Diboron and Triboron Compounds Based on Linear and Star-Shaped Conjugated Ligands with 8-Hydroxyquinolate Functionality: Impact of Intermolecular Interaction and Boron Coordination on Luminescence

New 8-R-quinoline functionalized linear and star-shaped conjugated molecules have been synthesized using Suzuki−Miyaura coupling methods (R = MeO, L1−L5; R = CH3OCH2O, L1‘−L5‘). When treated with HCl, L1‘−L5‘ are converted readily to the corresponding 8-hydroxyquinoline compounds L(OH)1−L(OH)5 which react readily with BPh3 in refluxing THF to produce the corresponding polyboron chelate compounds B1−B5 in good yields. L1−L5 and B1−B5 display similar thermal stability with Td at ∼300 °C. Experimental and molecular orbital calculation results showed that the chelation by boron stabilizes the LUMO level of the ligand and narrows the HOMO−LUMO gap, resulting in the blue emission of the ligands and the green or orange emission of the boron compounds. Crystal structures of L1, L3, and L5 showed that these molecules have layered arrangements in the solid state with significant intermolecular π−π interactions. The linear diboron B5 displays concentration and temperature-dependent emission in solution, attributable to intermolecular interactions. The properties of a monoboron compound BPh2(5-Ph-8-MeO-q) (B0) and its corresponding free ligand L0 were investigated and compared to the closely related diboron compound B1 and the ligand L1, which revealed that the increase of the number of chromophores linked by an aromatic group has a significant impact on thermal stability and the HOMO and LUMO energy levels

Single-Cell Quantification of Cytosine Modifications by Hyperspectral Dark-Field Imaging

Epigenetic modifications on DNA, especially on cytosine, play a critical role in regulating gene expression and genome stability. It is known that the levels of different cytosine derivatives are highly dynamic and are regulated by a variety of factors that act on the chromatin. Here we report an optical methodology based on hyperspectral dark-field imaging (HSDFI) using plasmonic nanoprobes to quantify the recently identified cytosine modifications on DNA in single cells. Gold (Au) and silver (Ag) nanoparticles (NPs) functionalized with specific antibodies were used as contrast-generating agents due to their strong local surface plasmon resonance (LSPR) properties. With this powerful platform we have revealed the spatial distribution and quantity of 5-carboxylcytosine (5caC) at the different stages in cell cycle and demonstrated that 5caC was a stably inherited epigenetic mark. We have also shown that the regional density of 5caC on a single chromosome can be mapped due to the spectral sensitivity of the nanoprobes in relation to the interparticle distance. Notably, HSDFI enables an efficient removal of the scattering noises from nonspecifically aggregated nanoprobes, to improve accuracy in the quantification of different cytosine modifications in single cells. Further, by separating the LSPR fingerprints of AuNPs and AgNPs, multiplex detection of two cytosine modifications was also performed. Our results demonstrate HSDFI as a versatile platform for spatial and spectroscopic characterization of plasmonic nanoprobe-labeled nuclear targets at the single-cell level for quantitative epigenetic screening

Growth curves of control and TaClo treated HEK 293 cells.

Statistically significant difference was observed in day 6.</p

Electrical Switching and Phase Transformation in Silver Selenide Nanowires

We report for the first time the electrical transport in solid-state electrolyte nanowires. Single nanowire transport and in situ transmission electron microscopy studies show that Ag2Se nanowires can be high conducting orthorhombic β-Ag2Se or low conducting cubic α-Ag2Se. It is also the first time that α-Ag2Se is found to be stable at room temperature. A threshold switching phenomenon exists in the low conducting α-Ag2Se with an on−off ratio up to 7 order magnitude. These results provide useful new information for exploring solid-state electrolyte nanowires as resistive switching memory devices

Anisotropy of Chemical Transformation from In₂Se₃ to CuInSe₂ Nanowires through Solid State Reaction

Anisotropy of Chemical Transformation from In2Se3 to CuInSe2 Nanowires through Solid State Reactio

qRT-PCR primers used in this study.

<p>All primers listed are from 5’ to 3’.</p

Anchorage independent growth of control and TaClo treated HEK 293 cells.

<p>After TaClo treatment, the fluorescence intensities increased around 1.5 fold.</p

Analysis of cell migration by <i>in vitro</i> scratch assay.

<p>Images were acquired at 0 and 18 h. Scale bar, 400 μm.</p

Low-Temperature Self-Catalytic Growth of Tin Oxide Nanocones over Large Areas

Nanoscale texturing has been studied for various applications, but most of the methods used to make these nanostructures are expensive and not easily scalable. Some of these methods require etching steps or high-temperature processes, which limit the processes to certain materials, such as silicon. In this study, we report a non-etching nanoscale texturing technique that allows for controlled oxidation to create tin oxide nanocones over large areas. Similar results are obtained on different substrates, such as silicon, aluminum foil, quartz, and polyimide film, and this method can be employed at temperatures as low as 220 °C in ambient pressure. This simple and scalable nanotexturing process improves the anti-reflection effect in photovoltaic devices. The light absorption of a polycrystalline silicon substrate, a widely used photovoltaic material, is increased by 30% over the wavelength range of 400–850 nm after fabricating nanocones on the surface