Multifunctional molybdenum disulfide-copper nanocomposite that enhances the antibacterial activity, promotes rice growth and induces rice resistance

Molybdenum disulfide sheets loaded with copper nanoparticles (MoS₂-CuNPs) was prepared and its antibacterial activity against phytopathogen Xanthomonas oryzae pv. oryzae (Xoo) was investigated in vitro and in vivo for the first time. In a 2 h co-incubation, MoS₂-CuNPs exhibited 19.2 times higher antibacterial activity against Xoo cells than a commercial copper bactericide (Kocide 3000). In the detached leaf experiment, the disease severity decreased from 86.25 % to 7.5 % in the MoS₂-CuNPs treated rice leaves. The results further demonstrated that foliar application of MoS₂-CuNPs could form a protective film and increase the density of trichome on the surface of rice leaves, finally prevent the infection of Xoo cells. This was probably due to the synergistic effect of MoS₂-CuNPs. Additionally, foliar application of MoS₂-CuNPs (4-32 μg/mL) increased obviously the content of Mo and chlorophyll (up 30.85 %), and then improved the growth of rice seedlings. Furthermore, the obtained MoS₂-CuNPs could activate the activities of the antioxidant enzymes in rice, indicating higher resistance of rice under abiotic/biotic stresses. The multifunctional MoS₂-CuNPs with superior antibacterial activity provided a promising alternative to the traditional antibacterial agents and had great potential in plant protection.

Fluorescent detection of Cu (II) ions based on DNAzymatic cascaded cyclic amplification

A fluorescent biosensor based on the cascaded cyclic amplification-lighted copper nanoparticles has been developed, optimized, and validated. In the double-modular cascaded cyclic amplification, a DNAzymatic cyclic amplification unit transforms metal ion signal to specific DNA sequences, and a linear/exponential integrated amplification unit converts as-prepared DNA codes to identical thymine (T)-rich DNA templates. T-rich scaffolds can induce the generation of red fluorescent copper nanoparticles, with fluorescence emission at 625 nm upon the excitation at 340 nm, as signal vehicles for quantitative detection of metal ions. Copper ions, selected as the model target, could be detected in a wide linear range from 10 to 10⁴ nM depending on the increased fluorescent intensity, and the detection limit is 5.6 ± 0.52 nM (n = 3) within 40 min, which is 4 orders of magnitude lower than the limits set in drinking water. In the detection of Cu²⁺ in real tap and lake water, the results between inductively coupled plasma mass spectrometry (ICP-MS) and our proposed biosensor were consistent, illustrating the practicability of the fabricated method. In summary, the established fluorescent biosensor compensates the deficiency of immunoassays failing to analyze metal ions, broadens ranges of biomarkers responding to cleaved DNAzymes, provides an open platform sensing different metal ions, and meets the increasing need for the ultrasensitive detection in the field of food safety, environmental monitoring, and medical diagnosis.

Green and efficient biosynthesis of pectin-based copper nanoparticles and their antimicrobial activities

Herein, we reported a green biosynthesis method of copper nanoparticles (CuNPs) at microwave irradiation condition by using pectin as a stabilizer and ascorbic acid as a reducing agent. Under the optimum conditions, CuNPs1 and 2 were synthesized under microwave times 0 and 3 min, respectively. Transmission electron microscope and scanning electron microscope (SEM) tests showed that CuNPs1 and 2 had irregular polygon particles with average diameters of 61.9 ± 19.4 and 40.9 ± 13.6 nm, respectively. Zeta potentials of CuNPs1 and 2 were -45.2 and -48.7 mV, respectively. X-ray diffraction, Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy techniques were used to characterize the properties of CuNPs. Furthermore, inhibition zone tests showed that CuNPs2 exhibited higher antimicrobial activities against Escherichia coli, Staphylococcus aureus, and Aspergillus japonicus than CuNPs1. The antibacterial activities were also studied by the bacterial growth kinetics in broth media, and CuNPs2 exhibited lower minimum bactericidal concentrations than CuNPs1.

Growth inhibition of the microalgae Skeletonema costatum under copper nanoparticles with microplastic exposure

In order to investigate the combined toxicities of copper nanoparticles (nano-Cu) with microplastic on microalgae Skeletonema costatum, growth inhibition tests were carried out. The toxic effects of copper nanoparticles and microplastic on the microalgae under singleness and coexistence conditions were investigated. Both copper nanoparticles and microplastic inhibited the growth of S. costatum. The growth inhibition ratio (IR) increased with the increasing of particle concentrations and incubation time. The toxicity of copper nanoparticles was reduced with the addition of microplastic. The concentrations of Cu²⁺ in the medium with or without addition of microplastic were determined. It was found that adsorption of Cu²⁺ on microplastic and aggregation between copper nanoparticles and microplastic are the main reasons for attenuation of toxicity of nano-Cu with adding microplastic. The adhesion and aggregate interactions between microalgae and nanomaterial were also approved by the observations through scanning electron microscopy.

Green synthesized and characterized copper nanoparticles using various new plants extracts aggravate microbial cell membrane damage after interaction with lipopolysaccharide

In the present study, commercially available six plants leave extracts such as Eucalyptus camaldulensis, Azadirachta indica, Murraya koenigii, Avicennia marina, Rosa rubiginosa and Datura stramonium were utilized for the production of copper nanoparticles (CuNPs). The characterization of particles was performed by UV/Vis, TEM, SEM, EDX and FTIR spectroscopy. TEM images showed the creation of CuNPs having mean size ranged from 48 to 29 nm corresponding to different plant extracts. SEM analysis showed the formation of spherical form of NPs. FTIR spectroscopy verified the availability of phytochemical components as they serves the reducing, covering and stabilizing assistant of the CuNPs. Antimicrobial ability of NPs was performed against various clinical pathogenic strains by Oxford cup method. The synthesized NPs indicated potent antibacterial activity, with relatively low values of MIC between 15 and 60 μg/mL. The antibacterial effect of each CuNPs was observed in the resulting order A. indica > D. stramonium > M. koenigii > R. rubiginosa > A. marina > E. camaldulensis. After 12 h exposure with A. indica synthesized CuNPs, the SEM images of S. typhi showed destruction of cell membrane and cell lysis was clearly observed after interaction with lipopolysaccharide. In conclusion, these obtained CuNPs could be precisely applied in treatment protocols without any covering or core-shell procedures.

Biodistribution and toxicity assessment of copper nanoparticles in the rat brain

AIMS

The increase in the usage of copper nanoparticles (Cu NPs) in the industrial and medical fields has raised concerns about their possible adverse effects. The present study aims to investigate the potential adverse effects of Cu NPs on the brain of adult male Wistar rats through the estimation of some oxidative stress parameters and acetylcholinesterase (AChE) activity.

BASIC PROCEDURES

Cu NPs were prepared and characterized using different techniques: Dynamic Light Scattering, X-Ray Diffraction, Transmission and Scanning Electron Microscopy, Fourier transform Infrared Spectroscopy, in addition to Energy Dispersive X-ray Spectroscopy. Rats were divided into two groups: Cu NPs-treated group (IV injected with 15 mg/kg ˷ 13 nm Cu NPs for 2 successive days) and a control group (injected with saline). Rats of the 2 groups were decapitated simultaneously after 48 h of the last injection. The Cu content in different brain areas was analyzed using inductively coupled plasma mass spectrometry. Moreover, the effect of Cu NPs on brain edema was evaluated. The behavior of rats in an open-field was also examined 24 h post the last injection.

MAIN FINDINGS

Significant increases of Cu content in the cortex, cerebellum, striatum, thalamus and hippocampus were found. Moreover, Cu NPs lead to the induction of oxidative stress condition in the thalamus, hypothamaus and medulla. In addition, Cu NPs induced significant increases in AChE activity in the medulla, hippocampus, striatum besides midbrain. Cu NPs-injected rats showed also decreased exploratory behaviour.

PRINCIPAL CONCLUSION

The results obtained in the present study point to the importance of toxicity assessments in evaluating the efficiency of Cu NPs for the safe implementation in different applications.

Anti-bacterial and anti-biofilm properties of green synthesized copper nanoparticles from Cardiospermum halicacabum leaf extract

In the present study, a copper nanoparticle (Cu NPs) was synthesized by a green synthesis method with Cardiospermum halicacabum leaf extract. The surface area of Cu NPs was measured with dynamic light scattering (DLS). UV-Vis spectrum clearly illustrates the typical absorption peak of Cu NPs. The crystalline property of Cu NPs was confirmed from the XRD pattern. TEM analysis clearly indicates the average particle size of synthesized Cu NPs was in the range of 30-40 nm with hexagonal shape. Energy-dispersive spectroscopy confirms the major strong peaks of Cu NPs. FTIR analysis confirms the existence of various functional biomolecules over the metal nanoparticles and they are playing an important role in the formation of Cu NPs. The antibacterial and anti-biofilm analyses were carried out to confirm their aptitude for biomedical applications. Interestingly, Cu NPs control the development of biofilm by attaching over the cell wall and disturb their growth and development.

Rainbow trout (Oncorhynchus mykiss) chemosensory detection of and reactions to copper nanoparticles and copper ions

Copper is known to interfere with fish olfaction. Although the chemosensory detection and olfactory toxicity of copper ions (Cu²⁺) has been heavily studied in fish, the olfactory-driven detection of copper nanoparticles (CuNPs)-a rapidly emerging contaminant to aquatic systems-remains largely unknown. This study aimed to investigate the olfactory response of rainbow trout to equitoxic concentrations of CuNPs or Cu²⁺ using electro-olfactography (EOG, a neurophysiological technique) and olfactory-mediated behavioural assay. In the first experiment, the concentration of contaminants known to impair olfaction by 20% over 24 h (EOG-based 24-h IC20s of 220 and 3.5 μg/L for CuNPs and Cu²⁺, respectively) were tested as olfactory stimuli using both neurophysiological and behavioural assays. In the second experiment, to determine whether the presence of CuNPs or Cu²⁺ can affect the ability of fish to perceive a social cue (taurocholic acid (TCA)), fish were acutely exposed to one form of Cu-contaminants (approximately 15 min). Following exposure, olfactory sensitivity was measured by EOG and olfactory-mediated behaviour within a choice maze was recorded in the presence of TCA. Results of neurophysiological and behavioural experiments demonstrate that rainbow trout can detect and avoid the IC20 of CuNPs. The IC20 of Cu²⁺ was below the olfactory detection threshold of rainbow trout, as such, fish did not avoid Cu²⁺. The high sensitivity of behavioural endpoints revealed a lack of aversion response to TCA in CuNP-exposed fish, despite this change not being present utilizing EOG. The reduced response to TCA during the brief exposure to CuNPs may be a result of either olfactory fatigue or blockage of olfactory sensory neurons (OSNs) by CuNPs. The observed behavioural interference caused by CuNP exposure may indicate that CuNPs have the ability to interfere with other behaviours potentially affecting fitness and survival. Our findings also revealed the differential response of OSNs to CuNPs and Cu²⁺.

Effect of morphology and support of copper nanoparticles on basic ovarian granulosa cell functions

The aim of this survey is to explore the possible effects of unsupported and supported copper nanoparticles (CuNPs) of different morphologies on basic ovarian cell functions. For this purpose, we have compared the activity of unsupported spherical, triangular, and hexagonal CuNPs, as well as of spherical CuNPs supported on titania, zeolite Y and activated charcoal (0, 1, 10, or 100 ng/mL) on cultured porcine ovarian granulosa cells. Cell viability, proliferation (accumulation of proliferating cell nuclear antigen, PCNA), apoptosis (accumulation of Bcl-2-associated X protein, bax) and release of steroid hormones progesterone, testosterone, and 17β-estradiol have been analyzed by the Trypan blue test, quantitative immunocytochemistry, and ELISA, respectively. Cell viability decreased after treatment with hexagonal CuNPs, whilst all the other CuNPs increased it. Unsupported spherical and hexagonal CuNPs, and spherical CuNPs/titania reduced PCNA accumulation; in contrast, an increase was noted for unsupported triangular CuNPs and CuNPs/zeolite Y. Bax accumulation was not affected by hexagonal CuNPs, whereas CuNPs/zeolite Y promoted it and all the other CuNPs depleted it. The release of all steroid hormones was inhibited by CuNPs/titanium dioxide and stimulated by CuNPs/charcoal, whilst CuNPs/zeolite Y promoted the testosterone and 17β-estradiol output, but not that of progesterone. These results demonstrate the direct, mainly stimulatory, impact of CuNPs on basic ovarian cell functions. The character of the CuNPs' action depends on their shape and support. Therefore, CuNPs with appropriate chemical modification could be potentially useful for the control of reproductive processes and treatment of reproductive disorders.

Use of biogenic copper nanoparticles synthesized from a native Escherichia sp. as photocatalysts for azo dye degradation and treatment of textile effluents

Textile wastewater contains a huge amount of azo dyes and heavy metals and catastrophically deteriorates the agricultural field by affecting its phyisco-chemical/biological and nutritional properties when directly drained to agricultural lands without any treatment. Recently, biogenic copper nanoparticles (CuNPs) have gained considerable attention for photocatalytic degradation of wastewater pollutants owing to their unique physico-chemical and biological properties, low cost and environmental sustainability. The current study reports the synthesis of CuNPs by a native copper-resistant bacterial strain Escherichia sp. SINT7 and evaluation of the photocatalytic activity of the biogenic CuNPs for azo dye degradation and treatment of textile effluents. Scanning electron microscopy and transmission electron microscopy revealed the spherical shape of biogenic CuNPs with particle size ranging from 22.33 to 39 nm. Moreover, X-ray diffraction data revealed that the CuNPs have spherical crystalline shapes with an average particle size of 28.55 nm. FTIR spectra showed the presence of coating proteins involved in the stabilization of nanomaterial. Azo dye degradation assays indicated that CuNPs decolorized congo red (97.07%), malachite green (90.55%), direct blue-1 (88.42%) and reactive black-5 (83.61%) at a dye concentration of 25 mg L^-1 after 5 h of sunlight exposure. However, at 100 mg L^-1 dye concentration, the degradation percentage was found to be 83.90%, 31.08%, 62.32% and 76.84% for congo red, malachite green, direct blue-1 and reactive black-5, respectively. Treatment of textile effluents with CuNPs resulted in a significant reduction in pH, electrical conductivity, turbidity, total suspended solids, total dissolved solids, hardness, chlorides and sulfates as compared to the non-treated samples. Thus, the promising dye detoxification and textile effluent recycling efficiency of biogenic CuNPs may lead to the development of eco-friendly and cost-efficient process for large-scale wastewater treatment.

Green synthesis of copper & copper oxide nanoparticles using the extract of seedless dates

In the last few years, copper and copper oxide nanoparticles were involved in many applications; this encouraged many researchers worldwide to develop more facile synthesis methods. Unprecedentedly, the current study reports a green method for synthesizing copper/copper oxide nanoparticles (Cu/Cu₂O NPs) using the extract of seedless dates. Cu/Cu₂O NPs were synthesized according to the chemical reduction method using seedless dates' extract as a reducing agent due to its high content of phenolics and flavonoids. Transmission Electron Microscopy (TEM) revealed that roughly spherical particles were synthesized. Dynamic Light Scattering (DLS) showed that the synthesized Cu/Cu₂O NPs have an average particle size of 78 nm and zeta potential of +41 mV, indicating a good stability of the particles. Successful synthesis of Cu/Cu₂O NPs was affirmed through both X-Ray Diffraction (XRD), which revealed the presence of the characteristic peaks of copper at 2θ = 43.2745, 50.4083 and 74.1706°, and UV-Vis. Spectroscopy, which revealed the surface plasmonic resonance peak characterizes Cu/Cu₂O NPs at 576 nm. In addition, Fourier Transform Infrared Spectroscopy (FTIR) revealed the presence of phenolic compounds, which were responsible for reducing copper ions into copper nanoparticles through their carbonyl and hydroxyl linkages, adsorbed from the extract on Cu/Cu₂O NPs. Conclusively, the current work provides, for the first time, a simple, cost-effective and environmentally friendly method for synthesizing Cu/Cu₂O NPs using useless seedless dates.

Synthesis of fluorescent pink emitting copper nanoparticles and sensitive detection of α-naphthaleneacetic acid

Detecting NAA in food has drawn intense attention as it has imposed significant threat to people's health and the growth of food industry. Over the past few years, great importance has been attached to the application of copper nanomaterials as fluorescent probe to food and environmental detection. Here, the simple, rapid, cost effective and water soluble fluorescent copper nanoparticles were synthesized with chemical reduction sonochemical assisted method for highly selective and sensitive detection of α-naphthaleneacetic acid (NAA) by using 2-mercaptobenzothiazole (MBT) as a protecting agent and polyvinylpyrrolidone (PVP) as a stabilizing agent (MBT-PVP CuNPs). The resultant CuNPs has a spherical shape with an average diameter of 10-15 nm and strong fluorescent pink emission characteristic peak at 580 nm upon 334 nm excitation. Interestingly, upon the addition of NAA, the fluorescence of MBT-PVP CuNPs can be effectively quenched for the reason that NAA could interact with MBT via hydrogen bonding and conform copper-NAA clathrate with Cu⁺ via coordination bond, which shows a good linearity in the range of NAA from 0.5 to 50 μM and with a detection limit of 9.6 nM. Moreover, the prepared probe has good selectivity for NAA detection over other co-existing molecules. It is worth mentioning that this method has been successfully applied to authentic comestible sample analysis and obtained satisfying and promising results, which indicates that this strategy is likely to have a promising application potential for NAA detection in the field of food safety.

Phytic acid doped poly(3,4-ethylenedioxythiophene) modified with copper nanoparticles for enzymeless amperometric sensing of glucose

A nanocomposite consisting of phytic acid (PA) that was doped with poly(3,4-ethylenedioxy-thiophene) (PEDOT) and modified with copper nanoparticles (CuNPs) was placed on a glassy carbon electrode and then applied in an enzymeless glucose sensor. The undulating PEDOT/PA composite has good conductivity and a large surface area, which was suitable as substrate for the uniform growth of CuNPs. The modified electrode typically operated at a potential near 0.55 V (vs. Ag/AgCl) demonstrated remarkable catalytic activity towards direct oxidation of glucose in NaOH solution (the major limitation of this sensor). Figures of merit include (a) a wide analytical range (5 to 403 μM); (b) high sensitivity (79.27 μA·μM^-1·cm^-2), (c) a low detection limit (0.28 μM at a signal to noise ratio of 3), and (d) fast response (< 4 s). Graphical abstractA nanocomposite of phytic acid (PA) doped poly(3,4-ethylenedioxy-thiophene) (PEDOT) modified with copper nanoparticles (CuNPs) onto a glassy carbon electrode was prepared by electrochemical strategy. The CuNPs/PEDOT/PA-modified electrodes were applied in enzymeless glucose sensors with high performance.

Aqueous-phase synthesis of nanoparticles of copper/copper oxides and their antifungal effect against Fusarium oxysporum

Different copper based-materials have been used for controlling some fungal and bacterial pathogens. However, the antifungal activity of the copper-based materials depends on different parameters, such as the crystal phase, synthesis route, and size of the particles. Herein a facile route synthesis method of Cu/Cu_xO-NPs was achieved through the aqueous phase. The influence of NaBH₄ concentration on the phase composition was studied. The synthesized Cu/Cu_xO-NPs were characterized by X-Ray diffraction (XRD), Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and dynamic light scattering. Five Cu/Cu_xO-NPs with different phase composition and nanoparticle size were obtained. The antifungal activity of the synthesized Cu/Cu_xO-NPs was studied in vitro against Fusarium oxysporum. The results indicate that a high percent of inhibition of radial growth (IGR) was obtained with NPs, which have a higher proportion of Cu₂O phase and relatively smaller size particles. Furthermore, hypha morphology, membrane damage and production of reactive oxygen species (ROS) was evaluated with SEM and confocal microscopy.

A cost effective strategy for dual channel optical sensing of adrenaline based on 'in situ' formation of copper nanoparticles

Assessment of adrenaline (ADR) levels in biological fluids and pharmaceutical formulations is of prime importance due to its association with many disease conditions. Here a novel, cost effective, dual channel sensing strategy is developed for ADR based on in situ formation of copper nanoparticles. The proposed sensor works via both fluorimetry and colorimetry. Visual detection was also enabled by color change of solution from pale blue to reddish brown. Here CuCl₂ solution is used as probe to simplify method and was function as excellent fluorimetric as well as colorimetric ADR sensor. Fabricated sensor is very simple, selective and reproducible in nature. Proposed sensor works fluorimetrically in linear range of 3.00 × 10^-5 to 5.00 × 10^-7 M and colorimetrically in linear range of 5.00 × 10^-4 to 2.00 × 10^-5 M. Artificial urine and commercial pharmaceutical formulations were successfully analyzed as samples for estimation of ADR by developed dual channel sensor.

18-month clinical evaluation of a copper-containing universal adhesive in non-carious cervical lesions: A double-blind, randomized controlled trial

OBJECTIVE

This study aimed to evaluate the addition of copper nanoparticles (CuNp) on the clinical performance of a universal adhesive system used as etch-and-rinse (ER) and self-etch (SE).

METHODS

216 restorations were randomly placed in 36 subjects according to the following groups: ERcu = etch-and-rinse with 0.1% CuNp; ERct = etch-and-rinse without CuNp; SEcu = self-etch with 0.1% CuNp; SEct = self-etch without CuNp. Resin composite was placed incrementally and light-cured. The restorations were evaluated at baseline and 6, 12 and 18 months using the FDI and USPHS criteria. Statistical analyses were performed using appropriate tests (α = 0.05).

RESULTS

The addition of CuNp did not increase the clinical performance (FDI / USPHS) of the universal adhesive tested after 18-month when applied in the ER mode (p > 0.05). The addition of CuNp in SE restorations increased the retention rate significantly and decreased the marginal discrepancies after 18 months (p < 0.05).

CONCLUSION

The clinical performance of universal adhesive was significantly increased when applied in the SE mode with the addition of copper nanoparticles.

CLINICAL RELEVANCE

This is the first study that demonstrates a slight improvement in the clinical performance of universal adhesive systems in non-carious cervical lesions when added CuNp in lower concentration.

The potential exposure and hazards of copper nanoparticles: A review

Copper is an essential element for metabolism in plants and animals. In its nanoform, copper has found various applications, thus increasing potential environmental exposure. Released nanoparticles in the environment undergo various transformation processes while bioaccumulation and toxicity of copper nanoparticles have been demonstrated in plants and animals. This toxicity is thought to be a combined effect of intracellular particles and the release of dissolved copper ions. Oxidative stress responses have been studied in copper nanoparticle induced effects as well as other pathways to cytotoxicity. The antimicrobial potential of copper nanoparticles makes them excellent components for application in biomedicine and more recently, they have been investigated for applications as drug delivery agents in cancer therapy. These properties of copper nanoparticles necessitate a thorough review and understanding of toxic mechanisms of action and the associated implications of exposure to human and environmental health.

The interaction between resveratrol and two forms of copper as carbonate and nanoparticles on antioxidant mechanisms and vascular function in Wistar rats

BACKGROUND

Experimental studies have emphasized that cardiovascular alterations can be improved by the long-term use of resveratrol (trans-3,5,4'-trihydroxystilbene; RSV) as well as dietary copper (Cu) intake.

METHODS

Male Wistar rats were supplemented for 8 weeks with Cu (6.5 mg/kg diet) as either nanoparticles (40 nm, CuNPs) or carbonate (CuCO3). Half of the studied animals were supplemented with RSV (500 mg/kg diet). Vascular function and blood plasma antioxidant status, expressed as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), lipid hydroperoxides (LOOH) and malondialdehyde (MDA) were analyzed. The activity of ceruloplasmin (Cp), lipid profile, fasting glucose, and concentrations of Cu and zinc (Zn) were analyzed.

RESULTS

RSV supplementation resulted in the elevated activity of SOD and decreased CAT, GPx and LDL-cholesterol in both groups. RSV supplementation on CuNPs increased the participation of vasoconstrictor prostanoids and decreased ACh-induced vasodilation, while the participation of hyperpolarizing mechanism(s) was restored by activating KATP channels. Blood plasma glucose was decreased. RSV supplementation on CuCO3 enhanced ACh- and SNP-induced vasodilation and decreased NA-induced vasoconstriction. The lipid profile was improved, as well as Zn concentration. Meanwhile, Cu and Cp, and the markers of lipid peroxidation, reflected as LOOH and MDA, were decreased.

CONCLUSION

The use of RSV during CuCO3 intake improves vascular responses, the lipid profile and the antioxidant mechanism(s). The beneficial role of RSV was not observed in the CuNP group and decreased ACh-induced vasodilation and increased participation of vasoconstrictor prostanoids in the vascular regulation were noticed.

Screen printed carbon electrode modified with a copper@porous silicon nanocomposite for voltammetric sensing of clonazepam

The work describes an electrochemical sensor for the determination of the tranquilizer clonazepam (CZP) in serum and pharmaceutical preparations. A screen printed carbon electrode (SPCE) was modified with copper nanoparticles anchored on porous silicon (PSi). The surface of the SPCEs modified with the Cu/PSi nanostructure was characterized by X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoemission spectroscopy, energy dispersive X-ray spectroscopy and field-emission scanning electron microscopy. Cyclic and differential pulse voltammetric methods were used for the electrochemical studies and electrochemical detection, respectively. Several parameters controlling the performance of the modified SPCE were optimized. The peak current values (at a potential of -0.52 V) were used to construct calibration plots. Under the optimum conditions, the calibration plot is linear in the 0.05-7.6 μM CZP concentration range, and the detection limit is 15 nM. The sensor is reproducible, repeatable, highly selective and sensitive. It was successfully applied to the determination of CPZ in spiked serum and in drugs. Graphical abstract Scheme of electrochemical reduction of clonazepam on the designed copper@porous silicon modified screen printed carbon electrode (CuNPs/PSi/SPCE). This electrode was employed for the determination of clonazepam in tablets and human blood plasma using differential pulse voltammetry.

Green-synthesized copper nano-adsorbent for the removal of pharmaceutical pollutants from real wastewater samples

The release of Non-Steroidal Anti-Inflammatory drugs (NSAIDs) such as Ibuprofen (Ibu), Naproxen (Nab) and Diclofenac (Dic) to the aquatic system cause serious environmental problems. In this study, green-synthesized copper nanoparticles (Cu NPs) have been used as nano-adsorbent for the removal of Ibu, Nab, and Dic from wastewater samples. Formation of Cu NPs was confirmed by different analytical techniques. The adsorption parameters such as temperature, pH, adsorbate concentration, adsorbent dose and contact time were studied. The best removal results were obtained at these conditions: temperature 298 K, pH = 4.5, 10.0 mg Cu NPs, 60 min. At these conditions, the removal percentage of Ibu, Nap, and Dic were found to be 74.4, 86.9 and 91.4% respectively. The maximum monolayer adsorption capacities were calculated as 36.0, 33.9 and 33.9 mg/g for Dic, Nap, and Ibu respectively. The kinetic studies conducted that the sorption process obeyed the second order kinetic model, while the thermodynamic results revealed that the adsorption process was spontaneous, endothermic (+23.8, +40.8 and +38.3 kJ/mol for Ibu, Nap and Dic respectively). The results revealed that green-synthesized copper nano-adsorbent may be used for the removal of the anti-inflammatory drugs from real wastewater efficiently.

Gene expression is influenced due to 'nano' and 'ionic' copper in pre-formed Pseudomonas aeruginosa biofilms

Today, researchers across the globe suggest the use of antimicrobial coatings containing copper nanoparticles (CuNPs) complementing the traditional protocols to prevent hospital-acquired infections (HAIs). Since Pseudomonas aeruginosa is one of the commonest opportunistic pathogens, we assessed the anti-biofilm activity of CuNPs in P. aeruginosa MTCC 3541 and compared it with Cu²⁺ (copper sulphate) since the latter continues to be used as an antimicrobial-of-choice in food industries, agriculture and water treatment. In this study, we synthesized and characterized stable poly-acrylic acid (PAA) coated CuNPs with a size of 66-150 nm and zeta potential -13 mV. Pseudomonas aeruginosa MTCC 3541 biofilms were highly resistant to both CuNPs and Cu²⁺ (minimum biofilm inhibitory concentration, MBIC 300 and >600 μg/mL respectively). Scanning electron microscopy revealed alterations in cell morphology upon treatment with CuNPs. A closer analysis of the biofilm-specific gene expression (qRT-PCR) revealed that CuNPs downregulated the genes involved in biofilm matrix formation, motility, efflux, membrane lipoprotein synthesis and DNA replication. Both, CuNPs and Cu²⁺ up regulated copper resistance and biofilm dispersion genes. Copper did not affect the bacterial communication system as evidenced by downregulation of the negative regulator of quorum sensing. The gene expression analysis reveals multiple cellular targets for CuNPs and ionic Cu. The present study highlights the fact that CuNPs affect the membrane functions adversely damaging the cell surface. In pre-formed biofilms, CuNPs were more toxic and displayed distinct responses attributable due to 'nano' and 'ionic' copper. Our findings thus support the use of CuNPs for curbing HAIs.

Novel synthesis of Falcaria vulgaris leaf extract conjugated copper nanoparticles with potent cytotoxicity, antioxidant, antifungal, antibacterial, and cutaneous wound healing activities under in vitro and in vivo condition

Facile green synthesis of copper nanoparticles from different biological procedures has been indicated, but among all, biosynthesis of copper nanoparticles from medicinal plants is considered as the most suitable method. The use of medicinal plant material increases the therapeutical effects of copper nanoparticles. The aim of this study was green synthesis of copper nanoparticles from aqueous extract of Falcaria vulgaris leaf (CuNPs) and assessment of their cytotoxicity, antioxidant, antifungal, antibacterial, and cutaneous wound healing properties. These nanoparticles were characterized by X-ray diffraction (XRD), fourier-transform infrared spectroscopy (FT-IR), ultraviolet-visible spectroscopy (UV), transmission electron microscopy (TEM), and field emission scanning electron microscopy (FE-SEM) analysis. The synthesized CuNPs had great cell viability dose-dependently (Investigating the effect of the CuNPs on human umbilical vein endothelial cell (HUVEC) line) and indicated this method was nontoxic. Also, 2,2-diphenyl-1-picrylhydrazyl (DPPH) test was done to assess the antioxidant activities, which indicated similar antioxidant potentials for CuNPs and butylated hydroxytoluene. In part of cutaneous wound healing property of CuNPs, after creating the cutaneous wound, the rats were randomly divided into six groups: treatment with 0.2% CuNPs ointment, treatment with 0.2% CuSO₄ ointment, treatment with 0.2% F. vulgaris ointment, treatment with 3% tetracycline ointment, treatment with Eucerin basal ointment, and untreated control. These groups were treated for 10 days. Treatment with CuNPs ointment remarkably increased (p ≤ .01) the wound contracture, vessel, hexosamine, hydroxyl proline, hexuronic acid, fibrocyte, and fibrocytes/fibroblast rate and substantially reduced (p ≤ .01) the wound area, total cells, neutrophil, and lymphocyte compared to other groups. In antibacterial and antifungal parts of this research, the concentration of CuNPs with minimum dilution and no turbidity was considered minimum inhibitory concentration (MIC). To determine minimum fungicidal concentration (MFC) and minimum bactericidal concentration (MBC), 60 μL MIC and three preceding chambers were cultured on Sabouraud Dextrose Agar and Muller Hinton Agar, respectively. The minimum concentration with no fungal and bacterial growth were considered MFC and MBC, respectively. CuNPs inhibited the growth of all fungi at 2-4 mg/mL concentrations and removed them at 4-8 mg/mL concentrations (p ≤ .01). In case of antibacterial effects of CuNPs, they inhibited the growth of all bacteria at 2-8 mg/mL concentrations and removed them at 4-16 mg/mL concentrations (p ≤ .01). The results of XRD, FT-IR, UV, TEM, and FE-SEM confirm that the aqueous extract of F. vulgaris leaf can be used to yield copper nanoparticles with notable amount of antioxidant, antifungal, antibacterial, and cutaneous wound healing potentials without any cytotoxicity. Further clinical trials are necessary for confirmation these therapeutical effects of CuNPs in human.

Dissolution and aggregation kinetics of zero valent copper nanoparticles in (simulated) natural surface waters: Simultaneous effects of pH, NOM and ionic strength

The combined effects of pH, dissolved organic carbon (DOC) and Ca²⁺/Mg²⁺ on the dissolution and aggregation kinetics of zero valent copper engineered nanoparticles (Cu⁰ ENPs) were investigated. The dissolution and aggregation of the particles were studied in (a) synthetic aqueous media, similar in chemistry to natural surface waters, and (b) natural surface waters samples, for up to 32 or 24 h. The DOC stabilized the particles and prevented aggregation, and thus increased the available surface area. The higher available surface area in turn accelerated the dissolution of the particles. The presence of Ca²⁺/Mg²⁺, however, changed the aggregation and the dissolution of the DOC-stabilized particles. The influence of Ca²⁺/Mg²⁺ on DOC-stabilized particles was different at different pH's. In the absence of DOC, 10 mM of Ca²⁺/Mg²⁺ induced charge reversal on the particles and caused particle stability against aggregation. This subsequently increased particles dissolution. The results obtained with regard to dissolution and aggregation of the particles in natural surface waters were compared with those determined for the synthetic waters. This comparison showed that the behavior of the particles in the natural surface waters was mostly similar to the behavior determined for media at pH 9. Overall, the current study provides some novel insights into the simultaneous effects of physicochemical parameters of water on particle stability against aggregation and dissolution, and provides data about how the processes of aggregation and dissolution of Cu⁰ ENPs interact and jointly determine the overall particle fate.

Ultrasonic preparation, stability and thermal conductivity of a capped copper-methanol nanofluid

This paper describes a two-step method to prepare novel copper-methanol nanofluids capped with a short chain molecule, (3-Aminopropyl)trimethoxysilane (APTMS). Two commercial nanopowders were dispersed at various powers using a 20 kHz ultrasonic probe into solutions of methanol and the capping agent. Ultrasonic energy input was measured by calorimetry with z-average diameters, intensity and number size distributions recorded by a dynamic light scattering technique. The stability of the dispersion was monitored visually, and quantified by recording the zeta potential. Dispersions of the bare powder were used as a control. Absorption spectroscopy was used to confirm the presence of the capping agent. The thermal conductivities of 0 to 10% wt./vol. (1.1% vol.) dispersions of the capped copper-methanol nanofluid were determined using a C-Therm analyzer. Optimum ultrasonic de-agglomeration conditions gave dispersions with a z-average particle size of <200 nm and a PdI of <0.2. The capped particles showed good stability; up to six months in some instances, and an average zeta potential of +38 mV was recorded. The thermal conductivity of the nanofluid increased with concentration, and an enhancement of 9% over the base fluid was found at 10% wt./vol. (1.1% vol.). This innovative work has demonstrated the ultrasonic preparation and stability of copper nanoparticles protected with APTMS; a short chain molecule which binds to copper and prevents oxidation. The protected particles can enhance the thermal conductivity of methanol with no interference from the capping ligand.

Short term changes in the abundance of nitrifying microorganisms in a soil-plant system simultaneously exposed to copper nanoparticles and atrazine

Copper nanoparticles (NCu) may co-exist with other pollutants in agricultural soils, such as pesticides. However, this has been little evaluated yet. Thus, possible effects of the simultaneous applications of pesticides and NCu on biogeochemical cycles are expected, for example on the nitrogen cycle. Therefore, the aim of this work was to evaluate the effect of simultaneous application of the herbicide atrazine (ATZ) and NCu on the abundance of total bacteria and nitrifying communities: ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB). Moreover, the ATZ dissipation was evaluated. A soil-plant system containing ATZ at field dose (3 mg a.i. kg^-1) was mixed with two doses of NCu (0.05% or 0.15% w/w). Changes in the abundance of 16S rRNA and ammonia monooxygenase (amoA) genes of AOA and AOB were evaluated by real-time quantitative PCR (qPCR) at three sampling times (1, 15 and 30 days). The residual ATZ and nitrate production were also measured. The results showed significant differences in microbial composition and abundance over the 30 days of the experiment. Particularly, an initial decrease was observed in total bacterial abundance due to the presence of ATZ and NCu respect to ATZ alone (~60%). The abundance of AOA was also remarkably reduced (~85%), but these communities gradually recovered towards the end of the experiment. Conversely, AOB abundance initially increased (>100%) and remained mainly unaltered in soil exposed to ATZ and NCu 0.15% w/w, where nitrate formation was also constant. Moreover, NCu decreased the ATZ dissipation, which was translated in a 2-fold increase on the ATZ half-life values (T_1/2). This study demonstrates that the simultaneous presence of NCu and ATZ may represent a risk for the total bacteria present in soil and sensitive microorganisms such as nitrifying communities, and changes in the dissipation of the pesticide could influence this process.