International Journal of Nano Dimension
Volume:5 Issue: 4, Autumn 2014

In recent years, it has become evident that it is necessary to systematically and accurately define particle characteristics in order to understand the potential toxicity of nanoparticles to biological systems. The properties that need to be emphasized are size, shape, dispersion, doping, aggregation, functionalization, physical and chemical properties, surface area, and surface chemistry. Route of exposure are Oral, dermal, inhalation and injection. Toxicity screening strategy; In Vitro Assays, In Vivo Assays and cell type are also an important parameter to consider while studying the toxicity of nanoparticles. These analytical methods used to check the toxicity require expensive equipment and sampling, which are time consuming. Using the bacteria, as a biosensor, solves these problems. This method is sensitive, low-cost and easily reproducible and takes 5 to 30 minutes to predict toxicity. This review focuses to develop a synergy among different paradigm of Nanomaterials characterization.

A simple method has been employed to synthesize Copper and Copper oxide nanoparticles from Copper (II) succinate precursor by thermal decomposition method using oleylamine as a capping agent. The particles synthesized with oleylamine and triphenylphosphine were well dispersed nanoparticles obtained from X-ray Diffraction (XRD). The Synthesized copper nanoparticles were characterized by UV-Visible, Fourier transfer Infrared Spectra, X-ray Diffraction, Atomic force microscope (AFM), Scanning electron microscope (SEM) and Cyclic Voltammetry (CV).

A useful nanophotocatalyst (La,S-TiO2) was prepared by a sol-gel method and characterized by UV–vis diffuse reflectance spectroscopy (DRS), X-ray diffraction (XRD), photoluminescence emission spectroscopy (PL) and scanning electron microscopy (FESEM). The results showed that the La,S-TiO2, which calcined at 550 °C, contained only anatase phaseand its crystal size was 23 nm. In addition, the FESEM analysis indicates that the La,S-TiO2 nano particles with diameter of 20 to 25 nm could have a good dispersion in solution. In order to evaluate of activity of the modified synthesized photocatalyst (La,S-TiO2), comparison between modified synthesized TiO2 (La,S-TiO2) and pure synthesized TiO2 for degradation of Methyl Orange was investigated. It was found that the modified synthesized photocatalysis (La,S-TiO2) has much higher photocatalytic activity than undoped TiO2 for the degradation of contamination.

In this study, Zinc Oxide nanoparticles (ZnONPs) were synthesized by chemical method and their antibacterial efficiency against a clinical isolate of Staphylococcus aureus was studied. The Zinc Oxide nanoparticles have shown a commendable inhibition effect on the growth of most notorious bacterial pathogen S.aureus. The nanoparticles size and shapes were characterized by transmission electron microscopy (TEM). The rod shaped zinc nanoparticles were formed as as a result of fast reduction rate of the precursor. The shape controlled nanocrystals possess well defined surfaces and morphologies and showed an excellent antibacterial property against clinical bacterial strain S. aureus.

Nanocrystalline particles of Cerium Oxide (CeO2) have been prepared by the chemical precipitation method using Cerium nitrate and Urea with a molar ratio of 1:2. The results revealed that the formation of CeO2 fine particles is influenced by molar ratio of metal nitrates to fuel. Well faceted CeO2 nanoparticles, were synthesized by thermal-assisted dissociation method at reflux temperature in a short period of time. A possible mechanism for synthesis of such highly pure and stable nanoparticles is tentatively proposed by thermogravimetry-differential thermal analysis (TG –DTA) study. The powders were investigated by X-ray diffraction (XRD), Transmission electron microscopy (TEM), selected area electron diffraction (SAED), high resolution transmission electron microscopy (HRTEM). In addition, uniform particles, size distribution and purity of samples are highly dependent on the applied chemical precipitation method. Raman spectroscopy and Electron Diffraction Analysis confirmed the fluorite structure of bulk CeO2.

Sol–gel chemistry is an efficient tool to control the morphology and reactivity of solids. Drying is the crucial step due to the capillary forces exerted during the classic ambient drying process, which induces the collapse of the wet gel porosity. The use of N, N-dimethylformamide (DMF), a newly found DCCA were found to be effective in the sol–gel synthesis of crack-free silica gel monolith from tetraethoxysilane (TEOS) via acid catalyzed. We investigate the effect of N, N- dimethylformamide as DCCAs in simple inorganic silica obtained from tetraethoxysilane (TEOS) and the effects drying control chemical additives (DCCA) on gelatin time and physical properties of the dry gel were examined in an acidic silica sol-gel process.

Polyimide/Nickel oxide (polyimide/NiO) nanocomposite was successfully synthesized by sol gel technique, using Pyromellitic dianhydriede (PMDA), 4,4-oxydianiline (ODA) and N,N-dimethylacetamide (DMAC) and 10 wt% Nickel titanate nanopowders (NPs). Fourier transform infrared spectrometry (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and vibrating sample magnetometer (VSM) were used to characterize the structure and properties of the obtained nanocomposite. The results indicated that the average size of polyimide/NiO nanocomposite were estimated 65nm. Saturation magnetizations results indicate that by adding of NiO nanoparticles in polyimide matrix, magnetization decreases. The superparamagnetic behavior for NiO nanoparticles and polyimide/NiO nanocomposite of 10 wt% is reported whereas Polyimide has diamagnetic behavior.

A new three-dimensional unit cell model has been developed for modeling three constituent phases including inclusion, interphase and matrix. The total elastic modulus of nano-composite is evaluated. Numerical results are in good agreement with the previous proposed theoretical modeling. Higher matrix and inclusion elastic modulus both can dramatically influence the total elastic modulus.

Effects were studied of 200 ppm silver and copper nano-suspensions, with size range from 20 to 80 nm, on the hardness of particleboards produced at an industrial scale at the Iran-Choob Factory, Iran. Metal nano-suspensions were added to the mat at two levels of 100 and 150 milli-liters/kg dry weight wood particles, and the results were compared with those of the control panels. Results showed that the high thermal conductivity coefficient of silver nanoparticles broke down part of the resin bonds; it also heat-treated the surface wood particles, resulting in significant decrease in the hardness of treatment with 150 mL/kg. However, in the nanocopper-treated panels, no significant change was observed due to the lower thermal conductivity coefficient of copper; furthermore, as to the formation of higher hydroxyl bonds, it even slightly increased. High significant correlations were determined between most of the physical and mechanical properties of the panels.

ZnO and ZrO2 photo catalysts were synthesized by sol-gel auto combustion method. The products were characterized by X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). Structural and morphological properties of nano particles were investigated and the average crystalline size of ZnO and ZrO2 was obtained 44 and 51 nm, respectively. Also, photo catalytic degradation of Nitro phenol from aqueous solution by using nano scale ZnO and ZrO2 powders under UV-C light irradiation was studied and degradation of Nitro phenol was 98% for ZnO in 40 minutes and 83% in 100 min for ZrO2.

Ceramic Ultrafiltration membranes are considered as an alternative for the treatment of both stable water-in-oil and oil-in-water emulsions proved to be more effective in comparison with other conventional techniques. In this study, symmetric macro-porous ceramic membranes are prepared through dry pressing of α-alumina powder and the addition of various binders including Poly (vinyl alcohol). The disk is sintered after the organic material is burned away and the porosity can also be adjusted by the variation of sintering temperature. The results show that the fabrication of compact membrane supports can be done by increasing the sintering temperature which leads to grain size reduction. Moreover, application of different binders and additives result in various supports possessing different pore size and size distributions. Scanning electron Microscope (SEM) micrographs illustrate the surface and grain size distributions caused by various binders. These membranes can be used for microfiltration at elevated temperatures and extreme environmental conditions and also as porous supports for the fabrication of composite-asymmetric nanofiltration membranes.

In this study the effect of using multi-walled carbon nanotube (MWCNT) on flexural and compressive strengths, ultimate displacement and energy absorption capability of standard cement mortar considering different weight percentages of nanotubes as well as different dispersion methods has been investigated. Influential point in adding nanotubes to the composites is their proper dispersion, which is considered by comparing the results of two different dispersion methods. According to the test results and scanning electron microscope (SEM) images, the method using functionalized MWCNTs together with ultrasonication is pointed as an appropriate dispersion method. Using nanotubes resulted in significantly increase in the flexural strength and specially toughness of cement mortar which represents the ability of properly dispersed nanotubes in bridging and closure of the micro cracks. Finally, the observed results has been assessed with a statistical analysis and validated with acceptable significance levels.

A novel complex of cadmium (II) [CdL0.5(NO3)(H2O)](1), L= N,N-bis (O-hydroxyacetophenone) ethylene diamine, have been synthesized as single crystal and nano size. Compound 1 in nano size was obtained under sonochemical irradiation and has been characterized by IR, 1HNMR spectroscopy, X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The gray single crystal of compound 1 has been synthesized by slow evaporation and characterized by IR, 1HNMR spectroscopy. Then, Compound 1 in nano size was used as initial reagent to obtain nano-particles of cadmium (II) oxide at 673 K by direct calcination. The obtained CdO nano-particles were characterized by XRD pattern as well as SEM images.

Porous silicon samples were prepared by electrochemical etching method for different etching times. The structural properties of porous silicon (PS) samples were determined from the Atomic Force Microscopy (AFM) measurements. The surface mean root square roughness (σ rms) changes as function of porosity were studied, and the influence of etching time on porosity and roughness was studied too. UV-Vis-NIR Spectrophotometer with integrating sphere accessory used to measure the specular reflectance (Rspec) and scattered light (Dsca) for all samples. Changes of scattered light intensity with σ rms were studied. Theoretical and measured values were compared and they were almost the same.