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Kovář P, Tichý D, Slouka Z. Effect of channel geometry on ion-concentration polarization-based preconcentration and desalination. BIOMICROFLUIDICS 2019; 13:064102. [PMID: 31700561 PMCID: PMC6824913 DOI: 10.1063/1.5124787] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 10/11/2019] [Indexed: 06/10/2023]
Abstract
Polarization of the ion-selective systems results in the formation of ion-depleted and ion-concentrated zones in the electrolyte layers adjacent to the system. One can employ ion-concentration polarization for the removal of charged large molecules and small ions from the flowing liquid. Removal of large molecules from the flowing solution and their local accumulation is often referred to as preconcentration, removal of small ions as desalination. Here, we study the effect of the channel geometry on the removal of charged species from their water solutions experimentally. Straight, converging, and diverging channels equipped with a pair of heterogeneous cation-exchange membranes are compared in terms of their effect on preconcentration of an observable fluorescein dye and on desalination of water solution of potassium chloride. Our results show that preconcentration of the dye is not significantly affected by the channel geometry. The distance of the preconcentration band from one of the membranes was approximately the same in all tested channel geometries. The major difference was in the location of the band within the channel, when the conical channels localized the band at one of the channel walls. The straight channel showed a slightly broader range of applicable flow rates. The semibatch desalination of 0.01M KCl solution turned out to be more efficient in conical channels, which was associated with a larger volume of the channel available for the accumulation of the concentrated solution. Our results suggest that conical channels can be advantageously used in transforming the ion-concentration-polarization-based semibatch desalination into a fully continuous one.
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Affiliation(s)
- Petr Kovář
- Department of Chemical Engineering, University of Chemistry and Technology Prague, Technická 3, Prague 6 16628, Czech Republic
| | - David Tichý
- Department of Chemical Engineering, University of Chemistry and Technology Prague, Technická 3, Prague 6 16628, Czech Republic
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2
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Quist J, Vulto P, Hankemeier T. Isotachophoretic Phenomena in Electric Field Gradient Focusing: Perspectives for Sample Preparation and Bioassays. Anal Chem 2014; 86:4078-87. [DOI: 10.1021/ac403764e] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Jos Quist
- Division of Analytical Biosciences, Leiden
Academic Centre for Drug Research (LACDR), Gorlaeus Laboratories, Einsteinweg 55, Leiden, 2333CC, The Netherlands
- Netherlands Metabolomics
Centre (NMC), Leiden University, Einsteinweg 55, Leiden, South Holland 2333CC, The Netherlands
| | - Paul Vulto
- Division of Analytical Biosciences, Leiden
Academic Centre for Drug Research (LACDR), Gorlaeus Laboratories, Einsteinweg 55, Leiden, 2333CC, The Netherlands
- Netherlands Metabolomics
Centre (NMC), Leiden University, Einsteinweg 55, Leiden, South Holland 2333CC, The Netherlands
| | - Thomas Hankemeier
- Division of Analytical Biosciences, Leiden
Academic Centre for Drug Research (LACDR), Gorlaeus Laboratories, Einsteinweg 55, Leiden, 2333CC, The Netherlands
- Netherlands Metabolomics
Centre (NMC), Leiden University, Einsteinweg 55, Leiden, South Holland 2333CC, The Netherlands
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3
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Landreh M, Astorga-Wells J, Johansson J, Bergman T, Jörnvall H. New developments in protein structure-function analysis by MS and use of hydrogen-deuterium exchange microfluidics. FEBS J 2011; 278:3815-21. [DOI: 10.1111/j.1742-4658.2011.08215.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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4
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Breadmore MC, Dawod M, Quirino JP. Recent advances in enhancing the sensitivity of electrophoresis and electrochromatography in capillaries and microchips (2008-2010). Electrophoresis 2010; 32:127-48. [PMID: 21171119 DOI: 10.1002/elps.201000412] [Citation(s) in RCA: 129] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2010] [Revised: 09/15/2010] [Accepted: 09/16/2010] [Indexed: 01/22/2023]
Abstract
Capillary electrophoresis has been alive for over two decades now; yet, its sensitivity is still regarded as being inferior to that of more traditional methods of separation such as HPLC. As such, it is unsurprising that overcoming this issue still generates much scientific interest. This review continues to update this series of reviews, first published in Electrophoresis in 2007, with an update published in 2009 and covers material published through to June 2010. It includes developments in the fields of stacking, covering all methods from field-amplified sample stacking and large volume sample stacking, through to ITP, dynamic pH junction and sweeping. Attention is also given to on-line or in-line extraction methods that have been used for electrophoresis.
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Affiliation(s)
- Michael C Breadmore
- Australian Centre for Research on Separation Science, School of Chemistry, University of Tasmania, Hobart, TAS, Australia.
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5
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Trends in the bioanalytical applications of microfluidic electrocapture. Anal Bioanal Chem 2010; 399:191-5. [DOI: 10.1007/s00216-010-4092-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2010] [Revised: 08/02/2010] [Accepted: 08/03/2010] [Indexed: 11/26/2022]
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6
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Zhou Y, Shen H, Yi T, Wen D, Pang N, Liao J, Liu H. Synergistic design of electric field and membrane in facilitating continuous adsorption for cleanup and enrichment of proteins in direct ESI-MS analysis. Anal Chem 2009; 80:8920-9. [PMID: 18954078 DOI: 10.1021/ac800816k] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We designed and fabricated a novel microdevice to facilitate continuous adsorption phenomena for biological sample preparation. Using the device, we also developed an online, highly integrated, multifunctional strategy, with a promise of accepting a large volume of crude tissue extracts with the end point generation of a reliable MS identification within 20 min. Under an external electric field, charged membranes can adsorb multiple layers of proteins, which exceed the capacity limit of common resins or membranes. It enlarges sample loading and trapping efficiency, thus bypasses the tradeoff between sample capacity and downstream detection sensitivity. This integrated approach, formed by synergistic utilization among electric field, membrane, and fluidic handling at the microscale, reduces the overall complexity of crude samples in one step for direct MS analysis. The sample preparation goals, including enrichment, desalting, removal of noncharged contaminants, and initial fractionation, can be rapidly performed in a single device. The strategy facilitates reproducible MS quantification by circumventing traditional laborious and time-consuming sample preparation steps. In addition, MEPD extended the ion trap linear dynamic range from 2 to at least 4 orders of magnitude by eliminating ion suppression effect, enriching target analyte(s), and decreasing sample loss during integrated sample preparation.
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Affiliation(s)
- Yu Zhou
- Beijing National Laboratory for Molecular Sciences, Key Lab of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Inst. of Analytical Chemistry, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
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7
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Meighan MM, Staton SJR, Hayes MA. Bioanalytical separations using electric field gradient techniques. Electrophoresis 2009; 30:852-65. [DOI: 10.1002/elps.200800614] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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8
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Shariatgorji M, Astorga-Wells J, Jörnvall H, Ilag LL. Microfluidic Electrocapture-Assisted Mass Spectrometry of Membrane-Associated Polypeptides. Anal Chem 2008; 80:7116-20. [DOI: 10.1021/ac800877k] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Mohammadreza Shariatgorji
- Department of Analytical Chemistry, Stockholm University,
SE-106 91 Stockholm, Sweden, and Department of Medical Biochemistry
and Biophysics, Chemistry I, Karolinska Institute, SE-171 77 Stockholm,
Sweden
| | - Juan Astorga-Wells
- Department of Analytical Chemistry, Stockholm University,
SE-106 91 Stockholm, Sweden, and Department of Medical Biochemistry
and Biophysics, Chemistry I, Karolinska Institute, SE-171 77 Stockholm,
Sweden
| | - Hans Jörnvall
- Department of Analytical Chemistry, Stockholm University,
SE-106 91 Stockholm, Sweden, and Department of Medical Biochemistry
and Biophysics, Chemistry I, Karolinska Institute, SE-171 77 Stockholm,
Sweden
| | - Leopold L. Ilag
- Department of Analytical Chemistry, Stockholm University,
SE-106 91 Stockholm, Sweden, and Department of Medical Biochemistry
and Biophysics, Chemistry I, Karolinska Institute, SE-171 77 Stockholm,
Sweden
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9
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Lin H, Shackman JG, Ross D. Finite sample effect in temperature gradient focusing. LAB ON A CHIP 2008; 8:969-978. [PMID: 18497919 DOI: 10.1039/b713749d] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Temperature gradient focusing (TGF) is a new and promising equilibrium gradient focusing method which can provide high concentration factors for improved detection limits in combination with high-resolution separation. In this technique, temperature-dependent buffer chemistry is employed to generate a gradient in the analyte electrophoretic velocity. By the application of a convective counter-flow, a zero-velocity point is created within a microchannel, at which location the ionic analytes accumulate or focus. In general, the analyte concentration is small when compared with buffer ion concentrations, such that the focusing mechanism works in the ideal, linearized regime. However, this presumption may at times be violated due to significant sample concentration growth or the use of a low-concentration buffer. Under these situations the sample concentration becomes non-negligible and can induce strong nonlinear interactions with buffer ions, which eventually lead to peak shifting and distortion, and the loss of detectability and resolution. In this work we combine theory, simulation, and experimental data to present a detailed study on nonlinear sample-buffer interactions in TGF. One of the key results is the derivation of a generalized Kohlrausch regulating function (KRF) that is valid for systems in which the electrophoretic mobilities are not constant but vary spatially. This generalized KRF greatly facilitates analysis, allowing reduction of the problem to a single equation describing sample concentration evolution, and is applicable to other problems with heterogeneous electrophoretic mobilities. Using this sample evolution equation we have derived an understanding of the nonlinear peak deformation phenomenon observed experimentally in TGF. We have used numerical simulations to validate our theory and to quantitatively predict TGF. Our simulation results demonstrate excellent agreement with experimental data, and also indicate that the proper inclusion of Taylor dispersion is important for the accurate modeling of TGF. This work is an important first step towards the understanding and prediction of the more complex, nonlinear, and multi-species interactions which often occur in on-chip electrophoretic assays such as TGF.
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Affiliation(s)
- Hao Lin
- Mechanical & Aerospace Engineering, Rutgers, The State University of New Jersey, 98 Brett Rd, Piscataway, NJ 08854, USA.
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10
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Nesbitt CA, Jurcic K, Yeung KKC. Nanoliter-volume protein enrichment, tryptic digestion, and partial separation based on isoelectric points by CE for MALDI mass spectral analysis. Electrophoresis 2008; 29:466-74. [DOI: 10.1002/elps.200700339] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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11
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Breadmore MC. Recent advances in enhancing the sensitivity of electrophoresis and electrochromatography in capillaries and microchips. Electrophoresis 2007; 28:254-81. [PMID: 17149782 DOI: 10.1002/elps.200600463] [Citation(s) in RCA: 160] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Poor sensitivity is considered to be one of the major limitations of electrophoretic separation methods, particularly when compared to traditional liquid chromatographic techniques. To address this issue, various in-line preconcentration techniques have been developed over the past 15 years, ranging in power and complexity, and there are now a number of well understood approaches routinely capable of providing a 10,000- to 100,000-fold increase in sensitivity, as well as several that can be pushed above a million. Furthermore, these have been achieved with particularly troublesome and often difficult samples, such as those having high salinity from a biological or environmental origin. This review will discuss the most common methods for improving the sensitivity of CE, CEC and microchip version of these, with particular attention to those approaches developed over the last five years.
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Affiliation(s)
- Michael C Breadmore
- Australian Centre for Research on Separation Science, School of Chemistry, University of Tasmania, Hobart, Tasmania, Australia.
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12
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Abstract
Counter-flow gradient electrofocusing techniques are methods whereby a combination of electrophoresis and a bulk solution counter-flow is used to accumulate or focus analytes at stationary points along a separation column. This review first describes the various forms of counter-flow gradient electrofocusing that have been demonstrated in the literature and then compares figures of merit for counter-flow focusing methods and conventional CE methods. In an effort to compare the concentration enhancement of the various focusing techniques against each other, as well as of stacking methods, the parameter of analyte-accumulation velocity is introduced and employed to normalize the efficacy of the techniques.
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Affiliation(s)
- Jonathan G Shackman
- National Institute of Standards & Technology, Gaithersburg, MD 20899-8311, USA
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13
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Astorga-Wells J, Vollmer S, Bergman T, Jörnvall H. Formation of Stable Stacking Zones in a Flow Stream for Sample Immobilization in Microfluidic Systems. Anal Chem 2007; 79:1057-63. [PMID: 17263335 DOI: 10.1021/ac061699f] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Electrocapture is a multifunctional microfluidic tool that can be used for concentration, sample cleanup, multistep reactions, and separation of biomolecules. Herein, we investigate the mechanisms underlying the electrocapture principle. A microfluidic electrocapture device was found to be capable of generating regions of different electric field, which are maintained in the flow by electric and hydrodynamic forces, with the zones of lower electric field strength upstream of those with higher strength. In addition to detection of the local electric fields by direct measurements, the existence of the zones was observed by the capture of a solution containing Coomassie and myoglobin. The two molecules were captured at different spots in a steady-state manner and were released (separated) at different electric fields. Considering these observations and the experimental values for the electric field strengths, flow velocities, and electrophoretic mobilities of DNA, proteins, and peptides, it is concluded that the macromolecules are captured between the field zones by a stacking mechanism.
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Affiliation(s)
- Juan Astorga-Wells
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden
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14
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Astorga-Wells J, Vollmer S, Tryggvason S, Bergman T, Jörnvall H. Microfluidic Electrocapture for Separation of Peptides. Anal Chem 2005; 77:7131-6. [PMID: 16285658 DOI: 10.1021/ac050931z] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A separation method based on electroimmobilization and sequential release of captured molecules is reported. A microfluidic electrocapture device is utilized to immobilize peptides in a microflow stream. After capture, the electric field is decreased in a stepwise manner, causing sequential release of the captured peptides according to their electrophoretic mobility. Tryptic peptides were separated and analyzed by matrix-assisted laser desorption/ionization mass spectrometry. The separation power was high enough to increase the ionization yield of several peptides not seen in the unprocessed sample. In addition to separation, simultaneous sample cleanup was demonstrated for peptides obtained by shotgun tryptic digestion of membrane protein extracts.
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Affiliation(s)
- Juan Astorga-Wells
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
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15
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Astorga-Wells J, Vollmer S, Bergman T, Jörnvall H. Microfluidic systems and proteomics: Applications of the electrocapture technology to protein and peptide analysis. Anal Biochem 2005; 345:10-7. [PMID: 15993835 DOI: 10.1016/j.ab.2005.04.049] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2005] [Revised: 04/20/2005] [Accepted: 04/23/2005] [Indexed: 11/17/2022]
Affiliation(s)
- Juan Astorga-Wells
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-17177 Stockholm, Sweden.
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16
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Slovakova M, Minc N, Bilkova Z, Smadja C, Faigle W, Fütterer C, Taverna M, Viovy JL. Use of self assembled magnetic beads for on-chip protein digestion. LAB ON A CHIP 2005; 5:935-42. [PMID: 16100577 DOI: 10.1039/b504861c] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The use of grafted trypsin magnetic beads in a microchip for performing protein digestion is described. The PDMS device uses strong magnets to create a magnetic field parallel to the flow with a strong gradient pointing through the center of the chip channel. This allows for the formation of a low-hydrodynamic resistance plug of magnetic trypsin beads that serves as a matrix for protein digestion. This device represents an inexpensive way of fabricating a multi open-tubular-like column with an appropriate pore size for proteins. Kinetics studies of the hydrolysis of a model peptide show a 100-fold increase in digestion speed obtained by the microsystem when compared to a batch wise system. This system also offers the great advantage of easy replacement, as the bead matrix is easily washed out and replaced. High performance and reproducibility for digesting recombinant human growth hormone are confirmed by analysing the digest products in both CE and MALDI-TOF MS. Similar sequence coverage (of about 44%) is obtained from MS analysis of products after 10 minutes on-chip and 4 h with soluble trypsin in bulk.
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Affiliation(s)
- Marcela Slovakova
- Laboratoire Physicochimie-Curie, UMR/CNRS 168, Institut Curie, 75248 Paris Cedex 5, France
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Hirschberg D, Tryggvason S, Gustafsson M, Bergman T, Swedenborg J, Hedin U, Jörnvall H. Identification of endothelial proteins by MALDI-MS using a compact disc microfluidic system. Protein J 2005; 23:263-71. [PMID: 15214497 DOI: 10.1023/b:jopc.0000027851.46123.4e] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Vascular endothelial proteins have been analyzed using two-dimensional (2D) gel electrophoresis and subsequent mass spectrometry, with separate methods for the intervening sample preparations. Compact disc (CD) technology was found to be rapid, giving high overall yield both with ordinary Coomassie staining and with Sypro Ruby staining. Combined with automatic in-gel digestion, the CD technology has great capacity for large numbers of protein analysis, although for limited sample numbers, manual methods can give similar sequence coverage. In a test set of 48 samples, 45 proteins were identified using the CD preparation technique, 32 identified with higher sequence coverage using the CD technique, 7 with higher using ZipTips in a robotic workstation, and 5 with higher coverage using dried droplets of unpurified samples. In the process of these methodological comparisons, basic patterns for 116 endothelial proteins were defined, representing 297 separate protein spots on the 2D gels.
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Affiliation(s)
- Daniel Hirschberg
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, SE-171 77 Stockholm, Sweden
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18
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Wheeler AR, Moon H, Bird CA, Loo RRO, Kim CJCJ, Loo JA, Garrell RL. Digital Microfluidics with In-Line Sample Purification for Proteomics Analyses with MALDI-MS. Anal Chem 2005; 77:534-40. [PMID: 15649050 DOI: 10.1021/ac048754+] [Citation(s) in RCA: 210] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
An in-line sample purification method for MALDI-MS, which relies on the electrowetting-on-dielectric (EWOD)-based technique for digital microfluidics, is reported. In this method, a droplet containing peptides and impurities is moved by EWOD and deposited onto a Teflon-AF surface. A droplet of water is subsequently moved over the spot, where it dissolves and removes the impurities. A droplet containing MALDI matrix is then moved to the spot, which is analyzed by MALDI-MS. This purification method reduces the number of salt adduct peaks caused by low concentrations of impurities (e.g., 20 mM sodium phosphate), and reduces or eliminates the catastrophic effects of high concentrations of impurities (e.g., 8 M urea). The method was used to purify spots made by depositing multiple droplets of contaminated peptides. Spectra from the purified spots showed an increase in the S/N ratio as a function of the number of droplets deposited; when not purified, the S/N ratio remained constant regardless of the number of droplets. Finally, the method was used to purify protein digests for peptide mass fragment (PMF) searches, and was shown to be more efficient than the conventional method of purification with reversed-phase-packed pipet tips. We anticipate this new, in-line sample purification technique for EWOD-MALDI-MS will enable development of integrated high-throughput proteomics analysis methodologies.
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Affiliation(s)
- Aaron R Wheeler
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569, USA
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