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Dhellemmes L, Leclercq L, Lichtenauer L, Höchsmann A, Leitner M, Ebner A, Martin M, Neusüß C, Cottet H. Dual Contributions of Analyte Adsorption and Electroosmotic Inhomogeneity to Separation Efficiency in Capillary Electrophoresis of Proteins. Anal Chem 2024; 96:11172-11180. [PMID: 38946102 DOI: 10.1021/acs.analchem.4c00274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Improving separation efficiency in capillary electrophoresis (CE) requires systematic study of the influence of the electric field (or solute linear velocity) on plate height for a better understanding of the critical parameters controlling peak broadening. Even for poly(diallyldimethylammonium chloride) (PDADMAC)/poly(sodium styrenesulfonate) (PSS) successive multiple ionic-polymer layer (SMIL) coatings, which lead to efficient and reproducible separations of proteins, plate height increases with migration velocity, limiting the use of high electric fields in CE. Solute adsorption onto the capillary wall was generally considered as the main source of peak dispersion, explaining this plate height increase. However, experiments done with Taylor dispersion analysis and CE in the same conditions indicate that other phenomena may come into play. Protein adsorption with slow kinetics and few adsorption sites was established as a source of peak broadening for specific proteins. Surface charge inhomogeneity was also identified as a contribution to plate height due to local electroosmotic fluctuations. A model was proposed and applied to partial PDADMAC/poly(ethylene oxide) capillary coatings as well as PDADMAC/PSS SMIL coatings. Atomic force microscopy with topography and recognition imaging enabled the determination of roughness and charge distribution of the PDADMAC/PSS SMIL surface.
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Affiliation(s)
- Laura Dhellemmes
- IBMM, University of Montpellier, CNRS, ENSCM, Montpellier 34095, France
| | - Laurent Leclercq
- IBMM, University of Montpellier, CNRS, ENSCM, Montpellier 34095, France
| | - Lisa Lichtenauer
- Institute of Biophysics, Johannes Kepler University Linz, Linz 4020, Austria
| | - Alisa Höchsmann
- Faculty of Chemistry, Aalen University, Aalen 73430, Germany
| | - Michael Leitner
- Institute of Biophysics, Johannes Kepler University Linz, Linz 4020, Austria
| | - Andreas Ebner
- Institute of Biophysics, Johannes Kepler University Linz, Linz 4020, Austria
| | - Michel Martin
- PMMH, CNRS, ESPCI Paris-PSL, Sorbonne Université, Université de Paris, Paris 75005, France
| | | | - Hervé Cottet
- IBMM, University of Montpellier, CNRS, ENSCM, Montpellier 34095, France
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Roca S, Dhellemmes L, Leclercq L, Cottet H. Polyelectrolyte Multilayers in Capillary Electrophoresis. Chempluschem 2022; 87:e202200028. [PMID: 35388990 DOI: 10.1002/cplu.202200028] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 03/19/2022] [Indexed: 02/21/2024]
Abstract
Capillary electrophoresis (CE) has been proven to be a performant analytical method to analyze both small and macro molecules. Indeed, it is capable of separating compounds of the same nature according to differences in their charge to size ratios, particularly proteins, monoclonal antibodies and peptides. However, one of the major obstacles to reach high separation efficiency remains the adsorption of solutes on the capillary wall. Among the different coating approaches used to control and minimize solute adsorption, polyelectrolyte multilayers can be applied to CE as a versatile approach. These coatings are made up of alternating layers of polycations and polyanions, and may be used in acidic, neutral or basic conditions depending on the solutes to be analyzed. This Review provides an overview of Successive Multiple Ionic-polymer Layer (SMIL) coatings used in CE, looking at how different parameters induce variations on the electro-osmotic flow (EOF), separation efficiency and coating stability, as well as their promising applications in the biopharmaceutical field.
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Affiliation(s)
- Sébastien Roca
- IBMM, University of Montpellier, CNRS, ENSCM, Montpellier, France
| | - Laura Dhellemmes
- IBMM, University of Montpellier, CNRS, ENSCM, Montpellier, France
| | - Laurent Leclercq
- IBMM, University of Montpellier, CNRS, ENSCM, Montpellier, France
| | - Hervé Cottet
- IBMM, University of Montpellier, CNRS, ENSCM, Montpellier, France
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Tohala L, Oukacine F, Ravelet C, Peyrin E. Sequence requirements of oligonucleotide chiral selectors for the capillary electrophoresis resolution of low-affinity DNA binders. Electrophoresis 2017; 38:1383-1390. [PMID: 28256731 DOI: 10.1002/elps.201600516] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 01/21/2017] [Accepted: 02/28/2017] [Indexed: 12/23/2022]
Abstract
We recently reported that a great variety of DNA oligonucleotides (ONs) used as chiral selectors in partial-filling capillary electrophoresis (CE) exhibited interesting enantioresolution properties toward low-affinity DNA binders. Herein, the sequence prerequisites of ONs for the CE enantioseparation process were studied. First, the chiral resolution properties of a series of homopolymeric sequences (Poly-dT) of different lengths (from 5 to 60-mer) were investigated. It was shown that the size increase-dependent random coil-like conformation of Poly-dT favorably acted on the apparent selectivity and resolution. The base-unpairing state constituted also an important factor in the chiral resolution ability of ONs as the switch from the single-stranded to double-stranded structure was responsible for a significant decrease in the analyte selectivity range. Finally, the chemical diversity enhanced the enantioresolution ability of single-stranded ONs. The present work could lay the foundation for the design of performant ON chiral selectors for the CE separation of weak DNA binder enantiomers.
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Affiliation(s)
- Luma Tohala
- DPM, UMR 5063, Université Grenoble Alpes, CNRS, Grenoble, France
| | - Farid Oukacine
- DPM, UMR 5063, Université Grenoble Alpes, CNRS, Grenoble, France
| | - Corinne Ravelet
- DPM, UMR 5063, Université Grenoble Alpes, CNRS, Grenoble, France
| | - Eric Peyrin
- DPM, UMR 5063, Université Grenoble Alpes, CNRS, Grenoble, France
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Loessberg-Zahl J, Janssen KGH, McCallum C, Gillespie D, Pennathur S. (Almost) Stationary Isotachophoretic Concentration Boundary in a Nanofluidic Channel Using Charge Inversion. Anal Chem 2016; 88:6145-50. [DOI: 10.1021/acs.analchem.6b01701] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Josh Loessberg-Zahl
- Department
of Mechanical Engineering, University of California, Santa Barbara, California 93106, United States
| | - Kjeld G. H. Janssen
- Department
of Mechanical Engineering, University of California, Santa Barbara, California 93106, United States
| | - Christopher McCallum
- Department
of Mechanical Engineering, University of California, Santa Barbara, California 93106, United States
| | - Dirk Gillespie
- Department
of Molecular Biophysics and Physiology, Rush University Medical Center, Chicago, Illinois 60612, United States
| | - Sumita Pennathur
- Department
of Mechanical Engineering, University of California, Santa Barbara, California 93106, United States
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Wells SS, De La Toba E, Harrison CR. Metal cation control of electroosmotic flow magnitude in phospholipid-coated capillaries. Electrophoresis 2016; 37:1303-9. [PMID: 26960035 DOI: 10.1002/elps.201600012] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Revised: 02/23/2016] [Accepted: 02/25/2016] [Indexed: 11/09/2022]
Abstract
CZE has become widespread for the separation and analysis of biomolecules such as proteins and peptides, due to factors such as, the speed of the separations, low sample volume, and high resolution associated with the technique. However, the separation of biomolecules by CZE does present a significant challenge due to the electrostatic attraction and adsorption of cationic, or cation containing, biomolecules to the capillary surface. To that end numerous methods have been developed to passivate, or protect the surface, in order to prevent the adsorption of analytes. Yet, in the process of protecting the capillary surface, the potential for further modification of the EOF, a factor crucial to effective analyte resolution, is greatly diminished. In seeking to overcome this limitation we have explored the potential of incorporating a range of metal cations into a phospholipid bilayer capillary coating. It has previously been established that the inclusion of calcium into the separation buffer with a phospholipid coating will reverse the EOF in the capillary. Here, we present our investigation of a broader range of metal cations included in the separation buffer (Ca(2+) , Mg(2+) , Co(2+) , Ni(2+) , Sr(2+) , Ba(2+) , and Ce(3+) ) revealing that the choice of metal cation can drastically influence the EOF, with observed values between -3.80 × 10(-4) and -5.74 × 10(-5) cm(2) /V·s.
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Affiliation(s)
- Shane S Wells
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, CA, USA
| | - Eduardo De La Toba
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, CA, USA
| | - Christopher R Harrison
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, CA, USA
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Wang Q, Zhang Y, Ding H, Wu J, Wang L, Zhou L, Pu Q. The use of ethylene glycol solution as the running buffer for highly efficient microchip-based electrophoresis in unmodified cyclic olefin copolymer microchips. J Chromatogr A 2011; 1218:9422-7. [PMID: 22099226 DOI: 10.1016/j.chroma.2011.10.078] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Revised: 10/25/2011] [Accepted: 10/27/2011] [Indexed: 11/18/2022]
Abstract
An ethylene glycol solution was used as the electrophoretic running buffer in unmodified cyclic olefin copolymer (COC) microchips to minimize the interactions between the analytes and the hydrophobic walls of the plastic microchannels, enhance the resolution of the analytes and eliminate the uncontrollable dispersion caused by uneven liquid levels and non-uniform surfaces of the separation channels. Five amino acids that were labeled with fluorescein isothiocyanate (FITC) were used as model analytes to examine the separation efficiency. The effects of ethylene glycol concentration, pH and sodium tetraborate concentration were systematically investigated. The five FITC-labeled amino acids were effectively resolved using a COC microchip with an effective length of 2.5 cm under optimum conditions, which included using a running buffer of 20 mmol/L sodium tetraborate in ethylene glycol:water (80:20, v/v), pH 6.7. A theoretical plate number of 4.8 × 10(5)/m was obtained for aspartic acid. The system exhibited good repeatability, and the relative standard deviations (n=5) of the peak areas and migration times were no more than 3.4% and 0.7%, respectively. Furthermore, the system was successfully applied to elucidate these five amino acids in human saliva.
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Affiliation(s)
- Qin Wang
- Key Laboratory of Nonferrous Metals Chemistry and Resources Utilization, Gansu Province, Sate Key Laboratory of Applied Organic Chemistry, Department of Chemistry, Lanzhou University, 222 Southern Tianshui Road, Lanzhou, Gansu 730000, China
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Nehmé R, Perrin C, Cottet H, Blanchin MD, Fabre H. Stability of capillaries coated with highly charged polyelectrolyte monolayers and multilayers under various analytical conditions—Application to protein analysis. J Chromatogr A 2011; 1218:3537-44. [DOI: 10.1016/j.chroma.2011.03.040] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Revised: 03/14/2011] [Accepted: 03/15/2011] [Indexed: 11/26/2022]
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Malá Z, Gebauer P, Boček P. Contemporary sample stacking in analytical electrophoresis. Electrophoresis 2010; 32:116-26. [DOI: 10.1002/elps.201000327] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2010] [Revised: 08/09/2010] [Accepted: 08/09/2010] [Indexed: 12/31/2022]
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Nehmé R, Perrin C, Guerlavais V, Fehrentz JA, Cottet H, Martinez J, Fabre H. Use of coated capillaries for the electrophoretic separation of stereoisomers of a growth hormone secretagogue. Electrophoresis 2009; 30:3772-9. [DOI: 10.1002/elps.200900093] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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On-line sample stacking of peptides in capillary electrophoresis for the study of prebiotic reactions between alpha,alpha-dialkylated amino acids and amino acid N-carboxyanhydrides. J Chromatogr A 2009; 1216:5748-54. [PMID: 19539298 DOI: 10.1016/j.chroma.2009.06.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2009] [Revised: 05/20/2009] [Accepted: 06/03/2009] [Indexed: 11/23/2022]
Abstract
The reaction between alpha,alpha-dialkylated amino acids and amino acid N-carboxyanhydrides is slow leading to low concentrations of products (peptides). The detection by capillary electrophoresis of the analytes contained in such samples is therefore a challenging issue. In this work, on-line sample pre-concentration methods based on field-amplified sample stacking have been implemented and compared. Because of the high ionic strength present in the sample matrix, samples were diluted with an organic solvent prior to analysis to decrease the sample conductivity. Different modes of sample injection (field amplified sample injection (FASI), hydrodynamic normal sample stacking (NSS) or large volume sample stacking (LVSS)) were compared. Pre-concentration factors of 20 for FASI, about 30-40 for NSS and 60 for LVSS were obtained for the analysis of (l,l) dipeptide of valine in a large excess of isovaline and 0.2M of ionic strength. For LVSS application and resolution optimisation, a new non-covalent coating based on the partial modification of the capillary surface was used to tune the electroosmotic flow magnitude and to pump the sample matrix out of the capillary. This on-line sample pre-concentration step allowed confirming that oligopeptides including alpha,alpha-dialkylated amino acids are formed during the reaction between alpha,alpha-dialkylated amino acids and N-carboxyanhydride amino acids.
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