Oct 23, 2007 8:00 AM

Microscopic "hands" are in his grasp

The four tiny "fingers" gently open and close, looking much like a Venus flytrap collapsing around its prey. The "bones" of the fingers are shiny pieces of silicon; the "muscles," polymer balloons. The balloons are connected by narrow channels through which air is pumped in or out, allowing operators to manipulate the diminutive digits by regulating the air pressure: Increase the air pressure and the fingers close; release the pressure, and the fingers relax.

Just one millimeter wide, the microhand — the brainchild of Chang-Jin (CJ) Kim, professor of mechanical and aerospace engineering at the UCLA Henry Samueli School of Engineering and Applied Science — appears as a mere dot to the naked eye. Its minuscule size allows it to handle microscopic objects, which may one day make it an invaluable tool in microsurgery.

For now, though, the dexterity of the microhand has been demonstrated on — of all things — sushi. The tiny roe of smelt mimic many 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 said. "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."

In the early 1990s, the microhand was simply a "hobby" project for Kim, who maintained it off and on while focusing on many other projects that were well funded and more attainable. As the field of micro-electro-mechanical systems (MEMS) matured in the late 1990s, however, new microfabrication technologies reopened the door. Kim enlisted the help of Ph.D. student Yen-Wen Lu — now an assistant professor at Rutgers University — who worked for three years developing the current generation of hands.

News of the microhand spread quickly, and before long, Kim's team collaborated with Ritsumeikan University to demonstrate the hand at Expo 2005 in Aichi, Japan. The following year, the microhand made the cover of Applied Physics Letters, a premier journal in science and engineering.

The project took a serious turn when it attracted the attention of R&D company Intelligent Optical Systems, Inc. (IOS), based in Torrance. Along with IOS' interest came government funding.

Kim's current Ph.D. student, Wook Choi, is working on a larger hand (about five millimeters wide — five times bigger than the previous microhand) that will accommodate the applications IOS has developed. For instance, the hand can be used as a medical tool to remove foreign objects from a child's esophagus. Working with IOS, Choi also recently demonstrated the first microhand prototype with an eye at the center of the "palm," so that the operator has a direct view from the hand.

The hand can also be used to pick up and place tiny electronic circuit components, whose irregular shapes make such tasks difficult using routine, stiffer tools. Next, the team will pursue the delicate task of dismantling explosives.

"We finally have a real project, one that's funded," Kim said. "Engineers can dream, but dreaming is not enough — you have to put money into it. We're using taxpayers' money most times, so you can't just do it for fun. But this has been a lot of fun. I feel guilty!"

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