scholarly journals A Miniaturized Amperometric Hydrogen Sulfide Sensor Applicable for Bad Breath Monitoring

Micromachines ◽  
2018 ◽  
Vol 9 (12) ◽  
pp. 612 ◽  
Author(s):  
Hithesh Gatty ◽  
Göran Stemme ◽  
Niclas Roxhed
Keyword(s):  
Hydrogen Sulfide ◽  
Microelectromechanical Systems ◽  
High Sensitivity ◽  
Fast Response ◽  
Detection Capability ◽  
Integrated Sensor ◽  
Handheld Device ◽  
Bad Breath ◽  
Breath Monitoring ◽  
Measured Sensitivity

Bad breath or halitosis affects a majority of the population from time to time, causing personal discomfort and social embarrassment. Here, we report on a miniaturized, microelectromechanical systems (MEMS)-based, amperometric hydrogen sulfide (H2S) sensor that potentially allows bad breath quantification through a small handheld device. The sensor is designed to detect H2S gas in the order of parts-per-billion (ppb) and has a measured sensitivity of 0.65 nA/ppb with a response time of 21 s. The sensor was found to be selective to NO and NH3 gases, which are normally present in the oral breath of adults. The ppb-level detection capability of the integrated sensor, combined with its relatively fast response and high sensitivity to H2S, makes the sensor potentially applicable for oral breath monitoring.

scholarly journals A novel quinoline-based colorimetric fluorescent probe for hydrogen sulfide

2020 ◽  
pp. 174751982092458
Author(s):  
Dingqiang Fu
Keyword(s):  
Hydrogen Sulfide ◽  
Fluorescent Probe ◽  
High Sensitivity ◽  
Fast Response ◽  
Naked Eye

In this article, a novel fluorescent probe was designed and synthesized based on the quinoline structure for the detection of H2S. After optical evaluation, the probe showed good characteristics, including a fast response, high sensitivity, and good selectivity. More importantly, the probe could be directly observed by the naked eye after responding to H2S and has good application value.

scholarly journals MEMS-Based Reflective Intensity-Modulated Fiber-Optic Sensor for Pressure Measurements

Sensors ◽  
2020 ◽  
Vol 20 (8) ◽  
pp. 2233 ◽  
Author(s):  
Ning Zhou ◽  
Pinggang Jia ◽  
Jia Liu ◽  
Qianyu Ren ◽  
Guowen An ◽  
...  
Keyword(s):  
Optical Fibers ◽  
Room Temperature ◽  
Microelectromechanical Systems ◽  
Fiber Optic ◽  
High Sensitivity ◽  
Fiber Optic Sensor ◽  
Pressure Measurements ◽  
Integrated Sensor ◽  
Intensity Modulated ◽  
Optic Sensor

A reflective intensity-modulated fiber-optic sensor based on microelectromechanical systems (MEMS) for pressure measurements is proposed and experimentally demonstrated. The sensor consists of two multimode optical fibers with a spherical end, a quartz tube with dual holes, a silicon sensitive diaphragm, and a high borosilicate glass substrate (HBGS). The integrated sensor has a high sensitivity due to the MEMS technique and the spherical end of the fiber. The results show that the sensor achieves a pressure sensitivity of approximately 0.139 mV/kPa. The temperature coefficient of the proposed sensor is about 0.87 mV/°C over the range of 20 °C to 150 °C. Furthermore, due to the intensity mechanism, the sensor has a relatively simple demodulation system and can respond to high-frequency pressure in real time. The dynamic response of the sensor was verified in a 1 kHz sinusoidal pressure environment at room temperature.

Reaction-based fluorescent probes for rapid detection of hydrogen sulfide in vivo

2018 ◽  
Vol 10 (33) ◽  
pp. 4079-4084 ◽  
Author(s):  
Xilang Jin ◽  
Xianglong Wu ◽  
Pu Xie ◽  
Sha Liu ◽  
Jie Wu ◽  
...  
Keyword(s):  
Hydrogen Sulfide ◽  
Real Time ◽  
Fluorescent Probes ◽  
Rapid Detection ◽  
High Sensitivity ◽  
Fast Response ◽  
Real Time Detection

The probe exhibited high sensitivity, selectivity, and fast response for real-time detection of H2S in vivo.

A TICT-based fluorescent probe for rapid and specific detection of hydrogen sulfide and its bio-imaging applications

2016 ◽  
Vol 52 (38) ◽  
pp. 6415-6418 ◽  
Author(s):  
Mingguang Ren ◽  
Beibei Deng ◽  
Xiuqi Kong ◽  
Kai Zhou ◽  
Keyin Liu ◽  
...  
Keyword(s):  
Hydrogen Sulfide ◽  
Fluorescent Probe ◽  
Rational Design ◽  
High Sensitivity ◽  
Fast Response ◽  
Living Cells ◽  
Specific Detection ◽  
Bio Imaging

Through rational design, the first TICT based fluorescent H2S probe was developed, which exhibited ideal properties such as fast response, good selectivity, high sensitivity, and it was suitable for visualization of exogenous and endogenous H2S in living cells.

scholarly journals Simulations of Benzene and Hydrogen-Sulfide Gas Detector Based on Single-Walled Carbon Nanotube over Intrinsic 4H-SiC Substrate

Micromachines ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 453 ◽  
Author(s):  
Muhammad Haroon Rashid ◽  
Ants Koel ◽  
Toomas Rang ◽  
Mehadi Hasan Ziko
Keyword(s):  
Hydrogen Sulfide ◽  
Electric Current ◽  
Semiconductor Device ◽  
Inorganic Compounds ◽  
High Sensitivity ◽  
Fast Response ◽  
Detection Mechanism ◽  
Gas Detector ◽  
Hazardous Gases ◽  
Target Molecules

Carbon nanotubes (CNTs)-based sensors have gained significant importance due to their tremendous electrical and physical attributes. CNT-based gas sensors have high sensitivity, stability, and fast response time compared to that of solid-state sensors. On exposure to a large variety of organic and inorganic compounds, the conductivity of CNT changes. This change in electrical conductivity is being used as a detection signal to detect different target molecules. Hydrogen-sulfide and benzene are hazardous gases that can cause serious health issues in humans. Therefore, it is mandatory to detect their presence in industrial and household environments. In this article, we simulated CNT-based benzene and hydrogen-sulfide sensor with a nanoscale semiconductor device simulator—Quantumwise Atomistix Toolkit (ATK). The change in the device density of states, electric current, and photocurrent in the presence of target molecules have been calculated. The change in photocurrent in the presence of target molecules has been proposed as a novel detection mechanism to improve the sensor selectivity and accuracy. This change in photocurrent as well as electric current in the presence of target molecules can be used simultaneously as detection signals. Our intension in the future is to physically fabricate this simulated device and use photocurrent as well as electric current as detection mechanisms.

A novel FRET-based fluorescent probe for the selective detection of hydrogen sulfide (H2S) and its application for bioimaging

2018 ◽  
Vol 6 (30) ◽  
pp. 4903-4908 ◽  
Author(s):  
Qi Zhao ◽  
Fangjun Huo ◽  
Jin Kang ◽  
Yongbin Zhang ◽  
Caixia Yin
Keyword(s):  
Hydrogen Sulfide ◽  
Detection Limit ◽  
Fluorescent Probe ◽  
Nude Mice ◽  
High Sensitivity ◽  
Fast Response ◽  
Living Cells ◽  
Selective Detection ◽  
Low Detection Limit ◽  
Sensitivity And Selectivity

Herein, our group developed a fast response fluorescent probe (Flu-N3) for H2S on the basis of the 7-amino-4-methylcoumarin and fluorescein FRET system with high sensitivity and selectivity and a low detection limit of 0.031 μM. Moreover, the probe was successfully applied to image exogenous and endogenous H2S in living cells and nude mice.

scholarly journals Tin Disulfide-Coated Microfiber for Humidity Sensing with Fast Response and High Sensitivity

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 648
Author(s):  
Aijie Liang ◽  
Jingyuan Ming ◽  
Wenguo Zhu ◽  
Heyuan Guan ◽  
Xinyang Han ◽  
...  
Keyword(s):  
Humidity Sensor ◽  
Small Diameter ◽  
High Sensitivity ◽  
Large Change ◽  
Small Variation ◽  
Response Speed ◽  
Fast Response ◽  
Tin Disulfide ◽  
Recovery Times ◽  
Response And Recovery

Breath monitoring is significant in assessing human body conditions, such as cardiac and pulmonary symptoms. Optical fiber-based sensors have attracted much attention since they are immune to electromagnetic radiation, thus are safe for patients. Here, a microfiber (MF) humidity sensor is fabricated by coating tin disulfide (SnS2) nanosheets onto the surface of MF. The small diameter (~8 μm) and the long length (~5 mm) of the MF promise strong interaction between guiding light and SnS2. Thus, a small variation in the relative humidity (RH) will lead to a large change in optical transmitted power. A high RH sensitivity of 0.57 dB/%RH is therefore achieved. The response and recovery times are estimated to be 0.08 and 0.28 s, respectively. The high sensitivity and fast response speed enable our SnS2-MF sensor to monitor human breath in real time.

scholarly journals A Full-Range Flexible and Printed Humidity Sensor Based on a Solution-Processed P(VDF-TrFE)/Graphene-Flower Composite

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1915
Author(s):  
Shenawar Ali Khan ◽  
Muhammad Saqib ◽  
Muhammad Muqeet Rehman ◽  
Hafiz Mohammad Mutee Ur Rehman ◽  
Sheik Abdur Rahman ◽  
...  
Keyword(s):  
Active Layer ◽  
Humidity Sensor ◽  
High Reliability ◽  
Full Range ◽  
High Sensitivity ◽  
Fast Response ◽  
Considerable Change ◽  
Relative Humidity Range ◽  
Response And Recovery ◽  
Proportional Relationship

A novel composite based on a polymer (P(VDF-TrFE)) and a two-dimensional material (graphene flower) was proposed as the active layer of an interdigitated electrode (IDEs) based humidity sensor. Silver (Ag) IDEs were screen printed on a flexible polyethylene terephthalate (PET) substrate followed by spin coating the active layer of P(VDF-TrFE)/graphene flower on its surface. It was observed that this sensor responds to a wide relative humidity range (RH%) of 8–98% with a fast response and recovery time of 0.8 s and 2.5 s for the capacitance, respectively. The fabricated sensor displayed an inversely proportional response between capacitance and RH%, while a directly proportional relationship was observed between its impedance and RH%. P(VDF-TrFE)/graphene flower-based flexible humidity sensor exhibited high sensitivity with an average change of capacitance as 0.0558 pF/RH%. Stability of obtained results was monitored for two weeks without any considerable change in the original values, signifying its high reliability. Various chemical, morphological, and electrical characterizations were performed to comprehensively study the humidity-sensing behavior of this advanced composite. The fabricated sensor was successfully used for the applications of health monitoring and measuring the water content in the environment.

scholarly journals Alcohol-based highly conductive polymer for conformal nanocoatings on hydrophobic surfaces toward a highly sensitive and stable pressure sensor

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Jung Joon Lee ◽  
Srinivas Gandla ◽  
Byeongjae Lim ◽  
Sunju Kang ◽  
Sunyoung Kim ◽  
...  
Keyword(s):  
Pressure Sensor ◽  
Mechanical Stability ◽  
Exchange Process ◽  
Conductive Polymer ◽  
High Sensitivity ◽  
Fast Response ◽  
Pdms Surface ◽  
Practical Applications ◽  
Sensor Applications ◽  
Water Based

Abstract Conformal and ultrathin coating of highly conductive PEDOT:PSS on hydrophobic uneven surfaces is essential for resistive-based pressure sensor applications. For this purpose, a water-based poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) solution was successfully exchanged to an organic solvent-based PEDOT:PSS solution without any aggregation or reduction in conductivity using the ultrafiltration method. Among various solvents, the ethanol (EtOH) solvent-exchanged PEDOT:PSS solution exhibited a contact angle of 34.67°, which is much lower than the value of 96.94° for the water-based PEDOT:PSS solution. The optimized EtOH-based PEDOT:PSS solution exhibited conformal and uniform coating, with ultrathin nanocoated films obtained on a hydrophobic pyramid polydimethylsiloxane (PDMS) surface. The fabricated pressure sensor showed high performances, such as high sensitivity (−21 kPa−1 in the low pressure regime up to 100 Pa), mechanical stability (over 10,000 cycles without any failure or cracks) and a fast response time (90 ms). Finally, the proposed pressure sensor was successfully demonstrated as a human blood pulse rate sensor and a spatial pressure sensor array for practical applications. The solvent exchange process using ultrafiltration for these applications can be utilized as a universal technique for improving the coating property (wettability) of conducting polymers as well as various other materials.

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