Pub Date : 2022-12-07DOI: 10.3389/fsens.2022.1080020
Edward Luy, James Smith, Iain Grundke, C. Sonnichsen, A. Furlong, V. Sieben
Autonomous in situ sensors are required to monitor high-frequency nutrient fluctuations in marine environments on a mass-scale. We present a submersible, dual-chemistry sensor that performs multiple colourimetric assays simultaneously on a fluid sample for multi-parameter in situ analysis. Based on a highly configurable architecture that has been successfully deployed for several multi-month periods, the sensor utilizes 10 solenoid valves, 4 syringes, 3 stepper motors, 2 LEDs, 4 photodiodes, and “inlaid” microfluidics to permit optical measurements of microliter fluid volumes. Fluid pathways are machined into a modular two-layer microfluidic lab-on-chip (LOC) fabricated from poly (methyl methacrylate) (PMMA) with two parallel inlaid optical cells of 10.4 mm and 25.4 mm path lengths (1.7 µl and 4 μl, respectively). Different LOC designs can be used to implement a wide variety of colorimetric assays. We demonstrate application of our dual-chemistry sensor towards simultaneous measurement of nitrate and dissolved orthophosphate: two nutrients fundamental to primary production. The performance of the dual-species nitrate and phosphate “NP Sensor” is characterized first in a controlled laboratory environment. Combined nutrient standards containing nitrate and phosphate concentrations ranging from 2.5 µM–100 µM N O 3 − and 0.25 µM–10 µM P O 4 3 − were analyzed, reporting detection limits of 97 nM N O 3 − and 15 nM P O 4 3 − . Calibrations were repeated under 3 fixed temperature conditions, T = 5°C, 10°C, 15°C, to determine the temperature-dependent sensitivity relations for both species needed to calculate concentrations during field deployments. Finally, an 8-day field deployment in Fish Hatchery Park, NS, Canada followed, acquiring a total of 592 nitrate and dissolved orthophosphate measurements. An on-board combined nutrient standard was measured periodically to assess the in situ accuracy of the sensor, with an average relative uncertainty of 15% across the deployment. Measured nitrate and dissolved orthophosphate levels in the river reached as high as 10 µM and 3.6 µM, respectively. Fast Fourier transform analysis suggests a strong out-of-phase relationship between measured phosphate and water level, with a shared frequency peak in both data agreeing within a 3.2% difference. This trend is due to conventional mixing at the river mouth to neighboring Bedford Basin. A spike in the measured nitrate to phosphate (N:P) ratio was also observed, synchronized to a precipitation event and indicative of runoff. The novel sensor will enable high-frequency dual-nutrient monitoring in many aquatic environments. Graphical Abstract
需要自主的原位传感器来大规模监测海洋环境中的高频营养物质波动。我们提出了一种潜水式双化学传感器，它可以对流体样品同时进行多种色度测定，用于多参数原位分析。基于已成功部署数个月的高度可配置架构，该传感器利用10个电磁阀、4个注射器、3个步进电机、2个LED、4个光电二极管和“嵌入式”微流体，实现微升流体体积的光学测量。流体通道被加工成模块化的两层微流体芯片实验室（LOC），该实验室由聚甲基丙烯酸甲酯（PMMA）制成，具有两个平行镶嵌的光学单元，路径长度分别为10.4 mm和25.4 mm（分别为1.7µl和4μl）。不同的LOC设计可用于实施各种各样的比色测定。我们展示了我们的双化学传感器在同时测量硝酸盐和溶解的正磷酸盐方面的应用：这两种营养素是初级生产的基础。硝酸盐和磷酸盐双物种“NP传感器”的性能首先在受控的实验室环境中进行了表征。分析了硝酸盐和磷酸盐浓度范围为2.5µM–100µM N O 3−和0.25µM–10µM P O 4 3−的联合营养标准品，报告检测限为97 nM N O 3–和15 nM P O 3−。在T=5°C、10°C、15°C的3个固定温度条件下重复校准，以确定两种物种在野外部署期间计算浓度所需的温度相关灵敏度关系。最后，在加拿大NS的Fish Hatchery Park进行了为期8天的实地部署，共获得592份硝酸盐和溶解正磷酸盐测量结果。定期测量机载组合营养素标准，以评估传感器的原位精度，整个部署的平均相对不确定度为15%。河流中的硝酸盐和溶解正磷酸盐含量分别高达10µM和3.6µM。快速傅立叶变换分析表明，测得的磷酸盐和水位之间存在强烈的异相关系，两个数据中的共享频率峰值相差3.2%。这一趋势是由于河口到邻近贝德福德盆地的传统混合造成的。还观察到测得的硝酸盐与磷酸盐（N:P）的比值出现峰值，与降水事件同步，表明径流。这种新型传感器将能够在许多水生环境中进行高频双营养监测。图形摘要
{"title":"Two chemistries on a single lab-on-chip: Nitrate and orthophosphate sensing underwater with inlaid microfluidics","authors":"Edward Luy, James Smith, Iain Grundke, C. Sonnichsen, A. Furlong, V. Sieben","doi":"10.3389/fsens.2022.1080020","DOIUrl":"https://doi.org/10.3389/fsens.2022.1080020","url":null,"abstract":"Autonomous in situ sensors are required to monitor high-frequency nutrient fluctuations in marine environments on a mass-scale. We present a submersible, dual-chemistry sensor that performs multiple colourimetric assays simultaneously on a fluid sample for multi-parameter in situ analysis. Based on a highly configurable architecture that has been successfully deployed for several multi-month periods, the sensor utilizes 10 solenoid valves, 4 syringes, 3 stepper motors, 2 LEDs, 4 photodiodes, and “inlaid” microfluidics to permit optical measurements of microliter fluid volumes. Fluid pathways are machined into a modular two-layer microfluidic lab-on-chip (LOC) fabricated from poly (methyl methacrylate) (PMMA) with two parallel inlaid optical cells of 10.4 mm and 25.4 mm path lengths (1.7 µl and 4 μl, respectively). Different LOC designs can be used to implement a wide variety of colorimetric assays. We demonstrate application of our dual-chemistry sensor towards simultaneous measurement of nitrate and dissolved orthophosphate: two nutrients fundamental to primary production. The performance of the dual-species nitrate and phosphate “NP Sensor” is characterized first in a controlled laboratory environment. Combined nutrient standards containing nitrate and phosphate concentrations ranging from 2.5 µM–100 µM N O 3 − and 0.25 µM–10 µM P O 4 3 − were analyzed, reporting detection limits of 97 nM N O 3 − and 15 nM P O 4 3 − . Calibrations were repeated under 3 fixed temperature conditions, T = 5°C, 10°C, 15°C, to determine the temperature-dependent sensitivity relations for both species needed to calculate concentrations during field deployments. Finally, an 8-day field deployment in Fish Hatchery Park, NS, Canada followed, acquiring a total of 592 nitrate and dissolved orthophosphate measurements. An on-board combined nutrient standard was measured periodically to assess the in situ accuracy of the sensor, with an average relative uncertainty of 15% across the deployment. Measured nitrate and dissolved orthophosphate levels in the river reached as high as 10 µM and 3.6 µM, respectively. Fast Fourier transform analysis suggests a strong out-of-phase relationship between measured phosphate and water level, with a shared frequency peak in both data agreeing within a 3.2% difference. This trend is due to conventional mixing at the river mouth to neighboring Bedford Basin. A spike in the measured nitrate to phosphate (N:P) ratio was also observed, synchronized to a precipitation event and indicative of runoff. The novel sensor will enable high-frequency dual-nutrient monitoring in many aquatic environments. Graphical Abstract","PeriodicalId":93754,"journal":{"name":"Frontiers in sensors","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49117914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-11-22DOI: 10.3389/fsens.2022.1066974
Seungmin Lee, Jinhwan Kim, Nalae Lee, Kang-Hyeon Kim, Seong Jun Park, J. Park, Cheonjung Kim, Ji Hye Hong, D. Yoon, Y. Yoo, Jeong-Hoon Lee
A sample preconcentration technique that exceeds a microfluidic device’s limited processing volume (up to microliters) is critical for real sample pretreatment applications. Here, we have developed a 3D-printed preconcentrator with a pillar structure (3DP2) to enrich the biological samples up to hundreds of microliter scales (700 μL) within 20 min by utilizing ion concentration polarization (ICP). We designed three-dimensional ready-to-pick reservoirs serially connected with a pillar-structured channel to enable large-volume preconcentration by balancing the preconcentrating forces (depletion, electrophoretic, and electroosmotic force) generated by ICP. Using the I-t and I-V curves, we confirmed that ICP performance was enhanced due to a pillar structure’s suppression of the vortex. Finally, we preconcentrated bovine serum albumin (BSA) and micro ribonucleic acid-21 (miRNA-21) two-fold. Moreover, depending on their size and charge, these were concentrated at different locations and could be extracted easily using pipettes. We believe that this study provides a novel strategy for downstream applications.
{"title":"Three-dimensional ready-to-pick reservoir-based preconcentrator with a pillar-structured channel for miRNA applications","authors":"Seungmin Lee, Jinhwan Kim, Nalae Lee, Kang-Hyeon Kim, Seong Jun Park, J. Park, Cheonjung Kim, Ji Hye Hong, D. Yoon, Y. Yoo, Jeong-Hoon Lee","doi":"10.3389/fsens.2022.1066974","DOIUrl":"https://doi.org/10.3389/fsens.2022.1066974","url":null,"abstract":"A sample preconcentration technique that exceeds a microfluidic device’s limited processing volume (up to microliters) is critical for real sample pretreatment applications. Here, we have developed a 3D-printed preconcentrator with a pillar structure (3DP2) to enrich the biological samples up to hundreds of microliter scales (700 μL) within 20 min by utilizing ion concentration polarization (ICP). We designed three-dimensional ready-to-pick reservoirs serially connected with a pillar-structured channel to enable large-volume preconcentration by balancing the preconcentrating forces (depletion, electrophoretic, and electroosmotic force) generated by ICP. Using the I-t and I-V curves, we confirmed that ICP performance was enhanced due to a pillar structure’s suppression of the vortex. Finally, we preconcentrated bovine serum albumin (BSA) and micro ribonucleic acid-21 (miRNA-21) two-fold. Moreover, depending on their size and charge, these were concentrated at different locations and could be extracted easily using pipettes. We believe that this study provides a novel strategy for downstream applications.","PeriodicalId":93754,"journal":{"name":"Frontiers in sensors","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44830425","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-11-18DOI: 10.3389/fsens.2022.1040542
Sneha Daradmare, Jae Seong Kim, R. Ganguly, Chang-Soo Lee
Hydrogel capsules synthesized by conventional water-in-oil emulsion systems are the less preferred choice for biomedical applications due to the use of oils and surfactants. An aqueous two-phase system (ATPS), which allows the formation of water-in-water emulsion, is considered a green alternative and therefore has been explored a lot for its application in the biomedical field. Herein, we present the synthesis of hydrogel capsules using a set-up consisting of a pneumatic valve integrated with the ATPS microfluidic system. In this arrangement, at first, a pneumatic valve facilitates the generation of the droplets of one aqueous system i.e. sodium alginate (SA) containing dextran solution into another aqueous phase comprising polyethylene glycol solution. The present approach allows good control over droplet generation by tuning the pressure of the pneumatic valve and the flow rates of the core and middle phases. The synthesis of hybrid capsules within the microfluidic device is carried out mainly by using the interfacial complexation of oppositely charged polyelectrolytes, chitosan with SA via electrostatic interactions. The interfacial complexed SA and chitosan hydrogel capsules were collected via the settling collection method, which ensures the retaining of the shape of the hybrid capsules. The morphological properties of as-synthesized droplets and hybrid capsules were examined via optical microscopy. The hydrogel capsules show good encapsulation capability for the magnetic particles. Even though this study mainly focuses on the synthesis part, we anticipate that the proposed approach will enable the encapsulation of cells within the hybrid capsules as well as enhance the cell adhesion on the surface of the hydrogel capsules hence, these hydrogel capsules can find the potent application in the biomedical engineering.
{"title":"One-step on-chip microfluidic synthesis of the hybrid capsules using aqueous two-phase system","authors":"Sneha Daradmare, Jae Seong Kim, R. Ganguly, Chang-Soo Lee","doi":"10.3389/fsens.2022.1040542","DOIUrl":"https://doi.org/10.3389/fsens.2022.1040542","url":null,"abstract":"Hydrogel capsules synthesized by conventional water-in-oil emulsion systems are the less preferred choice for biomedical applications due to the use of oils and surfactants. An aqueous two-phase system (ATPS), which allows the formation of water-in-water emulsion, is considered a green alternative and therefore has been explored a lot for its application in the biomedical field. Herein, we present the synthesis of hydrogel capsules using a set-up consisting of a pneumatic valve integrated with the ATPS microfluidic system. In this arrangement, at first, a pneumatic valve facilitates the generation of the droplets of one aqueous system i.e. sodium alginate (SA) containing dextran solution into another aqueous phase comprising polyethylene glycol solution. The present approach allows good control over droplet generation by tuning the pressure of the pneumatic valve and the flow rates of the core and middle phases. The synthesis of hybrid capsules within the microfluidic device is carried out mainly by using the interfacial complexation of oppositely charged polyelectrolytes, chitosan with SA via electrostatic interactions. The interfacial complexed SA and chitosan hydrogel capsules were collected via the settling collection method, which ensures the retaining of the shape of the hybrid capsules. The morphological properties of as-synthesized droplets and hybrid capsules were examined via optical microscopy. The hydrogel capsules show good encapsulation capability for the magnetic particles. Even though this study mainly focuses on the synthesis part, we anticipate that the proposed approach will enable the encapsulation of cells within the hybrid capsules as well as enhance the cell adhesion on the surface of the hydrogel capsules hence, these hydrogel capsules can find the potent application in the biomedical engineering.","PeriodicalId":93754,"journal":{"name":"Frontiers in sensors","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47225606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-11-16DOI: 10.3389/fsens.2023.1102176
A. Harvie, J. D. de Mello
The Open Lock-In Amplifier (OLIA) is a microcontroller-based digital lock-in amplifier built from a small number of inexpensive and easily sourced electronic components. Despite its small credit card-sized form-factor and low build-cost of around US$35, OLIA is a capable instrument that offers many features associated with far costlier commercial devices. Key features include dual-phase lock-in detection at multiple harmonic frequencies up to 50 kHz, internal and external reference modes, adjustable levels of input gain, a choice between low-pass filtering and synchronous filtering, noise estimation, and a comprehensive programming interface for remote software control. OLIA comes with an optional optical breakout board that allows noise-tolerant optical detection down to the 40-pW level. OLIA and its breakout board are released here as open hardware, with technical diagrams, full parts-lists, and source-code for the firmware.
{"title":"OLIA: An open-source digital lock-in amplifier","authors":"A. Harvie, J. D. de Mello","doi":"10.3389/fsens.2023.1102176","DOIUrl":"https://doi.org/10.3389/fsens.2023.1102176","url":null,"abstract":"The Open Lock-In Amplifier (OLIA) is a microcontroller-based digital lock-in amplifier built from a small number of inexpensive and easily sourced electronic components. Despite its small credit card-sized form-factor and low build-cost of around US$35, OLIA is a capable instrument that offers many features associated with far costlier commercial devices. Key features include dual-phase lock-in detection at multiple harmonic frequencies up to 50 kHz, internal and external reference modes, adjustable levels of input gain, a choice between low-pass filtering and synchronous filtering, noise estimation, and a comprehensive programming interface for remote software control. OLIA comes with an optional optical breakout board that allows noise-tolerant optical detection down to the 40-pW level. OLIA and its breakout board are released here as open hardware, with technical diagrams, full parts-lists, and source-code for the firmware.","PeriodicalId":93754,"journal":{"name":"Frontiers in sensors","volume":"4 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48025038","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-11-03DOI: 10.3389/fsens.2022.1020202
Chanthujan Chandrakumar, R. Prasanna, M. Stephens, M. L. Tan
Earthquake early warning system (EEWS) plays an important role in detecting ground shaking during an earthquake and alerting the public and authorities to take appropriate safety measures, reducing possible damages to lives and property. However, the cost of high-end ground motion sensors makes most earthquake-prone countries unable to afford an EEWS. Low-cost Microelectromechanical systems (MEMS)-based ground motion sensors are becoming a promising solution for constructing an affordable yet reliable and robust EEWS. This paper contributes to advancing Earthquake early warning (EEW) research by conducting a literature review investigating different methods and approaches to building a low-cost EEWS using MEMS-based sensors in different territories. The review of 59 articles found that low-cost MEMS-based EEWSs can become a feasible solution for generating reliable and accurate EEW, especially for developing countries and can serve as a support system for high-end EEWS in terms of increasing the density of the sensors. Also, this paper proposes a classification for EEWSs based on the warning type and the EEW algorithm adopted. Further, with the support of the proposed EEWS classification, it summarises the different approaches researchers attempted in developing an EEWS. Following that, this paper discusses the challenges and complexities in implementing and maintaining a low-cost MEMS-based EEWS and proposes future research areas to improve the performance of EEWSs mainly in 1) exploring node-level processing, 2) introducing multi-sensor support capability, and 3) adopting ground motion-based EEW algorithms for generating EEW.
{"title":"Earthquake early warning systems based on low-cost ground motion sensors: A systematic literature review","authors":"Chanthujan Chandrakumar, R. Prasanna, M. Stephens, M. L. Tan","doi":"10.3389/fsens.2022.1020202","DOIUrl":"https://doi.org/10.3389/fsens.2022.1020202","url":null,"abstract":"Earthquake early warning system (EEWS) plays an important role in detecting ground shaking during an earthquake and alerting the public and authorities to take appropriate safety measures, reducing possible damages to lives and property. However, the cost of high-end ground motion sensors makes most earthquake-prone countries unable to afford an EEWS. Low-cost Microelectromechanical systems (MEMS)-based ground motion sensors are becoming a promising solution for constructing an affordable yet reliable and robust EEWS. This paper contributes to advancing Earthquake early warning (EEW) research by conducting a literature review investigating different methods and approaches to building a low-cost EEWS using MEMS-based sensors in different territories. The review of 59 articles found that low-cost MEMS-based EEWSs can become a feasible solution for generating reliable and accurate EEW, especially for developing countries and can serve as a support system for high-end EEWS in terms of increasing the density of the sensors. Also, this paper proposes a classification for EEWSs based on the warning type and the EEW algorithm adopted. Further, with the support of the proposed EEWS classification, it summarises the different approaches researchers attempted in developing an EEWS. Following that, this paper discusses the challenges and complexities in implementing and maintaining a low-cost MEMS-based EEWS and proposes future research areas to improve the performance of EEWSs mainly in 1) exploring node-level processing, 2) introducing multi-sensor support capability, and 3) adopting ground motion-based EEW algorithms for generating EEW.","PeriodicalId":93754,"journal":{"name":"Frontiers in sensors","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43883172","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-11-02DOI: 10.3389/fsens.2022.1015223
Likun Zhang, Zhengyang Lei, Chufan Xiao, Zhicheng Du, Chenyao Jiang, Xi Yuan, Qiuyue Hu, Shiyao Zhai, Lulu Xu, Changyue Liu, Xiao-Yu Zhong, Haifei Guan, Muhammad Hassan, I. Gul, V. Pandey, Xinhui Xing, Canyang Zhang, Qian He, Peiwu Qin
Integrating artificial intelligence with SARS-CoV-2 diagnostics can help in the timely execution of pandemic control and monitoring plans. To improve the efficiency of the diagnostic process, this study aims to classify fluorescent images via traditional machine learning and deep learning-based transfer learning. A previous study reported a CRISPR-Cas13a system combined with total internal reflection fluorescence microscopy (TIRFM) to detect the existence and concentrations of SARS-CoV-2 by fluorescent images. However, the lack of professional software and excessive manual labor hinder the practicability of the system. Here, we construct a fluorescent image dataset and develop an AI-boosted CRISPR-Cas13a and total internal reflection fluorescence microscopy system for the rapid diagnosis of SARS-CoV-2. Our study proposes Fluorescent Images Classification Transfer learning based on DenseNet-121 (FICTransDense), an approach that uses TIRF images (before and after sample introduction, respectively) for preprocessing, including outlier exclusion and setting and division preprocessing (i.e., SDP). Classification results indicate that the FICTransDense and Decision Tree algorithms outperform other approaches on the SDP dataset. Most of the algorithms benefit from the proposed SDP technique in terms of Accuracy, Recall, F1 Score, and Precision. The use of AI-boosted CRISPR-Cas13a and TIRFM systems facilitates rapid monitoring and diagnosis of SARS-CoV-2.
{"title":"AI-boosted CRISPR-Cas13a and total internal reflection fluorescence microscopy system for SARS-CoV-2 detection","authors":"Likun Zhang, Zhengyang Lei, Chufan Xiao, Zhicheng Du, Chenyao Jiang, Xi Yuan, Qiuyue Hu, Shiyao Zhai, Lulu Xu, Changyue Liu, Xiao-Yu Zhong, Haifei Guan, Muhammad Hassan, I. Gul, V. Pandey, Xinhui Xing, Canyang Zhang, Qian He, Peiwu Qin","doi":"10.3389/fsens.2022.1015223","DOIUrl":"https://doi.org/10.3389/fsens.2022.1015223","url":null,"abstract":"Integrating artificial intelligence with SARS-CoV-2 diagnostics can help in the timely execution of pandemic control and monitoring plans. To improve the efficiency of the diagnostic process, this study aims to classify fluorescent images via traditional machine learning and deep learning-based transfer learning. A previous study reported a CRISPR-Cas13a system combined with total internal reflection fluorescence microscopy (TIRFM) to detect the existence and concentrations of SARS-CoV-2 by fluorescent images. However, the lack of professional software and excessive manual labor hinder the practicability of the system. Here, we construct a fluorescent image dataset and develop an AI-boosted CRISPR-Cas13a and total internal reflection fluorescence microscopy system for the rapid diagnosis of SARS-CoV-2. Our study proposes Fluorescent Images Classification Transfer learning based on DenseNet-121 (FICTransDense), an approach that uses TIRF images (before and after sample introduction, respectively) for preprocessing, including outlier exclusion and setting and division preprocessing (i.e., SDP). Classification results indicate that the FICTransDense and Decision Tree algorithms outperform other approaches on the SDP dataset. Most of the algorithms benefit from the proposed SDP technique in terms of Accuracy, Recall, F1 Score, and Precision. The use of AI-boosted CRISPR-Cas13a and TIRFM systems facilitates rapid monitoring and diagnosis of SARS-CoV-2.","PeriodicalId":93754,"journal":{"name":"Frontiers in sensors","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45352556","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-28DOI: 10.3389/fsens.2022.1012775
Youngkwang Moon, Hyeokgyun Moon, Junhyuck Chang, Harold D. Kim, Jung Heon Lee, Jinkee Lee
Extensive research is focused on the development of highly sensitive, rapid on-site diagnostic devices. The lateral flow strip (LFS) is a paper-based point-of-care diagnostic device, which is highly promising because of its ease of use and low cost. Despite these advantages, LFS device is still less popular than other methods such as enzyme-linked immunosorbent assay (ELISA) or real-time polymerase chain reaction (qPCR) due to its low sensitivity. Here, we have developed a fluorescence-based lateral flow strip (f-LFS) device for DNA detection using a molecular beacon (MB), a short hairpin-forming DNA strand tagged with a fluorophore-quencher pair. Each paper and membrane component of f-LFS device was carefully selected based on their physicochemical properties including porosity, surface functionality, and autofluorescence. The limit of detection (LOD) of this device was substantially improved to 2.1 fg/mL by adding MgCl2 to the reaction buffer and narrowing the test membrane dimension. Also, a portable fluorescence detection system for f-LFS was developed using a multi-pixel photon counter (MPPC), a sensitive detector detecting the signal on site. We anticipate that this highly sensitive paper-based diagnostic device can be utilized for on-site diagnosis of various diseases.
{"title":"Development of a highly sensitive lateral flow strip device for nucleic acid detection using molecular beacons","authors":"Youngkwang Moon, Hyeokgyun Moon, Junhyuck Chang, Harold D. Kim, Jung Heon Lee, Jinkee Lee","doi":"10.3389/fsens.2022.1012775","DOIUrl":"https://doi.org/10.3389/fsens.2022.1012775","url":null,"abstract":"Extensive research is focused on the development of highly sensitive, rapid on-site diagnostic devices. The lateral flow strip (LFS) is a paper-based point-of-care diagnostic device, which is highly promising because of its ease of use and low cost. Despite these advantages, LFS device is still less popular than other methods such as enzyme-linked immunosorbent assay (ELISA) or real-time polymerase chain reaction (qPCR) due to its low sensitivity. Here, we have developed a fluorescence-based lateral flow strip (f-LFS) device for DNA detection using a molecular beacon (MB), a short hairpin-forming DNA strand tagged with a fluorophore-quencher pair. Each paper and membrane component of f-LFS device was carefully selected based on their physicochemical properties including porosity, surface functionality, and autofluorescence. The limit of detection (LOD) of this device was substantially improved to 2.1 fg/mL by adding MgCl2 to the reaction buffer and narrowing the test membrane dimension. Also, a portable fluorescence detection system for f-LFS was developed using a multi-pixel photon counter (MPPC), a sensitive detector detecting the signal on site. We anticipate that this highly sensitive paper-based diagnostic device can be utilized for on-site diagnosis of various diseases.","PeriodicalId":93754,"journal":{"name":"Frontiers in sensors","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43302293","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-27DOI: 10.3389/fsens.2022.1006749
Sajjad Hajian, D. Maddipatla, B. B. Narakathu, M. Atashbar
MXenes are an emerging family of two-dimensional (2D) materials which exhibits unique characteristics such as metal-like thermal and electrical conductivity, huge surface area, biocompatibility, low toxicity, excellent electrochemical performance, remarkable chemical stability, antibacterial activity, and hydrophilicity. Initially, MXene materials were synthesized by selectively etching metal layers from MAX phases, layered transition metal carbides, and carbonitrides with hydrofluoric acid. Multiple novel synthesis methods have since been developed for the creation of MXenes with improved surface chemistries using non-aqueous etchants, molten salts, fluoride salts, and various acid halogens. Due to the promising potential of MXenes, they have emerged as attractive 2D materials with applications in various fields such as energy storage, sensing, and biomedical. This review provides a comprehensive overview of MXenes and discusses the synthesis and properties of MXenes, including the methods of etching, delamination, and modification/functionalization, as well as the electrical properties of MXenes. Following this, the recent advances in the development of various MXene-based sensors are presented. Finally, the challenges and opportunities for future research on the development of MXenes-based sensors are discussed.
{"title":"MXene-based flexible sensors: A review","authors":"Sajjad Hajian, D. Maddipatla, B. B. Narakathu, M. Atashbar","doi":"10.3389/fsens.2022.1006749","DOIUrl":"https://doi.org/10.3389/fsens.2022.1006749","url":null,"abstract":"MXenes are an emerging family of two-dimensional (2D) materials which exhibits unique characteristics such as metal-like thermal and electrical conductivity, huge surface area, biocompatibility, low toxicity, excellent electrochemical performance, remarkable chemical stability, antibacterial activity, and hydrophilicity. Initially, MXene materials were synthesized by selectively etching metal layers from MAX phases, layered transition metal carbides, and carbonitrides with hydrofluoric acid. Multiple novel synthesis methods have since been developed for the creation of MXenes with improved surface chemistries using non-aqueous etchants, molten salts, fluoride salts, and various acid halogens. Due to the promising potential of MXenes, they have emerged as attractive 2D materials with applications in various fields such as energy storage, sensing, and biomedical. This review provides a comprehensive overview of MXenes and discusses the synthesis and properties of MXenes, including the methods of etching, delamination, and modification/functionalization, as well as the electrical properties of MXenes. Following this, the recent advances in the development of various MXene-based sensors are presented. Finally, the challenges and opportunities for future research on the development of MXenes-based sensors are discussed.","PeriodicalId":93754,"journal":{"name":"Frontiers in sensors","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42189168","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-21DOI: 10.3389/fsens.2022.1014864
Adedamola D. Aladese, Heon-Ho Jeong
Droplet microfluidics, which is the manipulation and handling of fluid in microscale channels, has excellent applications in material science, chemical synthesis, genetic analysis, drug discovery and delivery, organ on chips, and tissue engineering. Consequently, this field has attracted significant attention from both academic institutions and industries. However, one of the major constraints is increasing the droplet production rate from a single generator to thousands of generators in order to move from a laboratory scale to industrial standards. Although the scale-up method (in this case, parallelization) of droplet production using theoretical calculations has been extensively investigated, it has been discovered to be occasionally unreliable during experiments. The use of computational fluid dynamics (CFD) simulation, which has recently been applied to droplet microfluidics, has helped to determine the exact factors and conditions required for uniform droplet formation in flow-focusing devices. Thus far, there has been limited study on the simulation of distribution structures that effectively supply fluids to microfluidic devices in parallel orientation. In this study, CFD is used to provide detailed insights into the conditions required to achieve uniform fluid distribution in the delivery and/or distribution channel of microfluidic devices, and experimental analysis is used to further validate the findings.
{"title":"Numerical and experimental investigations of uniform fluid distribution for droplet formation in parallelized microfluidics","authors":"Adedamola D. Aladese, Heon-Ho Jeong","doi":"10.3389/fsens.2022.1014864","DOIUrl":"https://doi.org/10.3389/fsens.2022.1014864","url":null,"abstract":"Droplet microfluidics, which is the manipulation and handling of fluid in microscale channels, has excellent applications in material science, chemical synthesis, genetic analysis, drug discovery and delivery, organ on chips, and tissue engineering. Consequently, this field has attracted significant attention from both academic institutions and industries. However, one of the major constraints is increasing the droplet production rate from a single generator to thousands of generators in order to move from a laboratory scale to industrial standards. Although the scale-up method (in this case, parallelization) of droplet production using theoretical calculations has been extensively investigated, it has been discovered to be occasionally unreliable during experiments. The use of computational fluid dynamics (CFD) simulation, which has recently been applied to droplet microfluidics, has helped to determine the exact factors and conditions required for uniform droplet formation in flow-focusing devices. Thus far, there has been limited study on the simulation of distribution structures that effectively supply fluids to microfluidic devices in parallel orientation. In this study, CFD is used to provide detailed insights into the conditions required to achieve uniform fluid distribution in the delivery and/or distribution channel of microfluidic devices, and experimental analysis is used to further validate the findings.","PeriodicalId":93754,"journal":{"name":"Frontiers in sensors","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47319723","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-10-18DOI: 10.3389/fsens.2022.1037723
Haoyue Zhang, Chengze Li, Yujie Zhang, Chuanfeng An, Hanting Li, Jiahui Yu, Yonghao Zhang, Wei He, Huanan Wang
Microfluidics-based fabrication of cell-laden microgels has shown great potential for applications in cell therapy and tissue engineering, however, the difficulty in chip operation and compromised cell viability due to cell sedimentation and channel blockage remain a major challenge for functional cell-laden microgels preparation. Herein, we presented the design and optimization of integrated microfluidic chip for large-scale preparation of cell-laden microgels with controllable size and complex microstructure. Specifically, to avoid severe cell sedimentation and uneven distribution in the parallelized microchannel, we simulated cell movement state using computational fluid dynamics simulation. It was found that higher laminar flow velocity gradient and higher precursor viscosity can significantly improve the uniform cell distribution in parallelized channels and reduce the product difference between channels. Moreover, we designed multiple-layered microfluidic chips allowing multiple inputting liquids for the fabrication of microgels with complex structures. This integrated chip facilitated cell encapsulation at a maximum production rate of 240 ml/h of cell suspension with retained cell viability and functionality. Therefore, our study provided a biocompatible and high-throughput strategy for large-scale preparation of cell-laden microgels, which can enable significant advances for clinical-relevant applications of cell-laden microgels, including cell therapy, tissue regeneration and 3D bioprinting.
{"title":"High-throughput generation of microfluidic-templating microgels for large-scale single-cell encapsulation","authors":"Haoyue Zhang, Chengze Li, Yujie Zhang, Chuanfeng An, Hanting Li, Jiahui Yu, Yonghao Zhang, Wei He, Huanan Wang","doi":"10.3389/fsens.2022.1037723","DOIUrl":"https://doi.org/10.3389/fsens.2022.1037723","url":null,"abstract":"Microfluidics-based fabrication of cell-laden microgels has shown great potential for applications in cell therapy and tissue engineering, however, the difficulty in chip operation and compromised cell viability due to cell sedimentation and channel blockage remain a major challenge for functional cell-laden microgels preparation. Herein, we presented the design and optimization of integrated microfluidic chip for large-scale preparation of cell-laden microgels with controllable size and complex microstructure. Specifically, to avoid severe cell sedimentation and uneven distribution in the parallelized microchannel, we simulated cell movement state using computational fluid dynamics simulation. It was found that higher laminar flow velocity gradient and higher precursor viscosity can significantly improve the uniform cell distribution in parallelized channels and reduce the product difference between channels. Moreover, we designed multiple-layered microfluidic chips allowing multiple inputting liquids for the fabrication of microgels with complex structures. This integrated chip facilitated cell encapsulation at a maximum production rate of 240 ml/h of cell suspension with retained cell viability and functionality. Therefore, our study provided a biocompatible and high-throughput strategy for large-scale preparation of cell-laden microgels, which can enable significant advances for clinical-relevant applications of cell-laden microgels, including cell therapy, tissue regeneration and 3D bioprinting.","PeriodicalId":93754,"journal":{"name":"Frontiers in sensors","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49397952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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