Observation of charge stripes in cupric oxide

Dual Studies of Photo Degradation and Adsorptions of Congo Red in Wastewater on Graphene-Copper Oxide Heterostructures

This work comprehensively studies both the photocatalytic degradation and the adsorption process of Congo red dye on the surface of a mixed-phase copper oxide-graphene heterostructure nanocomposite. Laser-induced pristine graphene and graphene doped with different CuO concentrations were used to study these effects. Raman spectra showed a shift in the D and G bands of the graphene due to incorporating copper phases into the laser-induced graphene. The XRD confirmed that the laser beam was able to reduce the CuO phase to Cu₂O and Cu phases, which were embedded into the graphene. The results elucidate incorporating Cu₂O molecules and atoms into the graphene lattice. The production of disordered graphene and the mixed phases of oxides and graphene were validated by the Raman spectra. It is noted from the spectra that the D site changed significantly after the addition of doping, which indicates the incorporation of Cu₂O in the graphene. The impact of the graphene content was examined with 0.5, 1.0, and 2.0 mL of CuO. The findings of the photocatalysis and adsorption studies showed an improvement in the heterojunction of copper oxide and graphene, but a significant improvement was noticed with the addition of graphene with CuO. The outcomes demonstrated the compound's potential for photocatalytic use in the degradation of Congo red.

Copper oxide (CuO) and manganese oxide (MnO) nanoparticles induced biomass accumulation, antioxidants biosynthesis and abiotic elicitation of bioactive compounds in callus cultures of Ocimum basilicum (Thai basil)

Nano-elicitation is one among the prioritised strategies considered globally for sustainable and uniform production of industrially important medicinal compounds. Ocimum basilicum (Thai basil), a renowned medicinal species is a reservoir of commercially vital metabolites and proved for its health assuring effects in cancer, diabetes, microbial and cardiovascular diseases. However, its consumption and industrial demand raised intent to divert towards better alternates for ensuring sustainable production of medicinal compounds. Herein, we investigated the comparative potential of metal oxide [copper oxide (CuO) and manganese oxide (MnO)] nanoparticles to elicit the biosynthesis of bioactive metabolites and antioxidative capacity of O.basilicum callus cultures. Results showed that callus grown on MS media supplemented with 10 mg/L CuO-NPs resulted in the highest biomass accumulation (FW: 172.8 g/L, DW: 16.7 g/L), phenolic contents (TPC: 27.5 mg/g DW), and flavonoid contents (TFC: 9.1 mg/g DW) along with antioxidant activities (DPPH: 94%, ABTS: 881 μM TEAC, FRAP: 386 μM TEAC) compared with MnO-NPs and control. Likewise, the Superoxide dismutase (SOD: 1.28 nM/min/mg FW) and Peroxidase (POD: 0.48 nM/min/mg FW) activities were also recorded maximum in CuO-NPs elicited cultures than MnO-NPs and control. Moreover, the HPLC results showed that rosmarinic acid (11.4 mg/g DW), chicoric acid (16.6 mg/g DW), eugenol (0.21 mg/g DW) was found optimum in cultures at 10 mg/L CuO-NPs. Overall, it can be concluded that CuO nanoparticles can be effectively used as a elicitor for biosynthesis of metabolites in callus cultures of O. basilicum (Thai basil). The study is indeed a contribution to the field that will help decoding the mechanism of action of CuO NPs. However, further molecular investigations are needed to fully develop understanding about the metabolic potential of O. bascillicum and scalling up this protocol for bulkup production of bioactive compounds.

Algae-meditated route to cuprous oxide (Cu2O) nanoparticle: differential expression profile of MALAT1 and GAS5 LncRNAs and cytotoxic effect in human breast cancer

Background

Breast cancer (BC), as the most widely recognized disease in women worldwide, represents about 30% of all cancers impacting women. This study was aimed to synthesize Cu2O nanoparticles from the cystoseira myrica algae (CM-Cu2O NPs) assess their antimicrobial activity against pathogenic bacteria and fungi. We evaluated the expression levels of lncRNAs (MALAT1 and GAS5) and apoptosis genes (p53, p27, bax, bcl2 and caspase3), their prognostic roles.

Methods

In this study, CM-Cu2O NPs synthesized by cystoseira myrica algae extraction used to evaluate its cytotoxicity and apoptotic properties on MDA-MB-231, SKBR3 and T-47D BC cell lines compared to HDF control cell line. The CM-Cu2O NPs was characterized by UV–Vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Transmission electron microscopy (TEM) and Scanning electron microscopy (SEM). The antimicrobial activity of CM-Cu2O NPs was assessed against pathogenic bacteria, staphylococcus aureus (S. aureus) PTCC 1112 bacteria as a standard gram-positive bacteria and pseudomonas aeruginosa (P. aeruginosa) PTCC 1310 as a standard gram-negative bacterium. Expression profile of MALAT1 and GAS5 lncRNAs and apoptosis genes, i.e., p27, bax, bcl2 and caspase3 genes, were calculated utilizing qRT-PCR. The changes in the expression levels were determined using the DDCT method.

Results

MALAT1 was upregulated in MDA-MB-231, SKBR3 and T-47D BC (p < 0.01), while GAS5 was downregulated in SKBR3 and T-47D cell lines tested compared with HDF control cell line (p < 0.05) was found. The results revealed that, p27, bax and caspase3 were significantly upregulated in BC cell lines as compared with normal cell line. Bcl2 expression was also significantly increased in MDA-MB-231 and T47D cell lines compared with normal cell line, but bcl2 levels were downregulated in SKBR3 cell line.

Conclusions

Our results confirm the beneficial cytotoxic effects of green-synthesized CM-Cu2O NPs on BC cell lines. This nanoparticle decreased angiogenesis and induces apoptosis, so we conclude that CM-Cu2O NPs can be used as a supplemental drug in cancer treatments. Significantly, elevated circulating lncRNAs were demonstrated to be BC specific and could differentiate BC cell lines from the normal cell lines. It was demonstrated that lncRNAs used in this study and their expression profiles can be created as biomarkers for early diagnosis and prognosis of BC. Further studies utilizing patients would give recognizable identification of lncRNAs as key players in intercellular interactions.

Current status of plant metabolite-based fabrication of copper/copper oxide nanoparticles and their applications: a review

Since green mode of nanoparticles (NPs) synthesis is simple, advantageous and environment friendly relative to chemical and physical procedures, various plant species have been used to fabricate copper and copper oxide nanoparticles (Cu/CuO-NPs) owing to the presence of phytochemicals which often act as capping as well as stabilizing agent. These Cu/CuO-NPs are highly stable and used in the degradation of organic dyes like methylene blue and reduction of organic compounds such as phenols. They are also used as antibacterial, antioxidant and antifungal agent due to their cytotoxicity. They are also examined for agricultural crops growth and productivity. Cu-NPs increased the root and shoot growth of mung bean. In wheat plants, these particles reduced shoot growth; and enhanced the grain yield and stress tolerance through starch degradation. Similarly, CuO-NPs treated seedlings have shown reduced chlorophyll, carotenoid and sugar content, whereas proline and anthocyanins were increased in Brassica rapa seedlings. Overall, this review presents the recent understanding of plant-mediated Cu and CuO-NPs fabrication and their application in biomedicine, environmental remediation and agricultural practices. A comparison of the traditional/conventional method of fabrication of NPs with those of green protocols has also been made. Some misconception of copper chemistry has also been critically discussed in terms of oxidation and reduction reactions.

Electrical, structural, and photocatalytic properties of copper oxide nanowire

Using a direct oxidation method in a horizontal quartz tube, copper oxide nanowires are grown on a Cu substrate. In order to investigate the growth temperature effects on the structural, morphological, electrical, and photocatalytic properties of the copper oxide nanowires, X-ray diffraction, scanning electron microscopy, a KEITHLEY 2361 system, and a homemade photoreactor are used. The X-ray diffraction results show that both CuO and Cu2O phases are formed, and while increasing the growth temperature, the crystallinity is improved and the intensity of most of the diffraction peaks increases. The scanning electron microscopy images at different growth temperatures show that the number, density, and length of the copper oxide nanowires on pre-formed micro-scaled grains increase, when the growth temperature increases to 700°C and sharper nanowires with average diameters of 1–3 µm grow on the surface. Also I–V curves show that by raising the growth temperature, the conductivity of the samples increases. In addition, the photocatalytic activities are studied by photocatalytic degradation of Congo red dye, and based on these results, the sample grown at 700°C with the highest number and density of the nanowires showed the best photocatalytic performance and electrical conductivity. The results can be used to guide better understanding of the growth behavior of copper oxide nanowires and can be useful for the development of novel photocatalytic nanodevices.

Copper Oxide/Hydroxide Nanomaterial Synthesized from Simple Copper Salt

The copper oxide, CuO, and copper hydroxide, Cu(OH)2 nanomaterials have been prepared by a simple copper salt aqueous solution reaction. The powder X-ray diffraction (XRD) analysis showed the successful formation of Cu(OH)2 and CuO nanoparticles. The average crystallite size of these Cu(OH)2 and CuO nanoparticles was estimated and found to be around 17[Formula: see text]nm (Cu(OH)2) and 10[Formula: see text]nm (CuO). The surface morphology and size of the CuO particles were confirmed by Scanning Electron Microscope (SEM) and High-resolution transmission electron microscope (HRTEM). The Raman analysis, dielectric and conductivity of CuO nanoparticles have been performed. The frequency variation of the capacitance (real dielectric constant) and dielectric loss was studied. The capacitance of the CuO nanoparticles is high at low frequencies and decreases rapidly when the frequency is increased. The frequency dependent ac conductivity follows Johnscher’s power law.

Comparative in situ ROS mediated killing of bacteria with bulk analogue, Eucalyptus leaf extract (ELE)-capped and bare surface copper oxide nanoparticles

This study demonstrates a simple one-pot green method for biosynthesis of terpenoids encapsulated copper oxide nanoparticles (CuONPs) using aqueous leaf extract of Eucalyptus globulus (ELE), as reducing, dispersing, and stabilizing agent. Indeed, the greater attachment and internalization of ELE-CuONPs in Gram-positive and -negative biofilm producing clinical bacterial isolates validated the hypothesis that terpenoids encapsulated CuONPs are more stable and effective antibacterial and antibiofilm agent vis-à-vis commercially available nano and micro sized analogues. Gas chromatography-mass spectroscopy (GC-MS) analysis of pristine ELE identified 17 types of terpenoids based on their mass-to-charge (m/z) ratios. Amongst them four bioactive terpenoids viz. terpineols, 2,6-octadienal-3,7-dimethyl, benzamidophenyl-4-benzoate and β-eudesmol were found associated with the CuONPs as ELE-cap, and most likely involved in the nucleation and stabilization of ELE-CuONPs. Further, the Fourier transformed infrared (FTIR) analysis of ELE-CuONPs also implicated other functional biomolecules like proteins, sugars, alkenes, etc. with ELE terpenoids corona. Flow cytometric (FCM) data exhibited significantly enhanced intracellular uptake propensity of terpenoids encapsulated ELE-CuONPs and accumulation of intracellular reactive oxygen species (ROS), which ensued killing of planktonic cells of extended spectrum β-lactamases (ESβL) producing Escherichia coli-336 (E. coli-336), Pseudomonas aeruginosa-621 (P. aeruginosa-621) and methicillin-resistant Staphylococcus aureus-1 (MRSA-1) clinical isolates compared to the bare surface commercial nano-CuO and bulk sized CuO. The study for the first-time demonstrated the (i) differential bio-nano interface activities due to ELE surface and varied cell wall composition of test bacterial isolates, (ii) antibacterial effect and biofilm inhibition due to disruption of proteins involved in adhesion and biofilm formation triggered by CuONPs induced intracellular oxidative stress, and (iii) indigenous terpenoids-capped bio-inspired CuONPs are more stable and effective antibacterial and antibiofilm agent as compared with commercially available nano-CuO and bulk-CuO.

Excellent peroxidase mimicking property of CuO/Pt nanocomposites and their application as an ascorbic acid sensor

Due to low cost and high stability, the applications of inorganic nanomaterials as efficient alternatives to natural enzymes are drawing much attention. In this work, novel CuO/Pt nanocomposites with high peroxidase-like activity were designed and applied for the colorimetric detection of ascorbic acid (AA). The nanocomposites were prepared by decorating Pt NPs on the surface of CuO nanosheets, which displayed good uniformity and showed improved distribution and stability. The catalytic activity of the prepared CuO/Pt nanocomposites was tested against various chromogenic substrates in the presence of H₂O₂, which displayed efficient peroxidase-like activity and high catalytic stability against temperature. The catalytic mechanism of the CuO/Pt nanocomposites was investigated by hydroxyl radical detection. The peroxidase-like activity decreased significantly in the presence of AA. On the basis of the inhibition property, a colorimetric biosensor was constructed by using the CuO/Pt nanocomposites for the detection of AA. It showed a high selectivity against amino acids, carbohydrates and normal ions. Thus, this work provides new insights into the application of inorganic nanocomposite-based nanozymes in the biosensing field.

Biosynthesis and characterization of copper oxide nanoparticles and its anticancer activity on human colon cancer cell lines (HCT-116)

The eco-friendly synthesis of nanoparticles through green route from plant extracts have renowned a wide range of application in the field of modern science, due to increased drug efficacy and less toxicity in the nanosized mediated drug delivery model. In the present study, our research groups have biosynthesized the stable and cost effective copper oxide nanoparticles (CuO NPs) from the leaves of (Ormocarpum cochinchinense) O. cochinchinense. The synthesis of crystalline CuO NPs from the leaf extract of O. cochinchinense were confirmed by various analytical techniques like UV-Visible Spectroscopy (UV-Vis), Fourier-Transform Infrared Spectroscopy (FT-IR), X-Ray Diffractometer (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Selected Area Electron Diffraction (SAED) pattern. Further the synthesized CuO NPs were screened for anticancer activity on human colon cancer cell lines (HCT-116) by MTT (3-(4,5-dimethyl-2-tiazolyl)-2,5-diphenyl-2-tetrazolium bromide) assay. The obtained result inferred that the synthesized CuO NPs demonstrated high anticancer cytotoxicity on human colon cancer cell lines (HCT-116) with IC₅₀ value of 40μgmL^-1 were discussed briefly in this manuscript.

High Pressure Experimental Studies on CuO: Indication of Re-entrant Multiferroicity at Room Temperature

We have carried out detailed experimental investigations on polycrystalline CuO using dielectric constant, dc resistance, Raman spectroscopy and X-ray diffraction measurements at high pressures. Observation of anomalous changes both in dielectric constant and dielectric loss in the pressure range 3.7–4.4 GPa and reversal of piezoelectric current with reversal of poling field direction indicate to a change in ferroelectric order in CuO at high pressures. A sudden jump in Raman integrated intensity of A_g mode at 3.4 GPa and observation of Curie-Weiss type behaviour in dielectric constant below 3.7 GPa lends credibility to above ferroelectric transition. A slope change in the linear behaviour of the A_g mode and a minimum in the FWHM of the same indicate indirectly to a change in magnetic ordering. Since all the previous studies show a strong spin-lattice interaction in CuO, observed change in ferroic behaviour at high pressures can be related to a reentrant multiferroic ordering in the range 3.4 to 4.4 GPa, much earlier than predicted by theoretical studies. We argue that enhancement of spin frustration due to anisotropic compression that leads to change in internal lattice strain brings the multiferroic ordering to room temperature at high pressures.

Microwave synthesis of 3D rambutan-like CuO and CuO/reduced graphene oxide modified electrodes for non-enzymatic glucose detection

Illustration of the glucose biosensing mechanism based on CuO/r-GO composites.

A new sensing platform based on electrospun copper oxide/ionic liquid nanocomposite for selective determination of risperidone

A copper oxide nanoparticle/ionic liquid nanocomposite modified electrode exhibits excellent electrocatalytic activity towards the oxidation of risperidone.

Biogenic copper oxide nanoparticles synthesis using Tabernaemontana divaricate leaf extract and its antibacterial activity against urinary tract pathogen

This investigation explains the biosynthesis and characterization of copper oxide nanoparticles from an Indian medicinal plant by an eco-friendly method. The main objective of this study is to synthesize copper oxide nanoparticles from Tabernaemontana divaricate leaves through a green chemistry approach. Highly stable, spherical copper oxide nanoparticles were synthesized by using 50% concentration of Tabernaemontana leaf extract. Formation of copper oxide nanoparticles have been characterized by UV-Vis absorption spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) with energy dispersive X-ray analysis (EDX) and transmission electron microscopy (TEM) analysis. All the analyses revealed that copper oxide nanoparticles were 48±4nm in size. Functional groups and chemical composition of copper oxide were also confirmed. Antimicrobial activity of biogenic copper oxide nanoparticles were investigated and maximum zone of inhibition was found in 50μg/ml copper oxide nanoparticles against urinary tract pathogen (Escherichia coli).

Temperature dependence of crystal field excitations in CuO

We report a study on the temperature dependence of charge-neutral crystal field (dd) excitations in cupric oxide, using nonresonant inelastic x-ray scattering spectroscopy. Thanks to a very high-energy resolution (ΔE = 60 meV), we observe thermal effects on the dd excitation spectrum fine structure between temperatures of 10-320 K. The spectra broaden considerably with increasing temperature, consistently with an enhancement of the coupling between crystal field excitations and the temperature-dependent continuum of states above the band gap. We discuss this and other mechanisms that may explain this temperature dependence.

A reaction cell for time-resolved in situ XAS studies during wet chemical synthesis: the Cu2(OH)3Cl case

The use of in situ time-resolved dispersive X-ray absorption spectroscopy (DXAS) to monitor the formation of Cu2(OH)3Cl particles in an aqueous solution is reported. The measurements were performed using a dedicated reaction cell, which enabled the evolution of the Cu K-edge X-ray absorption near-edge spectroscopy to be followed during mild chemical synthesis. The formed Cu2(OH)3Cl particles were also characterized by synchrotron-radiation-excited X-ray photoelectron spectroscopy, X-ray diffraction and scanning electron microscopy. The influence of polyvinylpyrrolidone (PVP) on the electronic and structural properties of the formed particles was investigated. The results indicate clearly the formation of Cu2(OH)3Cl, with or without the use of PVP, which presents very similar crystalline structures in the long-range order. However, depending on the reaction, dramatic differences were observed by in situ DXAS in the vicinities of the Cu atoms.

Synthesis of novel CuO nanosheets and their non-enzymatic glucose sensing applications

In this study, we have developed a sensitive and selective glucose sensor using novel CuO nanosheets which were grown on a gold coated glass substrate by a low temperature growth method. X-ray differaction (XRD) and scanning electron microscopy (SEM) techniques were used for the structural characterization of CuO nanostructures. CuO nanosheets are highly dense, uniform, and exhibited good crystalline array structure. X-ray photoelectron spectroscopy (XPS) technique was applied for the study of chemical composition of CuO nanosheets and the obtained information demonstrated pure phase CuO nanosheets. The novel CuO nanosheets were employed for the development of a sensitive and selective non-enzymatic glucose sensor. The measured sensitivity and a correlation coefficient are in order 5.20 × 10² µA/mMcm² and 0.998, respectively. The proposed sensor is associated with several advantages such as low cost, simplicity, high stability, reproducibility and selectivity for the quick detection of glucose.

Aloe barbadensis Miller mediated green synthesis of mono-disperse copper oxide nanoparticles: optical properties

In this paper, we report on the synthesis of nanostructured copper oxide particles by both chemical and biological method. A facile and efficient synthesis of copper oxide nanoparticles was carried out with controlled surface properties via green chemistry approach. The CuO nanoparticles synthesized are monodisperse and versatile and were characterized with the help of UV-Vis, PL, FT-IR, XRD, SEM, and TEM techniques. The particles are crystalline in nature and average sizes were between 15 and 30 nm. The morphology of the nanoparticles can be controlled by tuning the amount of Aloe vera extract. This new eco-friendly approach of synthesis is a novel, cheap, and convenient technique suitable for large scale commercial production and health related applications of CuO nanoparticles.

Enhanced chemiluminescence of the luminol-hydrogen peroxide system by colloidal cupric oxide nanoparticles as peroxidase mimic

As a peroxidase mimic, cupric oxide nanoparticles were found to enhance the chemiluminescence (CL) of luminol-H(2)O(2) system up to 400 folds. The CL spectra and radical scavengers were conducted to investigate the possible CL enhancement mechanism. It was suggested that the enhanced CL could be attributed to the peroxidase-like activity of CuO nanoparticles, which effectively catalyzed the decomposition of hydrogen peroxide into hydroxyl radicals. The effects of the reactant concentrations and some organic compounds were also investigated. The proposed method could be used as a sensitive detection tool for hydrogen peroxide and glucose.

Short-range magnetic order and temperature-dependent properties of cupric oxide

The temperature dependence of the optical and magnetic properties of CuO were examined by means of hybrid density functional theory calculations. Our work shows that the spin exchange interactions in CuO are neither fully one-dimensional nor fully three-dimensional. The temperature dependence of the optical band gap and the (63)Cu nuclear quadrupole resonance frequency of CuO originate from the combined effect of a strong coupling between the spin order and the electronic structure and the progressive appearance of short-range order with temperature.