Made up of a silicon microcantilever bearing nearly 500,000 aligned titanium dioxide nanotubes, this device can detect concentrations of trinitrotoluene (TNT) of around 800 ppq (i.e. 800 molecules of explosive per 1015 molecules of air), improving one thousand-fold the detection limit attainable until now.
This innovative concept could also be used to detect drugs, toxic agents and traces of organic pollutants. This work is published on 29 May 2012 in the journal Angewandte Chemie.
The efficient detection of explosives such as trinitrotoluene (TNT) represents a difficult challenge in terms of security. Indeed, these compounds have very low volatility and it takes extremely sensitive sensors to detect them at a distance. Current systems detect concentrations of around 1 ppb (one molecule per 109 molecules of air), but this level of performance can be insufficient to ensure airport security for example. Yet, numerous animals have a sense of smell that can go well below this limit including, for example, the silkmoth (Bombyx mori), capable of reacting to the capture of just a few pheromone molecules. Its antennas are composed of strands of around one millimeter in length, bearing a large of number of sensilla, micrometric sized organs directly connected to the sensory neurons. It is this structure that the researchers sought to imitate.
The system that they have developed comprises a 200-micron long and 30-micron wide silicon microcantilever. This support has been nanostructured with around 500,000 vertically aligned titanium dioxide nanotubes. The role of these nanostructures is to multiply the surface area of the microcantilever by a factor of around one hundred and to proportionally increase the chances of capturing the molecules being searched for. By making the microcantilever vibrate, it is possible to determine whether the ambient air contains traces of TNT and if these molecules have been captured by the device. In fact, the microcantilever has a particular resonance frequency that is modified in a specific manner when it absorbs molecules of explosive.
To test the performance of this device, the researchers released very small quantities of TNT in a controlled manner. In this way, there were able to establish that the sensitivity of the device was 800 ppq (800 molecules per million billion molecules (1015)). No current device is able to detect such low concentrations of explosives. These performance levels are similar to those of trained sniffer dogs.
Research and development work is still necessary before an easy-to-use device based on these nanostructured levers can be obtained. One of the next steps is to design a device capable of specifically recognizing the type of explosive absorbed. The scientists already hope to adapt these microcantilevers to the detection of other explosives, such as pentrite, which could pose security problems in Europe. Furthermore, this method could also be used to detect various drugs which, like explosives, have very low volatility. In environmental terms, this bio-inspired device could make it possible to measure infinitesimal traces of pollutants such as volatile organic compounds, which have become a major health issue.
Bio-Inspired Nanostructured Sensor for the Detection of Ultralow Concentrations of Explosives. D. Spitzer, T. Cottineau, N. Piazzon, S. Josset, F. Schnell, S. N. Pronkin, E. R. Savinova, and V. Keller. Angewandte Chemie. 29 May 2012.
Contact informationResearchers l Denis Spitzer l T +33 (0)3 89 69 50 75 l firstname.lastname@example.org
One step closer to reality
20.04.2018 | Max-Planck-Institut für Entwicklungsbiologie
The dark side of cichlid fish: from cannibal to caregiver
20.04.2018 | Veterinärmedizinische Universität Wien
University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.
Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.
Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.
Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...
Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.
The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...
Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.
Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...
In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...
13.04.2018 | Event News
12.04.2018 | Event News
09.04.2018 | Event News
20.04.2018 | Physics and Astronomy
20.04.2018 | Interdisciplinary Research
20.04.2018 | Physics and Astronomy