scholarly journals Fast Detection of 2,4,6-Trinitrotoluene (TNT) at ppt Level by a Laser-Induced Immunofluorometric Biosensor

Biosensors ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 89
Author(s):  
Martin Paul ◽  
Georg Tscheuschner ◽  
Stefan Herrmann ◽  
Michael G. Weller
Keyword(s):  
Detection System ◽  
Complementary Metal Oxide Semiconductor ◽  
Time Frame ◽  
Cross Reactivity ◽  
Oxide Semiconductor ◽  
Fluorescent Label ◽  
Analytical Sensitivity ◽  
Reactivity Test ◽  
Glass Column ◽  
Sports Venues

The illegal use of explosives by terrorists and other criminals is an increasing issue in public spaces, such as airports, railway stations, highways, sports venues, theaters, and other large buildings. Security in these environments can be achieved by different means, including the installation of scanners and other analytical devices to detect ultra-small traces of explosives in a very short time-frame to be able to take action as early as possible to prevent the detonation of such devices. Unfortunately, an ideal explosive detection system still does not exist, which means that a compromise is needed in practice. Most detection devices lack the extreme analytical sensitivity, which is nevertheless necessary due to the low vapor pressure of nearly all explosives. In addition, the rate of false positives needs to be virtually zero, which is also very difficult to achieve. Here we present an immunosensor system based on kinetic competition, which is known to be very fast and may even overcome affinity limitation, which impairs the performance of many traditional competitive assays. This immunosensor consists of a monolithic glass column with a vast excess of immobilized hapten, which traps the fluorescently labeled antibody as long as no explosive is present. In the case of the explosive 2,4,6-trinitrotoluene (TNT), some binding sites of the antibody will be blocked, which leads to an immediate breakthrough of the labeled protein, detectable by highly sensitive laser-induced fluorescence with the help of a Peltier-cooled complementary metal-oxide-semiconductor (CMOS) camera. Liquid handling is performed with high-precision syringe pumps and chip-based mixing-devices and flow-cells. The system achieved limits of detection of 1 pM (1 ppt) of the fluorescent label and around 100 pM (20 ppt) of TNT. The total assay time is less than 8 min. A cross-reactivity test with 5000 pM solutions showed no signal by pentaerythritol tetranitrate (PETN), 1,3,5-trinitroperhydro-1,3,5-triazine (RDX), and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX). This immunosensor belongs to the most sensitive and fastest detectors for TNT with no significant cross-reactivity by non-related compounds. The consumption of the labeled antibody is surprisingly low: 1 mg of the reagent would be sufficient for more than one year of continuous biosensor operation.

scholarly journals Fast detection of 2,4,6-trinitrotoluene (TNT) at ppt level by an immunosensor based on kinetic competition

2020 ◽  
Author(s):  
Martin Paul ◽  
Georg Tscheuschner ◽  
Stefan Herrmann ◽  
Michael G. Weller
Keyword(s):  
Detection System ◽  
Time Frame ◽  
Cross Reactivity ◽  
Fluorescent Label ◽  
Analytical Sensitivity ◽  
Railway Stations ◽  
Fast Detection ◽  
Reactivity Test ◽  
Glass Column ◽  
Short Time

The illegal use of explosives by terrorists and other criminals is an increasing issue in public spaces, such as airports, railway stations, highways, sports arenas, theaters, and other large buildings. Security in these environments can be achieved by a set of different means, including the installation of scanners and other analytical devices to detect ultra-small traces of explosives in a very short time-frame to be able to take action as early as possible to prevent the detonation of such devices. Unfortunately, an ideal explosive detection system still does not exist, which means that a compromise is needed in practice. Most detection devices lack the extreme analytical sensitivity, which is nevertheless necessary due to the low vapor pressure of nearly all explosives. In addition, the rate of false positives needs to be virtually zero, which is also very difficult to achieve. Here we present an immunosensor system based on kinetic competition, which is known to be very fast and may even overcome affinity limitation, which impairs the performance of many traditional competitive assays. This immunosensor consists of a monolithic glass column with a vast excess of immobilized hapten, which traps the fluorescently labeled antibody as long as no explosive is present. In the case of TNT occurring, some binding sites of the antibody will be blocked, which leads to an immediate breakthrough of the labeled protein, detectable by highly sensitive laser-induced fluorescence with the help of a Peltier-cooled CMOS camera. Liquid handling is performed with high-precision syringe pumps and chip-based mixing-devices and flow-cells. The system achieved limits of detection of 1 pM (1 ppt) of the fluorescent label and around 100 pM (20 ppt) of the explosive 2,4,6-trinitrotoluene (TNT). The total assay time is less than 8 min. A cross-reactivity test with 5000 pM solutions showed no signal by PETN, RDX, and HMX. This immunosensor belongs to the most sensitive and fastest detectors for TNT with no significant cross-reactivity by non-related compounds.

scholarly journals Design and analysis of current mirror OTA in 45 nm and 90 nm CMOS technology for bio-medical application

2020 ◽  
Vol 9 (1) ◽  
pp. 221-228
Author(s):  
Wan Mohammad Ehsan Aiman Wan Jusoh ◽  
Siti Hawa Ruslan
Keyword(s):  
Detection System ◽  
Complementary Metal Oxide Semiconductor ◽  
Medical Application ◽  
Cmos Technology ◽  
Open Loop ◽  
Oxide Semiconductor ◽  
Current Mirror ◽  
Ecg Signals ◽  
Transconductance Amplifier ◽  
And Performance

This paper proposed a design and performance analysis of current mirror operational transconductance amplifier (OTA) in 45 nm and 90 nm complementary metal oxide semiconductor (CMOS) technology for bio-medical application. Both OTAs were designed and simulated using Synopsys tools and the simulation results were analysed thoroughly. The OTAs were designed to be implemented in bio-potential signals detection system where the input signals were amplified and filtered according to the specifications. From the comparative analysis of both OTAs, the 45 nm OTA managed to produce open loop gain of 45 dB, with common mode rejection ratio (CMRR) of 93.2 dB. The 45 nm OTA produced only 1.113 μV√Hz of input referred noise at 1 Hz. The 45 nm OTA also consumed only 28.21 nW of power from ± 0.5 V supply. The low-power consumption aspect displayed by 45 nm OTA made it suitable to be implemented in bio-medical application such as bio-potential signals detection system where it can be used to amplify and filter the electrocardiogram (ECG) signals.

scholarly journals Optofluidic Formaldehyde Sensing: Towards On-Chip Integration

Micromachines ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 673 ◽  
Author(s):  
Daniel Mariuta ◽  
Arumugam Govindaraji ◽  
Stéphane Colin ◽  
Christine Barrot ◽  
Stéphane Le Calvé ◽  
...  
Keyword(s):  
Absorption Coefficient ◽  
Detection System ◽  
Fluorescence Emission ◽  
Complementary Metal Oxide Semiconductor ◽  
Image Sensor ◽  
Air Pollutant ◽  
Oxide Semiconductor ◽  
Excitation Wavelength ◽  
Formaldehyde Concentration ◽  
On Chip

Formaldehyde (HCHO), a chemical compound used in the fabrication process of a broad range of household products, is present indoors as an airborne pollutant due to its high volatility caused by its low boiling point ( T = − 19 °C). Miniaturization of analytical systems towards palm-held devices has the potential to provide more efficient and more sensitive tools for real-time monitoring of this hazardous air pollutant. This work presents the initial steps and results of the prototyping process towards on-chip integration of HCHO sensing, based on the Hantzsch reaction coupled to the fluorescence optical sensing methodology. This challenge was divided into two individually addressed problems: (1) efficient airborne HCHO trapping into a microfluidic context and (2) 3,5–diacetyl-1,4-dihydrolutidine (DDL) molecular sensing in low interrogation volumes. Part (2) was addressed in this paper by proposing, fabricating, and testing a fluorescence detection system based on an ultra-low light Complementary metal-oxide-semiconductor (CMOS) image sensor. Two three-layer fluidic cell configurations (quartz–SU-8–quartz and silicon–SU-8–quartz) were tested, with both possessing a 3.5 µL interrogation volume. Finally, the CMOS-based fluorescence system proved the capability to detect an initial 10 µg/L formaldehyde concentration fully derivatized into DDL for both the quartz and silicon fluidic cells, but with a higher signal-to-noise ratio (SNR) for the silicon fluidic cell ( S N R s i l i c o n = 6.1 ) when compared to the quartz fluidic cell ( S N R q u a r t z = 4.9 ). The signal intensity enhancement in the silicon fluidic cell was mainly due to the silicon absorption coefficient at the excitation wavelength,   a ( λ a b s = 420   nm ) = 5 × 10 4   cm − 1 , which is approximately five times higher than the absorption coefficient at the fluorescence emission wavelength, a ( λ e m = 515   nm ) = 9.25 × 10 3   cm − 1 .

scholarly journals Homodyne Spectroscopy with Broadband Terahertz Power Detector Based on 90-nm Silicon CMOS Transistor

2021 ◽  
Vol 11 (1) ◽  
pp. 412
Author(s):  
Kęstutis Ikamas ◽  
Dmytro B. But ◽  
Alvydas Lisauskas
Keyword(s):  
Continuous Wave ◽  
Detection System ◽  
Signal To Noise Ratio ◽  
High Sensitivity ◽  
Complementary Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Integration Time ◽  
Thz Spectroscopy ◽  
Homodyne Detection ◽  
Cmos Transistor

Over the last two decades, photomixer-based continuous wave systems developed into versatile and practical tools for terahertz (THz) spectroscopy. The high responsivity to the THz field amplitude of photomixer-based systems is predetermined by the homodyne detection principle that allows the system to have high sensitivity. Here, we show that the advantages of homodyne detection can be exploited with broadband power detectors combined with two photomixer sources. For this, we employ a THz detector based on a complementary metal-oxide-semiconductor field-effect transistor and a broadband bow-tie antenna (TeraFET). At 500 GHz and an effective noise bandwidth of 1 Hz, the response from one photomixer-based THz source resulted in an about 43 dB signal-to-noise ratio (SNR). We demonstrate that by employing a homodyne detection system by overlaying the radiation from two photomixers, the SNR can reach up to 70 dB at the same frequency with an integration time 100 ms. The improvement in SNR and the spectroscopic evidence for water vapor lines demonstrated up to 2.2 THz allow us to conclude that these detectors can be successfully used in practical continuous wave THz spectrometry systems.

scholarly journals Cocaine Detection by a Laser-induced Immunofluorometric Biosensor

2021 ◽  
Author(s):  
Martin Paul ◽  
Robert Tannenberg ◽  
Georg Tscheuschner ◽  
Marco Wilke ◽  
Michael G. Weller
Keyword(s):  
Complementary Metal Oxide Semiconductor ◽  
Time Frame ◽  
Oxide Semiconductor ◽  
Affinity Column ◽  
Illegal Drugs ◽  
Flow Cells ◽  
Wipe Sampling ◽  
Reasonable Time Frame ◽  
Assay Time ◽  
Cocaine Detection

The trafficking of illegal drugs by criminal networks at borders, harbors, or airports is an increasing issue in public health as these routes ensure the main supply of illegal drugs. The prevention of drug smuggling, including the installation of scanners and other analytical devices to detect ultra-small traces of drugs within a reasonable time frame, remains a challenge. The presented immunosensor is based on a monolithic affinity column with a large excess of immobilized hapten, which traps fluorescently labeled antibodies as long as the analyte cocaine is absent. In the presence of the drug, some binding sites of the antibody will be blocked, which leads to an immediate breakthrough of the labeled protein, detectable by highly sensitive laser-induced fluorescence with the help of a Peltier-cooled complementary metal-oxide-semiconductor (CMOS) camera. Liquid handling is performed with high-precision syringe pumps and microfluidic chip-based mixing devices and flow cells. The biosensor achieved limits of detection of 23 pM (7 ppt) of cocaine with a response time of 90 seconds and a total assay time below 3 minutes. With surface wipe sampling, the biosensor was able to detect 300 pg of cocaine. This immunosensor belongs to the most sensitive and fastest detectors for cocaine and offers near-continuous analyte measurement.

scholarly journals Saliva-Dry LAMP: A Rapid Near-Patient Detection System for SARS-CoV-2.

2021 ◽  
Author(s):  
Noah Toppings ◽  
Abu Mohon ◽  
Yoonjung Lee ◽  
Hitendra Kumar ◽  
Daniel Lee ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Detection System ◽  
Turnaround Time ◽  
Cross Reactivity ◽  
Molecular Testing ◽  
Fluorometric Detection ◽  
Analytical Sensitivity ◽  
Sample Collection ◽  
Rt Pcr ◽  
Percent Agreement

Abstract The highly infectious nature of SARS-CoV-2 necessitates the use of widespread testing to control the spread of the virus. Presently, the standard molecular testing method (reverse transcriptase-polymerase chain reaction, RT-PCR) is restricted to the laboratory, time-consuming, and costly. This increases the turnaround time for getting test results. The study sought to develop a rapid, near-patient saliva-based test for COVID-19 with similar accuracy to that of standard RT-PCR tests. A lyophilized dual-target reverse transcription-loop-mediated isothermal amplification (RT-LAMP) test with fluorometric detection by the naked eye. The assay relies on dry reagents that are room temperature stable. A device containing a centrifuge, heat block, and blue LED light system was manufactured to reduce the cost of performing the assay. This test has a limit of detection of 1 copy/µL and achieved positive percent agreement of 100% [95% CI 88.43% to 100.0%] and negative percent agreement of 96.7% [95% CI 82.78% to 99.92%] on saliva. Saliva-Dry LAMP can be completed in 105 minutes. Precision, cross-reactivity, and interfering substances analysis met international regulatory standards. The combination of ease of sample collection, dry reagents, visual detection, low capital equipment cost, and excellent analytical sensitivity make Saliva-Dry LAMP particularly useful for resource-limited settings.

scholarly journals Microwave Imaging Using CMOS Integrated Circuits with Rotating 4 × 4 Antenna Array on a Breast Phantom

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Hang Song ◽  
Afreen Azhari ◽  
Xia Xiao ◽  
Eiji Suematsu ◽  
Hiromasa Watanabe ◽  
...  
Keyword(s):  
Integrated Circuits ◽  
Antenna Array ◽  
Detection System ◽  
Reference Signal ◽  
Complementary Metal Oxide Semiconductor ◽  
Confocal Imaging ◽  
Oxide Semiconductor ◽  
Cmos Integrated Circuits ◽  
Alignment Algorithm ◽  
Breast Phantom

A digital breast cancer detection system using 65 nm technology complementary metal oxide semiconductor (CMOS) integrated circuits with rotating 4 × 4 antenna array is presented. Gaussian monocycle pulses are generated by CMOS logic circuits and transmitted by a 4 × 4 matrix antenna array via two CMOS single-pole-eight-throw (SP8T) switching matrices. Radar signals are received and converted to digital signals by CMOS equivalent time sampling circuits. By rotating the 4 × 4 antenna array, the reference signal is obtained by averaging the waveforms from various positions to extract the breast phantom target response. A signal alignment algorithm is proposed to compensate the phase shift of the signals caused by the system jitter. After extracting the scattered signal from the target, a bandpass filter is applied to reduce the noise caused by imperfect subtraction between original and the reference signals. The confocal imaging algorithm for rotating antennas is utilized to reconstruct the breast image. A 1 cm3 bacon block as a cancer phantom target in a rubber substrate as a breast fat phantom can be detected with reduced artifacts.

scholarly journals Cocaine Detection by a Laser-Induced Immunofluorometric Biosensor

Biosensors ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 313
Author(s):  
Martin Paul ◽  
Robert Tannenberg ◽  
Georg Tscheuschner ◽  
Marco Ponader ◽  
Michael G. Weller
Keyword(s):  
Complementary Metal Oxide Semiconductor ◽  
Time Frame ◽  
Oxide Semiconductor ◽  
Affinity Column ◽  
Illegal Drugs ◽  
Flow Cells ◽  
Wipe Sampling ◽  
Reasonable Time Frame ◽  
Assay Time ◽  
Cocaine Detection

The trafficking of illegal drugs by criminal networks at borders, harbors, or airports is an increasing issue for public health as these routes ensure the main supply of illegal drugs. The prevention of drug smuggling, including the installation of scanners and other analytical devices to detect small traces of drugs within a reasonable time frame, remains a challenge. The presented immunosensor is based on a monolithic affinity column with a large excess of immobilized hapten, which traps fluorescently labeled antibodies as long as the analyte cocaine is absent. In the presence of the drug, some binding sites of the antibody will be blocked, which leads to an immediate breakthrough of the labeled protein, detectable by highly sensitive laser-induced fluorescence with the help of a Peltier-cooled complementary metal-oxide-semiconductor (CMOS) camera. Liquid handling is performed with high-precision syringe pumps and microfluidic chip-based mixing devices and flow cells. The biosensor achieved limits of detection of 7 ppt (23 pM) of cocaine with a response time of 90 s and a total assay time below 3 min. With surface wipe sampling, the biosensor was able to detect 300 pg of cocaine. This immunosensor belongs to the most sensitive and fastest detectors for cocaine and offers near-continuous analyte measurement.

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