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De Peña AC, Zimmer D, Gutterman-Johns E, Chen NM, Tripathi A, Bailey-Hytholt CM. Electrophoretic Microfluidic Characterization of mRNA- and pDNA-Loaded Lipid Nanoparticles. ACS APPLIED MATERIALS & INTERFACES 2024; 16:26984-26997. [PMID: 38753459 DOI: 10.1021/acsami.4c00208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2024]
Abstract
Lipid nanoparticles (LNPs) are clinically advanced nonviral gene delivery vehicles with a demonstrated ability to address viral, oncological, and genetic diseases. However, the further development of LNP therapies requires rapid analytical techniques to support their development and manufacturing. The method developed and described in this paper presents an approach to rapidly and accurately analyze LNPs for optimized therapeutic loading by utilizing an electrophoresis microfluidic platform to analyze the composition of LNPs with different clinical lipid compositions (Onpattro, Comirnaty, and Spikevax) and nucleic acid (plasmid DNA (pDNA) and messenger RNA (mRNA)) formulations. This method enables the high-throughput screening of LNPs using a 96- or 384-well plate with approximate times of 2-4 min per sample using a total volume of 11 μL. The lipid analysis requires concentrations approximately between 109 and 1010 particles/mL and has an average precision error of 10.4% and a prediction error of 19.1% when compared to using a NanoSight, while the nucleic acid analysis requires low concentrations of 1.17 ng/μL for pDNA and 0.17 ng/μL for mRNA and has an average precision error of 4.8% and a prediction error of 9.4% when compared to using a PicoGreen and RiboGreen assay. In addition, our method quantifies the relative concentration of nucleic acid per LNP. Utilizing this approach, we observed an average of 263 ± 62.2 mRNA per LNP and 126.3 ± 21.2 pDNA per LNP for the LNP formulations used in this study, where the accuracy of these estimations is dependent on reference standards. We foresee the utility of this technique in the high-throughput characterization of LNPs during manufacturing and formulation research and development.
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Affiliation(s)
- Adriana Coll De Peña
- Center for Biomedical Engineering, School of Engineering, Brown University, Providence, Rhode Island 02912, United States
| | - Daniel Zimmer
- Department of Chemical Engineering, Worcester Polytechnic Institute, Worcester, Massachusetts 01609, United States
| | - Everett Gutterman-Johns
- Department of Molecular Biology, Cell Biology, and Biochemistry, Division of Biology and Medicine, Brown University, Providence, Rhode Island 02912, United States
| | - Nicole M Chen
- Department of Molecular Biology, Cell Biology, and Biochemistry, Division of Biology and Medicine, Brown University, Providence, Rhode Island 02912, United States
| | - Anubhav Tripathi
- Center for Biomedical Engineering, School of Engineering, Brown University, Providence, Rhode Island 02912, United States
| | - Christina M Bailey-Hytholt
- Department of Chemical Engineering, Worcester Polytechnic Institute, Worcester, Massachusetts 01609, United States
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2
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Kitagawa F, Yonekura T, Nukatsuka I. On-line sample preconcentration by LVSEP-FASI with simple voltage control on Y-channel chips. ANAL SCI 2024; 40:235-241. [PMID: 37971694 DOI: 10.1007/s44211-023-00456-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 10/17/2023] [Indexed: 11/19/2023]
Abstract
To eliminate complicated voltage controls for highly sensitive microchip electrophoresis (MCE) analyses on the basis of combining two online sample preconcentration techniques, large-volume sample stacking with an electroosmotic flow (EOF) pump (LVSEP) and field-amplified sample injection (FASI), cross-channel microchips and a multichannel high-voltage power supply were replaced to Y-channel chips and a conventional power supply designed for capillary electrophoresis, respectively. By simple switching of the electric circuit after the LVSEP-FASI sample enrichments, the focused analytes could be separated during anodic migration in a separation channel. In the LVSEP-FASI analysis of fluorescein using the Y-channel microchip, the maximum sensitivity enhancement factor (SEF) of 7400 was achieved, resulting in a 30-fold detectability increase compared to the conventional LVSEP. The developed method was applied to the oligosaccharide analysis in MCE. As a result, the SEF for maltotriose was improved from 450 to 2300 and the baseline separation of the oligosaccharides was achieved without any complicated voltage control in LVSEP-FASI on the Y-channel chips.
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Affiliation(s)
- Fumihiko Kitagawa
- Department of Frontier Materials Chemistry, Graduate School of Science and Technology, Hirosaki University, 3 Bunkyo-cho, Hirosaki, Aomori, 036-8561, Japan.
| | - Takahiro Yonekura
- Department of Frontier Materials Chemistry, Graduate School of Science and Technology, Hirosaki University, 3 Bunkyo-cho, Hirosaki, Aomori, 036-8561, Japan
| | - Isoshi Nukatsuka
- Department of Frontier Materials Chemistry, Graduate School of Science and Technology, Hirosaki University, 3 Bunkyo-cho, Hirosaki, Aomori, 036-8561, Japan
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3
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Naghdi E, Moran GE, Reinau ME, De Malsche W, Neusüß C. Concepts and recent advances in microchip electrophoresis coupled to mass spectrometry: Technologies and applications. Electrophoresis 2023; 44:246-267. [PMID: 35977423 DOI: 10.1002/elps.202200179] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 08/11/2022] [Accepted: 08/13/2022] [Indexed: 02/01/2023]
Abstract
The online coupling of microchip electrophoresis (ME) as a fast, highly efficient, and low-cost miniaturized separation technique to mass spectrometry (MS) as an information-rich and sensitive characterization technique results in ME-MS an attractive tool for various applications. In this paper, we review the basic concepts and latest advances in technology for ME coupled to MS during the period of 2016-2021, covering microchip materials, structures, fabrication techniques, and interfacing to electrospray ionization (ESI)-MS and matrix-assisted laser desorption/ionization-MS. Two critical issues in coupling ME and ESI-MS include the electrical connection used to define the electrophoretic field strength along the separation channel and the generation of the electrospray for MS detection, as well as, a miniaturized ESI-tip. The recent commercialization of ME-MS in zone electrophoresis and isoelectric focusing modes has led to the widespread application of these techniques in academia and industry. Here we summarize recent applications of ME-MS for the separation and detection of antibodies, proteins, peptides, carbohydrates, metabolites, and so on. Throughout the paper these applications are discussed in the context of benefits and limitations of ME-MS in comparison to alternative techniques.
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Affiliation(s)
- Elahe Naghdi
- Department of Chemistry, Aalen University, Aalen, Germany
| | - Griffin E Moran
- Novo Nordisk A/S, Global Research Technologies, Maaloev, Denmark
| | | | - Wim De Malsche
- µFlow group, Department of Chemical Engineering, Vrije Universiteit Brussel, Brussels, Belgium
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4
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Dispas A, Emonts P, Fillet M. Microchip electrophoresis: A suitable analytical technique for pharmaceuticals quality control? A critical review. Trends Analyt Chem 2021. [DOI: 10.1016/j.trac.2021.116266] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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5
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Lavrentovich OD. Design of nematic liquid crystals to control microscale dynamics. LIQUID CRYSTALS REVIEWS 2021; 8:59-129. [PMID: 34956738 PMCID: PMC8698256 DOI: 10.1080/21680396.2021.1919576] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 04/11/2021] [Indexed: 05/25/2023]
Abstract
The dynamics of small particles, both living such as swimming bacteria and inanimate, such as colloidal spheres, has fascinated scientists for centuries. If one could learn how to control and streamline their chaotic motion, that would open technological opportunities in the transformation of stored or environmental energy into systematic motion, with applications in micro-robotics, transport of matter, guided morphogenesis. This review presents an approach to command microscale dynamics by replacing an isotropic medium with a liquid crystal. Orientational order and associated properties, such as elasticity, surface anchoring, and bulk anisotropy, enable new dynamic effects, ranging from the appearance and propagation of particle-like solitary waves to self-locomotion of an active droplet. By using photoalignment, the liquid crystal can be patterned into predesigned structures. In the presence of the electric field, these patterns enable the transport of solid and fluid particles through nonlinear electrokinetics rooted in anisotropy of conductivity and permittivity. Director patterns command the dynamics of swimming bacteria, guiding their trajectories, polarity of swimming, and distribution in space. This guidance is of a higher level of complexity than a simple following of the director by rod-like microorganisms. Namely, the director gradients mediate hydrodynamic interactions of bacteria to produce an active force and collective polar modes of swimming. The patterned director could also be engraved in a liquid crystal elastomer. When an elastomer coating is activated by heat or light, these patterns produce a deterministic surface topography. The director gradients define an activation force that shapes the elastomer in a manner similar to the active stresses triggering flows in active nematics. The patterned elastomer substrates could be used to define the orientation of cells in living tissues. The liquid-crystal guidance holds a major promise in achieving the goal of commanding microscale active flows.
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Affiliation(s)
- Oleg D Lavrentovich
- Advanced Materials and Liquid Crystal Institute, Department of Physics, Materials Science Graduate Program, Kent State University, Kent, OH 44242, USA
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6
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Liu Y, Xia L, Dutta D. Reduction in sample injection bias using pressure gradients generated on chip. Electrophoresis 2021; 42:983-990. [PMID: 33569844 DOI: 10.1002/elps.202000299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 01/21/2021] [Accepted: 01/29/2021] [Indexed: 11/10/2022]
Abstract
Sample injection in microchip-based capillary zone electrophoresis (CZE) frequently rely on the use of electric fields which can introduce differences in the injected volume for the various analytes depending on their electrophoretic mobilities and molecular diffusivities. While such injection biases may be minimized by employing hydrodynamic flows during the injection process, this approach typically requires excellent dynamic control over the pressure gradients applied within a microfluidic network. The current article describes a microchip device that offers this needed control by generating pressure gradients on-chip via electrokinetic means to minimize the dead volume in the system. In order to realize the desired pressure-generation capability, an electric field was applied across two channel segments of different depths to produce a mismatch in the electroosmotic flow rate at their junction. The resulting pressure-driven flow was then utilized to introduce sample zones into a CZE channel with minimal injection bias. The reported injection strategy allowed the introduction of narrow sample plugs with spatial standard deviations down to about 45 μm. This injection technique was later integrated to a capillary zone electrophoresis process for analyzing amino acid samples yielding separation resolutions of about 4-6 for the analyte peaks in a 3 cm long analysis channel.
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Affiliation(s)
- Yukari Liu
- Department of Chemistry, University of Wyoming, Laramie, WY, 82071, USA
| | - Ling Xia
- Department of Chemistry, University of Wyoming, Laramie, WY, 82071, USA
| | - Debashis Dutta
- Department of Chemistry, University of Wyoming, Laramie, WY, 82071, USA
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7
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Nouwairi RL, O'Connell KC, Gunnoe LM, Landers JP. Microchip Electrophoresis for Fluorescence-Based Measurement of Polynucleic Acids: Recent Developments. Anal Chem 2020; 93:367-387. [PMID: 33351599 DOI: 10.1021/acs.analchem.0c04596] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Renna L Nouwairi
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22903, United States
| | - Killian C O'Connell
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22903, United States
| | - Leah M Gunnoe
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22903, United States
| | - James P Landers
- Department of Chemistry, University of Virginia, Charlottesville, Virginia 22903, United States.,Department of Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, Virginia 22903, United States.,Department of Pathology, University of Virginia Health Science Center, Charlottesville, Virginia 22903, United States
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8
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Duarte LM, Moreira RC, Coltro WKT. Nonaqueous electrophoresis on microchips: A review. Electrophoresis 2020; 41:434-448. [DOI: 10.1002/elps.201900238] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 10/14/2019] [Accepted: 11/20/2019] [Indexed: 01/16/2023]
Affiliation(s)
- Lucas M. Duarte
- Instituto de QuímicaUniversidade Federal de Goiás Goiânia GO Brazil
| | - Roger C. Moreira
- Instituto de QuímicaUniversidade Federal de Goiás Goiânia GO Brazil
| | - Wendell K. T. Coltro
- Instituto de QuímicaUniversidade Federal de Goiás Goiânia GO Brazil
- Instituto Nacional de Ciência e Tecnologia de Bioanalítica Campinas SP Brazil
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9
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Basati Y, Mohammadipour OR, Niazmand H. Numerical and analytical analysis of a robust flow regulator in electroosmotic microfluidic networks. Chem Eng Sci 2019. [DOI: 10.1016/j.ces.2019.115232] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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10
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Karlinsey JM. Sample Injection Techniques. Methods Mol Biol 2019; 1906:55-64. [PMID: 30488384 DOI: 10.1007/978-1-4939-8964-5_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Sample introduction is an important consideration in any microchip electrophoresis (ME) separation. The number of applications and level of complexity of ME devices continue to increase, but the introduction of sample into the separation channel has remained relatively constant. This work describes the most common electrophoretic methods of performing sample injection for ME applications using electroosmotic flow (EOF), providing both a transition from capillary electrophoresis (CE) separations and a straightforward entry point into ME.
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11
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Vorauer-Uhl K, Lhota G. Quantification of Recombinant Products in Yeast. Methods Mol Biol 2019; 1923:385-428. [PMID: 30737753 DOI: 10.1007/978-1-4939-9024-5_20] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Quantification of various proteins expressed in yeast can be performed by different methods. In this respect, classical as well as advanced techniques can be applied, where the analysis of crude supernatants is of special interest in screening but also manufacturing.The following chapter addresses the analytical background of the introduced methods followed by specific recommendations for the quantification of different products of industrial interest. The method portfolio includes electrophoresis, chromatography, and ELISA as classical techniques, but also biosensor-based, microfluidic and automated, miniaturized methods are introduced. Furthermore, individual strengths and perceived limitations are summarized.Although prominent examples are described, it should be noted that individual modifications are required according to host and cultivation mode.
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Affiliation(s)
- Karola Vorauer-Uhl
- Department of Biotechnology, University of Natural Resources and Life Sciences Vienna (BOKU), Vienna, Austria.
| | - Gabriele Lhota
- Department of Biotechnology, University of Natural Resources and Life Sciences Vienna (BOKU), Vienna, Austria
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12
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Gunawardhana SM, Lunte SM. Continuous monitoring of adenosine and its metabolites using microdialysis coupled to microchip electrophoresis with amperometric detection. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2018; 10:3737-3744. [PMID: 31579297 PMCID: PMC6774626 DOI: 10.1039/c8ay01041b] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Rapid monitoring of concentration changes of neurotransmitters and energy metabolites is important for understanding the biochemistry of neurological disease as well as for developing therapeutic options. This paper describes the development of a separation-based sensor using microchip electrophoresis (ME) with electrochemical (EC) detection coupled to microdialysis (MD) sampling for continuous on-line monitoring of adenosine and its downstream metabolites. The device was fabricated completely in PDMS. End-channel electrochemical detection was accomplished using a carbon fiber working electrode embedded in the PDMS. The separation conditions for adenosine, inosine, hypoxanthine, and guanosine were investigated using a ME-EC chip with a 5-cm long separation channel. The best resolution was achieved using a background electrolyte consisting of 35 mM sodium borate at pH 10, 15% dimethyl sulfoxide (DMSO), and 2 mM sodium dodecyl sulphate (SDS), and a field strength of 222 V/cm. Under these conditions, all four purines were separated in less than 85 s. Using a working electrode detection potential of 1.4 vs Ag/AgCl, the limits of detection were 25, 33, 10, and 25 μM for adenosine, inosine, hypoxanthine, and guanosine, respectively. The ME-EC chip was then coupled to microdialysis sampling using a novel all-PDMS microdialysis-microchip interface that was reversibly sealed. This made alignment of the working electrode with the end of the separation channel much easier and more reproducible than could be obtained with previous MD-ME-EC systems. The integrated device was then used to monitor the enzymatic conversion of adenosine to inosine in vitro.
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Affiliation(s)
- Shamal M Gunawardhana
- Ralph N. Adams Institute for Bioanalytical Chemistry, University of Kansas, Lawrence, KS, USA
- Department of Chemistry, University of Kansas, Lawrence, KS, USA
| | - Susan M Lunte
- Ralph N. Adams Institute for Bioanalytical Chemistry, University of Kansas, Lawrence, KS, USA
- Department of Chemistry, University of Kansas, Lawrence, KS, USA
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS, USA
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13
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YANG MP, HUANG Z, XIE Y, YOU H. Development of Microchip Electrophoresis and Its Applications in Ion Detection. CHINESE JOURNAL OF ANALYTICAL CHEMISTRY 2018. [DOI: 10.1016/s1872-2040(18)61085-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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14
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Wu W. A pressure-driven gas-diffusion/permeation micropump for self-activated sample transport in an extreme micro-environment. Analyst 2018; 143:4819-4835. [DOI: 10.1039/c8an01120f] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The pressure-driven gas-diffusion/permeation micropump is highlighted for stable microdroplet/liquid delivery under extreme conditions,e.g.high temperature, and a three-dimensional, long-distance and complex-topology microchannel.
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Affiliation(s)
- Wenming Wu
- State Key Laboratory of Applied Optics
- Changchun Institute of Optics
- Fine Mechanics and Physics
- Chinese Academy of Sciences
- Changchun
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15
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Zeid AM, Kaji N, Nasr JJM, Belal F, Walash MI, Baba Y. Determination of baclofen and vigabatrin by microchip electrophoresis with fluorescence detection: application of field-enhanced sample stacking and dynamic pH junction. NEW J CHEM 2018. [DOI: 10.1039/c8nj00829a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A novel microchip gel electrophoretic method for the assay of baclofen and vigabatrin for the first time.
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Affiliation(s)
- Abdallah M. Zeid
- Department of Biomolecular Engineering
- Graduate School of Engineering
- Nagoya University
- Nagoya 464-8603
- Japan
| | - Noritada Kaji
- Department of Biomolecular Engineering
- Graduate School of Engineering
- Nagoya University
- Nagoya 464-8603
- Japan
| | - Jenny Jeehan M. Nasr
- Department of Pharmaceutical Analytical Chemistry
- Faculty of Pharmacy
- Mansoura University
- Mansoura
- Egypt
| | - Fathalla Belal
- Department of Pharmaceutical Analytical Chemistry
- Faculty of Pharmacy
- Mansoura University
- Mansoura
- Egypt
| | - Mohamed I. Walash
- Department of Pharmaceutical Analytical Chemistry
- Faculty of Pharmacy
- Mansoura University
- Mansoura
- Egypt
| | - Yoshinobu Baba
- Department of Biomolecular Engineering
- Graduate School of Engineering
- Nagoya University
- Nagoya 464-8603
- Japan
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16
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Novel volumetric method for highly repeatable injection in microchip electrophoresis. Anal Chim Acta 2017; 985:129-140. [PMID: 28864183 DOI: 10.1016/j.aca.2017.05.037] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 05/22/2017] [Accepted: 05/22/2017] [Indexed: 12/25/2022]
Abstract
A novel injector for microchip electrophoresis (MCE) has been designed and evaluated that achieves very high repeatability of injection volume suitable for quantitative analysis. It eliminates the injection biases in electrokinetic injection and the dependence on pressure and sample properties in hydrodynamic injection. The microfluidic injector, made of poly(dimethylsiloxane) (PDMS), operates similarly to an HPLC injection valve. It contains a channel segment (chamber) with a well-defined volume that serves as an "injection loop". Using on-chip microvalves, the chamber can be connected to the sample source during the "loading" step, and to the CE separation channel during the "injection" step. Once the valves are opened in the second state, electrophoretic potential is applied to separate the sample. For evaluation and demonstration purposes, the microinjector was connected to a 75 μm ID capillary and UV absorbance detector. For single compounds, a relative standard deviation (RSD) of peak area as low as 1.04% (n = 11) was obtained, and for compound mixtures, RSD as low as 0.40% (n = 4) was observed. Using the same microchip, the performance of this new injection technique was compared to hydrodynamic injection and found to have improved repeatability and less dependence on sample viscosity. Furthermore, a non-radioactive version of the positron-emission tomography (PET) imaging probe, FLT, was successfully separated from its known 3 structurally-similar byproducts with baseline resolution, demonstrating the potential for rapid, quantitative analysis of impurities to ensure the safety of batches of short-lived radiotracers. Both the separation efficiency and injection repeatability were found to be substantially higher when using the novel volumetric injection approach compared to electrokinetic injection (performed in the same chip). This novel microinjector provides a straightforward way to improve the performance of hydrodynamic injection and enables extremely repeatable sample volume injection in MCE. It could be used in any MCE application where volume repeatability is needed, including the quantitation of impurities in pharmaceutical or radiopharmaceutical samples.
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17
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Wuethrich A, Quirino JP. Sensitivity enhancing injection from a sample reservoir and channel interface in microchip electrophoresis. J Sep Sci 2017; 40:927-932. [DOI: 10.1002/jssc.201601064] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 11/08/2016] [Accepted: 11/28/2016] [Indexed: 11/09/2022]
Affiliation(s)
- Alain Wuethrich
- Australian Centre for Research on Separation Science (ACROSS) School of Physical Sciences‐Chemistry University of Tasmania Hobart TAS 7001 Australia
| | - Joselito P. Quirino
- Australian Centre for Research on Separation Science (ACROSS) School of Physical Sciences‐Chemistry University of Tasmania Hobart TAS 7001 Australia
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18
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Gabriel EF, dos Santos RA, Lobo-Júnior EO, Rezende KC, Coltro WK. Hydrodynamic injection on electrophoresis microchips using an electronic micropipette. Talanta 2017; 162:19-23. [DOI: 10.1016/j.talanta.2016.09.046] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 09/16/2016] [Accepted: 09/17/2016] [Indexed: 01/06/2023]
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19
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Ha JW, Hahn JH. Acupuncture injection for field amplified sample stacking and glass microchip-based capillary gel electrophoresis. Electrophoresis 2016; 38:521-524. [DOI: 10.1002/elps.201600469] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 11/04/2016] [Accepted: 11/05/2016] [Indexed: 11/08/2022]
Affiliation(s)
- Ji Won Ha
- Department of Chemistry; University of Ulsan; Ulsan South Korea
| | - Jong Hoon Hahn
- Department of Chemistry, BioNanotechnology Center; Pohang University of Science and Technology; Pohang South Korea
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Ali I, Alharbi OML, Marsin Sanagi M. Nano-capillary electrophoresis for environmental analysis. ENVIRONMENTAL CHEMISTRY LETTERS 2015; 14:79-98. [PMID: 32214934 PMCID: PMC7087629 DOI: 10.1007/s10311-015-0547-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 12/11/2015] [Indexed: 06/10/2023]
Abstract
Many analytical techniques have been used to monitor environmental pollutants. But most techniques are not capable to detect pollutants at nanogram levels. Hence, under such conditions, absence of pollutants is often assumed, whereas pollutants are in fact present at low but undetectable concentrations. Detection at low levels may be done by nano-capillary electrophoresis, also named microchip electrophoresis. Here, we review the analysis of pollutants by nano-capillary electrophoresis. We present instrumentations, applications, optimizations and separation mechanisms. We discuss the analysis of metal ions, pesticides, polycyclic aromatic hydrocarbons, explosives, viruses, bacteria and other contaminants. Detectors include ultraviolet-visible, fluorescent, conductivity, atomic absorption spectroscopy, refractive index, atomic fluorescence spectrometry, atomic emission spectroscopy, inductively coupled plasma, inductively coupled plasma-mass spectrometry, mass spectrometry, time-of-flight mass spectrometry and nuclear magnetic resonance. Detection limits ranged from nanogram to picogram levels.
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Affiliation(s)
- Imran Ali
- Department of Chemistry, Jamia Millia Islamia (Central University), New Delhi, 110025 India
| | - Omar M. L. Alharbi
- Biology Department, Faculty of Sciences, Taibah University, P.O. Box 30002, Madinah Al-Munawarah, 41477 Saudi Arabia
| | - Mohd. Marsin Sanagi
- Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia (UTM), 81310 Johor Bahru, Johor Malaysia
- Ibnu Sina Institute for Fundamental Science Studies, Nanotechnology Research Alliance, Universiti Teknologi Malaysia (UTM), 81310 Johor Bahru, Johor Malaysia
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21
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Koczka PI, Bodoki E, Gáspár A. Application of capacitively coupled contactless conductivity as an external detector for zone electrophoresis in poly(dimethylsiloxane) chips. Electrophoresis 2015; 37:398-405. [DOI: 10.1002/elps.201500335] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 10/16/2015] [Accepted: 10/20/2015] [Indexed: 01/06/2023]
Affiliation(s)
- Péter I. Koczka
- Department of Inorganic and Analytical Chemistry; University of Debrecen; Debrecen Hungary
| | - Ede Bodoki
- Department of Analytical Chemistry; “Iuliu Hatieganu” University of Medicine and Pharmacy; Cluj Napoca Romania
| | - Attila Gáspár
- Department of Inorganic and Analytical Chemistry; University of Debrecen; Debrecen Hungary
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Štěpánová S, Kašička V. Recent developments and applications of capillary and microchip electrophoresis in proteomic and peptidomic analyses. J Sep Sci 2015; 39:198-211. [DOI: 10.1002/jssc.201500973] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2015] [Revised: 10/06/2015] [Accepted: 10/06/2015] [Indexed: 12/19/2022]
Affiliation(s)
- Sille Štěpánová
- Institute of Organic Chemistry and Biochemistry; The Czech Academy of Sciences; Prague Czech Republic
| | - Václav Kašička
- Institute of Organic Chemistry and Biochemistry; The Czech Academy of Sciences; Prague Czech Republic
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23
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Cong Y, Katipamula S, Geng T, Prost SA, Tang K, Kelly RT. Electrokinetic sample preconcentration and hydrodynamic sample injection for microchip electrophoresis using a pneumatic microvalve. Electrophoresis 2015; 37:455-62. [PMID: 26255610 DOI: 10.1002/elps.201500286] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Revised: 07/23/2015] [Accepted: 07/24/2015] [Indexed: 12/11/2022]
Abstract
A microfluidic platform was developed to perform online electrokinetic sample preconcentration and rapid hydrodynamic sample injection for zone electrophoresis using a single microvalve. The polydimethylsiloxane microchip comprises a separation channel, a side channel for sample introduction, and a control channel which is used as a pneumatic microvalve aligned at the intersection of the two flow channels. The closed microvalve, created by multilayer soft lithography, serves as a nanochannel preconcentrator under an applied electric potential, enabling current to pass through while preventing bulk flow. Once analytes are concentrated, the valve is briefly opened and the stacked sample is pressure injected into the separation channel for electrophoretic separation. Fluorescently labeled peptides were enriched by a factor of ∼450 in 230 s. This method enables both rapid analyte concentration and controlled injection volume for high sensitivity, high-resolution CE.
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Affiliation(s)
- Yongzheng Cong
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Shanta Katipamula
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Tao Geng
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Spencer A Prost
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Keqi Tang
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, USA
| | - Ryan T Kelly
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, USA
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24
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Sahore V, Kumar S, Rogers CI, Jensen JK, Sonker M, Woolley AT. Pressure-actuated microfluidic devices for electrophoretic separation of pre-term birth biomarkers. Anal Bioanal Chem 2015; 408:599-607. [PMID: 26537925 DOI: 10.1007/s00216-015-9141-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 10/07/2015] [Accepted: 10/21/2015] [Indexed: 12/13/2022]
Abstract
We have developed microfluidic devices with pressure-driven injection for electrophoretic analysis of amino acids, peptides, and proteins. The novelty of our approach lies in the use of an externally actuated on-chip peristaltic pump and closely spaced pneumatic valves that allow well-defined, small-volume sample plugs to be injected and separated by microchip electrophoresis. We fabricated three-layer poly(dimethylsiloxane) (PDMS) microfluidic devices. The fluidic layer had injection and separation channels, and the control layer had an externally actuated on-chip peristaltic pump and four pneumatic valves around the T-intersection to carry out sample injection. An unpatterned PDMS membrane layer was sandwiched between the fluidic and control layers as the actuated component in pumps and valves. Devices with the same peristaltic pump design but different valve spacings (100, 200, 300, and 400 μm) from the injection intersection were fabricated using soft lithographic techniques. Devices were characterized through fluorescent imaging of captured plugs of a fluorescein-labeled amino acid mixture and through microchip electrophoresis separations. A suitable combination of peak height, separation efficiency, and analysis time was obtained with a peristaltic pump actuation rate of 50 ms, an injection time of 30 s, and a 200-μm valve spacing. We demonstrated the injection of samples in different solutions and were able to achieve a 2.4-fold improvement in peak height and a 2.8-fold increase in separation efficiency though sample stacking. A comparison of pressure-driven injection and electrokinetic injection with the same injection time and separation voltage showed a 3.9-fold increase in peak height in pressure-based injection with comparable separation efficiency. Finally, the microchip systems were used to separate biomarkers implicated in pre-term birth. Although these devices have initially been demonstrated as a stand-alone microfluidic separation tool, they have strong potential to be integrated within more complex systems.
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Affiliation(s)
- V Sahore
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, USA.
| | - S Kumar
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, USA.
| | - C I Rogers
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, USA.
| | - J K Jensen
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, USA.
| | - M Sonker
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, USA.
| | - A T Woolley
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT, USA.
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25
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Makrlíková A, Opekar F, Tůma P. Pressure-assisted introduction of urine samples into a short capillary for electrophoretic separation with contactless conductivity and UV spectrometry detection. Electrophoresis 2015; 36:1962-8. [DOI: 10.1002/elps.201400613] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Revised: 02/10/2015] [Accepted: 02/10/2015] [Indexed: 12/16/2022]
Affiliation(s)
- Anna Makrlíková
- Department of Analytical Chemistry; Faculty of Science, Charles University in Prague; Prague Czech Republic
| | - František Opekar
- Department of Analytical Chemistry; Faculty of Science, Charles University in Prague; Prague Czech Republic
| | - Petr Tůma
- Institute of Biochemistry Cell and Molecular Biology; Third Faculty of Medicine, Charles University in Prague; Prague Czech Republic
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26
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García-Otero N, Barciela-Alonso MC, Domínguez-González R, Herbello-Hermelo P, Moreda-Piñeiro A, Bermejo-Barrera P. Evaluation of offgel electrophoresis, electrothermal atomic absorption spectroscopy and inductively coupled plasma optical emission spectroscopy for trace metal analysis in marine plankton protein. Microchem J 2015. [DOI: 10.1016/j.microc.2014.11.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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27
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Bidulock ACE, van den Berg A, Eijkel JCT. Improving chip-to-chip precision in disposable microchip capillary electrophoresis devices with internal standards. Electrophoresis 2015; 36:875-83. [PMID: 25522336 DOI: 10.1002/elps.201400399] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Revised: 12/09/2014] [Accepted: 12/09/2014] [Indexed: 01/31/2023]
Abstract
To realize portable systems for routine measurements in point-of-care settings, MCE methods are required to be robust across many single-use chips. While it is well-known internal standards (ISTDs) improve run-to-run precision, a systematic investigation is necessary to determine the significance of chip-to-chip imprecision in MCE and how ISTDs account for it. This paper addresses this question by exploring the reproducibility of Na quantification across six basic, in-house fabricated microchips. A dataset of 900 electrophoerograms was collected from analyzing five concentrations of NaCl with two ISTDs (CsCl and LiCl). While both improved the peak area reproducibility, the Na/Cs ratio was superior to the Na/Li ratio (improving the RSD by a factor of 2-4, depending on the Na concentration). We attribute this to the significant variation in microchannel surface properties, which was accounted for by cesium but not lithium. Microchip dimension and detector variations were only a few percent, and could be improved through commercial fabrication over in-house made microchips. These results demonstrate that ISTDs not only correct for intrachip imprecision, but are also a viable means to correct for chip-to-chip imprecision inherent in disposable, point-of-care MCE devices. However, as expected, the internal standard must be carefully chosen.
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Affiliation(s)
- Allison C E Bidulock
- BIOS/The Lab-on-a-Chip Group, MESA + Institute for Nanotechnology and MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente Twente, The Netherlands
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28
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Saylor RA, Lunte SM. A review of microdialysis coupled to microchip electrophoresis for monitoring biological events. J Chromatogr A 2015; 1382:48-64. [PMID: 25637011 DOI: 10.1016/j.chroma.2014.12.086] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2014] [Revised: 12/23/2014] [Accepted: 12/26/2014] [Indexed: 12/30/2022]
Abstract
Microdialysis is a powerful sampling technique that enables monitoring of dynamic processes in vitro and in vivo. The combination of microdialysis with chromatographic or electrophoretic methods with selective detection yields a "separation-based sensor" capable of monitoring multiple analytes in near real time. For monitoring biological events, analysis of microdialysis samples often requires techniques that are fast (<1 min), have low volume requirements (nL-pL), and, ideally, can be employed on-line. Microchip electrophoresis fulfills these requirements and also permits the possibility of integrating sample preparation and manipulation with detection strategies directly on-chip. Microdialysis coupled to microchip electrophoresis has been employed for monitoring biological events in vivo and in vitro. This review discusses technical considerations for coupling microdialysis sampling and microchip electrophoresis, including various interface designs, and current applications in the field.
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Affiliation(s)
- Rachel A Saylor
- Department of Chemistry, University of Kansas, Lawrence, KS 66045, USA; Ralph N. Adams Institute for Bioanalytical Chemistry, University of Kansas, Lawrence, KS 66047, USA.
| | - Susan M Lunte
- Department of Chemistry, University of Kansas, Lawrence, KS 66045, USA; Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS 66047, USA; Ralph N. Adams Institute for Bioanalytical Chemistry, University of Kansas, Lawrence, KS 66047, USA.
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29
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Present state of microchip electrophoresis: state of the art and routine applications. J Chromatogr A 2014; 1382:66-85. [PMID: 25529267 DOI: 10.1016/j.chroma.2014.11.034] [Citation(s) in RCA: 130] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 11/07/2014] [Accepted: 11/12/2014] [Indexed: 12/20/2022]
Abstract
Microchip electrophoresis (MCE) was one of the earliest applications of the micro-total analysis system (μ-TAS) concept, whose aim is to reduce analysis time and reagent and sample consumption while increasing throughput and portability by miniaturizing analytical laboratory procedures onto a microfluidic chip. More than two decades on, electrophoresis remains the most common separation technique used in microfluidic applications. MCE-based instruments have had some commercial success and have found application in many disciplines. This review will consider the present state of MCE including recent advances in technology and both novel and routine applications in the laboratory. We will also attempt to assess the impact of MCE in the scientific community and its prospects for the future.
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30
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Kelly RT, Wang C, Rausch SJ, Lee CS, Tang K. Pneumatic microvalve-based hydrodynamic sample injection for high-throughput, quantitative zone electrophoresis in capillaries. Anal Chem 2014; 86:6723-9. [PMID: 24865952 PMCID: PMC4082392 DOI: 10.1021/ac501910p] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
A hybrid microchip/capillary electrophoresis (CE) system was developed to allow unbiased and lossless sample loading and high-throughput repeated injections. This new hybrid CE system consists of a poly(dimethylsiloxane) (PDMS) microchip sample injector featuring a pneumatic microvalve that separates a sample introduction channel from a short sample loading channel, and a fused-silica capillary separation column that connects seamlessly to the sample loading channel. The sample introduction channel is pressurized such that when the pneumatic microvalve opens briefly, a variable-volume sample plug is introduced into the loading channel. A high voltage for CE separation is continuously applied across the loading channel and the fused-silica capillary separation column. Analytes are rapidly separated in the fused-silica capillary, and following separation, high-sensitivity MS detection is accomplished via a sheathless CE/ESI-MS interface. The performance evaluation of the complete CE/ESI-MS platform demonstrated that reproducible sample injection with well controlled sample plug volumes could be achieved by using the PDMS microchip injector. The absence of band broadening from microchip to capillary indicated a minimum dead volume at the junction. The capabilities of the new CE/ESI-MS platform in performing high-throughput and quantitative sample analyses were demonstrated by the repeated sample injection without interrupting an ongoing separation and a linear dependence of the total analyte ion abundance on the sample plug volume using a mixture of peptide standards. The separation efficiency of the new platform was also evaluated systematically at different sample injection times, flow rates, and CE separation voltages.
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Affiliation(s)
- Ryan T Kelly
- Environmental Molecular Sciences Laboratory and §Biological Sciences Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, United States
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31
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Gaudry AJ, Nai YH, Guijt RM, Breadmore MC. Polymeric Microchip for the Simultaneous Determination of Anions and Cations by Hydrodynamic Injection Using a Dual-Channel Sequential Injection Microchip Electrophoresis System. Anal Chem 2014; 86:3380-8. [DOI: 10.1021/ac403627g] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Adam J. Gaudry
- Australian Centre
for Research on Separation Science, School of Physical Sciences: Chemistry,
Faculty of Science Engineering and Technology, University of Tasmania, Private
Bag 75, Hobart, Tasmania, 7001, Australia
| | - Yi Heng Nai
- Australian Centre
for Research on Separation Science, School of Physical Sciences: Chemistry,
Faculty of Science Engineering and Technology, University of Tasmania, Private
Bag 75, Hobart, Tasmania, 7001, Australia
| | - Rosanne M. Guijt
- Australian Centre
for Research on Separation Science, Pharmacy School of Medicine, Faculty
of Health Science, University of Tasmania, Private Bag 26, Hobart, Tasmania, 7001, Australia
| | - Michael C. Breadmore
- Australian Centre
for Research on Separation Science, School of Physical Sciences: Chemistry,
Faculty of Science Engineering and Technology, University of Tasmania, Private
Bag 75, Hobart, Tasmania, 7001, Australia
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32
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Portugal LA, Laglera LM, Anthemidis AN, Ferreira SL, Miró M. Pressure-driven mesofluidic platform integrating automated on-chip renewable micro-solid-phase extraction for ultrasensitive determination of waterborne inorganic mercury. Talanta 2013; 110:58-65. [DOI: 10.1016/j.talanta.2013.02.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Revised: 01/25/2013] [Accepted: 02/05/2013] [Indexed: 10/27/2022]
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33
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García-Otero N, Peña-Vázquez E, Barciela-Alonso MC, Bermejo-Barrera P, Moreda-Piñeiro A. Two-Dimensional Isoelectric Focusing OFFGEL and Microfluidic Lab-on-Chip Electrophoresis for Assessing Dissolved Proteins in Seawater. Anal Chem 2013; 85:5909-16. [DOI: 10.1021/ac400669c] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Natalia García-Otero
- Department of Analytical Chemistry, Nutrition
and Bromatology, Faculty of Chemistry, University of Santiago de Compostela, Avenida das Ciencias, s/n.
15782, Santiago de Compostela, Spain
| | - Elena Peña-Vázquez
- Department of Analytical Chemistry, Nutrition
and Bromatology, Faculty of Chemistry, University of Santiago de Compostela, Avenida das Ciencias, s/n.
15782, Santiago de Compostela, Spain
| | - María Carmen Barciela-Alonso
- Department of Analytical Chemistry, Nutrition
and Bromatology, Faculty of Chemistry, University of Santiago de Compostela, Avenida das Ciencias, s/n.
15782, Santiago de Compostela, Spain
| | - Pilar Bermejo-Barrera
- Department of Analytical Chemistry, Nutrition
and Bromatology, Faculty of Chemistry, University of Santiago de Compostela, Avenida das Ciencias, s/n.
15782, Santiago de Compostela, Spain
| | - Antonio Moreda-Piñeiro
- Department of Analytical Chemistry, Nutrition
and Bromatology, Faculty of Chemistry, University of Santiago de Compostela, Avenida das Ciencias, s/n.
15782, Santiago de Compostela, Spain
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34
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Li X, Zhao S, Liu YM. Evaluation of a microchip electrophoresis-mass spectrometry platform deploying a pressure-driven make-up flow. J Chromatogr A 2013; 1285:159-64. [PMID: 23473508 PMCID: PMC3602291 DOI: 10.1016/j.chroma.2013.02.031] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 02/04/2013] [Accepted: 02/05/2013] [Indexed: 01/27/2023]
Abstract
Integration of a pressure-driven make-up flow (MUF) into a microchip electrophoresis (MCE) platform in order to facilitate its coupling with electrospray ionization-mass spectrometric detection (ESI-MS) is described. In the glass/PDMS hybrid microchip, a MUF channel was made to intersect with the MCE separation channel at an angle of 45°. The MUF was generated by a syringe pump. Microscopic image results from simulation studies showed that the pressure-driven MUF and the potential-driven electroosmotic flow in the MCE separation channel could be run separately without interfering with each other and mixed well at the joint point by adjusting either the MUF flow rate or the potential applied for MCE separation. The MUF had several desirable functions, including making the start of electrospray easy and cleaning the nanoESI emitter continuously when not spraying. High separation efficiency was achieved with the proposed MCE-nanoESI-MS system in separating an amino acid mixture containing glutamine, serine, threonine, phenylalanine, and glutamic acid. All of them were baseline separated from each other within 3 min. Plate numbers of >10,000 (on a 2.5 cm MCE separation channel) were obtained. The analytical platform also showed a linear response for quantification of DOPA with a detection limit (S/N=3) of 0.10 μM. In addition, on-line derivatization of MCE elutes in order to enhance MS detection sensitivity was easily carried out by adding the tagging reagent into the MUF. These results indicated that the present system might have a good potential in MCE-MS applications.
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Affiliation(s)
- Xiangtang Li
- Department of Chemistry and Biochemistry, Jackson State University, 1400 Lynch St., Jackson, MS, 39217
| | - Shulin Zhao
- Department of Chemistry and Biochemistry, Jackson State University, 1400 Lynch St., Jackson, MS, 39217
- College of Chemistry and Chemical Engineering, Guangxi Normal University, Guilin, 51004, China
| | - Yi-Ming Liu
- Department of Chemistry and Biochemistry, Jackson State University, 1400 Lynch St., Jackson, MS, 39217
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35
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Recent advances in microchip electrophoresis for amino acid analysis. Anal Bioanal Chem 2013; 405:7907-18. [DOI: 10.1007/s00216-013-6830-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2012] [Revised: 01/25/2013] [Accepted: 02/07/2013] [Indexed: 12/27/2022]
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36
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Simultaneous analysis of seven oligopeptides in microbial fuel cell by micro-fluidic chip with reflux injection mode. Talanta 2012; 100:338-43. [DOI: 10.1016/j.talanta.2012.07.079] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Revised: 07/26/2012] [Accepted: 07/30/2012] [Indexed: 01/25/2023]
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