(CNN) Imagine a swarm of microscopic robots, so tiny that a teaspoon can hold billions of them.

They are ready to be injected into the most delicate areas of a human body -- the heart and the brain -- to deliver drugs with extreme precision or work like an army of nano surgeons, operating from within.

If it all sounds like science fiction, that's because it is: the plot of the 1966 sci-fi classic Fantastic Voyage revolves largely around this concept.

In the film, four people board a miniaturized submarine to enter the bloodstream of an American scientist, left comatose by the Russians as a result of a Cold War quarrel over the technology. They only have an hour to remove a life-threatening blood clot before they return to full size. The crew manage to escape the body in the nick of time via a teardrop.

But reality has a way of catching up with our fantasies , and nanotechnology is yet another field of science that bears that promise.

At ETH Zurich , the Swiss Federal Institute of Technology, mechanical engineer Brad Nelson and his team have worked on nanobots for a decade, and are now ready to think big: "We're making microscopic robots that are guided by externally generated magnetic fields for use in the human body," he told CNN.

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A little knife

The first to suggest that you could one day "swallow the surgeon" was beloved physicist and Nobel Prize winner Richard Feynman. He coined the idea in the provocative 1959 talk "There's plenty of room at the bottom" , which is widely considered the first conceptual argument for nanotechnology.

"You put the mechanical surgeon inside the blood vessel and it goes into the heart and 'looks' around," Feynman said, "It finds out which valve is the faulty one and takes a little knife and slices it out."

Nelson's microrobots might not yet have a little knife, but they sure have something special: their shape is inspired by the common E.coli bacteria, which is propelled by a rotating "tail" called the flagellum.

"Bacteria have a rotary motor," he explains, "Now, we can't make that motor, we don't have the technology for that, but we can use magnetism to move these things, so we actually take these flagella and we magnetize them, which allows them to swim."

The nanobots have already been tested "in vivo" in an extremely delicate environment, the eye. They can swim through the vitreous humor -- the clear gel that fills the eyeball -- and deliver drugs in the retinal area to treat age-related diseases such as macular degeneration, which can cause blindness.

At the heart of the matter

The robots are made in a "clean room" environment to keep them sterile, much in the same way as computer chips.

Nelson says that the test done with eyes have inspired other potential applications, such as the treatment of heart conditions. In this case the nanobots would be guided through a catheter - 2 to 3 millimeters in diameter - to reach the specific part of tissue that needs to be treated.

The catheter technique could also be used to reach the brain, and other target area include the smaller intestine and the urinary track. All difficult to reach areas where precision is a must. For that very reason, nanotechnology has long been touted as our best future weapon against cancer

But how would surgeons operate with nanobots?

"They would need training to learn how to use them," says Nelson, "but it's kind of an intuitive interface, and the nanobots would be guided with a joystick."

The technology is ready for the first clinical tests on human patients, which will begin to take place this year, according to Nelson.

Beyond medicine

"More recently people in the field have been looking at other applications like water treatment or environmental cleanup, where you might be able to operate hundreds, thousands, millions of these devices and have them swim through polluted water, catalyze pollutants, and then collect them back," he says.

This could be applied for example to oil spills: "There have been some recent publications that have shown how they can actually attach to oil droplets and move them to other locations."

But the most outlandish prediction on the use of nanotechnology comes from MIT's digital guru Nicholas Negroponte, who believes that in the future we will receive information and knowledge directly from nanobots that will swim up to our brain from within our bloodstream.

We'd love to hear what Richard Feynman would have had to say about "swallowing the teacher."

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