Small Wonder

The four tiny "fingers" gently open and close, like a Venus flytrap collapsing around its prey. The "bones" are shiny pieces of silicon; the "muscles," polymer balloons connected by narrow channels through which air is pumped in or out, allowing researchers to control the diminutive fist, only one millimeter wide, by regulating the air pressure. This "microhand" is a deft manipulator of tiny objects and one day may be an invaluable tool in microsurgery.

For now, though, the dexterity of the microhand, the brainchild of Chang-Jin (CJ) Kim, professor of mechanical and aerospace engineering at the Henry Samueli School of Engineering and Applied Science, has been demonstrated on — of all things — sushi.

The tiny roe of smelt mimic other objects in biological environments, and the microhand has proven very adept at delicately capturing and removing a single egg from the rest of the gooey pack. "When you work in microscale, stickiness is an issue," Kim says. "And you're dealing with a liquid environment that is very viscous, like honey. Our hand is able to grab a soft and delicate object and mold itself around it. Yet it's very strong."

Kim laughs when he recalls the origins of his research. "When I started grad school, MEMS (micro-electro- mechanical systems) was a new field," he says. "I wanted a micro-robot that could do everything a human could do if the human were miniaturized," Kim recalls. Yet he soon realized that "the technology just wasn't available. So the goal got smaller and smaller — from a micro-robot, to a microhand, to a pair of micro-tweezers."

When he joined UCLA in 1993, Kim maintained his "hobby" project. As MEMS science matured, however, Kim enlisted the help of Ph.D. student Yen-Wen Lu — now an assistant professor at Rutgers University — to build the current generation of hands.

The project attracted the attention of R&D company Intelligent Optical Systems, Inc. (IOS), in Torrance, Calif., and government funding has followed. Kim's current Ph.D. student, Wook Choi, is working on a larger hand that will accommodate applications IOS has developed, such as removing foreign objects from a child's throat.

"Dreaming is not enough," Kim says. "You have to put money into it. We're using taxpayers' money, so we can't just do it for fun. But this has been a lot of fun. I feel guilty!"