Unique electrochemiluminescence behavior of Ru(bpy)(3)(2+) in a gold/Nafion/Ru(bpy)(3)(2+) composite

The unique electrochemiluminescence (ECL) behavior of tris(bipyridine) ruthenium(II) (Ru(bpy)(3)(2+) immobilized in a gold/Nafion/Ru(bpy)(3)(2+) composite material was investigated. In this composite, the Ru(bpy)(3)(2+) ECL was found mainly occurred at 0-0.4 V during the cathodic scan process and the ECL peak was at about 0.1 V, which was quite different to the reported Ru(bpy)(3)(2+) ECL. Similar to the generally observed Ru(bpy)(3)(2+) ECL, the present ECL also could be enhanced by tri-n-propylarnine (TPA). It is also unique that in the presence of TPA, another ECL peak at about 0.38 V occurred.

Effect of Freeze-Thawing on Lipid Bilayer-Protected Gold Nanoparticles

In this study, varieties of lipid bilayer-protected gold nanoparticles (AuNPs) were synthesized through a simple wet chemical method, and then the effect of freeze-thawing on the as-prepared AuNPs was investigated. The freeze-thawing process induced fusion or fission of lipid bilayers tethered on the AuNPs. The UV-vis spectra and transmission electron microscopy experiments revealed that the disruption of lipid bilayer structures on the nanoparticles led to the fusion or aggregation of AuNPs.

Simple Electrochemical Route to Nanofiber Junctions and Dendrites of Conducting Polymer

We first report a simple and rapid electrochemical approach to synthesize novel nanofiber junctions and dendrites of conducting poly(o-phenylenediamine) without any surfactant or template. Through controlling some parameters such as the time and potential of electrodeposition and concentration of the reactant, nanofiber junctions and dendrites of conducting polymer can be easily obtained on the solid surface.

Adsorption of 4,4 '-thiobisbenzenethiol on silver surfaces: surface-enhanced Raman scattering study

Adsorption of 4,4'-thiobisbenzenethiol (4,4'-TBBT) on a colloidal silver surface and a roughened silver electrode surface was investigated by means of surface-enhanced Raman scattering (SERS) for the first time, which indicates that 4,4'-TBBT is chemisorbed on the colloidal silver surface as dithiolates by losing two H-atoms of the S-H bond, while as monothiolates on the roughened silver electrode. The different orientations of the molecules on both silver surfaces indicate the different adsorption behaviors of 4,4'-TBBT in the two systems.

Facile fabrication of large area of aggregated gold nanorods film for efficient surface-enhanced Raman scattering

An effective and facile method for fabrication of large area of aggregated gold nanorods (AuNRs) film was proposed by self-assembly of AuNRs at a toluene/water interface for the first time. It was found that large area of aggregated AuNRs film could be formed at the interface of toluene and water due to the interfacial tension between the two phases. The obtained large area of aggregated AuNRs film exhibits strong surface-enhanced Raman scattering (SERS) activity with 4-aminothiophenol (4-ATP) and 2-aminothiophenol (2-ATP) as the probe molecules based on the strong electromagnetic coupling effect between the very adjacent AuNRs.

Environmentally friendly synthesis of highly monodisperse biocompatible gold nanoparticles with urchin-like shape

We report a facile and environmentally friendly strategy for high-yield synthesis of highly monodisperse gold nanoparticles with urchin-like shape. A simple protein, gelatin, was first used for the control over shape and orientation of the gold nanoparticles. These nanoparticles, ready to use for biological systems, are promising in the optical imaging-based disease diagnostics and therapy because of their tunable surface plasmon resonance (SPR) and excellent surface-enhanced Raman scattering (SERS) activity.

A topography/chemical composition gradient polystyrene surface: Toward the investigation of the relationship between surface wettability and surface structure and chemical composition

In this paper, we have prepared of a topography/chemical composition gradient polystyrene (PS) surface, i.e., an orthogonal gradient surface, to investigate the relationship between surface wettability and surface structure and chemical composition. The prepared surface shows a one-dimensional gradient in wettability in the x, y, and diagonal directions, including hydrophobic to hydrophilic, superhydrophobic to hydrophobic, superhydrophobic to superhydrophilic gradients, and so forth.

The electrochemical behavior of a system with a limited number of molecules

In this paper, based on Einstein relationship between diffusion and random walk, the electrochemical behavior of a system with a limited number of molecules was simulated and explored theoretically. The transition of the current vs time responses from discrete to continuous was clearly obtained as the number of redox molecules increased from 10 to 10(6).

Metallic Cation Induced One-Dimensional Assembly of Poly(acrylic acid)-1-Dodecanethiol-Stabilized Gold Nanoparticles

In this work, we report a simple approach for controllable synthesis of one-dimensional (ID) gold nanoparticle (AuNP) assemblies in solution. In the presence of divalent metallic ions, poly(acrylic acid)-1-dodecanethiol-stabilized AuNPs (PAA-DDT@AuNPs) are found to form I D assemblies in aqueous solution by an ion-templated chelation process; this causes an easily measurable change in the absorption spectrum of the particles. The assemblies are very stable and remain suspended in solution for more than one month without significant aggregation.

Functional gold nanoparticle-peptide complexes as cell-targeting agents

In this paper, we report a novel approach using peptide CALNN and its derivative CALNNGGRRRRRRRR (CALNNR(8)) to functionalize gold nanoparticles for intracellular component targeting. The translocation is effected by the nanoparticle diameter and CALNNR8 surface coverage. The intracellular distributions of the complexes are change from the cellular nucleus to the endoplasmic reticulum by increasing the density of CALNNR8 at a constant nanoparticle diameter. Additionally, increasing the nanoparticle diameter at a constant density of CALNNR8 leads to less cellular internalization.

Facile preparation of macroscopic soft colloidal crystals with fiber symmetry

A facile, efficient way to fabricate macroscopic soft colloidal crystals with fiber symmetry by drying a latex dispersion in a tube is presented. A transparent, stable colloidal crystal was obtained from a 25 wt % latex dispersion by complete water evaporation for 4 days. The centimeter-long sample was investigated by means of synchrotron small-angle X-ray diffraction (SAXD). Analysis of a large number of distinct Bragg peaks reveals that uniaxially oriented colloidal crystals with face-centered cubic lattice structure were formed.

The modification of self-assembled monolayer on indium tin oxide as cathode in inverted bottom-emitting organic light-emitting diodes

Self-assembled monolayers (SAMs) of a series of p-substituted benzoyl chlorides were formed on indium tin oxide as the cathode for the fabrication of inverted bottom-emitting organic light-emitting diodes (IBOLEDs). The studies on the efficiency of electron injection and device performances showed that the direct tunneling of electron and the formation of dipole associated with the monolayer-forming molecule lead to significant enhancement in electron injection. Consequently, the device efficiency is greatly improved.

Formation of reversible shell cross-linked micelles from the biodegradable amphiphilic diblock copolymer poly(L-cysteine)-block-poly(L-lactide)

A novel biodegradable diblock copolymer, poly(L-cysteine)-b-Poly(L-lactide) (PLC-b-PLLA), was synthesized by ring-opening polymerization (ROP) of N-carboxyanhydride of beta-benzyloxycarbonyl-L-Cysteine (ZLC-NCA) with amino-terminated Poly(L-lactide) (NH2-PLLA) as a macroinitiator in a convenient way. The diblock copolymer and its precursor were characterized by H-1 NMR, Fourier transform infrared (FT-IR), gel permeation chromatography (GPC), and X-ray photoelectron spectroscopy (XPS) measurements. The length of each block polymer could be tailored by molecular design and the ratios of feeding monomers.

Weak epitaxy growth of metal-free phthalocyanine on p-sexiphenyl monolayer and double-layer films

Weak epitaxy growth (WEG) can afford high-mobility thin films of disk-like organic semiconductor of which mobility is up to the level of the corresponding single crystals. We investigated the WEG behavior and mechanism of planar phthalocyanine in the model system of metal-free phthalocyanine (H2Pc) grown on p-sexiphenyl (p-6P) ultrathin films (monolayers and double layers). Highly oriented H2Pc films with molecules standing up exhibited two kinds of different in-plane orientations, i.e., three sets of in-plane orientations and only one set of in-plane orientation, on p-6P monolayer and double-layer films, respectively.

Ion-Responsive Behavior of Ionic-Liquid Surfactant Aggregates with Applications in Controlled Release and Emulsification

We propose a simple but efficient, rapid, and quantitative ion-responsive micelle system based on counter-anion exchange of a surfactant with an imidazolium unit. The ion-exchange reaction results in the amphiphilic-to-hydrophobic transition of the imidazolium salt, leading to the destruction of the micelles, which has been successfully applied to control led release and emulsification.