|Posted on May 28, 2014 at 11:05 PM|
Using nanorobots for attacking cancerous cells or delivering drugs might seem like a topic for science fiction. And indeed, it has been difficult to develop automated nanoelectromechanical systems (NEMS) structures for biomedical applications that are efficient and stable enough to be used in actual applications.
Rotary nanomotors are of particular interest for harvesting energy and precisely releasing drugs. However, building rotary motors at a nanoscale imposes many challenges. Traditional MEMS technology requires hundreds of fabrication steps and restricts the size of the devices to hundreds of micrometres, making them undesirable for biomedical applications.
In a recent article in Nature Communications, Prof. Donglei "Emma" Fan (Mechanical Engineering, U. Texas, Austin), and her research group demonstrated a breakthrough technology to build rotary nanomotors, showcasing the world's smallest and fastest nanomotors. They used nanoscale building blocks - multisegment nanowires, patterned nanomagnets and quadrupole microelectrodes to assemble a nanomotor. For this precise task, they used "electric tweezers," another invention from Prof. Fan, a nanomanipulation technique to transport nanoentities. Electric tweezers can transport nanowires and nanotubes with a precision of 150 nm, and rotate them. The technique utilizes AC and DC electric fields to assemble the nanomotors. Prof. Fan's team showed that they can build arrays of nanomotors smaller than 1 micron in dimension, and can rotate for 15 hours for more than 240,000 cycles with precise directional control and biochemical release. Using nanorobots to deliver drugs to treat various diseases may no longer appear in science fiction.
(The four authors of the Nature Comm paper, Kwanoh Kim, Xiaobin Xu, Jianhe Guo, & D. L. Fan.)
(Photo credits: Provided by and used with permissions from Prof. Fan)