Current Nanoscience - Volume 10, Issue 2, 2014

The aim of present investigation was to develop and evaluate cholesterol-rich nanoemulsions (LDE) of cholesteryl-succinyl-5- fluorouracil (CS-5-FU conjugate) in order to improve therapeutic efficacy and to reduce adverse effects of the treatment. LDE formulations of CS-5-FU conjugate were developed by high energy emulsification technique and developed formulations were physicochemically characterized for droplet size, polydispersity index, zeta potential, surface morphology and refractive index. In vitro drug release studies of CS-5FU conjugate from LDE nanoemulsions were performed using dialysis membrane. The droplet size (42.2 nm), polydispersity index (0.119), zeta potential (-29.65 mV), viscosity (35.22 cp) and refractive index (1.337) were found to be lowest for optimized formulation LDE5 (containing CS-5-FU-6 mg/cholesterol-0.5 mg/Triolein-1 mg/phosphatidylcholine-20 mg/cholesteryloleate-40 mg/Tween-80-0.3 ml/Labrasol-0.3 ml). Optimized formulation LDE5 also showed best drug release profile (98.4%) through dialysis membrane after 24 h of study. These preliminary studies indicated that developed LDE nanoemulsions could be applied for targeting of CS-5-FU conjugate to cancer cells.

Coenzyme Q10 (CoQ10) has been reported as a powerful antioxidant in plasma. Recent in vivo investigations showed that cosmetically applied CoQ10 can reduce photo-aging. However, CoQ10 was barely satisfactory in topical drug delivery because of its poor solubility and high molecular weight. To improve the anti-oxidative efficiency of CoQ10 in skin photo-aging, a novel water-soluble nanoscale solid dispersion of CoQ10 (CoQ10-SD) was prepared by heat melt and high-pressure homogenization method in the present study. Three sizes of CoQ10-SDs were obtained and characterized. The spectral investigations showed that the smaller particle size solution of CoQ10-SD was more effective against ultraviolet (UV) radiation. The UVB radiation absorption and reflection of the CoQ10-SD solution increased with increasing concentration and decreasing particle size. The in vitro antioxidants of CoQ10-SD were also assessed. The results showed that, smaller particle size results in higher antioxidant effect. A lower level of intracellular reactive oxygen species was found when the myocardial cells were treated with CoQ10-SD of smaller size. These findings indicated that CoQ10-SD can be an effective cosmetic delivery system to protect the skin from early aging induced by UV.

Self-assembled monolayer (SAM) as a unique type of nanomaterials has played important roles in modern nanotechnology. In this study, we described a novel method to fabricate SAM with a surfactant-like peptide A6K, which has been known to self-assemble into micellar nanofibers in aqueous solution. Firstly a simple filtration method was used to remove self-assembling nanofibers and retain peptide monomers in solution. Pyrene-fluorescence, dynamic light scattering (DLS) and atomic force microscopy (AFM) were used to confirm that nanofibers were effectively removed and filtered solution contained only peptide monomers. Then by incubating the filtered peptide solution on mica surface, the peptide monomers could self-assemble into a flat and continuous peptide SAM, which was further proved to be a suitable substrate for creating nanopatterns by AFM nanolithography.

A rapid synthesis route for the preparation of spherical cadmium sulfide (CdS) nanoparticles (NPs) was demonstrated by thermal decomposition of cadmium diethyldithiocarbamate(Cd[Ddtc]2) metal complex in the presence of a catalytic amount of hexadecylamine (HDA) using olive oil as the reaction medium. CdS nanoparticles were isolated and characterized by using HRTEM, FESEM, TGA, XRD, EDAX, PL, and Raman studies. The photocatalytic behaviour of the CdS nanoparticles was analyzed against the textile dye Congo red (CR). The degradation process follows the pseudo first order kinetics and the proposed method can be utilized for the efficient degradation of Congo red textile dye using UV light irradiation.

In this work, we have developed a facile but efficient method to prepare mushroom-like Zinc oxide (ZnO) nanostructures with a flat cap in the diameter of around 1μm, by thermal evaporation of the mixture of ZnS and carbon powder on a tungsten substrate. The mushroom-like nanostructures were characterized by using advanced techniques such as scanning electron microscope (SEM), X ray diffraction (XRD) and Raman spectroscopy. The optical properties of such product were also investigated by photoluminescence spectroscopy, revealing a strong green emission band emerged, which may be attributed to the oxygen vacancies and various surface states. Finally the formation and growth mechanisms for the mushroom-like ZnO nanostructures were proposed and discussed.

Barium doped ZnO nano-particles have been prepared via homogeneous precipitation method under ambient conditions using zinc chloride and barium chloride as starting materials and were found to be effective catalysts for the three-component condensation reaction of 2-aminobenzoic acid, triethyl orthoformate and aromatic amines. The structural features of the samples were assessed by X-ray diffraction (XRD), BET, field emission scanning electron microscopy (FE-SEM) and Energy-dispersive X-ray spectroscopy (EDAX). The average crystalline size estimated by using the Scherrer formula from the highest peak of the XRD was 85-86 nm for all samples. The results of BET are comparable with those obtained from XRD patterns. The change in the morphology and particle size of the as prepared composites was investigated. The particles are irregular in shape, mostly are spherical and some of them have hexagonal structure. The prepared nano-particles have been applied to the synthesis of a variety of quinazolin-4(3H)-ones. The products were isolated in high yields. In addition, the catalyst could be reused without any significant loss of its catalytic activity.

Dy+3 doped strontium ferrites Sr1-Dyx (ZnZr)0.5 Fe11O19 (x=0, 0.01, 0.02 and 0.03) were prepared by the citrate sol-gel method. The X-ray diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometry, and vector network analyzer were used for phase characterization and microwave absorption properties of obtained powders. X-ray diffraction identified that all samples were single phase with the M-type hexagonal-ferrite structure. The average crystallite size was about 48-62 nm. The microwave electromagnetic properties of the samples were studied at the frequency range from 12 GHz to 20 GHz. It was shown that small amounts of Dy+3 substitution could magically adjust to microwave electromagnetic parameters. The reflection loss indicates a minimum peak when ‘‘x=0.01’’, and the peak value was 41.0 dB. Also results indicate that a wide bandwidth of microwave absorption is obtained in the composite samples containing ferrite powders with composition ‘‘x=0.02’’ and ‘‘x=0.03’’ in Ku-band frequencies. It should be noted that thicknesses of the absorbers are only 1.7 mm.