THE DALLAS MORNING NEWS
August 4, 1997, Monday, HOME FINAL EDITION DISCOVERIES; Pg. 10D
The chips are up
Chemists' development of miniature lab on silicon wafer may pay off for science
Jeffrey Chuang, Staff Writer of The Dallas Morning News
The test tube, like its cousin the vacuum tube, could be headed for oblivion. And
the assailant of aging technology is, once again, the agile silicon chip.
Professor Fred Regnier and graduate student Bing He of Purdue University
have built a partial chemistry lab on a small silicon wafer, the same object used
to make a computer chip. Their work may eventually help phase out traditional lab
equipment and enable chemists to do experiments with the lightning speed and precision
of a computer.
"The very technology that was used to create and construct the computer chip can
be used to construct these mini-laboratories," says Dr. Regnier. The researchers
presented their work last month at the International Symposium on Column Liquid
Chromatography in England.
The work is a promising step toward the decade-old concept of "laboratory-on-a-chip,"
in which scientists have envisioned thousands of chemical experiments running simultaneously
on a plate just centimeters wide, he says.
By combining chemical processes with circuits on such a chip, such microlabs could
someday allow scientists to do a chemical experiment by typing a command at the
keyboard, says J. Michael Ramsey, a chemist at Oak Ridge National Laboratory in
Tennessee.
The first benefit of these chips will be to bring some of the mercurial speed
of computers to a chemist's laboratory, says Dr. Regnier.
Scientists spend a lot of time doing repetitive experiments, one after another.
But if several laboratories are built on a single chip, chemists will be able
to do many experiments at once - just as a computer can do more than one calculation
at a time if it has several microprocessors.
If 100 experiments are placed on a single chip, then researchers will be able to
perform 100 times as many experiments as they can now, says Dr. Regnier. And even
more experiments could be packed on a chip if the need arose.
The technology, which is a few years away from maturity, is likely to be embraced
by drug companies, who must drone through thousands of nearly identical experiments
in the process of screening new drugs.
"What you realize is that if it takes five to 30 minutes to do one sample . . .
it takes a long time. What do you do if you are a drug company that wants to do
1,000 of these a day?" says Dr. Regnier.
The fine process by which Dr. Regnier and Mr. He sculpt their chips has been used
by computer chip engineers for decades. The chemists etch patterns into a silicon
chip by coating the chip with a chemical, selectively exposing the chip to light,
and then washing the chip with an acid.
The chips the chemists work with are quartz, more scientifically known as silicon
dioxide.
Scientists can chemically scratch structures into the chip to a precision better
than a micron, about one-hundredth of the width of a human hair.
While computer engineers use the process to draw circuit layouts, the Purdue
researchers craft microscopic mimics of flasks, beakers and test tubes. Channels
several microns wide convey chemicals from one receptacle to another.
"You have to duplicate what you do in the macroscopic world in the microscopic
world," Dr. Regnier says.
The scientists have focused their work on a particular laboratory technique known
as chromatography. Chromatography is a process by which chemicals in a solution
are separated from each other. The technique is used in a multitude of experiments,
and will probably be one of the first areas of application for microlaboratories.
"It would be difficult to find a laboratory without chromatography," says Dr.
Regnier.
In chromatography, a chemical solution flows through a channel of grainy mounds,
much as a river flows over rocky rapids. Because different chemicals in solution
bounce off the mounds differently, each chemical gets to the end of the channel at
a different time.
The Purdue
scientists' key discovery was a now-confidential method of building microscopic
mounds on the chips.
That research adds another working component to the lab-on-a-chip concept, says
Dr. Ramsey. Most of the basic scientific questions are being resolved, and after
that only engineering concerns will remain, he said.
The researchers developed their technology with the biotechnology company PerSeptive
Biosystems, which Dr. Regnier co-founded.
Other private companies are providing fierce competition for lab-on-a-chip research.
The chips' potential for speeding up commercial drug discovery is a huge incentive.
In the multibillion-dollar drug business, a one-year advance in discovering a new drug can be worth a billion dollars, says Dr. Regnier.
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