentler” description may be more appropriate for designing more efficient molecular machines.
Making nanotech machines more efficient is good, in general. But not all molecular machines need to be gentle. Sometimes the ability to exert significant force could be useful. —Christine
