Hazardous phytotoxic nature of cobalt and zinc oxide nanoparticles assessed using Allium cepa

The increasing use of nanotechnology requires the clarification of the behavior and the effects of nanoparticles (NPs) as they are released into the environment. This study was to investigate the phytotoxicity of cobalt and zinc oxide NPs using the roots of Allium cepa (onion bulbs) as an indicator organism. The effects of cobalt and zinc oxide NPs on the root elongation, root morphology, and cell morphology of a plant, as well as their adsorption potential, were determined through the hydroponic culturing of A. cepa. A. cepa roots were treated with dispersions of the cobalt and zinc oxide NPs having three different concentrations (5, 10, and 20 μg ml(-1)). With increasing concentrations of the NPs, the elongation of the roots was severely inhibited by both the cobalt and the zinc oxide NPs as compared to that in the control plant (untreated A. cepa roots). Massive adsorption of cobalt oxide NPs into the root system was responsible for the phytotoxicity. Zinc oxide NPs caused damage because of their severe accumulation in both the cellular and the chromosomal modules, thus signifying their highly hazardous phytotoxic nature.     

Acute toxicity of ferric oxide and zinc oxide nanoparticles in rats

We investigated the toxic effects of inhalation exposure to ferric oxide (Fe2O3) and zinc oxide (ZnO) nanoparticles in rats. Male Wistar rats were consecutively treated with Fe22O3 at 8.5 mg/kg body weight and ZnO nanoparticles at 2.5 mg/kg body weight, twice daily for 3 days. Content of Fe2O3 and ZnO in tissues, biochemical parameters in serum, and hispathological examinations were analyzed at 12 h and 36 h after the 3 day treatment. In the Fe2O3-treated group, iron (Fe) content in liver and lung tissues was significantly increased at 36 h. In the ZnO-treated group, zinc (Zn) content in liver tissues was significantly increased at 12 h and further increased at 36 h. The levels of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), total protein (TP), creatine kinase (CK), and lactate dehydrogenase (LDH) in both nanoparticle-exposed groups were significantly decreased compared to the unexposed controls. Histopathological examination showed that both types of nanoparticles caused severe damage in liver and lung tissues. Although this damage progressed in both liver and lung throughout the postexposure period, no significant elevation of serum enzyme activities was observed in response to either nanoparticle type.     

Synthesis of zinc and zinc oxide nanoparticles from zinc electrode using plasma in liquid

Nanoparticles are synthesized efficiently from zinc electrode by microwave plasma in liquid. The nanoparticles synthesized from alcohol resulted in pure zinc particles in the shape of spheres or hexagonal cylinders with a production rate of 3.3 g/h, and energy consumption of 267 J/mg for 1 mg. Whereas the nanoparticles synthesized in pure water are composed of Zn and ZnO. The Zn reacts with water through heat or the passage of time to become ZnO, releasing hydrogen gas. An upper disk placed 1 mm away from the electrode along with the bubbles generated simultaneously with the plasma ignition plays a key role in the synthesis of nanoparticles.     

Optical and electrical properties of aluminum-doped zinc oxide nanoparticles

Aluminum-doped zinc oxide nanopowders were prepared using a surfactant assisted complex sol–gel method, and were characterized using inductively coupled plasma, X-ray diffraction, scanning electron microscopy/energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and UV–Vis spectroscopy. Al was effectively doped into the ZnO matrix with concentrations up to 6.00 atomic ratio percents (at.%). X-ray diffraction results revealed that all of the nanoparticles had a pure hexagonal wurtzite structure free of any impurities when annealing temperature was below 1273 K. The optical band gap of the nanopowders, which was affected by the Al-doping concentration, reached a maximum of 3.43 eV when ZnO was doped with 4.00 at.% Al. The effect of post-annealing temperature and vacuum conditions on the resistivities of the Al-doped ZnO nanoparticles was also investigated. And the lowest volume resistivity (1.2 Ω cm) was achieved by annealing the Al-doped ZnO nanoparticles in a vacuum at 1173 K for 2 h.     

Formation of zinc oxide nanoparticles by mechanochemical reaction

Abstract

The synthesis of zinc oxide (ZnO) nanocrystallites by mechanochemical reaction of ZnCl₂ and Na₂CO₃ with NaCl as diluent and following thermal treatment was investigated using X-ray diffraction (XRD) and transmission electron microscopy (TEM). Calcination of the as milled powder at 600°C in air and removal of NaCl through washing formed ZnO nanocrystallites with an average crystal size of ~ 21 nm, which increased with increasing thermal treatment temperature. Milling time and NaCl/ZnCl₂ molar ratio exerted prominent effects on the crystal size of the ZnO nanoparticles. The mechanism of nanocrystallite growth is discussed.     

Chemical vapor synthesis of size-selected zinc oxide nanoparticles

ZnO can be regarded as one of the most important metal oxide semiconductors for future applications. Similar to silicon in microelectronics, it is not only important to obtain nanoscale building blocks of ZnO, but also extraordinary purity has to be ensured. A new gas-phase approach to obtain size-selected, nanocrystalline ZnO particles is presented. The tetrameric alkyl-alkoxy zinc compound [CH(3)ZnOCH(CH(3))(2)](4) is chemically transformed into ZnO, and the mechanism of gas-phase transformation is studied in detail. Furthermore, the morphological genesis of particles via gas-phase sintering is investigated, and for the first time a detailed model of the gas-phase sintering processes of ZnO is presented. Various analytical techniques (powder XRD, TEM/energy-dispersive X-ray spectroscopy, magic-angle spinning NMR spectroscopy, FTIR spectroscopy, etc.) are used to investigate the structure and purity of the samples. In particular, the defect structure of the ZnO was studied by photoluminescence spectroscopy.     

Kinetics and tissue distribution of neutron-activated zinc oxide nanoparticles and zinc nitrate in mice: effects of size and particulate nature

Although zinc oxide nanoparticles (ZnONPs) have been applied in nanotechnology, their kinetics and tissue distribution in?vivo are unknown. Here we compared the kinetics and tissue distribution of 10?nm (65)ZnONPs, 71?nm (65)ZnONPs and (65)Zn(NO(3))(2) in mice after intravenous injection. The areas under the curves and the half-lives in the second compartment of (65)Zn(NO(3))(2) were greater than those of (65)ZnONPs; the kinetic parameters were similar for both (65)ZnONPs. However, the tissue distributions for the three forms were different. ZnONPs preferentially accumulated in the liver and spleen at 24?h. At day 28, (65)Zn concentration was highest in bone and the proportion of recovered (65)Zn radioactivity was highest in the carcass; these had the same ranking, 10?nm (65)ZnONPs?>?71?nm (65)ZnONPs> (65)Zn(NO(3))(2). Although more than 80% of the 10?nm (65)ZnONPs had been excreted by day 28, greater amounts of the 10?nm (65)ZnONPs than the 71?nm (65)ZnONPs or (65)Zn(NO(3))(2) had accumulated in other organs (brain, lung, heart and kidneys). Zn ions seem to have a longer half-life in the plasma, but ZnONPs show greater tissue accumulation. Although the size of the ZnONPs had no obvious effect on the kinetics, nevertheless the smaller ZnONPs tended to accumulate preferentially in some organs.     

Synthesis and anti-ultraviolet properties of monodisperse BSA-conjugated zinc oxide nanoparticles

A three-step process was designed to fabricate bovine serum albumin (BSA)-conjugated zinc oxide nanoparticles (BZnOs) by using BSA as the structure directing agent. The morphology and crystal phase of BZnOs were characterized by transmission electron microscopy (TEM) and powder X-ray diffraction (XRD). The composition and BSA content of BZnOs were measured by Fourier transform infrared spectrograph (FTIR) and thermogravimetry (TG) analysis. The ultraviolet-visible absorption property and ultraviolet blocking effects of BZnOs were also studied. The results indicated that the monodisperse BZnOs with 20.5 ± 3.5 nm in diameter had better anti-ultraviolet activities and exhibited the potential as the sunscreen.     

Cytotoxicity of zinc oxide nanoparticles: importance of microenvironment

While ZnO particles are widely used in many fields, including personal care products, the high toxicity of ZnO nanoparticles has been reported and aroused great health concerns. In this study, the cytotoxicity of ZnO nanoparticles was evaluated and, in particular, the role of microenvironment in their toxicity was investigated. Our results show that ZnO nanoparticles are highly toxic to NIH/3T3 cells, inducing viability loss, membrane leakage and morphology changes. The microenviroment, here the CO2 atmosphere under cell culture condition, promoted the solubilization of ZnO nanoparticles. Then the released Zn from ZnO nanoparticles induces the cytotoxicity. The importance of microenvironment on the ZnO nanotoxicity is presented and the implications to future nanotoxicology studies are discussed.     

Controllable preparation and sterilization activity of zinc aluminium oxide nanoparticles

The zinc aluminium oxide (ZAO) NPs with homogeneous dispersion and crystal stability were prepared through synergistic reaction with ultrasonic-microwave and different dispersants. The products were characterized by X-ray diffraction analysis, transmission electron microscopy and UV–vis absorption spectra. The ZAO NPs of 45, 30, 25 and 20 nm in diameter could be controllably obtained under the same reaction conditions. These ZAO NPs were high crystalline and with wurtzite crystal structure. Specially, the sterilization activity of ZAO NPs was investigated firstly. Our bacteriological study showed the enhanced sterilization activity of ZAO NPs compared with ZnO NPs. This demonstrated that the bactericidal efficacy of ZAO NPs increases with decreasing particle size.     

PEGylated zinc oxide nanoparticles induce apoptosis in pancreatic cancer cells through reactive oxygen species

In this study, the authors have successfully prepared the polyethylene glycol (PEG)‐coated zinc oxide nanoparticles (ZNPs) and studied its effect in pancreatic cancer cells. The authors have observed a nanosized particle with spherical shape. In this study, the authors have demonstrated the cytotoxic effect of ZNP and PZNP in PANC1 cells. To be specific, PZNP was more cytotoxic compared to that of ZNP in PANC1 cancer cells. The authors have further showed that apoptosis is the main mode of cytotoxic activity. It is worth noting that PEGylation of ZNP did not decrease the cell killing activity of zinc particles, whereas it further increases its anticancer effect in the pancreatic cancer cells. The authors have observed a significant upregulation of proapoptotic BAX while expression of antiapoptotic Bcl‐2 was significantly downregulated indicating the potent anticancer effect of zinc nanoparticles. Overall, PEGylation of ZNP could be an effective strategy to improve the stability, while at the same time, its anticancer activity could be enhanced for better therapeutic response.Inspec keywords: biomedical materials, drug delivery systems, tumours, toxicology, nanoparticles, cellular biophysics, drugs, nanomedicine, cancer, nanofabrication, zinc compounds, II‐VI semiconductorsOther keywords: pancreatic cancer cells, reactive oxygen species, polyethylene glycol‐coated zinc oxide nanoparticles, cytotoxic effect, cytotoxic activity, PEGylation, anticancer effect, PEGylated zinc oxide nanoparticle induce apoptosis, proapoptotic BAX upregulation, ZnO     

一种制备ZnO纳米颗粒的新方法

提出了一种制备ZnO纳米颗粒的新方法。在金属钠的液氨溶液中还原硝酸锌,所形成的金属Zn自然氧化而制得ZnO颗粒。为了研究表面修饰对产物形貌、粒径和性能的影响,制备了十二烷基磺酸钠（SDS）修饰的ZnO纳米颗粒。采用X射线粉末衍射仪（XRD）、透射电子显微镜（TEM）、傅立叶变换红外光谱仪（FT-IR）、热重及差热分析仪（TG-DTA）等手段对产物进行了表征。结果表明采用该方法可制得具有六方纤锌矿结构的ZnO颗粒,未修饰ZnO颗粒团聚较为严重;修饰的ZnO纳米颗粒呈棒状,分散较好。红外和热分析表明SDS修饰在了ZnO纳米颗粒表面。测试了所制备ZnO颗粒的紫外可见吸收（UV-Vis）和光致发光（PL）谱,均出现了ZnO的特征谱带。提出的方法也适用于制备其它金属或氧化物纳米材料。     

Effect of film thickness in hybrid polymer/polymer solar cells with zinc oxide nanoparticles

We briefly report the effect of film thickness on the performance of hybrid polymer/polymer solar cells that were made using poly(3-hexylthiophene), poly(9,9-dioctylfluorene-co-benzothiadiazole) (F8BT), and zinc oxide (ZnO) nanoparticles. The ZnO nanoparticles were introduced to improve the electron transport property of P3HT/F8BT blend films. Results showed that the open circuit voltage (V(OC)) was remarkably decreased by adding only approximately 0.5 wt% ZnO nanoparticles though the optical absorption spectra were not much changed due to the small amount of ZnO nanoparticles in the ternary blend films (approximately 1.9%). In contrast, the fill factor (FF) of devices was improved for the ternary blend devices with the ZnO nanoparticles due to the improved electron transport as evidenced by the reduced series resistance. The short circuit current density of devices was not much changed because of the enhanced charge transport. However, the addition of ZnO nanoparticles decreased the power conversion efficiency of devices owing to the larger influence of V(OC) compared to the FF improvement.     

Functional finishing in cotton fabrics using zinc oxide nanoparticles

Nanotechnology, according to the National Nanotechnology Initiative (NNI), is defined as utilization of structure with at least one dimension of nanometer size for the construction of materials, devices or systems with novel or significantly improved properties due to their nano-size. The nanostructures are capable of enhancing the physical properties of conventional textiles, in areas such as anti-microbial properties, water repellence, soil-resistance, anti-static, anti-infrared and flame-retardant properties, dyeability, colour fastness and strength of textile materials. In the present work, zinc oxide nanoparticles were prepared by wet chemical method using zinc nitrate and sodium hydroxide as precursors and soluble starch as stabilizing agent. These nanoparticles, which have an average size of 40 nm, were coated on the bleached cotton fabrics (plain weave, 30 s count) using acrylic binder and functional properties of coated fabrics were studied. On an average of 75%, UV blocking was recorded for the cotton fabrics treated with 2% ZnO nanoparticles. Air permeability of the nano-ZnO coated fabrics was significantly higher than the control, hence the increased breathability. In case of nano-ZnO coated fabric, due to its nano-size and uniform distribution, friction was significantly lower than the bulk-ZnO coated fabric as studied by Instron® Automated Materials Testing System. Further studies are under way to evaluate wash fastness, antimicrobial properties, abrasion properties and fabric handle properties.     

Selective toxicity of zinc oxide nanoparticles to prokaryotic and eukaryotic systems

We report on the toxicity of ZnO nanoparticles (NPs) to gram-negative and gram-positive bacterial systems, Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), and primary human immune cells. ZnO NP (~13 nm) showed complete inhibition of E. coli growth at concentrations 3.4 mM, whereas growth of S. aureus was completely inhibited for 1 mM. Parallel experiments using flow cytometry based assays clearly demonstrated that growth inhibitory properties of ZnO NP were accompanied by a corresponding loss of cell viability. Identical ZnO NP had minimal effects on primary human T cell viability at concentrations toxic to both gram-negative and gram-positive bacteria. Collectively, these experiments demonstrate selectivity in the toxic nature of ZnO NP to different bacterial systems and human T lymphocytes. Developing selective toxicity to biological systems and controlling it by NP design could lead to biomedical and antibacterial applications.     

Electrical and gas sensing properties of self-aligned copper-doped zinc oxide nanoparticles

Electrical and gas sensing properties of nanocrystalline ZnO:Cu, having Cu X wt% (X = 0.0, 0.5, 1.0, and 1.5) in ZnO, in the form of pellet were investigated. Copper chloride and zinc acetate were used as precursors along with oxalic acid as a precipitating reagent in methanol. Material characterization was done by X-ray diffraction (XRD), scanning electron microscopy (SEM), field emission scanning electron microscopy (FE-SEM) and inductive coupled plasma with optical emission spectrometry (ICP-OES). FE-SEM showed the self-aligned Cu-doped ZnO nano-clusters with particles in the range of 40-45 nm. The doping of 0.5% of copper changes the electrical conductivity by an order of magnitude whereas the temperature coefficient of resistance (TCR) reduces with increase in copper wt% in ZnO. The material has shown an excellent sensitivity for the H₂, LPG and CO gases with limited temperature selectivity through the optimized operating temperature of 130, 190 and 220 °C for H₂, LPG and CO gases, respectively at 625 ppm gas concentration. The %SF was observed to be 1460 for H₂ at 1% Cu doping whereas the 0.5% Cu doping offered %SF of 950 and 520 for CO and LPG, respectively. The response and recovery time was found to be 6 to 8 s and 16 s, respectively.     

Protective role of biosynthesised zinc oxide nanoparticles on pancreatic beta cells: an in vitro and in vivo approach

Sulphonylureas are extensively used in the treatment of type II diabetes; however, these drugs have complications of hypoglycaemia and weight gain. The current study aims at developing a potent antidiabetic drug that has lesser side effects and better management of its associated conditions. Zinc oxide nanoparticles (ZnO NPs) were synthesised using Syzygium cumini seed extract with an average size of 18.92 nm. In vitro studies on rat insulinoma (RIN‐5F) cells revealed that cells treated with synthesised ZnO NPs showed a dose‐dependent increase in insulin secretion. Streptozotocin‐fructose‐induced type II diabetic rats treated with ZnO NPS exhibited a significant reduction (p  < 0.01) in the blood glucose levels, total cholesterol, triglycerides, and low‐density lipoprotein levels and increase (p  < 0.01) in serum insulin and liver antioxidant enzyme levels proclaiming its role as a hypoglycaemic and hypolipidaemic drug. Treatment of ZnO NPs in diabetic rats exhibited an increased number of beta cells which was responsible for its increased insulin levels and reduced glucose levels. From the overall observations, biosynthesised ZnO NPs exhibited an efficacious hypoglycaemic effect in diabetic rats, so it can be suggested as a potent antidiabetic drug.Inspec keywords: biochemistry, II‐VI semiconductors, drug delivery systems, drugs, patient treatment, blood, enzymes, zinc compounds, molecular biophysics, sugar, cellular biophysics, nanofabrication, liver, nanoparticles, diseases, biomedical materials, nanomedicineOther keywords: protective role, biosynthesised zinc oxide nanoparticles, pancreatic beta cells, vivo approach, type II diabetes, drugs, hypoglycaemia, weight gain, potent antidiabetic drug, lesser side effects, associated conditions, Syzygium cumini seed, rat insulinoma, synthesised ZnO NPs, dose‐dependent increase, insulin secretion, streptozotocin‐fructose‐induced type II diabetic rats, blood glucose levels, low‐density lipoprotein levels, serum insulin, liver antioxidant enzyme levels, hypoglycaemic drug, hypolipidaemic drug, increased insulin levels, reduced glucose levels, biosynthesised ZnO NPs, efficacious hypoglycaemic effect, size 18.92 nm, temperature 5.0 F, ZnO     

Annealing effects on 5 nm iron oxide nanoparticles

Morphological, structural and magnetic properties of 4.8 nm iron oxide nanoparticles have been investigated after annealing under inert atmosphere at different temperatures. The as-prepared iron oxide nanoparticles have been synthesized by chemical route from high temperature reaction of Fe(acac)3 solution in presence of oleic acid and oleylamine surfactant. Annealing the particles at low temperatures (Tann = 573 K) produces an increment of the mean size from 4.8 nm to 6.0 nm, preserving the same morphology. The coercive field of the annealed sample has a small increasing with respect to the as-prepared sample in agreement with the mean particle volume change. Annealing at higher temperature (Tann = 823 K) leads to a bimodal size distribution of the iron oxide nanoparticles with 6.0 nm and 17 nm mean sizes respectively, where the bigger particles dominate the observed magnetic properties.     

Formation of zinc oxide nanoparticles during electric discharge in water

A method for obtaining nanodimensional structures of zinc oxide (ZnO) by means of electric discharge in water is described. Data on the phase composition and luminescent properties of the synthesized ZnO powder deposited from a colloidal solution onto single crystal silicon surface are presented. It is shown that the partial concentrations of zinc in the oxide and metallic phases in the colloidal solution depend on the supply of oxygen to the zone of the chemical reaction. Optimum conditions for the discharge synthesis of nanodimensional powder with an almost 100% ZnO content have been found.     

Biosynthesis of zinc oxide nanoparticles using anjbar (root of Persicaria bistorta) extract and their cytotoxic effects on human breast cancer cell line (MCF‐7)

Biosynthesis of nanoparticles (NPs) using biomass is now one of the best methods for synthesising NPs due to their nontoxic and biocompatibility. Plants are the best choice among all biomass to synthesise large‐scale NPs. The objectives of this study were to synthesise zinc oxide nanoparticles (ZnO‐NPs) using Anjbar (root of Persicaria bistorta) [An/ZnO‐NPs] and investigate the cytotoxic and anti‐oxidant effects. For this purpose, the An/ZnO‐NPs were synthesised by using Bistort extract and characterised using UV–Visible spectroscopy, transmission electron microscope, field emission scanning electron microscope, x‐ray diffraction and Fourier‐transform infrared spectroscopy. The cytotoxic effects of the An/ZnO‐NPs on MCF‐7 cells were followed by 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide assays at 24, 48, and 72 h. Nuclear morphology changed and apoptosis in cells was investigated using acridine orange/propodium iodide (AO/PI) staining and flow cytometry analysis. The pure biosynthesised ZnO‐NPs were spherical in shape and particles sizes ranged from 1 to 50 nm. Treated MCF‐7 cells with different concentrations of ZnO‐NPs inhibited cell viability in a time‐ and dose‐dependent manner with IC50 about 32 μg/ml after 48 h of incubation. In flow cytometry analysis the sub‐G1 population, which indicated apoptotic cells, increased from 12.6% at 0 μg/ml (control) to 92.8% at 60 μg/ml, 48 h after exposure. AO/PI staining showed that the treated cells displayed morphologic evidence of apoptosis, compared to untreated groups. Inspec keywords: cancer, cellular biophysics, toxicology, particle size, nanofabrication, X‐ray diffraction, nanomedicine, nanoparticles, ultraviolet spectra, scanning electron microscopy, visible spectra, transmission electron microscopy, patient treatment, field emission electron microscopy, Fourier transform infrared spectra, drug delivery systemsOther keywords: anjbar, cytotoxic effects, human breast cancer cell line, biomass, transmission electron microscope, field emission scanning electron microscope, Fourier‐transform infrared spectroscopy, flow cytometry analysis, ZnO‐NPs inhibited cell viability, antioxidant effects, MCF‐7 cells, biosynthesised ZnO‐NP, biosynthesised ZnO‐NP, acridine orange‐propodium iodide staining, An‐ZnO‐NP, Persicaria bistorta, zinc oxide nanoparticle biosynthesis, 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide