Copper-based Nanoparticles Research Articles

Electrochemical Behavior of Single CuO Nanoparticles: Implications for the Assessment of their Environmental Fate.

The electrochemical behavior of copper oxide nanoparticles is investigated at both the single particle and at the ensemble level in neutral aqueous solutions through the electrode-particle collision method and cyclic voltammetry, respectively. The influence of Cl- and NO3- anions on the electrochemical processes occurring at the nanoparticles is further evaluated. The electroactivity of CuO nanoparticles is found to differ between the two types of experiments. At the single-particle scale, the reduction of the CuO nanoparticles proceeds to a higher extent in the presence of chloride ion than of nitrate ion containing solutions. However, at the multiparticle scale the CuO reduction proceeds to the same extent regardless of the type of anions present in solution. The implications for assessing realistically the environmental fate and therefore the toxicity of metal-based nanoparticles in general, and copper-based nanoparticles in particular, are discussed.

Dermal transfer quantification of nanoparticles from nano-enabled surfaces

Engineered nanoparticles are used in various applications due to their unique properties, which have led to their widespread use in consumer products. Silver, titanium, and copper-based nanoparticles (NPs) are a few of the commonly used nanomaterials in surface coatings, mainly due to their biocidal, optical, or photocatalytical properties. The knowledge concerning potential dermal exposure to nanoparticles from nanoparticle-enabled surfaces is currently lacking, partly due to analytical challenges. The aim of this study is to perform dermal wiping tests on nano-enabled surfaces and characterize NP release from keyboard covers and freshly painted surfaces, in terms of mass and number concentration, as well as released particle size distribution through the use of spICP-MS. Three types of NPs were selected for method validation testing, Ag, TiO2, and CuO; and, the particle extraction from wipes was found to be efficient for Ag and CuO, but not for TiO2 particles. Thereafter, potential dermal transfer was tested by wipe sampling for two nanoAg-containing silicon keyboard covers, and wood painted with nanoCuO-containing paint. AgNP release was observed for one of the keyboard cover types, with around 5000 particles/cm2 (corresponding to 0.002 ng/cm2) dislodged from the matrix after 3 wiping events. CuO NP release was 20,000 particles/cm2 (0.885 ng/cm2) from the freshly painted surface, and magnitudes higher after the paint was subjected to wear, reaching 1.4 million particles/cm2 (2.5 ng/cm2). The dermal transfer testing by wipe sampling and analytical approach used in this study demonstrates that wipe testing in combination with spICP-MS analysis can provide both qualitative data in terms of mass and number-based NP release, as well as particle characterization in terms of NP size distribution. Obtaining nano-specific release data can aid in providing a better understanding of dermal exposure to NPs from nano-enabled surfaces.

Electrochemical Reduction of Carbon Dioxide with Nitrogen-Doped Copper Nanoparticles

The applications of copper and copper-based nanoparticles as catalysts have generated a great deal of interest in recent years because copper is inexpensive and earth abundant. However, direct conversion of carbon dioxide to fuels and chemicals remains a grand challenge in electrochemical reduction of CO2. Here we report a simple synthetic strategy on nitrogen-doped copper nanoparticles, and investigate the effect of doping amount on the products of CO2 reduction reaction. When the alkylamine is bound to a copper surface, the scission of C-N bond on the particles surface appears to provide nitrogen source to further react with copper nanoparticles through Ostwald ripening process. Compared to pure copper nanoparticles, nitrogen doping not only improves oxidation resistance, but also facilitates multiple proton and electron transfers to synthesize multicarbon products during CO2 reduction reaction. Furthermore, we envision that such unique doping strategy could be extended to the design of other inorganic nanoparticles for various catalytic applications.

Photocatalytic antibacterial activity of copper-based nanoparticles under visible light illumination

Copper oxide and sulfide nanoparticles after annealing treatment at 400 °Chave been characterized and tested for their bactericidal properties toward Staphylococcus aureus and Escherichia coli under the dark and LED light illuminated conditions. It was found that the nanoparticles with the formation of CuS/Cu2S/CuO nanoheterostructuresexhibited a great capability of killing Staphylococcus aureus and Escherichia coli with or without light illumination. The antibacterial activity of the nanoparticles was demonstrated and simply observed with colony counting method. A mechanism of the antibacterial behaviour had been proposed and elucidated in this work.

Biological Effects of Freshly Prepared and 24-h Aqueous Dispersions of Copper and Copper Oxide Nanoparticles on E. coli Bacteria

Copper and copper oxide nanoparticles are promising candidates for the role of “new antibiotics.” However, characteristics of their effect on microorganisms, depending on the nature of the dispersion medium and the time of storage of suspensions, have not been thoroughly studied, which limits the possibilities of application in practice. A comparative evaluation of the effects of freshly prepared and 24-h suspensions of copper and copper oxide nanoparticles (100 nm in size) on E. coli bacteria using the bioluminescence test is carried out. Distilled water and saline are used as dispersion media; the nanoparticle concentration is 1–0.0001 g/L. Significant differences in the antibacterial properties of freshly prepared suspensions of copper and copper oxide nanoparticles are revealed. Colloidal solutions of copper oxide in all studied concentrations have a significant toxic effect in both types of dispersion media (the survival rate of bacteria is less than 20–40%). An antibacterial effect is observed only at 1 g/L of copper nanoparticles (survival is less than 50%) in fresh aqueous dispersions and at 0.01–1 g/L in solutions based on saline (survival rate is 15–75%); i.e., in this case, the role of the dispersion medium is essential. The storage of solutions for 24 h results in a significant decrease in the toxicity of the colloid systems of copper oxide nanoparticles both in water and saline, while the antibacterial effect of suspensions of copper nanoparticles remains almost the same, regardless of the medium type. These phenomena can be caused by changes in the stability of colloidal systems accompanied by the aggregation of nanoparticles. These results indicate the importance of taking into account the nature of the dispersion medium and the time of storage of suspensions of copper-based nanoparticles for their efficient use as antimicrobial agents.

Development of photoanodes for photoelectrocatalytic solar cells based on copper-based nanoparticles on titania thin films of vertically aligned nanotubes

Titania nanotube (TNT)-array thin films well decorated by copper nanoparticles with average size of 3nm were prepared by spray coating of a solution containing size-controlled Cu0 nanoparticles. The consecutive calcination at 300°C and 450°C leads to the oxidation of these Cu NPs to CuO, with small amounts of Cu2O at the lower calcination temperature, but maintaining the high dispersion. Analogous materials prepared by copper electrodeposition lead to significantly larger Cu NPs. The TNT-array thin film shows significantly enhanced photocurrent (up to about 90%) with respect to a comparable thin film prepared by spin coating using a commercial TiO2 P25 sample. The behavior is similar by applying different filters to cut part of solar light simulator radiation. Particularly, using an UV B/C blocking filter, which permits to pass light in the 350–550nm range, an about two-fold intensification in the current-to-electrical energy conversion (normalized to the same total irradiance) is obtained. The presence of CuO nanoparticles decreases the photocurrent density with respect to the support alone (TNT-array 1h), but enhances the H2 photogeneration rate in the gas-phase photoreactor experiments. The results indicate that in the tested experimental conditions, the main role of CuO nanoparticles is to act as co-catalyst to improve the H2 photogeneration rate rather than to promote charge separation or other effects, which promote the photocurrent density.

Aerobic Benzylic C–H Oxidation on Core–Shell Copper-Based Nanoparticles

Key words copper catalysis - copper ferrate - C–H oxidation - aerobic oxidation - nanoparticles - core–shell structures

Visualizing the Cu/Cu2(O) Interface Transition in Nanoparticles with Environmental Scanning Transmission Electron Microscopy.

Understanding the oxidation and reduction mechanisms of catalytically active transition metal nanoparticles is important to improve their application in a variety of chemical processes. In nanocatalysis the nanoparticles can undergo oxidation or reduction in situ, and thus the redox species are not what are observed before and after reactions. We have used the novel environmental scanning transmission electron microscope (ESTEM) with 0.1 nm resolution in systematic studies of complex dynamic oxidation and reduction mechanisms of copper nanoparticles. The oxidation of copper has previously been reported to be dependent on its crystallography and its interaction with the substrate. By following the dynamic oxidation process in situ in real time with high-angle annular dark-field imaging in the ESTEM, we use conditions ideal to track the oxidation front as it progresses across a copper nanoparticle by following the changes in the atomic number (Z) contrast with time. The oxidation occurs via the nucleation of the oxide phase (Cu2O) from one area of the nanoparticle which then progresses unidirectionally across the particle, with the Cu-to-Cu2O interface having a relationship of Cu{111}//Cu2O{111}. The oxidation kinetics are related to the temperature and oxygen pressure. When the process is reversed in hydrogen, the reduction process is observed to be similar to the oxidation, with the same crystallographic relationship between the two phases. The dynamic observations provide unique insights into redox mechanisms which are important to understanding and controlling the oxidation and reduction of copper-based nanoparticles.

Recent advances in the synthesis of copper-based nanoparticles for metal–metal bonding processes

Abstract This review introduces our study on the development of Cu-based nanoparticles suitable as fillers in the metal–metal bonding process. Colloid solutions of various nanoparticles such as cuprous iodide, cupric oxide (CuO), CuO mixed with silver oxide (Ag 2 O/CuO), cuprous-oxide (Cu 2 O), metallic Cu, plolypyrrole-coated metallic Cu, and metallic Cu containing metallic Ag (Ag/Cu) were prepared by liquid phase processes such as reduction and a salt–base reaction. Metal–metal bonding properties of their powders were evaluated by sandwiching the particle powder between metallic discs, annealing them at a pressure of 1.2 MPa, and measuring the shear strength required for separating the bonded discs. Various particles (above-mentioned), various metallic discs (Cu, Ag, and Ni), various bonding temperatures (250–400 °C), and different atmospheres in bonding (H 2 and N 2 ) were examined to find nanoparticle filler suitable for metal–metal bonding. As a result, it was confirmed that the metallic Cu, the CuO, the Ag 2 O/CuO, and the Ag/Cu particles were suitable for Cu Cu bonding in H 2 , low-temperature Cu Cu bonding in H 2 , Ag Ag bonding in H 2 , and Cu Cu bonding in N 2 , respectively. The metallic Cu particles also had functions of Ag Ag and Ni Ni bondings in H 2 . These results were explained with the particle size, the amount of impurity, and the d -value.

In Situ Measurement of CuO and Cu(OH)2 Nanoparticle Dissolution Rates in Quiescent Freshwater Mesocosms

Recent studies have characterized copper-based nanoparticles (CBNPs) as relatively insoluble, raising potential persistence, accumulation, and toxicological concerns about their long-term application as agricultural pesticides. The dissolution rates of two CBNPs were measured in natural and artificial waters under both saturated and unsaturated conditions with respect to CuO(s) (total Cu, <1 mg/kg). Kocide 3000, an agricultural pesticide formulation with nanoscale Cu(OH)2 particles, rapidly dissolved with an experimental half-life of <8 h in natural water. Copper oxide nanoparticles were longer-lived, with an experimental half-life of 73 h in natural water. In contrast to prior reports of CuONP dissolution, our results suggest that even in moderately alkaline waters, CuO and Cu(OH)2 NPs may persist as particles for days to weeks under quiescent conditions in a freshwater environment.

Copper Nanoparticle Induced Cytotoxicity to Nitrifying Bacteria in Wastewater Treatment: A Mechanistic Copper Speciation Study by X-ray Absorption Spectroscopy.

With the inclusion of engineered nanomaterials in industrial processes and consumer products, wastewater treatment plants (WWTPs) could serve as a major sink for these emerging contaminants. Previous research has demonstrated that nanomaterials are potentially toxic to microbial communities utilized in biological wastewater treatment (BWT). Copper-based nanoparticles (CuNPs) are of particular interest based on their increasing use in wood treatment, paints, household products, coatings, and byproducts of semiconductor manufacturing. A critical step in BWT is nutrient removal through nitrification. This study examined the potential toxicity of uncoated and polyvinylpyrrolidone (PVP)-coated CuO, and Cu2O nanoparticles, as well as Cu ions to microbial communities responsible for nitrification in BWT. Inhibition was inferred from changes to the specific oxygen uptake rate (sOUR) in the absence and presence of Cu ions and CuNPs. X-ray absorption fine structure spectroscopy, with linear combination fitting (LCF), was utilized to track changes to Cu speciation throughout exposure. Results indicate that the dissolution of Cu ions from CuNPs drive microbial inhibition. The presence of a PVP coating on CuNPs has little effect on inhibition. LCF analysis of the biomass combined with metal partitioning analysis supports the current hypothesis that Cu-induced cytotoxicity is primarily caused by reactive oxygen species formed from ionic Cu in solution via catalytic reaction intermediated by reduced Cu(I) species.

ChemInform Abstract: Multicomponent Reactions in Organic Synthesis Using Copper‐Based Nanocatalysts

AbstractReview: [86 refs.

Facile synthesis of highly dispersed and thermally stable copper-based nanoparticles supported on SBA-15 occluded with P123 surfactant for catalytic applications

Here, we show a strategy to control the dispersion, spatial distribution, and stabilization of copper-based nanoparticles on a micro–mesoporous silica support, as well as their impact on the catalytic activity. In this respect, SBA-15 with P123 occluded mesopores was used as host to load, by impregnation, copper-based nanoparticles, whose dispersion was similar to that of the homologous NPs prepared by precipitation on the SBA-15 with open mesoporosity, while the thermal stability was better. The oxide and reduced forms of the catalysts were rigorously characterized by ICP-OES, low- and high-angle XRD, N2 physisorption, HRTEM/EDXS, TPR, in situ XRD, and in situ XPS. Due to their high practical impact, both the oxide and metallic forms of the copper-based NPs were evaluated for catalytic activity in CO oxidation and hydrogenation of cinnamaldehyde, respectively. It was shown that the high dispersion of copper-based NPs and the electron-deficient sites, such as M2+ with high affinity for the CO bond, are responsible for the outstanding catalytic performance of the solids. The paper demonstrates that using a simple impregnation method and a functionalized SBA-15 support, high-performance materials can be obtained avoiding the use of precipitating agents and strict control of the synthesis conditions.

In situ surface functionalization of reverse osmosis membranes with biocidal copper nanoparticles

Biofouling may lead to severe operational challenges that can significantly impair membrane desalination processes. In recent years, copper-based nanoparticles (Cu-NPs) have gained increased attention as a potentially viable anti-biofouling agent in membrane processes, due to their strong antibacterial activity and relatively low cost. This study presents a novel and facile method to attach biocidal Cu-NPs on the surface of a thin-film composite reverse osmosis membrane. Herein, we suggest a method for membrane surface functionalization with Cu-NPs that is performed without disassembling the membrane module, which highlights its practicality and potential application for reverse osmosis desalination plants. The loading of Cu-NPs on the membrane was confirmed both by scanning electron microscope imaging and X-ray photoelectron spectroscopy analysis, indicating that the deposited nanoparticles were composed of either metallic copper or copper-oxide. The impact of the in situ Cu-NP modification on membrane transport properties was found to be minor, with only a slight increase of the water and salt permeability. Furthermore, except for a slight increase in hydrophobicity, the modified membrane exhibited surface properties comparable to those of the pristine membrane. Finally, the in situ formed Cu-NPs imparted a strong antibacterial activity to the membrane surface, leading to 90% reduction in the number of attached live Escherichia coli bacteria on the modified membrane compared to the pristine reverse osmosis membrane. This study demonstrates that in situ grafting of Cu-NPs on reverse osmosis membranes is a potential alternative to reduce biofouling.

Copper-Based Catalysts Supported on Highly Porous Silica for the Water Gas Shift Reaction.

Copper-based nanoparticles, supported on either a silica aerogel or cubic mesostructured silicas obtained by using two different synthetic protocols, were used as catalysts for the water gas shift reaction. The obtained nanocomposites were thoroughly characterised before and after catalysis through nitrogen adsorption-desorption measurements at -196 °C, TEM, and wide- and low-angle XRD. The samples before catalysis contained nanoparticles of copper oxides (either CuO or Cu2 O), whereas the formation of metallic copper nanoparticles, constituting the active catalytic phase, was observed either by using pre-treatment in a reducing atmosphere or directly during the catalytic reaction owing to the presence of carbon monoxide. A key role in determining the catalytic performances of the samples is played by the ability of different matrices to promote a high dispersion of copper metal nanoparticles. The best catalytic performances are obtained with the aerogel sample, which also exhibits constant carbon monoxide conversion values at constant temperature and reproducible behaviour after subsequent catalytic runs. On the other hand, in the catalysts based on cubic mesostructured silica, the detrimental effects related to sintering of copper nanoparticles are avoided only on the silica support, which is able to produce a reasonable dispersion of the copper nanophase.

Dissolution and Persistence of Copper-Based Nanomaterials in Undersaturated Solutions with Respect to Cupric Solid Phases.

Dissolution of copper-based nanoparticles (NPs) can control their environmental persistence and toxicity. Previous research has generally reported limited dissolution of Cu-based NPs at circumneutral pH, but the environmentally important case of dissolution in solutions that are undersaturated with respect to copper mineral phases has not been investigated thoroughly. In this study, immobilized Cu-based NPs were fabricated on solid supports. Metallic copper (Cu), cupric oxide/hydroxide (Cuox), and copper sulfide (CuxS) NPs were investigated. Dissolution rate constants were measured in situ by an atomic force microscope equipped with a flow-through cell. A mass-balance model indicated that the flowing solution was consistently undersaturated with respect to cupric solid phases. Based on the measured rate constants, Cuox NPs are expected to dissolve completely in these undersaturated conditions within a matter of hours, even at neutral to basic pH. The expected persistence of metallic Cu NPs ranges from a few hours to days, whereas CuxS NPs showed no significant dissolution over the time scales studied. Field deployment of Cu-based NP samples in a freshwater stream confirmed these conclusions for a natural aquatic system. These results suggest that Cu and Cuox NPs will be short-lived in the environment unless dissolution is hindered by a competing process, such as sulfidation.

GC-TOF-MS based metabolomics and ICP-MS based metallomics of cucumber (Cucumis sativus) fruits reveal alteration of metabolites profile and biological pathway disruption induced by nano copper

Copper-based nanoparticles have wide application in agriculture as fungicides and bactericides.

Copper-based nanoparticles prepared from copper (II) acetate bipyridine complex

We report the synthesis of CuO, Cu/Cu2O and Cu2O/CuO nanoparticles (NPs) from the single copper (II) acetate bipyridine complex by three different methods:microwave-assisted, solvothermal and borohydride. Presence of bipyridine ligand in the copper complex would impose no need in additional stabilization during synthesis. The phases of formed NPs were identified by X-ray diffraction. CuO NPs of ~11 nm were obtained via solvothermal synthesis from alkaline solution at 160?C. The Cu/Cu2O NPs of ~80 nm were produced via microwave-assisted polyol procedure at 185-200?C, where ethylene glycol can play a triple role as a solvent, a reducing agent and a surfactant. The Cu2O/CuO NPs of ~16 nm were synthesized by a borohydride method at room temperature. Interplanar spacing calculated from the selected-area electron diffraction data confirmed the formation of Cu, CuO and Cu2O phases in respective samples. All NPs are stable and can be used for various applications including biomedicine.

ДОСЛІДЖЕННЯ ГОСТРОЇ ТОКСИЧНОСТІ КОН'ЮГАТУ НАНОЧАСТИНОК МІДІ З ЦЕФТРІАКСОНОМ ПРИ ВНУТРІШНЬОШЛУНКОВОМУ ВВЕДЕННІ МИШАМ

&lt;p&gt;&lt;strong&gt;ACUTE ORAL TOXICITY TESTING OF THE COPPER NANOPARTICLE-CEFTRIAXONE CONJUGATE IN MICE&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;&lt;strong&gt;P.V. Simonov&lt;/strong&gt;&lt;/p&gt;&lt;p&gt;Bogomolets National Medical University, Kyiv&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Summary:&lt;/strong&gt; The antimicrobial resistance of causative agents of infectious diseases problem may be solved by an introduction of medications based on metal nanoparticles and their combinations with other antimicrobial drugs into medical practice. The results on a determination of the copper nanoparticle-ceftriaxone conjugate acute toxicity parameters in an experiment of oral administration in BALB/с mice were presented in the article. It had been found out that the studied substance belonged to the 5&lt;sup&gt;th&lt;/sup&gt; toxicity class (practically non-toxic). Central and autonomous nervous systems, gastro-intestinal tract and kidneys were the biological targets of action of the copper nanoparticle-ceftriaxone conjugate after oral administration in mice. A reversibility of the studied substance’s negative influence on animals was confirmed by an absence of significant influence on a dynamics of body mass changes. It seems advisable to continue studies on the copper nanoparticle-ceftriaxone conjugate in order to introduce it into medical practice for a treatment of infections, particularly those caused by antimicrobial resistant strains.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Key words (MeSH Terms):&lt;/strong&gt; Metal Nanoparticles; Copper; Ceftriaxone; Safety; Toxicity Tests, Acute; Administration, Oral; Mice.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Introduction.&lt;/strong&gt; The antimicrobial resistance of causative agents of community- and hospital-acquired infections is a global healthcare problem nowadays. It may be solved by an introduction of new antimicrobial medications, which are effective against resistant strains of bacteria and fungi, into medical practice. Copper-based nanoparticles may become such novel drugs.&lt;/p&gt;&lt;p&gt;It seems advisable to develop a medication based on the copper nanoparticle-ceftriaxone conjugate. It would comprise a composition of a safe and efficient cephalosporin antibiotic with copper, which is an essential trace element for a human organism and possesses wide spectrum of antimicrobial action, especially in a nanostructured form.&lt;/p&gt;&lt;p&gt;The purpose of this study was to determine acute oral toxicity parameters of the copper nanoparticle-ceftriaxone conjugate in laboratory female BALB/с mice.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Methods.&lt;/strong&gt; Pharmacological, toxicological, pathomorphological, and statistical methods were used to achieve the goals and objectives of the study.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Results and discussion&lt;/strong&gt;. The conjugate consisting of 20 nm chemically stable spherical zerovalent copper nanoparticles, obtained by original protocol of chemical condensation in aqueous solution method, and ceftriaxone, a third generation cephalosporin, belongs to the 5&lt;sup&gt;th&lt;/sup&gt; toxicity class (practically non-toxic) according to K. K. Sidorov classification in an experiment of single oral administration in laboratory female BALB/с mice.&lt;/p&gt;&lt;p&gt;Central and autonomous nervous systems, gastro-intestinal tract and kidneys are the biological targets of action of the copper nanoparticle-ceftriaxone conjugate after oral administration in mice.&lt;/p&gt;&lt;p&gt;A reversibility of the copper nanoparticle-ceftriaxone conjugate’s toxic influence on animals after single oral administration is confirmed by an absence of significant influence on a dynamics of body mass changes.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Conclusions.&lt;/strong&gt; The copper nanoparticle-ceftriaxone conjugate appears to be a safe substance after single oral administration in laboratory female BALB/с mice, according to results obtained. It seems advisable to continue studies on the substance in order to introduce it into medical practice for a treatment of infections, particularly those caused by antimicrobial resistant strains.&lt;/p&gt;

Fabrication and Characterization of Copper-Based Nanoparticles for Transparent Solar Cell Applications.

This paper reports on the fabrication of copper-based nanoparticles using microemulsions, and their optical properties for use in transparent solar cell applications. Microemulsions, containing pure copper nanoparticles, were prepared using the reaction process of CuCl2 with KBH4. We have confirmed that various sized copper nanoparticles, with a radius of up to 10 nm, form within an aqueous concentration of CuCl2 ≤ 2.0 M. Using microstructural observation, we found that parts of pure copper nanoparticles, synthesized in microemulsions, oxidize into cuprous oxide and agglomerate with one another in a normal atmosphere. The copper-based particles were then transferred to substrates by using a spin-coating process. Variations in spin speed led to significant changes in the transmittance and reflectance of the spin-coated particles. Transparent and anti-reflective properties of the particles were obtained at an optimum condition of spin speed. This suggests that the fabrication of the copper-based nanoparticles can be effectively applied to the manufacturing of transparent solar cells.