Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Sniffer Dog on a Chip

Dog on a chip: Explosives can be detected with unprecedented sensitivity by using arrays of silicon nanowire field-effect transistors modified with an electron-rich aminosilane monolayer, which form complexes with the analytes (see picture). These “nanosniffers” can be used to sense the presence of TNT at concentrations as low as 1×10−6 ppt, which is superior to that of sniffer dogs or any other known explosive detection method.
Dog on a chip: Explosives can be detected with unprecedented sensitivity by using arrays of silicon nanowire field-effect transistors modified with an electron-rich aminosilane monolayer, which form complexes with the analytes (see picture). These “nanosniffers” can be used to sense the presence of TNT at concentrations as low as 1×10−6 ppt, which is superior to that of sniffer dogs or any other known explosive detection method.

Abstract:
Highly sensitive TNT detection with nanowires

Sniffer Dog on a Chip

Weinheim, Germany | Posted on September 15th, 2010

To thwart possible terrorist attacks and to detect contamination on sites of former military installations, researchers have been concentrating their efforts in recent years on methods for the detection and analysis of explosives. Fernando Patolsky and his team at the University of Tel Aviv have now developed a novel sensor chip that detects trinitrotoluene (TNT), as well as other explosive species, with high sensitivity and without a concentration step. As the Israeli researchers report in the journal Angewandte Chemie, their detector is superior to sniffer dogs and all other previous detection methods for this explosive.

The difficulty with the detection of explosives such as TNT is their extremely low volatility. Methods available for the analysis of air samples are expensive and time-consuming, and require large, bulky instruments, laborious sample preparation, and expert handling. "There is a need for an inexpensive, miniaturizable method that allows for quick, easy, and robust high-throughput analysis in the field," says Patolsky.

The scientists built their sensor using the principle of a nanoscale field-effect transistor. In contrast to a current-controlled classical transistor, a field-effect transistor is switched by means of an electric field. At the core of the device are nanowires made of the semiconductor silicon. These were coated with a molecular layer made from special silicon compounds that contains amino groups (NH2). TNT molecules bind to these amino groups in the form of charge-transfer complexes. The binding process involves the transfer of electrons from the electron-rich amino groups to the electron-poor TNT. This change in the charge distribution on the surface of the nanowires modulates the electric field and leads to an abrupt change in the conductivity of the nanowires, which is easily measured.

To improve the signal-to-noise ratio and thus increase the sensitivity, the scientists equipped their chip with an array of about 200 individual sensors. "We are thus able to analyze liquid and gaseous samples without prior concentration or other sample preparation at previously unattainable sensitivities," says Patolsky. "We were able to analyze concentrations down to 0.1 ppt (parts per trillion); that is, one molecule of TNT in 10 quadrillion other molecules." The sensor can be quickly regenerated by washing and is selective for TNT; other related molecules do not react the same way.

"We are now creating a chip based on large arrays of nanosensors chemically modified with a large number of chemical receptors, with different binding capabilities, in order to detect a whole spectrum of explosive species in parallel," says Patolsky.

Author: Fernando Patolsky, Tel Aviv University (Israel), www.tau.ac.il/chemistry/patolsky/

Title: Supersensitive Detection of Explosives by Silicon Nanowire Arrays

Angewandte Chemie International Edition 2010, 49, No. 38, 6830-6835, Permalink to the article: dx.doi.org/10.1002/anie.201000847

####

For more information, please click here

Contacts:

Copyright © Angewandte Chemie

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Forces of nature: Interview with microscopy innovators Gerd Binnig and Christoph Gerber August 26th, 2016

A promising route to the scalable production of highly crystalline graphene films August 26th, 2016

Graphene under pressure August 26th, 2016

New electrical energy storage material shows its power: Nanomaterial combines attributes of both batteries and supercapacitors August 25th, 2016

Possible Futures

A promising route to the scalable production of highly crystalline graphene films August 26th, 2016

Graphene under pressure August 26th, 2016

Johns Hopkins scientists track metabolic pathways to find drug combination for pancreatic cancer August 25th, 2016

New electrical energy storage material shows its power: Nanomaterial combines attributes of both batteries and supercapacitors August 25th, 2016

Sensors

A promising route to the scalable production of highly crystalline graphene films August 26th, 2016

Down to the wire: ONR researchers and new bacteria August 18th, 2016

'Sniffer plasmons' could detect explosives: Scientists have proposed a graphene-based spaser that can detect even small amounts of various substances, including explosives August 16th, 2016

Perpetual 'ice water': Stable solid-liquid state revealed in nanoparticles: Gallium nanoparticles that are both solid and liquid are stable over a range of 1000 degrees Fahrenheit August 5th, 2016

Announcements

Forces of nature: Interview with microscopy innovators Gerd Binnig and Christoph Gerber August 26th, 2016

A promising route to the scalable production of highly crystalline graphene films August 26th, 2016

Graphene under pressure August 26th, 2016

Nanofiber scaffolds demonstrate new features in the behavior of stem and cancer cells August 25th, 2016

Homeland Security

Down to the wire: ONR researchers and new bacteria August 18th, 2016

Hexagonal boron nitride semiconductors enable cost-effective detection of neutron signals: Texas Tech University researchers demonstrate hexagonal boron nitride semiconductors as a cost-effective alternative for inspecting overseas cargo containers entering US ports August 17th, 2016

'Sniffer plasmons' could detect explosives: Scientists have proposed a graphene-based spaser that can detect even small amounts of various substances, including explosives August 16th, 2016

'Second skin' protects soldiers from biological and chemical agents August 5th, 2016

Military

New electrical energy storage material shows its power: Nanomaterial combines attributes of both batteries and supercapacitors August 25th, 2016

Nanoparticles that speed blood clotting may someday save lives August 23rd, 2016

Curbing the life-long effects of traumatic brain injury August 19th, 2016

Lab team spins ginger into nanoparticles to heal inflammatory bowel disease August 19th, 2016

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







Car Brands
Buy website traffic