Nanotubes gain touch and taste
DNA coating creates tiny, highly sensitive sensors
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Print 09.16.2005 @06:51 PM
Contributed by Simon
Edited by Simon
Researchers have given carbon nanotubes the ability to detect odors and tastes.
The trick, according to scientists at the University of Pennsylvania and Monell Chemical Sciences Center, is coating nanoscale carbon tubes with strands of DNA.
The researchers say that arrays of the nanosensors could detect molecules on the order of one part per million.
A news release describes the work:
In the report, the researchers tested the nanosensors on five different chemical odorants, including methanol and dinitrotoluene, or DNT, a common chemical that is also frequently a component of military-grade explosives. The nanosensors could sniff molecules out of the air or taste them in a liquid, suggesting applications ranging from domestic security to medical detectors.
"What we have here is a hybrid of two molecules that are extremely sensitive to outside signals: single stranded DNA, which serves as the 'detector,' and a carbon nanotube, which functions as 'transmitter,'" said A. T. Charlie Johnson, associate professor in Penn's Department of Physics and Astronomy. "Put the two together and they become an extremely versatile type of sensor, capable of finding tiny amounts of a specific molecule."
Given the size of such sensors each carbon nanotube is about a billionth of a meter wide, Johnson and his colleagues believe arrays of these sensors could serve as passive detection systems in almost any location. The sensor surface is also self-regenerating, with each sensor lasting for more than 50 exposures to the targeted substances, which means they would not need to be replaced frequently.
The biomolecules used to make the sensors can reportedly be engineered in a process called directed evolution to recognize a wide variety of targets.
"There are few limits as to what we could build these sensors to detect, whether it is a molecule wafting off an explosive device or the protein byproduct of a cancerous growth," says Johnson.
Anyone remember the Vietnam era "people sniffers" on helicopters?