Researchers at Purdue University have created a magnetic "ferropaper" that might be used to make low-cost "micromotors" for surgical instruments, tiny tweezers to study cells and miniature speakers.

The material is made by impregnating ordinary paper - even newsprint - with a mixture of mineral oil and "magnetic nanoparticles" of iron oxide.

"Paper is a porous matrix, so you can load a lot of this material into it," said Babak Ziaie, a professor of electrical and computer engineering and biomedical engineering.

The new technique represents a low-cost way to make small stereo speakers, miniature robots or motors for a variety of potential applications, including tweezers to manipulate cells and flexible fingers for minimally invasive surgery.

"Because paper is very soft it won't damage cells or tissue," Ziaie said. "It is very inexpensive to make. You put a droplet on a piece of paper, and that is your actuator, or motor."

Once saturated with this "ferrofluid" mixture, the paper is coated with a biocompatible plastic film, which makes it water resistant, prevents the fluid from evaporating and improves mechanical properties such as strength, stiffness and elasticity.

Findings will be detailed in a research paper being presented during the 23rd IEEE International Conference on Micro Electro Mechanical Systems on Jan. 24-28 in Hong Kong. The paper was written by Ziaie, electrical engineering doctoral student Pinghung Wei and physics doctoral student Zhenwen Ding.

Because the technique is inexpensive and doesn't require specialized laboratory facilities, it could be used in community colleges and high schools to teach about micro robots and other engineering and scientific principles, Ziaie said.

The magnetic particles, which are commercially available, have a diameter of about 10 nanometers, or billionths of a meter, which is roughly 1/10,000th the width of a human hair. Ferro is short for ferrous, or related to iron.

"Purdue researchers have created a magnetic "ferropaper" that might be used to make low-cost "micromotors" for surgical instruments, tiny tweezers to study cells and miniature speakers. Babak Ziaie, a professor of electrical and computer engineering and biomedical engineering, holds a miniature birdlike shape made from the material. The wings move slowly, but the structure is not capable of flight. (Credit: Purdue University photo/Andrew Hancock)"

Source: Purdue University