World's smallest, fastest motor developed

Scientists have developed the world's smallest, fastest and longest-running tiny synthetic motor to date that can fit inside a cell and spin as fast as a jet engine.
The nanomotor is an important step towards developing miniature machines that could one day move through the body to administer insulin for diabetics when needed, or target and treat cancer cells without harming good cells, researchers said.
Engineers from the Cockrell School of Engineering at The University of Texas at Austin focused on building a reliable, ultra-high-speed nanomotor that can convert electrical energy into mechanical motion on a scale 500 times smaller than a grain of salt.

Mechanical engineering assistant professor Donglei "Emma" Fan led a team of researchers in the successful design, assembly and testing of the high-performing nanomotor in a nonbiological setting.
The team's three-part nanomotor can rapidly mix and pump biochemicals and move through liquids, which is important for future applications.
Fan and her team are the first to achieve the extremely difficult goal of designing a nanomotor with large driving power.

With all its dimensions under 1 micrometre in size, the nanomotor could fit inside a human cell and is capable of rotating for 15 continuous hours at a speed of 18,000 RPMs, the speed of a motor in a jet airplane engine.

Comparable nanomotors run significantly more slowly, from 14 RPMs to 500 RPMs, and have only rotated for a few seconds up to a few minutes.
Researchers believe their nanomotors could provide a new approach to controlled biochemical drug delivery to live cells.
To test its ability to release drugs, the researchers coated the nanomotor's surface with biochemicals and initiated spinning. They found that the faster the nanomotor rotated, the faster it released the drugs.
"We were able to establish and control the molecule release rate by mechanical rotation, which means our nanomotor is the first of its kind for controlling the release of drugs from the surface of nanoparticles," Fan said.

"We believe it will help advance the study of drug delivery and cell-to-cell communications," said Fan.
The technique relies on AC and DC electric fields to assemble the nanomotor's parts one by one.
In experiments, the researchers used the technique to turn the nanomotors on and off and propel the rotation either clockwise or counterclockwise.
The researchers found that they could position the nanomotors in a pattern and move them in a synchronised fashion, which makes them more powerful and gives them more flexibility.
The study was published in the journal Nature Communications.