Researchers at the University of Delaware have found a way to activate nanotubes using only light as a stimulus,

"In our experiments, we discovered independently that if we shone light on nanotubes, they would move," said UD professor Balaji Panchapakesan in a report at EE Times:

Micro-opto-mechanical systems (MOMS) use lasers to actuate tiny mirror-tipped cantilevers instead of the electrical current needed for pneumatic, piezoelectric or electrostatic actuators. An optically active nanotube film enables MOMS to be actuated by an ultralow-power laser instead of a power-draining electrical current.

The researchers say that MOMS has low enough power consumption for space exploration and could enable new applications for field-emission displays and biomedicine.