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Chemiluminescence was used as an excitation light source to construct a universal photoelectrochemical platform based on Mn2+-doped NaYF4:Yb/Er upconversion nanoparticles, which greatly improves the electrochemiluminescence intensity and offers more stable cathodic signals compared to pure NaYF4:Yb/Er NPs. Here, we report for the first time the ECL behaviors of Mn2+-doped NaYF4:Yb/Er NPs, which were synthesized via a facile strategy. Mn2+ doping resulted in a 4-fold ECL intensity enhancement of NaYF4:Yb/Er. The characteristics of Mn2+-doped NaYF4:Yb/Er nanocomposites were obtained using transmission electron microscopy (TEM), energy dispersive X-ray spectrometer (EDS), and fluorescence spectra. After all the results had indicated that NaYF4:Yb/Er upconversion nanoparticles were successfully doped with Mn[sup 2+], the electrochemiluminescence platform was built. The as-prepared NaYF4:Yb/Er NPs were rendered water-soluble and then employed as ECL emitters for carcinoembryonic antigen (CEA) determination. The results indicated that the modified electrode can be used to determine CEA without interference from non-specific proteins, with a low detection limit of 5.2 pg mL-1. The biosensor can also be used for quantification of the CEA concentration in real samples. [ABSTRACT FROM AUTHOR]

This study describes a new method to prepare monodisperse polystyrene (PS) colloidal nanoparticles with controlled size ranging from 60 nm to 140 nm by the direct polymerization of styrene and divinylbenzene inside the bilayers of the polydisperse hyperbranched polymer vesicles. [ABSTRACT FROM AUTHOR]

We report the development of a microfabricated electrophoretic device for assembling high-density arrays of antibody-conjugated microbeads for chip-based protein detection. The device consists of a flow cell formed between a gold-coated silicon chip with an array of microwells etched in a silicon dioxide film and a glass coverslip with a series of thin gold counter electrode lines. We have demonstrated that 0.4 and 1 μm beads conjugated with antibodies can be rapidly assembled into the microwells by applying a pulsed electric field across the chamber. By assembling step-wise a mixture of fluorescently labeled antibody-conjugated microbeads, we incorporated both spatial and fluorescence encoding strategies to demonstrate significant multiplexing capabilities. We have shown that these antibody-conjugated microbead arrays can be used to perform on-chip sandwich immunoassays to detect test antigens at concentrations as low as 40 pM (6 ng/mL). A finite element model was also developed to examine the electric field distribution within the device for different counter electrode configurations over a range of line pitches and chamber heights. This device will be useful for assembling high-density, encoded antibody arrays for multiplexed detection of proteins and other types of protein-conjugated microbeads for applications such as the analysis of protein-protein interactions. [ABSTRACT FROM AUTHOR]

We report a method for rapid, electric field directed assembly of high-density protein-conjugated microbead arrays. Photolithography is used to fabricate an array of micron to sub-micron-scale wells in an epoxy-based photoresist on a silicon wafer coated with a thin gold film, which serves as the primary electrode. A thin gasket is used to form a microfluidic chamber between the wafer and a glass coverslip coated with indium-tin oxide, which serves as the counter electrode. Streptavidin-conjugated microbeads suspended in a low conductance buffer are introduced into the chamber and directed into the wells viaelectrophoresis by applying a series of low voltage electrical pulses across the electrodes. Hundreds of millions of microbeads can be permanently assembled on these arrays in as little as 30 seconds and the process can be monitored in real time using epifluorescence microscopy. The binding of the microbeads to the gold film is robust and occurs through electrochemically induced gold-protein interactions, which allows excess beads to be washed away or recycled. The well and bead sizes are chosen such that only one bead can be captured in each well. Filling efficiencies greater than 99.9% have been demonstrated across wafer-scale arrays with densities as high as 69 million beads per cm2. Potential applications for this technology include the assembly of DNA arrays for high-throughput genome sequencing and antibody arrays for proteomic studies. Following array assembly, this device may also be used to enhance the concentration-dependent processes of various assays through the accelerated transport of molecules using electric fields. [ABSTRACT FROM AUTHOR]

Complexes [PF6⊂(Ag3(titmb)2](PF6)2 (8) and {SbF6⊂[Ag3(titmb)2](SbF6)2}·H2O·1.5 CH3OH (9) are obtained by reaction of titmb and Ag+ salts with different anions (PF6− and SbF6−), and crystal structures reveal that they are both M3L2 cage complexes with short Ag⋯F interactions between the silver atoms and the fluorine atoms of the anions. In complex 8, a novel cage dimer is formed by weak Ag⋯F contacts; an unique cage tetramer formed via Ag⋯π interactions (Ag⋯η5-imidazole) between dimers and an infinite 1D cage chain is presented. However, each of the external non-disordered SbF6− anions connect with six cage 9s via Ag⋯F contacts, and each cage 9 in turn connects with three SbF6− anions to form a 2D network cage layer; and the layers are connected by π–π interactions to form a 3D network. The anion-exchange reactions of four Ag3L2 type complexes ([BF4⊂(Ag3(titmb)2](BF4)2 (6), [ClO4⊂(Ag3(titmb)2](ClO4)2 (7b), [PF6⊂(Ag3(titmb)2](PF6)2 (8) and [SbF6⊂(Ag3(titmb)2](SbF6)2·1.5CH3OH (9)) with tetrahedral and octahedral anions (ClO4−, BF4−, PF6− and SbF6−) are also reported. The anion-exchange experiments demonstrate that the anion selective order is SbF6− > PF6− > BF4−, ClO4−, and this anion receptor is preferred to trap octahedral and tetrahedral anions rather than linear or triangle anions; SbF6− is the biggest and most preferable one, so far. The dimensions of cage complexes with or without internal anions, anion-exchange reactions, cage assembly and anion inclusions, silver(i) coordination environments, Ag–F and Ag–π interactions of Ag3L2 complexes 1–9 are discussed. [ABSTRACT FROM AUTHOR]

Complexes [PF6⊂(Ag3(titmb)2](PF6)2 (8) and {SbF6⊂[Ag3(titmb)2](SbF6)2}·H2O·1.5 CH3OH (9) are obtained by reaction of titmb and Ag+ salts with different anions (PF6− and SbF6−), and crystal structures reveal that they are both M3L2 cage complexes with short Ag⋯F interactions between the silver atoms and the fluorine atoms of the anions. In complex 8, a novel cage dimer is formed by weak Ag⋯F contacts; an unique cage tetramer formed via Ag⋯π interactions (Ag⋯η5-imidazole) between dimers and an infinite 1D cage chain is presented. However, each of the external non-disordered SbF6− anions connect with six cage 9s via Ag⋯F contacts, and each cage 9 in turn connects with three SbF6− anions to form a 2D network cage layer; and the layers are connected by π–π interactions to form a 3D network. The anion-exchange reactions of four Ag3L2 type complexes ([BF4⊂(Ag3(titmb)2](BF4)2 (6), [ClO4⊂(Ag3(titmb)2](ClO4)2 (7b), [PF6⊂(Ag3(titmb)2](PF6)2 (8) and [SbF6⊂(Ag3(titmb)2](SbF6)2·1.5CH3OH (9)) with tetrahedral and octahedral anions (ClO4−, BF4−, PF6− and SbF6−) are also reported. The anion-exchange experiments demonstrate that the anion selective order is SbF6− > PF6− > BF4−, ClO4−, and this anion receptor is preferred to trap octahedral and tetrahedral anions rather than linear or triangle anions; SbF6− is the biggest and most preferable one, so far. The dimensions of cage complexes with or without internal anions, anion-exchange reactions, cage assembly and anion inclusions, silver(i) coordination environments, Ag–F and Ag–π interactions of Ag3L2 complexes 1–9 are discussed. [ABSTRACT FROM AUTHOR]

CdS hollow spheres of about 25 nm average diameter and about 5 nm shell thickness can be easily synthesized in an aqueous solution of polyglycol. It was found that the polyglycol had a significant influence on the formation of the CdS hollow spheres, because when the experiments were carried out in the absence of polyglycol, only solid particles were formed. High-resolution transmission electron microscopy (HRTEM) shows the shell of the CdS hollow spheres is formed by a layer of primary CdS particles. The Brunauer–Emmett–Teller (BET) surface area of the CdS hollow spheres calculated from the N2 adsorption isotherm is 98.2 m2 g−1, which is much larger than the value of about 49.8 m2 g−1 calculated for the surface area of solid spheres. Compared with previous reports, the prepared hollow spheres have a small diameter, a large surface area and a thin shell. The photoluminescence (PL) spectrum of the CdS hollow spheres at 220 nm excitation shows two sharp emission peaks centered ∼493 nm and ∼530 nm which may be ascribed to the near band edge emission arising from the recombination of excitons and/or shallow trapped electron–hole pairs. Electrogenerated chemiluminescence (ECL) from the CdS hollow spheres and its first application to sensing H2O2 were studied. The H2O2 sensor based on ECL from the CdS hollow spheres had much better responses than those from CdS solid nanoparticles and had good stability. [ABSTRACT FROM AUTHOR]

A siliceous mesocellular foam-immobilized Ru–TsDPEN complex exhibited excellent catalytic reactivity, enantioselectivity and reusability in the asymmetric transfer hydrogenation of an imine and ketones. [ABSTRACT FROM AUTHOR]