Erdal Sönmez

Evaluation of cytotoxic, oxidative stress and genotoxic responses of hydroxyapatite nanoparticles on human blood cells

The present study was designed to investigate genotoxic and cytotoxic effects and oxidative damage of increasing concentrations of nano‐hydroxyapatite (5, 10, 20, 50, 75, 100, 150, 300, 500 and 1000 ppm) in primary human blood cell cultures. Cell viability was detected by [3‐(4,5‐dimethyl‐thiazol‐2‐yl) 2,5‐diphenyltetrazolium bromide] assay and lactate dehydrogenase release, while total antioxidant capacity and total oxidative stress levels were determined to evaluate the oxidative injury. The DNA damage was also analyzed by sister chromatid exchange, micronuclei, chromosome aberration assays and 8‐oxo‐2‐deoxyguanosine level as indicators of genotoxicity. The results of [3‐(4,5‐dimethyl‐thiazol‐2‐yl) 2,5‐diphenyltetrazolium bromide] and lactate dehydrogenase assays showed that the higher concentrations (150, 300, 500 and 1000 ppm) of hydroxyapatite nanoparticles (HAP NPs) decreased cell viability. HAP NPs led to increases of total oxidative stress (300, 500 and 1000 ppm) levels and decreased total antioxidant capacity (150, 300, 500 and 1000 ppm) levels in cultured human blood cells. On the basis of increasing concentrations, HAP NPs caused significant increases of sister chromatid exchange, micronuclei, chromosome aberration rates and 8‐oxo‐2‐deoxyguanosine levels as compared to untreated culture. In conclusion, the obtained in vitro results showed that HAP NPs had dose‐dependent effects on inducing oxidative damage, genotoxicity and cytotoxicity in human blood cells. Copyright

The Risk Evaluation of Tungsten Oxide Nanoparticles in Cultured Rat Liver Cells for Its Safe Applications in Nanotechnology

Tungsten (VI) oxide (WO3) nanoparticles (NPs) are used for many industrial purposes in everyday life. However, their effects on human health have not been sufficiently evaluated. Therefore, the present study was designed to investigate the toxicity potentials of various concentrations (0 to 1000 ppm) of WO3NPs (<100 nm particle size) in cultured primary rat hepatocytes. The results of cell viability assay showed that the higher concentrations of dispersed WO3 NPs (300, 500 and 1000 ppm) caused significant (p<0.05) decreases of cell viability. Also, dose dependent negative alterations were observed in oxidative status and antioxidant capacity levels after the application of WO3 in cultured rat primary hepatocytes. The results of genotoxicity tests revealed that these NPs did not cause significant increases of micronucleated hepatocytes (MNHEPs) but increased 8-oxo-2-deoxyguanosine (8-OH-dG) levels as compared to the control culture.

Study of structural and optical properties of zinc oxide rods grown on glasses by chemical spray pyrolysis

We have investigated morphological and optical properties of zinc oxide rods. Highly structured ZnO layers comprising with well-shaped hexagonal rods were prepared by spray pyrolysis deposition of zinc chloride aqueous solutions at ∼550°C. The rods were characterized by X-ray diffraction, scanning electron microscopy, atomic force microscopy, photoluminescence, and ultraviolet and visible absorption spectroscopy measurements. The deposition of the 0.1mol/L solution at ∼550°C resulted in crystals with a diameter of 400-1000nm and length of 500-2000nm. Sharp near-band edge emission peaks, centered at 3844 and 3680A, dominated the PL spectra of ZnO at 300K and 6.2K, respectively. In addition to this, absorption coefficient was determined by absorption measurement. X-ray diffraction, scanning electron microscopy and atomic force microscopy, results suggest that ZnO rods, prepared by spray pyrolysis, have high crystalline quality. This is desirable in nanotechnology applications.

Investigation of Structural, Morphological, Optical, and Electrical Properties of Al Doped ZnO Thin Films Via Spin Coating Technique

In this study, Al doped ZnO thin films were synthesized by sol gel spin coating technique. To investigate the effect of Al doping on ZnO properties, Al doping concentration was diversified in the range of 0–5 mol%. The effect of Al doping on structural, morphological, optical and electrical properties of ZnO thin films was evaluated by XRD, SEM, UV-VIS and four point probe measurements. All results whether pure or Al doped ZnO thin films were described in detail and they indicated that the films prepared in this study can be used in many nanotechnological applications.

Toxicity assessment of hydroxyapatite nanoparticles in rat liver cell model in vitro

Hydroxyapatite nanoparticles (HAP NPs) are widely used for preparations of biomedical and biotechnological fields such as drug delivery, gene therapy, and molecular imaging. However, the current toxicological knowledge about HAP NPs is relatively limited. The present study was designed to investigate the toxicity potentials of various concentrations (0–1000 µg cm−2) of HAP NPs in cultured primary rat hepatocytes. Cell viability was detected by 3-(4,5-dimethyl-thiazol-2-yl) 2,5-diphenyltetrazolium bromide (MTT) assay and lactate dehydrogenase (LDH) release, while total antioxidant capacity (TAC) and total oxidative stress (TOS) levels were determined to evaluate the oxidative injury. The DNA damage was also analyzed via scoring liver micronuclei rates and determining 8-oxo-2-deoxyguanosine (8-OH-dG) levels. The results of MTT and LDH assays showed that the higher concentrations of dispersed HAP NPs (300, 500, and 1000 µg cm−2) decreased cell viability. Also, HAP NPs increased TOS (500 and 1000 µg cm−2) levels and decreased TAC (300, 500, and 1000 µg cm−2) levels in cultured hepatocytes. On the basis of increasing doses, the NPs as depending on dose caused significant increases of the number of micronucleated hepatocytes and 8-OH-dG levels as compared to control culture. Furthermore, the highest concentration of HAP NPs (1000 µg cm−2) exhibited cytotoxic activity. Based on these results, HAP NPs have a dose-dependent toxic effect in rat hepatocytes. Further extensive research in this field is promising and reasonable.

Influences of Pr and Ta doping concentration on the characteristic features of FTO thin film deposited by spray pyrolysis

The Pr and Ta separately doped FTO (10 at.% F incorporated SnO2) films are fabricated via spray pyrolysis. The microstructural, topographic, optical, and electrical features of fluorine-doped TO (FTO) films are investigated as functions of Pr and Ta dopant concentrations. The x-ray diffraction (XRD) measurements reveal that all deposited films show polycrystalline tin oxide crystal property. FTO film has (200) preferential orientation, but this orientation changes to (211) direction with Pr and Ta doping ratio increasing. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) analyses show that all films have uniform and homogenous nanoparticle distributions. Furthermore, morphologies of the films depend on the ratio between Pr and Ta dopants. From ultraviolet-visible (UV-Vis) spectrophotometer measurements, it is shown that the transmittance value of FTO film decreases with Pr and Ta doping elements increasing. The band gap value of FTO film increases only at 1 at.% Ta doping level, it drops off with Pr and Ta doping ratio increasing at other doped FTO films. The electrical measurements indicate that the sheet resistance value of FTO film initially decreases with Pr and Ta doping ratio decreasing and then it increases with Pr and Ta doping ratio increasing. The highest value of figure of merit is obtained for 1 at.% Ta- and Pr-doped FTO film. These results suggest that Pr- and Ta-doped FTO films may be appealing candidates for TCO applications.

Optical Properties of ZnO Nanorods on Glass Via Spray Deposition of Solution Containing Zinc Chloride and Thiourea

In this research paper, we have investigated optical properties of two zinc oxide (ZnO) nanorods specimens grew on a glass by spray deposition of a solution, which contains only zinc chloride (ZnCl2) and ZnCl2 with small amount of thiourea (tu: CH4N2S). We sprayed a 1 mL of each solution onto a glass in every minute to obtain a 50 mL specimen. The prepared specimens were characterized by X-ray diffraction, SEM, Fourier transform infrared spectroscopy, UV-Vis absorption spectroscopy, and photoluminescence spectroscopy. We have observed from SEM measurements that small addition of thiourea into a ZnCl2 solution (ZnCl2:tu = 1:0.25) provides significantly thinner ZnO nanorods with a higher aspect ratio compared to that obtained from only ZnCl2 solution. It is noted that this addition considerably decreased the diameter of ZnO nanorods to 500 nm and increased the height to approximately 200 nm. This is desirable in nanotechnology applications. However, it is observed from PL measurements that optical properties of ZnO nanorods prepared from ZnCl2 and thiourea solution deteriorate.

Hepatic effects of yttrium oxide nanoflowers: in vitro risk evaluation

Yttrium oxide nanoflowers were prepared by a hydrothermal technique, and X-ray diffraction and scanning electron microscopy were used to determine their structures. The cytotoxic and genotoxic potentials of aqueous dispersions of the nanoflowers to cultured primary rat hepatocytes were examined at concentrations up to 500 mg L−1 for 72 h. Cell viability was determined by monitoring the reduction of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, release of lactate dehydrogenase, and uptake of neutral red. Genotoxicity was assessed by the liver micronucleus assay. Exposure to Y2O3 nanoflowers at concentrations lower than 100 mg L−1 did not lead to any cytotoxicity or genotoxicity. At higher concentrations (200, 400, and 500 mg L−1), cell viability decreased and induction of micronuclei increased (400 and 500 mg L−1).

Toxicogenomic responses of human alveolar epithelial cells to tungsten boride nanoparticles

During the recent years, microarray analysis of gene expression has become an inevitable tool for exploring toxicity of drugs and other chemicals on biological systems. Therefore, toxicogenomics is considered as a fruitful area for searching cellular pathways and mechanisms including cancer, immunological diseases, environmental responses, gene-gene interactions and chemical toxicity. In this work, we examined toxic effects of Tungsten Borides NPs on gene expression profiling of the human lung alveolar epithelial cells (HPAEpiC). In line with this purpose, a single crystal of tungsten boride (mixture of WB and W2B) nanoparticles was synthesized by means of zone melting method, and characterized via using X-ray crystallography (XRD), transmission electron microscope (TEM), scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDX) techniques. Cell viability and cytotoxicity were determined by 3-(4,5-dimethyl-thiazol-2-yl) 2,5-diphenyltetrazolium bromide (MTT), neutral red (NR) and lactate dehydrogenase (LDH) release tests. The whole genome microarray expression analysis was performed to find out the effects of WB and W2B NPs mixture on gene expression of the HPAEpiC cell culture. 123 of 40,000 gene probes were assigned to characterize expression profile for WB/W2B NPs exposure. According to results; 70 genes were up-regulated and 53 genes were down-regulated (≥2 fold change). For further investigations, these genes were functionally classified by using DAVID (The Database for Annotation, Visualization and Integrated Discovery) with gene ontology (GO) analysis. In the light of the data gained from this study, it could be concluded that the mixture of WB/W2B NPs can affect cytokine/chemokine metabolism, angiogenesis and prevent migration/invasion by activating various genes.

Choosing the Right Antioxidant Supplement for Protecting Liver from Toxicity of Engineered Nanoparticles : A Comprehensive In Vitro Screening

With the rapid development of nanotechnology, more and more nanomaterials are being fabricated and manipulated to perform the particular function, such as adhesive, biosensors, cosmetics, drug delivery system and artificial organ and tissue. On the other hand, nanotoxicity has become the topic of concern in nanotechnology because of the serious toxicity potentials of engineered nanomaterials on the living organisms. Many in vivo and in vitro studies clearly indicated that nanoparticles (NPs) are closely associated with toxicity by increasing intracellular reactive oxygen species (ROS) levels. And antioxidant supplementation is considered as useful against nanotoxicity related oxidative damages. At this point, in this investigation we assessed the protective abilities of selected 22 antioxidant or antioxidant featured agents against engineered nanoparticle exposure (ZnO NPs) model. We performed all experiments in cultured primary rat hepatocytes since the liver is a target site for NPs toxicity. Cell viability was detected by [3-(4,5-dimethyl-thiazol-2-yl) 2,5-diphenyltetrazolium bromide] (MTT) assay and lactate dehydrogenase (LDH) release, while total antioxidant capacity (TAC) and total oxidative stress (TOS) levels were determined to evaluate the oxidative alterations. Our results showed that each agent provided hepatoprotection in different degree. Propolis, boric acid and ascorbic acid were found to be the most effective ones while astaxanthine, L-glutamine and taurine were found to be less effective against nanoparticle induced oxidative injuries. The results presented here can be considered as the first information and rationale strategy on determining hepatoprotective potentials of common antioxidants against NP exposure for choosing the right antioxidant supplement for protecting liver.