Nanomotors in vivo: Tiny motors set to motion in live human cells

For the first time tiny rocket-shaped synthetic motors have been placed inside live human cells. What has been a staple of science fiction is now a promising method to treat cancer, US scientists say.

The researchers from Penn State University have successfully embedded synthetic nanomotors into HeLa cells, an immortal line of human cervical cancer cells typically used in research studies, according to a press release published on the university’s website.

"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," said Tom Mallouk, Evan Pugh Professor of Materials Chemistry and Physics at Penn State. The findings were published in the journal Angewandte Chemie International Edition on Monday.

Until now the researchers studied nanomotors only "in vitro” - in a laboratory apparatus, said Mallouk, adding that the experiment in human cells was performed for the first time.

Similar nanomotors were developed at Penn State University ten years ago, however they were chemically powered and could not move in cells.

"Our first-generation motors required toxic fuels and they would not move in biological fluid, so we couldn't study them in human cells," Mallouk said. "That limitation was a serious problem."

Then the research team made a breakthrough by discovering that the ‘tiny rockets’ could be powered by ultrasonic waves.

Using low ultrasonic power the nanomotors have little effect on the cells, however when the power is increased they start actively moving “bumping into organelles - structures within a cell that perform specific functions,” Mallouk explained.

“The nanometers can act as egg beaters to essentially homogenize the cell's contents, or they can act as battering rams to actually puncture the cell membrane,” according to the press release.

In addition to the fact that researchers managed to control the motors by steering them, Mallouk and his colleagues also discovered that the nanomotors can move independently of one another.

"Autonomous motion might help nanomotors selectively destroy the cells that engulf them," Mallouk said. "If you want these motors to seek out and destroy cancer cells, for example, it's better to have them move independently. You don't want a whole mass of them going in one direction."

The breakthrough has potential for the development of medicine, such as intracellular surgery and the delivery of drugs noninvasively to living tissues, Mallouk believes.

“We might be able to use nanomotors to treat cancer and other diseases by mechanically manipulating cells from the inside.”

"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. There are lots of applications for controlling particles on this small scale, and understanding how it works is what's driving us."