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A novel approach for selectively encapsulating Cy5 dye molecules viaDNA hybridization in cationic phosphorus dendrimers (G4+)/polystyrenesulfonate (PSS) microcapsules has been developed. The hybridization between Cy5 labeled single strand DNA (ssDNA) targets and complementary ssDNA probes was performed in the microcapsules. During hybridization, the ssDNA targets acted as ‘vehicles’ and Cy5 dye molecules as ‘cargos’, which led to the selective encapsulation of the Cy5 molecules inside the capsules. The approach may be applied for many small molecules, which are usually difficult to be encapsulated due to their diffusion properties in microcapsules. [ABSTRACT FROM AUTHOR]

Multilayer thin films of anionic gold nanoparticles (AuNPs) and cationic phosphorus dendrimers were deposited on 3-(diethoxymethyl-silyl)propylamine (3-APDMES)-coated substrates using layer-by-layer (LbL) assembly driven by electrostatic interactions. The growth of Au/dendrimer multilayers composed of AuNPswith diameters of ∼3 nm and ∼16 nm and dendrimer with ∼2 nm diameter was monitored by UV-vis spectroscopy. The relative amounts of AuNPsand dendrimers in the multilayer films were calculated using a quartz crystal microbalance. The Au-containing multilayers have two surface plasmon bands at ∼530 nm and ∼600 nm, where the latter exhibits a red shift upon increasing the areal density of AuNPs as well as increasing the layer number. The localized surface plasmon resonance (LSPR) band of the hybrid films can be tuned by adding NaCl to the dendrimer solution or by removing the organic matrix. These results demonstrate that the near-field coupling between the LSPR bands of neighboring Au layers is responsible for the controlled absorption behavior. Au mesoporous films after removing dendrimers show LSPR sensing properties for alcohols with different refractive indices in the range 1.33–1.41. A linear relationship was obtained between the LSPR peak wavelength and the refractive index of the surrounding medium. [ABSTRACT FROM AUTHOR]

Four series of phosphorus dendrimers (generations 1 and 4) having various types of amine terminal groups (pyrrolidine, morpholine, methyl piperazine, or phenyl piperazine) are synthesized. After protonation, the fourth generations of three of them are found water-soluble, and used for several biological experiments. First, the cytotoxicity of these polycationic dendrimers towards three cell strains (one healthy: HUVEC, and two cancerous: HEK 293 and HeLa) is assayed and found low. Second, their ability to interact with DNA is tested by electrophoresis: the dendrimer terminated by pyrrolidinium groups is found efficient to form dendriplexes. Finally, the polycationic dendrimers are used as transfection agents to deliver single- and double-stranded DNA into the three above-mentioned cell strains. Here also the dendrimer having pyrrolidinium groups is found the most efficient. [ABSTRACT FROM AUTHOR]

Dendrimers are hyperbranched nanosized and precisely defined molecules, attracting increasing attention each year due to their numerous properties in catalysis, materials science, and biology. This tutorial review concerns the use of dendrimers as catalysts and focuses more precisely on their properties as enantioselective catalysts. Emphasis is put on chiral phosphine complexes constituting the core or the end groups of various types of dendrimers. The effect of the location of the catalytic entities, the effect of the size (generation) and the nature of the dendritic skeleton on the enantiomeric excesses are discussed. [ABSTRACT FROM AUTHOR]

Organic nanodots based on the gathering of an exponentially increasing number of two-photon fluorophores on a dendritic platform of controlled size and symmetry represent a promising non-toxic alternative to quantum dots for (bio)imaging purposes. This modular route offers a number of advantages in terms of versatility but also raise a number of questions to be addressed. In particular, possible interactions between fluorophores, due to confinement effects, have to be taken into account. With this aim in mind we have investigated and compared the photophysical and two-photon absorption (TPA) properties of two series of organic nanodots of different geometries: spherical-like organic nanodots derived from a dendritic scaffold built from a cyclotriphosphazene core and dumbbell-like organic nanodots derived from a dendritic scaffold built from an elongated rod-like chromophore. The study provides evidence that the different topology and nature of the dendritic architecture lead to significant changes in photoluminescence characteristics as well as to subtle variations of the TPA efficiency. As a result, the dumbbell-like nanodots although less promising in terms of two-photon induced fluorescence (due to partial quenching of fluorescence efficiency) also demonstrate that improvement of the TPA efficiency can be achieved by playing on the nature and topology of the dendritic scaffold of the nanodots. [ABSTRACT FROM AUTHOR]

Generations 1 to 3 of dendrimers ended by water-soluble phosphines are synthesized and their ruthenium complexes are used as catalysts in aqueous media; a slightly positive dendritic effect on the regioselectivity is observed for hydration of alkynes and a large positive dendritic effect is observed in the biphasic (water/heptane) catalysed isomerisation of allylic alcohols to ketones where the products are easily isolated and the catalyst can be reused several times, even the first generation. [ABSTRACT FROM AUTHOR]