Bioweapon Sensor Mirrors "Star Trek" Tricorder

Richard A. Lovett
for National Geographic News

July 11, 2006

A new sensor being developed can detect bioweapons in sealed packages from a short distance away—calling to mind Star Trek's handheld scanning devices known as tricorders.

The bioweapon sensor was co-developed by physicist John Miller, Jr. at the University of Houston, Texas.

The futuristic device, conceived after the September 11, 2001, terrorist attacks, is meant to detect life signs in a sealed container without the risk of opening the suspect package (related feature: Inside 9/11 TV preview).

It can detect such signals from a sort distance—about two-fifths of an inch (a centimeter) away.

The sensor leverages the fact that biochemical reactions in cells emit electrical signals. These can be detected by scanning cells with oscillating, low-voltage electrical fields.

Miller notes, for example, that cells from green plants produce a distinctive signal when exposed to light.

"We see a response when the light is on, but not when the light is off," Miller said at a meeting last month of the American Geophysical Union in Baltimore, Maryland.

Specifically, Miller is detecting photosynthesis in action.

The device is only one example of promising technology being developed in the growing field of biogeophysics.

The science applies remote-sensing techniques—normally used for studying rocks, planetary atmospheres, or buried archaeological sites—to living organisms.

From Cancer to ET

In addition to photosynthesis, other signals the life-signs sensor could detect appear to relate to different cellular processes.

For example, the molecule adenosine triphosphate (ATP) is a main energy source in many living cells, Miller says.

One of the enzymes involved in the chemical reaction that creates ATP spins at several hundred revolutions per second, creating a distinctive electrical signature.

Previously, the only way scientists could detect such activity was to insert probes into cells, but current technology limits how small such probes can be.

Miller compares today's probing procedures to "taking a two-inch pipe and jamming it into your body to make measurements."

"Our [technique] is mechanically noninvasive," he said. The scientist envisions many potential uses for the new sensing technology once it is perfected.

Miller notes, for example, that cancer cells behave differently from normal ones.

This opens the door for new medical scans that could detect the disease early on, particularly lung cancer "which often isn't detected until a late stage," he said.

The physicist believes similar technology could one day power "life detectors" used to search for extraterrestrial organisms (read excerpys from "Life Beyond Earth" in National Geographic magazine [January 2000]).

An advantage of such devices, Miller says, is that they don't have to be tuned for predetermined biological markers, such as DNA or proteins.

A unit outfitted on a Mars rover, for example, wouldn't need to know precisely what biological processes it was observing—only that that it was detecting the biochemical action of a living organism.

But whether the scanning technology can be sufficiently miniaturized for passage aboard space rovers remains to be seen.

Peering Deep

Estella Atekwana of the department of geological sciences and engineering at the University of Missouri-Rolla envisions more terrestrial applications for biogeophysics.

Atekwana, who was not involved in the bioweapon sensor project, says biogeophysical scanners might probe for microbial activity beneath the Earth's surface.

Such applications are theoretically possible, she says, because bacterial layers alter the electrical conductivity of soil. Microbe layers also alter the way that soil and rock transmit sound.

Atekwana says such scanners might also be used to monitor cleanup of hazardous waste sites via a process called bioremediation—bacteria converting toxic pollution in soils into less-harmful substances.

(Related news: "Bacteria May Be Star Player in Toxic Cleanup" [November 2004].)

"Are the bacteria doing what they're supposed to be doing?" Atekwana said. A biogeophysical scanner could answer such questions.

But the scientist believes the technology will likely see its most important use in microbially enhanced oil recovery.

Atekwana notes that most remaining U.S. oil reserves contain so-called heavy oil, which is difficult to get out of the ground.

Microbially enhanced oil recovery uses petroleum-eating bacteria to convert this oil into a more easily extractable form.

"It would be good to know the health of the bacteria," she said, "whether they're doing their job and going to the right places."

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