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[S. Perkins, “Taste testing with an electronic tongue,” in Science News, vol. 157, 2000, pp. 126.

 

Taste testing with an electronic tongue

With the same techniques of pattern recognition used in many electronic noses, an electronic tongue can “taste” liquids that people can’t—or shouldn’t—put in their mouths, say researchers at the University of Texas at Austin. Chemist Eric V. Anslyn and his colleagues created a postage-stamp-size chemical-sensing device by drilling a series of small holes in a silicon wafer. They then placed a small poly styrene bead coated with one of several fluorescent materials in each hole. Each bead acts like a taste bud on a tongue.

When the sensor is submersed in a liquid, each bead’s coating reacts to one chemical, and together they yield a distinct pattern of colors. A cameralike device monitors the pattern electronically to identify the chemicals in the mixture.

The original version of this electronic tongue, which the researchers revealed in 1998, used five different fluorescent coatings and therefore could discern only a lim ited range of tastes. Anslyn says new versions of the device have a lO-by-lO array of beads that can carry any of dozens of different coatings, enabling the device to ana lyze more complex mixtures of chemicals.

Anslyn envisions use of the electronic tongue in operations ranging from quality control of food processing to quick, in-office medical diagnostic tests, such as blood and urine analyses. The electronic tongue’s adaptability is limited only by the types of coatings used on the beads, Anslyn says. —SR

 

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Table of Contents

Week of Feb. 19, 2000; Vol. 157, No. 8

This Week's Cover

Make Way for the New Nose

A dog's ability to detect odors is legendary, but researchers are now developing devices that rival Fido's nose. New electronic noses can identify spoiled food, help diagnose medical conditions, and sniff out land mines. (Photo: John A. Rizzo/PhotoDisc)


Two Meningitis Bacteria Yield Genomes

Scientists have sequenced all the genes of two strains of a bacterium that causes meningitis, which may lead to the development of a much-needed vaccine.

Migration may reawaken Lyme disease

Lyme disease can hide in healthy-looking birds until the stress of migration drives it into a potentially infectious state.

Nuclei melt to make seething Big Bang soup

The seething primordial matter that existed in the first microseconds after the Big Bang may have briefly reappeared in fireballs created at a European particle accelerator.

Fly naps inspire dreams of sleep genetics

Researchers have discovered a sleep-like state in the fruit fly.

Tryst in space: Craft, asteroid rendezvous

On Valentine's Day, the NEAR spacecraft cozied up to the asteroid 433 Eros, becoming the first craft to orbit a tiny body.

Volcanoes aren't a big source of CFCs

Ozone-depleting chlorofluorocarbons in the atmosphere come mainly from human-made sources, not from volcanoes as some have suggested.

Testosterone shows hurtful, helpful sides

A small but significant portion of men taking large doses of testosterone experience mania, although moderate doses of the male sex hormone show promise in boosting the mood and sex drive of HIV-infected men.

Pancreatic enzymes may play role in shock

Pancreatic enzymes used for digestion may cause shock when they leach out of the small intestine and form a substance that activates white blood cells.


Hunting for Higher Dimensions

Experimenters scurry to test new theories suggesting that extra dimensions are detectable.

Eau, Brother!

Electronic noses provide a new sense of the future.


A possible signal from Polar Lander

Astronomers may have heard a faint signal from the vanished Mars Polar Lander spacecraft last month but, as of mid-February, have not detected another.

A chance to point Hubble

Get out your heavenly wish list: Astronomers working with the Hubble Space Telescope are soliciting suggestions for where to point the orbiting observatory this summer.

Protein may help the eyes tell time

A human version of melanopsin, originally found in the skin, eyes, and brains of frogs, has been discovered in the inner retina and may be the long-sought photoreceptor for the human biological clock.

Nogo makes cord regrowth a no go

Researchers have identified the gene for a protein that inhibits the regrowth of nerves in the spinal cord.

Glowing bacteria gobble gook in soil

A genetically engineered bacterium lights up as it breaks down organic contaminants in soil.

Don't eat the pepper-flavored paint

A derivative of the spicy chemical in chili peppers could find its way into a variety of products, including veterinary sutures and fiber optic cables.

 

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