Sticky nanoparticles: a platform for siRNA delivery by a bis(zinc(II) dipicolylamine)-functionalized, self-assembled nanoconjugate

Delivering the goods: Multifunctional, self-assembled, polymeric nanoparticles for the simultaneous delivery of small-molecule drugs and siRNA have been synthesized. The nanoparticles are composed of biodegradable hyaluronic acid, for tumor targeting and cellular delivery, and a high siRNA binding affinity is provided by a Zn(II)-dipicolylamine analogue as an artificial phosphate-binding receptor (see scheme).     

Direct correlation between work function of indium-tin-oxide electrodes and solar cell performance influenced by ultraviolet irradiation and air exposure

We report on reversible changes of the work function (WF) values of indium-tin-oxide (ITO) under prolonged ultraviolet (UV) and air exposure. The WF of ITO is reduced from 4.7 eV to 4.2 eV by photon absorption in ITO under UV illumination or an air mass 1.5 solar simulator (100 mW cm(-2)). Air or oxygen exposure is found to increase the WF of ITO (UV-exposed) to a value of 4.6 eV. These changes of ITO's WF lead to reversible variations of the performance of organic photovoltaic devices where ITO acts primarily as the electron collecting or hole collecting electrode. These variations can be reflected in the disappearance (or appearance) of an S-shaped kink in the J-V characteristics upon continuous UV or solar simulator illumination (or air exposure). This reversible phenomenon is ascribed to the adsorption and desorption of oxygen on the surface and grain boundaries of ITO. The use of surface modifiers to either decrease or increase the WF of ITO in organic photovoltaic devices with inverted and conventional geometries is also shown to be an effective route to stabilize the device performance under UV illumination.     

Light-matter interaction and polarization of single ZnO nanowire lasers

The optical properties of single zinc oxide (ZnO) nanolasers are investigated. ZnO nanowires with different diameters and lengths are prepared by chemical vapor transport. The diameter plays an important role in the stimulated emission process in nanowires. The spectral shift and spacing of Fabry-Pérot-type modes imply a strong light-matter interaction in the lasing nanowires, which is explained by the exciton-polariton model. The polarization of the electric field in the lasing nanowires is perpendicular to the long axis of the nanowire and parallel to the substrate plane. The coexistence of the transverse modes is distinguished by decomposing the peak shape and the degree of polarization. In addition to the transverse mode of the lasing with the polarization parallel to the substrate plane, the lasing mode with the polarization perpendicular to the substrate plane is observed.     

On-chip anticancer drug test of regular tumor spheroids formed in microwells by a distributive microchannel network

This paper proposes a new cytotoxicity assay in a microfluidic device with microwells and a distributive microfluidic channel network for the formation of cancer cell spheroids. The assay can generate rapid and uniform cell clusters in microwells and test in situ cytotoxicity of anticancer drugs including sequential drug treatments, long term culture of spheroids and cell viability assays. Inlet ports are connected to the microwells by a hydraulic resistance network. This uniform distribution of cell suspensions results in regular spheroid dimensions. Injected cancer cells were trapped in microwells, and aggregated into tumor spheroids within 3 days. A cytotoxicity test of the spheroids in microwells was subsequently processed in the same device without the extraction of cells. The in situ cytotoxicity assay of tumor spheroids in microwells was comparable with the MTT assay on hanging drop spheroids using a conventional 96-well plate. It was observed that the inhibition rate of the spheroids was less than that in the 2D culture dish and the effect on tumor spheroids was different depending on the anticancer drug. This device could provide a convenient in situ assay tool to assess the cytotoxicity of anticancer drugs on tumor spheroids, offering more information than the conventional 2D culture plate.     

Ultrafast rotary PCR system for multiple influenza viral RNA detection

We presented a novel platform for an ultrafast PCR system, called the Rotary PCR Genetic Analyzer, which incorporates a thermal block and resistive temperature detector (RTD) for thermal cycling control, a disposable PCR microchip, and a stepper motor. The influenza viral RNAs from H3N2, H5N1, and H1N1 were simultaneously identified with high sensitivity and speed.     

LC-MS/MS method for the quantification of myo- and chiro-inositol as the urinary biomarkers of insulin resistance in human urine

A simple LC‐MS/MS method has been developed and validated for the quantification of endogenous myo‐ and chiro‐inositol in human urine. myo‐ and chiro‐Inositol were completely resolved from other carbohydrates and there were no interference peaks in human urine. The correlation coefficient (n = 3) was greater than 0.9991 over the range 0.05–25.0 µg/mL with the weighted (1/C²) least square method. Precision (%RSD) and accuracy (%RE) were 0–10.0% and 0–6.0% for the intra‐day assay (n = 5) and 0–14.3% and 0–10.0% for the inter‐day assay (n = 5). myo‐ and chiro‐Inositol have been shown to be stable in human urine stored at room temperature and for three freeze–thaw cycles. Copyright © 2011 John Wiley & Sons, Ltd.     

Palladium-catalyzed arylation of α,β-unsaturated Weinreb amides

Palladium-catalyzed arylation of α,β-unsaturated Weinreb amides has been examined to obtain β-aryl-α,β-unsaturated Weinreb amides. The chelation between the palladium center of an alkylpalladium intermediate and Weinreb amide moiety facilitated both coordination and insertion steps.     

Indium-mediated regioselective mono-allylation of 1,5-dicarbonyl compounds and dehydrative cyclization to 2,3-dihydro-4H-pyran-4-ones and 3,4-dihydro-2H-[1,4]oxazines

An indium-mediated Barbier type mono-allylation of 1,5-dicarbonyl compounds and a subsequent acid-catalyzed dehydrative cyclization afforded 2,3-dihydro-4H-pyran-4-ones and 3,4-dihydro-2H-[1,4]oxazines.