By Cyrille Cartier

WASHINGTON, Nov 21 (Reuters) - A new device called a "dog on a chip" may combine the benefits of technology and nature by not only detecting dangerous or illicit substances but by providing the electronic equivalent of a dog barking, researchers said on Friday.

The device is more accurate and faster than other electronic sensors and drug-sniffing dogs, a team at the Georgia Institute of Technology said.

"We took the road less traveled and went in the direction of fusing biotechnology and microelectronics," said William Hunt, a professor of electrical and computer engineering who led the study.

The dog-on-a-chip works with antibodies by looking at their molecular structure, Hunt said. In this case the researchers tested cocaine antibodies, which change in structure and mass if they come into contact with cocaine molecules.

On the device, these changes trigger an electronic alert through a laptop, Hunt said, but researchers hope to make the whole package portable and battery-operated, either as a hand-held unit or as a device monitoring a particular area.

Unlike this new device, most electronic noses require an air sample that is transformed into a liquid before being analyzed for illegal drugs, explosives or chemicals, Hunt said.

One of the greatest attributes of the penny-sized electronic nose is that it will be on a constant lookout, said molecular biologist John Cairney at Atlanta's Institute of Paper Science & Technology.

"It's a matter of sampling," Cairney said in a telephone interview. "You can't sit a dog in a warehouse 24/7. You can't sit a dog in a sewer or water pipe 24/7, or in an air conditioning unit in a public building."

DOG SUPPORTERS

But the low-tech dog approach still has its supporters.

The U.S. Customs Service, which partially funded the project, also trains dogs to look for drugs, money and smuggled people.

The dog program is cost-effective, said Lee Titus, director of the dog training program in Virginia. In 2002, the narcotics teams of dogs and their handlers that cost about $60,000 per year, found nearly $600,000 worth of drugs.

A dog can go through about 500 packages in a mailroom in a few minutes, Titus said. "How long would it take you to go through and check each little package with a machine?" Titus asked

"I think that a well-trained dog is more versatile than a piece of machinery."

The Georgia Bureau of Investigation provided the cocaine and laboratory where the electronic nose successfully identified the presence of cocaine 6 inches (15 cm) away, Hunt said.

The Office of National Drug Control Policy and the U.S. Customs Service, which is part of the Homeland Security Department, provided funding for the project. The research was reported in the November issue of the journal of the American Chemical Society.