From Electrical to Fuel Powered Artificial Muscles
From: NNEC 2007 Presentation Abstracts

The team at the University of Texas experimentally demonstrated artificial
muscles that convert the energy of a high-energy-density fuel to mechanical
energy. These muscles are fuel cells that in some embodiments store
electrical charge and use changes in stored charge for mechanical actuation.
The highest demonstrated actuator generated strains and mechanical output
power densities are comparable to natural skeletal muscle, and the actuator
generated stresses are over a hundred times higher than for natural skeletal
muscle. Since the energy density of fuels like methanol is about 30 times
higher than for advanced Li batteries, this advance is important for such
applications as autonomous robots or prosthetic limbs, where long operation
without recharging or refueling is needed. 

From:
http://www.nasatech.com/nano/abstracts.html#MBaughman

Links:
Fuel-Powered Artificial Muscles
http://www.sciencemag.org/cgi/content/full/311/5767/1580

Ray H. Baughman
http://nanotech.utdallas.edu/personnel/staff/baughman.html