title: Electrophoretic transport of biomolecules across liquid-liquid interfaces.
abstract: The mass transfer resistance of a liquid-liquid interface in an aqueous two-phase system composed of poly(ethylene glycol) and dextran is investigated. Different types of proteins and DNA stained with fluorescent dyes serve as probes to study the transport processes close to the interface. A microfluidic device is employed to enable the electrophoretic transport of biomolecules from one phase to another. The results obtained for proteins can be explained solely via the different electrophoretic mobilities and different affinities of the molecules to the two phases, without any indications of a significant mass transfer resistance of the liquid-liquid interface. By contrast, DNA molecules adsorb to the interface and only desorb under an increased electric field strength. The desorption process carries the signature of a thermally activated escape from a metastable state, as reflected in the exponential decay of the fluorescence intensity at the interface as a function of time.
authors.affiliation: Center of Smart Interfaces, TU Darmstadt, Darmstadt, Germany. hardt@csi.tu-darmstadt.de
authors.forename: Thomas
authors.initials: T
authors.lastname: Hahn
authors.forename: Götz
authors.initials: G
authors.lastname: Münchow
authors.forename: Steffen
authors.initials: S
authors.lastname: Hardt
mesh_terms: D000327:Adsorption; D001672:Biocompatible Materials / Q000737:chemistry*; D001692:Biological Transport; D001703:Biophysics / Q000379:methods; D004247:DNA / Q000737:chemistry*; D004563:Electrochemistry / Q000379:methods; D007477:Ions; D046210:Microfluidic Analytical Techniques; D011092:Polyethylene Glycols / Q000737:chemistry; D019904:Polymethyl Methacrylate / Q000737:chemistry; D011506:Proteins / Q000737:chemistry; D013499:Surface Properties; D014867:Water
chemical_list: D001672:Biocompatible Materials; D007477:Ions; D011506:Proteins; D014867:Water; D011092:Polyethylene Glycols; D004247:DNA; D019904:Polymethyl Methacrylate