Solid State Phenomena Vol. 290

Abstract: The material with NASICON-type structure, lithium aluminum titanium phosphate with vanadium substituting phosphorous (Li_1.4Ti_1.6Al_0.4(PO₄)_2.9(VO₄)_0.1) (LATPV) has been synthesized via solid state method. The X-ray powder diffraction analysis shows the effect of vanadium in the composition LATPV. Various secondary phases have been observed due to vanadium substitution which leads to low ionic conductivity of σ = 2.5 x 10^-5 (Ωm)^-1. The thermal analysis indicated that the reaction of chemical mixture become stable at round 460 °C which indicated an improvement in the material densification.

Abstract: AuNPs were prepared by using a sacrificial hydrothermal method on Aluminum (Al) /(polymethylsilsesquioxane) PMSSQ / (Silicon) Si substrate. The Al layer was the sacrificial template dissolved in precursor during hydrothermal reaction. The effect of deposition method for Al template on AuNP formation was investigated. Two deposition methods (sputtering and thermal evaporation) of Al template were varied for preparing template. The properties of formed AuNPs were studied using field-emission scanning electron microscopy and X-ray diffractometer. PMSSQ was spin-coated on the produced AuNPs in order to investigate the memory properties, which were then characterized by using a semiconductor characterization system. The sample grown hydrothermally on sputtered Al template exhibited excellent memory properties with the lowest turn “ON” voltage at 2.4 V in I-V characteristics and 34 charges were stored per AuNP in C-V measurement. Therefore, isolate and uniform of AuNPs distribution are crucial for excellent memory properties of devices.

Abstract: Nowadays, gold nanoparticles (AuNPs) received a great deal of attention for biomedical applications especially in diagnostic imaging and therapeutics. In this study, we elucidate on how size of gold nanoparticles (AuNPs) affect cellular uptake. The size dependence of AuNPs cytotoxicity in MCF-7 cells was tested by using the WST-1 assay. The sizes of AuNPs tested were 13 nm, 50 nm, and 70 nm. The toxicity of AuNPs in MCF-7 cell lines was quantified by determining the IC₅₀ values in WST-1 assays. The IC₅₀ values (inhibitory concentrations that affected 50% growth inhibition) of 13 nm AuNPs is higher than 50 nm and 70 nm AuNPs. Mean that, 13 nm AuNPs is less toxic to MCF-7 cells. This cytotoxicity results generally agree with those obtained in the study of cellular uptake by Inverted Microscope and EFTEM. Morphological observation of MCF-7 after being treated with 13 nm, 50 nm, and 70 nm AuNPs, were looking unhealthy and dying out of the populace, the observed cells were more reduced and dying as treatment with 50 nm and 70 nm AuNPs. Cells detachment, clumping, shrunken, and dispersed cells in the culture medium and floating cells were also observed. The observed morphological changes increase in 50 nm and 70 nm AuNPs than in 13 nm AuNPs, which is less toxic to MCF-7 cells. The presented morphological analysis has also established that 13 nm AuNPs showed less toxic to MCF-7 cells. The presented results clearly indicate that the cytotoxicity and cellular uptake of AuNPs depend on the size of the nanoparticles.

Abstract: Radiation therapy and chemotherapy remain the most widely used treatment options in treating cancer. Recent developments in cancer research show that therapy combined with high-atomic number materials such as gold nanoparticles (AuNPs) is a new way to treat cancer, in which AuNPs are injected through intravenous administration and bound to tumor sites has enhanced tumor cell killing. Radiation therapy aims to deliver a high therapeutic dose of ionizing radiation to the tumor without exceeding normal tissue tolerance. In this work AuNPs have been used for the enhancement of radiation effects on breast cancer cells (MCF-7) for superficial kilovoltage X-ray radiation therapy. The use of AuNPs in superficial kilovoltage X-ray beams radiation therapy will provide a high probability for photon interaction by photoelectric effect. These provide advantages in terms of radiation dose enhancement. In this work, MCF-7 cells were seeded in the 96-well plate and treated with 13 nm, 50 nm and 70 nm AuNPs before they were irradiated with 80 kVp X-rays beam at various radiation doses. Photoelectric effect is the dominant process of interaction of 80 kVp X-rays with AuNPs. When the AuNPs are internalized into the MCF-7 cells, the dose enhancement effect is observed. The presence of AuNPs in the MCF-7 cells will produce a higher number of photoelectrons, and resulting more “free radicals” that will lead to increase in cell death. Then, these free radicals will lead to DNA damage to the MCF-7 cells. To validate the enhanced killing effect, both with and without AuNPs MCF-7 cells is irradiated simultaneously. By comparison, the results show that AuNPs significantly enhance cancer killing and the enhancement radiation effect was dependent on the size of AuNPs.

Abstract: A simple method to synthesized nanoparticles was satisfied by reduction of tetrachloroauric acid in the presence of palm oil fronds extracts as capping and reduced agents. The as-synthesized gold nanoparticles structures have a triangular and hexagonal shape that are of tens of nanometre in size. It was realized that good control shape of nano-hexagonal gold nanoparticles were obtained from nano-triangular gold nanoparticles in the absence of any soft template. The production techniques of the gold nanoparticles were examined by using UV-vis spectroscopy, EFTEM and XRD patterns, which showed peaks at (111), (200), (220), (311) and (222), that described the preferential structure of the AuNPs as face-centered cubic crystal

Abstract: Silver nanoparticles (Ag NPs) are embedded in Er³⁺/Nd³⁺ co-doped lithium niobate tellurite glasses of the form (68-x)TeO₂-15Li₂CO₃-15Nb₂O₅-1Er₂O₃-1Nd₂O₃-(x)AgCl with x = 1,2 and 3 mol% via conventional melt-quenching technique. The ultrasonic attenuation shows the rate of sound energy reduction when an ultrasonic wave is propagating in a medium which is the lithium niobate tellurite glasses. The glass attenuation depends on the grain size, viscous friction, crystal structure, porosity and hardness. The existence of Ag NPs with an average size of 3.7 nm is confirmed using TEM analysis.

Abstract: Graphene has gained tremendous attention due to its unlimited potential in various applications while poly(lactic acid) (PLA) is a biodegradable thermoplastic polyester produced from fermenting corn starch. The incorporation of graphene into PLA has been proven to exhibit excellent mechanical and thermal properties. However, there are not many reports on the potential toxic effect of these materials towards living organisms. In this study, we investigated the possible toxicity of graphene and PLA-graphene in a live animal model, the nematode Caenorhabdits elegans (C. elegans). Alive adult worms were exposed directly to graphene and PLA-graphene across a range of concentrations from 50 µg/mL to 1000 µg/mL. After certain hours of exposure, the pharyngeal pumping rate (indicative of the C. elegans feeding activity), reproductive rate and lifespan of the worms were determined and compared to the untreated worm population. At all concentrations tested, both graphene and PLA-graphene do not affect the feeding rate of the nematode. Additionally, there was no significant difference between the lifespan of worms exposed to graphene and PLA-graphene as compared to the untreated control population (p>0.05). We examined the effect of graphene on nematode’s ability to reproduce and no reduction in progenies was detected (p>0.05). Taken together, our findings suggest that graphene and PLA-graphene do not possess a negative effect on the feeding activity, reproduction and overall lifespan of the host, indicating that these materials are safe to living organism at concentration up to 1000 µg/mL.

Abstract: Studying an influence of several parameters on Chemical Vapor Deposition (CVD) used for graphene synthesis is crucial to optimizing the graphene quality to be Compatible with advanced devices. The effect of different hydrogen (H₂) flow-rates (0, 50, 100, 150, 200, 250, and 300 sccm) during the pre-annealing process on CVD grown graphene have been reported. This study revealed that hydrogen flow rates during annealing changed the surface roughness/smoothness of the copper substrates. For high hydrogen flow rates, the smoothing effect was increased. Furthermore, the annealed graphene samples emerged a deferent number of layers because of morphological surface changes. According to Raman D- to G-band intensity ratios (I_D/I_G), the graphene quality was influenced by the annealing hydrogen flowrate. The visible light transmittance values of the grown graphene samples confirmed a few number of layers (mono to seven-layer). Mostly, the samples which annealed under moderate hydrogen flow rates showed less defects intensities and higher crystallite sizes.

Abstract: A floating catalyst CVD system was utilized to synthesis CNT film. The morphological of the synthesized CNT film was characterized using field emission scanning electron microscope (FESEM) and high resolution transmission electron microscope (HRTEM). While, graphitization and crystallinity of CNT film was determined by thermogravimetric analysis and Raman spectroscopy. The injection rate of carbon source was the main variable parameter in this work shown great contribution influencing morphological structure of materials. A suitable optimization parametric study of injection rate was determined. This work shows an overview of synthesis CNT film using floating catalyst and the effect of injection carbon source solution on properties of CNT film which is useful for future work.

Abstract: The influence of graphite grinding time on the formation of carbon nanotubes (CNTs), is investigated. Graphite with different grinding time is used for the growth of CNTs by a cost-effective method using a microwave oven. The samples produced using the different grinding time contain nanotubes with an average diameter in the range 31–50 nm as observed by field emission scanning electron microscopy (FESEM). The lowest intensity ratio of D and G bands (ID/IG) and full width at half maximum of G as identified by Raman spectroscopy for grinding time 20 minute indicates the improved crystallinity of CNTs.