We can learn from nature:
Inspired by the sleek and efficient propulsion of squid, jellyfish and other cephalopods, a University of Colorado at Boulder researcher has designed a new generation of compact vortex generators that could make it easier for scientists to maneuver and dock underwater vehicles at low speeds and with greater precision.
In addition, the technology — seemingly inspired by the plots of two classic sci-fi films — may soon allow doctors to guide tiny capsules with jet thrusters through the human digestive tract, enabling them to diagnose disease and dispense medications.
(The two films, by the way, are Fantastic Voyage and Inner Space; I think only the former classifies as an SF classic.)
While the details are awfully thin, there are more pictures and movies online. Hint—don’t waste your time with the mpgs, they only show the titles; you’ll have to watch the ugly wmv files.