Pub Date : 2024-11-12DOI: 10.1021/acssensors.4c01284
Kyusung Kim, Phuwadej Pornaroontham, Hojung Yun, Sungmin Kim, Pilgyu Choi, Yoshitake Masuda
In the gas-sensing mechanism of a metal-oxide-semiconductor (n-type) gas sensor, oxygen adsorption or desorption on the oxide surface leads to an increase or decrease in the resistance of the gas sensor system. Additionally, oxygen can be adsorbed again at the location where initially adsorbed oxygen reacted with the target gas. Thus, the adsorption–desorption equilibrium of the reducing gas on the oxide surface is a significant factor in determining the sensitivity and reaction rate. In particular, for ultralow-concentration gas measurements, the relative concentration of oxygen was very high. To design an ultrasensitive gas sensor, not only the reaction of the target gas but also the competing reaction between the target gas and oxygen must be considered. Although qualitative investigations of these complex relationships have been performed according to the gas concentration and flow rate, reliable quantitative results are limited. In this study, a quantitative approach was used to understand the correlation between oxygen and a target gas by applying data analysis methods. We investigated the behavior of oxygen and the target molecules depending on the gas concentration and flow rate using the parts per billion level of the acetone gas sensor. Initial response data according to various detection conditions were processed using principal component analysis and K-means clustering; as a result, four types of reaction behaviors were inferred for 15 types of reaction conditions. Furthermore, the response time, depending on the detection conditions, can be distinguished using the suggested categorization. Our investigation suggests a possibility beyond simple optimization through the data analysis of the gas-sensing results.
{"title":"Insights into Target Gas–Oxygen Interactions in Highly Sensitive Gas Sensors Using Data-Driven Methods","authors":"Kyusung Kim, Phuwadej Pornaroontham, Hojung Yun, Sungmin Kim, Pilgyu Choi, Yoshitake Masuda","doi":"10.1021/acssensors.4c01284","DOIUrl":"https://doi.org/10.1021/acssensors.4c01284","url":null,"abstract":"In the gas-sensing mechanism of a metal-oxide-semiconductor (n-type) gas sensor, oxygen adsorption or desorption on the oxide surface leads to an increase or decrease in the resistance of the gas sensor system. Additionally, oxygen can be adsorbed again at the location where initially adsorbed oxygen reacted with the target gas. Thus, the adsorption–desorption equilibrium of the reducing gas on the oxide surface is a significant factor in determining the sensitivity and reaction rate. In particular, for ultralow-concentration gas measurements, the relative concentration of oxygen was very high. To design an ultrasensitive gas sensor, not only the reaction of the target gas but also the competing reaction between the target gas and oxygen must be considered. Although qualitative investigations of these complex relationships have been performed according to the gas concentration and flow rate, reliable quantitative results are limited. In this study, a quantitative approach was used to understand the correlation between oxygen and a target gas by applying data analysis methods. We investigated the behavior of oxygen and the target molecules depending on the gas concentration and flow rate using the parts per billion level of the acetone gas sensor. Initial response data according to various detection conditions were processed using principal component analysis and K-means clustering; as a result, four types of reaction behaviors were inferred for 15 types of reaction conditions. Furthermore, the response time, depending on the detection conditions, can be distinguished using the suggested categorization. Our investigation suggests a possibility beyond simple optimization through the data analysis of the gas-sensing results.","PeriodicalId":24,"journal":{"name":"ACS Sensors","volume":"10 1","pages":""},"PeriodicalIF":8.9,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142601430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The detection of acetone in human exhaled breath is crucial for the noninvasive diagnosis of diabetes. However, the direct and reliable detection of acetone in exhaled breath with high humidity at the parts per billion level remains a great challenge. Here, an ultrasensitive acetone gas sensor based on a K/Sn–Co3O4 porous microsphere was reported. The sensor demonstrates a detection limit of up to 100 ppb, along with excellent repeatability and selectivity. Remarkably, without the removal of water vapor from exhaled breath, the sensor can accurately distinguish diabetic patients and healthy individuals according to the difference in acetone concentrations, demonstrating its great potential for diabetes diagnosis. The enhanced sensitivity of the sensor is attributed to the increased oxygen adsorption on the material surface due to K/Sn codoping and the stronger coadsorption of Sn–K atoms to acetone molecules. These findings shed light on the mechanisms underlying the sensor’s improved performance.
{"title":"Ultrasensitive Acetone Gas Sensor Based on a K/Sn–Co3O4 Porous Microsphere for Noninvasive Diabetes Diagnosis","authors":"Ertai Na, Siwen Tao, Wenxue Wang, Jiayu Li, Yanan Guo, Ruiqin Gao, Qiuju Li, Fanghui Wang, Chongbo Zhang, Guo-Dong Li","doi":"10.1021/acssensors.4c02009","DOIUrl":"https://doi.org/10.1021/acssensors.4c02009","url":null,"abstract":"The detection of acetone in human exhaled breath is crucial for the noninvasive diagnosis of diabetes. However, the direct and reliable detection of acetone in exhaled breath with high humidity at the parts per billion level remains a great challenge. Here, an ultrasensitive acetone gas sensor based on a K/Sn–Co<sub>3</sub>O<sub>4</sub> porous microsphere was reported. The sensor demonstrates a detection limit of up to 100 ppb, along with excellent repeatability and selectivity. Remarkably, without the removal of water vapor from exhaled breath, the sensor can accurately distinguish diabetic patients and healthy individuals according to the difference in acetone concentrations, demonstrating its great potential for diabetes diagnosis. The enhanced sensitivity of the sensor is attributed to the increased oxygen adsorption on the material surface due to K/Sn codoping and the stronger coadsorption of Sn–K atoms to acetone molecules. These findings shed light on the mechanisms underlying the sensor’s improved performance.","PeriodicalId":24,"journal":{"name":"ACS Sensors","volume":"6 1","pages":""},"PeriodicalIF":8.9,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142601464","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-11DOI: 10.1021/acssensors.4c01739
Jin Yoo, Donggyu Lee, Soobeen Lee, Seungmin Kang, Hye In Kim, Yoon Jeong Jang, Jihyun Kim, Tai Hyun Park
Nerve agents are toxic organophosphorus chemicals and acetylcholinesterase inhibitors that have been used in terrorist acts. Because they exhibit fatal toxic effects in small amounts, technology is required to detect and identify them early. Research for nerve agent detection using structural simulants of real agents may not function properly for real agents depending on the selectivity of the sensor. For practical sensor applications, experiments were conducted using two toxic nerve agents, sarin and VX, which are used in terrorism and attacks. Herein, human olfactory receptors (ORs) were used as sensing materials with high selectivity and sensitivity to target substances. Through molecular dynamic simulations, the interaction results between ORs and target materials were compared, and an OR combination that could distinguish structurally similar target materials was selected. Four types of OR were combined with a graphene/MoS2-based n-type field-effect transistor platform to create a bioelectronic nose that showed remarkable sensitivity and a stable basal current to convert the biological signals of the OR with target substances into electrical signals. This study developed a nerve agent detection technology using multiple OR sensing signals, advocating combinatorial pattern recognition, which is the core of the human olfactory mechanism. The bioelectronic nose effectively distinguishes structurally similar nerve agents using pattern signals.
{"title":"Combinatorial Pattern Response of Bioelectronic Nose for the Detection of Real Nerve Agents","authors":"Jin Yoo, Donggyu Lee, Soobeen Lee, Seungmin Kang, Hye In Kim, Yoon Jeong Jang, Jihyun Kim, Tai Hyun Park","doi":"10.1021/acssensors.4c01739","DOIUrl":"https://doi.org/10.1021/acssensors.4c01739","url":null,"abstract":"Nerve agents are toxic organophosphorus chemicals and acetylcholinesterase inhibitors that have been used in terrorist acts. Because they exhibit fatal toxic effects in small amounts, technology is required to detect and identify them early. Research for nerve agent detection using structural simulants of real agents may not function properly for real agents depending on the selectivity of the sensor. For practical sensor applications, experiments were conducted using two toxic nerve agents, sarin and VX, which are used in terrorism and attacks. Herein, human olfactory receptors (ORs) were used as sensing materials with high selectivity and sensitivity to target substances. Through molecular dynamic simulations, the interaction results between ORs and target materials were compared, and an OR combination that could distinguish structurally similar target materials was selected. Four types of OR were combined with a graphene/MoS<sub>2</sub>-based n-type field-effect transistor platform to create a bioelectronic nose that showed remarkable sensitivity and a stable basal current to convert the biological signals of the OR with target substances into electrical signals. This study developed a nerve agent detection technology using multiple OR sensing signals, advocating combinatorial pattern recognition, which is the core of the human olfactory mechanism. The bioelectronic nose effectively distinguishes structurally similar nerve agents using pattern signals.","PeriodicalId":24,"journal":{"name":"ACS Sensors","volume":"28 1","pages":""},"PeriodicalIF":8.9,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142598570","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-11DOI: 10.1021/acssensors.4c01631
Yaru Li, Lu Zhao, Jiali Wang, Long Ma, Yunfeng Bai, Feng Feng
Rapid and accurate detection is a prerequisite for precise clinical diagnostics, ensuring food safety, and facilitating biotechnological applications. The Argonaute system, as a cutting-edge technique, has been successfully repurposed in biosensing beyond the CRISPR/Cas system (clustered regularly interspaced short palindromic repeats and CRISPR-associated proteins), which has been extensively researched, but recognition of PAM sequences remains restricted. Argonaute, as a programmable and target-activated nuclease, is repurposed for fabricating novel detection methods due to its unparalleled biological features. In this comprehensive review, we initially elaborate on the current methods for nucleic acid testing and programmable nucleases, followed by delving into the structure and nuclease activity of the Argonaute system. The advantages of Argonaute compared with the CRISPR/Cas system in nucleic acid detection are highlighted and discussed. Furthermore, we summarize the applications of Argonaute-based nucleic acid detection and provide an in-depth analysis of future perspectives and challenges. Recent research has demonstrated that Argonaute-based biosensing is an innovative and rapidly advancing technology that can overcome the limitations of existing methods and potentially replace them. In summary, the implementation of Argonaute and its integration with other technologies hold promise in developing customized and intelligent detection methods for nucleic acid testing across various aspects.
{"title":"Argonaute-Based Nucleic Acid Detection Technology: Advantages, Current Status, Challenges, and Perspectives","authors":"Yaru Li, Lu Zhao, Jiali Wang, Long Ma, Yunfeng Bai, Feng Feng","doi":"10.1021/acssensors.4c01631","DOIUrl":"https://doi.org/10.1021/acssensors.4c01631","url":null,"abstract":"Rapid and accurate detection is a prerequisite for precise clinical diagnostics, ensuring food safety, and facilitating biotechnological applications. The Argonaute system, as a cutting-edge technique, has been successfully repurposed in biosensing beyond the CRISPR/Cas system (clustered regularly interspaced short palindromic repeats and CRISPR-associated proteins), which has been extensively researched, but recognition of PAM sequences remains restricted. Argonaute, as a programmable and target-activated nuclease, is repurposed for fabricating novel detection methods due to its unparalleled biological features. In this comprehensive review, we initially elaborate on the current methods for nucleic acid testing and programmable nucleases, followed by delving into the structure and nuclease activity of the Argonaute system. The advantages of Argonaute compared with the CRISPR/Cas system in nucleic acid detection are highlighted and discussed. Furthermore, we summarize the applications of Argonaute-based nucleic acid detection and provide an in-depth analysis of future perspectives and challenges. Recent research has demonstrated that Argonaute-based biosensing is an innovative and rapidly advancing technology that can overcome the limitations of existing methods and potentially replace them. In summary, the implementation of Argonaute and its integration with other technologies hold promise in developing customized and intelligent detection methods for nucleic acid testing across various aspects.","PeriodicalId":24,"journal":{"name":"ACS Sensors","volume":"1 1","pages":""},"PeriodicalIF":8.9,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142598562","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We developed a nanobody-based homogeneous bioluminescent immunosensor to achieve a one-pot detection for point-of-care testing (POCT). This immunosensor was named BRET nano Q-body as its emission color changes via bioluminescence resonance energy transfer (BRET) upon antigen addition. NanoLuc luciferase and a cysteine-containing tag were fused to the N-terminus of the nanobody, which was labeled with a fluorescent dye via thiol-maleimide Michael addition. The nanobody employed in this proof-of-principle experiment recognizes methotrexate (MTX), a chemotherapeutic agent. After optimizing the fluorescent dye and linker, the BRET nano Q-body dose-dependently exhibited a greater than 7-fold increase in emission ratio (TAMRA/NanoLuc). Moreover, we found its superior thermostability endurance in organic solvents, reducing agents, and detergents due to the robust structure of nanobody, as well as accommodation in biological fluids, such as milk, serum, and whole blood without dilution, with limits of detection of 0.50, 1.6, and 3.7 nM, respectively. Furthermore, the BRET nano Q-body was subjected to lyophilization and fabricated into a paper device, which markedly improved its portability and enabled more than one month of storage at 25 °C. The paper device also performed appropriate functions in the biological fluids without any dilution and can be used for on-site therapeutic drug monitoring of MTX. Altogether, we developed a powerful tool, the BRET nano Q-body, for POCT, and demonstrated its applicability in several biological fluids. In addition, we confirmed the feasibility of paper devices, which are expected to be transformative for in situ detection in therapeutic, diagnostic, and environmental applications.
{"title":"BRET Nano Q-Body: A Nanobody-Based Ratiometric Bioluminescent Immunosensor for Point-of-Care Testing","authors":"Yinghui Yang, Akihito Inoue, Takanobu Yasuda, Hiroshi Ueda, Bo Zhu, Tetsuya Kitaguchi","doi":"10.1021/acssensors.4c01800","DOIUrl":"https://doi.org/10.1021/acssensors.4c01800","url":null,"abstract":"We developed a nanobody-based homogeneous bioluminescent immunosensor to achieve a one-pot detection for point-of-care testing (POCT). This immunosensor was named BRET nano Q-body as its emission color changes via bioluminescence resonance energy transfer (BRET) upon antigen addition. NanoLuc luciferase and a cysteine-containing tag were fused to the N-terminus of the nanobody, which was labeled with a fluorescent dye via thiol-maleimide Michael addition. The nanobody employed in this proof-of-principle experiment recognizes methotrexate (MTX), a chemotherapeutic agent. After optimizing the fluorescent dye and linker, the BRET nano Q-body dose-dependently exhibited a greater than 7-fold increase in emission ratio (TAMRA/NanoLuc). Moreover, we found its superior thermostability endurance in organic solvents, reducing agents, and detergents due to the robust structure of nanobody, as well as accommodation in biological fluids, such as milk, serum, and whole blood without dilution, with limits of detection of 0.50, 1.6, and 3.7 nM, respectively. Furthermore, the BRET nano Q-body was subjected to lyophilization and fabricated into a paper device, which markedly improved its portability and enabled more than one month of storage at 25 °C. The paper device also performed appropriate functions in the biological fluids without any dilution and can be used for on-site therapeutic drug monitoring of MTX. Altogether, we developed a powerful tool, the BRET nano Q-body, for POCT, and demonstrated its applicability in several biological fluids. In addition, we confirmed the feasibility of paper devices, which are expected to be transformative for in situ detection in therapeutic, diagnostic, and environmental applications.","PeriodicalId":24,"journal":{"name":"ACS Sensors","volume":"37 1","pages":""},"PeriodicalIF":8.9,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142598563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ensuring water-fouling-free operation of semiconductor-based gas sensors is essential to maintaining their accuracy, reliability, and stability across diverse applications. Despite the use of hydrophobic strategies to prevent external water intrusion, addressing in situ-produced water transport during H2 detection remains a challenge. Herein, we construct a novel waterproof H2 sensor by integrating single-atom Ru(III) self-assembly with monolayer amphiphiles embedded in MoS2. The unique monolayer structure enables the sensor to detect H2 in the presence of water, as well as facilitate the self-transport of in situ-generated water from the H2–O2 reaction during H2 detection. Molecular dynamics simulations reveal that monolayer amphiphiles exhibit a higher water diffusion coefficient than multilayer amphiphiles, making them more advantageous for removing in situ-produced water. Deployable on mobile platforms, it enables wireless H2cat detection for up to 6 months, without the introduction of protective membranes against dust and water ingress. This work not only enhances the performance of H2 detection but also introduces a new concept for the advancement of stable water-sensitive sensors.
{"title":"Monolayer Amphiphiles Hydrophobicize MoS2-Mediated Real-Time Water Removal for Efficient Waterproof Hydrogen Detection","authors":"Zongke Li, Xiao Wu, Wen Wang, Xiaoming Wen, Feng Niu, Dandan Han, Wei Zhong, Vitaly V. Ordomsky, Qiyan Wang, Ronghan Wei, Tianshui Liang","doi":"10.1021/acssensors.4c01696","DOIUrl":"https://doi.org/10.1021/acssensors.4c01696","url":null,"abstract":"Ensuring water-fouling-free operation of semiconductor-based gas sensors is essential to maintaining their accuracy, reliability, and stability across diverse applications. Despite the use of hydrophobic strategies to prevent external water intrusion, addressing in situ-produced water transport during H<sub>2</sub> detection remains a challenge. Herein, we construct a novel waterproof H<sub>2</sub> sensor by integrating single-atom Ru<sup>(III)</sup> self-assembly with monolayer amphiphiles embedded in MoS<sub>2</sub>. The unique monolayer structure enables the sensor to detect H<sub>2</sub> in the presence of water, as well as facilitate the self-transport of in situ-generated water from the H<sub>2</sub>–O<sub>2</sub> reaction during H<sub>2</sub> detection. Molecular dynamics simulations reveal that monolayer amphiphiles exhibit a higher water diffusion coefficient than multilayer amphiphiles, making them more advantageous for removing in situ-produced water. Deployable on mobile platforms, it enables wireless H<sub>2cat</sub> detection for up to 6 months, without the introduction of protective membranes against dust and water ingress. This work not only enhances the performance of H<sub>2</sub> detection but also introduces a new concept for the advancement of stable water-sensitive sensors.","PeriodicalId":24,"journal":{"name":"ACS Sensors","volume":"41 1","pages":""},"PeriodicalIF":8.9,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142598597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-10DOI: 10.1021/acssensors.4c01563
Jason A. Kapit, Sarah Youngs, William A. Pardis, Alexandra M. Padilla, Anna P. M. Michel
Existing sensors for measuring dissolved methane in situ suffer from excessively slow response times or large size and complexity. The technology reported here realizes improvements by utilizing a hollow core optical fiber (HFC) as the detection cell in an underwater infrared laser spectrometer. The sensor operates by using a polymer membrane inlet to continuously extract dissolved gas from water. Once inside the sensor, the gas passes through an HCF, within which tunable diode laser spectroscopy is used to quantify methane. The use of an HCF for the optical cell enables advantages of sensitivity, selectivity, compactness, response time, and ease of integration. A submersible prototype has been developed, characterized in the laboratory, and tested in the ocean to a depth of 2000 m. Initial laboratory environmental testing showed a pCH4 detection range up to 10,000 μatm, an uncertainty of 5.6 μatm or ±1.4% (whichever is greater) and a response time of 4.6 min over a range of controlled operating conditions. Operation at sea demonstrated its utility in generating dissolved methane maps, targeted point sampling, and water column profiling.
{"title":"An Underwater Methane Sensor Based on Laser Spectroscopy in a Hollow Core Optical Fiber","authors":"Jason A. Kapit, Sarah Youngs, William A. Pardis, Alexandra M. Padilla, Anna P. M. Michel","doi":"10.1021/acssensors.4c01563","DOIUrl":"https://doi.org/10.1021/acssensors.4c01563","url":null,"abstract":"Existing sensors for measuring dissolved methane in situ suffer from excessively slow response times or large size and complexity. The technology reported here realizes improvements by utilizing a hollow core optical fiber (HFC) as the detection cell in an underwater infrared laser spectrometer. The sensor operates by using a polymer membrane inlet to continuously extract dissolved gas from water. Once inside the sensor, the gas passes through an HCF, within which tunable diode laser spectroscopy is used to quantify methane. The use of an HCF for the optical cell enables advantages of sensitivity, selectivity, compactness, response time, and ease of integration. A submersible prototype has been developed, characterized in the laboratory, and tested in the ocean to a depth of 2000 m. Initial laboratory environmental testing showed a pCH<sub>4</sub> detection range up to 10,000 μatm, an uncertainty of 5.6 μatm or ±1.4% (whichever is greater) and a response time of 4.6 min over a range of controlled operating conditions. Operation at sea demonstrated its utility in generating dissolved methane maps, targeted point sampling, and water column profiling.","PeriodicalId":24,"journal":{"name":"ACS Sensors","volume":"10 1","pages":""},"PeriodicalIF":8.9,"publicationDate":"2024-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142598564","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The efficacy of sensors, particularly sensor arrays, lies in their selectivity. However, research on selectivity remains notably obscure and scarce. In this work, indoor pollutants (C7H8, HCHO, CH4, and NO2) were chosen as the target gas. Following the screening of six oxides from previous work, temperature-programmed desorption/reduction experiments were conducted to delve into the origins of selectivity. The results explicate the superiority of NiO in detecting toluene and unveil the distinctive NO2 sensing mechanism of WO3 sensors. Based on the sensor array comprising these oxides, it can clearly detect low concentrations of C7H8 (S = 1.6 to 50 ppb), HCHO (S = 1.4 to 50 ppb), and NO2 (S = 3.3 to 50 ppb), which satisfies the requisites of indoor air monitoring. Meanwhile, three machine learning models (Extreme Gradient Boosting, Support Vector Machine, and Back Propagation Neural Network) are employed for gas classification. The classification accuracies of these models are 95.45%, 100%, and 100%, while the R2 values of the concentration prediction are 99.65%, 94.9%, and 98.04%, respectively, indicating the rationality of material selection. Furthermore, it can still achieve relatively high accuracy in gas classification (94.12%) and concentration prediction (89.36%), even for gas mixtures of four gases. Finally, an indoor air quality monitoring system is developed, which enables real-time monitoring of indoor gas quality through the Internet of Things.
{"title":"Indoor Air Quality Monitoring System with High Accuracy of Gas Classification and Concentration Prediction via Selective Mechanism Research","authors":"Xueqin Gong, Zhipeng Li, Liupeng Zhao, Tianshuang Wang, Rui Jin, Xu Yan, Fangmeng Liu, Peng Sun, Geyu Lu","doi":"10.1021/acssensors.4c01178","DOIUrl":"https://doi.org/10.1021/acssensors.4c01178","url":null,"abstract":"The efficacy of sensors, particularly sensor arrays, lies in their selectivity. However, research on selectivity remains notably obscure and scarce. In this work, indoor pollutants (C<sub>7</sub>H<sub>8</sub>, HCHO, CH<sub>4</sub>, and NO<sub>2</sub>) were chosen as the target gas. Following the screening of six oxides from previous work, temperature-programmed desorption/reduction experiments were conducted to delve into the origins of selectivity. The results explicate the superiority of NiO in detecting toluene and unveil the distinctive NO<sub>2</sub> sensing mechanism of WO<sub>3</sub> sensors. Based on the sensor array comprising these oxides, it can clearly detect low concentrations of C<sub>7</sub>H<sub>8</sub> (<i>S</i> = 1.6 to 50 ppb), HCHO (<i>S</i> = 1.4 to 50 ppb), and NO<sub>2</sub> (<i>S</i> = 3.3 to 50 ppb), which satisfies the requisites of indoor air monitoring. Meanwhile, three machine learning models (Extreme Gradient Boosting, Support Vector Machine, and Back Propagation Neural Network) are employed for gas classification. The classification accuracies of these models are 95.45%, 100%, and 100%, while the <i>R</i><sup>2</sup> values of the concentration prediction are 99.65%, 94.9%, and 98.04%, respectively, indicating the rationality of material selection. Furthermore, it can still achieve relatively high accuracy in gas classification (94.12%) and concentration prediction (89.36%), even for gas mixtures of four gases. Finally, an indoor air quality monitoring system is developed, which enables real-time monitoring of indoor gas quality through the Internet of Things.","PeriodicalId":24,"journal":{"name":"ACS Sensors","volume":"18 1","pages":""},"PeriodicalIF":8.9,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142597939","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sulfur dioxide (SO2) is a common environmental pollutant with significant hazards. However, sensors for SO2 real-time monitoring at room temperature often face problems such as a poor response and sluggish recovery. In this work, a fuel cell-type gas sensor based on nitrogen-doped carbon nanotube (CNT) aerogels loaded with Cu particle electrode material and COF/Nafion composite electrolyte was developed, which exhibited excellent SO2 sensitivity and fast response/recovery. The aerogel scaffold provided a high specific surface area and high electrical conductivity, and Cu particles provided good catalytic activity to SO2. In addition, N doping further enhanced the SO2 capture capability and conductivity of the electrode material. For electrolyte construction, covalent organic framework (COF) nanosheets were synthesized by a bottom-up approach and blended with Nafion to prepare the COF/Nafion membrane; the composite membrane showed higher proton conductivity. Owing to these advantages, the fuel cell-type sensor exhibited an outstanding response of −3008.5 nA to 50 ppm of SO2 with a rapid response time (35 s) and recovery time (77 s). Moreover, the rigid nanochannels of COF nanosheets improved the water retention properties of the electrolyte; this will help to simplify the structure of fuel cell-type sensors and provide a significant stimulus for their miniaturization. Based on the great sensing performance, a fuel cell-type SO2 sensor is integrated into a portable detector and evaluated in the context of dynamic environmental monitoring. The results show that the fuel cell-type sensor with the carefully designed electrode and electrolyte will have great potential in environmental monitoring and safety assurance.
{"title":"Enhancing SO2 Sensing Performance of a Fuel Cell-Type Sensor with N-Doped Cu/CNT Aerogel Electrode and COF/Nafion Electrolyte","authors":"Lingchu Huang, Huaiyuan Sun, Weijia Li, Jianyu Zhang, Sitong Feng, Qi Lu, Tong Wang, Xishuang Liang, Fangmeng Liu, Fengmin Liu, Geyu Lu","doi":"10.1021/acssensors.4c02253","DOIUrl":"https://doi.org/10.1021/acssensors.4c02253","url":null,"abstract":"Sulfur dioxide (SO<sub>2</sub>) is a common environmental pollutant with significant hazards. However, sensors for SO<sub>2</sub> real-time monitoring at room temperature often face problems such as a poor response and sluggish recovery. In this work, a fuel cell-type gas sensor based on nitrogen-doped carbon nanotube (CNT) aerogels loaded with Cu particle electrode material and COF/Nafion composite electrolyte was developed, which exhibited excellent SO<sub>2</sub> sensitivity and fast response/recovery. The aerogel scaffold provided a high specific surface area and high electrical conductivity, and Cu particles provided good catalytic activity to SO<sub>2</sub>. In addition, N doping further enhanced the SO<sub>2</sub> capture capability and conductivity of the electrode material. For electrolyte construction, covalent organic framework (COF) nanosheets were synthesized by a bottom-up approach and blended with Nafion to prepare the COF/Nafion membrane; the composite membrane showed higher proton conductivity. Owing to these advantages, the fuel cell-type sensor exhibited an outstanding response of −3008.5 nA to 50 ppm of SO<sub>2</sub> with a rapid response time (35 s) and recovery time (77 s). Moreover, the rigid nanochannels of COF nanosheets improved the water retention properties of the electrolyte; this will help to simplify the structure of fuel cell-type sensors and provide a significant stimulus for their miniaturization. Based on the great sensing performance, a fuel cell-type SO<sub>2</sub> sensor is integrated into a portable detector and evaluated in the context of dynamic environmental monitoring. The results show that the fuel cell-type sensor with the carefully designed electrode and electrolyte will have great potential in environmental monitoring and safety assurance.","PeriodicalId":24,"journal":{"name":"ACS Sensors","volume":"95 1","pages":""},"PeriodicalIF":8.9,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142597934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-07DOI: 10.1021/acssensors.4c02739
Marti Z. Hua, Jinxin Liu, M. S. Roopesh, Xiaonan Lu
Natural toxins, mainly small molecules, are a category of chemical hazards in agri-food systems that pose threats to both public health and food security. Current standard methods for monitoring these toxins, predominantly based on liquid chromatography–mass spectrometry, are costly, labor-intensive, and complex. This study presents the development of a novel microfluidic optical aptasensor for rapid detection of small molecules based on analyte-tuned growth of gold nanoseeds combined with machine learning-enhanced spectrum analysis. We discovered and optimized a previously unreported growth pattern of aptamer-coated nanoparticles in the presence of different concentrations of analyte, enabling the detection of a major mycotoxin in food. The entire analysis was miniaturized on a customized microfluidic platform, allowing for automated spectral acquisition with precise liquid manipulation. A machine learning model, based on random forest with feature engineering, was developed and evaluated for spectrum analysis, significantly enhancing the prediction of mycotoxin concentrations. This approach extended the detection limit determined by the conventional method (∼72 ppb with high variation) to a wider range of 10 ppb to 100 ppm with high accuracy (overall mean absolute percentage error of 5.7%). The developed analytical tool provides a promising solution for detecting small molecules and monitoring chemical hazards in agri-food systems and the environment.
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