 |
As the cruiser powers into an enemy
harbor the captain, suspecting mines, unleashes a swarm of
microbes into the water. By the trillions they sniff out TNT,
fluorescing brighter hues of red as they near their quarry and
then digest the explosive, rendering it harmless.
Sounds far-fetched, but if Princeton University
bioengineer Ron Weiss has his way, within the next 10 years
the first generation of man-made bacterial robots, or
microbots, not only will detect dynamite but will scrub carbon
dioxide from smokestack emissions, diagnose disease, and
siphon hydrogen from water for fuel.
The microbots'
chore list is endless, says Weiss, who is at the forefront of
a small but sophisticated new field of genetic engineering
called synthetic biology. While traditional genetic engineers
shuffle genes from one organism to another, synthetic
biologists design and rewire complex networks of genes inside
a single organism--effectively reprogramming the genetic
pathways that control how the organism behaves. "You no longer
think about fixing a single gene; you think about putting in
whole sets of instructions," Weiss explains.
This June
scores of researchers, including Weiss, will convene for the
first-ever conference on synthetic biology, hosted by MIT.
Weiss, for one, is eager to get feedback on his newest
creation: bacteria programmed to measure concentrations of a
chemical and then form a bull's-eye around the source (see
graphic). "The impact of research like this will be
tremendous," says Eric Eisenstadt, who handles
synthetic-biology funding for the Defense Advanced Research
Projects Agency.
At the genetic level, bacteria use
many of the same tricks as computer circuitry. In a typical
genetic circuit, one gene produces a protein that turns a
corresponding gene on or off, much the way a computer inverter
turns a 1 into a 0 and vice versa. Switched on, a gene might
produce a chemical signal that directs an organism to seek out
food; switched off, it helps the organism conserve energy. By
plugging in proteins and genes, Weiss can activate or
deactivate chemical signals on command.
Weiss made his
first single gene circuit in 1997 as an MIT computer-science
graduate student. Since then his circuitry has become
increasingly complex. His newest work, the bull's-eye
bacteria, contains a circuit made of five genes. "It's
fascinating to think that you can make living organisms do
whatever you want," Weiss says.
Fascinating and
dangerous, says Stanford University bioethicist David Magnus.
Bacteria could be programmed to produce toxins instead of
mopping them up. Magnus argues that the new field needs strict
guidelines to ensure that microbots test safe before
scientists release them into the wild. Weiss acknowledges the
risks but says the more we learn about gene programming, the
better able we'll be to minimize the dangers.
|
|
.gif)
.gif){kind=spacer}
