TDAB-induced DNA plasmid condensation on the surface of a reconstructed boron doped silicon substrate

SURFACE SCIENCE

卷:602

Article

Mougin, Antoine^1,2  Babak, Valery G.³  Beche, Eric⁴  Baros, Francis⁵  Hunting, Darel J.²  Sanche, Leon²  Fromm, Michel¹ 

[1] Univ Franche Comte, LMN AC, UMR CEA E4, F-25030 Besancon, France

[2] Univ Sherbrooke, Fac Med, Ctr Res Radiooncol, Sherbrooke, PQ J1H 5N4, Canada

[3] INEOS RAS, Moscow 117813, Russia

[4] PROMES, UMR CNRS 8521, F-66125 Font Romeu, France

[5] ENSIC DCPR, INPL, UMR CNRS 7630, F-54001 Nancy, France

关键词: nanopatterning;    atomic force microscopy;    Langmuir/Blodgett/Kuhn assemblies;    DNA surfactants;   

DOI  :  10.1016/j.susc.2007.09.058

来源: Elsevier

【 摘 要 】

Our study aims at a better control and understanding of the transfer of a complex [DNA supercoiled plasmid - dodecyltrimethylammonium surfactant] layer from a liquid-vapour water interface onto a silicon surface without any additional cross-linker. The production of the complexed layer and its transfer from the aqueous subphase to the substrate is achieved with a Langmuir-Blodgett device. The substrate consists of a reconstructed boron doped silicon substrate with a nanometer-scale roughness. Using X-ray photoelectron spectroscopy and atomic force microscopy measurements, it is shown that the DNA complexes are stretched in a disorderly manner throughout a 2-4 nm high net-like structure. This architecture is composed of tilted cationic surfactant molecules bound electrostatically to DNA, which exhibits a characteristic network arrangement with a measured average fiber diameter of about 45 +/- 15 nm covering the entire surface. The mechanism of transfer of this layer onto the planar surface of the semi-conductor and the parameters of the process are analysed and illustrated by atomic force microscopy snapshots. The molecular layer exhibits the typical characteristics of a spinodal decomposition pattern or dewetting features. Plasmid molecules appear like long flattened fibers covering the surface, forming holes of various shapes and areas. The cluster-cluster aggregation of the complex structure gets very much denser on the substrate edge. The supercoiled DNA plasmids undergo conformational changes and a high degree of condensation and aggregation is observed. Perspectives and potential applications are considered. (C) 2007 Elsevier B.V. All rights reserved.

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