Nanoscience and nanotechnology

Peptidic coating for gold nanospheres multifunctionalizable with photostable and photolabile moieties

by Valerio Voliani

Journal of Materials Chemistry 2012 (RSC), doi: 10.1039/C2JM31782F

A single-step method to coat and trifunctionalize water-dispersed gold nanospheres (AuNss) with
carboxylic acids,... more A single-step method to coat and trifunctionalize water-dispersed gold nanospheres (AuNss) with
carboxylic acids, amines, and alkynes is reported. The coating is based on a mix of two hexa-peptides,
differing only in the C-terminal amino acid. The process yields AuNss that are non-cytotoxic, stable in
physiological environments, and which present three reactive surface groups allowing rapid, selective,
10 and modular conjugation (click- and peptide-reactions) to virtually any chosen biomolecule or
fluorophore. Conjugated nanostructures were analyzed in vitro and in living cells. Confocal imaging and
colocalization analyses demonstrate the presence and reactivity of three different types of covalent bonds
with payloads: two of these are photostable while one bond is photolabile and can be cleaved by *Wpower
irradiation with a 561-nm cw laser.

Single and Mixed Phase TiO2 Powders by Excess Hydrolysis of Titanium Alkoxide

by Material Science

To investigate excess-hydrolysis of titanium alkoxides, TiO2 powders were fabricated from titanium-tetra-isopropoxide... more To investigate excess-hydrolysis of titanium alkoxides, TiO2 powders were fabricated from titanium-tetra-isopropoxide using 6:1 and 100:1 H2O:Ti (r) ratios. Powders were dried and fired at a range of temperatures (≤800ºC). Hydroxylation and organic content in powders were characterised using ATR-FTIR, laser Raman microspectroscopy, and elemental microanalysis; surface area and pore size distribution were evaluated using N2 gas adsorption; phase composition was analysed using XRD and laser Raman microspectroscopy; and crystallite size was evaluated by XRD, TEM and SEM. Results showed near-complete hydrolysis in a predominantly aqueous medium (r = 100), resulting in precipitated crystalline powders exhibiting brookite and anatase, which begin to transform to rutile below 500°C. Powders precipitated in a predominantly organic medium (r = 6) underwent partial hydrolysis, were highly porous and exhibited an amorphous structure, with crystallisation of anatase occurring at ~300°C and transformation to rutile beginning at 500°-600°C.

High Density Growth of Indium seeded Silicon Nanowires in the Vapor phase of a High Boiling Point Solvent

by Hugh Geaney

Temperature dependent conductivity and structural properties of sol-gel prepared holmium doped Bi2O3 nanoceramic powder

by Prof.Dr. İbrahim USLU

İ. Taşçıoğlu, M. Arı, İ. Uslu, S. Koçyiğit, Y. Dağdemir, V. Çorumlu and Ş. Altındal
Ceramics International, CERI_5314
Accepted paper, Manuscript Number: CERI-D-12-00407R2

Holmium (Ho)-doped Bi2O3 nanoceramic powders derived from sol-gel method have been studied in terms of structural,... more Holmium (Ho)-doped Bi2O3 nanoceramic powders derived from sol-gel method have been studied in terms of structural, morphological, and electrical properties. The morphology of the nanoceramic materials was analyzed by scanning electron microscopy (SEM) and their structure by Xray powder diffraction (XRD). Temperature dependence of DC conductivity measurements of nanoceramic powders were carried out by using DC four-point probe technique (4PPT) in air at temperatures ranging from 429 °C to 896 °C (702-1169 K). Electrical conductivity results demonstrate that there is a sharp increase at around 700 °C, which indicates an existence of order-disorder transition. This result supported by the Differential Thermal Analyzer (DTA) curve and XRD pattern which show that the sample has stable high oxygen ionic conductivity fluorite type face centered cubic -phase. Electrical characteristics also show that the DC conductivity in the studied materials obeys Arrhenius relation with different activation energies and conduction mechanisms: two temperature regions with activation energies Ea1=1.40 eV (702-993 K) and Ea2=0.66 eV (1006-1169 K). The analysis of experimental data revealed that the translation motion of the charge carrier, oxygen vacancies, and space charge polarization are responsible for the change in activation energy as a function of temperature.

Nanoheterostructure cation exchange: anionic framework conservation

by Prashant Jain

Spatially indirect emission in a luminescent nanocrystal molecule

by Prashant Jain

Highly luminescent nanocrystals from removal of impurity atoms residual from ion-exchange synthesis

by Prashant Jain

Absence of the density minimum of supercooled water in hydrophobic confinement

by Marco Lagi

Vibrational characteristics of bilayer graphene sheets

by Rajib Chowdhury

Thin Solid Films
Volume 519, Issue 18, 1 July 2011, Pages 6026–6032

Bilayergraphenesheets (BLGSs) are currently receiving increasing attention. In this paper, the vibration... more Bilayergraphenesheets (BLGSs) are currently receiving increasing attention. In this paper, the vibration characteristics of BLGSs are investigated using analytical and atomistic finite element approaches. Various possible scenarios, namely different geometrical configuration (armchair and zigzag), boundary conditions, and aspect ratio are considered in the present study. The dynamic characteristics of BLGS studied have shown dependence on aspect ratio and the boundary conditions. The unique vibrational properties and large stiffness of BLGS identified in the present work make them suitable candidates for manufacturing nanosensors; electromechanical resonators also will aid the nanomaterials research community to design nanodevices.

Russia's innovation policy: stubborn path-dependencies and new approaches

by Evgeny Klochikhin

Klochikhin, E. (2012). Russia's innovation policy: stubborn path-dependencies and new approaches. Research Policy (article in press).

For the last twenty years Russia has been struggling to turn itself into an efficient market economy. Innovation and... more For the last twenty years Russia has been struggling to turn itself into an efficient market economy. Innovation and technological development are considered to be one of the best ways to achieve impressive results. The country has succeeded in retaining certain strengths of the Soviet science and technology system but it has often failed to address the former weaknesses and emerging challenges. There are a number of external and internal factors that make reforms inevitable and urgent. In the last five–six years the political leadership has started an unprecedented attempt to reverse the negative trends and boost Russia's innovation performance. This paper studies the new policy approaches and suggests several others that might be considered useful at this stage of the country's development. This work contributes to the wider debate on the heterogeneity of national innovation systems and adaptation of the respective analytical approach to the study of technological development of the emerging economies. It also provides a detailed review of the literature and data sources on the Russian science and technology, and aims to start filling in the gap in this seriously understudied research area.

Size Controlled Growth of Germanium Nanorods and Nanowires by Solution Pyrolysis Directly on a Substrate

by Hugh Geaney

New insight into the regeneration kinetics of organic dye sensitised solar cells

by Stefano Martiniani

Stefano Martiniani ,  Assaf Y. Anderson ,  ChunHung Law ,  Brian C. O'Regan and Claudia Barolo
Chem. Commun., 2012, 48, 2406-2408
DOI: 10.1039/C2CC17100G

The order of regeneration for DSCs based on two organic dyes has been investigated by transient absorption... more The order of regeneration for DSCs based on two organic dyes has been investigated by transient absorption spectroscopy on devices under operating conditions and determined to be 2nd order in iodide. The results shed light on the mechanism and limits to the regeneration rate relative to oxidation potential.

2D Gold Nanoparticle Structures Engineered Through DNA Tiles for Delivery and Therapy

by Kemal Keseroglu

A.Y. Sonay, K. Keseroglu, M. Culha
Nano Biomedicine and Engineering, Vol. 4, No. 1, pp. 17-22, 2012

Self-assembly of 13 nm gold nanoparticles (AuNPs) engineered into 2D structures in solution using DNA tiles for their... more Self-assembly of 13 nm gold nanoparticles (AuNPs) engineered into 2D structures in solution using DNA tiles for their possible use for gene delivery and photothermal therapy is reported. The two different DNA tiles were constructed and the AuNPs coated with oligonucleotides possessing complementary sequence from the free ends were hybridized with the sticky ends of the tiles. The DNA tiles were bind to each other by mixing the tile structures without a heating and cooling step. The constructed nanostructures were 5 to 7 DNA tiles long since heat was not used to elongate them. When the DNA tiles were bound to the AuNPs, it was observed that AuNPs tend to stay in close proximity by filling the gaps between tiles. The stability of the constructed structures was tested against DNase, a DNA cleaving enzyme, for possible applications for gene delivery and photothermal therapy. It was found that the AuNP bound DNA tile structures resist the DNase cleavage up to eighty percent. Due to the presence of the AuNPs in the structure, the enzyme cannot bind to DNA sequences and this increases the DNA tile structures’ stability.

The calibration of carbon nanotube based bio-nano sensors

by Rajib Chowdhury

Journal of Applied Physics, 107[12] (2010), pp. 124322:1-8.

We derive the calibration constants necessary for using single-walled carbon nanotubes (SWCNTs) as nano-scale mass... more We derive the calibration constants necessary for using single-walled carbon nanotubes (SWCNTs) as nano-scale mass sensors. The carbon nanotube resonators are assumed to be either in cantilevered or in bridged configurations. Two cases, namely when the added mass can be considered as a point mass and when the added mass is distributed over a larger area are considered. Closed-form transcendental equations have been derived for the frequency shift due to the added mass. Using the energy principles, generalized nondimensional calibration constants have been derived for an explicit relationship between the added mass and the frequency shift. A molecular mechanics model based on the universal force field potential is used to validate the new results presented. The results indicate that the distributed nature of the mass to be detected has considerable effect on the performance of the sensor.

Nanonechnology in Russia (Technovation) - accepted

by Konstantin Fursov

Karthick B and Ramesh Maheshwari, 2008. Lotus-Inspired Nanotechnology Applications.

by Karthick Balasubramanian

Resonance (Journal of science education from Indian Academy of Sciences, Bangalore). 1141-1145.

The water-repellent surface of lotus (Nelumbo nucifera) leaf and flower is due to nanosized wax papillae on the upper... more The water-repellent surface of lotus (Nelumbo nucifera) leaf and flower is due to nanosized wax papillae on the upper side of each epidermal cell. As a result, raindrops make a high contact angle with the papillae and roll off carrying dust and dirt particles, leaving the surface clean. This self-cleaning property of highly hydrophobic surfaces, termed as the lotus effect, has opened the possibilities of fabricating superhydrophobic surfaces for a variety of products.

Chemical synthesis and structural characterization of highly disordered Ni colloidal nanoparticles

by Leandro Socolovsky

Regenerative Nanomedicine: Ethical, Legal, and Social Issues

by Linda MacDonald Glenn

Co-authored with Dr. Jeannann S. Boyce, published in Methods in Molecular Biology, 2012

Advances in regenerative nanomedicine raise a host of ethical, legal, and social questions that healthcare providers... more Advances in regenerative nanomedicine raise a host of ethical, legal, and social questions that healthcare providers and scientists will need to consider. These questions and concerns include definitions, appropriate applications, dual use, potential risks, regulations, and access. In this chapter, we provide an overview of the questions and concerns and recommend proactive consideration and solutions.

Optoelectronic Properties of Carbon Nanorings: Excitonic Effects from Time-Dependent Density Functional Theory

by Bryan Wong

Journal of Physical Chemistry C, 113, 21921 (2009)

Self-Assembled Cyclic Oligothiophene Nanotubes: Electronic Properties from a Dispersion-Corrected Hybrid Functional

by Bryan Wong

Physical Review B, 84, 075115 (2011)

- Selected by the editor to appear in the August 22, 2011 issue of the "Virtual Journal of Nanoscale Science & Technology" (Volume 24, Issue 8)
http://link.aip.org/link/VIRT01/v24/i8/p92