Dresden 2014 – scientific programme

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O: Fachverband Oberflächenphysik

O 97: Organic/bio Molecules on Metal Surfaces IV

O 97.8: Talk

Friday, April 4, 2014, 12:15–12:30, TRE Phy

Fabrication of ssDNA/oligo(ethylene glycol) monolayers and complex nanostructures and brushes by promoted exchange reaction — M. Nuruzzaman Khan and •Michael Zharnikov — Angewandte Physikalische Chemie, Universität Heidelberg, Im Neuenheimer Feld 253, 69120 Heidelberg, Germany

Using a representative test system, we present here a versatile approach to prepare mixed monolayers of thiolate-bound single stranded DNA (ssDNA) and oligo(ethylene glycol) substituted alkanethiols (OEG-AT) in a broad range of compositions as well as ssDNA/OEG-AT patterns of desired shape imbedded into biorepulsive background. The procedure involves two steps. First, primary, well-defined OEG-AT monolayer on a solid support is exposed to electrons or UV light in either homogeneous or lithographic fashion. Second, the promoted (by the irradiation in the first step) exchange reaction between the damaged OEG-AT species in the film and ssDNA substituents in solution occurs, resulting in formation of ssDNA/OEG-AT monolayer or pattern. The composition of the mixed films or ssDNA/OEG-AT spots (lithography) can be precisely adjusted by electron or UV dose in almost entire composition range. The above procedure relies on commercially available compounds and is applicable to both thiolate substituted and disulfide type ssDNA, both symmetric and asymmetric. The fabricated OEG-AT/ssDNA templates and patterns can be, if necessary, extended into the z-dimension by surface-initiated enzymatic polymerization, which may result in formation of highly ordered ssDNA brushes and in sculpturing complex ssDNA brush patterns.