Salman A. H. Alrokayan

Comparative evaluation of immunohistochemistry and real-time PCR for measuring proinflammatory cytokines gene expression in livers of rats treated with gold nanoparticles.

Gold nanoparticles (GNPs) possess promising applications in targeted drug delivery and controlled release of a variety of chemical agents. However, the immunocompatibility of GNPs is poorly understood. After exposure, GNPs preferentially tend to accumulate is liver, where they induce an acute phase proinflammatory response. We therefore compared the two techniques, immunohistochemistry and real-time PCR for measuring the protein and mRNA expressions of IL-1β, IL-6 and TNF-α in liver of rats after intraperitoneal injections (5μg/animal) of 10 and 50nm diameter GNPs for 1 and 5days. The results showed that both 10nm and 50nm GNPs induced an acute phase expression of proinflammatory cytokines that receded on day 5. The proinflammatory response on day 1 was comparatively more severe with 50nm GNPs than 10nm GNPs. A comparative evaluation between immunostaining and real-time PCR showed that the latter technique is more sensitive as it could detect the cytokines mRNA expression in control samples as well. This could be partly attributed to the amplification strategy used in real-time PCR and partly to the variations in the half lives of cytokines mRNA and their resulting proteins.

The effect of synthesis time on graphene growth from palm oil as green carbon precursor

Graphene is the new material that arises after carbon nanotubes (CNTs) era and has extraordinary optical, electronic and mechanical properties compared to CNTs. The 2D graphene is the sp2 carbon allotropes compared to other dimensionality. It also can be in three forms that are zero-dimensional, one-dimensional or three-dimensional. The different dimensionality also called fullerenes, nanotubes and graphite. Therefore, the graphene is known as centre potential materials in expanding research area than others ever. The 2cm × 2cm silicon wafer was seeded with nickel (Ni) at different thickness by using sputter coater. The palm oil, carbon source, was placed in the precursor furnace and the silicon was placed in the second furnace (deposition furnace). The palm oil will mix with Nitrogen gas was used as carrier gas in the CVD under certain temperature and pressure to undergo pyrolysis proses. The deposition temperature was set at 1000 °C. The deposition time varied from 3 minutes, 5 minutes and 7 minutes. Th...

Immunostaining of proinflammatory cytokines in renal cortex and medulla of rats exposed to gold nanoparticles

Recently, gold nanoparticles (GNPs) have shown promising applications in targeted drug delivery and contrast imaging. Although in vitro cytotoxicity of GNPs has been thoroughly studied, there are limited data on in vivo toxicity of GNPs. In this study, we evaluated the effects of intraperitoneally injected 10 nm and 50 nm GNPs (5 μg/animal) on the expression of proinflammatory cytokines (IL-1β, IL-6 and TNF-α) on day 1 and day 5, post-exposure. The results of immunohistochemistry showed that both 10 nm and 50 nm GNPs induced an acute phase expression of proinflammatory cytokines in renal cortex and medulla. This proinflammatory response was comparatively more intense in renal medulla than cortex. All the three cytokines were undetectable in control cortex and medulla. In conclusion, both 10 nm and 50 nm GNPs caused an acute phase induction of proinflammatory cytokines in cortex and medulla of rat kidneys. An intense immunostaining of proinflammatory cytokines in renal medulla warrants further studies to evaluate the nephrotoxicity of GNPs to validate the safe application of GNPs for contrast imaging in renal insufficiency.

Size and time-dependent induction of proinflammatory cytokines expression in brains of mice treated with gold nanoparticles

Gold nanoparticles (GNPs) are among the ideal nano-sized materials for medical applications such as imaging and drug delivery. Considering the significance of recent reports on acute phase induction of inflammatory mediators by GNPs, we studied the effect of GNPs on proinflammatory cytokines gene expression in mouse brain. Group 1 served as control whereas groups 2–4 were given only one intraperitoneal dose of 5, 20 and 50 nm GNPs, respectively and sacrificed after 24 h. The animals in groups 5–7 also received the same treatment but sacrificed after 7 days. Groups 8–10 received two injections of GNPs (5, 20 and 50 nm, respectively), first at the beginning of study and second on day 6, and sacrificed on day 7. Total RNA was extracted from the cerebral tissue and analyzed for the gene expressions of IL-1β, IL-6 and TNF-α. A single injection of 5 nm diameter GNPs significantly increased the mRNA expression of IL-1β and IL-6 in mouse brain on day 7, which was not augmented by the second dose of the same GNPs. Larger size GNPs (20 nm and 50 nm) did not cause any significant change in the expression of proinflammatory cytokines in mouse brain. In conclusion, systemic administration of small sized GNPs (5 nm) induced a proinflammatory cascade in mouse brain indicating a crucial role of GNPs size on immune response. It is important to use the right sized GNPs in order to avoid an acute phase inflammatory response that could be cytotoxic or interfere with the bioavailability of nanomaterials.

Structural properties of ZnO nano-template layer by spin coating method

Zinc oxide (ZnO) nano-template layer was prepared using spin coating method. The coating layer was varied from 1 to 9 layers in this study. The surface morphology was observed by field emission scanning microscopy (FESEM). Meanwhile, the roughness and total grain boundary were characterised by atomic force microscopy (AFM). The thickness was increased from 90-310 nm, when the coating layer was increased. The grain size was observed below 50 nm. The surface roughness and its total grain boundary was increased and decreased, respectively.Zinc oxide (ZnO) nano-template layer was prepared using spin coating method. The coating layer was varied from 1 to 9 layers in this study. The surface morphology was observed by field emission scanning microscopy (FESEM). Meanwhile, the roughness and total grain boundary were characterised by atomic force microscopy (AFM). The thickness was increased from 90-310 nm, when the coating layer was increased. The grain size was observed below 50 nm. The surface roughness and its total grain boundary was increased and decreased, respectively.

Structural and electrical properties of nanostructured ZnO

Nanostructured zinc oxide (ZnO) thin film was deposited using immersion method. The molarity was varied in range of 0.02 to 0.10 M in this study. The surface morphology was observed by field emission scanning microscopy (FESEM). Meanwhile, the roughness were characterised by atomic force microscopy (AFM). The current-voltage (I-V) measurement was done to determine its electrical properties. Flake-like morphology was found to increase the electrical properties of nanostructured ZnO thin film. The uniformity was increased when the molarity was increased.Nanostructured zinc oxide (ZnO) thin film was deposited using immersion method. The molarity was varied in range of 0.02 to 0.10 M in this study. The surface morphology was observed by field emission scanning microscopy (FESEM). Meanwhile, the roughness were characterised by atomic force microscopy (AFM). The current-voltage (I-V) measurement was done to determine its electrical properties. Flake-like morphology was found to increase the electrical properties of nanostructured ZnO thin film. The uniformity was increased when the molarity was increased.

Effect of solution concentration on MEH-PPV thin films

MEH-PPV thin films were prepared with a mixture of THF (tetrahydrofuran) solution deposited by spin coating method. The surface topology of MEH-PPV thin film were characterize by atomic force microscopy (AFM) and optical properties of absorption spectra were characterized by using Ultraviolet-visible-near-infrared (UV-Vis-NIR). The MEH-PPV concentration variation affects the surface and optical properties of the thin film where 0.5 mg/ml MEH-PPV concentration have a good surface topology provided the same film also gives the highest absorption coefficient were then deposited to a TiO2 thin film forming composite layer. The composite layer then shows low current flow of short circuit current of Isc = -5.313E-7 A.MEH-PPV thin films were prepared with a mixture of THF (tetrahydrofuran) solution deposited by spin coating method. The surface topology of MEH-PPV thin film were characterize by atomic force microscopy (AFM) and optical properties of absorption spectra were characterized by using Ultraviolet-visible-near-infrared (UV-Vis-NIR). The MEH-PPV concentration variation affects the surface and optical properties of the thin film where 0.5 mg/ml MEH-PPV concentration have a good surface topology provided the same film also gives the highest absorption coefficient were then deposited to a TiO2 thin film forming composite layer. The composite layer then shows low current flow of short circuit current of Isc = -5.313E-7 A.

Surface morphology and molecular bonding of CaCO3 nanocrystallites by gas diffusion method

Calcium carbonate with the chemical formula of (CaCO3) is the most abundant element in the world. Its usage on certain applications is largely affected by its properties. The best means to control its properties is through controlled preparation of CaCO3. This study uses diffusion method between the precursors Calcium Chloride and Ammonium Carbonate. Instead of using water, ethanol was used to prepare the salt. Reaction was done in room temperature (RT) for 6h-24h. Smallest average crystallite size measured by FESEM micrograph is 500nm produced by synthesis of CaCO3 reacted for 168 hours. From energy-dispersive X-ray spectrum also indicated the smallest particle size is by CaCO3 reacted for 168 hours. Changes was seen for element Ca at 3.7keV.Calcium carbonate with the chemical formula of (CaCO3) is the most abundant element in the world. Its usage on certain applications is largely affected by its properties. The best means to control its properties is through controlled preparation of CaCO3. This study uses diffusion method between the precursors Calcium Chloride and Ammonium Carbonate. Instead of using water, ethanol was used to prepare the salt. Reaction was done in room temperature (RT) for 6h-24h. Smallest average crystallite size measured by FESEM micrograph is 500nm produced by synthesis of CaCO3 reacted for 168 hours. From energy-dispersive X-ray spectrum also indicated the smallest particle size is by CaCO3 reacted for 168 hours. Changes was seen for element Ca at 3.7keV.

High crystallinity property of bilayer composited PbTiO 3 /PVDF-TrFE nanodielectric film capacitor

Innovative advance dielectric materials were utilized to fabricate novel thin film capacitor device. This includes ceramic and polymeric material combination which is considered to enhance the dielectric polarization. The dielectric film presented in the study focused on PbTiO3/PVDF-TrFE which was prepared through layer-by-layer spin coating deposition method. The PVDF-TrFE coating was aimed to encapsulate the fragility and to improve the crystallinity property of PbTiO3 thin film surface. The preferential orientation of (1 0 1) tetragonal perovskite PbTiO3 was obtained in this and high crystallinity was found on bilayered PbTiO3/PVDF-TrFE film. The bilayered film produced good film surface in term of its uniformity and surface roughness. The εr and tan (δ) value of bilayered PbTiO3/ PVDF-TrFE film was taken at 1 kHz that approximately 220 and 0.09 respectively.

Preparation of PVDF-TrFE layer-based bilayer composite PbTiO3/PVDF-TrFE films for MIM capacitor

The capacitor device has evolved from a simple device to an innovative and complex device. The capability of a capacitor is very much dependent on capacitance performance. Currently, researchers have shown interest in hybrid composites, which are capable of improving performance and increase reliability of devices. Thus, there is a need to fabricate thin films of hybrid dielectric materials such as polymer (PVDF-TrFE) and ceramic (PbTiO3). This study presents the preparation of the PVDF-TrFE layer for bilayer composite PbTiO3/PVDF-TrFE configured as metal–insulator–metal films capacitor. The deposition process utilised two methods: solvent casting and spin coating. The ceramic layer (first layer), PbTiO3, has optimum dielectric permittivity and tangent loss of about 138 and 0.9 taken at 1 kHz. The polymeric spin-coated layer (second layer) PVDF-TrFE films produced good dielectric property as compared to solvent casting prepared films. This provides an opportunity for further investigation of the dielectric property for enhanced understanding of capacitor-based devices.