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ORNL is Developing "Chemistry Lab on a Chip"


OAK RIDGE, Tenn., Dec. 12, 1994 — A "chemistry lab on a chip" might seem like a researcher's dream, but recent successes at the Department of Energy's Oak Ridge National Laboratory (ORNL) suggest it could become a reality.

A postage-stamp-size microchip for efficiently separating and identifying chemicals in liquids is being developed by ORNL scientists. They have used the device to separate chemicals in a liquid drop in as little as 150 milliseconds. Such a device could have widespread use in the environmental, manufacturing, health care, and pharmaceutical industries. The ORNL researchers have also shown that microscopic devices can be used to carry out chemical reactions. The work suggests that an entire chemistry laboratory, including chemical containers, beakers for mixing chemicals, and analysis instruments, could be placed on a microchip. "Such a microchip laboratory could provide faster, cheaper, and more reliable chemical analyses for environmental monitoring, industrial process control, and medical diagnosis," said J. Michael Ramsey, one of the developers of the technology. "It could also be used by unskilled personnel to perform sophisticated chemical analyses in remote locations."

The laboratory on a chip offers several potential advantages over conventional approaches to chemical analysis. It would automate preparation of chemicals for analysis, saving labor and protecting people from unnecessary chemical exposure. Also, the amount of chemical reagents on a chip - substances needed to carry out chemical reactions - would be one-millionth of the typical volume used in a laboratory setting, thus minimizing chemical waste requiring disposal. In addition, because the miniaturized device has no moving parts, it should be more reliable and inexpensive enough to be disposable.

Thanks to its greatly reduced size and weight, the microchip laboratory could be incorporated into hand-held devices for surveying waste sites or diagnosing a patient's disease in a physician's office. It could also be part of a small sensor used in chemical process pipes to monitor and control production in a factory.

"One of our goals is to develop microdevices for chemical analysis that demonstrate the same advantages as microelectronics, including small size, low cost, high speed, reliability, and operational simplicity," says Ramsey. "Our results show that it is possible to reduce instrument size from a few cubic feet to several cubic centimeters, and that the performance of the miniaturized instruments is equivalent to or better than the conventional laboratory versions.

The chip is a glass plate as thin as a microscope slide and about the size of a postage stamp. A winding, hair-like capillary channel, covering an area the size of a dime, is etched in the glass using standard micromachining techniques. The etched channels are closed by bonding a thin plate of glass over the top.

Ramsey said that miniature chemistry labs on a chip could be integrated into a miniature chemical factory. Just as computers work at the same time on different parts of a complex problem, chemical analysis microchips could work in parallel to synthesize and test new drugs. "This approach," he added, "could speed the discovery of new drugs that are effective against disease."

Besides Ramsey, the developers of the microchip laboratory include Stephen C. Jacobson, Roland Hergenroder, Lance B. Koutny, and Alvin W. Moore, all of ORNL's Chemical and Analytical Sciences Division.

This work has been funded originally by the ORNL Director's Laboratory Directed Research funds and followed by support from the Department of Energy's Office of Nonproliferation and National Security.

ORNL, one of the Department of Energy's multiprogram research laboratories, is managed by Martin Marietta Energy Systems, which also manages the Oak Ridge K-25 Site and the Oak Ridge Y-12 Plant.

