A high-performance hydrogen gas sensor using ultrathin polypyrrole-coated CNT nanohybrids.

A novel strategy for designing ultrathin polypyrrole skin-coated carbon nanotube (CNT) nanohybrids is demonstrated by vapor deposition polymerization (VDP). The ultrathin skin technology provides a stable immobilization of the mono-disperse Pd nanoparticles (NPs) on the CP-CNT nanohybrid surface, leading to a high-performance hydrogen gas sensor at room temperature.

PRIMA-1 increases cisplatin sensitivity in chemoresistant ovarian cancer cells with p53 mutation: a requirement for Akt down-regulation.

Background: Since ovarian cancer is associated with high frequency of p53 mutation, the availability of p53 reactivation and induction of massive apoptosis (PRIMA-1) offers a possible new therapeutic strategy for overcoming this devastating disease. Although Akt activation is believed to be a determinant in chemoresistance in ovarian cancer, whether Akt plays a role in regulating the effectiveness of PRIMA-1 in sensitizing chemoresistant ovarian cancer cells with p53 mutation to cisplatin (CDDP), remains to be determined.

Methods: In the present studies, we examined the influence of Akt down-regulation following dominant-negative (DN-Akt) expression on the ability of PRIMA-1 (0-10 μM) to facilitate CDDP (0-10 μM)-induced apoptosis in p53-mutated chemoresistant ovarian cancer cells (A2780cp).

Fabrication of graphene sheets intercalated with manganese oxide/carbon nanofibers: toward high-capacity energy storage.

Herein, 3D nanohybrid architectures consisting of MnO(x) nanocrystals, carbon nanofibers (CNFs), and graphene sheets are fabricated. MnO(x) -decorated CNFs (MCNFs) with diameters of about 50 nm are readily obtained via single-nozzle co-electrospinning, followed by heat treatment. The MCNFs are then intercalated between graphene sheets, yielding the ternary nanohybrid MCNF/reduced graphene oxide (RGO).

Role of reactive oxygen species in Escherichia coli inactivation by cupric ion.

This study demonstrated Escherichia coli inactivation by cupric ion (Cu[II]), focusing on intracellular generation and consumption of reactive oxygen species (ROS) including superoxide and hydroxyl radials. In the presence of Cu(II), intracellular superoxide levels of E. coli decreased in a concentration-dependent manner, indicating that superoxide radical was used to reduce Cu(II) to Cu(I) in cells.

Designed architecture of multiscale porous TiO2 nanofibers for dye-sensitized solar cells photoanode.

Multiscale porous (MSP) TiO(2) nanofibers (NFs) were fabricated using a simple electrospinning and etching process with TiO(2)/SiO(2) composite NFs for high-efficiency dye-sensitized solar cells (DSSCs). TiO(2) NFs with different pore sizes (small, large, and multiscale) were prepared using SiO(2) nanoparticles of various sizes. The surface area of the MSP TiO(2) NFs was nine times higher than that of pristine TiO(2) NFs, providing sufficient dye adsorption for light harvesting as well as efficient paths for electrolyte contact.

Fluorescent polymer nanoparticle for selective sensing of intracellular hydrogen peroxide.

Fluorescent boronate-modified polyacrylonitrile (BPAN) nanoparticles of 50 nm diameter were fabricated for use as a selective H(2)O(2) sensor. The fluorescence intensity changed and an emission peak shifted when BPAN nanoparticles selectively interacted with H(2)O(2), relative to other reactive oxygen species (ROS). The BPAN nanoparticles undergo photoinduced electron transfer (PET) between a Schiff base moiety and boronate, which enhances the fluorescence and makes the nanoparticles suitable for selective ROS recognition.

Selective deposition of Pt onto supported metal clusters for fuel cell electrocatalysts.

We report a new method for deposition of Pt on a metal core to develop real electrocatalysts with significantly reduced amounts of expensive Pt as well as enhanced activity for oxygen reduction reaction. Ru and Pd have different crystal structures and modify the electronic structure of Pt to a different extent (shifts in d-band center). They were chosen as core materials to examine whether hydroquinone dissolved in ethanol can be used to deposit additional Pt atoms onto preformed core nanoparticles, and whether the modified d-character of Pt on different host metals can result in the enhanced ORR activity.

Dimension-controlled synthesis of CdS nanocrystals: from 0D quantum dots to 2D nanoplates.

The dimension-controlled synthesis of CdS nanocrystals in the strong quantum confinement regime is reported. Zero-, one-, and two-dimensional CdS nanocrystals are selectively synthesized via low-temperature reactions using alkylamines as surface-capping ligands. The shape of the nanocrystals is controlled systematically by using different amines and reaction conditions.

Synthesis of TiO2 nanorod-decorated graphene sheets and their highly efficient photocatalytic activities under visible-light irradiation.

The titanium dioxide (TiO(2)) nanorod-decorated graphene sheets photocatalysts with different TiO(2) nanorods population have been synthesized by a simple non-hydrolytic sol-gel approach. Electron microscopy and X-ray diffraction analysis indicated that the TiO(2) nanorods are well-dispersed and successfully anchored on the graphene sheet surface through the formation of covalent bonds between Ti and C atoms. The photocatalytic activities are evaluated in terms of the efficiencies of photodecomposition and adsorption of methylene blue (MB) in aqueous solution under visible-light irradiation.

Pitch reduction lithography by pressure-assisted selective wetting and thermal reflow.

We report on a new pitch reduction lithographic technique by utilizing pressure-assisted selective wetting and thermal reflow. The primary line-and-space pattern of low molecular weight polystyrene (PS) (Mw=17,300) was formed by solvent-assisted capillary force lithography (CFL), on which a diluted photoresist (PR) solution was selectively filled into the spaces by the application of a slight pressure (200 g cm(-2)). Subsequent removal of the PS pattern by toluene and ashing process led to a line pattern with approximately 50% pitch reduction.

Efficient intracellular delivery of camptothecin by silica/titania hollow nanoparticles.

Silica/titania hollow nanoparticles (HNPs) with 50 nm were fabricated by using the dissolution and redeposition method and modified with anti-[human epidermal growth factor receptor 2] monoclonal antibody (herceptin), and their application as camptothecin (CPT) delivery agents to human breast cancer SK-BR-3 cells was investigated. Although the diameter of herceptin-modified HNPs (HER-HNP) is smaller than that of other reported mesoporous silica nanoparticles, the extensive hollow cavity of HNPs (ca. 30 nm) allowed the loading of a large amount of CPT.

The Role of Confined Water in Ionic Liquid Electrolytes for Dye-Sensitized Solar Cells.

Ionic liquids (ILs) provide an attractive medium for various chemical and redox reactions, where they are generally regarded as hydrophobic. However, Seddon et al. discovered that 4-10 wt % water absorbs into ILs that contain bulky anions, and Cammarata et al.

Stabilization of RNT-1 protein, runt-related transcription factor (RUNX) protein homolog of Caenorhabditis elegans, by oxidative stress through mitogen-activated protein kinase pathway.

RUNX proteins are evolutionarily conserved transcription factors known to be involved in various developmental processes. Here we report a new role for a RUNX protein: a role in stress response. We show that RNT-1, the Caenorhabditis elegans RUNX homolog, is constantly produced and degraded by the ubiquitination-proteasome pathway in the intestine of the nematode.

n-Type nanostructured thermoelectric materials prepared from chemically synthesized ultrathin Bi2Te3 nanoplates.

We herein report on the large-scale synthesis of ultrathin Bi(2)Te(3) nanoplates and subsequent spark plasma sintering to fabricate n-type nanostructured bulk thermoelectric materials. Bi(2)Te(3) nanoplates were synthesized by the reaction between bismuth thiolate and tri-n-octylphosphine telluride in oleylamine. The thickness of the nanoplates was ~1 nm, which corresponds to a single layer in Bi(2)Te(3) crystals.

Fabrication of ultrafine metal-oxide-decorated carbon nanofibers for DMMP sensor application.

Ultrafine metal-oxide-decorated hybrid carbon nanofibers (CNFs) were fabricated by a single-nozzle co-electrospinning process using a phase-separated mixed polymer composite solution and heat treatment. To decorate metal oxides on the CNF surface, core (PAN) and shell (PVP) structured nanofibers (NFs) were fabricated as starting materials. The core-shell NF structure was prepared by single-nozzle co-electrospinning because of the incompatibility of the two polymers.

Fluorescent europium-modified polymer nanoparticles for rapid and sensitive anthrax sensors.

Novel fluorescent polyacrylonitrile nanoparticles were synthesized by microemulsion polymerization and Schiff base modification. By further modification with europium, the polyacrylonitrile nanoparticles could be used as a highly sensitive and rapid sensor for Bacillus anthracis spore detection in aqueous solution. The europium-modified polyacrylonitrile nanoparticles were readily combined with dipicolinic acid as a unique biomarker of B.

Shape-dependent cytotoxicity of polyaniline nanomaterials in human fibroblast cells.

The toxicity of polyaniline (PANI) nanomaterials with four different aspect ratios on human lung fibroblast cells was investigated by cell viability assay, cytotoxicity assay, apoptosis/necrosis measurement, and reactive oxygen species production. The toxicity increased with decreasing aspect ratio of PANI nanomaterials. In contrast, the highest aspect ratio PANI nanomaterials showed similar results with bulk PANI materials.

Fabrication of polymer nanotubes containing nanoparticles and inside functionalization.

A polypyrrole nanotube containing nanoparticles is prepared by a dual template approach, and the inside of the nanotube is selectively functionalized with carboxyl and amine groups.

Influence of attached bacteria and biofilm on double-layer capacitance during biofilm monitoring by electrochemical impedance spectroscopy.

Development of an effective strategy for biofilm control in water-related system has become a matter of significant concern nowadays. Electrochemical monitoring, especially electrochemical impedance spectroscopy (EIS), is one of the efficient approaches to dealing with biofilm-related issues. However, currently used EIS methods without a redox probe intend to detect all effects generated from media components, bacteria, and bacterial metabolites, which used to make the signals from the attached bacteria and biofilm weakened.

Polyampholyte-Wrapped Carbon Nanotubes: Preparation and Internalization by Embryonic Fibroblast Cells.

The cytotoxicity and cellular uptake of carbon nanotubes (CNTs) has recently attracted considerable interest because of the issue of biosphere-nanomaterial interactions. The biocompatibility of CNTs is determined by the metal impurities in the CNTs, the size of the CNTs and the CNT dispersion states; in particular, the type of surface modifications on the CNTs affects how they interact with cells and determines their cytotoxicity and cellular uptake. In this study, biocompatible single-walled carbon nanotubes (SWNTs) wrapped with a water-soluble copolymer, poly[2-(dimethylamino)ethyl methacrylate-co-methacrylic acid] (PDM), were prepared.

Cellular uptake, cytotoxicity, and ROS generation with silica/conducting polymer core/shell nanospheres.

The cellular response to conducting polymer (CP) nanospheres with similar physical properties was evaluated by in vitro cellular uptake and cytotoxicity in mouse macrophage RAW 264.7 and rat pheochromocytoma PC-12 cells. Four different CPs (polythiophene, poly(3,4-ethylenedioxythiophene), polyaniline, and polypyrrole) were deposited onto silica nanoparticles with a diameter of ca.

Flexible and transparent graphene films as acoustic actuator electrodes using inkjet printing.

Flexible and transparent graphene films have been fabricated via inkjet printing and vapor deposition (VDP) methods, and the graphene-based acoustic actuator could be used as an extremely thin and lightweight loudspeaker.

Sensitive and molecular size-selective detection of proteins using a chip-based and heteroliganded gold nanoisland by localized surface plasmon resonance spectroscopy.

A highly sensitive and molecular size-selective method for the detection of proteins using heteroliganded gold nanoislands and localized surface plasmon resonance (LSPR) is described. Two different heteroligands with different chain lengths (3-mercaptopionicacid and decanethiol) were used in fabricating nanoholes for the size-dependent separation of a protein in comparison with its aggregate. Their ratios on gold nanoisland were optimized for the sensitive detection of superoxide dismutase (SOD1).

Carbon nanotubes: are they dispersed or dissolved in liquids?

Carbon nanotubes (CNTs) constitute a novel class of nanomaterials with remarkable applications in diverse domains. However, the main intrincsic problem of CNTs is their insolubility or very poor solubility in most of the common solvents. The basic key question here is: are carbon nanotubes dissolved or dispersed in liquids, specifically in water? When analyzing the scientific research articles published in various leading journals, we found that many researchers confused between "dispersion" and "solubilization" and use the terms interchangeably, particularly when stating the interaction of CNTs with liquids.