Nanoscience & Nanotechnology-Asia - Volume 4, Issue 2, 2014

Iron chelating drugs can impede the rapid reproduction of tumor cells. Among these drugs, deferasirox (DEF) have shown antitumor properties and therefore been selected for this study. The aim of this study was preparation and characterization of the bifunctional polymeric nanoparticles (NPs) by targeting moieties which is applied in cancer. Therefore, DEF NPs were fabricated by exploiting of PLGA-PEG-FOL conjugate and combination of sonication and emulsification/solvent evaporation technique. Then the influence of important factors including the amount of vitamin E TPGS as a safe surfactant and the ratio of drug to polymer in organic phase was evaluated. Some formulations showed suitable size distribution below 200 nm with high drug entrapment. Drug release study indicated sustained release profile of DEF encapsulated in NPs. Stability study showed acceptable condition for preserving the formulation during six months.

In this study, Fe doped barium aluminate nano powder has been synthesized via homogeneous precipitation method and was investigated for its activity on the epoxidation chalcone with hydrogen peroxide as a pure oxidant. The obtained samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and Energy-dispersive X-ray spectroscopy (EDAX). The average particle size of the powder was determined to be 37 nm by FE-SEM.

Urea intercalated layered material nanohybrid formulations based on two types of layered clays, layered double hydroxides and montmorillonite were developed for agricultural applications as slow release nitrogen plant nutrient formulations. The resulting nanohybrids were prepared by the intercalation of urea between the nanolayers of clay matrixes. The successful intercalation of the guest urea molecule was confirmed using the number of solid state characterization techniques and the possible structure of urea between the layers was deduced. Urea molecules are expected to be bound through their carbonyl and amine modes to the nanolayers of the clay with several interaction modes of different bond strengths. Thus, electrostatic interactions between urea and the nanoclay layers would reduce the rate of hydrolysis of urea and decomposition into gaseous products. Release behavior of urea of nanohybrids was studied in water and compared with that of pure urea. Both nanohybrid formulations displayed significant degree of slow release behavior.

In this study, sulfonated poly ethylene terephthalate (SPET) nonwoven membrane for heavy metal ion filtration was prepared by electrospining with different conditions and then simulated by wastewater containing metal ion as an aqueous solution. Commonly used for the exclusion of metal ions from wastewater, the ionic interaction between negatively charged matrices and positively charged metal ions has been utilized. The controllable factors i.e., initial concentration, adsorbent amount, pH, and pressure on the efficiency of filtration were optimized in this study. The results showed that the metal ion rejection increased with increasing adsorbent concentration and the pH of solution, while it was decreased by increasing applied pressure and concentration of solution. PH solution was found to be the most effective in the efficiency of metal removal and then adsorbent concentration, initial concentration of metal ion and pressure were affected, respectively. Spectra ATR–FTIR of the samples before and after filtering membrane translocation showed absorption bands, indicating that absroption mainly occurred through the reaction between the metal ion and the polyester sulfonated group. The pollutant removal efficiency (PRE) under optimum conditions was obtained to be 99.7%, 99.32%, and 86.37% for Cu(II), Pb(II) and Zn(II), respectively. The filtration mechanism was determined through blocking law and an acceptable agreement was achieved for internal pore blocking mechanism. Langmuir and Freundlich, which are two equilibrium adsorption isotherms, were fitted to the data. The best fit was related to the Freundlich model in comparison with Langmuir model. By using Freundlich model, the relative adsorption capacity was obtained 595.26, 534.85 and 154.00 mg/g for Cu(II), Pb(II) and Zn(II), respectively.

In this study the effect of annealing at 400oC and gamma irradiation at 30 kGy doses with the rate of 2.4 Gy/s as post treatments on optical properties and dimension of Ag nanoclusters was investigated. Ag nanoclusters were formed by ion-exchange process during which SLS substrates immersed in to the AgNO3 salt bath at 400°C. Grazing incidence x-ray diffraction analysis demonstrated the presence of Ag on Ag-ion exchanged substrates. The ion-exchanged substrates were then annealed and gamma irradiated as post treatments. The effect of post treatments on optical properties of samples including absorption spectra and linear refractive index, was examined by analyzing optical density as a function of wavelength curves and Brewster angle determination. The results of absorption spectra indicated broadening and shift of ionic (Ag⁺N), and neutral (Ag⁰N) silver nanocluster peaks after post treatments. Peak displacement as blue shift in annealed and red shift in gamma irradiated samples was revealed. Calculation of Ag nanocluster dimensions and refractive index of substrates revealed that post treatment procedures and especially gamma irradiation process caused non linear reduction in both of their values. However, the linear refractive index of of ion-exchanged and subsequently post treatments caused increase of linear refractive index of SLS substrate (n⋍1.5).

Ab initio calculations of ZnO nanowires (NW) were performed using density functional theory within LDA-1/2, to account for the excited states energies. The effects of hydrogenpassivated and non-passivated nanowires in a range of diameters were studied. For passivated cases it was obtained a band gap of 5.5 eV for the thinnest wire (∼0.6 nm thick) and 4.0 eV for the thickest NW (∼1.6 nm) (and similar to bulk for the non-passivated). The LDA confinement was found to be superestimated if compared to LDA-1/2, which also predicts experimental band gaps of ZnO nanowires with excellent precision.

Engineered nanomaterials in the 21^st century have revolutionized all dimensions of life and Titanium di oxide nanoparticles are one such important materials, which are being increasingly used for a variety of clinical, cosmoceutical, pharmaceutical, optical and other commercial applications. Their versatile applications are mainly due to the large surface-to-volume ratio and unique physico-chemical, mechanical and electrical properties. Employing them in varied fields has no doubt proved to be beneficial, but on the other side are the toxicity concerns. Extensive use has lead to their considerable accumulation in the environment causing ecological imbalance and upsetting the normal flora and fauna residing therein. It is therefore very vital to heed to the recent alerts sounded on their toxic biological effects on the ecosystem and food chains. Further, the effect of these particles of live cells and tissues, both short and long term, also remains to be studied and validated. These wonder particles are too valuable to be discarded, even if deleterious and hence, the balancing of their benign and hazardous effects may be need of the hour. In this paper, the viable synthetic methods available today for their preparation, both chemical and biological routes are reviewed, along with their versatile applications. Further, the emerging mechanisms for elucidating their toxicity and possible means for their remediation are also discussed.