Application Of Cu Nanoparticles Research Articles

Changes of the antioxidant system in pear (Pyrus communis L.) fruits by foliar application of copper, selenium, iron, and zinc nanoparticles

Innovations in agricultural nanotechnology are a viable option for improving the antioxidant system in the pear crop helping to mitigate the different types of abiotic and biotic stresses whose effects have increased due to the advance of climate change. Therefore, foliar applications were made with nanoparticles (NPs) of copper (Cu), iron (Fe), and zinc (Zn) at 250 ppm, as well as applications with selenium (Se) at 50 ppm, and control with water in a commercial pear orchard (Bartlett variety), to evaluate its effect on the behavior of the enzymatic antioxidant system, the concentration of bioactive compounds, and the evaluation of damage by lipid peroxidation, hydrogen peroxide concentration, and activity of polyphenol oxidases (PPO) in the fruits. The results indicate that the Cu and Se NPs stimulated in the fruits a greater synthesis of total phenols, flavonoids, and ascorbic acid, achieving higher concentrations than the control fruits, and also exhibited greater antioxidant activity in vitro. An opposite effect was observed in the fruits of the treatment with Zn NPs, since the concentration of phenols and flavonoids was reduced by 33.14 and 34.24 %, respectively, as well as a decrease in antioxidant activity. On the other hand, the Cu and Fe NPs improved the activity of the enzymes superoxide dismutase, catalase, ascorbate peroxidase, and guaiacol peroxidase, additionally, the integrity of the membranes was maintained, thus avoiding enzymatic browning due to the activity of the PPOs in the fruits. The highest concentration of malondialdehyde and PPOs activity was observed in the fruits of the treatment with Se and Zn NPs. The results indicate that the application of Cu NPs at 250 ppm can improve the enzymatic and non-enzymatic antioxidant system in Bartlett cultivar pear fruits.

Biosynthesis of Copper Nanoparticles From Seaweed Ulva lactuca and Their In Vitro Antioxidative Potential.

Marine macroalgae is consumed by individuals in several regions, including Scandinavia, Great Britain, Ireland, China, and Japan; in Japan, it is commonly referred to as aosa. Copper nanoparticles are primarily composed of copper and exhibit a size distribution ranging from 1 to 100 nm. Copper nanoparticles can be synthesized using chemical or natural means, similar to other nanoparticle variants. The nanoparticles in question have garnered significant attention owing to their historical utilization as coloring agents, as well as their contemporary applicability in medicine and antibacterial treatments. The objective of this study was to investigate the biosynthesis of copper nanoparticles derived from Ulva lactuca seaweed and explore their in vitro antioxidative potential. Seaweed samples (10 g) were mixed with 50 ml of distilled water and placed in a shaker for two days. Copper sulfate (10 mM) was mixed with 100 ml of distilled water to obtain a copper (Cu) solution. Cu nanoparticles were then synthesized by adding the aqueous extract to 100 ml of the Cu solution and mixing it in an orbital shaker at 180 rpm for 24 hours. They were observed both visually and via ultraviolet(UV) spectrophotometry to confirm their nanoparticle synthesis. The initial reading was performed using a UV-visible spectrometer at 300-800 nm. The sample was centrifuged at approximately 8000 rpm for 15 minutes, the pellet was removed, and the pellet was dried in a hot-air oven. The synthesized Cu nanoparticles were then investigated using in vitro antioxidant assays. The seaweed-derived copper nanoparticles exhibited a 1.2 peak absorbance at 580 nm. Various concentrations of copper nanoparticles (25, 50, 75, and 100 µg/ml) were tested for free radical scavenging. As the copper nanoparticle concentration increased, the scavenging ability on 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radicals assay showed that the free radical scavenging activity increased in a dose-dependent manner. Similar to the DPPH assay, the total antioxidant and hydrogen peroxide (H2O2)assays showed increased free radical scavenging with increasing concentration. The application of Cu nanoparticles in the synthesis process has the potential to enhance the antioxidant activity of Ulva lactuca as evidenced by the observed increase in antioxidant capacity and defense against reactive oxygen species.

Application of Cu Nanoparticles in Chitosan-PVA Hydrogels in a Native Tomato Genotype: Evaluation of the Postharvest Behavior of the Physicochemical and Bioactive Components of the Fruits

Application of Cu Nanoparticles in Chitosan-PVA Hydrogels in a Native Tomato Genotype: Evaluation of the Postharvest Behavior of the Physicochemical and Bioactive Components of the Fruits

Responses of Tomato Plants under Saline Stress to Foliar Application of Copper Nanoparticles.

The tomato crop has great economic and nutritional importance; however, it can be adversely affected by salt stress. The objective of this research is to quantify the agronomic and biochemical responses of tomato plants developed under salt stress with the foliar application of copper nanoparticles. Four treatments were evaluated: foliar application of copper nanoparticles (250 mg L−1) with or without salt stress (50 mM NaCl), salt stress, and an absolute control. Saline stress caused severe damage to the development of tomato plants; however, the damage was mitigated by the foliar application of copper nanoparticles, which increased performance and improved the Na+/K+ ratio. The content of Cu increased in the tissues of tomato plants under salinity with the application of Cu nanoparticles, which increased the phenols (16%) in the leaves and the content of vitamin C (80%), glutathione (GSH) (81%), and phenols (7.8%) in the fruit compared with the control. Similarly, the enzyme activity of phenylalanine ammonia lyase (PAL), ascorbate peroxidase (APX), glutathione peroxidase (GPX), superoxide dismutase (SOD), and catalase (CAT) increased in leaf tissue by 104%, 140%, 26%, 8%, and 93%, respectively. Foliar spraying of copper nanoparticles on tomatoes under salinity appears to induce stress tolerance to salinity by stimulating the plant’s antioxidant mechanisms.

Cu-based N-doped/undoped graphene nanocomposites as electrocatalysts for the oxygen reduction

The development of efficient electrocatalysts for the energy-related reactions, based on earth-abundant elements, is extremely important for a sustainable energetic future. Herein, we report the application of Cu nanoparticles supported on undoped and N-doped graphene—Cu/GOE and Cu/GOE-u composites, respectively—as electrocatalysts for the oxygen reduction reaction (ORR). All the materials showed ORR electrocatalytic activities in alkaline medium. The Cu/GOE-u composite exhibited the most promising performance, with an onset potential of 0.84 V and a current density of jL = − 4.4 mA cm−2 (vs. 0.84 V and − 2.8 mA cm−2 for Cu/GOE), which revealed the great influence of the created Cu–Nx/C active sites on the ORR electrocatalytic activity. The pure GOE-u support showed worse performance than the GOE, demonstrating that the N-doping advantage is not linear and also depends on the type and amount of accessible active sites created. The N-doping allowed an increase in the selectivity for the 4-electron process, resulting in a % of H2O2 produced < 25% for Cu/GOE-u (vs. almost 75% for Cu/GOE). Both nanocomposites revealed good tolerance to methanol crossover, and the Cu/GOE-u displayed a moderate long-term electrochemical stability, with current retention of 84% after 20,000 s.

Foliar Application of Cu Nanoparticles Modified the Content of Bioactive Compounds in Moringa oleifera Lam

Moringa oleifera Lam is a plant that has recently gained importance as a food because of its nutritional value and bioactive compound content and because practically all the organs are usable. The use of nanoparticles has appeared as an alternative to increase bioactive compounds in plants. The goal of this work was to determine if the application of copper nanoparticles would increase the content of bioactive compounds and antioxidant capacity in M. oleifera. Copper (Cu) nanoparticles were applied to the leaves at four different times throughout crop growth. The biocompounds were analyzed after the second, third, and fourth applications. The results show that application of Cu nanoparticles has a beneficial effect on the accumulation of bioactive compounds in M. oleifera leaves. In addition, the antioxidant capacity and carotenoid and chlorophyll contents in the leaves of M. oleifera increased after Cu nanoparticles application. The same effect was not observed in the fruit of M. oleifera. Here, the bioactive compound contents diminished. Therefore, the use of Cu nanoparticles can be an important alternative to improve the quality of this plant, particularly that of the leaves.

Foliar Application of Copper Nanoparticles Increases the Fruit Quality and the Content of Bioactive Compounds in Tomatoes

Nanotechnology is a potential and emerging field with multiple applications in different areas of study. The beneficial effects of the use of nanoparticles in agriculture have already been proven. The objective of this research was to determine if the foliar application of Cu nanoparticles (NPs) could increase the content of the bioactive compounds in tomato fruits. Our study considered four treatments with different concentrations of Cu nanoparticles (50, 125, 250, 500 mg L−1, diameter 50 nm) applied twice during the development of the culture. The effects on the fruit quality and the contents of the antioxidant compounds were determined. The application of the Cu nanoparticles induced the production of fruits with greater firmness. Vitamin C, lycopene, and the ABTS antioxidant capacity increased compared to the Control. In addition, a decrease in the ascorbate peroxidase (APX) and glutathione peroxidase (GPX) enzymatic activity was observed, while the superoxide dismutase (SOD) and catalase (CAT) enzymes showed a significant increase. The application of Cu NPs induced a greater accumulation of bioactive compounds in tomato fruits.

Study on the tribological behaviors of copper nanoparticles in three kinds of commercially available lubricants

PurposeThe purpose of this paper is to study the tribological properties of Cu nanoparticles (NPs) as lubricant additives in three kinds of commercially available lubricants.Design/methodology/approachA four-ball machine is used to estimate the tribological properties of Cu NPs as lubricant additives in three kinds of commercially available lubricants. Three-dimensional optical profiler and electrical contact resistance are evaluated to investigate the morphology of the worn surfaces and the influence of Cu NPs on tribofilms.FindingsWear tests show that the addition of Cu NPs as lubricant additives could reduce wear and increase load-carrying capacity of commercially available lubricants remarkably, indicating that Cu NPs have a good compatibility with the existing lubricant additives in commercially available lubricants.Originality/valueThe tribological properties of Cu NPs as lubricant additives in three kinds of commercially available lubricants were investigated in this paper. These results are reliable and can be very helpful for application of Cu NPs as lubricant additives in industry.

Cu Nanoparticles in Hydrogels of Chitosan-PVA Affects the Characteristics of Post-Harvest and Bioactive Compounds of Jalapeño Pepper.

Peppers are consumed all over the world due to the flavor, aroma, and color that they add to food. Additionally, they play a role in human health, as they contain a high concentration of bioactive compounds and antioxidants. The treatments used were an absolute control, Cs-PVA, and four treatments with 0.02, 0.2, 2, and 10 mg (nCu) g−1 (Cs-PVA). The application of Cu nanoparticles in chitosan-PVA hydrogels increases the content of capsaicin by up to 51% compared to the control. This application also increases the content of antioxidants ABTS [2,2′-azino-bis (3-ethylbenzothiazolin-6-sulfonic acid)] and DPPH (2,2-diphenyl-1-picrylhydrazyl), total phenols and flavonoids (4%, 6.6%, 5.9%, and 12.7%, respectively) in jalapeño pepper fruits stored for 15 days at room temperature; under refrigeration, it increases DPPH antioxidants, total phenols, and flavonoids (23.9%, 1.54%, and 17.2%, respectively). The application of Cu nanoparticles in chitosan-PVA hydrogels, even when applied to the substrate, not only has an effect on the development of the jalapeño pepper crop, but also modifies the post-harvest characteristics of the jalapeño pepper fruits.

Growth and enzymatic activity of maize (Zea mays L.) plant: Solution culture test for copper dioxide nano particles

ABSTRACTCopper (Cu) is an essential micronutrient for plants, which acts either as the metal component of enzymes or as a functional structural or a regulatory co-factor of a large number of enzymes. To understand the possible benefits of applying nanotechnology to agriculture, the first step should be to analyze penetration and transport of nano-particles in plants. The present study was conducted to test the hypothesis that copper nanoparticle would enter into the plant cell and govern the growth of maize plant.A solution culture experiment was conducted to investigate the effect of Cu nano-particles (<50nm) on the growth and enzymatic activity of maize (Zea mays L.) plant. Bioaccumulation of Cu nano-particles in plant was also investigated. Results showed that Cu nano-particles can enter into the plant cell through roots and leaves. Bioaccumulation increased with increasing concentration of Cu nano-particles (NPs), and agglomeration of particles was observed in the cells using transmission-electron microscopy. Application of Cu nano-particles through solution culture as well as spray enhanced the growth (51%) of maize plant in comparison to control. The different enzymatic activities like glucose-6-phosphate dehydrogenase, succinate dehydrogenase, superoxide dismutase, catalase, andguaiacol peroxidase were studied to find a possible pathway through which NPs may affect the enzymatic activity of plant. Amongst the enzymes, the activity of glucose-6-phosphate dehydrogenase was highly influenced by copper oxide (CuO)nano-particles application by spray as well as in solution. Experimental results revealed that CuOnano-particles affected the pentose phosphate pathway of maize plant. The obtained experimental results provided conclusive evidence to indicate that the nano-particles considered under this study could enter into the plant cell, easily be assimilated by plants and also enhanced its growth by regulating the different enzyme activities.

Synthesis and tribological properties of oil-soluble copper nanoparticles as environmentally friendly lubricating oil additives

Purpose – The purpose of this paper is to synthesize oil-soluble copper (Cu) nanoparticles modified with free phosphorus and sulfur modifier and investigate its tribological properties as environment-friendly lubricating oil additives. Design/methodology/approach – To improve the anti-oxidation properties of these nanoparticles, two kinds of surface modifiers, oleic acid and oleylamine were used simultaneously. The morphology, composition, structure and thermal properties of as-synthesized Cu nanoparticles were investigated by means of transmission electron microscopy, X-ray powder diffraction, Fourier transform infrared spectrometry and differential thermal and thermogravimetric analysis. The tribological properties of as-synthesized Cu nanoparticles as an additive in liquid paraffin were evaluated with a four-ball friction and wear tester. Findings – It has been found that an as-synthesized Cu nanoparticle has a size of 2-5 nm and can be well dispersed in organic solvents. Tribological properties evaluation results show that as-synthesized Cu nanoparticles possess excellent anti-wear properties as an additive in liquid paraffin. The reason lies in that as-synthesized surface-capped Cu nanoparticles are able to deposit on sliding steel surface and form a low-shearing-strength protective layer thereon, showing promising application as an environmentally acceptable lubricating oil additive, owing to its free phosphorus and sulfur elements characteristics. Originality/value – Oil-soluble surface-modified Cu nanoparticles without phosphorus and sulfur were synthesized and its tribological properties as lubricating oil additives were also investigated in this paper. These results could be very helpful for application of Cu nanoparticles as environment-friendly lubricating oil additives.

Cu Nanoparticles From Evaporation of Cu Granule in a Microwave Torch Plasma at Atmospheric Pressure

The copper (Cu) nanoparticles (Cu-NPs) were obtained directly by evaporation of Cu granules in an atmospheric microwave plasma torch flame with a possibility for direct continuous preparation and mass production of Cu-NPs. The microwave plasma generated in a mixture of nitrogen (N2) and argon (Ar) gases evaporates Cu granules and produces Cu-NPs. This template- and catalyst-free process may be promising for the practical production and application of Cu-NPs.

Application of Cu nanoparticles as N32 base oil additives

Cu nanoparticles as N32 base oil additives are studied in the paper and their structure is characterized by transmission electron microscopy (TEM) and X-ray powder diffraction spectroscopy (XRD). The widely used steel-steel friction system is chosen to test the feasibility and practicality of Cu nanoparticles as bearing lubricant additives. The results show that N32 base oil with 0.5% Cu nanoparticle can improve the test sample contact fatigue life than pure N32 base oil.