DNA adsorption at functionalized Si/buffer interfaces studied by x-ray reflectivity

C Douarche, R Cortes, C H de Villeneuve, S J Roser, A Braslau

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3 Citations (SciVal)


The adsorption of DNA on chemically homogeneous, functionalized, oxide-free single-crystal silicon surfaces is studied by x-ray reflectivity. The adsorption of monodisperse, 294 base-pair double-stranded DNA on a positively charged surface is detected through the deformation of the molecular monolayer of aminated alkyl-chain molecules covalently bonded to the surface. The adsorption of single-stranded DNA does not lead to the same deformation. A detailed quantitative characterization of the density profiles yield surface densities of the covalently grafted, molecular monolayers that are in excellent agreement with infrared spectroscopic measurements. The additional mass density that is measured following the adsorption of DNA corresponds either to the partial embedding of a densely-packed adsorbed layer or to a deeper penetration into the soft surface layer at a lower surface density of the adsorbed double-stranded DNA molecules. The adsorption is found to be irreversible under high added salt concentrations, suggesting a partial dehydration of the double-stranded DNA. (C) 2008 American Institute of Physics.
Original languageEnglish
Article number225108
Number of pages15
JournalJournal of Chemical Physics
Issue number22
Early online date12 Jun 2008
Publication statusPublished - 14 Jun 2008


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