Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

’Dog-on-a-chip’ could replace drug-sniffing canines

30.10.2003


Police dogs across the country could soon be out of work, replaced by an electronic "dog-on-a-chip" that sniffs out cocaine and other narcotics. Scientists at Georgia Tech have created a new detection tool that is portable, inexpensive, and doesn’t require feeding or grooming. They say it is superior to previous "electronic noses" designed for this purpose.



The report will appear in the Nov. 15 edition of Analytical Chemistry, a peer-reviewed journal of the American Chemical Society, the world’s largest scientific society.

"Our technology provides a hand-held sensing device capable of real-time detection, reducing the time between drug seizure and laboratory analysis," says Desmond Stubbs, a doctoral candidate in chemistry working under the direction of William Hunt, Ph.D., a professor of electrical engineering at Georgia Tech in Atlanta.


The sensor, which performed well in the lab and in a field test with the Georgia Bureau of Investigation, is "an elegant fusion of biotechnology and microelectronics," according to Hunt. This combination of disciplines makes the sensor superior to previous "electronic noses." The U.S. government will spend more than $19 billion this year in the war on drugs, according to the Office of National Drug Policy. Police dogs are important tools in this battle; their highly developed olfactory systems can detect small molecules in the part-per-billion range.

But using dogs has its drawbacks. They require expensive handlers to train and care for them, and the seized drugs must still be sent to the lab for further analysis — adding trained technicians and costly lab equipment to the tab.

Plus, scientists still don’t know exactly what chemicals the dogs are sensing, allowing for significant variations from one dog to the next. Dogs also have trouble detecting specific drug targets in the presence of other odors, such as coffee grounds. "Unfortunately, the illicit drug traffickers are aware of this and invariably mask their product with different chemicals to evade authorities," Stubbs says.

The new device addresses all of these issues.

Two key features of any vapor-sensing tool are sensitivity and specificity. Sensitivity is the ability to detect very small amounts of a chemical. Specificity is the ability to differentiate a certain chemical from a group of many similar ones (e.g., cocaine from coffee grounds).

The dog-on-a-chip can sense cocaine at a few trillionths of a gram. This sensitivity is achieved through surface acoustic wave (SAW) electronics, a method of detecting a chemical by measuring the disturbance it causes in sound waves across a tiny quartz crystal. This is a fairly common analytical method, and it has been used in other electronic noses, but by itself it does not address the problem of specificity.

The new chip goes a step further by incorporating monoclonal antibodies — cloned copies of proteins called antibodies that the immune system produces to fight foreign invaders. The researchers used anti-benzoylecgonine (anti-BZE) in the device because it differs only slightly in structure from cocaine, allowing it to bind preferentially to that molecule.

The SAW sensor is coated with a thin layer of anti-BZE. When a vapor sample passes through, cocaine molecules attach to anti-BZE molecules, causing a disturbance in the sound waves on the quartz crystal that is detected as an electrical signal.

"We are the first group to use specific antibodies to differentiate similar sized molecules in a complex vapor sample," Hunt says. This gives the dog-on-a-chip an advantage over its canine competitors and other electronic devices. It will also be significantly cheaper and less time-consuming by removing many of the steps from the current detection protocol.

The new device was carefully calibrated in a laboratory setting, and then it was put to the test in the field. "In field tests conducted at the Georgia Bureau of Investigation, we were able to detect cocaine obtained during an actual drug seizure," Stubbs says. "By simply drawing the vapor through our prototype device, we got a positive detection in a matter of seconds."

The ability to detect and identify small, non-volatile molecules like cocaine based on their electronic vapor signature could also be used in airports and other locations to detect explosives and chemical warfare agents, according to the researchers.

The U.S. Customs Service and the Office of National Drug Control Policy (ONDCP) provided funding for this research.

Michael Bernstein | EurekAlert!
Further information:
http://www.acs.org/

More articles from Process Engineering:

nachricht New technology for ultra-smooth polymer films
28.06.2018 | Fraunhofer-Institut für Organische Elektronik, Elektronenstrahl- und Plasmatechnik FEP

nachricht Diamond watch components
18.06.2018 | Schweizerischer Nationalfonds SNF

All articles from Process Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Global study of world's beaches shows threat to protected areas

19.07.2018 | Earth Sciences

New creepy, crawly search and rescue robot developed at Ben-Gurion U

19.07.2018 | Power and Electrical Engineering

Metal too 'gummy' to cut? Draw on it with a Sharpie or glue stick, science says

19.07.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>