Researchers at the Cockrell School of Engineering at The University of Texas at Austin say they have built the smallest, fastest and longest-running synthetic motor to date. The  nanomotor is a step toward 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, the researchers said.

With the goal of powering these yet-to-be invented devices, UT Austin engineers focused on building a reliable, ultra-high-speed nanomotor that can convert electrical energy into mechanical motion on a scale 500x smaller than a grain of salt. The three-part nanomotor can rapidly mix and pump biochemicals and move through liquids, which is important for future applications, said associate professor and lead researcher Donglei Fan.

The motor’s dimensions are less than 1µm, and it can operate for 15 continuous hours at a speed of 18,000 RPMs. 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, the researchers said.

Looking forward, nanomotors could advance the field of nanoelectromechanical systems (NEMS), an area focused on developing miniature machines that are more energy efficient and less expensive to produce. In the near future, the Cockrell School 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.”

The researchers addressed two major issues for nanomotors: assembly and controls. The team built and operated the nanomotor using a patent-pending technique that Fan invented while studying at Johns Hopkins University. 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 synchronized fashion to increase power capacity.

Fan and her team plan to develop new mechanical controls and chemical sensing that can be integrated into nanoelectromechanical devices. But first they plan to test their nanomotors near a live cell, which will allow Fan to measure how they deliver molecules in a controlled fashion.

Source from: Micro Manufacturing Magazine