Nanoscale Zinc Oxide Particles Research Articles

Synthesis of Zinc Oxide Nanoflakes by Non-Thermal Plasma Technique and Evaluation of Anticancer Activity in Vitro

This paper describes the synthesis of ZnO nanoparticles using air microplasma jets as the main reaction medium. Various techniques, including X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and UV—Vis spectroscopy, were employed to confirm the characterization of the artificially synthesized ZnO nanoparticles. The absence of additional peaks associated with secondary phases of ZnO, as revealed by the XRD analysis, indicates the exceptional purity of these nanoparticles. Through the use of SEM, we examined the surface morphology and observed a substantial rate of agglomeration. The energy band gaps of ZnO nanoparticles were determined to be 3.3 electron volts (eV). The cytotoxic effects of zinc oxide nanoparticles were assessed using the methyl thiazolyl tetrazolium (MTT) assay on breast cancer cells exposed to various doses of the nanoparticles. The Acridine-Orange/Ethidium-bromide (AO/EB) dual stain was employed to assess apoptotic cells. The data indicate that ZnO NPs can induce apoptosis, suggesting their potential as an anticancer treatment in breast cancer cell lines. The presented findings indicate that nanoscale zinc oxide particles (ZnO NPs) possess significant potential for future utilization in many biological applications. An example of such an application could be the prospective substitution for chemotherapy in the management of various forms of cancer diseases.

Seed Priming and Coating by Nano-Scale Zinc Oxide Particles Improved Vegetative Growth, Yield and Quality of Fodder Maize (Zea mays)

Nano-fertilizers of essential plant nutrients, including micronutrients, have the potential to improve nutrient use efficiency and productivity of field crops in deficient soils. The present study reports the comparative influence of zinc oxide nanoparticles (ZnONPs) and bulk Zn salt (ZnSO4) on the growth, yield, and quality of fodder maize (Zea mays) (var. J-1006) cultivated under field conditions in the year 2019. Three levels (0, 20, and 40 mg L−1) of Zn fertilizers were used for seed priming and coating in triplicate following the randomized complete block design model. An increase in vegetative and yield parameters (number of plants, plant height, stover yield, plant biomass), acid detergent fiber (ADF%), and hemicellulose contents and shoot zinc (Zn) content on treatment of seeds with ZnONPs (20 mg L−1) concentration as compared to bulk ZnSO4 and control treatments was observed. The application of ZnONPs (40 mg L−1) significantly enhanced the total chlorophyll content, available soil nitrogen and phosphorus, neutral detergent fiber (NDF%), and cellulose contents and improved the total soil microbial counts and soil enzyme activities (dehydrogenase, acid and alkaline phosphatase enzyme activities), whereas a significant increase in available soil potassium and zinc contents was recorded under ZnONPs (20 mg L−1) treatments. These findings suggest an encouraging effect on the growth and yield attributing characteristics of fodder maize after ZnONPs seed coating at low concentration. Furthermore, ZnONPs seed coating can also be considered an effective tool for the delivery of Zn micronutrient to fodder maize crop.

Nanoscale Zinc Oxide Particles for Improving the Physiological and Sanitary Quality of a Mexican Landrace of Red Maize.

In this research, quasi-spherical-shaped zinc oxide nanoparticles (ZnO NPs) were synthesized by a simple cost-competitive aqueous precipitation method. The engineered NPs were characterized using several validation methodologies: UV–Vis spectroscopy, diffuse reflection UV–Vis, spectrofluorometry, transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), and Fourier transform infrared (FTIR) spectroscopy with attenuated total reflection (ATR). A procedure was established to coat a landrace of red maize using gelatinized maize starch. Each maize seed was treated with 0.16 mg ZnO NPs (~7.7 × 109 particles). The standard germination (SG) and accelerated aging (AA) tests indicated that ZnO NP-treated maize seeds presented better physiological quality (higher percentage of normal seedlings) and sanitary quality (lower percentage of seeds contaminated by microorganisms) as compared to controls. The application of ZnO NPs also improved seedling vigor, correlated to shoot length, shoot diameter, root length, and number of secondary roots. Furthermore, shoots and roots of the ZnO NP-treated maize seeds showed a marked increment in the main active FTIR band areas, most notably for the vibrations associated with peptide-protein, lipid, lignin, polysaccharide, hemicellulose, cellulose, and carbohydrate. From these results, it is concluded that ZnO NPs have potential for applications in peasant agriculture to improve the quality of small-scale farmers’ seeds and, as a result, preserve germplasm resources.

Electrodeposited nanoscale zinc oxide particles: facilitating the electron transfer of immobilised protein and biosensing

The electron transfer of redox-active sites of immobilised haemoglobin (Hb) has been studied by voltammetric experiments. The electrode surface was modified by nanoparticles (NPs) to make a suitable substrate for electric wiring of protein molecules and efficient electron transferring. Hence, the Hb/zinc oxide NPs/platinum electrode was prepared by chronoamperometric deposition of the NPs and immobilisation of protein molecules. The electrochemical behaviour of the prepared biosensor was quasi-reversible and showed a pair of redox peaks with a formal potential (E 0′) of 214 mV. Additionally, the electron transfer rate constant (ks ) of immobilised Hb was about 0.621 s−1. Biocatalytic reduction of hydrogen peroxide was also examined on the prepared biosensor. Result indicated to good sensitivity, wide linear range and low detection limit of 6 μM.

Improvement of Thermoelectric Properties of Bi0.4Sb1.6Te3 with Addition of Nanoscale Zinc Oxide Particles

Bulk Bi0.4Sb1.6Te3 materials with ZnO nanoinclusions have been fabricated by mechanical alloying and plasma-activated sintering. The effects of ZnO addition on the microstructure and thermoelectric performance of the Bi0.4Sb1.6Te3 materials have been studied in detail. Scanning electron microscopy (SEM) observation confirms that the ZnO particles distribute in the Bi0.4Sb1.6Te3 matrix homogeneously until the content is over 0.5 wt.%. The resistivity and Seebeck coefficient of the samples increase slightly with the ZnO content, while the thermal conductivity is reduced effectively by addition of ZnO nanoparticles due to extra phonon scattering at ZnO nanoinclusions, and a maximum ZT of 1.21 is achieved in the sample with 0.3 wt.% ZnO at 373 K.

Nano Technology in the production of protective clothing for users exposed to the danger of Ultra violet rays

The study was interested in nanotechnology and zinc oxide nanoparticles because of their properties that allow us to use them in the production of protective clothing for some groups exposed to the risk of ultraviolet rays, as the researcher treated the cloth under study with three concentrations of nanoscale zinc oxide particles (0.5-0.75- 1 g / ml), as well as the study concerned with improving the knitting techniques in line with the efficiency of the processing performance, as the knitting was carried out with the simple and English connection with three knitting stitch densities (3-5-7 stitches / cm) and then conducting laboratory tests to know the change in the properties of the fabric resulting from the treatment And to determine the best techniques for knitting so that the protective garment can perform its purpose with the highest efficiency and quality, and it is evident from the laboratory analysis that treating the fabric under study with nanoscale zinc oxide particles improves some properties of the cloth such as (softness - durability - high rate of protection from UV rays - resistance to bacteria), where the improvement of these properties increases further. By increasing the concentration of nanoscale zinc oxide particles. It has also been proven that treating the cloth under study with nanometric zinc oxide particles reduces some of the fabric's properties such as (air permeability - impregnation) due to the result of the treatment, where the spaces between the fabric fibers are filled with nanometric zinc oxide particles, which reduces its permeability to air and water, but by an acceptable rate. The research also found that treating the studied fabric with nanoscale zinc oxide particles gives it the property of resistance to bacteria, which increases with increasing the concentration of nanometer zinc oxide particles, and that the difference in the density of the sewing stitches under study affects the value of the UPF protection factor from ultraviolet rays, and this is evident in the simple link where The stitch density (7 stitches / cm) achieves the highest protection. Also, the difference in the type of the sewing joint under study gave a better protection coefficient (UPF) with that of the English L-S joint.

EFFECT OF NANOSCALE ZINC OXIDE PARTICLES ON THE GERMINATION, GROWTH AND YIELD OF PEANUT

An investigation was initiated to examine the effects of nanoscale zinc oxide particles on plant growth and development. In view of the widespread cultivation of peanut in India and in other parts of the globe and in view of the potential influence of zinc on its growth, this plant was chosen as the model system. Peanut seeds were separately treated with different concentrations of nanoscale zinc oxide (ZnO) and chelated bulk zinc sulfate (ZnSO4) suspensions (a common zinc supplement), respectively and the effect this treatment had on seed germination, seedling vigor, plant growth, flowering, chlorophyll content, pod yield and root growth were studied. Treatment of nanoscale ZnO (25 nm mean particle size) at 1000 ppm concentration promoted both seed germination and seedling vigor and in turn showed early establishment in soil manifested by early flowering and higher leaf chlorophyll content. These particles proved effective in increasing stem and root growth. Pod yield per plant was 34% higher compared to chelated bulk ZnSO4. Consequently, a field experiment was conducted during Rabi seasons of 2008–2009 and 2009–2010 with the foliar application of nanoscale ZnO particles at 15 times lower dose compared to the chelated ZnSO4 recommended and we recorded 29.5% and 26.3% higher pod yield, respectively, compared to chelated ZnSO4. The inhibitory effect with higher nanoparticle concentration (2000 ppm) reveals the need for judicious usage of these particles in such applications. This is the first report on the effect of nanoscale particles on peanut growth and yield.

Microwave-assisted hydrothermal synthesis of zinc oxide particles starting from chloride precursor

Zinc oxide (ZnO) was synthesized using a microwave assisted hydrothermal (MAH) process based on chloride/urea/water solution and under 800 W irradiation for 5 min. In the bath, Zn 2+ ions reacted with the complex carbonate and hydroxide ions to form zinc carbonate hydroxide hydrate (Zn 4CO 3(OH) 6·H 2O), and the conversion from Zn 4CO 3(OH) 6·H 2O to ZnO was synchronously achieved by a MAH process. The as-prepared ZnO has a sponge-like morphology. However, the initial sponge-like morphology of ZnO could change to a net-like structure after thermal treatment, and compact nano-scale ZnO particles were finally obtained when the period of thermal treatment increased to 30 min. Pure ZnO nanoparticles was obtained from calcination of loose sponge-like ZnO particles at 500 °C. The analysis of optical properties of these ZnO nanoparticles showed that the intensity of 393 nm emission increased with the calcination temperature because the defects were reduced and the crystallinity was improved.

Synthesis, Characterization, Defect Chemistry, and FET Properties of Microwave-Derived Nanoscaled Zinc Oxide

The formation of nanoscale zinc oxide particles with an almost-monomodal size distribution synthesized by microwave heating of solutions of mononuclear zinc oximato or zinc acetylacetonato complexes in various alkoxyethanols is investigated. Transparent stable suspensions that contain these particles can be obtained from the zinc oximato precursor. Based on electron paramagnetic resonance (EPR) studies, a core/shell model with a finite surface shell thickness of 1.000 ± 0.025 nm is proposed for the ZnO nanoparticles. Field-effect transistor (FET) devices with these ZnO particles as the active semiconducting layer exhibited a charge carrier mobility of 0.045 cm2/(V s) and Ion/off current ratios of ∼460.000, with a threshold voltage of 8.78 V.

Can in vitro assays substitute for in vivo studies in assessing the pulmonary hazards of fine and nanoscale materials?

Risk evaluations for nanomaterials require the generation of hazard data as well as exposure assessments. Most of the validated nanotoxicity studies have been conducted using in vivo experimental designs. It would be highly desirable to develop in vitro pulmonary hazard tests to assess the toxicity of fine and nanoscale particle-types. However, in vitro evaluations for pulmonary hazards are known to have limited predictive value for identifying in vivo lung toxicity effects. Accordingly, this study investigated the capacity of in vitro screening studies to predict in vivo pulmonary toxicity of several fine or nanoparticle-types following exposures in rats. Initially, complete physicochemical characterization of particulates was conducted, both in the dry and wet states. Second, rats were exposed by intratracheal instillation to 1 or 5 mg/kg of the following particle-types: carbonyl iron, crystalline silica, amorphous silica, nanoscale zinc oxide, or fine zinc oxide. Inflammation and cytotoxicity endpoints were measured at 24 h, 1 week, 1 month and 3 months post-instillation exposure. In addition, histopathological analyses of lung tissues were conducted at 3 months post-exposure. Pulmonary cell in vitro studies consisted of three different culture conditions at 4 different time periods. These included (1) rat L2 lung epithelial cells, (2) primary rat alveolar macrophages, and (3) alveolar macrophage—L2 lung epithelial cell co-cultures which were incubated with the same particles as tested in the in vivo study for 1, 4, 24, or 48 h. Cell culture fluids were evaluated for cytotoxicity endpoints and inflammatory cytokines at the different time periods in an attempt to match the biomarkers assessed in the in vivo study. Results of in vivo pulmonary toxicity studies demonstrated that instilled carbonyl iron particles produced little toxicity. Crystalline silica and amorphous silica particle exposures produced substantial inflammatory and cytotoxic effects initially, but only the crystalline silica variety produced sustained and progressive inflammatory and cytotoxic responses, leading to the development of pulmonary fibrosis. Exposures to nanoscale or fine-sized zinc oxide particles produced potent but typical “metal fume fever”-like reversible inflammation/cytotoxic effects which were resolved by 1-month postinstillation exposure. In contrast to the in vivo results, using cytotoxicity and inflammation endpoints, in vitro effects to the various particle-types were difficult to gauge, owing to the number of variables that were studied (i.e., cell-types, time-course, dose response (including particle overload doses)), and various endpoints (e.g., cytotoxicity = LDH, MTT; inflammation/cytokines = MIP-2). For instance, none of the in vitro endpoints could mimic a transient inflammatory/cytotoxic response—as was measured following exposures to amorphous silica, or fine or nanoscale zinc oxide particles. We conclude that current in vitro cell culture systems do not accurately forecast the pulmonary hazard responses of instilled particle-types. It seems clear that in vitro cellular systems will need to be further developed, standardized, and validated (relative to in vivo effects) in order to provide useful screening data on the relative toxicity of inhaled particles.

Synthesis and characterization of nanoscale zinc oxide particles: I. laser vaporization / condensation technique

A method which combines laser vaporization of metal targets with controlled condensation in a diffusion cloud chamber is used to synthesize nanoscale metal oxide and metal carbide particles (10 – 20 nm). In this work we present the results for the synthesis and characterization of ZnO as an example of metal oxide nanoparticles. In part II (this issue), we present the results for silicon carbide nanoparticles synthesized using the same method described here.