Two-Phase Electrophoresis of Biomolecules.
Technische Universität, Darmstadt
[Ph.D. Thesis], (2009)
Dissertation - Götz Münchow -
Available under Creative Commons Attribution Non-commercial No Derivatives, 2.5.
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|Item Type:||Ph.D. Thesis|
|Title:||Two-Phase Electrophoresis of Biomolecules|
Existing microfluidic separation technologies for biomolecules commonly rely on single phase liquid systems as well as on electrophoresis. But microfluidics also facilitates the generation of stable, well-controlled and immiscible liquid-liquid two-phase arrangements, since interfacial forces usually dominate over volume forces. The present work combines these approaches and reports on protein and cell transport as well as on enrichment and separation phenomena discovered in various experiments with a novel microfluidic setup for continuous-flow two-phase electrophoresis. Therefore, phase boundaries of aqueous two-phase systems are formed within a microchannel in flow direction and the characteristic partition behavior of proteins and cells is manipulated and tuned by applying an electric field perpendicular to the phase boundary. The two immiscible phases which separately are injected into a microchannel are taken from aqueous polyethylene glycol (PEG) - dextran systems. Different ways are possible to induce an electric field within a microchannel, but it was found out that electrodes have to be decoupled from the two-phase flow and especially hydrogels can be utilized as adequate ion conductors. Thus bubble generation inside the microchannel is prevented and a stable two-phase flow is guaranteed. In contrast to macroscopic systems, microfluidic setups allow detailed investigations of local effects at the phase boundary. The results of the experiments show that the diffusive as well as the electrophoretic transport behavior of proteins between the laminated liquid phases is strongly influenced by their partition coefficients. Furthermore, effects of the phase boundary itself, like electric double layers, are negligible in this case. This derived knowledge helps to design specific two-phase partition and enrichment procedures combined with electric fields for future studies. Besides a detailed examination of the transport behavior of proteins a continuous separation of proteins from cells is presented. While proteins in presence of an external electric field pass the boundary and leave the phase they have been initially dissolved in almost completely, lymphoblastoid cells can be retained, thus allowing a stable and continuous separation of these two kinds of biomolecules. And finally, further kinds of fluid combinations such as water and propylene carbonate are presented, supporting an enrichment of proteins at the phase boundary.
|Place of Publication:||Darmstadt|
|Uncontrolled Keywords:||Microfluidic Electrophoresis Aqueous Two-Phase System Interface|
|Classification DDC:||500 Naturwissenschaften und Mathematik > 540 Chemie
500 Naturwissenschaften und Mathematik > 500 Naturwissenschaften
600 Technik, Medizin, angewandte Wissenschaften > 620 Ingenieurwissenschaften
500 Naturwissenschaften und Mathematik > 570 Biowissenschaften, Biologie
|Divisions:||07 Fachbereich Chemie
10 Department of Biology
18 Fachbereich Elektrotechnik und Informationstechnik > Institut für Elektromechanische Konstruktionen > Mikrotechnik und Elektromechanische Systeme
16 Fachbereich Maschinenbau > Institut für Fluidsystemtechnik (FST)
|Date Deposited:||07 Aug 2009 09:53|
|Last Modified:||07 Dec 2012 11:55|
|Referees:||Hardt, Prof. Dr. Steffen and Kutter, Prof. Dr. Jörg Peter|
|Refereed:||17 July 2009|