Tiny nanomotors have been controlled inside living cells for the first time ever, in a medical advance that could have far-reaching consequences.

This breakthrough was accomplished by researchers from Penn State University. Both chemists and engineers worked together on the project.

The nanomotors move through human cells using ultrasonic waves, and are steered using magnets. They look like tiny torpedoes, and hit the sides of cell walls as the travel through the structure.

"As these nanomotors move around and bump into structures inside the cells, the live cells show internal mechanical responses that no one has seen before. This research is a vivid demonstration that it may be possible to use synthetic nanomotors to study cell biology in new ways," Tom Mallouk, material chemistry and physics professor, said.

Tiny motors like these were first predicted in the science-fiction story Fantastic Voyage, written by Otto Klement and Jerome Bixby. Isaac Asimov wrote the screenplay for the 1966 film of the same name. In the fictional story, five medical researchers shrunk down to a tiny size, and were injected into the body of a scientist with a brain tumor.

Such miniature motors may be able to delivery drugs directly to cells in real life, without affecting other cellular structures. Similar motors have been tested before, but never before within human cells. Scientists working at Penn State developed miniature robots ten years ago, controlled by chemicals. Mallouck worked on that team, as well. However, those nanomotors were directed using toxic chemicals and would not travel through biological fluids. This made the first generation of tiny motors unsuitable for use in living beings.

Researchers tested the latest motors with a type of cancer cell called HeLa. These tiny cells engulfed the nanomotors when they were introduced into tissue. There was little action from the nanomotors when ultrasonic waves were first turned on. When they added more power to the system, the motors started moving and nanomotors could be used to tear apart the internal structures within cancer cells, or puncture their walls, destroying the organelles.

"One dream application of ours is Fantastic Voyage-style medicine, where nanomotors would cruise around inside the body, communicating with each other and performing various kinds of diagnoses and therapy," Mallouk said.

The study was funded by the National Science Foundation and the National Institutes of Health. An article detailing the development and testing of the nanomotors was published in the journal Angewandte Chemie International Edition on 10 February.