Interaction Of Copper Nanoparticles Research Articles

Metal-Support Interactions in Heterogeneous Catalysis: DFT Calculations on the Interaction of Copper Nanoparticles with Magnesium Oxide.

Oxide supports play an important role in enhancing the catalytic properties of transition metal nanoparticles in heterogeneous catalysis. How extensively interactions between the oxide support and the nanoparticles impact the electronic structure as well as the surface properties of the nanoparticles is hence of high interest. In this study, the influence of a magnesium oxide support on the properties of copper nanoparticles with different size, shape, and adsorption sites is investigated using density functional theory (DFT) calculations. By proposing simple models to reduce the cost of the calculations while maintaining the accuracy of the results, we show using the nonreducible oxide support MgO as an example that there is no significant influence of the MgO support on the electronic structure of the copper nanoparticles, with the exception of adsorption directly at the Cu-MgO interface. We also propose a simplified methodology that allows us to reduce the cost of the calculations, while the accuracy of the results is maintained. We demonstrate in addition that the Cu nanowire model corresponds well to the nanoparticle model, which reduces the computational cost even further.

Properties of Nanocomposites of High-Pressure Polyethylene with Metal-Containing Nanofillers

The effect of nanofiller (NF) additives containing copper oxide nanoparticles (NPs) stabilized by a polymer matrix of maleated polyethylene (MAPE), obtained by the mechanochemical method, on the properties of composites based on high-pressure polyethylene (LDPE) has been investigated by X-ray diffraction (XRD) and thermographic (TGA) analysis. The improvement in strength, deformation, and rheological properties, as well as the thermo-oxidative stability of the obtained nanocomposites, has been revealed, which is associated with the synergistic effect of the interaction of copper nanoparticles with maleic groups of MAPE. It has been shown that LDPE-based nanocomposites can be processed both by pressing and by injection molding and extrusion, which expands the scope of its application.

D-penicillamine modified copper nanoparticles for fluorometric determination of histamine based on aggregation-induced emission.

A fluorometric method for the determination of histamine has been developedbased on aggregation-induced emission (AIE) effect of D-penicillamine capped copper nanoparticles (DPA-CuNPs). The fluorescent DPA-CuNPs were synthesized by a one-pot method using D-penicillamine as both reducing agent and stabilizing ligand. The size, morphology and physical chemical properties of DPA-CuNPs were examined by transmission electron microscopy (TEM), fluorescence spectroscopy, fourier transform infrared spectroscopy (FTIR) and absorption spectroscopy. The DPA-CuNPs exhibit AIE effect and show intense red fluorescence (650nm). In the presence of histamine, DPA-CuNPs are dispersed into small homogeneous particles, causing fluorescence quenching. Based on this reaction, a histamine sensor is constructed. The fluorescence of the CuNPs solution has a good linear relationship with histamine concentration in the range 0.05μM to 5μM and the determination limit (3σ/slope) is 30nM. The estimated method was successfully applied to the determination of histamine in fish, pork and red wine. Graphical abstract Schematic representation of copper nanoparticles for histamine analysis. In the presence of histamine, the strong red fluorescence of copper nanoparticles is obvious decreased through interaction of copper nanoparticles and histamine.

Spectroscopic and Computational Analysis of Protein Binding on Copper Nanoparticles: an Insight into Ligand and Nanocarrier Interaction

The interaction of copper nanoparticles (CuNP) with bovine serum albumin (BSA) under physiological conditions was studied using spectroscopic techniques. The analysis of the adsorption of BSA by CuNP indicated that it followed the Langmuir adsorption isotherm and a pseudo second-order expression. The quenching of BSA intrinsic fluorescence was observed upon its binding to CuNP. The calculation of a modified Stern–Volmer constant revealed that the binding of CuNP to BSA complies with the static mechanism. The binding constant, the binding site, and the thermodynamic parameters of the BSA–CuNP interaction were evaluated using fluorescence quenching data at 298, 310, and 333 K. The binding constant decreased with increase in temperature, and the binding of BSA to CuNP involved one single site. Negative free energy (ΔG), positive enthalpy (ΔH), and entropy change (ΔS) calculations suggested that the binding of BSA to CuNP was spontaneous and hydrophobic forces played a key role in stabilizing the complex. An evaluation of the Hill coefficient indicated negative cooperativity. Minor conformational changes were observed in the circular dichroism spectra when BSA was bound to CuNP.

Study of the Interaction of Copper Nanoparticles with Titanium in Landfill Soils Layers

The nanotechnology has spread out for every field of the sciences and engineering with applications covering the variety of human and life activities. The TiO2 nanoparticles are of special interest due to the wide range of applications from cosmetics to paint and new applications have continuously been searched. However, the effect of these particles into the environment need detailed investigation since some deleterious effects on the ecosystems have been observed. Among the nanoparticles found in natural soils the copper plays important role due to their strong interactions with the other materials. In this paper, the influence of nanoparticles of copper (NPCu) in the behavior of NPTiO2 were investigated. A normalized experimental procedure on the soil column was carried out with soil impregnated by copper nanoparticles and compared with the natural soil. Stable solutions of water and NPTiO2 were prepared and used to carried out the column percolation experiments with the concentrations of NPTiO2 measured at the inlet and outlet of the solutions. The results indicated that the TiO2 nanoparticles can mediate transport of Cu in some soil environments. Suggested that decreases in Cu transport were mainly due to increased desorption.

Copper sols stabilized by poly(ethylene glycol-600-monolaurate) and its complexes with poly(acrylic acid)

Copper sols stabilized by a polymer-colloid complex are studied via dynamic light scattering and transmission electron microscopy. It is shown that the polymer-colloid complex including poly(acrylic acid) and the nonionogenic polymeric surfactant poly(ethylene glycol-600-monolaurate) is an effective protector of copper nanoparticles formed via the reduction of Cu2+ ions in an aqueous medium. The sizes of sol particles of the nanocomposite consisting of the polymer-colloid complex and copper nanoparticles depend on the method of preparation of the nanocomposite. The incorporation of the copper nanoparticles being formed (an average diameter of 5 nm) into particles of the polymer-colloid complex leads to an insignificant change in the sizes of the complex particles. The same sizes are typical for particles of the nanocomposite formed during the introduction of surfactant micelles in the copper sol formed in the solution of poly(acrylic acid). The interaction of copper nanoparticles formed in an aqueous medium with surfactant micelles entails their aggregation; as a result, these nanoparticles turn out to be incorporated into large aggregates with equivalent radii of up to 100 nm. When poly(acrylic acid) is incorporated into this sol, the sizes of its particles insignificantly change apparently because of the low rate of structural rearrangements accompanying the formation of the polymer-colloid complex.

Investigations into the antibacterial behavior of copper nanoparticles against Escherichia coli

Zerovalent copper nanoparticles (Cu0) of 12 nm size were synthesized using an inert gas condensation method in which bulk copper metal was evaporated into an inert environment of argon with subsequent cooling for nucleation and growth of nanoparticles. Crystalline structure, morphology and estimation of size of nanoparticles were carried out by X-ray diffraction and transmission electron microscopy. The antibacterial activity of these nanoparticles against the Gram-negative bacterium Escherichia coli was assessed in liquid as well as solid growth media. It was observed from scanning electron microscopic analysis that the interaction of copper nanoparticles with E. coli resulted in the formation of cavities/pits in the bacterial cell wall. The antibacterial property of copper nanoparticles was attributed mainly to adhesion with bacteria because of their opposite electrical charges, resulting in a reduction reaction at the bacterial cell wall. Nanoparticles with a larger surface-to-volume ratio provide more efficient means for antibacterial activity.

Interaction of copper nanoparticles with liposomes

The reduction of copper(II) ions in an aqueous dispersion of positively charged liposomes results in the formation of stable sols of a complex of copper nanoparticles with the surface of liposomes. The mean size (7 nm) and the narrow size distribution of metal nanoparticles are similar to those observed in the case of metal sol formation in polymer solutions. The labile character of bonds between nanoparticles and liposomes makes the latter able to compete with a linear polymer (poly-N-vinylpyrrolidone) in binding to nanoparticles. This ability is manifested in the independence of an almost even distribution of nanoparticles between these competitors from the sol preparation mode in a system including both poly(N-vinylpyrrolidone) macromolecules and liposomes. The evenness of the distribution indicates an approximately identical stability of complexes of copper nanoparticles with both competitors. The replacement of liposomes with poly(N-vinylpyrrolidone) macromolecules in the protective shields of nanoparticles is accompanied by the detachment of the nanoparticles from the surface, thereby allowing the measurement of their size and size distribution in the case where such measurements are impossible because of a high density of nanoparticles on the liposome surface.