Journal of Nanoanalysis
Volume:4 Issue: 2, Jun 2017

The highest concentration of aluminium (Al) in human blood has toxic effect and so, extraction from human body is very important. In this procedure, an efficient and new method based on graphene oxide nanoparticles (GONPs) dispersed in ionic liquid (IL) was used for in-vitro separation/extraction of trace Al from the blood of dialysis patients by ultrasound assisted-dispersive-micro solid phase extraction (USA-D-μSPE) procedure. Under optimized conditions, the linear range (LR), limit of detection (LOD) and preconcentration factor (PF) were obtained 0.1–4.8 μg L−1, 0.02 μg L−1 and 25 for blood samples, respectively (RSD<5%). The results of blood samples showed us, that the aluminum concentration after dialysis was higher than before dialysis (128.6±6.7 vs 31.8±1.6, P<0.05). The mean of blood aluminum was significantly higher in dialysis patients than in normal control, respectively (113 5±7.12 vs 1.2±0.1). The developed method based on GONPs/IL was successfully applied for extraction of critical level aluminum from human blood and suggested for in-vivo extraction from human body of dialysis patients after supporting on an appropriate surfacewith biocompatible materials within the human body.

In the present study, we carried out chemical synthesis and characterization of Fe3O4@PEG-Au as a magnetic nanocomposite in aqueous solution by chemical co-precipitation of Fe3+ and Fe2+ ions and encapsulated by poly (ethylene glycol) (PEG) in order to enhancing hydrophilicity, biocompatibility and immobilizing gold ions in the presence of NaBH4 as a reducing agent. Nanostructures were characterized again with FESEM and TEM. The nanoparticles with their spherical shape and dimensions of approximately 12 nm were used as a heterogeneous catalyst for Suzuki coupling reactions whilst in mild conditions. The high efficiency of the catalytic reaction was affirmed by the good yields of products, easy work-up, and absence of leached gold from the support and the smooth recovery of the catalyst.

In present study, the thermal conductivity of silver/water nanofluid was investigated experimentally. Four different volume concentrations of nanofluids (2, 3, 5 and 10%) were prepared by dispersing silver nanoparticles in water. The properties of nanofluids were measured by varying the temperature from 20ºC to 100ºC and also, different sizes of nanoparticles dispersed in water (20-30, 50-60 and 100-110 nm). The obtained results demonstrate that the thermal conductivity of nanofluids is the function of volume concentration, nanoparticles size and temperature. In addition, the impact of nanoparticles on the viscosity of the fluid was studied at different concentrations.

The Graphene based single electron transistor (SET) as a coulomb blockade device need to be explored .It is a unique device for high-speed operation in a nano scale regime. A single electron transfers via the coulomb barriers, but its movement may be prevented by coulomb blockade, so its effect is investigated in this research. The conditions of coulomb blockade and its controlling factors such as material, temperature, gate voltage and island length are investigated. At first, the coulomb blockade on fullerene SET as a nano transistor with new material is modeled and compared with experimental data of silicon SET. The comparison study indicates that the coulomb blockade range of fullerene SET is lower than the silicon one. On the other hand, the analysis demonstrates that, temperature and gate voltage play direct associations with zero current SET. In addition, island length and its material effect on coulomb blockade and desired current are achieved by decreasing the coulomb blockade range.

One plant seed extract (Psidium guajava) was screened for their bioreduction behavior for synthesis of silver nanoparticles. Psidium guajava (PG) was found to exhibit the good reducing and protecting action in terms of synthesis rate and monodispersity of the prepared silver nanoparticles. UV–visible spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and X-ray energy dispersive spectrophotometer (EDAX) was performed to ascertain the formation of Ag-NPs. Our measurements indicate that biosynthesis of Ag nanoparticles by Psidium guajava (PG) produces Ag nanoparticles with the diameters in the range of 30-36 nm. XRD studies reveal a high degree of crystallinity and monophasic Ag nanoparticles of facecentered cubic (FCC) structure. The FTIR result clearly showed that the extracts containing OH as a functional group act in capping the nanoparticles synthesis. Antibacterial activities of Ag-NPs were tested against the growth of Gram-positive (S. aureus) using SEM. The inhibition was observed in the Ag-NPs against S. aureus. The results suggest that the synthesized Ag-NPs act as an effective antibacterial agent. It is confirmed that Ag-NPs are capable of rendering high antibacterial efficacy and hence has a great potential in the preparation of drugs used againstbacterial diseases.

Polyacrylic acid/ octavinyl polyhedral oligomeric silsesquioxane, nanocomposite hydrogel with 3-D network was synthesized via radical polymerization. Octavinyl polyhedral oligomeric silsesquioxane was used as crosslinker and nanofiller simultaneously in the preparation of the hydrogel. Hydrogel adsorption performance was determined by adsorption of methylene blue. The adsorption capacity was evaluated under the effects of dye concentration, adsorption contact time and medium pH. The experimental data fitted a pseudo-second-order model and isotherm indicated that the data were agreed with the Langmuir model. The high adsorption capacity (Qmax=1000 (mg/g)) shows the better efficiency of the adsorbent and indicates this hydrogel is a good candidate as the adsorbent of cationic dye and ions.

Electrochemical behaviour of acetaminophen at the multi wall carbon nanotubes/titanium dioxide (MWCNT/TiO2) composite film modified glassy carbon electrode (GCE) via solvent casting method was studied. It is shown that the MWCNT/TiO2/GCE exhibits remarkable improvement in analytical response as compared to other electrodes. Comparing the responses of the MWCNT/TiO2/GCE with that obtained at the unmodified glassy carbon electrode, the peak currents were enhanced significantly by 8.5 folds (oxidation peak) and 11.0 folds (reduction peak), which showed stable response with enhanced selectivity and sensitivity. A linear calibration plot having a correlation coefficient of 0.991 was obtained in the concentration range of 0.01-0.12 mM acetaminophen. The detection limit for the detection of acetaminophen was calculated as 11.77 μM based on 3 σ/m. The method was applied in the determination of acetaminophen in commercial tablets. The recoveries of the composite modified electrode obtained were 95.2 and 96.2% for five determinations.

In order to produce biodiesel from waste cooking oil and optimize its yield, a two-stage process of esterification/ transesterification has been used in this study. First, we used the acidic catalysts H2SO4 in order to diminish the content of free fatty acid (FFA) in oil that caused reducing the oil acidity from 6.1% to 0.57% through esterification. Then, the biodiesel was produced by transesterification of resulted oil using heterogeneous CaO nanoparticles as catalyst. At each stage, the best possible conditions have been determined by applying Taguchi methodology for each major variable, including time, temperature, alcohol/oil molar ratio, and the amount of catalyst. The optimum conditions for esterification are achieved at 80°C temperature, 120 minutes time, 6:1 molar ratio of alcohol/oil, and H2SO4 content of 1% (w/w oil). The optimum condition for transesterification were found in 100 °C temperature, 90 minutes time, 8:1 molar ratio of alcohol/oil, and 3% (w/w oil) of CaO nanoparticles as catalyst. After applying full optimization of these two stages, the yield of the produced biodiesel has achieved 96.4%.

Extensive urbanization has greatly raised the demand for cleaner coal- and petroleum-derived fuels. Mainly composed of methane, natural gas represents a promising alternative for this purpose, making its storage a significant topic. In the present research, deposition of methane molecules in C60 fullerene was investigated through a combined approach wherein density functional based tight binding (DFTB) method was used to optimize the geometry while ab initio density functional theory (DFT) served as a tool for energy calculation. Doping endohedral methane molecules onto fullerene nanocage, it was witnessed that, the only stable complex might be formed by a single methane molecule entrapped inside the C60 cage. It was further indicated that, when a large number of encapsulated CH4 molecules are concerned, occasional chemisorption of the molecules on the inner surface of the cage would occur, ending up breaking the capsule side wall at NCH4=7. Further studied by density-functional tight-binding molecular dynamics (DFTB-MD) simulation, mechanism of the breakage indicated this complex as being highly unlikely to be stable.

The adsorption of the H2S molecule on the undoped and N-doped TiO2 anatase supported Au nanoparticles were studied using density functional theory calculations. The adsorption of H2S on both Au and TiO2 sides of the nanoparticle was examined. On the TiO2 side, the fivefold coordinated titanium site was found to be the most favorable binding site, giving rise to the strong interaction of H2S with TiO2 supported Au overlayer. It was found that the central sulfur atom of the H2S molecule preferentially binds to the fivefold coordinated titanium sites via formation of strong chemical bonds. By substituting nitrogen atom into the oxygen vacancy of TiO2, significant changes in the bond lengths, bond angles and adsorption energies of the complex systems occur. The adsorption of H2S on the N-doped TiO2-supported Au nanoparticle is more favorable in energy than the adsorption on the pristine one, indicating the strong interaction of H2S with N-dopedTiO2-supported Au. Thus, the N-doped nanoparticle can be utilized as potentially efficient H2S gas detection device. The substantial overlaps between the projected density of states of the titanium and sulfur atoms indicate, the formation of a chemical bond between the nanoparticle and H2S molecule. This work not only proposes a theoretical basis for gas sensing behaviors of TiO2- supported Au overlayers, but also provides an effective strategy for the development of innovative sensor devices for H2S recognition in the environment.