H-aggregates of the cyanine dye Cy5 are formed during covalent linkage to the cationic macromolecule Poly(allylamine) (PAH). The nonfluorescent H-aggregates strongly restrict the usage of the dye for analytical purposes and prevent a quantitative determination of the labeled macromolecules. The behavior of the H-aggregates has been studied by investigation of the absorption and fluorescence spectra of the dye polymer in dependence on solvent, label degree and additional sulfonate groups. H-aggregate formation is caused by an inhomogeneous distribution of the Cy5 molecules on the polymer chain. The H-aggregates can be destroyed by conformational changes of the PAH induced by interactions with polyanions or in organic solvents. It has been found that the polymer labeling process in high content of organic solvents can prevent the formation of H-aggregates. The results offer a better understanding and improvement of the use of the Cy5 dye for labeling purposes in fluorescence detection of macromolecules.

Microscopic colloidal particles allow a precise regulation of chemical reactions in time and place. A controlled assembly of multiple layers of intact lipid vesicles on a solid support provided by layer‐by‐layer particles functionalized by a covalent attachment of DNA oligonucleotides is reported (see image). Lipophilic complementary oligonucleotides are incorporated into lipid vesicles. Fusion of liposomes and release can be triggered.

Specific modification of properties such as porosity and pore size of engineered wood‐based source material enables the custom design of porous wood‐derived SiC that is produced by carbothermal reduction between the carbonized wood‐based material and an infiltrated silica sol. In contrast to bulk wood, the anisotropic shrinkage of the source material is less distinctive and can be controlled. Furthermore, the obtained structural properties of the material are isotropic. Material processing and properties of the wood‐derived ceramic material are described in this paper.

A straightforward synthesis of 2Ј-functionalized uridines was developed based on a Cu-catalyzed cycloaddition of 2Ј-azido-2Ј-deoxyuridine and functionalized alkynes. The functions comprise biochemically important groups such as lipids, a fluorescent marker (Cy5 analogue), pentaacetylglucose, lysine and biotin, and are linked to the 2Ј-position of uridine

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Various new nucleosides bearing one or two lipophilic groups at the 2′‐position have been synthesized. The lipophilic substituents were attached to a 2′‐hydroxy, 2′‐amino, or 2′‐thio function. These lipophilic nucleosides anchor in large unilamellar POPC vesicles serving as phospholipid membrane models. The insertion of these molecules into the membranes was investigated by NMR techniques. For comparison, nucleosides with two or three lipophilic groups at the 2′‐, 3′‐, or 5′‐positions have also been studied.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

Keywords: Nucleosides / Amphiphiles / Lipophilicity / Membrane anchoring / Synthesis Nucleosides were synthesized bearing one or two lipophilic groups at the 5Ј-position. The lipophilic substituents can be fixed at a 5Ј-amino group or at the 5Ј-phosphate moiety. Selected examples of these lipophilic nucleosides are shown by

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