Researchers: Molecular forklifts overcome obstacle to 's...( GAINESVILLE Fla. --- Algae is a livi...)

GAINESVILLE, Fla. --- Algae is a livid green giveaway of nutrient pollution in a lake. Scientists would love to reproduce that action in tiny particles that would turn different colors if exposed to biological weapons, food spoilage or signs of poor health in the blood.

Now, University of Florida engineering researchers have tapped the working parts of cells to clear a major hurdle to creating such "smart dust." The feat, which signifies a new approach to technology known as the "lab on a chip," is to be reported Sunday in the journal Nature Nanotechnology.

"Instead of just changing one part of an existing system, we have a new and different way of doing things," said Henry Hess, a UF assistant professor of materials science and engineering and the senior author of the paper. "And we can do it this way because of building blocks from bionanotechnology, and that's what makes it very exciting."

Chip-based labs have been developed in recent years as portable tools to gauge the presence of bioweapons, pollution, or to conduct on-the-spot blood tests. They are essentially assays, or ways to test for different pathogens, chemicals or compounds.

Scientists have suggested that the ever-shrinking labs could be reduced to the size of tiny particles of "smart" dust. But although today's versions may be small, they require equipment that is hand-held at its smallest, and often large enough to require a lab bench.

"It's like a computer," Hess said. "The central processing unit is the really interesting thing, but you need all this other stuff to make it work."

The extra equipment is needed because the assay, which uses pairs of antibodies to latch onto target contaminants and the markers that give away their presence, requires repeated flushing with water. That requires pumps, which need power. To miniaturize the system, it's necessary to build miniature pumps and batteries. But that's a challenge, especially for
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