Microfluidic systems incorporating magnetic droplets have emerged as a focal point of significant interest within the biomedical domain. The allure of these systems lies in their capacity to offer precise control, enable contactless operation, and accommodate minimal sample concentration requirements. Such remarkable features serve to mitigate errors arising from human operation and other factors during cell or molecular detection. By providing innovative solutions for molecular diagnostics and immunoassay applications, magnetic droplet microfluidics enhance the accuracy and efficiency of these procedures. This review undertakes a comprehensive examination of the research progress in microfluidic systems centered around magnetic droplets. It adheres to a sequential presentation approach, commencing from the fundamental operation principles, specifically the generation of magnetic droplets on the microfluidic chip, and proceeding to their transmission and mixing within the microchannel via an array of operating techniques. Additionally, the relevant detection technologies associated with magnetic drop microfluidics and their numerous applications within the biomedical field are systematically classified and reviewed. The overarching objective of this review is to spotlight key advancements and offer valuable insights into the future trajectory of this burgeoning field.
{"title":"Generation, Manipulation, Detection and Biomedical Applications of Magnetic Droplets in Microfluidic Chips","authors":"Chenyang Xu, Huanhuan Shi, Zhongjian Tan, Yun Zheng, Weizheng Xu, Zhengxian Dan, Jiacong Liao, Zhiying Dai, Yali Zhao","doi":"10.1039/d4an01175a","DOIUrl":"https://doi.org/10.1039/d4an01175a","url":null,"abstract":"Microfluidic systems incorporating magnetic droplets have emerged as a focal point of significant interest within the biomedical domain. The allure of these systems lies in their capacity to offer precise control, enable contactless operation, and accommodate minimal sample concentration requirements. Such remarkable features serve to mitigate errors arising from human operation and other factors during cell or molecular detection. By providing innovative solutions for molecular diagnostics and immunoassay applications, magnetic droplet microfluidics enhance the accuracy and efficiency of these procedures. This review undertakes a comprehensive examination of the research progress in microfluidic systems centered around magnetic droplets. It adheres to a sequential presentation approach, commencing from the fundamental operation principles, specifically the generation of magnetic droplets on the microfluidic chip, and proceeding to their transmission and mixing within the microchannel via an array of operating techniques. Additionally, the relevant detection technologies associated with magnetic drop microfluidics and their numerous applications within the biomedical field are systematically classified and reviewed. The overarching objective of this review is to spotlight key advancements and offer valuable insights into the future trajectory of this burgeoning field.","PeriodicalId":63,"journal":{"name":"Analyst","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142486291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Oksana Bondar, Gamal A. I. Moustafa, Thomas Robertson
Signal Amplification By Reversible Exchange (SABRE) can provide strong signal enhancement (SE) to an array of molecules through reversible exchange of parahydrogen (pH2) derived hydrides and a suitable substrate coordinated to a transition metal. Among the substrates that can be used as a probe for hyperpolarised NMR and MRI, pyruvate has gained much attention. SABRE can hyperpolarise pyruvate in a low cost, fast, and reversible fashion that does not involve technologically demanding equipment. Most SABRE polarization studies have been done using methanol-d4 as a solvent, which is not suitable for in vivo application. The main goal of this work was to obtain hyperpolarized pyruvate in a solvent other then methanol which may open the door to further purification steps and enable a method to polarize pyruvate in water in future. This work demonstrates hyperpolarization of the [2-13C]pyruvate as well as [1-13C]pyruvate by SABRE in an acetone/water solvent system at room temperature as an alternative to methanol, which is commonly used. NMR signals are detected using a 1.1 T benchtop NMR spectrometer. In this work we have primarily focused on the study of [2-13C]pyruvate and investigated the effect of catalyst concentration, DMSO presence and water vs acetone solvent concentration on the signal enhancement. The relaxation times for [2-13C]-pyruvate solutions are reported in the hope of informing the development of future purification methods.
{"title":"Hyperpolarised [2-13C]-pyruvate by [2-13C] SABRE in an acetone/water mixture","authors":"Oksana Bondar, Gamal A. I. Moustafa, Thomas Robertson","doi":"10.1039/d4an01005a","DOIUrl":"https://doi.org/10.1039/d4an01005a","url":null,"abstract":"Signal Amplification By Reversible Exchange (SABRE) can provide strong signal enhancement (SE) to an array of molecules through reversible exchange of parahydrogen (pH<small><sub>2</sub></small>) derived hydrides and a suitable substrate coordinated to a transition metal. Among the substrates that can be used as a probe for hyperpolarised NMR and MRI, pyruvate has gained much attention. SABRE can hyperpolarise pyruvate in a low cost, fast, and reversible fashion that does not involve technologically demanding equipment. Most SABRE polarization studies have been done using methanol-d<small><sub>4</sub></small> as a solvent, which is not suitable for in vivo application. The main goal of this work was to obtain hyperpolarized pyruvate in a solvent other then methanol which may open the door to further purification steps and enable a method to polarize pyruvate in water in future. This work demonstrates hyperpolarization of the [2-<small><sup>13</sup></small>C]pyruvate as well as [1-<small><sup>13</sup></small>C]pyruvate by SABRE in an acetone/water solvent system at room temperature as an alternative to methanol, which is commonly used. NMR signals are detected using a 1.1 T benchtop NMR spectrometer. In this work we have primarily focused on the study of [2-<small><sup>13</sup></small>C]pyruvate and investigated the effect of catalyst concentration, DMSO presence and water vs acetone solvent concentration on the signal enhancement. The relaxation times for [2-<small><sup>13</sup></small>C]-pyruvate solutions are reported in the hope of informing the development of future purification methods.","PeriodicalId":63,"journal":{"name":"Analyst","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142452013","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Feng-yan Kuang, De-jun Hu, Lu Wang, Fei Chen, Guang-Ping Lv
The selection of matrix is crucial for matrix assisted laser desorption ionization mass spectrometry imaging (MALDI MSI). This work successfully synthesized metal-organic frameworks (MOFs) matrices to address the limitations of the application of traditional organic matrices in the study of small molecule compositions, and Ti-based MOF nanosheets were screened as matrices for imaging the hepatotoxic components of Polygonum multiflorum. The comparison between six MOF materials and traditional organic matrices showed that Ti-based MOF nanosheets have less background interference, significant stability, and high salt resistance. The imaging results indicated that the main components of Polygonum multiflorum, free anthraquinone and stilbene glycoside, have unique spatial distribution characteristics. The successful application of the synthesized Ti-based MOF nanosheets in mass spectrometry imaging improved the detection ability of mass spectrometry imaging in the small molecule field, and the spatiotemporal content changes of hepatotoxic components in Polygonum multiflorum during the steaming process were observed, providing scientific basis for steaming.
基质的选择对于基质辅助激光解吸电离质谱成像（MALDI MSI）至关重要。针对传统有机基质在小分子成分研究中应用的局限性，本研究成功合成了金属有机框架（MOFs）基质，并筛选出Ti基MOF纳米片作为何首乌肝毒性成分成像的基质。六种 MOF 材料与传统有机基质的比较结果表明，钛基 MOF 纳米片背景干扰小、稳定性好、耐盐性高。成像结果表明，何首乌的主要成分游离蒽醌和二苯乙烯苷具有独特的空间分布特征。合成的 Ti 基 MOF 纳米片在质谱成像中的成功应用，提高了质谱成像在小分子领域的检测能力，并观察到蒸制过程中何首乌中肝毒成分的时空含量变化，为蒸制提供了科学依据。
{"title":"Ti-based MOF nanosheets as a mass spectrometry imaging matrix for low molecular weight compounds to reveal the spatiotemporal content changes of hepatotoxic components during the processing of Polygonum multiflorum","authors":"Feng-yan Kuang, De-jun Hu, Lu Wang, Fei Chen, Guang-Ping Lv","doi":"10.1039/d4an00964a","DOIUrl":"https://doi.org/10.1039/d4an00964a","url":null,"abstract":"The selection of matrix is crucial for matrix assisted laser desorption ionization mass spectrometry imaging (MALDI MSI). This work successfully synthesized metal-organic frameworks (MOFs) matrices to address the limitations of the application of traditional organic matrices in the study of small molecule compositions, and Ti-based MOF nanosheets were screened as matrices for imaging the hepatotoxic components of Polygonum multiflorum. The comparison between six MOF materials and traditional organic matrices showed that Ti-based MOF nanosheets have less background interference, significant stability, and high salt resistance. The imaging results indicated that the main components of Polygonum multiflorum, free anthraquinone and stilbene glycoside, have unique spatial distribution characteristics. The successful application of the synthesized Ti-based MOF nanosheets in mass spectrometry imaging improved the detection ability of mass spectrometry imaging in the small molecule field, and the spatiotemporal content changes of hepatotoxic components in Polygonum multiflorum during the steaming process were observed, providing scientific basis for steaming.","PeriodicalId":63,"journal":{"name":"Analyst","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142452411","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
With greater population density, the likelihood of viral outbreaks achieving pandemic status is increasing. However, current viral screening techniques use specific reagents, and as viruses mutate, test accuracy decreases. Here, we present the first real-time, reagent-free, portable analysis platform for viral detection in liquid saliva, using COVID-19 as a proof-of-concept. We show that vibrational molecular spectroscopy and machine learning (ML) detect biomolecular changes consistent with the presence of viral infection. Saliva samples were collected from 470 individuals, including 65 that were infected with COVID-19 (38 from hospitalized patients and 37 from a walk-in testing clinic) and 251 that had a negative polymerase chain reaction (PCR) test. A further 154 were collected from healthy volunteers. Saliva measurements were achieved in 6 minutes or less and led to machine learning models predicting COVID-19 infection with sensitivity and specificity reaching 90%, depending on volunteer symptoms and disease severity. Machine learning models were based on linear support vector machines (SVM). This platform could be deployed to manage future pandemics using the same hardware but using a tunable machine learning model that could be rapidly updated as new viral strains emerge.
{"title":"Liquid saliva-based Raman spectroscopy device with on-board machine learning detects COVID-19 infection in real-time","authors":"Katherine Ember, Nassim Ksantini, Frédérick Dallaire, Guillaume Sheehy, Trang Tran, Mathieu Dehaes, Madeleine Duran, Dominique Trudel, Frederic Leblond","doi":"10.1039/d4an00729h","DOIUrl":"https://doi.org/10.1039/d4an00729h","url":null,"abstract":"With greater population density, the likelihood of viral outbreaks achieving pandemic status is increasing. However, current viral screening techniques use specific reagents, and as viruses mutate, test accuracy decreases. Here, we present the first real-time, reagent-free, portable analysis platform for viral detection in liquid saliva, using COVID-19 as a proof-of-concept. We show that vibrational molecular spectroscopy and machine learning (ML) detect biomolecular changes consistent with the presence of viral infection. Saliva samples were collected from 470 individuals, including 65 that were infected with COVID-19 (38 from hospitalized patients and 37 from a walk-in testing clinic) and 251 that had a negative polymerase chain reaction (PCR) test. A further 154 were collected from healthy volunteers. Saliva measurements were achieved in 6 minutes or less and led to machine learning models predicting COVID-19 infection with sensitivity and specificity reaching 90%, depending on volunteer symptoms and disease severity. Machine learning models were based on linear support vector machines (SVM). This platform could be deployed to manage future pandemics using the same hardware but using a tunable machine learning model that could be rapidly updated as new viral strains emerge.","PeriodicalId":63,"journal":{"name":"Analyst","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142452410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Maria Nikitina, Pavel Khramtsov, Stepan Devyatov, Rishat G. Valeev, Marina Eremina, Andrey Chukavin, Mikhail Rayev
LaNiO3 perovskite nanoparticles, especially nanospheres (LNNS), show great promise in biomedical assays due to their peroxidase-like catalytic properties. However, LNNS-based diagnostic reagents have not been tested in nanozyme enzyme-linked immunosorbent assay (NLISA) or other enzyme-linked immunosorbent assays, and there is limited data on their synthesis. To fill this gap, it is necessary to develop a method for creating LNNS conjugates with monoclonal antibodies and to investigate the reproducibility, scalability, and applicability of these diagnostic reagents in NLISA. We have successfully developed a method for producing novel diagnostic reagents utilizing LaNiO3 nanospheres. Our research demonstrates the application of these nanospheres in a NLISA specifically designed for the detection of C-reactive protein (CRP) in real serum samples. This method is both reproducible and scalable, allowing for the efficient production of nanospheres that are functionalized with monoclonal antibodies targeting CRP, with mean diameter of approximately 270 nm. Based on the promising results obtained from our experiments, we have developed and optimized a sandwich-format NLISA for CRP detection. This assay achieved lower limit of detection at 0.178 µg/L, with a dynamic range from 12.5 to 0.195 µg/L and a linear detection range extending from 0.195 to 6.25 µg/L, showcasing its potential for clinical applications. The new NLISA method, utilizing LaNiO3 nanospheres in a sandwich format for the detection of CRP, significantly enhances sensitivity compared to similar use horseradish peroxidase-based -ELISA. In this study for the first time first the functionalization of lanthanum nickelate nanospheres with recognition elements have demonstrated. This advancement also sheds light on the technological challenges involved in synthesizing diagnostic reagents, identifying areas that need further exploration.
{"title":"The development of a method to produce diagnostic reagents using LaNiO3 nanospheres and their application in nanozyme-linked immunosorbent assay for the colorimetric screening of C-reactive protein with high sensitivity","authors":"Maria Nikitina, Pavel Khramtsov, Stepan Devyatov, Rishat G. Valeev, Marina Eremina, Andrey Chukavin, Mikhail Rayev","doi":"10.1039/d4an01160k","DOIUrl":"https://doi.org/10.1039/d4an01160k","url":null,"abstract":"LaNiO3 perovskite nanoparticles, especially nanospheres (LNNS), show great promise in biomedical assays due to their peroxidase-like catalytic properties. However, LNNS-based diagnostic reagents have not been tested in nanozyme enzyme-linked immunosorbent assay (NLISA) or other enzyme-linked immunosorbent assays, and there is limited data on their synthesis. To fill this gap, it is necessary to develop a method for creating LNNS conjugates with monoclonal antibodies and to investigate the reproducibility, scalability, and applicability of these diagnostic reagents in NLISA. We have successfully developed a method for producing novel diagnostic reagents utilizing LaNiO3 nanospheres. Our research demonstrates the application of these nanospheres in a NLISA specifically designed for the detection of C-reactive protein (CRP) in real serum samples. This method is both reproducible and scalable, allowing for the efficient production of nanospheres that are functionalized with monoclonal antibodies targeting CRP, with mean diameter of approximately 270 nm. Based on the promising results obtained from our experiments, we have developed and optimized a sandwich-format NLISA for CRP detection. This assay achieved lower limit of detection at 0.178 µg/L, with a dynamic range from 12.5 to 0.195 µg/L and a linear detection range extending from 0.195 to 6.25 µg/L, showcasing its potential for clinical applications. The new NLISA method, utilizing LaNiO3 nanospheres in a sandwich format for the detection of CRP, significantly enhances sensitivity compared to similar use horseradish peroxidase-based -ELISA. In this study for the first time first the functionalization of lanthanum nickelate nanospheres with recognition elements have demonstrated. This advancement also sheds light on the technological challenges involved in synthesizing diagnostic reagents, identifying areas that need further exploration.","PeriodicalId":63,"journal":{"name":"Analyst","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142452015","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this article, we present the first demonstration of a distance-based paper analytical device (dPAD) for uric acid quantification in human urine samples with instrument-free readout and user-friendliness for the rapid diagnosis and prognosis of various related diseases. By employing gold nanoparticles (AuNPs) as a peroxidase-like nanozyme, our proposed technique eliminates the utilization of horseradish peroxidase (HRP), making the device cost-effective and stable. In our dPAD, uric acid in the sample is oxidized by the uricase enzyme and subsequently catalysed with AuNPs in the sample zone, generating hydroxyl radicals (˙OH). Then, the produced ˙OH reacts with 3,3′-diaminobenzidine (DAB) to form poly DAB (oxDAB), resulting in a coloured distance signal in the detection zone of the dPAD. The variation of the distance of the observed red-brown colour is directly proportional to the uric acid concentration. Our sensor exhibited a linear range from 0.50 to 6.0 mmol L−1 (R2 = 0.9922) with a detection limit (LOD) of 0.25 mmol L−1, covering the clinical range of uric acid in urine. Hence, there is no need for additional sample preparation or dilution. Additionally, this assay is highly selective, with no interferences. We also found that this approach could accurately and precisely determine uric acid in human control samples with the recovery ranging from 99.37 to 100.35 with the highest RSD of 4.05%. Our method is comparable with the use of a commercially available uric acid sensor at a 95% confidence interval. Consequently, the developed dPAD offers numerous advantages such as cost-effectiveness, simplicity, and ease of operation with unskilled individuals. Furthermore, this concept can be applied for extensive biosensing applications in monitoring other biomarkers as an alternative analytical point-of-care (POC) device.
{"title":"A gold nanomaterial-integrated distance-based analytical device for uric acid quantification in human urine samples","authors":"Tapparath Leelasattarathkul, Thithawat Trakoolwilaiwan, Kawin Khachornsakkul","doi":"10.1039/d4an01139b","DOIUrl":"https://doi.org/10.1039/d4an01139b","url":null,"abstract":"In this article, we present the first demonstration of a distance-based paper analytical device (dPAD) for uric acid quantification in human urine samples with instrument-free readout and user-friendliness for the rapid diagnosis and prognosis of various related diseases. By employing gold nanoparticles (AuNPs) as a peroxidase-like nanozyme, our proposed technique eliminates the utilization of horseradish peroxidase (HRP), making the device cost-effective and stable. In our dPAD, uric acid in the sample is oxidized by the uricase enzyme and subsequently catalysed with AuNPs in the sample zone, generating hydroxyl radicals (˙OH). Then, the produced ˙OH reacts with 3,3′-diaminobenzidine (DAB) to form poly DAB (oxDAB), resulting in a coloured distance signal in the detection zone of the dPAD. The variation of the distance of the observed red-brown colour is directly proportional to the uric acid concentration. Our sensor exhibited a linear range from 0.50 to 6.0 mmol L<small><sup>−1</sup></small> (<em>R</em><small><sup>2</sup></small> = 0.9922) with a detection limit (LOD) of 0.25 mmol L<small><sup>−1</sup></small>, covering the clinical range of uric acid in urine. Hence, there is no need for additional sample preparation or dilution. Additionally, this assay is highly selective, with no interferences. We also found that this approach could accurately and precisely determine uric acid in human control samples with the recovery ranging from 99.37 to 100.35 with the highest RSD of 4.05%. Our method is comparable with the use of a commercially available uric acid sensor at a 95% confidence interval. Consequently, the developed dPAD offers numerous advantages such as cost-effectiveness, simplicity, and ease of operation with unskilled individuals. Furthermore, this concept can be applied for extensive biosensing applications in monitoring other biomarkers as an alternative analytical point-of-care (POC) device.","PeriodicalId":63,"journal":{"name":"Analyst","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142448120","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The most common methodology for performing multiple chemical and biological reactions in parallel is to use microtitre plates with either manual or robotic dispensing of reactants and wash solutions. We envision a paradigm shift where acoustically levitated droplets serve as wells of microtitre plates and are acoustically manipulated to perform chemical and biological reactions in a non-contact fashion. This in turn requires that lines of droplets can be levitated and manipulated simultaneously so that same operations (merge, mix, and detect) can be performed on them in parallel. However, this has not been demonstrated until this work. Because of the nature of acoustic standing waves, a single focus has more than one trap, and can allow levitation of columns of droplets at the focal point and at half a wavelength above and below that point. Using this approach, we increased the number of acoustically levitated and merged droplets to 6 compared to 2 in the state-of-the-art. We showed that droplets in a column can be moved and merged with droplets in another column simultaneously and in a controlled manner to perform repeats and/or parallelisation of chemical and biological reactions. To demonstrate our approach experimentally, we built an acoustic levitator with top and bottom surfaces made of 16×16 grid of 40 kHz phased array transducers and integrated optical detection system, studied two acoustic trap generation and movement algorithms, and performed an exemplar enzyme assay. This work has made significant steps towards acoustic levitation and manipulation of large numbers of droplets to eventually significantly reduce the use of the current state-of-the-art tools, microtitre plates and robots, for performing parallelised chemical and biological reactions.
{"title":"Acoustic Levitation and Manipulation of Columns of Droplets with Integrated Optical Detection for Parallelisation of Reactions","authors":"Ruchi Gupta, Nicholas Goddard","doi":"10.1039/d4an01096e","DOIUrl":"https://doi.org/10.1039/d4an01096e","url":null,"abstract":"The most common methodology for performing multiple chemical and biological reactions in parallel is to use microtitre plates with either manual or robotic dispensing of reactants and wash solutions. We envision a paradigm shift where acoustically levitated droplets serve as wells of microtitre plates and are acoustically manipulated to perform chemical and biological reactions in a non-contact fashion. This in turn requires that lines of droplets can be levitated and manipulated simultaneously so that same operations (merge, mix, and detect) can be performed on them in parallel. However, this has not been demonstrated until this work. Because of the nature of acoustic standing waves, a single focus has more than one trap, and can allow levitation of columns of droplets at the focal point and at half a wavelength above and below that point. Using this approach, we increased the number of acoustically levitated and merged droplets to 6 compared to 2 in the state-of-the-art. We showed that droplets in a column can be moved and merged with droplets in another column simultaneously and in a controlled manner to perform repeats and/or parallelisation of chemical and biological reactions. To demonstrate our approach experimentally, we built an acoustic levitator with top and bottom surfaces made of 16×16 grid of 40 kHz phased array transducers and integrated optical detection system, studied two acoustic trap generation and movement algorithms, and performed an exemplar enzyme assay. This work has made significant steps towards acoustic levitation and manipulation of large numbers of droplets to eventually significantly reduce the use of the current state-of-the-art tools, microtitre plates and robots, for performing parallelised chemical and biological reactions.","PeriodicalId":63,"journal":{"name":"Analyst","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142448116","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kwanhwi Ko, Hajun Yoo, Sangheon Han, Won Seok Chang, Donghyun Kim
When exposed to an alternating current (AC) electric field, a polarized microparticle is moved by the interaction between the voltage-induced dipoles and the AC electric field under dielectrophoresis (DEP). The DEP force is widely used for manipulation of microparticles in diverse practical applications such as 3D manipulation, sorting, transfer, and separation of various particles such as living cells. In this study, we propose integration of surface-enhanced Raman spectroscopy (SERS), an extremely sensitive and versatile technique based on Raman scattering of molecules supported by nanostructured materials, with DEP using a microfluidic device. The microfluidic device combines microelectrodes with gold nanohole arrays to characterize electrophysiological and biochemical properties of biological cells. The movement of particles, which varies depending on the electrical properties such as conductivity and permittivity of particles, can be manipulated by the cross-frequency change. For proof of concept, Raman spectroscopy using the DEP-SERS integration was performed for polystyrene beads and biological cells and resulted in an improved signal-to-noise ratio by determining the direction of the DEP force applied to the cells with respect to the applied AC power and collecting them on the nanohole arrays. The result illustrates the potential of the concept for simultaneously examining the electrical and biochemical properties of diverse chemical and biological microparticles in the microfluidic environment.
当暴露在交流（AC）电场中时，极化微粒会在电压引起的偶极子与交流电场的相互作用下发生介电泳（DEP）运动。介电泳力被广泛应用于各种实际应用中的微颗粒操纵，如各种颗粒（如活细胞）的三维操纵、分拣、转移和分离。在本研究中，我们提出利用微流体设备将表面增强拉曼光谱（SERS）与 DEP 相结合，SERS 是一种基于纳米结构材料支持的分子拉曼散射的极其灵敏且用途广泛的技术。该微流体装置将微电极与金纳米孔阵列相结合，用于表征生物细胞的电生理和生化特性。颗粒的运动因颗粒的电特性（如电导率和介电常数）而异，可通过交叉频率变化来操控。为了验证概念，利用 DEP-SERS 集成对聚苯乙烯珠和生物细胞进行了拉曼光谱分析，通过确定施加到细胞上的 DEP 力相对于施加的交流电的方向，并将其收集到纳米孔阵列上，从而提高了信噪比。结果表明，这一概念具有在微流体环境中同时检测各种化学和生物微粒的电学和生物化学特性的潜力。
{"title":"Surface-enhanced Raman spectroscopy with single cell manipulation by microfluidic dielectrophoresis","authors":"Kwanhwi Ko, Hajun Yoo, Sangheon Han, Won Seok Chang, Donghyun Kim","doi":"10.1039/d4an00983e","DOIUrl":"https://doi.org/10.1039/d4an00983e","url":null,"abstract":"When exposed to an alternating current (AC) electric field, a polarized microparticle is moved by the interaction between the voltage-induced dipoles and the AC electric field under dielectrophoresis (DEP). The DEP force is widely used for manipulation of microparticles in diverse practical applications such as 3D manipulation, sorting, transfer, and separation of various particles such as living cells. In this study, we propose integration of surface-enhanced Raman spectroscopy (SERS), an extremely sensitive and versatile technique based on Raman scattering of molecules supported by nanostructured materials, with DEP using a microfluidic device. The microfluidic device combines microelectrodes with gold nanohole arrays to characterize electrophysiological and biochemical properties of biological cells. The movement of particles, which varies depending on the electrical properties such as conductivity and permittivity of particles, can be manipulated by the cross-frequency change. For proof of concept, Raman spectroscopy using the DEP-SERS integration was performed for polystyrene beads and biological cells and resulted in an improved signal-to-noise ratio by determining the direction of the DEP force applied to the cells with respect to the applied AC power and collecting them on the nanohole arrays. The result illustrates the potential of the concept for simultaneously examining the electrical and biochemical properties of diverse chemical and biological microparticles in the microfluidic environment.","PeriodicalId":63,"journal":{"name":"Analyst","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142440528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Amanda French, Kirby P Hobbs, Richard M Cox, Isaac J Arnquist
Interference removal in inductively coupled plasma tandem mass spectrometry (ICP-MS/MS) is strongly dependent on the gas selected for use within the collision/reaction cell. There has been little investigation on the effects that reaction gas impurities may have on the resulting spectra. The reactivity of 60 elements was evaluated using nitric oxide (NO 99.5%) with and without a gas purifier to reduce H2O impurities to < 100 pptV. Experiments were performed using V, Ce, Tl and Th to investigate the effects of purified NO at various flowrates (0.22 – 1.49 mL min-1). Purified NO was shown to significantly mitigate oxy-hydride interferences, improve total ion sensitivity (notable at high gas flows), and shift product distributions advantageously. The reduction in oxy-hydride species results in a product distribution favoring the major expected products, where signals were shown to increase by an order of magnitude. Reduced background and increased signal for the major expected products provides avenues for improving various analytical applications of ICP-MS/MS.
电感耦合等离子体串联质谱法（ICP-MS/MS）的干扰消除在很大程度上取决于碰撞/反应池中选择使用的气体。关于反应气体杂质对所产生光谱的影响的研究还很少。我们使用一氧化氮（NO 99.5%）对 60 种元素的反应性进行了评估，使用或不使用气体净化器将 H2O 杂质降至 100 pptV。使用 V、Ce、Tl 和 Th 进行了实验，以研究纯化的 NO 在不同流速（0.22 - 1.49 mL min-1）下的效果。结果表明，纯化的氮氧化物能明显减轻氧氢干扰，提高总离子灵敏度（在高气体流量下尤为明显），并使产物分布发生有利的变化。氧酸酐种类的减少导致产物分布偏向于主要的预期产物，其信号增加了一个数量级。本底的减少和主要预期产物信号的增加为改进 ICP-MS/MS 的各种分析应用提供了途径。
{"title":"The impact of gas purity on observed reactivity with NO using inductively coupled plasma tandem mass spectrometry","authors":"Amanda French, Kirby P Hobbs, Richard M Cox, Isaac J Arnquist","doi":"10.1039/d4an01227e","DOIUrl":"https://doi.org/10.1039/d4an01227e","url":null,"abstract":"Interference removal in inductively coupled plasma tandem mass spectrometry (ICP-MS/MS) is strongly dependent on the gas selected for use within the collision/reaction cell. There has been little investigation on the effects that reaction gas impurities may have on the resulting spectra. The reactivity of 60 elements was evaluated using nitric oxide (NO 99.5%) with and without a gas purifier to reduce H2O impurities to < 100 pptV. Experiments were performed using V, Ce, Tl and Th to investigate the effects of purified NO at various flowrates (0.22 – 1.49 mL min-1). Purified NO was shown to significantly mitigate oxy-hydride interferences, improve total ion sensitivity (notable at high gas flows), and shift product distributions advantageously. The reduction in oxy-hydride species results in a product distribution favoring the major expected products, where signals were shown to increase by an order of magnitude. Reduced background and increased signal for the major expected products provides avenues for improving various analytical applications of ICP-MS/MS.","PeriodicalId":63,"journal":{"name":"Analyst","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142440579","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the face of worsening water quality and escalating water environmental emergencies, this study developed a paper-based microfluidic disk for rapid, on-site determination of ammonia nitrogen, nitrates, nitrites, and phosphates in water. The method utilizes centrifugal microfluidics and paper-based technology, simplifying the operation while eliminating the need for on-site reagent preparation. Experimental results demonstrate that the disk requires only 80 microliters of water sample and 2 minutes to complete quantitative analysis of the four nutrients, with a coefficient of variation below 1.72% and spike recoveries ranging from 92% to 113%. The development of the disk provides an effective and rapid on-site testing tool for water quality analysis.
{"title":"Designing a Novel Paper-based Microfluidic Disc for rapid and Simultaneous Determination of Multiple Nutrient Salts in Water.","authors":"Zhentao Sun, Youquan Zhao, Yameng Liu, Chen Chen, Hao Chen","doi":"10.1039/d4an01127a","DOIUrl":"https://doi.org/10.1039/d4an01127a","url":null,"abstract":"In the face of worsening water quality and escalating water environmental emergencies, this study developed a paper-based microfluidic disk for rapid, on-site determination of ammonia nitrogen, nitrates, nitrites, and phosphates in water. The method utilizes centrifugal microfluidics and paper-based technology, simplifying the operation while eliminating the need for on-site reagent preparation. Experimental results demonstrate that the disk requires only 80 microliters of water sample and 2 minutes to complete quantitative analysis of the four nutrients, with a coefficient of variation below 1.72% and spike recoveries ranging from 92% to 113%. The development of the disk provides an effective and rapid on-site testing tool for water quality analysis.","PeriodicalId":63,"journal":{"name":"Analyst","volume":null,"pages":null},"PeriodicalIF":4.2,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142439205","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：