While this age of nanobots it not with us yet, a tiny, inexpensive motor with manufacture, may become the motive force in micromedical applications in the near future, according to Penn State engineer.
The smallest of these ultrasonic, piezoelectric motors developed by researchers at Penn State's Materials Research Institute is about the size of a grain of rice. They are 1.8 mm in diameter and 4 mm long.
Tiny, but powerfull, the smallest motor's rotation can just be stopped with the pressure of thumb and forefinger, but those only slightly larger will tear the skin and draw blood. "Initially, our applications for these motors are aimed at medical uses," says Dr. Kenji Uchino, professor of electrical engineering.
Some of these applications include specialized urinary catheters and endoscopic instruments. Currently, catheters with instruments to break up kidney stones, must be about 3 mm in diameter to accommodate the instruments. The 1.8 mm diameter motor would allow the catheter to become smaller and consequently more comfortable. The motor itself has sufficient power to break up kidney stone materials. An other application, although one not requiring such a small motor, would be on the end of an endoscope.
A mirror could be controlled by the motor to allow the light delivered by the fibre optic filament to illuminate a larger area of the upper digestive tract and physicians to view larger areas. "Also, because these motors are not electromagnetic, but electromechanical or piezoelectric, they are inherently non magnetic, which, with proper choice of materials, would allow them to be used in surgery performed using magnetic resonance imaging," says Uchino.
Initially, piezoelectric motors were made with tubes of piezoelectric materials, but they proved too expensive. Now, Uchino chooses aluminum, stainless steel, plastic or brass tubes that are readily available off the shelf. With the proper mateirals, the motors can be inexpensively manufactured and tailored to a variety of applications.Besides medical applications, they could function in appliances, computers and even wrist watches. The piezoelectric motors rotate much slower so watches powered by piezoelectric motors would be mechanically simpler.