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Conformational dynamics of DNA‐electrophoresis on cationic membranes
Author(s) -
Kahl Valentin,
Hennig Martin,
Maier Berenike,
Rädler Joachim O.
Publication year - 2009
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.200800430
Subject(s) - electrophoresis , membrane , lipid bilayer , chemistry , chemical physics , cationic polymerization , dna , bilayer , reptation , molecule , biophysics , gel electrophoresis , relaxation (psychology) , biological membrane , fluorescence anisotropy , analytical chemistry (journal) , chromatography , polymer , biochemistry , psychology , social psychology , organic chemistry , biology
The conformational dynamics of DNA molecules undergoing electrophoresis on a fluid substrate‐supported cationic lipid bilayer is investigated using fluorescence microscopy. At low electrophoretic velocities, drift of 2‐D random coils is observed. In contrast, at velocities larger than 0.3 μm/s, the DNA molecules stretch out and assume branched configurations. The cross‐over scenario is explained by the observation that cationic lipids segregate underneath the adsorbed DNA and confine the DNA to its counter charge imprint on time scales shorter than the relaxation time of the imprint. The concept of a tube‐like confinement of the DNA is corroborated by the observed 1/ N size dependence of the electrophoretic mobility in analogy to the biased reptation model in gels. The role of membrane defects and possible applications of membrane‐based electrophoresis in microfluidic devices are discussed.