Researchers have place synthetic motors in live human cells for the first time.
The "rocket-shaped metal particles" bump against the cell membrane, allowing them to be steered magnetically, a Penn State news release reported.
"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," Tom Mallouk, Evan Pugh Professor of Materials Chemistry and Physics at Penn State, said in the news release. "This research is a vivid demonstration that it may be possible to use synthetic nanomotors to study cell biology in new ways. We might be able to use nanomotors to treat cancer and other diseases by mechanically manipulating cells from the inside. Nanomotors could perform intracellular surgery and deliver drugs noninvasively to living tissues."
In the past these nanomotors have only been studied in vitro in a lab apparatus, never in a living cell. These chemically powered nanomotors were first discovered a decade ago at Penn State.
"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."
The discovery that these motors could be powered with ultrasonic waves allowed them to put to work in human cells.
The team used HeLa cells (an "immortal line" of cervical cancer cells) to make their findings.
The nanomotors move around the cells through ultrasonic waves; when the power of these waves is increased the cells spring into action and bump into organelles (which perform specific functions within the cells). The nanomotors can "homogenize the cell's contents" or even puncture the cells' membranes.
The ultrasound pulses allow researchers to control if the nanomotors spin or move forward, but, magnetic forces allow them to be controlled even further. The cells can also move independently of each other.
"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."
"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," he said.
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