Intercomparison of Radiosensitization Induced by Gold and Iron Oxide Nanoparticles in Human Glioblastoma Cells Irradiated by 6 MV Photons

In this work, an intercomparison of sensitization effects produced by gold (GNP) and dextran-coated iron oxide (SPION-DX) nanoparticles in M059J and U87 human glioblastoma cells was performed using 6MV-photons. Three variables were mapped: the nanoparticle material, treatment concentration, and cell radiosensitivity. For U87, GNP treatments resulted in high sensitization enhancement ratios (SER10% up to 2.04). More modest effects were induced by SPION-DX, but still significant reductions in survival were achieved (maximum SER10%=1.61). For the radiosensitive M059J, sensitization by both NPs was poor. SER10% increased with the degree of elemental uptake in the cells, but not necessarily with treatment concentration. For GNP, where exposure concentration and elemental uptake were found to be proportional, SER10% increased linearly with concentration in both cell lines. For SPION-DX, saturation of sensitization enhancement and metal uptake occurred at high exposures. Fold change in the α/β ratios extracted from survival curves are reduced by the presence of SPION-DX but strongly increased by GNPs, suggesting that sensitization by GNPs occurs mainly via promotion of lethal damage, while for SPION-DX repairable damage dominates. The NPs were more effective in eliminating the radioresistant glioblastoma cells, an interesting finding, as resistant cells are key targets to improve treatment outcome.

Effect of Surfactants and Nanoparticle Materials on the Stability and Properties of CuO-Water and Fe3O4-Water Nanofluids

The arguments in favor of using nanofluids in thermal applications have been increasing substantially for the last few decades. Nanofluids provide improved performance in heat transfer processes in comparison to their base fluids as a result of their superior thermal properties. Even though nanofluids exhibit better thermal properties, their usage has been limited due to their stability issues. The stability of the nanofluid greatly affects its thermal properties over a period of time. The stability and thermal properties of nanofluids can be affected by parameters like surfactants used and their concentrations, and also on the nanomaterial used in the nanofluid. In this study, surfactant material and nanoparticle material are selected as process variables and for each variable two levels are selected. For surfactant material, Sodium Lauryl Sulfate (SLS) and Cetyl Trimethyl Ammonium Bromide (CTAB) are selected. Surfactant concentration ratios are taken as 1:2 for CuO and 1:4 for Fe3O4 material. Four nanofluid samples are prepared with 0.1% weight of nanoparticles and their stability and properties are studied. The feasibility of turbidity as an indicator for stability is also explored in this work. The results show that the zeta potential and hydrodynamic characteristics are largely dependent on the surfactant material. Both surfactants show good stability of nanofluids. In-line with earlier observations, it is also observed that the nanoparticle material has a dominant effect on the thermal conductivity of the nanofluids. Comparing the turbidity of the nanofluids to the zeta potential, it is observed that the turbidity measurement gives first-hand information about the stability of nanofluids and can act as an index for stability. But still, more exploration is necessary for this field so a quantitive relation can be established between turbidity and zeta potential of different nanofluid materials and concentrations.

Key for crossing the BBB with nanoparticles: the rational design

Central nervous system diseases are a heavy burden on society and health care systems. Hence, the delivery of drugs to the brain has gained more and more interest. The brain is protected by the blood–brain barrier (BBB), a selective barrier formed by the endothelial cells of the cerebral microvessels, which at the same time acts as a bottleneck for drug delivery by preventing the vast majority of drugs to reach the brain. To overcome this obstacle, drugs can be loaded inside nanoparticles that can carry the drug through the BBB. However, not all particles are able to cross the BBB and a multitude of factors needs to be taken into account when developing a carrier system for this purpose. Depending on the chosen pathway to cross the BBB, nanoparticle material, size and surface properties such as functionalization and charge should be tailored to fit the specific route of BBB crossing.

Dose Enhancement for the Flattening-Filter-Free and Flattening-Filter Photon Beams in Nanoparticle-Enhanced Radiotherapy: A Monte Carlo Phantom Study

Monte Carlo simulations were used to predict the dose enhancement ratio (DER) using the flattening-filter-free (FFF) and flattening-filter (FF) photon beams in prostate nanoparticle-enhanced radiotherapy, with multiple variables such as nanoparticle material, nanoparticle concentration, prostate size, pelvic size, and photon beam energy. A phantom mimicking the patient’s pelvis with various prostate and pelvic sizes was used. Macroscopic Monte Carlo simulation using the EGSnrc code was used to predict the dose at the prostate or target using the 6 MV FFF, 6 MV FF, 10 MV FFF, and 10 MV FF photon beams produced by a Varian TrueBeam linear accelerator (Varian Medical System, Palo Alto, CA, USA). Nanoparticle materials of gold, platinum, iodine, silver, and iron oxide with concentration varying in the range of 3–40 mg/ml were used in simulations. Moreover, the prostate and pelvic size were varied from 2.5 to 5.5 cm and 20 to 30 cm, respectively. The DER was defined as the ratio of the target dose with nanoparticle addition to the target dose without nanoparticle addition in the simulation. From the Monte Carlo results of DER, the best nanoparticle material with the highest DER was gold, based on all the nanoparticle concentrations and photon beams. Smaller prostate size, smaller pelvic size, and a higher nanoparticle concentration showed better DER results. When comparing energies, the 6 MV beams always had the greater enhancement ratio. In addition, the FFF photon beams always had a better DER when compared to the FF beams. It is concluded that gold nanoparticles were the most effective material in nanoparticle-enhanced radiotherapy. Moreover, lower photon beam energy (6 MV), FFF photon beam, higher nanoparticle concentration, smaller pelvic size, and smaller prostate size would all increase the DER in prostate nanoparticle-enhanced radiotherapy.

Analisis Struktur Kristal Polyetilen Glicol (PEG-4000) Coated Nanopartikel Magnetite (Fe3O4)

The synthesis of materials made from FeSO4.7H2O, FeCl3.6H2O, and NH4OH hydrophilic materials has been carried out using coprecipitation method to produce Fe3O4 nanoparticle material. Analysis of the crystalline structure of Fe3O4 nanoparticles seen from the results of material characterization using X-Ray Diffractometer showed diffraction peaks namely (220) (311) (400) (511) (440) with the main peak at the index (311). Samples of Fe3O4 nanoparticles were modified with PEG-4000 polymer, emerging new diffraction peaks such as peaks with index (111), α- Fe3O4 peaks, γ-FeO (OH) peaks and α-FeO ​​(OH) peaks. The emergence of these new peaks is due to the influence of the PEG-4000 polymer which directly shows the bond with the -OH (hydroxyl) group.

Enhanced Light Extraction from Bottom Emission OLEDs by High Refractive Index Nanoparticle Scattering Layer

High refractive index nanoparticle material was applied as a scattering layer on the inner side of a glass substrate of a bottom emission organic light emitting diode (OLED) device to enhance light extraction and to improve angular color shift. TiO2 and YSZ (Yttria Stabilized Zirconia; Y2O3-ZrO2) were examined as the high refractive index nanoparticles. The nanoparticle material was formed as a scattering layer on a glass substrate by a coating method, which is generally used in the commercial display manufacturing process. Additionally, a planarization layer was coated on the scattering layer with the same method. The implemented nanoparticle material and planarization material endured, without deformation, the subsequent thermal annealing process, which was carried out at temperature ranged to 580 °C. We demonstrated a practical and highly efficient OLED device using the conventional display manufacturing process by implementing the YSZ nanoparticle. We obtained a 38% enhanced luminance of the OLED device and a decreased angular color change compared to a conventional OLED device.