Nano-based Chip Detects Explosives

Technical University of Denmark (DTU) is ready with a prototype for a chemical “sniffer system” for the detection of criminal substances like narcotics and explosivesDogs have an eminent sense of smell. Their snouts use a specific sniffing technique which almost grabs hold of scents. Elephants’ snouts are even better than those of dogs, but obviously these are attached to elephants which are difficult to carry around. Consequently, today dogs are employed to track narcotics, money and explosives. Sometimes dogs are able to sense explosives in very small doses, however, they are not always 100 percent reliable as they are also sensitive to changes in their surroundings. A technological solution is therefore to be preferred in the tracking of stocks of narcotics or explosive materials.

Researchers at DTU have developed the prototype of a chip able to sniff molecular structures from a number of known substances. A special camera visualises the results from the chip (with 24 megapixels per 15 second) and newly developed software interprets these images according to changes in colour (i.e. the difference between two pictures), caused by the impact of the scents in the air.

We have conducted experiments by sucking air from smaller containers like e.g. handbags or pieces of luggage and from large industrial sized containers typically used for smuggling. In both cases, we arrived at promising results”, says Mogens Havsteen Jakobsen, Senior Researcher at DTU Nanotech.

By using the so-called colorimetric sensing technique, the artificial nose is able to detect different substances like explosives, narcotics, the ripeness of cheese, rotten meat and fish, the quality of wine and coffee or bad indoor climate of a room.

The project has specifically targeted explosives which are a growing safety risk in our society. The Chemical Division of the Danish Emergency Management Agency has been an important collaborator because they are authorised to produce and handle explosives. “We have test laboratories which have been made available during the course of the project”, says Jesper Mogensen, civil engineer and analysis chemist at the Chemical Division and therefore used to handling explosives.

There will be some evident advantages in using a technology such as CRIM-TRACK, compared to the instruments available today,” Jesper Mogensen says. “Firstly, the preparation time is short in that what you largely need to do is switch on the tracker and use it. This is valuable time saved. Secondly and perhaps the most important advantage is the fact that the EOD (the Explosive Ordnance Disposal) does not need to collect a sample. Today when we are called to a ransacking if e.g. a kilo of white powder has been found and we have to analyse its chemistry by way of GC-MS (i.e. gas chromatography-mass spectrometry), a sample of the substance must be collected on a fibre. In other words, it is necessary to collect physically a sample with all the risks this entails. With DTU’s sniffer system, it is possible to collect samples in the air. It sniffs for the drug much like a dog and indicates whether there are any explosives or not. This will increase the safety of our EOD”.


How To Turn Plants Into Bomb-Sniffing Machines

Spinach is no longer just a superfood: By embedding leaves with carbon nanotubes, MIT engineers have transformed spinach plants into sensors that can detect explosives and wirelessly relay that information to a handheld device similar to a smartphone. This is one of the first demonstrations of engineering electronic systems into plants, an approach that the researchers call “plant nanobionics”.


The goal of plant nanobionics is to introduce nanoparticles into the plant to give it non-native functions,” says Michael Strano, the Carbon P. Dubbs Professor of Chemical Engineering at MIT and the leader of the research team.

In this case, the plants were designed to detect chemical compounds known as nitroaromatics, which are often used in landmines and other explosives. When one of these chemicals is present in the groundwater sampled naturally by the plant, carbon nanotubes embedded in the plant leaves emit a fluorescent signal that can be read with an infrared camera. The camera can be attached to a small computer similar to a smartphone, which then sends an email to the user.

This is a novel demonstration of how we have overcome the plant/human communication barrier,” says Strano, who believes plant power could also be harnessed to warn of pollutants and environmental conditions such as drought.

Strano is the senior author of a paper describing the nanobionic plants in  Nature Materials. The paper’s lead authors are Min Hao Wong, an MIT graduate student who has started a company called Plantea to further develop this technology, and Juan Pablo Giraldo, a former MIT postdoc who is now an assistant professor at the University of California at Riverside.

Michael McAlpine, an associate professor of mechanical engineering at the University of Minnesota, says this approach holds great potential for engineering not only sensors but many other kinds of bionic plants that might receive radio signals or change color. “When you have manmade materials infiltrated into a living organism, you can have plants do things that plants don’t ordinarily do,” says McAlpine, who was not involved in the research. “Once you start to think of living organisms like plants as biomaterials that can be combined with electronic materials, this is all possible.”

In the 2014 plant nanobionics study, Strano’s lab worked with a common laboratory plant known as Arabidopsis thaliana. However, the researchers wanted to use common spinach plants for the latest study, to demonstrate the versatility of this technique. “You can apply these techniques with any living plant,” Strano says. So far, the researchers have also engineered spinach plants that can detect dopamine, which influences plant root growth, and they are now working on additional sensors, including some that track the chemicals plants use to convey information within their own tissues. “Plants are very environmentally responsive,” Strano says. “They know that there is going to be a drought long before we do. They can detect small changes in the properties of soil and water potential. If we tap into those chemical signaling pathways, there is a wealth of information to access.”

These sensors could also help botanists learn more about the inner workings of plants, monitor plant health, and maximize the yield of rare compounds synthesized by plants such as the Madagascar periwinkle, which produces drugs used to treat cancer. “These sensors give real-time information from the plant. It is almost like having the plant talk to us about the environment they are in,” Wong says. “In the case of precision agriculture, having such information can directly affect yield and margins.”


Sniffing Out Explosives, Better Than Trained Dogs

Tel Aviv University researchers have built a groundbreaking sensor that detects miniscule concentrations of hazardous materials in the air. Security forces worldwide rely on sophisticated equipment, trained personnel, and detection dogs to safeguard airports and other public areas against terrorist attacks. A revolutionary new electronic chip with nano-sized chemical sensors is about to make their job much easier. The groundbreaking nanotechnology-inspired sensor, devised by Prof. Fernando Patolsky of Tel Aviv University‘s School of Chemistry and Center for Nanoscience and Nanotechnology, and developed by the Herzliya company Tracense, picks up the scent of explosives molecules better than a detection dog’s nose.
Existing explosives sensors are expensive, bulky and require expert interpretation of the findings. In contrast, the new sensor is mobile, inexpensive, and identifies in real time — and with great accuracy explosives in the air at concentrations as low as a few molecules per 1,000 trillion.
explosive detective dog
Using a single tiny chip that consists of hundreds of supersensitive sensors, we can detect ultra low traces of extremely volatile explosives in air samples, and clearly fingerprint and differentiate them from other non-hazardous materials,” said Prof. Patolsky, a top researcher in the field of nanotechnology. “In real time, it detects small molecular species in air down to concentrations of parts-per-quadrillion, which is four to five orders of magnitude more sensitive than any existing technological method, and two to three orders of magnitude more sensitive than a dog’s nose. “This chip can also detect improvised explosives, such as TATP (triacetone triperoxide), used in suicide bombing attacks in Israel and abroad,” Prof. Patolsky added.
Research on the sensor was recently published in the journal Nature Communications.


Detection device 1000 times more powerfull

Imitating the antennas of the silkmoth to design a system for detecting explosives with unparalleled performance. Made up of a silicon microcantilever bearing nearly 500,000 aligned titanium dioxide nanotubes, this device is capable of detecting concentrations of trinitrotoluene (TNT) of around 800 ppq (1) (i.e. 800 molecules of explosive per 10^15 molecules of air), thereby 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 was published on May 29 2012 in the journal Angewandte Chemie.


Research and development work is still necessary before an easy-to-use device based on these  nanostructured levers can be obtained. Let's remind that earlier this year a team from Nederlands used the Cricket to build nanostructured  ultra sensitive antennas.
Research is led  by a team from the "Nanomatériaux pour Systèmes sous Sollicitations Extrêmes" unit (CNRS / Institut Franco-Allemand de Recherches de Saint-Louis), in collaboration with the Laboratoire des Matériaux, Surfaces et Procédés pour la Catalyse (CNRS / Université de Strasbourg), FRANCE.