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Costa BMDC, Griveau S, d'Orlye F, Bedioui F, da Silva JAF, Varenne A. Microchip electrophoresis and electrochemical detection: A review on a growing synergistic implementation. Electrochim Acta 2021; 391:138928. [DOI: 10.1016/j.electacta.2021.138928] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Huang L, He W, Wang W. A cell electro-rotation micro-device using polarized cells as electrodes. Electrophoresis 2018; 40:784-791. [DOI: 10.1002/elps.201800360] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Revised: 09/28/2018] [Accepted: 10/08/2018] [Indexed: 01/18/2023]
Affiliation(s)
- Liang Huang
- State Key Laboratory of Precision Measurement Technology and Instrument; Department of Precision Instrument; Tsinghua University; Beijing P. R. China
| | - Weihua He
- State Key Laboratory of Precision Measurement Technology and Instrument; Department of Precision Instrument; Tsinghua University; Beijing P. R. China
| | - Wenhui Wang
- State Key Laboratory of Precision Measurement Technology and Instrument; Department of Precision Instrument; Tsinghua University; Beijing P. R. China
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Gomez FJV, Silva MF. Microchip electrophoresis for wine analysis. Anal Bioanal Chem 2016; 408:8643-53. [DOI: 10.1007/s00216-016-9841-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 07/20/2016] [Accepted: 07/27/2016] [Indexed: 10/21/2022]
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Medina-Sánchez M, Ibarlucea B, Pérez N, Karnaushenko DD, Weiz SM, Baraban L, Cuniberti G, Schmidt OG. High-Performance Three-Dimensional Tubular Nanomembrane Sensor for DNA Detection. Nano Lett 2016; 16:4288-96. [PMID: 27266478 DOI: 10.1021/acs.nanolett.6b01337] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
We report an ultrasensitive label-free DNA biosensor with fully on-chip integrated rolled-up nanomembrane electrodes. The hybridization of complementary DNA strands (avian influenza virus subtype H1N1) is selectively detected down to attomolar concentrations, an unprecedented level for miniaturized sensors without amplification. Impedimetric DNA detection with such a rolled-up biosensor shows 4 orders of magnitude sensitivity improvement over its planar counterpart. Furthermore, it is observed that the impedance response of the proposed device is contrary to the expected behavior due to its particular geometry. To further investigate this difference, a thorough model analysis of the measured signal and the electric field calculation is performed, revealing enhanced electron hopping/tunneling along the DNA chains due to an enriched electric field inside the tube. Likewise, conformational changes of DNA might also contribute to this effect. Accordingly, these highly integrated three-dimensional sensors provide a tool to study electrical properties of DNA under versatile experimental conditions and open a new avenue for novel biosensing applications (i.e., for protein, enzyme detection, or monitoring of cell behavior under in vivo like conditions).
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Affiliation(s)
- Mariana Medina-Sánchez
- Institute for Integrative Nanosciences, IFW Dresden , Helmholtzstraße 20, 01069 Dresden, Germany
| | - Bergoi Ibarlucea
- Institute of Materials Science and Max Bergmann Center for Biomaterials, Center for Advancing Electronics Dresden (CfAED), Dresden University of Technology , 01062 Dresden, Germany
| | - Nicolás Pérez
- Institute for Integrative Nanosciences, IFW Dresden , Helmholtzstraße 20, 01069 Dresden, Germany
| | - Dmitriy D Karnaushenko
- Institute for Integrative Nanosciences, IFW Dresden , Helmholtzstraße 20, 01069 Dresden, Germany
| | - Sonja M Weiz
- Institute for Integrative Nanosciences, IFW Dresden , Helmholtzstraße 20, 01069 Dresden, Germany
| | - Larysa Baraban
- Institute of Materials Science and Max Bergmann Center for Biomaterials, Center for Advancing Electronics Dresden (CfAED), Dresden University of Technology , 01062 Dresden, Germany
| | - Gianaurelio Cuniberti
- Institute of Materials Science and Max Bergmann Center for Biomaterials, Center for Advancing Electronics Dresden (CfAED), Dresden University of Technology , 01062 Dresden, Germany
| | - Oliver G Schmidt
- Institute for Integrative Nanosciences, IFW Dresden , Helmholtzstraße 20, 01069 Dresden, Germany
- Material Systems for Nanoelectronics, Chemnitz University of Technology , Reichenhainer Straße 70, 09107 Chemnitz, Germany
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Jivani RR, Lakhtaria GJ, Patadiya DD, Patel LD, Jivani NP, Jhala BP. Biomedical microelectromechanical systems (BioMEMS): Revolution in drug delivery and analytical techniques. Saudi Pharm J 2016; 24:1-20. [PMID: 26903763 PMCID: PMC4719786 DOI: 10.1016/j.jsps.2013.12.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 12/14/2013] [Indexed: 01/19/2023] Open
Abstract
Advancement in microelectromechanical system has facilitated the microfabrication of polymeric substrates and the development of the novel class of controlled drug delivery devices. These vehicles have specifically tailored three dimensional physical and chemical features which together, provide the capacity to target cell, stimulate unidirectional controlled release of therapeutics and augment permeation across the barriers. Apart from drug delivery devices microfabrication technology’s offer exciting prospects to generate biomimetic gastrointestinal tract models. BioMEMS are capable of analysing biochemical liquid sample like solution of metabolites, macromolecules, proteins, nucleic acid, cells and viruses. This review summarized multidisciplinary application of biomedical microelectromechanical systems in drug delivery and its potential in analytical procedures.
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Affiliation(s)
- Rishad R Jivani
- Department of Pharmaceutics, C. U. Shah College of Pharmacy & Research, Surendranagar, Wadhwan, Gujarat, India
| | - Gaurang J Lakhtaria
- Department of Pharmaceutics, C. U. Shah College of Pharmacy & Research, Surendranagar, Wadhwan, Gujarat, India
| | - Dhaval D Patadiya
- Department of Pharmaceutics, C. U. Shah College of Pharmacy & Research, Surendranagar, Wadhwan, Gujarat, India
| | - Laxman D Patel
- Department of Pharmaceutics, C. U. Shah College of Pharmacy & Research, Surendranagar, Wadhwan, Gujarat, India
| | - Nurrudin P Jivani
- Department of Pharmaceutics, C. U. Shah College of Pharmacy & Research, Surendranagar, Wadhwan, Gujarat, India
| | - Bhagyesh P Jhala
- Department of Pharmaceutics, C. U. Shah College of Pharmacy & Research, Surendranagar, Wadhwan, Gujarat, India
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Duarte Junior GF, Fracassi da Silva JA, Mendonça Francisco KJ, do Lago CL, Carrilho E, Coltro WKT. Metalless electrodes for capacitively coupled contactless conductivity detection on electrophoresis microchips. Electrophoresis 2015; 36:1935-40. [DOI: 10.1002/elps.201500033] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Revised: 03/05/2015] [Accepted: 03/13/2015] [Indexed: 01/17/2023]
Affiliation(s)
| | - José Alberto Fracassi da Silva
- Instituto de Química; Universidade Estadual de Campinas; Campinas São Paulo Brasil
- Instituto Nacional de Ciência e Tecnologia de Bioanalítica; Campinas São Paulo Brasil
| | | | | | - Emanuel Carrilho
- Instituto de Química de São Carlos; Universidade de São Paulo; São Carlos São Paulo Brasil
- Instituto Nacional de Ciência e Tecnologia de Bioanalítica; Campinas São Paulo Brasil
| | - Wendell K. T. Coltro
- Instituto de Química; Universidade Federal de Goiás; Goiânia Goiás Brasil
- Instituto Nacional de Ciência e Tecnologia de Bioanalítica; Campinas São Paulo Brasil
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Martinez-Cisneros CS, Sanchez S, Xi W, Schmidt OG. Ultracompact three-dimensional tubular conductivity microsensors for ionic and biosensing applications. Nano Lett 2014; 14:2219-24. [PMID: 24655094 PMCID: PMC3985718 DOI: 10.1021/nl500795k] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
We present ultracompact three-dimensional tubular structures integrating Au-based electrodes as impedimetric microsensors for the in-flow determination of mono- and divalent ionic species and HeLa cells. The microsensors show an improved performance of 2 orders of magnitude (limit of detection = 0.1 nM for KCl) compared to conventional planar conductivity detection systems integrated in microfluidic platforms and the capability to detect single HeLa cells in flowing phosphate buffered saline. These highly integrated conductivity tubular sensors thus open new possibilities for lab-in-a-tube devices for bioapplications such as biosensing and bioelectronics.
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Lima RS, Piazzetta MHO, Gobbi AL, Segato TP, Cabral MF, Machado SAS, Carrilho E. Highly sensitive contactless conductivity microchips based on concentric electrodes for flow analysis. Chem Commun (Camb) 2013; 49:11382-4. [DOI: 10.1039/c3cc45797d] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Shen D, Li Y, Zhang Z, Zhang P, Kang Q. Determination of amino acids by capillary electrophoresis with differential resonant contactless conductivity detector. Talanta 2013; 104:39-43. [DOI: 10.1016/j.talanta.2012.11.027] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Revised: 11/08/2012] [Accepted: 11/10/2012] [Indexed: 11/15/2022]
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Thredgold LD, Khodakov DA, Ellis AV, Lenehan CE. On-chip capacitively coupled contactless conductivity detection using “injected” metal electrodes. Analyst 2013; 138:4275-9. [DOI: 10.1039/c3an00870c] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Gomez FJV, Monasterio RP, Vargas VCS, Silva MF. Analytical characterization of wine and its precursors by capillary electrophoresis. Electrophoresis 2012; 33:2240-52. [PMID: 22887148 DOI: 10.1002/elps.201100595] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The accurate determination of marker chemical species in grape, musts, and wines presents a unique analytical challenge with high impact on diverse areas of knowledge such as health, plant physiology, and economy. Capillary electromigration techniques have emerged as a powerful tool, allowing the separation and identification of highly polar compounds that cannot be easily separated by traditional HPLC methods, providing complementary information and permitting the simultaneous analysis of analytes with different nature in a single run. The main advantage of CE over traditional methods for wine analysis is that in most cases samples require no treatment other than filtration. The purpose of this article is to present a revision on capillary electromigration methods applied to the analysis of wine and its precursors over the last decade. The current state of the art of the topic is evaluated, with special emphasis on the natural compounds that have allowed wine to be considered as a functional food. The most representative revised compounds are phenolic compounds, amino acids, proteins, elemental species, mycotoxins, and organic acids. Finally, a discussion on future trends of the role of capillary electrophoresis in the field of analytical characterization of wines for routine analysis, wine classification, as well as multidisciplinary aspects of the so-called "from soil to glass" chain is presented.
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Affiliation(s)
- Federico J V Gomez
- Instituto de Biología Agrícola de Mendoza (IBAM-CONICET), Facultad de Ciencias Agrarias, Universidad Nacional de Cuyo, Mendoza, Argentina
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Lima RS, Piazzetta MHO, Gobbi AL, Rodrigues-Filho UP, Nascente PAP, Coltro WKT, Carrilho E. Contactless conductivity biosensor in microchip containing folic acid as bioreceptor. Lab Chip 2012; 12:1963-1966. [PMID: 22549415 DOI: 10.1039/c2lc40157f] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We report a glass/PDMS-based microfluidic biosensor that integrates contactless conductivity transduction and folic acid, a target for tumor biomarker, as a bioreceptor. The device presents relevant advantages such as direct determination--dismiss the use of redox mediators as in faradaic electrochemical techniques--and the absence of the known drawbacks related to the electrode-solution interface. Characterizations of the functionalization processes and chemical sensor are described in this communication.
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Affiliation(s)
- Renato S Lima
- Instituto de Química de São Carlos, Universidade de São Paulo, São Carlos, SP, Brazil
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Lima RS, Segato TP, Gobbi AL, Coltro WKT, Carrilho E. Doping of a dielectric layer as a new alternative for increasing sensitivity of the contactless conductivity detection in microchips. Lab Chip 2011; 11:4148-4151. [PMID: 22045405 DOI: 10.1039/c1lc20757a] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
This communication describes a new procedure to increase the sensitivity of C(4)D in PDMS/glass microchips. The method consists in doping the insulating layer (PDMS) over the electrodes with nanoparticles of TiO(2), increasing thus its dielectric constant. The experimental protocol is simple, inexpensive, and fast.
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Affiliation(s)
- Renato Sousa Lima
- Instituto de Química de São Carlos, Universidade de São Paulo, São Carlos, Brazil
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Tomazelli Coltro WK, Fracassi da Silva JA, Carrilho E. Rapid prototyping of polymeric electrophoresis microchips with integrated electrodes for contactless conductivity detection. Anal Methods 2011; 3:168-172. [PMID: 32938126 DOI: 10.1039/c0ay00486c] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
A simple and easy approach to produce polymeric microchips with integrated copper electrodes for capacitively coupled contactless conductivity detection (C4D) is described. Copper electrodes were fabricated using a printed circuit board (PCB) as an inexpensive thin-layer of metal. The electrode layout was first drawn and laser printed on a wax paper sheet. The toner layer deposited on the paper sheet was thermally transferred to the PCB surface working as a mask for wet chemical etching of the copper layer. After the etching step, the toner was removed with an acetonitrile-dampened cotton. A poly(ethylene terephthalate) (PET) film coated with a thin thermo-sensitive adhesive layer was used to laminate the PCB plate providing an insulator layer of the electrodes to perform C4D measurements. Electrophoresis microchannels were fabricated in poly(dimethylsiloxane) (PDMS) by soft lithography and reversibly sealed against the PET film. These hybrid PDMS/PET chips exhibited a stable electroosmotic mobility of 4.25 ± 0.04 × 10-4 V cm-2 s-1, at pH 6.1, over fifty runs. Efficiencies ranging from 1127 to 1690 theoretical plates were obtained for inorganic cations.
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Affiliation(s)
- Wendell Karlos Tomazelli Coltro
- Instituto de Química, Universidade Federal de Goiás, Campus Samambaia, 74001-970, Goiânia, GO, Brazil.
- Instituto Nacional de Ciência e Tecnologia de Bioanalítica, Campinas, SP, Brazil
| | - Josà Alberto Fracassi da Silva
- Instituto Nacional de Ciência e Tecnologia de Bioanalítica, Campinas, SP, Brazil
- Instituto de Química, Universidade Estadual de Campinas, 13083-970, Campinas, SP, Brazil.
| | - Emanuel Carrilho
- Instituto Nacional de Ciência e Tecnologia de Bioanalítica, Campinas, SP, Brazil
- Instituto de Química de São Carlos, Universidade de São Paulo, 13566-970, São Carlos, SP, Brazil.
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Yang M, Yu Y, Shen F, Dierks K, Fang W, Li Q. Detection of Copper Ion with Laser-Induced Fluorescence in a Capillary Electrophoresis Microchip. ANAL LETT 2010. [DOI: 10.1080/00032711003763657] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Fercher G, Haller A, Smetana W, Vellekoop MJ. End-to-End Differential Contactless Conductivity Sensor for Microchip Capillary Electrophoresis. Anal Chem 2010; 82:3270-5. [DOI: 10.1021/ac100041p] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Georg Fercher
- Institute of Sensor and Actuator Systems, Vienna University of Technology, Vienna, Austria, and IMA GmbH, Wiener Neustadt, Austria
| | - Anna Haller
- Institute of Sensor and Actuator Systems, Vienna University of Technology, Vienna, Austria, and IMA GmbH, Wiener Neustadt, Austria
| | - Walter Smetana
- Institute of Sensor and Actuator Systems, Vienna University of Technology, Vienna, Austria, and IMA GmbH, Wiener Neustadt, Austria
| | - Michael J. Vellekoop
- Institute of Sensor and Actuator Systems, Vienna University of Technology, Vienna, Austria, and IMA GmbH, Wiener Neustadt, Austria
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Hou HH, Tsai CH, Fu LM, Yang RJ. Experimental and numerical investigation into micro-flow cytometer with 3-D hydrodynamic focusing effect and micro-weir structure. Electrophoresis 2009; 30:2507-15. [DOI: 10.1002/elps.200900012] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Fercher G, Smetana W, Vellekoop MJ. Microchip electrophoresis in low-temperature co-fired ceramics technology with contactless conductivity measurement. Electrophoresis 2009; 30:2516-22. [DOI: 10.1002/elps.200800654] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Johns C, Breadmore MC, Macka M, Ryvolová M, Haddad PR. Recent significant developments in detection and method development for the determination of inorganic ions by CE. Electrophoresis 2009; 30 Suppl 1:S53-67. [DOI: 10.1002/elps.200900103] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Abstract
This paper presents a parametric experimental investigation into the electrokinetic instability (EKI) phenomenon within three different types of microfluidic device, namely T-type, cross-shaped, and cross-form with an expansion configuration. The critical electric field strength at which the EKI phenomenon is induced is examined as a function of the conductivity ratio, the microchannel width, the expansion ratio, and the surface treatment of the microchannel walls. It is found that the critical electric field strength associated with the onset of EKI is strongly dependent on the conductivity ratio of the two samples within the microfluidic device and reduces as the channel width increases. The surfaces of the microchannel walls are coated with hydrophilic or hydrophobic organic-based spin-on-glass (SOG) nanofilms for glass-based microchips. The experimental results indicate that no significant difference exists in the critical electric field strengths in the hydrophilic or hydrophobic SOG-coated microchannels, respectively. However, for a given conductivity ratio and microchannel width, the critical strength of the electric field is slightly lower in the SOG-coated microchannels than in the non-coated channels. In general, the results presented in this study demonstrate the potential for designing and controlling on-chip assays requiring the manipulation of samples with high conductivity gradients, and provide a useful general reference for avoiding EKI effects in capillary electrophoresis analysis applications.
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Affiliation(s)
- Lung-Ming Fu
- Department of Materials Engineering, National Pingtung University of Science and Technology, Pingtung, Taiwan
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Prest JE, Baldock SJ, Fielden PR, Goddard NJ, Treves Brown BJ. A miniaturised isotachophoresis method for magnesium determination. Anal Bioanal Chem 2009; 394:1299-305. [DOI: 10.1007/s00216-009-2603-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2008] [Revised: 12/22/2008] [Accepted: 01/07/2009] [Indexed: 10/21/2022]
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Kubán P, Hauser PC. Evaluation of microchip capillary electrophoresis with external contactless conductivity detection for the determination of major inorganic ions and lithium in serum and urine samples. Lab Chip 2008; 8:1829-1836. [PMID: 18941681 DOI: 10.1039/b802973c] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The determination of inorganic ions in clinical samples in less than 90 seconds was demonstrated for microchip capillary electrophoresis using capacitively coupled contactless conductivity detection (C(4)D). Bare electrophoresis chips were used in combination with external electrodes which were part of the chip holder. In order to achieve the required selectivity and sensitivity, an optimization of the electrode layout was carried out. Limits of detection (LOD) of 1 microM for K(+), 1.5 microM for Ca(2+), 3 microM for Na(+), 1.75 microM for Mg(2+) and 7.5 microM for Li(+) were achieved. The determination of inorganic cations (NH(4)(+), K(+), Na(+), Ca(2+), Mg(2+)) and anions (Cl(-), NO(3)(-), SO(4)(2-), phosphate) in blood serum and urine samples was possible in one common electrolyte solution containing 15 mM L-arginine, 10.75 mM maleic acid and 1.5 mM 18-crown-6 at pH 5.90 by simply switching the separation voltage from positive to negative polarity. Lithium, present at significant levels when used for therapeutic purposes, can also be determined in blood serum using a slightly modified background electrolyte solution.
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Affiliation(s)
- Pavel Kubán
- Department of Chemistry, University of Basel, Spitalstrasse 51, 4056, Basel, Switzerland
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Chang CL, Hou HH, Fu LM, Tsai CH. A low-leakage sample plug injection scheme for crossform microfluidic capillary electrophoresis devices incorporating a restricted cross-channel intersection. Electrophoresis 2008; 29:3135-44. [PMID: 18600833 DOI: 10.1002/elps.200800022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
This study develops a crossform CE microfluidic device in which a single-circular barrier or a double-circular barrier is introduced at the cross-channel intersection. Utilizing a conventional crossform injection scheme, it is shown that these barriers reduce sample leakage and deliver a compact sample band into the separation channel, thereby ensuring an enhanced detection performance. A series of numerical and experimental investigations are performed to investigate the effects of the barrier type and the barrier ratio on the flow streamlines within the microchannel and to clarify their respective effects on the sample leakage ratio and sample plug variance during the injection process. The results indicate that a single-circular barrier injector with a barrier ratio greater than 20% and a double-circular barrier injector with a barrier ratio greater than 40% minimize the sample leakage ratio and produce a compact sample plug. As a result, both injectors have an excellent potential for use in high-quality, high-throughput chemical analysis procedures and in many other applications throughout the micro-total analysis systems field.
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Affiliation(s)
- Chin-Lung Chang
- Department of Vehicle Engineering, National Pingtung University of Science and Technology, Pingtung, Taiwan
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Kubáň P, Hauser PC. A review of the recent achievements in capacitively coupled contactless conductivity detection. Anal Chim Acta 2008; 607:15-29. [DOI: 10.1016/j.aca.2007.11.045] [Citation(s) in RCA: 215] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2007] [Revised: 11/22/2007] [Accepted: 11/27/2007] [Indexed: 11/21/2022]
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Abstract
This study presents a new approach for high-performance detection sensors for MEMS-based capillary electrophoresis chips to substitute laser induced fluorescence (LIF) detection systems. The developed sensors easily integrate with well-known microfabrication techniques for glass-based microfluidic devices. Three-dimensional gold electrodes are structured in enveloping side channels by sputtering and patterned using a standard "lift-off" process. The variations in the capacitance between the electrodes in the side channels are measured as different samples and ions pass through the detection region of the capillary electrophoresis separation channel. Samples of beer, white wine and milk are each mixed in different buffer solutions, then successfully separated and detected using the developed device. The proposed high-performance detection sensors have microscale dimensions and provide a critical step towards the realization of the lab-on-a-chip concept.
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Affiliation(s)
- Lung-Ming Fu
- Department of Materials Engineering, National Pingtung University of Science and Technology, 912 Pingtung, Taiwan
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Abstract
This paper presents a novel microfluidic capillary electrophoresis (CE) device featuring a double-T-form injection system and an expansion chamber located at the inlet of the separation channel. This study addresses the principal material transport mechanisms depending on parameters such as the expansion ratio, the expansion length, the fluid flow. Its design utilizes a double-L injection technique and combines the expansion chamber to minimize the sample leakage effect and to deliver a high-quality sample plug into the separation channel so that the detection performance of the device is enhanced. Experimental and numerical testing of the proposed microfluidic device that integrates an expansion chamber located at the inlet of the separation channel confirms its ability to increase the separation efficiency by improving the sample plug shape and orientation. The novel microfluidic capillary electrophoresis device presented in this paper has demonstrated a sound potential for future use in high-quality, high-throughput chemical analysis applications and throughout the micro-total-analysis systems field.
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Affiliation(s)
- Lung-Ming Fu
- Department of Materials Engineering, National Pingtung University of Science and Technology, Pingtung, Taiwan 912
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