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Rahmanian N, Bozorgmehr M, Torabi M, Akbari A, Zarnani AH. Cell separation: Potentials and pitfalls. Prep Biochem Biotechnol 2016; 47:38-51. [PMID: 27045194 DOI: 10.1080/10826068.2016.1163579] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Cell separation techniques play an indispensable part in numerous basic biological studies and even clinical settings. Although various cell isolation methods with diverse applications have been devised so far, not all of them have been able to gain widespread popularity among researchers and clinicians. There is not a single method known to be advantageous over all cell isolation techniques, and in fact, it is the researcher's aim in performing a study that determines the most suitable method. A perfect method for one study might not be necessarily a proper choice for another and likewise, expensive and complex isolation methods might not always be the best choices. There are several criteria such as cell purity, viability, activation status, and frequency that need to be given serious thought before selecting an isolation technique. Moreover, time and cost are two of the key elements that should be taken into consideration before implementing a project. Hence, here we provide a succinct description of six more popular cell separation methods with respect to their principles, advantages, and disadvantages as well as their most common applications. We further provide several key features of each technique so that it helps the researchers to take the first step toward opting for the best method that fits well into their projects.
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Affiliation(s)
- Narges Rahmanian
- a Department of Molecular Medicine, School of Advanced Technologies in Medicine , Tehran University of Medical Sciences , Tehran , Iran
| | - Mohmood Bozorgmehr
- b Oncopathology Research Center , Iran University of Medical Sciences , Tehran , Iran
| | - Monir Torabi
- c Department of Pathology, Shariati Hospital , Tehran University of Medical Sciences , Tehran , Iran
| | - Abolfazl Akbari
- d Colorectal Research Center , Iran University of Medical Sciences , Tehran , Iran
| | - Amir-Hassan Zarnani
- e Department of Immunology , School of Public Health, Tehran University of Medical Sciences , Tehran , Iran.,f Immunology Research Center , Iran University of Medical Sciences , Tehran , Iran
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52
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Kotzur M, König L, Egner S. Entwicklung und Anpassung einer Free-Flow-Elektrophorese zur selektiven quantitativen Trennung von Metallionen. CHEM-ING-TECH 2016. [DOI: 10.1002/cite.201400155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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53
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Continuous particle separation using pressure-driven flow-induced miniaturizing free-flow electrophoresis (PDF-induced μ-FFE). Sci Rep 2016; 6:19911. [PMID: 26819221 PMCID: PMC4730231 DOI: 10.1038/srep19911] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 12/21/2015] [Indexed: 12/24/2022] Open
Abstract
In this paper, we introduce pressure-driven flow-induced miniaturizing free-flow electrophoresis (PDF-induced μ-FFE), a novel continuous separation method. In our separation system, the external flow and electric field are applied to particles, such that particle movement is affected by pressure-driven flow, electroosmosis, and electrophoresis. We then analyzed the hydrodynamic drag force and electrophoretic force applied to the particles in opposite directions. Based on this analysis, micro- and nano-sized particles were separated according to their electrophoretic mobilities with high separation efficiency. Because the separation can be achieved in a simple T-shaped microchannel, without the use of internal electrodes, it offers the advantages of low-cost, simple device fabrication and bubble-free operation, compared with conventional μ-FFE methods. Therefore, we expect the proposed separation method to have a wide range of filtering/separation applications in biochemical analysis.
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54
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Park JK, Campos CDM, Neužil P, Abelmann L, Guijt RM, Manz A. Direct coupling of a free-flow isotachophoresis (FFITP) device with electrospray ionization mass spectrometry (ESI-MS). LAB ON A CHIP 2015; 15:3495-3502. [PMID: 26183237 DOI: 10.1039/c5lc00523j] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We present the online coupling of a free-flow isotachophoresis (FFITP) device to an electrospray ionization mass spectrometer (ESI-MS) for continuous analysis without extensive sample preparation. Free-flow-electrophoresis techniques are used for continuous electrophoretic separations using an electric field applied perpendicular to the buffer and sample flow, with FFITP using a discontinuous electrolyte system to concurrently focus a target analyte and remove interferences. The online coupling of FFITP to ESI-MS decouples the separation and detection timeframe because the electrophoretic separation takes place perpendicular to the flow direction, which can be beneficial for monitoring (bio)chemical changes and/or extensive MS(n) studies. We demonstrated the coupling of FFITP with ESI-MS for simultaneous concentration of target analytes and sample clean-up. Furthermore, we show hydrodynamic control of the fluidic fraction injected into the MS, allowing for fluidically controlled scanning of the ITP window. Future applications of this approach are expected in monitoring biochemical changes and proteomics.
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Affiliation(s)
- J K Park
- Korea Institute of Science and Technology (KIST)-Europe, Campus e 7 1, 66123, Germany.
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55
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Dutta D. An analytic description of electrodynamic dispersion in free-flow zone electrophoresis. J Chromatogr A 2015; 1404:124-30. [PMID: 26044384 DOI: 10.1016/j.chroma.2015.05.035] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Revised: 05/12/2015] [Accepted: 05/17/2015] [Indexed: 01/11/2023]
Abstract
The present work analyzes the electrodynamic dispersion of sample streams in a free-flow zone electrophoresis (FFZE) chamber resulting due to partial or complete blockage of electroosmotic flow (EOF) across the channel width by the sidewalls of the conduit. This blockage of EOF has been assumed to generate a pressure-driven backflow in the transverse direction for maintaining flow balance in the system. A parallel-plate based FFZE device with the analyte stream located far away from the channel side regions has been considered to simplify the current analysis. Applying a method-of-moments formulation, an analytic expression was derived for the variance of the sample zone at steady state as a function of its position in the separation chamber under these conditions. It has been shown that the increase in stream broadening due to the electrodynamic dispersion phenomenon is additive to the contributions from molecular diffusion and sample injection, and simply modifies the coefficient for the hydrodynamic dispersion term for a fixed lateral migration distance of the sample stream. Moreover, this dispersion mechanism can dominate the overall spatial variance of analyte zones when a significant fraction of the EOF is blocked by the channel sidewalls. The analysis also shows that analyte streams do not undergo any hydrodynamic broadening due to unwanted pressure-driven cross-flows in an FFZE chamber in the absence of a transverse electric field. The noted results have been validated using Monte Carlo simulations which further demonstrate that while the sample concentration profile at the channel outlet approaches a Gaussian distribution only in FFZE chambers substantially longer than the product of the axial pressure-driven velocity and the characteristic diffusion time in the system, the spatial variance of the exiting analyte stream is well described by the Taylor-Aris dispersion limit even in analysis ducts much shorter than this length scale.
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Affiliation(s)
- Debashis Dutta
- Department of Chemistry, (Dept. # 3838), University of Wyoming, 1000 East University Avenue, Laramie, WY 82071 USA.
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56
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Target protein separation and preparation by free-flow electrophoresis coupled with charge-to-mass ratio analysis. J Chromatogr A 2015; 1397:73-80. [DOI: 10.1016/j.chroma.2015.04.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 04/01/2015] [Accepted: 04/04/2015] [Indexed: 11/15/2022]
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57
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Timm C, Niemeyer CM. Assembly and Purification of Enzyme-Functionalized DNA Origami Structures. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201500175] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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58
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Timm C, Niemeyer CM. Assembly and Purification of Enzyme-Functionalized DNA Origami Structures. Angew Chem Int Ed Engl 2015; 54:6745-50. [DOI: 10.1002/anie.201500175] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Revised: 03/07/2015] [Indexed: 12/28/2022]
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59
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Poehler E, Herzog C, Suendermann M, Pfeiffer SA, Nagl S. Development of microscopic time-domain dual lifetime referencing luminescence detection for pH monitoring in microfluidic free-flow isoelectric focusing. Eng Life Sci 2015. [DOI: 10.1002/elsc.201400081] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Affiliation(s)
- Elisabeth Poehler
- Institut für Analytische Chemie; Universität Leipzig; Leipzig Germany
| | - Christin Herzog
- Institut für Analytische Chemie; Universität Leipzig; Leipzig Germany
| | | | - Simon A. Pfeiffer
- Institut für Analytische Chemie; Universität Leipzig; Leipzig Germany
| | - Stefan Nagl
- Institut für Analytische Chemie; Universität Leipzig; Leipzig Germany
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60
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Kinde TF, Lopez TD, Dutta D. Electrophoretic extraction of low molecular weight cationic analytes from sodium dodecyl sulfate containing sample matrices for their direct electrospray ionization mass spectrometry. Anal Chem 2015; 87:2702-9. [PMID: 25664891 PMCID: PMC4455540 DOI: 10.1021/ac503903j] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
While the use of sodium dodecyl sulfate (SDS) in separation buffers allows efficient analysis of complex mixtures, its presence in the sample matrix is known to severely interfere with the mass-spectrometric characterization of analyte molecules. In this article, we report a microfluidic device that addresses this analytical challenge by enabling inline electrospray ionization mass spectrometry (ESI-MS) of low molecular weight cationic samples prepared in SDS containing matrices. The functionality of this device relies on the continuous extraction of analyte molecules into an SDS-free solvent stream based on the free-flow zone electrophoresis (FFZE) technique prior to their ESI-MS analysis. The reported extraction was accomplished in our current work in a glass channel with microelectrodes fabricated along its sidewalls to realize the desired electric field. Our experiments show that a key challenge to successfully operating such a device is to suppress the electroosmotically driven fluid circulations generated in its extraction channel that otherwise tend to vigorously mix the liquid streams flowing through this duct. A new coating medium, N-(2-triethoxysilylpropyl) formamide, recently demonstrated by our laboratory to nearly eliminate electroosmotic flow in glass microchannels was employed to address this issue. Applying this surface modifier, we were able to efficiently extract two different peptides, human angiotensin I and MRFA, individually from an SDS containing matrix using the FFZE method and detect them at concentrations down to 3.7 and 6.3 μg/mL, respectively, in samples containing as much as 10 mM SDS. Notice that in addition to greatly reducing the amount of SDS entering the MS instrument, the reported approach allows rapid solvent exchange for facilitating efficient analyte ionization desired in ESI-MS analysis.
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Affiliation(s)
- Tristan F. Kinde
- Department of Chemistry, University of Wyoming, Laramie, Wyoming 82071, United States
| | - Thomas D. Lopez
- Department of Chemistry, University of Wyoming, Laramie, Wyoming 82071, United States
| | - Debashis Dutta
- Department of Chemistry, University of Wyoming, Laramie, Wyoming 82071, United States
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61
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Benz C, Boomhoff M, Appun J, Schneider C, Belder D. Chip-Based Free-Flow Electrophoresis with Integrated Nanospray Mass-Spectrometry. Angew Chem Int Ed Engl 2015; 54:2766-70. [DOI: 10.1002/anie.201409663] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 11/12/2014] [Indexed: 11/07/2022]
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62
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Benz C, Boomhoff M, Appun J, Schneider C, Belder D. Chip-basierte Freiflusselektrophorese mit integrierter Nanospray-Massenspektrometrie-Kopplung. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201409663] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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63
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Poehler E, Herzog C, Lotter C, Pfeiffer SA, Aigner D, Mayr T, Nagl S. Label-free microfluidic free-flow isoelectric focusing, pH gradient sensing and near real-time isoelectric point determination of biomolecules and blood plasma fractions. Analyst 2015; 140:7496-502. [DOI: 10.1039/c5an01345c] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Continuous biomolecular separation and pH gradient observation using UV and NIR fluorescence.
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Affiliation(s)
- Elisabeth Poehler
- Institut für Analytische Chemie
- Universität Leipzig
- 04103 Leipzig
- Germany
| | - Christin Herzog
- Institut für Analytische Chemie
- Universität Leipzig
- 04103 Leipzig
- Germany
| | - Carsten Lotter
- Institut für Analytische Chemie
- Universität Leipzig
- 04103 Leipzig
- Germany
| | - Simon A. Pfeiffer
- Institut für Analytische Chemie
- Universität Leipzig
- 04103 Leipzig
- Germany
| | - Daniel Aigner
- Institut für Analytische Chemie und Lebensmittelchemie
- Technische Universität Graz
- 8010 Graz
- Austria
| | - Torsten Mayr
- Institut für Analytische Chemie und Lebensmittelchemie
- Technische Universität Graz
- 8010 Graz
- Austria
| | - Stefan Nagl
- Institut für Analytische Chemie
- Universität Leipzig
- 04103 Leipzig
- Germany
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64
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Herling TW, Arosio P, Müller T, Linse S, Knowles TPJ. A microfluidic platform for quantitative measurements of effective protein charges and single ion binding in solution. Phys Chem Chem Phys 2015; 17:12161-7. [DOI: 10.1039/c5cp00746a] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Microfluidic electrophoresis enables the comparison of dry sequence and solvated protein charges, and the detection of protein–ion binding.
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Affiliation(s)
| | - Paolo Arosio
- Department of Chemistry
- University of Cambridge
- Cambridge
- UK
| | - Thomas Müller
- Department of Chemistry
- University of Cambridge
- Cambridge
- UK
| | - Sara Linse
- Department of Biochemistry and Structural Biology
- Lund University
- Lund
- Sweden
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65
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66
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Herzog C, Beckert E, Nagl S. Rapid Isoelectric Point Determination in a Miniaturized Preparative Separation Using Jet-Dispensed Optical pH Sensors and Micro Free-Flow Electrophoresis. Anal Chem 2014; 86:9533-9. [DOI: 10.1021/ac501783r] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Christin Herzog
- Institut
für Analytische Chemie, Universität Leipzig, Linnéstrasse
3, 04103 Leipzig, Germany
| | - Erik Beckert
- Fraunhofer-Institut für Angewandte Optik und Feinmechanik (IOF), Albert-Einstein-Strasse 7, 07745 Jena, Germany
| | - Stefan Nagl
- Institut
für Analytische Chemie, Universität Leipzig, Linnéstrasse
3, 04103 Leipzig, Germany
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67
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Zhang F, Li D. A novel particle separation method based on induced-charge electro-osmotic flow and polarizability of dielectric particles. Electrophoresis 2014; 35:2922-9. [DOI: 10.1002/elps.201400194] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Revised: 06/19/2014] [Accepted: 06/30/2014] [Indexed: 01/14/2023]
Affiliation(s)
- Fang Zhang
- Department of Mechanical and Mechatronics Engineering; University of Waterloo; Waterloo Ontario Canada
| | - Dongqing Li
- Department of Mechanical and Mechatronics Engineering; University of Waterloo; Waterloo Ontario Canada
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68
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Gabrielsson EO, Janson P, Tybrandt K, Simon DT, Berggren M. A four-diode full-wave ionic current rectifier based on bipolar membranes: overcoming the limit of electrode capacity. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2014; 26:5143-7. [PMID: 24863171 DOI: 10.1002/adma.201401258] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 05/09/2014] [Indexed: 05/19/2023]
Abstract
Full-wave rectification of ionic currents is obtained by constructing the typical four-diode bridge out of ion conducting bipolar membranes. Together with conjugated polymer electrodes addressed with alternating current, the bridge allows for generation of a controlled ionic direct current for extended periods of time without the production of toxic species or gas typically arising from electrode side-reactions.
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Affiliation(s)
- Erik O Gabrielsson
- Laboratory of Organic Electronics, Linköping University, SE-601 74, Norrköping, Sweden
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69
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Dutta D. A method-of-moments formulation for describing hydrodynamic dispersion of analyte streams in free-flow zone electrophoresis. J Chromatogr A 2014; 1340:134-8. [DOI: 10.1016/j.chroma.2014.03.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2013] [Revised: 03/05/2014] [Accepted: 03/05/2014] [Indexed: 01/08/2023]
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70
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Lee HY, Barber C, Minerick AR. Improving electrokinetic microdevice stability by controlling electrolysis bubbles. Electrophoresis 2014; 35:1782-9. [DOI: 10.1002/elps.201400013] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Revised: 03/13/2014] [Accepted: 03/14/2014] [Indexed: 11/12/2022]
Affiliation(s)
- Hwi Yong Lee
- Department of Chemical Engineering; Michigan Technological University; Houghton MI USA
| | - Cedrick Barber
- Department of Chemical Engineering; Michigan Technological University; Houghton MI USA
| | - Adrienne R. Minerick
- Department of Chemical Engineering; Michigan Technological University; Houghton MI USA
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71
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Cheng LJ, Chang HC. Switchable pH actuators and 3D integrated salt bridges as new strategies for reconfigurable microfluidic free-flow electrophoretic separation. LAB ON A CHIP 2014; 14:979-87. [PMID: 24430103 DOI: 10.1039/c3lc51023a] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
We present novel strategies for reconfigurable, high-throughput microfluidic free-flow electrophoretic separation using electrically switchable pH actuators and 3D integrated salt bridges to allow rapid formation of stable pH gradients and efficient electrophoresis. The pH actuator is achieved by microfluidic integration of bipolar membranes which change electrolyte pH by injecting excess H(+) or OH(-) ions produced by a field-enhanced water dissociation phenomenon at the membrane junction upon voltage bias. The technique does not require conventional multiple buffer inflows and leaves no gas production as experienced in electrolysis, thus providing stable pH gradients for isoelectric focusing (IEF) separation. With the pH actuator inactivated, the platform can perform zone electrophoretic (ZE) separation in a medium of constant pH. We also describe the use of 3D integrated ion conductive polymers that serve as salt bridges for improving the voltage efficiency of electrophoresis and to allow high throughput. The proof of concept was successfully demonstrated for free-flow IEF and ZE separation of protein mixtures showing the potential and the simplicity of the platform for high-throughput and high-precision sample separation.
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Affiliation(s)
- Li-Jing Cheng
- School of Electrical Engineering and Computer Science, Oregon State University, OR 97331, USA.
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72
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Abdallah BG, Kupitz C, Fromme P, Ros A. Crystallization of the large membrane protein complex photosystem I in a microfluidic channel. ACS NANO 2013; 7:10534-43. [PMID: 24191698 PMCID: PMC3940344 DOI: 10.1021/nn402515q] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Traditional macroscale protein crystallization is accomplished nontrivially by exploring a range of protein concentrations and buffers in solution until a suitable combination is attained. This methodology is time-consuming and resource-intensive, hindering protein structure determination. Even more difficulties arise when crystallizing large membrane protein complexes such as photosystem I (PSI) due to their large unit cells dominated by solvent and complex characteristics that call for even stricter buffer requirements. Structure determination techniques tailored for these "difficult to crystallize" proteins such as femtosecond nanocrystallography are being developed yet still need specific crystal characteristics. Here, we demonstrate a simple and robust method to screen protein crystallization conditions at low ionic strength in a microfluidic device. This is realized in one microfluidic experiment using low sample amounts, unlike traditional methods where each solution condition is set up separately. Second harmonic generation microscopy via second-order nonlinear imaging of chiral crystals (SONICC) was applied for the detection of nanometer- and micrometer-sized PSI crystals within microchannels. To develop a crystallization phase diagram, crystals imaged with SONICC at specific channel locations were correlated to protein and salt concentrations determined by numerical simulations of the time-dependent diffusion process along the channel. Our method demonstrated that a portion of the PSI crystallization phase diagram could be reconstructed in excellent agreement with crystallization conditions determined by traditional methods. We postulate that this approach could be utilized to efficiently study and optimize crystallization conditions for a wide range of proteins that are poorly understood to date.
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73
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Ion concentration polarization-based continuous separation device using electrical repulsion in the depletion region. Sci Rep 2013; 3:3483. [PMID: 24352563 PMCID: PMC6506453 DOI: 10.1038/srep03483] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Accepted: 11/15/2013] [Indexed: 12/21/2022] Open
Abstract
We proposed a novel separation method, which is the first report using ion concentration polarization (ICP) to separate particles continuously. We analyzed the electrical forces that cause the repulsion of particles in the depletion region formed by ICP. Using the electrical repulsion, micro- and nano-sized particles were separated based on their electrophoretic mobilities. Because the separation of particles was performed using a strong electric field in the depletion region without the use of internal electrodes, it offers the advantages of simple, low-cost device fabrication and bubble-free operation compared with conventional continuous electrophoretic separation methods, such as miniaturizing free-flow electrophoresis (μ-FFE). This separation device is expected to be a useful tool for separating various biochemical samples, including cells, proteins, DNAs and even ions.
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74
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Song YA, Wu L, Tannenbaum SR, Wishnok JS, Han J. Tunable membranes for free-flow zone electrophoresis in PDMS microchip using guided self-assembly of silica microbeads. Anal Chem 2013; 85:11695-9. [PMID: 24251795 DOI: 10.1021/ac402169x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In this paper, we evaluate the strategy of using self-assembled microbeads to build a robust and tunable membrane for free-flow zone electrophoresis in a PDMS microfluidic chip. To fabricate a porous membrane as a salt bridge for free-flow zone electrophoresis, we used silica or polystyrene microbeads between 3-6 μm in diameter and packed them inside a microchannel. After complete evaporation, we infiltrated the porous microbead structure with a positively or negatively charged hydrogel to modify its surface charge polarity. Using this device, we demonstrated binary sorting (separation of positive and negative species at a given pH) of peptides and dyes in standard buffer systems without using sheath flows. The sample loss during sorting could be minimized by using ion selectivity of hydrogel-infiltrated microbead membranes. Our fabrication method enables building a robust membrane for pressure-driven free-flow zone electrophoresis with tunable pore size as well as surface charge polarity.
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Affiliation(s)
- Yong-Ak Song
- Department of Electrical Engineering and Computer Science, ‡Department of Biological Engineering, §Department of Chemistry, Massachusetts Institute of Technology , 77 Massachusetts Avenue, Cambridge, MA 02139, United States
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75
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Zhou J, Kasper S, Papautsky I. Enhanced size-dependent trapping of particles using microvortices. MICROFLUIDICS AND NANOFLUIDICS 2013; 15:10.1007/s10404-013-1176-y. [PMID: 24187531 PMCID: PMC3810988 DOI: 10.1007/s10404-013-1176-y] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Inertial microfluidics has been attracting considerable interest for size-based separation of particles and cells. The inertial forces can be manipulated by expanding the microchannel geometry, leading to formation of microvortices which selectively isolate and trap particles or cells from a mixture. In this work, we aim to enhance our understanding of particle trapping in such microvortices by developing a model of selective particle trapping. Design and operational parameters including flow conditions, size of the trapping region, and target particle concentration are explored to elucidate their influence on trapping behavior. Our results show that the size dependence of trapping is characterized by a threshold Reynolds number, which governs the selective entry of particles into microvortices from the main flow. We show that concentration enhancement on the order of 100,000× and isolation of targets at concentrations in the 1/mL is possible. Ultimately, the insights gained from our systematic investigation suggest optimization solutions that enhance device performance (efficiency, size selectivity, and yield) and are applicable to selective isolation and trapping of large rare cells as well as other applications.
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Affiliation(s)
- Jian Zhou
- BioMicroSystems Lab, School of Electronic and Computing Systems, University of Cincinnati
| | - Susan Kasper
- Department of Environmental Health, College of Medicine, University of Cincinnati
| | - Ian Papautsky
- BioMicroSystems Lab, School of Electronic and Computing Systems, University of Cincinnati
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76
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Gitlin L, Hoera C, Meier RJ, Nagl S, Belder D. Micro flow reactor chips with integrated luminescent chemosensors for spatially resolved on-line chemical reaction monitoring. LAB ON A CHIP 2013; 13:4134-41. [PMID: 23970303 DOI: 10.1039/c3lc50387a] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Real-time chemical reaction monitoring in microfluidic environments is demonstrated using luminescent chemical sensors integrated in PDMS/glass-based microscale reactors. A fabrication procedure is presented that allows for straightforward integration of thin polymer layers with optical sensing functionality in microchannels of glass-PDMS chips of only 150 μm width and of 10 to 35 μm height. Sensor layers consisting of polystyrene and an oxygen-sensitive platinum porphyrin probe with film thicknesses of about 0.5 to 4 μm were generated by combining spin coating and abrasion techniques. Optimal coating procedures were developed and evaluated. The chip-integrated sensor layers were calibrated and investigated with respect to stability, reproducibility and response times. These microchips allowed observation of dissolved oxygen concentration in the range of 0 to over 40 mg L(-1) with a detection limit of 368 μg L(-1). The sensor layers were then used for observation of a model reaction, the oxidation of sulphite to sulphate in a microfluidic chemical reactor and could observe sulphite concentrations of less than 200 μM. Real-time on-line monitoring of this chemical reaction was realized at a fluorescence microscope setup with 405 nm LED excitation and CCD camera detection.
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Affiliation(s)
- Leonid Gitlin
- Institut für Analytische Chemie, Universität Leipzig, Johannisallee 29, 04103 Leipzig, Germany.
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77
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Yin XY, Dong JY, Wang HY, Li S, Fan LY, Cao CX. A simple chip free-flow electrophoresis for monosaccharide sensing via supermolecule interaction of boronic acid functionalized quencher and fluorescent dye. Electrophoresis 2013; 34:2185-92. [DOI: 10.1002/elps.201300104] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2013] [Revised: 04/07/2013] [Accepted: 04/17/2013] [Indexed: 11/09/2022]
Affiliation(s)
- Xiao-Yang Yin
- Laboratory of Bio-Separation and Analytical Biochemistry; State Key Laboratory of Microbial Metabolism and School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai; P. R. China
| | | | - Hou-Yu Wang
- Laboratory of Bio-Separation and Analytical Biochemistry; State Key Laboratory of Microbial Metabolism and School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai; P. R. China
| | - Si Li
- Laboratory of Bio-Separation and Analytical Biochemistry; State Key Laboratory of Microbial Metabolism and School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai; P. R. China
| | - Liu-Yin Fan
- Laboratory of Bio-Separation and Analytical Biochemistry; State Key Laboratory of Microbial Metabolism and School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai; P. R. China
| | - Cheng-Xi Cao
- Laboratory of Bio-Separation and Analytical Biochemistry; State Key Laboratory of Microbial Metabolism and School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai; P. R. China
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78
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Smejkal P, Bottenus D, Breadmore MC, Guijt RM, Ivory CF, Foret F, Macka M. Microfluidic isotachophoresis: A review. Electrophoresis 2013; 34:1493-509. [DOI: 10.1002/elps.201300021] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Revised: 03/06/2013] [Accepted: 03/07/2013] [Indexed: 12/22/2022]
Affiliation(s)
- Petr Smejkal
- ACROSS and School of Chemistry; University of Tasmania; Hobart; Australia
| | - Danny Bottenus
- Voiland School of Chemical Engineering and Bioengineering; Washington State University; Pullman; WA; USA
| | | | - Rosanne M. Guijt
- ACROSS and School of Pharmacy; University of Tasmania; Hobart; Australia
| | - Cornelius F. Ivory
- Voiland School of Chemical Engineering and Bioengineering; Washington State University; Pullman; WA; USA
| | - František Foret
- Institute of Analytical Chemistry of the Academy of Sciences of the Czech Republic; v.v.i., Brno; Czech Republic
| | - Mirek Macka
- ACROSS and School of Chemistry; University of Tasmania; Hobart; Australia
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79
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Jezierski S, Klein AS, Benz C, Schaefer M, Nagl S, Belder D. Towards an integrated device that utilizes adherent cells in a micro-free-flow electrophoresis chip to achieve separation and biosensing. Anal Bioanal Chem 2013; 405:5381-6. [PMID: 23591645 DOI: 10.1007/s00216-013-6945-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2013] [Revised: 03/16/2013] [Accepted: 03/25/2013] [Indexed: 11/28/2022]
Abstract
We immobilized adherent human embryonic kidney (HEK) cells--which are able to trace adenosine triphosphate (ATP)--inside a microfluidic free-flow electrophoresis (μFFE) chip in order to develop an integrated device combining separation and biosensing capabilities. HEK 293 cells loaded with fluorescent calcium indicators were used as a model system to enable the spatially and temporally resolved detection of ATP. The local position of a 20 μM ATP stream was successfully visualized by these cells during free-flow electrophoresis, demonstrating the on-line detection capability of this technique towards native, unlabeled compounds.
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Affiliation(s)
- Stefan Jezierski
- Institut für Analytische Chemie, Universität Leipzig, Johannisallee 29, 04103 Leipzig, Germany
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80
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Huft J, Haynes CA, Hansen CL. Microfluidic Integration of Parallel Solid-Phase Liquid Chromatography. Anal Chem 2013; 85:2999-3005. [DOI: 10.1021/ac400163u] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jens Huft
- Centre for High-Throughput Biology, University of British Columbia, Vancouver BC, Canada
- Department of Electrical and
Computer Engineering, University of British Columbia, Vancouver BC, Canada
| | - Charles A. Haynes
- Department
of Chemical and Biological
Engineering, University of British Columbia, Vancouver BC, Canada
| | - Carl L. Hansen
- Centre for High-Throughput Biology, University of British Columbia, Vancouver BC, Canada
- Department
of Physics and Astronomy, University of British Columbia, Vancouver BC, Canada
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81
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Patel S, Qian S, Xuan X. Reservoir-based dielectrophoresis for microfluidic particle separation by charge. Electrophoresis 2013; 34:961-8. [DOI: 10.1002/elps.201200467] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Revised: 10/05/2012] [Accepted: 10/05/2012] [Indexed: 12/28/2022]
Affiliation(s)
- Saurin Patel
- Department of Mechanical Engineering; Clemson University; Clemson; SC; USA
| | | | - Xiangchun Xuan
- Department of Mechanical Engineering; Clemson University; Clemson; SC; USA
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82
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Paturzo M, Finizio A, Memmolo P, Puglisi R, Balduzzi D, Galli A, Ferraro P. Microscopy imaging and quantitative phase contrast mapping in turbid microfluidic channels by digital holography. LAB ON A CHIP 2012; 12:3073-3076. [PMID: 22740323 DOI: 10.1039/c2lc40114b] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We show that sharp imaging and quantitative phase-contrast microcopy is possible in microfluidics in flowing turbid media by digital holography. In fact, in flowing liquids with suspended colloidal particles, clear vision is hindered and cannot be recovered by any other microscopic imaging technique. On the contrary, using digital holography, clear imaging is possible thanks to the Doppler frequency shift experienced by the photons scattered by the flowing colloidal particles, which do not contribute to the interference process, i.e. the recorded hologram. The method is illustrated and imaging results are demonstrated for pure phase objects, i.e. biological cells in microfluidic channels.
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Affiliation(s)
- Melania Paturzo
- CNR-National Institute of Optics, Via Campi Flegrei, 34, I-80078, Pozzuoli (NA), Italy.
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83
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Prest JE, Baldock SJ, Fielden PR, Goddard NJ, Goodacre R, O’Connor R, Treves Brown BJ. Miniaturised free flow isotachophoresis of bacteria using an injection moulded separation device. J Chromatogr B Analyt Technol Biomed Life Sci 2012; 903:53-9. [DOI: 10.1016/j.jchromb.2012.06.040] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Revised: 06/29/2012] [Accepted: 06/30/2012] [Indexed: 11/25/2022]
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84
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Shao J, Fan LY, Cao CX, Huang XQ, Xu YQ. Quantitative investigation of resolution increase of free-flow electrophoresis via simple interval sample injection and separation. Electrophoresis 2012; 33:2065-74. [DOI: 10.1002/elps.201200169] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- Jing Shao
- Laboratory of Bio-separation and Analytical Biochemistry; State Key Laboratory of Microbial Metabolism; School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai; China
| | - Liu-Yin Fan
- Laboratory of Bio-separation and Analytical Biochemistry; State Key Laboratory of Microbial Metabolism; School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai; China
| | - Cheng-Xi Cao
- Laboratory of Bio-separation and Analytical Biochemistry; State Key Laboratory of Microbial Metabolism; School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai; China
| | - Xian-Qing Huang
- Laboratory of Bio-separation and Analytical Biochemistry; State Key Laboratory of Microbial Metabolism; School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai; China
| | - Yu-Quan Xu
- Laboratory of Bio-separation and Analytical Biochemistry; State Key Laboratory of Microbial Metabolism; School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai; China
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85
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Pang B, Shao J, Zhang J, Geng JZ, Fan LY, Cao CX, Hou JL. Enhancing separation of histidine from amino acids via free-flow affinity electrophoresis with gravity-induced uniform hydrodynamic flow. Electrophoresis 2012; 33:856-65. [DOI: 10.1002/elps.201100494] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Bo Pang
- Laboratory of Bioseparation and Analytical Biochemistry; State Key Laboratory of Microbial Metabolism; School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai; China
| | - Jing Shao
- Laboratory of Bioseparation and Analytical Biochemistry; State Key Laboratory of Microbial Metabolism; School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai; China
| | - Jie Zhang
- Laboratory of Bioseparation and Analytical Biochemistry; State Key Laboratory of Microbial Metabolism; School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai; China
| | - Jia-Zhen Geng
- Laboratory of Bioseparation and Analytical Biochemistry; State Key Laboratory of Microbial Metabolism; School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai; China
| | - Liu-Yin Fan
- Laboratory of Bioseparation and Analytical Biochemistry; State Key Laboratory of Microbial Metabolism; School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai; China
| | - Cheng-Xi Cao
- Laboratory of Bioseparation and Analytical Biochemistry; State Key Laboratory of Microbial Metabolism; School of Life Science and Biotechnology; Shanghai Jiao Tong University; Shanghai; China
| | - Jing-Li Hou
- Instrumental Analysis Center; Shanghai Jiao Tong University; Shanghai; China
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86
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Köhler S, Nagl S, Fritzsche S, Belder D. Label-free real-time imaging in microchip free-flow electrophoresis applying high speed deep UV fluorescence scanning. LAB ON A CHIP 2012; 12:458-463. [PMID: 22011722 DOI: 10.1039/c1lc20558g] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We report on label-free monitoring of microfluidic free-flow electrophoresis (μFFE) separations in real-time using a custom built high speed deep UV laser scanner. In combination with a novel layout realized in fused silica (FS) FFE chips the setup was successfully applied for continuous separations and detection of unlabeled analytes including native proteins by space-resolved intrinsic deep UV fluorescence scanning.
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Affiliation(s)
- Stefan Köhler
- Institute of Analytical Chemistry, University of Leipzig, Linnéstr. 3, 04103 Leipzig, Germany
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87
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Morales MC, Lin H, Zahn JD. Continuous microfluidic DNA and protein trapping and concentration by balancing transverse electrokinetic forces. LAB ON A CHIP 2012; 12:99-108. [PMID: 22045330 DOI: 10.1039/c1lc20605b] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Sample pre-concentration can be a critical element to improve sensitivity of integrated microchip assays. In this work a converging Y-inlet microfluidic channel with integrated coplanar electrodes was used to investigate transverse DNA and protein migration under uniform direct current (DC) electric fields to assess the ability to concentrate a sample prior to other enzymatic modifications or capillary electrophoretic separations. Employing a pressure-driven flow to perfuse the microchannel, negatively charged samples diluted in low and high ionic strength buffers were co-infused with a receiving buffer of the same ionic strength into a main daughter channel. Experimental results demonstrated that, depending of the buffer selection, different DNA migration and accumulation dynamics were seen. Charged analytes could traverse the channel width and accumulate at the positive bias electrode in a low electroosmotic mobility, high electrophoretic mobility, high ionic strength buffer or migrated towards an equilibrium position within the channel in a high electroosmotic mobility, high electrophoretic mobility, low ionic strength buffer. The various migration behaviours are the result of a balance between the electrophoretic force and a drag force induced by a recirculating electroosmotic flow generated across the channel width due to the bounding walls. Under continuous flow conditions, DNA samples were concentrated several-fold by balancing these transverse electrokinetic forces. The electrokinetic trapping technique presented here is a simple technique which could be expanded to concentrate or separate other analytes as a preconditioning step for downstream processes.
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Affiliation(s)
- Mercedes C Morales
- BioMEMS Laboratory, Department of Biomedical Engineering, Rutgers, The State University of New Jersey, 599 Taylor Road, Piscataway, New Jersey 08854, USA
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88
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Ding H, Li X, Lv X, Xu J, Sun X, Zhang Z, Wang H, Deng Y. Fabrication of micro free-flow electrophoresis chip by photocurable monomer binding microfabrication technique for continuous separation of proteins and their numerical simulation. Analyst 2012; 137:4482-9. [DOI: 10.1039/c2an35535c] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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89
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Shkolnikov V, Bahga SS, Santiago JG. Desalination and hydrogen, chlorine, and sodium hydroxide production via electrophoretic ion exchange and precipitation. Phys Chem Chem Phys 2012; 14:11534-45. [DOI: 10.1039/c2cp42121f] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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90
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Köhler S, Benz C, Becker H, Beckert E, Beushausen V, Belder D. Micro free-flow electrophoresis with injection molded chips. RSC Adv 2012. [DOI: 10.1039/c1ra00874a] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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91
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Geng JZ, Shao J, Yang JH, Pang B, Cao CX, Fan LY. Reassemblable quasi-chip free-flow electrophoresis with simple heating dispersion for rapid micropreparation of trypsin in crude porcine pancreatin. Electrophoresis 2011; 32:3248-56. [DOI: 10.1002/elps.201100358] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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92
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Walowski B, Hüttner W, Wackerbarth H. Generation of a miniaturized free-flow electrophoresis chip based on a multi-lamination technique—isoelectric focusing of proteins and a single-stranded DNA fragment. Anal Bioanal Chem 2011; 401:2465-71. [DOI: 10.1007/s00216-011-5353-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Revised: 08/18/2011] [Accepted: 08/19/2011] [Indexed: 12/01/2022]
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93
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Abstract
Micro free flow electrophoresis (micro-FFE) is a continuous micro-separation or preparation technique, which has been applied in the analysis of biomolecules, such as cells, sub cell organics and proteins. In this review, the recent progresses in micro FFE are summarized, with emphasis on the design of microchips, the separation modes and the applications of micro-FFE. Furthermore, the further developments of micro-FFE are prospected.
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Affiliation(s)
- Pingli Wang
- National Chromatographic R. & A. Center, Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
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94
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Dong YC, Shao J, Yin XY, Fan LY, Cao CX. Mid-scale free-flow electrophoresis with gravity-induced uniform flow of background buffer in chamber for the separation of cells and proteins. J Sep Sci 2011; 34:1683-91. [DOI: 10.1002/jssc.201100293] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Revised: 04/29/2011] [Accepted: 04/29/2011] [Indexed: 01/22/2023]
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95
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Köhler S, Weilbeer C, Howitz S, Becker H, Beushausen V, Belder D. PDMS free-flow electrophoresis chips with integrated partitioning bars for bubble segregation. LAB ON A CHIP 2011; 11:309-14. [PMID: 21060908 DOI: 10.1039/c0lc00347f] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
In this work, a microfluidic free-flow electrophoresis device with a novel approach for preventing gas bubbles from entering the separation area is presented. This is achieved by integrating partitioning bars to reduce the channel depth between electrode channels and separation chamber in order to obtain electrical contact and simultaneously prevent bubbles from entering the separation area. The three-layer sandwich chip features a reusable carrier plate with integrated ports for fluidic connection combined with a softlithographically cast microfluidic PDMS layer and a sealing glass slide. This design allows for a straightforward and rapid chip prototyping process. The performance of the device is demonstrated by free-flow zone electrophoretic separations of fluorescent dye mixtures as well as by the separation of labeled amines and amino acids with separation voltages up to 297 V.
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Affiliation(s)
- Stefan Köhler
- Institute of Analytical Chemistry, University of Leipzig, Linnéstr. 3, 04103, Leipzig, Germany
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96
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de Oliveira JMPF, de Graaff LH. Proteomics of industrial fungi: trends and insights for biotechnology. Appl Microbiol Biotechnol 2010; 89:225-37. [PMID: 20922379 PMCID: PMC3016146 DOI: 10.1007/s00253-010-2900-0] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Revised: 09/17/2010] [Accepted: 09/18/2010] [Indexed: 12/01/2022]
Abstract
Filamentous fungi are widely known for their industrial applications, namely, the production of food-processing enzymes and metabolites such as antibiotics and organic acids. In the past decade, the full genome sequencing of filamentous fungi increased the potential to predict encoded proteins enormously, namely, hydrolytic enzymes or proteins involved in the biosynthesis of metabolites of interest. The integration of genome sequence information with possible phenotypes requires, however, the knowledge of all the proteins in the cell in a system-wise manner, given by proteomics. This review summarises the progress of proteomics and its importance for the study of biotechnological processes in filamentous fungi. A major step forward in proteomics was to couple protein separation with high-resolution mass spectrometry, allowing accurate protein quantification. Despite the fact that most fungal proteomic studies have been focused on proteins from mycelial extracts, many proteins are related to processes which are compartmentalised in the fungal cell, e.g. β-lactam antibiotic production in the microbody. For the study of such processes, a targeted approach is required, e.g. by organelle proteomics. Typical workflows for sample preparation in fungal organelle proteomics are discussed, including homogenisation and sub-cellular fractionation. Finally, examples are presented of fungal organelle proteomic studies, which have enlarged the knowledge on areas of interest to biotechnology, such as protein secretion, energy production or antibiotic biosynthesis.
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Affiliation(s)
- José Miguel P Ferreira de Oliveira
- Fungal Systems Biology, Laboratory of Systems and Synthetic Biology, Wageningen University, Dreijenplein 10, NL-6703 HB, Wageningen, The Netherlands
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97
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Wen J, Albrecht JW, Jensen KF. Microfluidic preparative free-flow isoelectric focusing in a triangular channel: system development and characterization. Electrophoresis 2010; 31:1606-14. [PMID: 20419703 DOI: 10.1002/elps.200900577] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A preparative scale free-flow IEF device is developed and characterized with the aim of addressing needs of molecular biologists working with protein samples on the milligrams and milliliters scale. A triangular-shape separation channel facilitates the establishment of the pH gradient with a corresponding increase in separation efficiency and decrease in focusing time compared with that in a regular rectangular channel. Functionalized, ion-permeable poly(acrylamide) gel membranes are sandwiched between PDMS and glass layers to both isolate the electrode buffers from the central separation channel and also to selectively adjust the voltage efficiency across the separation channel to achieve high electric field separation. The 50 x 70 mm device is fabricated by soft lithography and has 24 outlets evenly spaced across a pH gradient between pH 4 and 10. This preparative free-flow IEF system is investigated and optimized for both aqueous and denaturing conditions with respect to the electric field and potential efficiency and with consideration of Joule-heating removal. Energy distribution across the functionalized polyacrylamide gel is investigated and controlled to adjust the potential efficiency between 15 and 80% across the triangular separation channel. The device is able to achieve constant electric fields high as 370+/-20 V/cm through the entire triangular channel given the separation voltage of 1800 V, enabling separation of five fluorescent pI markers as a demonstration example.
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Affiliation(s)
- Jian Wen
- Department of Chemical Engineering, Massachusetts Institute of Technology, MA 02139, USA
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98
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Non-orthogonal micro-free flow electrophoresis: From theory to design concept. Anal Chim Acta 2010; 674:102-9. [DOI: 10.1016/j.aca.2010.06.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2010] [Revised: 05/28/2010] [Accepted: 06/01/2010] [Indexed: 11/22/2022]
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99
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Song YA, Chan M, Celio C, Tannenbaum SR, Wishnok JS, Han J. Free-flow zone electrophoresis of peptides and proteins in PDMS microchip for narrow pI range sample prefractionation coupled with mass spectrometry. Anal Chem 2010; 82:2317-25. [PMID: 20163146 DOI: 10.1021/ac9025219] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In this paper, we are evaluating the strategy of sorting peptides/proteins based on the charge to mass without resorting to ampholytes and/or isoelectric focusing, using a single- and two-step free-flow zone electrophoresis. We developed a simple fabrication method to create a salt bridge for free-flow zone electrophoresis in PDMS chips by surface printing a hydrophobic layer on a glass substrate. Since the surface-printed hydrophobic layer prevents plasma bonding between the PDMS chip and the substrate, an electrical junction gap can be created for free-flow zone electrophoresis. With this device, we demonstrated a separation of positive and negative peptides and proteins at a given pH in standard buffer systems and validated the sorting result with LC/MS. Furthermore, we coupled two sorting steps via off-chip titration and isolated peptides within specific pI ranges from sample mixtures, where the pI range was simply set by the pH values of the buffer solutions. This free-flow zone electrophoresis sorting device, with its simplicity of fabrication, and a sorting resolution of 0.5 pH unit, can potentially be a high-throughput sample fractionation tool for targeted proteomics using LC/MS.
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Affiliation(s)
- Yong-Ak Song
- Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA
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100
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Santos HM, Lodeiro C, Capelo J. Analytical Proteomics: An emerging field? J Proteomics 2010; 73:1411-4. [DOI: 10.1016/j.jprot.2010.03.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2010] [Accepted: 03/19/2010] [Indexed: 01/19/2023]
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