- Pocket-sized DNA sequencers and full
forensics labs that can fit into briefcases are hitting the market this
year, replacing the cumbersome technology that botched police investigations
of serial killer Paul Bernardo and helped wrongly convict Guy Paul Morin
of murder.
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- The technology will allow police labs
to go to crime scenes. And, combined with new DNA databases that are being
built by most major governments, police will be able to run genetic searches
on potential suspects within minutes of the discovery of a crime scene.
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- Researchers say the new labs, based on
micro-fluidics and incredibly advanced computer chip technology, will do
for forensic and drug labs what the microcomputer did for mainframes. Backlogs
at DNA test labs, which delayed the capture of Mr. Bernardo by two years,
will be wiped out.
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- Some of the researchers compare the new
technology to Star Trek's "tricorder," devices that allow fictional
space explorers to test the biological makeup of aliens and the health
of humans with a palm-sized instrument.
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- Today's DNA labs require several table-top
sized machines to isolate DNA from tissue samples, find the fragment to
be analysed, amplify it and map its sequences. The chemicals used in the
process are expensive, and each machine needs its own technician.
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- But the new microlabs allow forensic
scientists to take the lab to the crime scene. Mini-DNA sequencers are
already being sold by Connecticut-based medical instrument maker Perkin-Elmer.
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- And the miniaturized "labs on a
chip" are useful for more than just DNA testing. They can be used
to test for air and water pollution, to look for new drugs, hunt for chemical
weapons and may even be sent on interplanetary missions. One "lab
on a chip" has already been used on a European Space Agency experiment
carried on a NASA space shuttle mission.
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- Jed Harrison, professor of chemistry
at the University of Alberta, is heading a 15-member research team developing
the new technology.
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- "We're doing planar micro-fluidics:
making the fluidic part of the lab miniaturized. On the microchip, you're
able to do things at higher speed," said Mr. Harrison. "The distances
are shorter, the volume is smaller. Where it might take half an hour to
do a chemical separation in a conventional laboratory, you can do the same
separation in five seconds or even in a millisecond on a chip.
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- "So just as a microprocessor integrates
a whole bunch of transistors together, and then combines memory functions
with calculating functions and adds them all together in a single structure,
we can take various kinds of chemical sample processing and do them in
different parts of the same chip. So we integrate the entire process.
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- "And they're at their best when
in cases where contamination can be important, working with DNA samples,
for example. One of the hazards in DNA samples is that the sample gets
exposed to the laboratory and gets contaminated by the lab, and then you
end up measuring the DNA of Joe Lab-technician instead of President Clinton."
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- Last May, a group of privately funded
scientists in the U.S. announced they would use the new microlab technology
to finish sequencing the entire human genome in three years, at a cost
of $300 million.
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- If they succeed, they will finish four
years earlier than the U.S. government's project to map human genetics,
and they'll do it at a tenth of the cost.
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- "You can integrate onto a chip lots
of channels parallel to each other," said Mr. Harrison. "So,
if you think of each channel representing a chemical system where you might
run some reactions and separations and measure your results, you can have
100 of those in parallel. You can get a really high number of data analyses
at once.
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- "By integrating all of these processes,
you get a system that is really amenable to automation. You have the ability
to make these things small enough and cheap enough -- in principle, but
not in practice yet -- to make them single-use, disposable elements."
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- Some of the new micro-labs can perform
as many as 600 tests or chemical reactions at once. Technicians use a tiny
amount of salt to break open tissue cells and release the DNA. A near-microscopic
sample is injected into the machine's storage chamber, and the machine's
computer does the rest of the work.
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- The nucleic acids stick to a small glass
wall, and the machine spits out the rest of the sample. The DNA gets three
rinses of ethanol and water. Then it moves into the next chamber, where
re-agent chemicals are mixed with it.
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- The DNA is then amplified and mapped
by the machine's computer. The process takes only a few minutes.
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- Wally Parce, research director of Caliper
Technologies, a micro-fluidics lab equipment company in Palo Alto, California,
says the new labs are chemistry's equivalent of the evolution of computers
from mainframes to laptops.
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- And the labs are as easy to use as a
personal computer, he adds.
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- Another practical use of the microlabs
is in medicine. Many genetic-based diseases aren't diagnosed quickly because
doctors can't find labs to do the tests. Or the results come back so slowly
that they're too late to help.
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- "DNA testing really isn't a medical
doctor's tool," says Mr. Harrison. "You can't wait that long,
usually. But, in about 10 years, genetic analysis will be a $10-billion-a-year
business."
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- Copyright 1998 Ottawa Citizen
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