A novel route for the synthesis of indium nanoparticles in ionic liquid

In this paper, we report a novel preparation of indium nanoparticles by the reduction of indium chloride in ionic liquid by methanolic solution of NaBH₄. The particles are characterized by means of transmission electron microscopy (TEM), X-ray diffraction and UV-visible studies indicated that the powder consist of the cubic phase of indium. The particle size of indium nanoparticles is in the range of 20 nm mean diameter by Transmission electron microscopy (TEM). The samples display a strong surface plasma absorption band at 231 nm, which indicates that the sample is metal indium and the particle size is less than 20 nm. The thermal analysis of the sample indicate indium not indium oxide. Electrochemical studies show that indium nanoparticles have very good electrical properties.     

Alignment of liquid crystals doped with nickel nanoparticles containing different morphologies

Uniform homeotropic and homogeneous alignment of liquid crystals (LCs) is facilely achieved by dispersing Ni nanoparticles (Ni NPs) into the LCs. The alignment mode depends on the morphology of the Ni NPs. The mechanism of NP-induced LC alignment is elucidated clearly, indicating that the perfect orientation arises from the adsorption of Ni NPs on the substrate.     

Effect of reducing agent on the synthesis of nickel nanoparticles

Synthesis of nickel nano-particles with a coating of a hydrophilic surfactant has been carried out by use of sodium borohydride and sodium formaldehyde sulfoxylate (SFS) in aqueous medium. It is observed that an ideal temperature range for formation of nickel nanoparticles is between 50 and 100 °C. Phase-pure nano-nickel can be obtained by use of SFS. X-ray diffraction measurements (XRD) revealed broad pattern for fcc crystal structure of nickel metal with particle diameter of about 10-15 nm. Scanning Electron Microscopy (SEM) showed that there is clustering of spherical particles in dry state and Transmission Electron Microscopy (TEM) gave a particle size of about less than 10 nm.     

一种制备ZnO纳米颗粒的新方法

提出了一种制备ZnO纳米颗粒的新方法。在金属钠的液氨溶液中还原硝酸锌,所形成的金属Zn自然氧化而制得ZnO颗粒。为了研究表面修饰对产物形貌、粒径和性能的影响,制备了十二烷基磺酸钠（SDS）修饰的ZnO纳米颗粒。采用X射线粉末衍射仪（XRD）、透射电子显微镜（TEM）、傅立叶变换红外光谱仪（FT-IR）、热重及差热分析仪（TG-DTA）等手段对产物进行了表征。结果表明采用该方法可制得具有六方纤锌矿结构的ZnO颗粒,未修饰ZnO颗粒团聚较为严重;修饰的ZnO纳米颗粒呈棒状,分散较好。红外和热分析表明SDS修饰在了ZnO纳米颗粒表面。测试了所制备ZnO颗粒的紫外可见吸收（UV-Vis）和光致发光（PL）谱,均出现了ZnO的特征谱带。提出的方法也适用于制备其它金属或氧化物纳米材料。     

Banana peel extract mediated novel route for the synthesis of palladium nanoparticles

Bio-inspired palladium nanoparticles were synthesized by using banana peel extract (BPE), a non-toxic eco-friendly material. Boiled, crushed, acetone precipitated, air-dried peel powder was used to reduce palladium chloride. The palladium nanoparticles were characterized by using UV-Visible spectroscopy, scanning electron microscope-energy dispersive spectra (SEM-EDS) and X-ray diffraction (XRD) analysis. Dynamic light scattering (DLS) studies revealed the average size of nanoparticles to be 50 nm. Fourier transform infra red spectroscopy (FTIR) implicated the role of carboxyl, amine and hydroxyl groups in the synthetic process. This paper thus describes a novel green method for the synthesis of palladium nanoparticles.     

Preparation and electrochemical performance of nano-scale nickel hydroxide with different shapes

Platelet-like, flake-like, and needle-like nano-scale β-Ni(OH)₂ particles were prepared by coordination homogeneous precipitation method in this paper. X-ray diffraction (XRD), transmission electron microscopy (TEM) and infrared absorption spectra (IR) were used to characterize the microstructure and morphology of the products. The nano-scale Ni(OH)₂ composite electrodes were prepared by mixing 10 wt.% samples with spherical Ni(OH)₂ to carry out charge-discharge test. The results show that the nano-scale Ni(OH)₂ composite electrodes have higher discharge specific capacity, and the nickel hydroxide nanoneedles show a better adulteration performance than the others.     

A novel application of iron oxide nanoparticles for detection of hydrogen peroxide in acid rain

Determining the concentration of hydrogen peroxide (H₂O₂) is of great importance in food, pharmaceutical, environmental and clinical analyses. Horseradish peroxidase (HRP), an enzyme specifically catalyzing the oxidative reaction of H₂O₂ to develop color reaction, has been widely used for measuring H₂O₂ concentration. However, owing to the instability and high cost of this enzyme, discovering efficient mimics of peroxidase has been important to conquer these disadvantages of protein catalyst. Recently we have found that Fe₃O₄ magnetic nanoparticles (Fe₃O₄ MNPs) possess intrinsic peroxidase-like activity, which can catalyze oxidation of various peroxidase substrates in the presence of H₂O₂. Based on this finding, we developed a spectrometric method using Fe₃O₄ MNPs as a catalyst to determine H₂O₂ in rainwater. Our data show that the Fe₃O₄ MNPs are efficient catalysts to determine H₂O₂ in rainwater. Compared to HRP, the Fe₃O₄ MNPs are reusable and economical and these characteristics make the particles a board range of applications in determining H₂O₂ in the rainwater.     

Ag-catalyzed synthesis of ultrafine nickel nanoparticles: A facile way to size control

We report here a facile strategy, Ag-catalyzed reduction of Ni²⁺ ions, for the synthesis of metallic nickel nanoparticles. The phase structure and morphology of particles were analyzed by means of X-ray diffraction and scanning electron microscopy. It was found that the resultant Ni nanoparticles had narrow size distribution, and the control of particle size could be easily achieved through manipulation of the molar ratio between nickel salts and silver seeds. XRD analysis of the final particles showed the crystalline nickel structure and the presence of metallic Ag, which was influenced by the Ni/Ag molar ratio. The effects of reduction temperature on the final particle size were also investigated.     

A novel microwave method for measuring the complex dielectric constant of polymer thin sheets

A new method of measuring the complex dielectric constant of a thin sheet of polymer samples at microwave frequency is presented. In order to obtain the complex dielectric constant in terms of reflection coefficient, a higher order power series solution has been introduced. Application of lower order power series solution to the greater thickness of the sample requires a frequency of less than 1.5 GHz. To overcome this constraint and to extend the range of working frequency, the higher order power series solution is used to obtain the complex dielectric constant. This method is used to measure the complex dielectric constant of poly(ethylene vinyl acetate), polyurethane, polyvinyl acetate, and polystyrene. The results obtained are in good agreement with literature. Electronic Publication     

A simple microemulsion based method for the synthesis of gold nanoparticles

The production of gold nanoparticles and nanoplates by enzymatically-synthesized lauroyl glucose, lauroyl fructose and lauroyl ascorbate is described. These emulsifiers formed oil-in-water microemulsions with toluene and the available reducing groups brought about a rapid reduction of chloroauric acid (HAuCl₄). Gold nanoparticles could thus be synthesized without the use of an additional reducing agent. Optical images, UV–visible spectroscopy, scanning electron microscopy, energy dispersive spectra (SEM–EDS) and X-ray diffraction (XRD) analysis revealed the presence of gold nanoparticles, which on further incubation aggregated into nanoplates. This paper thus describes a novel application of the enzymatically-synthesized esters.     

Interactions of human endothelial cells with gold nanoparticles of different morphologies

The interactions between noncancerous, primary endothelial cells and gold nanoparticles with different morphologies but the same ligand capping are investigated. The endothelial cells are incubated with gold nanospheres, nanorods, hollow gold spheres, and core/shell silica/gold nanocrystals, which are coated with monocarboxy (1-mercaptoundec-11-yl) hexaethylene glycol (OEG). Cell viability studies show that all types of gold particles are noncytotoxic. The number of particles taken up by the cells is estimated using inductively coupled plasma (ICP), and are found to differ depending on particle morphology. The above results are discussed with respect to heating efficiency. Using experimental data reported earlier and theoretical model calculations which take into account the physical properties and distribution of particles in the cellular microenvironment, it is found that collective heating effects of several cells loaded with nanoparticles must be included to explain the observed viability of the endothelial cells.     

Gold nanoparticles loaded into niosomes: A novel approach for enhanced antitumor activity against human ovarian cancer

In the current study, gold nanoparticles (AuNPs) were prepared using the green synthesis method using Artemisia annua extract, loaded into niosomes, and investigated their cytotoxicity and apoptotic effects. To optimize the niosomal formulation containing AuNPs, the effects of surfactants: cholesterol molar ratio, Span 60: Tween 60 M ratio, and AuNP concentration (µg/mL) were investigated. After examining the drug release profile, mathematical models were assessed to predict release kinetic. The cytotoxicity of noisome encapsulated AuNPs and free AuNPs was evaluated against human ovarian cancer cell line (A2780) by MTT assay. The apoptotic/necrosis ratio was studied using flow cytometry as well as Real-Time PCR was used for the Bax and Bcl-2 apoptosis gene expression. The results showed that the entrapment efficiency and particle size of optimized niosomal formulation encapsulated AuNPs were 34.49%±0.84 and 153.6 ± 4.62 nm with a regular spherical shape, respectively. The release profile of AuNPs from niosomal formulation was 59%±1.0 after 8 h suggesting the controlled release profile. This formulation exerted dose-dependent cytotoxicity against the A2780 cells via induction of apoptosis and significant upregulation of mRNA expression of Bax gene; while expression of anti-apoptotic gene Bcl-2 was down-regulated. Thus, the findings suggest that AuNP-loaded niosomal formulation is considered a promising and suitable targeted system for improving anti-tumor activity against A2780 cells.     

超滤分离蛋白质过程快速优化新技术及其应用

介绍了蛋白质超滤分离快速优化新技术、新方法,包括脉冲进样技术,载体相超滤技术、参数连续变化超滤技术以及在这些技术基础上建立的超滤分离快速优化新方法,克服了常规蛋白质超滤分离过程优化中存在的实验工作量大、蛋白质消耗多、费时以及费用高等缺点.利用该方法对以溶菌酶和卵清蛋白为模型蛋白质的混合体系进行了研究,筛选出合适的超滤膜...     

A novel vehicle for local protein delivery to the inner ear: injectable and biodegradable thermosensitive hydrogel loaded with PLGA nanoparticles

Delivery of biomacromolecular drugs into the inner ear is challenging, mainly because of their inherent instability as well as physiological and anatomical barriers. Therefore, protein-friendly, hydrogel-based delivery systems following local administration are being developed for inner ear therapy. Herein, biodegradable poly(lactic-co-glycolic acid) (PLGA) nanoparticles (NPs) containing interferon α-2?b (IFN α-2?b) were loaded in chitosan/glycerophosphate (CS/GP)-based thermosensitive hydrogel for IFN delivery by intratympanic injection. The injectable hydrogel possessed a physiological pH and formed semi-solid gel at 37?°C, with good swelling and deswelling properties. The CS/GP hydrogel could slowly degrade as visualized by scanning electron microscopy (SEM). The presence of NPs in CS/GP gel largely influenced in vitro drug release. In the guinea pig cochlea, a 1.5- to 3-fold increase in the drug exposure time of NPs-CS/GP was found than those of the solution, NPs and IFN-loaded hydrogel. Most importantly, a prolonged residence time was attained without obvious histological changes in the inner ear. This biodegradable, injectable, and thermosensitive NPs-CS/GP system may allow longer delivery of protein drugs to the inner ear, thus may be a potential novel vehicle for inner ear therapy.     

One-step solution auto-combustion process for the rapid synthesis of crystalline phase iron oxide nanoparticles with improved magnetic and photocatalytic properties

We report the solution auto-combustion (AC) process for the rapid synthesis of Fe₃O₄ nanoparticles derived from the sol–gel (SG) process. The citric acid (CA) and tartaric acid (TA) is used as gelling agents in the SG process, where the citric acid turns into a fuel that combusts the gel and yields a highly magnetic crystalline phase Fe₃O₄ nanoparticles in one step with an average particle size of 50 nm. In contrast, the citric acid at different concentrations and tartaric acid at any concentrations do not lead to any combustion process and yield amorphous iron oxides. Upon annealing, these CA and TA derived iron oxide samples are turned to crystalline phase α-Fe₂O₃ particles. In contrast, the as-synthesized AC sample (i.e. Fe₃O₄) is oxidized to γ-Fe₂O₃ phase, which is confirmed from their respective XRD, Rietveld refinement and XPS studies. All the synthesized iron oxide phases showed broad visible light absorption. The room temperature M?H hysteresis curves obtained from VSM revealed that the Fe₃O₄ and α-Fe₂O₃/γ-Fe₂O₃ phases exhibit super-paramagnetic and ferromagnetic properties, respectively. The photocatalytic efficiencies of the samples are found to be in the order of Fe₃O₄ > γ-Fe₂O₃ > α-Fe₂O₃ with 98, 87, 79/73% degradation of rhodamine B dye at the end of 3 h and H₂ evolution rate over these systems is found to be 2.1, 1.3 and 0.92/0.89 mmol/h/g, respectively under simulated solar light irradiation. The photocatalytic recycle studies demonstrated that all the synthesized photocatalysts possess excellent chemical and photo-stabilities.     

A new two-phase system for the preparation of nearly monodisperse silver nanoparticles

Nearly monodisperse silver nanoparticles were prepared in a two-phase water-cyclohexane system. Aqueous silver nitrate was reduced by the product of the reaction of aqueous hydrazine with benzyl aldehyde in cyclohexane to form, in the presence of oleic acid, cyclohexane-soluble silver nanoparticles. The silver nanoparticles were examined by transmission electron microscopy (TEM), UV-visible spectroscopy (UV-vis), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). The nanoparticles are relatively monodisperse (diameter less than 6 nm) and have good stability in cyclohexane due to the oleic acid adsorbed on their surfaces. These silver nanoparticles were successfully assembled into a powder with a face-centered-cubic structure by slow evaporation of the solvent. With some change in particle size, these silver nanoparticles could be transferred from cyclohexane to water by the addition of cetyltrimethylammonium bromide.