Structural and optical investigations of SiO<SUB>2</SUB>-CdS core-shell particles

Cadmium sulfide nanoparticles (~5 nm), chemically capped using thioglycerol molecules, have been anchored onto silica particles (~80 nm) functionalized with 3-aminopropyltrimethoxysilane. Transmission electron microscopy clearly showed that at a low concentration of cadmium sulfide, nanoparticles were discretely and more or less uniformly attached onto the silica particles. At a high concentration of cadmium sulfide nanoparticles, an approximately 6-nm-thick compact shell of cadmium sulfide was formed on the silica particles. In both cases the nanocrystalline nature of cadmium sulfide particles was preserved, as is evident from X-ray diffraction and optical absorption spectra

Comparative assessment of the orthodontic wire&amp;rsquo;s friction coated with zinc oxide nanoparticles by two methods of chemical precipitation and hydrothermal process

Introduction: In orthodontic treatment with sliding technique, reduction of frictional forces could result in a more effective treatment. Recently, wire coating with nanoparticles were proposed to reduce frictional forces.Aim: The aim of this study was to evaluate the effect of coating wires with zinc oxide nanoparticle by two methods of chemical precipitation and direct hydrothermal process on the wire-bracket frictional force.Materials and methods: In this study, 30 pieces of stainless-steel arch wire with and without zinc oxide nanoparticles and 30 metal brackets with a 0.022-inch slot were divided into three groups: group 1 &amp;ndash; control (uncoated wires); group 2 &amp;ndash; wires coated with zinc oxide nanoparticles, and group 3 &amp;ndash; wires with a thin layer of nanostructured zinc oxide. In the first method, the nanoparticles were made by chemical precipitation method, and in the second method, nanostructure was directly formed on wires. Additionally, SEM observations were used to confirm the presence of nanoparticles on the wires. Friction between wires and brackets was measured using Universal Testing Machine. SPSS v. 20 and ANOVA test was used in order to analyze the data. The significance level was considered as p&amp;lt;0.05.Results: The mean value of frictional forces were 1.73 N, 1.52 N, and 1.56 N in the control group, chemical precipitation method group and thin layer of nanostructured zinc oxide group, respectively. There was no significant difference in friction rate between brackets and stainless-steel wire coated by any of these two methods (p=0.555).Conclusion: Coating of orthodontic wires with zinc oxide nanoparticles can reduce friction with brackets during sliding. There was no difference in the established value of friction between coating of orthodontic wires with chemical precipitation method and thin layer coating method

Radiofrequency electric field hyperthermia with gold nanostructures: role of particle shape and surface chemistry

<p>Hyperthermia treatment of cancerous cells has been recently developed drastically with the help of nanostructures. Heating of gold nanoparticles in non-invasive radiofrequency electric field (RF-EF) is a promising and unique technique for cancer hyperthermia. However, because of differences between particles (i.e. their surface chemistry and dispersion medium) and between RF-EF sources, the research community has not reached a consensus yet. Here, we report the results of investigations on heating of gold nanoparticles and gold nanorods under RF-EF and feasibility of <i>in-vitro</i> cancer hyperthermia. The heating experiments were performed to investigate the role of particle shape and surface chemistry (CTAB, citrate and PEG molecules). <i>In-vitro</i> hyperthermia was performed on human pancreatic cancer cell (MIA Paca-2) with PEG-coated GNPs and GNRs at concentrations that were found non-toxic based on the results of cytotoxicity assay. Application of RF-EF on cells treated with PEG-GNPs and PEG-GNRs proved highly effective in killing cells.</p

Photoluminescent core-shell particles of organic dye in silica

Using a single silica precursor, Rhodamine 6G organic dye molecules have been entrapped in silica particles resulting into core-shell particles of ~500 nm diameter. Energy dispersive X-ray analysis, X-ray photoelectron spectroscopy and transmission electron microscopy analysis reveals that dye molecules are trapped inside the silica particles. Photoluminescence investigations show that highly luminescent and photostable core-shell particles are formed. Such core-shell particles can be easily suspended in water and would be useful for a variety of applications. However, there is a blue shift in the photoluminescence wavelength in case of core-shell particles compared to bare dye powder sample

Harnessing the Cancer Radiation Therapy by Lanthanide-Doped Zinc Oxide Based Theranostic Nanoparticles

In this paper, doping of europium (Eu) and gadolinium (Gd) as high-<i>Z</i> elements into zinc oxide (ZnO) nanoparticles (NPs) was designed to optimize restricted energy absorption from a conventional radiation therapy by X-ray. Gd/Eu-doped ZnO NPs with a size of 9 nm were synthesized by a chemical precipitation method. The cytotoxic effects of Eu/Gd-doped ZnO NPs were determined using MTT assay in L929, HeLa, and PC3 cell lines under dark conditions as well as exposure to ultraviolet, X-ray, and γ radiation. Doped NPs at 20 μg/mL concentration under an X-ray dose of 2 Gy were as efficient as 6 Gy X-ray radiation on untreated cells. It is thus suggested that the doped NPs may be used as photoinducers to increase the efficacy of X-rays within the cells, consequently, cancer cell death. The doped NPs also could reduce the received dose by normal cells around the tumor. Additionally, we evaluated the diagnostic efficacy of doped NPs as CT/MRI nanoprobes. Results showed an efficient theranostic nanoparticulate system for simultaneous CT/MR imaging and cancer treatment

Multiferroic TbMnO<SUB>3</SUB> nanoparticles

We report on the synthesis of TbMnO3 nanoparticles by chemical co-precipitation route and their structural, chemical bonding, magnetic and dielectric properties. It is shown that the interesting multiferroic properties of this system as reflected by the concurrent occurrence of magnetic and dielectric transitions are retained in the nanoparticles (size ~40 nm). However, the nanoparticle constitution and properties are seen to depend significantly on the calcination temperature. While the nanoparticles obtained by calcination at 800 &#176;C correspond very well with the reported properties of single phase TbMnO3 (all the key magnetic and dielectric features near 7, 27 and 41 K, albeit with reduced dielectric constant) the nanoparticles obtained by calcination at 900 &#176;C develop a Tb deficient skin which softens the transitions, reducing the dielectric constant further