Chemical Nanosensors/IED detectors

We believe that the employment of new nanomaterials, dual electro-optical transduction and cost effective fabrication methods allow the development of novel chemosensors/ sensor arrays for precise and reliable detection of small molecule gases. Dual transduction, heterogeneous integration of a transducer and analyzing elements with sensory nanomaterial can significantly improve the device's performance: dramatically increase sensitivity and selectivity, reduce response and recovery time, make it robust and cost effective. In particular, we are now working on the development of nanocomposite optical chemosensors for explosives detection, where one-dimensional nanoporous photonic crystal is infiltrated with fluorescent sensory polymers.3a, 4a, 10a, 1b, 2b

Images of the prototypes for explosive detection Mark-I (left) and Mark-II (right).

The capabilities and potential of our first portable prototype (Mark-I) for explosive detection were successfully demonstrated in 2008 year at Army facilities. Later, in 2009, the second improved prototype (Mark-II) was demonstrated to the Army representatives at Emitech' laboratory. Mark-II prototype is capable to detect RDX/PETN/TNT vapors and particulates in real time mode using our proprietary sampling system based on air-jet technique. PETN is a lethal agent used by a great number of terrorist organizations in recent years. Most recently, it was found in a much  publicized attack in packages sent from Yemen in October 2010. It was used on Christmas Day in 2009, when an airline passenger made a bombing attempt in a device strapped to the leg of the terrorist. It was also used in an assassination attempt on the country's counterterrorism operations chief in August, 2009, as well as by the convicted "Shoe bomber", Richard Reed. Another feature of Mark-II prototype is the sensor mounting on the robotic vehicle and wireless communication with remote terminal. Both prototypes demonstrate much better selectivity to nitroaromatic interferants than commercially available portable detector for explosives5b.

The video shows detection of RDX with surface concentration of 2 µg per cm2 by our Mark-II prototype equipped with Emitech's proprietary sampling system, which allows to detect RDX in real time mode avoiding swabbing and any contact with inspected surface (RDX/PETN real time detection without swabbing is not possible for commercially available explosive detectors).

Another direction is related to the prototyping of the resistive gas sensors based on point heterocontact between carbon nanotubes and metal wires. In collaboration with a Ukrainian team (Inst.Low Temp.Phys., Kharkov), we proposed to develop sensors for noninvasive human breath analysis and a decease diagnostic. This is a good example, as the combination of a fundamental scientific concept (point contact spectroscopy) with nanoscaled structures provides a novel sensing platform and advanced sensory devices with extremely high sensitivity, good selectivity and fast response/recovery time. These gas sensors are principally distinctive from any existing resistive chemosensors employing sensory films or nanomaterials due to their nano/angstrom conductive channel leading to superior sensing characteristics.