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Krebs F, Zagst H, Stein M, Ratih R, Minkner R, Olabi M, Hartung S, Scheller C, Lapizco-Encinas BH, Sänger-van de Griend C, García CD, Wätzig H. Strategies for capillary electrophoresis: Method development and validation for pharmaceutical and biological applications-Updated and completely revised edition. Electrophoresis 2023; 44:1279-1341. [PMID: 37537327 DOI: 10.1002/elps.202300158] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 07/19/2023] [Indexed: 08/05/2023]
Abstract
This review is in support of the development of selective, precise, fast, and validated capillary electrophoresis (CE) methods. It follows up a similar article from 1998, Wätzig H, Degenhardt M, Kunkel A. "Strategies for capillary electrophoresis: method development and validation for pharmaceutical and biological applications," pointing out which fundamentals are still valid and at the same time showing the enormous achievements in the last 25 years. The structures of both reviews are widely similar, in order to facilitate their simultaneous use. Focusing on pharmaceutical and biological applications, the successful use of CE is now demonstrated by more than 600 carefully selected references. Many of those are recent reviews; therefore, a significant overview about the field is provided. There are extra sections about sample pretreatment related to CE and microchip CE, and a completely revised section about method development for protein analytes and biomolecules in general. The general strategies for method development are summed up with regard to selectivity, efficiency, precision, analysis time, limit of detection, sample pretreatment requirements, and validation.
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Affiliation(s)
- Finja Krebs
- Institute, of Medicinal and Pharmaceutical Chemistry, Technische Universität Braunschweig, Braunschweig, Lower Saxony, Germany
| | - Holger Zagst
- Institute, of Medicinal and Pharmaceutical Chemistry, Technische Universität Braunschweig, Braunschweig, Lower Saxony, Germany
| | - Matthias Stein
- Institute, of Medicinal and Pharmaceutical Chemistry, Technische Universität Braunschweig, Braunschweig, Lower Saxony, Germany
| | - Ratih Ratih
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, University of Surabaya, Surabaya, East Java, Indonesia
| | - Robert Minkner
- Institute, of Medicinal and Pharmaceutical Chemistry, Technische Universität Braunschweig, Braunschweig, Lower Saxony, Germany
| | - Mais Olabi
- Institute, of Medicinal and Pharmaceutical Chemistry, Technische Universität Braunschweig, Braunschweig, Lower Saxony, Germany
| | - Sophie Hartung
- Institute, of Medicinal and Pharmaceutical Chemistry, Technische Universität Braunschweig, Braunschweig, Lower Saxony, Germany
| | - Christin Scheller
- Institute, of Medicinal and Pharmaceutical Chemistry, Technische Universität Braunschweig, Braunschweig, Lower Saxony, Germany
| | - Blanca H Lapizco-Encinas
- Department of Biomedical Engineering, Kate Gleason College of Engineering, Rochester Institute of Technology, Rochester, New York, USA
| | - Cari Sänger-van de Griend
- Kantisto BV, Baarn, The Netherlands
- Department of Medicinal Chemistry, Faculty of Pharmacy, Uppsala Universitet, Uppsala, Sweden
| | - Carlos D García
- Department of Chemistry, Clemson University, Clemson, South Carolina, USA
| | - Hermann Wätzig
- Institute, of Medicinal and Pharmaceutical Chemistry, Technische Universität Braunschweig, Braunschweig, Lower Saxony, Germany
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2
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Stutz H. Advances and applications of electromigration methods in the analysis of therapeutic and diagnostic recombinant proteins – A Review. J Pharm Biomed Anal 2022; 222:115089. [DOI: 10.1016/j.jpba.2022.115089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 09/28/2022] [Accepted: 09/29/2022] [Indexed: 11/29/2022]
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Abstract
Isotachophoresis (ITP) is a versatile electrophoretic technique that can be used for sample preconcentration, separation, purification, and mixing, and to control and accelerate chemical reactions. Although the basic technique is nearly a century old and widely used, there is a persistent need for an easily approachable, succinct, and rigorous review of ITP theory and analysis. This is important because the interest and adoption of the technique has grown over the last two decades, especially with its implementation in microfluidics and integration with on-chip chemical and biochemical assays. We here provide a review of ITP theory starting from physicochemical first-principles, including conservation of species, conservation of current, approximation of charge neutrality, pH equilibrium of weak electrolytes, and so-called regulating functions that govern transport dynamics, with a strong emphasis on steady and unsteady transport. We combine these generally applicable (to all types of ITP) theoretical discussions with applications of ITP in the field of microfluidic systems, particularly on-chip biochemical analyses. Our discussion includes principles that govern the ITP focusing of weak and strong electrolytes; ITP dynamics in peak and plateau modes; a review of simulation tools, experimental tools, and detection methods; applications of ITP for on-chip separations and trace analyte manipulation; and design considerations and challenges for microfluidic ITP systems. We conclude with remarks on possible future research directions. The intent of this review is to help make ITP analysis and design principles more accessible to the scientific and engineering communities and to provide a rigorous basis for the increased adoption of ITP in microfluidics.
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Affiliation(s)
- Ashwin Ramachandran
- Department
of Aeronautics and Astronautics, Stanford
University, Stanford, California 94305, United States
| | - Juan G. Santiago
- Department
of Mechanical Engineering, Stanford University, Stanford, California 94305, United States
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4
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Thormann W, Mosher RA. Instabilities of the pH gradient in carrier ampholyte-based isoelectric focusing: Elucidation of the contributing electrokinetic processes by computer simulation. Electrophoresis 2020; 42:814-833. [PMID: 33184847 DOI: 10.1002/elps.202000269] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 10/22/2020] [Accepted: 11/05/2020] [Indexed: 11/05/2022]
Abstract
Electrokinetic processes that lead to pH gradient instabilities in carrier ampholyte-based IEF are reviewed. In addition to electroosmosis, there are four of electrophoretic nature, namely (i) the stabilizing phase with the plateau phenomenon, (ii) the gradual isotachophoretic loss of carrier ampholytes at the two column ends in presence of electrode solutions, (iii) the inequality of the mobilities of positively and negatively charged species of ampholytes, and (iv) the continuous penetration of carbonate from the catholyte into the focusing column. The impact of these factors to cathodic and anodic drifts was analyzed by simulation of carrier ampholyte-based focusing in closed and open columns. Focusing under realistic conditions within a 5 cm long capillary in which three amphoteric low molecular mass dyes were focused in a pH 3-10 gradient formed by 140 carrier ampholytes was investigated. In open columns, electroosmosis displaces the entire gradient toward the cathode or anode whereas the electrophoretic processes act bidirectionally with a transition around pH 4 (drifts for pI > 4 and pI < 4 typically toward the cathode and anode, respectively). The data illustrate that focused zones of carrier ampholytes have an electrophoretic flux and that dynamic simulation can be effectively used to assess the magnitude of each of the electrokinetic destabilizing factors and the resulting drift for a combination of these effects. Predicted drifts of focused marker dyes are compared to those observed experimentally in a setup with coated capillary and whole column optical imaging.
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Affiliation(s)
- Wolfgang Thormann
- Institute for Infectious Diseases, University of Bern, Bern, Switzerland
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5
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Schmailzl J, Vorage MW, Stutz H. Intact and middle-down CIEF of commercial therapeutic monoclonal antibody products under non-denaturing conditions. Electrophoresis 2020; 41:1109-1117. [PMID: 32250465 PMCID: PMC7317833 DOI: 10.1002/elps.202000013] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 03/04/2020] [Accepted: 03/19/2020] [Indexed: 11/06/2022]
Abstract
A two‐step CIEF with chemical mobilization was developed for charge profiling of the therapeutic mAb rituximab under non‐denaturing separation conditions. CIEF of the intact mAb was combined with a middle‐down approach analyzing Fc/2 and F(ab´)2 fragments after digest with a commercial cysteine protease (IdeS). CIEF methods were optimized separately for the intact mAb and its fragments due to their divergent pIs. Best resolution was achieved by combining Pharmalyte (PL) 8–10.5 with PL 3–10 for variants of intact rituximab and of F(ab´)2 fragments, respectively, whereas PL 6.7–7.7 in combination with PL 3–10 was used for Fc/2 variants. Charge heterogeneity in Fc/2 dominates over F(ab´)2. In addition, a copy product of rituximab, and adalimumab were analyzed. Both mAbs contain additional alkaline C‐terminal lysine variants as confirmed by digest with carboxypeptidase B. The optimized CIEF methods for intact mAb and Fc/2 were tested for their potential as platform approaches for these mAbs. The CIEF method for Fc/2 was slightly adapted in this process. The pI values for major intact mAb variants were determined by adjacent pI markers resulting in 9.29 (rituximab) and 8.42 (adalimumab). In total, seven to eight charge variants could be distinguished for intact adalimumab and rituximab, respectively.
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Affiliation(s)
| | - Marcel W Vorage
- Department of Biosciences, University of Salzburg, Salzburg, Austria
| | - Hanno Stutz
- Department of Biosciences, University of Salzburg, Salzburg, Austria.,Christian Doppler Laboratory for Innovative Tools in the Characterization of Biosimilars, Salzburg, Austria
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6
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Zhang X, Chemmalil L, Ding J, Li Z. A novel approach enables imaged capillary isoelectric focusing analysis of PEGylated proteins. Electrophoresis 2020; 41:735-742. [DOI: 10.1002/elps.201900406] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 12/28/2019] [Accepted: 01/19/2020] [Indexed: 12/15/2022]
Affiliation(s)
- Xin Zhang
- Department of Biologics Process DevelopmentBristol‐Myers Squibb Devens MA
| | - Letha Chemmalil
- Department of Biologics Process DevelopmentBristol‐Myers Squibb Devens MA
| | - Julia Ding
- Department of Biologics Process DevelopmentBristol‐Myers Squibb Devens MA
| | - Zhengjian Li
- Department of Biologics Process DevelopmentBristol‐Myers Squibb Devens MA
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Duša F, Moravcová D, Šlais K. Low-molecular-mass nitrophenol-based compounds suitable for the effective tracking of pH gradient in isoelectric focusing. Anal Chim Acta 2019; 1076:144-153. [DOI: 10.1016/j.aca.2019.05.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 05/03/2019] [Accepted: 05/05/2019] [Indexed: 11/29/2022]
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8
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Ouyang Y, Han X, Xia Q, Chen J, Velagapudi S, Xia K, Zhang Z, Linhardt RJ. Negative-Ion Mode Capillary Isoelectric Focusing Mass Spectrometry for Charge-Based Separation of Acidic Oligosaccharides. Anal Chem 2018; 91:846-853. [DOI: 10.1021/acs.analchem.8b03500] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Yilan Ouyang
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases and College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu 215021, China
- Departments of Chemistry and Chemical Biology, Biology, Chemical and Biological Engineering, and Biomedical Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, New York 12180, United States
| | - Xiaorui Han
- Departments of Chemistry and Chemical Biology, Biology, Chemical and Biological Engineering, and Biomedical Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, New York 12180, United States
| | - Qiangwei Xia
- CMP Scientific Corporation, 760 Parkside Avenue, STE 211, Brooklyn, New York 11226, United States
| | - Jianle Chen
- Departments of Chemistry and Chemical Biology, Biology, Chemical and Biological Engineering, and Biomedical Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, New York 12180, United States
| | - Sheila Velagapudi
- Departments of Chemistry and Chemical Biology, Biology, Chemical and Biological Engineering, and Biomedical Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, New York 12180, United States
| | - Ke Xia
- Departments of Chemistry and Chemical Biology, Biology, Chemical and Biological Engineering, and Biomedical Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, New York 12180, United States
| | - Zhenqing Zhang
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases and College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu 215021, China
| | - Robert J. Linhardt
- Departments of Chemistry and Chemical Biology, Biology, Chemical and Biological Engineering, and Biomedical Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, New York 12180, United States
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9
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Kahle J, Wätzig H. Determination of protein charge variants with (imaged) capillary isoelectric focusing and capillary zone electrophoresis. Electrophoresis 2018; 39:2492-2511. [DOI: 10.1002/elps.201800079] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 04/03/2018] [Accepted: 04/17/2018] [Indexed: 12/20/2022]
Affiliation(s)
- Julia Kahle
- Technische Universität Braunschweig; Institute of Medicinal and Pharmaceutical Chemistry; Braunschweig Germany
| | - Hermann Wätzig
- Technische Universität Braunschweig; Institute of Medicinal and Pharmaceutical Chemistry; Braunschweig Germany
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10
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Turner A, Schiel JE. Qualification of NISTmAb charge heterogeneity control assays. Anal Bioanal Chem 2018; 410:2079-2093. [PMID: 29423598 PMCID: PMC5830499 DOI: 10.1007/s00216-017-0816-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Revised: 11/22/2017] [Accepted: 12/07/2017] [Indexed: 01/21/2023]
Abstract
The NISTmAb is a monoclonal antibody Reference Material from the National Institute of Standards and Technology; it is a class-representative IgG1κ intended serve as a pre-competitive platform for harmonization and technology development in the biopharmaceutical industry. The publication series of which this paper is a part describes NIST's overall control strategy to ensure NISTmAb quality and availability over its lifecycle. In this paper, the development and qualification of methods for monitoring NISTmAb charge heterogeneity are described. Capillary zone electrophoresis (CZE) and capillary isoelectric focusing (CIEF) assays were optimized and evaluated as candidate assays for NISTmAb quality control. CIEF was found to be suitable as a structural characterization assay yielding information on the apparent pI of the NISTmAb. CZE was found to be better suited for routine monitoring of NISTmAb charge heterogeneity and was qualified for this purpose. This paper is intended to provide relevant details of NIST's charge heterogeneity control strategy to facilitate implementation of the NISTmAb as a test molecule in the end user's laboratory. Graphical Abstract Representative capillary zone electropherogram of the NIST monoclonal antibody (NISTmAb). The NISTmAb is a publicly available research tool intended to facilitate advancement of biopharmaceutical analytics.
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Affiliation(s)
- Abigail Turner
- National Institute of Standards and Technology, Institute for Bioscience and Biotechnology Research, 9600 Gudelsky Dr, Rockville, MD, 20850, USA
- Medimmune, LLC, 55 Watkins Mill Rd, Gaithersburg, MD, 20878, USA
| | - John E Schiel
- National Institute of Standards and Technology, Institute for Bioscience and Biotechnology Research, 9600 Gudelsky Dr, Rockville, MD, 20850, USA.
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11
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Dai J, Lamp J, Xia Q, Zhang Y. Capillary Isoelectric Focusing-Mass Spectrometry Method for the Separation and Online Characterization of Intact Monoclonal Antibody Charge Variants. Anal Chem 2018; 90:2246-2254. [DOI: 10.1021/acs.analchem.7b04608] [Citation(s) in RCA: 73] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Jun Dai
- Bristol-Myers Squibb Research and Development, P.O.
Box 4000, Princeton, New Jersey 08543, United States
| | - Jared Lamp
- CMP Scientific, Corporation, 760 Parkside Avenue, Suite 211, Brooklyn, New York 11226, United States
| | - Qiangwei Xia
- CMP Scientific, Corporation, 760 Parkside Avenue, Suite 211, Brooklyn, New York 11226, United States
| | - Yingru Zhang
- Bristol-Myers Squibb Research and Development, P.O.
Box 4000, Princeton, New Jersey 08543, United States
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12
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Wang Z, Ivory C, Minerick AR. Surface isoelectric focusing (sIEF) with carrier ampholyte pH gradient. Electrophoresis 2017; 38:2565-2575. [PMID: 28722147 DOI: 10.1002/elps.201600565] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Revised: 06/16/2017] [Accepted: 07/12/2017] [Indexed: 11/08/2022]
Abstract
Isoelectric focusing (IEF) is a powerful tool for amphoteric protein separations because of high sensitivity, bio-compatibility, and reduced complexity compared to chromatography or mechanical separation techniques. IEF miniaturization is attractive because it enables rapid analysis, easier adaptation to point of care applications, and smaller sample demands. However, existing small-scale IEF tools have not yet been able to analyze single protein spots from array libraries, which are ubiquitous in many pharmaceutical discovery and screening protocols. Thus, we introduce an in situ, novel, miniaturized protein analysis approach that we have termed surface isoelectric focusing (sIEF). Low volume printed sIEF gels can be run at length scales of ∼300 μm, utilize ∼0.9 ng of protein with voltages below 10 V. Further, the sIEF device platform is so simple that it can be integrated with protein library arrays to reduce cost; devices demonstrate reusability above 50 uses. An acrylamide monomer solution containing broad-range carrier ampholytes was microprinted with a Nano eNablerTM between micropatterned gold electrodes spaced 300 μm apart on a glass slide. The acrylamide gel was polymerized in situ followed by protein loading via printed diffusional exchange. A pH gradient formed via carrier ampholyte stacking when electrodes were energized; the gradient was verified using ratiometric pH-sensitive FITC/TRITC dyes. Green fluorescent protein (GFP) and R-phycoerythrin (R-PE) were utilized both as pI markers and to test sIEF performance as a function of electric field strength and ampholyte concentration. Factors hampering sIEF included cathodic drift and pH gradient compression, but were reduced by co-printing non-ionic Synperonic® F-108 surfactant to reduce protein-gel interactions. sIEF gels achieved protein separations in <10 min yielding bands < 50 μm wide with peak capacities of ∼8 and minimum pI differences from 0.12 to 0.14. This new sIEF technique demonstrated comparable focusing at ∼100 times smaller dimensions than any previous IEF. Further, sample volumes required were reduced four orders of magnitude from 20 μL for slab gel IEF to 0.002 μL for sIEF. In summary, sIEF advantages include smaller volumes, reduced power consumption, and microchip surface accessibility to focused bands along with equivalent separation resolutions to prior IEF tools. These attributes position this new technology for rapid, in situ protein library analysis in clinical and pharmaceutical settings.
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Affiliation(s)
- Zhichao Wang
- Department of Chemical Engineering, Michigan Technological University, Houghton, MI, USA
| | - Cornelius Ivory
- Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA, USA
| | - Adrienne R Minerick
- Department of Chemical Engineering, Michigan Technological University, Houghton, MI, USA
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13
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Pergande MR, Cologna SM. Isoelectric Point Separations of Peptides and Proteins. Proteomes 2017; 5:proteomes5010004. [PMID: 28248255 PMCID: PMC5372225 DOI: 10.3390/proteomes5010004] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2016] [Revised: 01/03/2017] [Accepted: 01/08/2017] [Indexed: 12/20/2022] Open
Abstract
The separation of ampholytic components according to isoelectric point has played an important role in isolating, reducing complexity and improving peptide and protein detection. This brief review outlines the basics of isoelectric focusing, including a summary of the historical achievements and considerations in experimental design. Derivative methodologies of isoelectric focusing are also discussed including common detection methods used. Applications in a variety of fields using isoelectric point based separations are provided as well as an outlook on the field for future studies.
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Affiliation(s)
- Melissa R Pergande
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL 60607, USA.
| | - Stephanie M Cologna
- Department of Chemistry, University of Illinois at Chicago, Chicago, IL 60607, USA.
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14
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Brown S, Norris G. Improved consistency in 2D gel electrophoresis: Sheep plasma as a test case. Electrophoresis 2016; 38:906-913. [PMID: 27925263 DOI: 10.1002/elps.201600433] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Revised: 11/29/2016] [Accepted: 12/01/2016] [Indexed: 11/09/2022]
Abstract
Two-dimensional (2D) gel electrophoresis is a well-proven proteomic technique; however, sample-specific optimisation can often be necessary in order to get consistent quantitation. In particular, plasma samples are often smeared on 2D gels making spot matching difficult. A variety of different sample preparation and 2D methods were tested by using sheep plasma, and it was found that lowering sample pH prior to precipitation, using a long voltage gradient for isoelectric focusing and the inclusion of carrier ampholytes in the electrode wicks, improved both the quality and consistency of spot resolution. Analysis of the internal standards from two different DIGE experiments, one with conventional methodology and one with the improved method, showed that along with substantially improving the number of spots resolved, the average CV (coefficient of variation) of matched standards was lower with the new method. 428 matched spots were found using the improved method compared to 208 matched spots using conventional methodology. For the 174 spots that were matched between the two DIGE experiments, the average CV's of spot volumes were also significantly lower, at 0.20 for the new method compared to 0.24 for the conventional method (p < 0.001).
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Affiliation(s)
- Stuart Brown
- Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - Gillian Norris
- Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand
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15
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Takácsi-Nagy A, Kilár F, Thormann W. Modeling of formation and prevention of a pure water zone in capillary isoelectric focusing with narrow pH range carrier ampholytes. Electrophoresis 2016; 38:677-688. [PMID: 27699824 DOI: 10.1002/elps.201600314] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 09/01/2016] [Accepted: 09/02/2016] [Indexed: 11/07/2022]
Abstract
This paper comprises a continuation of computer simulation studies dealing with carrier ampholyte based CIEF in presence of narrow pH gradients. With this technique, amphoteric sample components with pI values outside the pH gradient are migrating isotachophoretically toward the cathode or anode whereas components with pI values within the gradient become focused. In order to understand the processes occurring in presence of the electric field, the behavior of both carrier ampholytes and amphoteric sample components is investigated by computer modeling. Characteristics of two pH unit gradients with end components having pI values at or around 7.00 and conditions that lead to the formation of a water zone at neutrality were investigated. Data obtained reveal that a zone of water is formed in focusing with carrier ampholytes when the applied pH range does not cover the neutral region, ends at pH 7.00 or begins at pH 7.00. The presence of additional amphoteric components that cover the neutrality region prevent water zone formation under current flow. This situation is met in experiments with narrow pH gradients that end or begin around neutrality. Simulation data reveal that no water zone evolves when atmospheric carbon dioxide dissolved in the catholyte causes the migration of carbonic acid (in the form of carbonate and/or hydrogen carbonate ions) from the catholyte through the focusing structure. An electrolyte change in the electrode solution does not have an impact on the focusing part but does change the isotachophoretic pattern migrating behind the leading ion.
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Affiliation(s)
- Anna Takácsi-Nagy
- Institute of Bioanalysis and Szentágothai Research Center, University of Pécs, Pécs, Hungary
| | - Ferenc Kilár
- Institute of Bioanalysis and Szentágothai Research Center, University of Pécs, Pécs, Hungary
| | - Wolfgang Thormann
- Clinical Pharmacology Laboratory, Institute for Infectious Diseases, University of Bern, Bern, Switzerland
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Mokaddem M, d'Orlyé F, Varenne A. Online Capillary IsoElectric Focusing-ElectroSpray Ionization Mass Spectrometry (CIEF-ESI MS) in Glycerol-Water Media for the Separation and Characterization of Hydrophilic and Hydrophobic Proteins. Methods Mol Biol 2016; 1466:57-66. [PMID: 27473481 DOI: 10.1007/978-1-4939-4014-1_5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Capillary isoelectric focusing (CIEF) is a high-resolution technique for the separation of ampholytes, such as proteins, according to their isoelectric point. CIEF coupled online with MS is regarded as a promising alternative to 2-D PAGE for fast proteome analysis with high-resolving capabilities and enhanced structural information without the drawbacks of conventional slab-gel electrophoresis. However, online coupling has been rarely described, as it presents some difficulties. A new methodology for the online coupling of CIEF with electrospray ionization mass spectrometry (ESI-MS) has been developed in glycerol-water media. This new integrated methodology provides a mean for the characterization of a large number of hydrophilic and hydrophobic proteins.
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Affiliation(s)
- Meriem Mokaddem
- Chimie ParisTech, PSL Research University Unité de Technologies Chimiques et Biologiques pour la Santé, Paris, 75005, France
- INSERM, Unité de Technologies Chimiques et Biologiques pour la Santé (n° 1022), Paris, 75005, France
- CNRS, Unité de Technologies Chimiques et Biologiques pour la santé UMR 8258, Paris, 75005, France
- Université Paris Descartes, Sorbonne Paris Cité, Unité de Technologies Chimiques et Biologiques pour la Santé, Paris, 75005, France
| | - Fanny d'Orlyé
- Chimie ParisTech, PSL Research University Unité de Technologies Chimiques et Biologiques pour la Santé, Paris, 75005, France
- INSERM, Unité de Technologies Chimiques et Biologiques pour la Santé (n° 1022), Paris, 75005, France
- CNRS, Unité de Technologies Chimiques et Biologiques pour la santé UMR 8258, Paris, 75005, France
- Université Paris Descartes, Sorbonne Paris Cité, Unité de Technologies Chimiques et Biologiques pour la Santé, Paris, 75005, France
| | - Anne Varenne
- Chimie ParisTech, PSL Research University Unité de Technologies Chimiques et Biologiques pour la Santé, Paris, 75005, France.
- INSERM, Unité de Technologies Chimiques et Biologiques pour la Santé (n° 1022), Paris, 75005, France.
- CNRS, Unité de Technologies Chimiques et Biologiques pour la santé UMR 8258, Paris, 75005, France.
- Université Paris Descartes, Sorbonne Paris Cité, Unité de Technologies Chimiques et Biologiques pour la Santé, Paris, 75005, France.
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Moritz B, Schnaible V, Kiessig S, Heyne A, Wild M, Finkler C, Christians S, Mueller K, Zhang L, Furuya K, Hassel M, Hamm M, Rustandi R, He Y, Solano OS, Whitmore C, Park SA, Hansen D, Santos M, Lies M. Evaluation of capillary zone electrophoresis for charge heterogeneity testing of monoclonal antibodies. J Chromatogr B Analyt Technol Biomed Life Sci 2015; 983-984:101-10. [DOI: 10.1016/j.jchromb.2014.12.024] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 12/19/2014] [Accepted: 12/22/2014] [Indexed: 01/30/2023]
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Kristl T, Stutz H. Comparison of different mobilization strategies for capillary isoelectric focusing of ovalbumin variants†. J Sep Sci 2014; 38:148-56. [DOI: 10.1002/jssc.201400890] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Revised: 10/20/2014] [Accepted: 10/20/2014] [Indexed: 11/08/2022]
Affiliation(s)
- Theresa Kristl
- Division of Chemistry and Bioanalytics; Department of Molecular Biology; University of Salzburg; Salzburg Austria
| | - Hanno Stutz
- Division of Chemistry and Bioanalytics; Department of Molecular Biology; University of Salzburg; Salzburg Austria
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Avoiding acidic region streaking in two-dimensional gel electrophoresis: Case study with two bacterial whole cell protein extracts. J Biosci 2014; 39:631-42. [DOI: 10.1007/s12038-014-9453-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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Zhao Y, Pereira F, deMello AJ, Morgan H, Niu X. Droplet-based in situ compartmentalization of chemically separated components after isoelectric focusing in a Slipchip. LAB ON A CHIP 2014; 14:555-561. [PMID: 24292781 DOI: 10.1039/c3lc51067k] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Isoelectric focusing (IEF) is a powerful and widely used technique for protein separation and purification. There are many embodiments of microscale IEF that use capillary or microfluidic chips for the analysis of small sample volumes. Nevertheless, collecting the separated sample volumes without causing remixing remains a challenge. Herein, we describe a microfluidic Slipchip device that is able to efficiently compartmentalize focused analyte bands in situ into microdroplets. The device contains a microfluidic "zig-zag" separation channel that is composed of a sequence of wells formed in the two halves of the Slipchip. The analytes are focused in the channel and then compartmentalised into droplets by slipping the chip. Importantly, sample droplets can be analysed on chip or collected for subsequent analysis using electrophoresis or mass spectrometry for example. To demonstrate this approach, we perform IEF separation using standard markers and protein samples, with on-chip post-processing. Compared to alternative approaches for sample collection, the method avoids remixing, is scalable and is easily hyphenated with the other analytical methods.
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Affiliation(s)
- Yan Zhao
- Faculty of Physical Sciences and Engineering, and Institute for Life Sciences, University of Southampton, Highfield, Southampton, SO17 1BJ, UK.
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The Monkey King: a personal view of the long journey towards a proteomic Nirvana. J Proteomics 2013; 107:39-49. [PMID: 24316443 DOI: 10.1016/j.jprot.2013.11.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Revised: 11/27/2013] [Accepted: 11/29/2013] [Indexed: 11/22/2022]
Abstract
UNLABELLED The review covers about fifty years of progress in "proteome" analysis, starting from primitive two-dimensional (2D) map attempts in the early sixties of last century. The polar star in 2D mapping arose in 1975 with the classic paper by O'Farrell in J Biol. Chem. It became the compass for all proteome navigators. Perfection came, though, only with the introduction of immobilized pH gradients, which fixed the polypeptide spots in the 2D plane. Great impetus in proteome analysis came with the introduction of informatic tools and creating databases, among which Swiss Prot remains the site of excellence. Towards the end of the nineties, 2D chromatography, epitomized by coupling strong cation exchangers with C18 resins, began to be a serious challenge to electrophoretic 2D mapping, although up to the present both techniques are still much in vogue and appear to give complementary results. Yet the migration of "proteomics" into the third millennium was made possible only by mass spectrometry (MS), which today represents the standard analytical tool in any lab dealing with proteomic analysis. Another major improvement has been the introduction of combinatorial peptide ligand libraries (CPLL), which, when properly used, enhance the visibility of low-abundance species by 3 to 4 orders of magnitude. Coupling MS to CPLLs permits the exploration of at least 8 orders of magnitude in dynamic range on any proteome. BIOLOGICAL SIGNIFICANCE The present review is a personal recollection highlighting the developments that led to present-day proteomics on a long march that lasted about 50years. It is meant to give to young scientists an overview on how science grows, which ones are the quantum jumps in science and which research is of particular significance in general and in the field of proteomics in particular. It also gives some real-life episodes of greater-than-life figures. As such, it can be viewed as a tutorial to stimulate the young generation to be creative (and use their imagination too!).This article is part of a Special Issue entitled: 20years of Proteomics in memory of Viatliano Pallini. Guest Editors: Luca Bini, Juan J. Calvete, Natacha Turck, Denis Hochstrasser and Jean-Charles Sanchez.
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The potential of electrophoretic sample pretreatment techniques and new instrumentation for bioanalysis, with a focus on peptidomics and metabolomics. Bioanalysis 2013; 5:2785-801. [DOI: 10.4155/bio.13.254] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
This Review highlights the potential of new electromigration-based sample pretreatment techniques for bioanalysis. Sample pretreatment is a challenging part of the analytical workflow, especially in the fields of peptidomics and metabolomics, where the analytes are very diverse, both in physicochemical properties and in endogenous concentration. Electromigration-based techniques have several strengths, such as fast selective analyte concentration and that complementary information on the content of a sample can be obtained when compared with more conventional (chromatography-based) techniques. In the past decade, various new electromigration-based sample pretreatment techniques have been developed, and importantly, new instrumental setups. In this Review, we provide an introduction on electromigration and its strengths. Then, selected examples of electromigration-based sample pretreatment techniques and instrumentation are discussed, namely free-flow electrophoresis, isoelectric focusing, isotachophoresis, electrodialysis, electromembrane extraction and electroextraction. Finally, the promising perspectives of electromigration-based sample pretreatment techniques are outlined.
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Wöhlbrand L, Trautwein K, Rabus R. Proteomic tools for environmental microbiology-A roadmap from sample preparation to protein identification and quantification. Proteomics 2013; 13:2700-30. [DOI: 10.1002/pmic.201300175] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 06/07/2013] [Accepted: 06/28/2013] [Indexed: 02/03/2023]
Affiliation(s)
- Lars Wöhlbrand
- Institute for Chemistry and Biology of the Marine Environment (ICBM); Carl von Ossietzky University Oldenburg; Oldenburg Germany
| | - Kathleen Trautwein
- Institute for Chemistry and Biology of the Marine Environment (ICBM); Carl von Ossietzky University Oldenburg; Oldenburg Germany
| | - Ralf Rabus
- Institute for Chemistry and Biology of the Marine Environment (ICBM); Carl von Ossietzky University Oldenburg; Oldenburg Germany
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24
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Righetti PG. Bioanalysis: Heri, hodie, cras. Electrophoresis 2013; 34:1442-51. [DOI: 10.1002/elps.201300001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Accepted: 01/09/2013] [Indexed: 12/11/2022]
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Millioni R, Franchin C, Tessari P, Polati R, Cecconi D, Arrigoni G. Pros and cons of peptide isolectric focusing in shotgun proteomics. J Chromatogr A 2013; 1293:1-9. [PMID: 23639126 DOI: 10.1016/j.chroma.2013.03.073] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2012] [Revised: 03/27/2013] [Accepted: 03/28/2013] [Indexed: 02/03/2023]
Abstract
In shotgun proteomics, protein mixtures are proteolytically digested before tandem mass spectrometry (MS/MS) analysis. Biological samples are generally characterized by a very high complexity, therefore a step of peptides fractionation before the MS analysis is essential. This passage reduces the sample complexity and increases its compatibility with the sampling performance of the instrument. Among all the existing approaches for peptide fractionation, isoelectric focusing has several peculiarities that are theoretically known but practically rarely exploited by the proteomics community. The main aim of this review is to draw the readers' attention to these unique qualities, which are not accessible with other common approaches, and that represent important tools to increase confidence in the identification of proteins and some post-translational modifications. The general characteristics of different methods to perform peptide isoelectric focusing with natural and artificial pH gradients, the existing instrumentation, and the informatics tools available for isoelectric point calculation are also critically described. Finally, we give some general conclusions on this strategy, underlying its principal limitations.
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Affiliation(s)
- Renato Millioni
- Department of Medicine, University of Padova, Via Giustiniani 2, 35121 Padova, Italy; Proteomics Center of Padova University, VIMM and Padova University Hospital, Via G. Orus 2/B, 35129 Padova, Italy.
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26
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Righetti PG, Sebastiano R, Citterio A. Capillary electrophoresis and isoelectric focusing in peptide and protein analysis. Proteomics 2012. [DOI: 10.1002/pmic.201200378] [Citation(s) in RCA: 134] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
| | - Roberto Sebastiano
- Department of Chemistry, Materials and Chemical Engineering “Giulio Natta”; Politecnico di Milano; Milano; Italy
| | - Attilio Citterio
- Department of Chemistry, Materials and Chemical Engineering “Giulio Natta”; Politecnico di Milano; Milano; Italy
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Šolínová V, Poitevin M, Koval D, Busnel JM, Peltre G, Kašička V. Capillary electrophoresis in classical and carrier ampholytes-based background electrolytes applied to separation and characterization of gonadotropin-releasing hormones. J Chromatogr A 2012; 1267:231-8. [DOI: 10.1016/j.chroma.2012.07.059] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Revised: 07/16/2012] [Accepted: 07/19/2012] [Indexed: 10/28/2022]
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Páger C, Vargová A, Takácsi-Nagy A, Dörnyei Á, Kilár F. Effect of electrolyte pH on CIEF with narrow pH range ampholytes. Electrophoresis 2012; 33:3269-75. [DOI: 10.1002/elps.201200175] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2012] [Revised: 07/05/2012] [Accepted: 07/23/2012] [Indexed: 01/19/2023]
Affiliation(s)
- Csilla Páger
- Institute of Bioanalysis; Faculty of Medicine; University of Pécs; Pécs; Hungary
| | - Andrea Vargová
- Department of Analytical and Environmental Chemistry; Faculty of Sciences; University of Pécs; Pécs; Hungary
| | - Anna Takácsi-Nagy
- Institute of Bioanalysis; Faculty of Medicine; University of Pécs; Pécs; Hungary
| | - Ágnes Dörnyei
- Institute of Bioanalysis; Faculty of Medicine; University of Pécs; Pécs; Hungary
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Koshel BM, Wirth MJ. Trajectory of isoelectric focusing from gels to capillaries to immobilized gradients in capillaries. Proteomics 2012; 12:2918-26. [PMID: 22930445 PMCID: PMC3799802 DOI: 10.1002/pmic.201200213] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Revised: 08/15/2012] [Accepted: 08/20/2012] [Indexed: 12/29/2022]
Abstract
This review presents the need for replacing gels in 2D separations for proteomics, where speed, high-throughput, and the ability to characterize trace level proteins or small samples are the current desires. The theme of the review is isoelectric focusing, which is a valuable tool because it pre-concentrates proteins in addition to separating with high peak capacity. The review traces the technological progress from gel IEF to CIEF to packed capillaries with immobilized gradients for CIEF. Multiple capillary techniques are progressing toward meeting the current desires, providing extremely high sensitivity with regard to concentration and to small samples, integrated automation, and high peak capacity from multiple dimensions of separation. Capillaries with immobilized pH gradients for CIEF are emerging, which will alleviate interference from ampholytes and improve reproducibility in separation times when this valuable technique can be used as one of the dimensions.
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Affiliation(s)
- Brooke M. Koshel
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907
| | - Mary J. Wirth
- Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, IN 47907
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Abstract
A dearth of protein isoform-based clinical diagnostics currently hinders advances in personalized medicine. A well-organized protein biomarker validation process that includes facile measurement of protein isoforms would accelerate development of effective protein-based diagnostics. Toward scalable protein isoform analysis, we introduce a microfluidic "single-channel, multistage" immunoblotting strategy. The multistep assay performs all immunoblotting steps: separation, immobilization of resolved proteins, antibody probing of immobilized proteins, and all interim wash steps. Programmable, low-dispersion electrophoretic transport obviates the need for pumps and valves. A three-dimensional bulk photoreactive hydrogel eliminates manual blotting. In addition to simplified operation and interfacing, directed electrophoretic transport through our 3D nanoporous reactive hydrogel yields superior performance over the state-of-the-art in enhanced capture efficiency (on par with membrane electroblotting) and sparing consumption of reagents (ca. 1 ng antibody), as supported by empirical and by scaling analyses. We apply our fully integrated microfluidic assay to protein measurements of endogenous prostate specific antigen isoforms in (i) minimally processed human prostate cancer cell lysate (1.1 pg limit of detection) and (ii) crude sera from metastatic prostate cancer patients. The single-instrument functionality establishes a scalable microfluidic framework for high-throughput targeted proteomics, as is relevant to personalized medicine through robust protein biomarker verification, systematic characterization of new antibody probes for functional proteomics, and, more broadly, to characterization of human biospecimen repositories.
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Membrane-assisted capillary isoelectric focusing coupling with matrix-assisted laser desorption/ionization-Fourier transform mass spectrometry for neuropeptide analysis. J Chromatogr A 2011; 1218:5336-43. [PMID: 21696746 DOI: 10.1016/j.chroma.2011.05.072] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Revised: 05/13/2011] [Accepted: 05/18/2011] [Indexed: 12/30/2022]
Abstract
Herein we report a highly efficient and reliable membrane-assisted capillary isoelectric focusing (MA-CIEF) system being coupled with MALDI-FTMS for the analysis of complex neuropeptide mixtures. The new interface consists of two membrane-coated joints made near each end of the capillary for applying high voltage, while the capillary ends were placed in the two reservoirs which were filled with anolyte (acid) and catholyte (base) to provide pH difference. Optimizations of CIEF conditions and comparison with conventional CIEF were carried out by using bovine serum albumin (BSA) tryptic peptides. It was shown that the MA-CIEF could provide more efficient, reliable and faster separation with improved sequence coverage when coupled to MALDI-FTMS. Analyses of orcokinin family neuropeptides from crabs Cancer borealis and Callinectes sapidus brain extracts have been conducted using the established MA-CIEF/MALDI-FTMS platform. Increased number of neuropeptides was observed with significantly enhanced MS signal in comparison with direct analysis by MALDI-FTMS. The results highlighted the potential of MA-CIEF as an efficient fractionation tool for coupling to MALDI MS for neuropeptide analysis.
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32
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Righetti PG, Candiano G. Recent advances in electrophoretic techniques for the characterization of protein biomolecules: a poker of aces. J Chromatogr A 2011; 1218:8727-37. [PMID: 21536293 DOI: 10.1016/j.chroma.2011.04.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2011] [Revised: 04/02/2011] [Accepted: 04/04/2011] [Indexed: 12/15/2022]
Abstract
The four classical modes of electrophoresis of protein molecules (sodium dodecyl sulphate electrophoresis, SDS-PAGE, isoelectric focusing, IEF, and immobilized pH gradients, IPGs, two-dimensional maps, 2D, and capillary electrophoresis, CE) are here reviewed, with special emphasis on recent innovations. Thus, in the case of SDS-PAGE, a novel method, consisting in focusing SDS-protein micelles against a gradient of cationic charges grafted onto a polyacrylamide gel is presented. In the case of IEF, the recent decoding of the structure, polydispersity, molecular mass distribution and buffering properties of the soluble carrier ampholyte buffers are here discussed. In regard to two dimensional mapping, recent instrumentation for performing 2D maps in horizontal, large gel slabs (up to 30 cm × 40 cm) and in a radial format for the SDS dimension is here evaluated. Finally, in the case of CE, three major applications are presented: a thorough study of capillary IEF and of all experimental variables, a method of importance in screening of rDNA products; the possibility of running proteins and peptide separations in very acidic, amphoteric, isoelectric buffers in absence of any capillary coating; finally, the possibility of producing a facile, user friendly, covalent coating of the wall silanols via bonding of quaternarized piperazines endowed with an iodinated tail. In acidic, volatile buffers, such protein/peptide runs can be directly interfaced with mass spectrometry instrumentation.
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Affiliation(s)
- Pier Giorgio Righetti
- Department of Chemistry, Materials and Chemical Engineering Giulio Natta, Politecnico di Milano, Via Mancinelli 7, 20131 Milano, Italy.
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Abstract
Mitochondria are highly heterogeneous organelles that likely have unique isoelectric points (pI), which are related to their surface compositions and could be exploited in their purification and isolation. Previous methods to determine pI of mitochondria report an average pI. This article is the first report of the determination of the isoelectric points of individual mitochondria by capillary isoelectric focusing (cIEF). In this method, mitochondria labeled with the mitochondrial-specific probe 10-N-nonyl acridine orange (NAO) are injected into a fused-silica capillary in a solution of carrier ampholytes at physiological pH and osmolarity, where they are focused then chemically mobilized and detected by laser-induced fluorescence (LIF). Fluorescein-derived pI markers are used as internal standards to assign a pI value to each individually detected mitochondrial event, and a mitochondrial pI distribution is determined. This method provides reproducible distributions of individual mitochondrial pI, accurate determination of the pI of individual mitochondria by the use of internal standards, and resolution of 0.03 pH units between individual mitochondria. This method could also be applied to investigate or design separations of organelle subtypes (e.g., subsarcolemmal and interfibrillar skeletal muscle mitochondria) and to determine the pIs of other biological or nonbiological particles.
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Affiliation(s)
- Gregory G. Wolken
- Department of Chemistry, University of Minnesota, Minneapolis, MN, USA 55455
| | - Vratislav Kostal
- Department of Chemistry, University of Minnesota, Minneapolis, MN, USA 55455
| | - Edgar A. Arriaga
- Department of Chemistry, University of Minnesota, Minneapolis, MN, USA 55455
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Kataoka M, Yokoyama H, Henares TG, Kawamura K, Yao T, Hisamoto H. Reagent-release capillary array-isoelectric focusing device as a rapid screening device for IEF condition optimization. LAB ON A CHIP 2010; 10:3341-3347. [PMID: 20714639 DOI: 10.1039/c0lc00019a] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
This report describes the fabrication and characterization of a simple and disposable capillary isoelectric focusing (cIEF) device containing a reagent-release capillary (RRC) array and poly(dimethylsiloxane) (PDMS) platform, which allows rapid (within 10 min) screening of cIEF conditions by introducing a sample solution into plural RRCs by capillary action followed by electric field application. To prepare the RRC, covalent immobilization of poly(dimethylacrylamide) (PDMA) was conducted to suppress electro-osmotic flow (EOF), followed by physical adsorption of the mixture of carrier ampholyte (CA), surfactant, labeling reagent (LR), and other additives to the PDMA surface to construct a two-layer structure inside a square glass capillary. When the sample solution containing proteins was introduced into the RRC, physically adsorbed CA, surfactant, and LR can be dissolved and released into the sample solution. Then, complexation of LR with proteins, mixing with CA and surfactant, and exposure of the PDMA surface spontaneously occurs for the IEF experiments. Here, three different RRCs that immobilize different CAs were prepared, and simultaneous cIEF experiments involving hemoglobin AFSC mixtures for choosing the best CA demonstrated the proof of concept.
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Affiliation(s)
- Masaki Kataoka
- Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai City, Osaka 599-8531, Japan
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Ramsay LM, Dickerson JA, Dada O, Dovichi NJ. Femtomolar concentration detection limit and zeptomole mass detection limit for protein separation by capillary isoelectric focusing and laser-induced fluorescence detection. Anal Chem 2010; 81:1741-6. [PMID: 19206532 DOI: 10.1021/ac8025948] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Fluorescence tends to produce the lowest detection limits for most forms of capillary electrophoresis. Two issues have discouraged its use in capillary isoelectric focusing. The first issue is fluorescent labeling of proteins. Most labeling reagents react with lysine residues and convert the cationic residue to a neutral or anionic product. At best, these reagents perturb the isoelectric point of the protein. At worse, they convert each protein into hundreds of different fluorescent products that confound analysis. The second issue is the large background signal generated by impurities within commercial ampholytes. This background signal is particularly strong when excited in the blue portion of the spectrum, which is required by many common fluorescent labeling reagents. This paper addresses these issues. For labeling, we employ Chromeo P540, which is a fluorogenic reagent that converts cationic lysine residues to cationic fluorescent products. The reaction products are excited in the green, which reduces the background signal generated by impurities present within the ampholytes. To further reduce the background signal, we photobleach ampholytes with high-power photodiodes. Photobleaching reduced the noise in the ampholyte blank by an order of magnitude. Isoelectric focusing performed with photobleached pH 3-10 ampholytes produced concentration detection limits of 270 +/- 25 fM and mass detection limits of 150 +/- 15 zmol for Chromeo P540 labeled beta-lactoglobulin. Concentration detection limits were 520 +/- 40 fM and mass detection limits were 310 +/- 30 zmol with pH 4-8 ampholytes. A homogenate was prepared from a Barrett's esophagus cell line and separated by capillary isoelectric focusing, reproducibly generating dozens of peaks. The sample taken for the separation was equal to the labeled protein homogenate from three cells.
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Affiliation(s)
- Lauren M Ramsay
- Department of Chemistry, University of Washington, Seattle, Washington 98195, USA
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37
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Zilberstein G, Bukshpan S, Righetti PG. Third generation of focusing: gel matrices with immobilized cation gradients. Electrophoresis 2010; 31:1747-53. [PMID: 20446287 DOI: 10.1002/elps.200900602] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A novel method is reviewed here for separation of polyanions, based not on conventional zone electrophoretic means, but on a "steady-state" process by which said polyanions are driven to stationary zones along the migration path against a gradient of positive charges affixed to the neutral polyacrylamide matrix. As the total negative surface charge of such polyanions matches the surrounding charge density of the matrix, they stop migrating and remain stationary, as typical of steady-state separation techniques. This technique has been successfully applied to SDS-protein micelles, DNAs, RNAs and heparins, with remarkable separations, often much superior than those obtained in conventional techniques. Additionally, by exploiting constant plateaus of charges, rather than gradients, it is possible to amplify the separation between species having closely spaced charge densities. This technique resembles a classical IEF process, with the proviso that the polyanions cannot be applied at any position along the gel matrix, but only at the point of low (or zero) charge density. The merits and limits of the technique are assessed.
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Bercovici M, Kaigala GV, Backhouse CJ, Santiago JG. Fluorescent Carrier Ampholytes Assay for Portable, Label-Free Detection of Chemical Toxins in Tap Water. Anal Chem 2010; 82:1858-66. [DOI: 10.1021/ac902526g] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- M. Bercovici
- Department of Aeronautics and Astronautics, Stanford University, Stanford, California 94305, Department of Mechanical Engineering, Stanford University, Stanford, California 94305, and Department of Electrical and Computer Engineering, University of Alberta, Edmonton Alberta T6G 2V4, Canada
| | - G. V. Kaigala
- Department of Aeronautics and Astronautics, Stanford University, Stanford, California 94305, Department of Mechanical Engineering, Stanford University, Stanford, California 94305, and Department of Electrical and Computer Engineering, University of Alberta, Edmonton Alberta T6G 2V4, Canada
| | - C. J. Backhouse
- Department of Aeronautics and Astronautics, Stanford University, Stanford, California 94305, Department of Mechanical Engineering, Stanford University, Stanford, California 94305, and Department of Electrical and Computer Engineering, University of Alberta, Edmonton Alberta T6G 2V4, Canada
| | - J. G. Santiago
- Department of Aeronautics and Astronautics, Stanford University, Stanford, California 94305, Department of Mechanical Engineering, Stanford University, Stanford, California 94305, and Department of Electrical and Computer Engineering, University of Alberta, Edmonton Alberta T6G 2V4, Canada
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Mokaddem M, Gareil P, Varenne A. Online CIEF-ESI-MS in glycerol-water media with a view to hydrophobic protein applications. Electrophoresis 2010; 30:4040-8. [PMID: 19960468 DOI: 10.1002/elps.200900091] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A new online coupling of CIEF with ESI-MS has been developed in glycerol-water media. This improved protocol provides: (i) the electric continuity during the whole analysis by a discontinuous filling of the capillary with 60:40 (cm/cm) catholyte/proteins-ampholyte mixture; (ii) the use of an anticonvective medium, i.e. 30:70 glycerol/water, v/v, compatible with MS detection and as an aid to hydrophobic protein solubilization and (iii) the use of unmodified bare fused-silica capillaries, as the glycerol/water medium strongly reduces EOF. Focusing was performed in positive polarity and cathodic mobilization was achieved by both voltage and pressure application. The setup was optimized with respect to analysis time, sensitivity and precision on pI determination. The optimized anolyte and catholyte were composed of 50 mM formic acid/1 mM glutamic acid (pH 2.35) and 100 mM NH(3)/1 mM lysine (pH 10.6), respectively. The effects of ampholyte concentration, focusing time and ESI parameters were presented for model proteins and discussed. This new integrated protocol should be an easy and effective additional tool in the field of proteome analysis, providing a means for the characterization of a large number of hydrophilic and hydrophobic proteins.
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Affiliation(s)
- Meriem Mokaddem
- Laboratoire de Physicochimie des Electrolytes, Colloïdes et Sciences Analytiques, UMR CNRS-UPMC, Ecole Nationale Supérieure de Chimie de Paris, 75231 Paris, France
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Friedman DB, Hoving S, Westermeier R. Chapter 30 Isoelectric Focusing and Two-Dimensional Gel Electrophoresis. Methods Enzymol 2009; 463:515-40. [DOI: 10.1016/s0076-6879(09)63030-5] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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Koval D, Busnel J, Hlaváček J, Jiráček J, Kašička V, Peltre G. Evaluation of carrier ampholyte‐based capillary electrophoresis for separation of peptides and peptide mimetics. Electrophoresis 2008; 29:3759-67. [DOI: 10.1002/elps.200800193] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Dušan Koval
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Jean‐Marc Busnel
- Laboratoire Environnement et Chimie and Analytique, Ecole Supérieure de Physique et Chimie Industrielles, Paris, France
- Laboratoire d'Electrochimie Physique et Analytique, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Jan Hlaváček
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Jiří Jiráček
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Václav Kašička
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Gabriel Peltre
- Laboratoire Environnement et Chimie and Analytique, Ecole Supérieure de Physique et Chimie Industrielles, Paris, France
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Recent developments in capillary isoelectric focusing. J Chromatogr A 2008; 1204:157-70. [DOI: 10.1016/j.chroma.2008.05.057] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2008] [Revised: 04/30/2008] [Accepted: 05/08/2008] [Indexed: 12/22/2022]
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Poitevin M, Hammad K, Ayed I, Righetti PG, Peltre G, Descroix S. Use of quasi-isoelectric buffers to limit protein adsorption in capillary zone electrophoresis. Electrophoresis 2008; 29:3164-7. [DOI: 10.1002/elps.200800100] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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