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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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3
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Wolfbeis OS. Fluorescent chameleon labels for bioconjugation and imaging of proteins, nucleic acids, biogenic amines and surface amino groups. a review. Methods Appl Fluoresc 2021; 9. [PMID: 34340216 DOI: 10.1088/2050-6120/ac1a0a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 08/02/2021] [Indexed: 12/14/2022]
Abstract
Chameleon labels (ChLs) possess the unique property of changing (visible) color and fluorescence on binding to amino groups of biomolecules. MostChLs react with primary aliphatic amino groups such as those in lysine or with amino groups artificially introduced into polynucleic acids or saccharides, but someothers also react with secondary amino groups. Under controlled circumstances, the reactions are fairly specific. The review is subdivided into the following sections: (1) An introduction and classification of fluorescent labels; (2) pyrylium labels that undergo shortwave color changes upon labelling, typically from blue to red; (3) polymethine type of labels (that also undergo shortwave color changes, typically from green to blue; (4) various other (less common) chromogenic and fluorogenic systems; (5) hemicyanine labels that undergolongwavecolor changes, typically from yellow to purple; (6) the application of ChLs to labeling of proteins and oligonucleotides; (7) applications to fluorometric assays and sensing; (8) applications to fluorescence imaging of biomolecules; (9) applications in studies on affinity interactions (receptor-ligand binding); (10) applications in surface and interface chemistry; and (11) applications in chromatography, electrophoresis and isotachophoresis of biomolecules.
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Affiliation(s)
- Otto S Wolfbeis
- University of Regensburg, Institute of Analytical Chemistry, Chemo- and Biosensors, 94040 Regensburg, Germany
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5
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Breadmore MC, Grochocki W, Kalsoom U, Alves MN, Phung SC, Rokh MT, Cabot JM, Ghiasvand A, Li F, Shallan AI, Keyon ASA, Alhusban AA, See HH, Wuethrich A, Dawod M, Quirino JP. Recent advances in enhancing the sensitivity of electrophoresis and electrochromatography in capillaries and microchips (2016-2018). Electrophoresis 2018; 40:17-39. [PMID: 30362581 DOI: 10.1002/elps.201800384] [Citation(s) in RCA: 96] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 10/15/2018] [Accepted: 10/16/2018] [Indexed: 12/22/2022]
Abstract
One of the most cited limitations of capillary and microchip electrophoresis is the poor sensitivity. This review continues to update this series of biannual reviews, first published in Electrophoresis in 2007, on developments in the field of online/in-line concentration methods in capillaries and microchips, covering the period July 2016-June 2018. It includes developments in the field of stacking, covering all methods from field-amplified sample stacking and large-volume sample stacking, through to isotachophoresis, dynamic pH junction, and sweeping. Attention is also given to online 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, Chemistry, School of Natural Science, University of Tasmania, Hobart, Tasmania, Australia
| | - Wojciech Grochocki
- Australian Centre for Research on Separation Science, Chemistry, School of Natural Science, University of Tasmania, Hobart, Tasmania, Australia.,Department of Biopharmaceutics and Pharmacodynamics, Medical University of Gdansk, Gdansk, Poland
| | - Umme Kalsoom
- Australian Centre for Research on Separation Science, Chemistry, School of Natural Science, University of Tasmania, Hobart, Tasmania, Australia.,ARC Centre of Excellence for Electromaterials Science (ACES), School of Natural Sciences, College of Science and Technology, University of Tasmania, Hobart, Australia
| | - Mónica N Alves
- Australian Centre for Research on Separation Science, Chemistry, School of Natural Science, University of Tasmania, Hobart, Tasmania, Australia
| | - Sui Ching Phung
- Australian Centre for Research on Separation Science, Chemistry, School of Natural Science, University of Tasmania, Hobart, Tasmania, Australia
| | | | - Joan M Cabot
- Australian Centre for Research on Separation Science, Chemistry, School of Natural Science, University of Tasmania, Hobart, Tasmania, Australia.,ARC Centre of Excellence for Electromaterials Science (ACES), School of Natural Sciences, College of Science and Technology, University of Tasmania, Hobart, Australia
| | - Alireza Ghiasvand
- Australian Centre for Research on Separation Science, Chemistry, School of Natural Science, University of Tasmania, Hobart, Tasmania, Australia.,Department of Chemistry, Lorestan University, Khoramabad, Iran
| | - Feng Li
- Australian Centre for Research on Separation Science, Chemistry, School of Natural Science, University of Tasmania, Hobart, Tasmania, Australia
| | - Aliaa I Shallan
- Future Industries Institute (FII), University of South Australia, Mawson Lakes, Australia.,Department of Pharmaceutical Analytical Chemistry, Faculty of Pharmacy, Helwan University, Cairo, Egypt
| | - Aemi S Abdul Keyon
- Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, Johor Bahru, Johor, Malaysia.,Centre for Sustainable Nanomaterials, Ibnu Sina Institute for Scientific and Industrial Research, Universiti Teknologi Malaysia, Johor Bahru, Johor, Malaysia
| | - Ala A Alhusban
- Department of Pharmacy, Faculty of Pharmacy, Al-Zaytoonah University of Jordan, Amman, Jordan
| | - Hong Heng See
- Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, Johor Bahru, Johor, Malaysia.,Centre for Sustainable Nanomaterials, Ibnu Sina Institute for Scientific and Industrial Research, Universiti Teknologi Malaysia, Johor Bahru, Johor, Malaysia
| | - Alain Wuethrich
- Centre for Personalized Nanomedicine, Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, QLD, Australia
| | - Mohamed Dawod
- Department of Chemistry, University of Michigan, Ann Arbor, MI, USA
| | - Joselito P Quirino
- Australian Centre for Research on Separation Science, Chemistry, School of Natural Science, University of Tasmania, Hobart, Tasmania, Australia
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