Design and manufacture of TNT explosives detector sensors based on CNTFET

Sensor Review ◽  
2016 ◽  
Vol 36 (4) ◽  
pp. 414-420 ◽  
Author(s):  
Saeid Masoumi ◽  
Hassan Hajghassem ◽  
Alireza Erfanian ◽  
Ahmad Molaei Rad

Purpose Miniaturized smart sensors that can perform sensitive and selective real-time monitoring of target analytes are tremendously valuable for various sensing applications. So, the purpose of this paper is to provide details of sensors based on selective nanocoatings by combining trinitrotoluene (TNT) receptors bound to conjugated polydiacetylene (PDA) polymers with single-walled carbon nanotube field-effect transistors (CNTFETs) for detecting explosives TNT. Design/methodology/approach Following an introduction, this paper describes the way of creating an FET with CNTs, which are functionalized by the peptide based on TNT molecule recognition elements and PDA, to offer a system which has the capability of answering the presence of related target molecules (TNT). Finally, brief conclusions are drawn. Findings Single-wall nanotubes and reduced graphene oxide are interesting materials for creating biosensors of FETs at nanoscale because of unique electrical, mechanical, geometrical and biocompatible properties. Therefore, this sensor is designed and manufactured, and the results of applying TNT to sensor show good sensitivity and selectivity response. Originality/value In this timeframe of history, sensors based on CNTFET are required for different uses, including clinical diagnosis technologies, environmental tests and bioterrorism recognition technologies, that correspond to the military conflicts and terrorism. So, CNTFET sensor design provides real-time detection of TNT explosives.

Sensor Review ◽  
2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Haowei Zhang ◽  
Lili Sun ◽  
Chengli Song ◽  
Ying Liu ◽  
Xueting Xuan ◽  
...  

Purpose Design, fabricate and evaluate all-solid-state wearable sensor systems that can monitor ion concentrations in human sweat to provide real time health analysis and disease diagnosis capabilities. Design/methodology/approach A human health monitoring system includes disposable customized flexible electrode array and a compact signal transmission-processing electronic unit. Findings Patterned rGO (reduced-graphene oxide) layers can replace traditional metal electrodes for the fabrication of free-standing all solid film sensors to provide improved flexibility, sensitivity, selectivity, and stability in ion concentration monitoring. Electrochemical measurements show the open circuit potential of current selective electrodes exhibit near Nernst responses versus Na+ and K+ ion concentration in sweat. These signals show great stability during a typical measurement period of 3 weeks. Sensor performances evaluated through real time measurements on human subjects show strong correlations between subject activity and sweating levels, confirming high degree of robustness, sensitivity, reliability and practicality of current sensor systems. Originality/value In improving flexibility, stability and interfacial coherency of chemical sensor arrays, rGO films have been the developed as a high-performance alternative to conventional electrode with significant cost and processing complexity reduction. rGO supported solid state electrode arrays have been found to have linear potential response versus ion concentration, suitable for electrochemical sensing applications. Current sweat sensor system has a high degree of integration, including electrode arrays, signal processing circuits, and data visualization interfaces.


2021 ◽  
Vol 11 (23) ◽  
pp. 11368
Author(s):  
Irina Valitova ◽  
Alexandria Mitchell ◽  
Michael A. Hupman ◽  
Ian G. Hill ◽  
Alasdair Syme

Interest in the use of organic electronic devices in radiation sensing applications has grown in recent years. The numerous device configurations (e.g., diodes, thin film transistors) and potential for improved tissue equivalence compared to their silicon-based analogues make them attractive candidates for various radiation dosimetry measurements. In this work, a variation of the organic thin film transistor (OTFT) is studied, in which a polymer electret is added. An OTFT electret design can be used in either a wired or wireless configuration for in vivo dosimetry with the possibility of real-time detection. The linearity, reproducibility, and dependence on energy of these devices were measured through exposure to 100 kVp photons from an orthovoltage treatment unit (Xstrahl 300) and 6 MV photons from a Varian TrueBeam medical linear accelerator. Prior to irradiation, all transistors were programmed with a −80 V bias applied to the Gate electrode (Vg) for 3 s. In the wireless configuration, after each delivered dose, the transfer characteristic was scanned to readout the amount of erased charges by monitoring the drain current change. When the programmed charge was sufficiently depleted by radiation, transistors were reprogrammed for repeated use. The real-time readout in a wired configuration was performed by measuring the drain current with Vg = −15 V; Vd = −15 V. The 6 MV photon beam was turned on and off at different dose rates of 600, 400, 300, 200, and 60 cGy/min to quantify the sensitivity of the device to changes in dose rate. The wireless transistors showed a linear increase in current with increasing dose. The sensitivities for different energies were 60 ± 5 nA/Gy at 6 MV at a dose rate of 600 cGy/min and 80 ± 10 nA/Gy at 100 kVp at a dose rate of 200 cGy/min. The sensitivity of detectors tested in a wired configuration at Vd = −15 V; Vg = −15 V was 8.1 nA/s at a dose rate of 600 cGy/min. The principle of pentacene OTFTs with polymer electret as radiation detectors was demonstrated. Devices had excellent linearity, reproducibility, and were able to be reprogrammed for multiple uses as wireless detectors. The wired transistors demonstrated an effective response as real-time detectors.


RSC Advances ◽  
2015 ◽  
Vol 5 (20) ◽  
pp. 15728-15735 ◽  
Author(s):  
Joon-Hyung Jin ◽  
Junhyup Kim ◽  
Taejin Jeon ◽  
Su-Kyoung Shin ◽  
Jong-Ryeul Sohn ◽  
...  

A SWNT-FET directly functionalized with immunoglobulin M shows a wide detection range from sub-picomolar to micromolar with an excellent sensitivity due to chemical gating in selective monitoring of fungal allergens.


Sensor Review ◽  
2019 ◽  
Vol 39 (6) ◽  
pp. 819-827 ◽  
Author(s):  
Saeid Masoumi ◽  
Hassan Hajghassem

Purpose Smart biosensors that can perform sensitive and selective monitoring of target analytes are tremendously valuable for trinitrotoluene (TNT) explosive detection. In this research, the pre-developed sensor was integrated with biological receptors in which they enhanced the sensitivity of the sensor. This is due to conjugated polydiacetylene onto a peptide-based molecular recognition element (Trp-His-Trp) for TNT molecules in graphene field-effect transistors (GR-FETs) as biosensor that is capable of responding to the presence of a TNT target with a colorimetric response. The authors confirmed the efficacy of the receptor while being attached to polydiacetylene (PDA) by observing the binding ability between the Trp-His-Trp and TNT to alter the electronic band structure of the PDA conjugated backbones. The purpose of this paper is to demonstrate a modular system capable of transducing small-molecule TNT binding into a detectable signal. The details of the real-time and selective TNT biosensor have been reported. Design/methodology/approach Following an introduction, this paper describes the way of fabrication GR-FETs with conventional photolithography techniques and the other processes, which is functionalized by the TNT peptide receptors. The authors first determined the essential TNT recognition elements from UV-visible spectrophotometry spectroscopy for PDA sensor unit fabrication. In particular, the blue percentage and the chromic response were used to characterize the polymerization parameter of the conjugated p backbone. A continuous-flow trace vapor source of nitroaromatics (two, four, six-TNT) was designed and evaluated in terms of temperature dependence. The TNT concentration was measured by liquid/gas extraction in acetonitrile using bubbling sequence. The sensor test is performed using a four-point probe and semiconductor analyzer. Finally, brief conclusions are drawn. Findings Because of their unique optical and stimuli-response properties, the polydiacetylene and peptide-based platforms have been explored as an alternative to complex mechanical and electrical sensing systems. Therefore, the authors have used GR-FETs with biological receptor-PDAs as a biosensor for achieving high sensitivity and selectivity that can detect explosive substances such as TNT. The transport property changed compared to that of the field-effect transistors made by intrinsic graphene, that is, the Dirac point position moved from positive Vg to negative Vg, indicating the transition of graphene from p-type to n-type after annealing in TNT, and when the device was tested from RT, the response of the device was found to increase linearly with increasing concentrations. Average shifting rate of the Dirac peak was obtained as 0.1-0.3 V/ppm. The resulting sensors exhibited at the limit ppm sensitivity toward TNT in real-time, with excellent selectivity over various similar aromatic compounds. The biological receptor coating may be useful for the development of sensitive and selective micro and nanoelectronic sensor devices for various other target analytes. Originality/value The detection of illegally transported explosives has become important as the global rise in terrorism subsequent to the events of September 11, 2001, and is at the forefront of current analytical problems. It is essential that a detection method has the selectivity to distinguish among compounds in a mixture of explosives. So, the authors are reporting a potential solution with the designing and manufacturing of electrochemical biosensor using polydiacetylene conjugated with peptide receptors coated on GR-FETs with the colorimetric response for real-time detection of TNT explosives specifically.


2018 ◽  
Vol 90 (1) ◽  
pp. 202-209 ◽  
Author(s):  
Kamil Krasuski ◽  
Damian Wierzbicki ◽  
Henryk Jafernik

Purpose The purpose of this paper is to study the implementation of GNSS technique in aviation for recovery of aircraft’s position using Precise Point Positioning (PPP) method. Design/methodology/approach The aircraft’s coordinates in ellipsoidal frame were obtained based on GPS code and phase observations for PPP method. The numerical computations were executed in post-processing mode in the CSRS-PPP and magicPPP online services. The mathematical scheme of PPP method was development using indifference equations of Ionosphere-Free linear combination. In the experiment, airborne test using Cessna 172 aircraft on June 01, 2010 in the military airport in Deblin was realized. The aircraft’s position was determined using data from GNSS receiver (Topcon HiperPro with interval of 1 s). Findings In this paper, the accuracy of aircraft’s position is better than 0.07 m for CSRS-PPP service and better than 0.27 m for magicPPP service. In case of the Mean Radial Spherical Error parameter, the average value for CSRS-PPP service equals to 0.01 m, whereas for magicPPP, it is about 0.38 m. The values of vertical coordinate of Cessna 172 aircraft were also checked with results of Real Time Kinematic–On The Fly technique. Research limitations/implications In this paper, the analysis of aircraft positioning is focused on the application of the PPP method in post-processing mode. In near real time, the PPP method still has limitations, especially in the area of ambiguity resolution and also instrumental biases (e.g. Narrow Lane Hardware Delays). Practical implications The PPP method can be applied in aviation in post-processing mode for verification of true aircraft coordinates and elimination of blunder errors from adjustment processing of GNSS observations. The Zenith Wet Delay term as a product of troposphere delay and receiver clock bias as a product of precise time transfer can be obtained in the PPP method. Originality/value The paper presents that the PPP method is an alternative solution for the recovery of aircraft’s position in aviation, and this method can be also applied in the positioning of aircraft based on GLONASS or GPS/GLONASS data.


Sensor Review ◽  
2018 ◽  
Vol 38 (2) ◽  
pp. 181-193 ◽  
Author(s):  
Saeid Masoumi ◽  
Hassan Hajghassem ◽  
Alireza Erfanian ◽  
Ahmad Molaei Rad

Purpose Smart sensors based on graphene field effect transistor (GFET) and biological receptors are regarded as a promising nanomaterial that could be the basis for future generation of low-power, faster, selective real-time monitoring of target analytes and smaller electronics. So, the purpose of this paper is to provide details of sensors based on selective nanocoatings by combining trinitrotoluene (TNT) receptors (Trp-His-Trp) bound to conjugated polydiacetylene polymers on a graphene channel in GFET for detecting explosives TNT. Design/methodology/approach Following an introduction, this paper describes the way of manufacturing of the GFET sensor by using investigation methods for transferring graphene sheet from Cu foil to target substrates, which is functionalized by the TNT peptide receptors, to offer a system which has the capability of answering the presence of related target molecules (TNT). Finally, brief conclusions are drawn. Findings In a word, shortly after graphene discovery, it has been explored with a variety of methods gradually. Because of its exceptional electrical properties (e.g. extremely high carrier mobility and capacity), electrochemical properties such as high electron transfer rate and structural properties, graphene has already showed great potential and success in chemical and biological sensing fields. Therefore, the authors used a biological receptor with a field effect transistor (FET) based on graphene to fabricate sensor for achieving high sensitivity and selectivity that can detect explosive substances such as TNT. The transport property changed compared to that of the FET made by intrinsic graphene, that is, the Dirac point position moved from positive Vg to negative Vg, indicating the transition of graphene from p-type to n-type after annealing in TNT, and the results show the bipolar property change of GFET with the TNT concentration and the possibility to develop a robust, easy-to-use and low-cost TNT detection method for performing a sensitive, reliable and semi-quantitative detection in a wide detection range. Originality/value In this timeframe of history, TNT is a common explosive used in both military and industrial settings. Its convenient handling properties and explosive strength make it a common choice in military operations and bioterrorism. TNT and other conventional explosives are the mainstays of terrorist bombs and the anti-personnel mines that kill or injure more than 15,000 people annually in war-torn countries. In large, open-air environments, such as airports, train stations and minefields, concentrations of these explosives can be vanishingly small – a few parts of TNT, for instance, per trillion parts of air. That can make it impossible for conventional bomb and mine detectors to detect the explosives and save lives. So, in this paper, the authors report a potential solution with design and manufacture of a GFET sensor based on a biological receptor for real-time detection of TNT explosives specifically.


Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4425
Author(s):  
Ana María Pineda-Reyes ◽  
María R. Herrera-Rivera ◽  
Hugo Rojas-Chávez ◽  
Heriberto Cruz-Martínez ◽  
Dora I. Medina

Monitoring and detecting carbon monoxide (CO) are critical because this gas is toxic and harmful to the ecosystem. In this respect, designing high-performance gas sensors for CO detection is necessary. Zinc oxide-based materials are promising for use as CO sensors, owing to their good sensing response, electrical performance, cost-effectiveness, long-term stability, low power consumption, ease of manufacturing, chemical stability, and non-toxicity. Nevertheless, further progress in gas sensing requires improving the selectivity and sensitivity, and lowering the operating temperature. Recently, different strategies have been implemented to improve the sensitivity and selectivity of ZnO to CO, highlighting the doping of ZnO. Many studies concluded that doped ZnO demonstrates better sensing properties than those of undoped ZnO in detecting CO. Therefore, in this review, we analyze and discuss, in detail, the recent advances in doped ZnO for CO sensing applications. First, experimental studies on ZnO doped with transition metals, boron group elements, and alkaline earth metals as CO sensors are comprehensively reviewed. We then focused on analyzing theoretical and combined experimental–theoretical studies. Finally, we present the conclusions and some perspectives for future investigations in the context of advancements in CO sensing using doped ZnO, which include room-temperature gas sensing.


Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1922
Author(s):  
Gwang Su Kim ◽  
Yumin Park ◽  
Joonchul Shin ◽  
Young Geun Song ◽  
Chong-Yun Kang

The breath gas analysis through gas phase chemical analysis draws attention in terms of non-invasive and real time monitoring. The array-type sensors are one of the diagnostic methods with high sensitivity and selectivity towards the target gases. Herein, we presented a 2 × 4 sensor array with a micro-heater and ceramic chip. The device is designed in a small size for portability, including the internal eight-channel sensor array. In2O3 NRs and WO3 NRs manufactured through the E-beam evaporator’s glancing angle method were used as sensing materials. Pt, Pd, and Au metal catalysts were decorated for each channel to enhance functionality. The sensor array was measured for the exhaled gas biomarkers CH3COCH3, NO2, and H2S to confirm the respiratory diagnostic performance. Through this operation, the theoretical detection limit was calculated as 1.48 ppb for CH3COCH3, 1.9 ppt for NO2, and 2.47 ppb for H2S. This excellent detection performance indicates that our sensor array detected the CH3COCH3, NO2, and H2S as biomarkers, applying to the breath gas analysis. Our results showed the high potential of the gas sensor array as a non-invasive diagnostic tool that enables real-time monitoring.


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