Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Sniffer Dog on a Chip

15.09.2010
Highly sensitive TNT detection with nanowires

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), http://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: http://dx.doi.org/10.1002/anie.201000847

Fernando Patolsky | Angewandte Chemie
Further information:
http://www.tau.ac.il/chemistry/patolsky/
http://dx.doi.org/10.1002/anie.201000847
http://pressroom.angewandte.org

More articles from Life Sciences:

nachricht Biofuel produced by microalgae
28.02.2017 | Tokyo Institute of Technology

nachricht Decoding the genome's cryptic language
27.02.2017 | University of California - San Diego

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Safe glide at total engine failure with ELA-inside

On January 15, 2009, Chesley B. Sullenberger was celebrated world-wide: after the two engines had failed due to bird strike, he and his flight crew succeeded after a glide flight with an Airbus A320 in ditching on the Hudson River. All 155 people on board were saved.

On January 15, 2009, Chesley B. Sullenberger was celebrated world-wide: after the two engines had failed due to bird strike, he and his flight crew succeeded...

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Scientists reach back in time to discover some of the most power-packed galaxies

28.02.2017 | Physics and Astronomy

Nano 'sandwich' offers unique properties

28.02.2017 | Materials Sciences

Light beam replaces blood test during heart surgery

28.02.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>