WASHINGTON — The IEEE’s International Electron Devices Meeting is a pretty fluid event, with the various engineers and academics drifting from room to room, following the presentations that interest them. So when all the seats in the room you’re in suddenly fill up with people, you’re probably about to hear something interesting. This morning’s presentation by Ming C. Wu, from the University of California at Berkeley, was jammed to the gills with spectators to hear him describe his “optoelectronic tweezers.” Wu’s innovative tool is based on technology that was first created in 1986 by Arthur Ashkin of Bell Labs, who discovered a way to trap and hold atoms with laser light, using a phenomenon called radiation pressure.

This technology works well at the atomic level, but such a tightly focused beam of light won’t work on larger, more complex objects such as cells. Wu realized that laser light isn’t really necessary to trap and move objects at the microscopic level. Instead, Wu uses optically induced dielectrophoresis, in which a beam of light is converted into an electric field—sort of like a projected tractor beam. Wu’s process is far less demanding than the standard optical tweezers technique, and it can be accomplished with cheap LED light instead of expensive lasers. But it gets far more interesting: Wu’s electric light tweezers can be projected onto a laboratory specimen slide in a variety of patterns, including boxes that serve as cages for cells and even movies that can move multiple cells around at a time, forming an optoelectronic “conveyor belt.”

This stuff isn’t entirely new: Wu first presented his research in an article in Nature in 2005, but today’s presentation showed that he’s been expanding the concept. He’s now shown that the optoelectronic tweezers process can be used to manipulate nanowires and other tiny objects. The process has obvious utility in lab work, simplifying tasks such as separating dead cells from live ones and isolating individual cells that, with today’s clumsy tools, can be extremely difficult. —Glenn Derene

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