Nanochemistry: November 2014

Saturday, November 29, 2014

Effects in cigarette smoke stimulated bronchial epithelial cells of a corticosteroid entrapped into nanostructured lipid carriers

Background: Nanomedicine studies have showed a great potential for drug delivery into the lung. In this manuscript nanostructured lipid carriers (NLC) containing Fluticasone propionate (FP) were prepared and their biocompatibility and effects in a human bronchial epithelial cell line (16-HBE) stimulated with cigarette smoke extracts (CSE) were tested. Results: Biocompatibility studies showed that the NLC did not induce cell necrosis or apoptosis. Moreover, it was confirmed that CSE increased intracellular ROS production and TLR4 expression in bronchial epithelial cells and that FP-loaded NLC were more effective than free drug in modulating these processes. Finally, the nanoparticles increased GSH levels improving cell protection against oxidative stress. Conclusions: The present study shows that NLC may be considered a promising strategy to improve corticosteroid mediated effects in cellular models associated to corticosteroid resistance. The NLC containing FP can be considered good systems for dosage forms useful for increasing the effectiveness of fluticasone decreasing its side effects.

Maria Bondì

Click for full article

Friday, November 28, 2014

Crystal lattice determination of ZnSe nanowires with polarization-dependent second harmonic generation microscopy

We demonstrate a noninvasive optical microscopy technique based on polarization-dependent second harmonic generation for determining the crystal lattice structure and microscopic heterogeneities within individual nanostructures. Differentiation between periodically twinned and wurtzite ZnSe nanowires (NWs) was demonstrated, and measurement of the cubic lattice rotation orientation around the NW axis was determined within 1° accuracy. Zinc blende NWs were differentiated from wurtzite. The technique can be used for quality inspection and optimization of growth conditions for nanostructures.

Richard Cisek, Danielle Tokarz, Nehad Hirmiz, Ankur Saxena, Alexander Shik, Harry E Ruda and Virginijus Barzda

Click for full article

Atomic layer deposition of lithium phosphates as solid-state electrolytes for all-solid-state microbatteries

Atomic layer deposition (ALD) has been shown as a powerful technique to build three-dimensional (3D) all-solid-state microbattery, because of its unique advantages in fabricating uniform and pinhole-free thin films in 3D structures. The development of solid-state electrolyte by ALD is a crucial step to achieve the fabrication of 3D all-solid-state microbattery by ALD. In this work, lithium phosphate solid-state electrolytes were grown by ALD at four different temperatures (250, 275, 300, and 325 °C) using two precursors (lithium tert-butoxide and trimethylphosphate). A linear dependence of film thickness on ALD cycle number was observed and uniform growth was achieved at all four temperatures. The growth rate was 0.57, 0.66, 0.69, and 0.72 Å/cycle at deposition temperatures of 250, 275, 300, and 325 °C, respectively. Furthermore, x-ray photoelectron spectroscopy confirmed the compositions and chemical structures of lithium phosphates deposited by ALD. Moreover, the lithium phosph...

Biqiong Wang, Jian Liu, Qian Sun, Ruying Li, Tsun-Kong Sham and Xueliang Sun

Click for full article

Nanoscale phase behavior on flat and curved membranes

The diverse physical properties of membranes play a critical role in many membrane associated biological processes. Proteins responsible for membrane transport can be affected by the lateral membrane order and lateral segregation of proteins is often controlled by the preference of certain membrane anchors for membrane phases having a physically ordered state. The dynamic properties of coexisting membrane phases are often studied by investigating their thermal behavior. Optical trapping of gold nanoparticles is a useful tool to generate local phase transitions in membranes. The high local temperatures surrounding an irradiated gold nanoparticle can be used to melt a part of a giant unilamellar lipid vesicle (GUV) which is then imaged using phase sensitive fluorophores embedded within the bilayer. By local melting of GUVs we reveal how a protein-free, one component lipid bilayer can mediate passive transport of fluorescent molecules by localized and transient pore formation. Also,...

Thomas Andersen, Azra Bahadori, Dino Ott, Anders Kyrsting, S Nader S Reihani and Poul M Bendix

Click for full article

Spatial resolution in thin film deposition on silicon surfaces by combining silylation and UV/ozonolysis

A simple procedure has been developed for the processing of silicon wafers in order to facilitate the spatially resolved growth of thin solid films on their surfaces. Specifically, a combination of silylation and UV/ozonolysis was tested as a way to control the concentration of the surface hydroxo groups required for subsequent atomic layer deposition (ALD) of metals or oxides. Water contact angle measurements were used to evaluate the hydrophilicity/hydrophobicity of the surface, a proxy for OH surface coverage, and to optimize the UV/ozonolysis treatment. Silylation with hexamethyldisilazane, trichloro(octadecyl)silane, or trimethylchlorosilane was found to be an efficient way to block the hydroxo sites and to passivate the underlying surface, and UV/O 3 treatments were shown to effectively remove the silylation layer and to regain the surface reactivity. Both O 3 and 185 nm UV radiation were determined necessary for the removal of the silylation layer, and ...

Lei Guo and Francisco Zaera

Click for full article

Fletching-shaped Bi 4 Te 3 –ZnTe heterostructure nanowires

We investigated Bi 4 Te 3 –ZnTe axial heterostructure nanowires grown by physical vapor transport at the substrate temperature of 450 °C, utilizing ZnTe as the source and Bi 2 Te 3 as the catalyst. The temperatures of the source and catalyst materials were individually controlled by separating the source and catalyst boats. The axial heterostructure nanowires consisted of ZnTe and Bi 4 Te 3 segments. The Bi 4 Te 3 segment had an interesting fletching shape with three wings surrounded by a ZnO shell. A systematic redshift in the nanowire’s photoluminescence was observed as the excitation laser spot was moved from the heterojunction toward the root of the ZnTe segment, attributed to the formation of deep defect states under the Te-rich environment that resulted from using Bi 2 Te 3 as the catalyst instead of Bi.

Man Suk Song and Yong Kim

Click for full article

Nanostructured TiO 2 /carbon nanosheet hybrid electrode for high-rate thin-film lithium-ion batteries

Heterogeneous nanostructured electrodes using carbon nanosheets (CNS) and TiO 2 exhibit high electronic and ionic conductivity. In order to realize the chip level power sources, it is necessary to employ microelectronic compatible techniques for the fabrication and characterization of TiO 2 -CNS thin-film electrodes. To achieve this, vertically standing CNS grown through a catalytic free approach on a TiN/SiO 2 /Si substrate by plasma enhanced chemical vapour deposition (PECVD) was used. The substrate-attached CNS is responsible for the sufficient electronic conduction and increased surface-to-volume ratio due to its unique morphology. Atomic layer deposition (ALD) of nanostructured amorphous TiO 2 on CNS provides enhanced Li storage capacity, high rate performance and stable cycling. The amount of deposited TiO 2 masks the underlying CNS, thereby controlling the accessibility of CNS, which gets reflected in the total electrochemica...

S Moitzheim, C S Nimisha, Shaoren Deng, Daire J Cott, C Detavernier and P M Vereecken

Click for full article

Synthesis of nano-bowls with a Janus template

Nanoscale , 2015, Advance Article

DOI: 10.1039/C4NR05153J, Paper

Alexander H. Mo, Preston B. Landon, Chris D. Emerson, Chen Zhang, Paula Anzenberg, Siddhartha Akkiraju, Ratnesh Lal

Silica nanobowls can be formed by the removal of polystyrene from a spontaneously formed Janus template.

To cite this article before page numbers are assigned, use the DOI form of citation above.

The content of this RSS Feed (c) The Royal Society of Chemistry

Pages

Saturday, November 29, 2014

Friday, November 28, 2014

Thursday, November 27, 2014

Friends

Pageviews

Donations