Optically induced linking of protein and nanoparticles to gold surfaces.

Attachment of molecules and proteins to surfaces is of great interest for the development of a large variety of applications. We present herein a novel approach to efficiently couple a molecule of choice to biological building blocks. We synthesized and employed a new derivative of 5-bromo-7-nitroindoline to attach nucleophilic molecules and proteins to gold surfaces by photochemical activation. The reaction can be seen as a photoactivated alternative to the activated ester type chemistries that are commonly used to attach proteins or molecules to surfaces. We characterize the reaction by UV-vis and NMR spectroscopy, and as test of principle experiment, we show that we can attach proteins to surfaces and demonstrate that we can functionalize gold nanoparticles by this optically induced cross-linking reaction.

Natural abundance solid-state 95Mo MAS NMR of MoS2 reveals precise 95Mo anisotropic parameters from its central and satellite transitions.

Precise values are reported for a quite large (95)Mo quadrupole coupling and an unusually large (95)Mo chemical shift anisotropy in MoS(2), values that have been retrieved by analysis of a well-resolved, highly complex 14.1 T (95)Mo MAS NMR spectrum displaying both the central and satellite transitions.

Self-assembly of (perfluoroalkyl)alkanes on a substrate surface from solutions in supercritical carbon dioxide.

Toroidal self-assembled structures of perfluorododecylnonadecane and perfluorotetradecyloctadecane have been deposited on mica and highly oriented pyrolytic graphite surfaces by exposure of the substrates to solutions of the (pefluoroalkyl)alkanes in supercritical carbon dioxide. Scanning force microscopy (SFM) images have displayed a high degree of regularity of these self-assembled nanoobjects regarding size, shape, and packing in a monolayer. Analysis of SFM images allowed us to estimate that each toroidal domain has an outer diameter of about 50 nm and consists of several thousands of molecules. We propose a simple model explaining the clustering of the molecules to objects with a finite size. The model based on the close-packing principles predicts formation of toroids, whose size is determined by the molecular geometry. Here, we consider the amphiphilic nature of the (perfluoroalkyl)alkane molecules in combination with incommensurable packing parameters of the alkyl- and the perfluoralkyl-segments to be a key factor for such a self-assembly.

Thioalkylated tetraethylene glycol: a new ligand for water soluble monolayer protected gold clusters.

Ligand-stabilised, water-soluble gold nanoparticles of two different size ranges (2-4 and 5-8 nm) are readily prepared using monohydroxy (1-mercaptoundec-11-yl) tetraethylene glycol as a novel capping agent. These nanoparticles are as stable as alkylthiol-capped monolayer protected clusters (MPCs) and do not aggregate from aqueous solution under a wide range of stringent conditions. It is expected that this new material will be useful for a number of bio-analytical applications.