Non-invasive detection of glucose in human urine using a color-generating copper NanoZyme

Renal complications are long-term effect of diabetes mellitus where glucose is excreted in urine. Therefore, reliable glucose detection in urine is critical. While commercial urine strips offer a simple way to detect urine sugar, poor sensitivity and low reliability limit their use. A hybrid glucose oxidase (GOx)/horseradish peroxidase (HRP) assay remains the gold standard for pathological detection of glucose. A key restriction is poor stability of HRP and its suicidal inactivation by hydrogen peroxide, a key intermediate of the GOx-driven reaction. An alternative is to replace HRP with a robust inorganic enzyme-mimic or NanoZyme. While colloidal NanoZymes show promise in glucose sensing, they detect low concentrations of glucose, while urine has high (mM) glucose concentration. In this study, a free-standing copper NanoZyme is used for the colorimetric detection of glucose in human urine. The sensor could operate in a biologically relevant dynamic linear range of 0.5-15 mM, while showing minimal sample matrix effect such that glucose could be detected in urine without significant sample processing or dilution. This ability could be attributed to the Cu NanoZyme that for the first time showed an ability to promote the oxidation of a TMB substrate to its double oxidation diimine product rather than the charge-transfer complex product commonly observed. Additionally, the sensor could operate at a single pH without the need to use different pH conditions as used during the gold standard assay. These outcomes outline the high robustness of the NanoZyme sensing system for direct detection of glucose in human urine. Graphical abstract.

Antibacterial and cytotoxic evaluation of copper and zinc oxide nanoparticles as a potential disinfectant material of connections in implant provisional abutments: An in-vitro study

OBJECTIVE

This study evaluates the antibacterial activity against mono and multispecies bacterial models and the cytotoxic effects of zinc oxide and copper nanoparticles(ZnO-NPs/Cu-NPs) in cell cultures of human gingival fibroblasts(HGFs).

DESIGN

The antibacterial activities of ZnO-NPs and Cu-NPs against 4 bacteria species were tested according to their minimum inhibitory concentrations(MICs) and against mature multispecies anaerobic model by spectral confocal laser scanning microscopy. The viabilities and cytotoxic effects of ZnO-NPs and Cu-NPs to HGFs cell cultures were tested by MTT, LDH assays, production of ROS, and the activation of caspase-3. The results were analyzed using one-way ANOVA followed by Tukey tests, considering p < 0.05 as statistically significant.

RESULTS

For all strains, MICs of ZnO-NPs and Cu-NPs were in the range of 78.3 μg/mL-3906 μg/mL and 125 μg/mL-625 ug/mL, respectively. In a multispecies model, a significant decrease in the total biomass volume(μ3) was observed in response to exposure to 125 μg/mL of each NPs for which there was bactericidal activity. Significant differences were found between the volumes of viable and nonviable biomass exposed to nanostructures with Cu-NPs compared to ZnO-NPs. Both NPs induced mitochondrial dose-dependent cytotoxicity, ZnO-NPs increases LDH release and intracellular ROS generation. Cu-NPs at a concentration of 50 μg/mL induced production of cleaved caspase-3, activating the apoptotic pathway early and at low doses.

CONCLUSIONS

After 24 h, ZnO-NPs are biocompatible between 78-100 μg/mL and Cu-NPs below 50 μg/mL. Antibacterial activity in a monospecies model is strain dependent, and in a multispecies model was a lower doses after 10 min of exposure.

Antitumor effect of copper nanoparticles on human breast and colon malignancies

Breast and colon carcinomas are two types of common cancers which lead to cancer-related deaths. Due to their cytotoxic potential against cancer cells, recently many studies of copper nanoparticles (CuNPs) have been conducted. In the current work, we aim to evaluate the cytotoxic and apoptosis-inducing effects of CuNPs on the human breast (MCF-7) and colon (LoVo) cancer cells. CuNPs were prepared in starch-stabilizing aqueous solution by electroless deposition technique in alkaline tartrate bath using formaldehyde as the reducing agent of copper sulfate. The obtained CuNPs were characterized by SEM, TEM, and XRD to confirm the particle size, morphology, and chemical composition. Standard colorimetric MTT and LDH assays were used to estimate the cytotoxic effect of CuNPs on MCF-7 and LoVo cells. Furthermore, CuNP-treated cells undergoing apoptosis were assessed based on the expression of apoptosis-related genes using qRT-PCR. The results indicate that the mean particle size of the synthesized CuNPs was ~ 50-60 nm, and they were spherical in shape with mainly the chemical structure of the copper metallic phase. MTT assay revealed that CuNPs induced cytotoxicity in tested cells with IC₅₀ rates of 16.4 (in MCF-7) and 21.6 μg/ml (in LoVo). Moreover, qRT-PCR analysis showed that CuNPs caused a significant increment of Bax, P53, and Caspases 9, 8, and 3 genes. Overall, the anticancer potential of prepared CuNPs were reported through apoptotic induction which highlight the potential use of CuNPs as an efficient anticancer agent.

Copper nanoparticles induce the formation of fatty liver in Takifugu fasciatus triggered by the PERK-EIF2α- SREBP-1c pathway

Copper nanoparticles (CuNPs), a new pollutant in water environments, were widely used in various industrial and commercial applications. This study indicated that the presence of CuNPs exposure under environmental related concentration is an inducing factor that contributes to the fatty liver formation in Takifugu fasciatus. Furthermore, we explored the fatty liver formation mechanism. The results shown, (1) the cloned genes related to endoplasmic reticulum stress (ERS) (GRP78, IRE-1α, PERK, and ATF-6α) were highly expressed in the liver of T. fasciatus. (2) after 30-days exposure, CuNPs accumulated in the endoplasmic reticulum of liver and induced the appearance of ERS, then activated unfolded protein response (UPR) signaling pathway. Furthermore, the SREBP-1c pathway that plays a key role in lipid synthesis was activated. (3) by using 4-PBA and GSK inhibitors to respectively stimulate ERS and PKR-like ER kinase (PERK) through in vitro experiments, we confirmed that CuNPs induced the fatty liver formation in T. fasciatus triggered by the PERK-EIF2α pathway by activating the SREBP-1c pathway to promote fatty liver formation. This study provides a new perspective for identifying the pathogens of fatty liver formation, and adds to the knowledge of the ecological safety data service of CuNPs in water.

Graphene oxide decorated with cellulose and copper nanoparticle as an efficient adsorbent for the removal of malachite green

In this study, the graphene oxide surface was modified by grafting of nanocellulose and copper nanoparticles to promote the surface charge and adsorption efficiency for malachite green (MG). The structural and configurational properties of GO-CEL-Cu were verified by UV/Vis, SEM, TEM, EDX and FTIR spectroscopy and confirmed the electrostatic interaction and hydrogen bonding between GO, CEL and Cu-NPs. TEM images confirmed the deposition of Cu-NPs size between 24 and 37 nm on the GO surface. The uniform fine particles size makes strong interfacial interaction with GO sheets result in efficient load transfer from the matrix to the hybrid. The variable parameters such as adsorbent amount, MG concentration, pH, time and temperature were investigated to achieve optimum experimental condition. The experimental data was justified by Langmuir isotherm model with adsorption capacity for GO, GO-Cu, GO-CEL, GO-CEL-Cu as 127.3, 149.2, 156.8 and 207.1 mg/g, respectively. The spontaneity and endothermic nature of the process were confirmed by negative Gibbs free energy and followed the pseudo-second-order rate equation. Additionally, positive values of enthalpy and entropy suggesting endothermic process and increase randomness during process, respectively. In conclusion, nanocomposite is capable to adsorb the toxic dye due to its well economic, eco-friendly, well adsorption rate and regeneration ability.

Efficient biogenesis of Cu2O nanoparticles using extract of Camellia sinensis leaf: Evaluation of catalytic, cytotoxicity, antioxidant, and anti-human ovarian cancer properties

At the moment, metallic nanoparticles especially copper nanoparticles are administrated for the cure of different disorders, such as tumor and cancer. In recent years, many chemotherapeutic supplements have been formulated by copper nanoparticles. In the present study, copper nanoparticles were prepared and synthesized in aqueous medium using Camellia sinensis leaf extract. The as-prepared Cu₂O nanoparticles was thoroughly characterized using XRD, FT-IR, FESEM, EDX, TEM and X-ray elemental mapping techniques. The as-synthesized Cu₂O/C. sinensis NPs applied as novel nanocatalyst for the synthesis of annulated fused pyrano[2,3-d]pyrimidinones via a one-pot, three-component condensation of a barbituric acid, aromatic aldehydes, and malonitrile or ethylcyanoacetate under mild condition at 25 °C. Main properties of this facile method are the involves an easy work-up procedure, avoidance of hazardous or polluting chemicals, significant yields under mild conditions, and one-pot reaction. We assessed the anti-human ovarian cancer potentials of these nanoparticles against Caov-3, SW-626, and SK-OV-3 cell lines. For investigating the antioxidant activities of CuCl₂⋅2H₂O, C. sinensis, and copper nanoparticles, the DPPH free radical test was used. For the determining of anti-human ovarian cancer properties of CuCl₂⋅2H₂O, Camellia sinensis leaf aqueous extract, copper nanoparticles, and Carboplatin (Standard positive control), MTT assay was used on normal (HUVECs) and human ovarian cancer (Caov-3, SW-626, and SK-OV-3) cell lines. Copper nanoparticles had high cell death and anti-human ovarian cancer properties against Caov-3, SW-626, and SK-OV-3 cell lines. Among the above cell lines, the best result was gained in the cell line of SW-626. According to the above findings, it looks copper nanoparticles green-synthesized by Camellia sinensis leaf aqueous extract have the potential to be used as a chemotherapeutic material for human ovarian cancers.

Effects of copper oxide nanoparticle on gill filtration rate, respiration rate, hemocyte associated immune parameters and oxidative status of an Indian freshwater mussel

Waterbodies of India support a wide range of molluscs including Lamellidens marginalis, a pearl forming edible mussel of ecological significance. Report of copper oxide nanoparticle toxicity in Indian molluscs is limited in scientific literature. L. marginalis is a gill respiring filter feeder, which is toxicologically vulnerable to exposure of copper oxide nanoparticles liberated from electrical, textile and polymer industries. Experimental exposure of copper oxide nanoparticles for 7 days yielded a decrease in gill filtration rate, respiration rate, total count and phagocytic response of hemocytes, the chief immunoeffector cells of L. marginalis. Nanoparticle exposure resulted in decrease of phagocytic response of mussel hemocytes. Decrease in nitric oxide generation and phenoloxidase activity were recorded in L. marginalis exposed to 0.5, 1 and 5 mg copper oxide nanoparticles per litre of water for 7 and 14 days. Superoxide anion generation in hemocytes was increased under the exposure of copper oxide nanoparticles. Increase in superoxide anion and decrease in the activities of superoxide dismutase and catalase were indicative to oxidative stress in mussels. Copper oxide nanoparticle induced shift in filtration and respiration rate along with the hemocyte associated immune parameters were suggestive to an acute immunophysiological stress in L. marginalis. We estimated the functional performance of gill and physiological status of aquatic respiration in L. marginalis exposed to copper oxide nanoparticles. A parallel set of estimation of each parameter was carried out in L. marginalis exposed to identical copper sulphate concentrations to record and compare the ionic toxicity of copper in the same specimen.

Copper Nanoparticles Mitigate the Growth, Immunity, and Oxidation Resistance in Common Carp (Cyprinus carpio)

The present investigation aimed to evaluate the influence of copper nanoparticles (Cu-NPs) on the growth, immunity, and oxidation resistance of common carp (3.02 ± 0.01 g, initial mean weight ± S.E.). Five groups of fish fed diets with Cu-NPs at 0, 0.5, 1, 2, and 4 mg/kg for 8 weeks. The results suggested that Cu-NPs in diets increased the growth performance and reduced FCR with linear and quadratic model (P < 0.05). Also, common carp fed Cu-NPs showed increased carcass protein, lipid, and ash contents in a dose-dependent manner (P < 0.05). The Cu accumulation in the carcass, liver, muscle, and gills increased by Cu-NPs and showed the maximum at 4 mg Cu-NPs/kg (P < 0.05). No significant alterations were found in the blood variables due to Cu-NP supplementation except for the Hb, RBCs, total protein, albumin, and globulin levels which showed the highest level in 2 mg/kg (P < 0.05). IgM level, phagocytic, lysozyme, SOD, CAT, and GPX activities were boosted by Cu-NPs with decreased malondialdehyde (MDA) content (P < 0.05). Based on regression analysis, the requirement of dietary Cu-NPs for common carp was estimated to be 2.19 to 2.91 mg/kg diet.

Photocatalytic, antiproliferative and antimicrobial properties of copper nanoparticles synthesized using Manilkara zapota leaf extract: A photodynamic approach

Copper nanoparticles were synthesized using Manilkara zapota leaf extract. The synthesis of the nanoparticle was primarily visualized when the colour of the reaction mixture turned into reddish-brown. Biosynthesized nanoparticles were characterized by UV-vis, FT-IR, XRD, SEM and EDX. The UV spectra showed maximum absorption at 584 nm. FT-IR studies showed stretching frequency at 592.76 cm^-1, which is the fingerprint region for Cu-O bond. The crystallinity of the synthesized copper nanoparticles (Mz-Cu NPs) was revealed through XRD analysis. The synthesized Mz-Cu NPs were spherical with an average size of 18.9-42.5 nm and it was shown by SEM analysis. EDX analysis displayed that the nano sample contains 58 % of copper. The antimicrobial property of the synthesized nanoparticles was evaluated against fungal plant pathogens Rhizoctonia solani (MTCC 12232), Sclerotium oryzae (MTCC 12230) and bacterial species, namely Bacillus subtilis (ATCC 23857), Escherichia coli (ATCC 25922), Staphylococcus aureus (ATCC 25923), Vibrio harveyi (ATCC 35084), Vibrio parahaemolyticus (ATCC 33845). In in-vitro haemolytic assay, the particle showed 5.73, 3.34, 0.5 % hemolysis at 100, 50, 25 μg/mL concentration respectively. In the antiproliferative assay, the IC₅₀ values of MCF7 and Vero cells were found to be 53.89 and 883.69 μg/μl. The particle degraded Methyl violet, Malachite green and Coomassie brilliant blue by 92.2, 94.9 and 78.8 %, within 50, 40 and 60 min, respectively, through its photocatalytic activity.

Green synthesis of copper nanoparticles using Celastrus paniculatus Willd. leaf extract and their photocatalytic and antifungal properties

This research aimed to explore the eco-friendly green synthesis of copper nanoparticles (CuNPs) using Celastrus paniculatus leaves extract. Primarily, the biosynthesized CuNPs characterized by UV-vis spectroscopy showed an absorption peak at 269 nm. Further, The SEM and TEM studies revealed the spherical shape of particles with size ranged between 2-10 nm with an average particle diameter of 5 nm. FT-IR analysis confirmed the presence of functional groups -OH, C[bond, double bond]C and C-H triggers the synthesis of CuNPs. The negative zeta potential -22.2 mV indicated the stability of CuNPs was confirmed by DLS and the composition and purity by EDS studies. Further, the photocatalytic property of the CuNPs was divulged by their methylene blue dye degradation potential. The reaction kinetics followed pseudo-first-order with k-values (rate constant) 0.0172 min-1. In addition, this material was found to be a good antifungal agent against plant pathogenic fungi Fusarium oxysporum showed 76.29 ± 1.52 maximum mycelial inhibition.

Sensitive detection of microRNA using a label-free copper nanoparticle system with polymerase-based signal amplification

The abnormal expression of microRNAs (miRNAs) has been reported in many diseases, so it is of great interest to develop simple and accurate methods for the detection and analysis of miRNA expression. We have developed a novel biosensor to detect miRNAs. This method is based on a polymeric double-stranded DNA (dsDNA) copper nanoparticle (CuNP) template that is synthesised by a polymerase. When Cu²⁺ and ascorbic acid are added to the system, the dsDNA template (which is rich in A-T bases) promotes the formation of CuNPs, resulting in high fluorescence intensity. This system provides sensitive analysis of miRNA expression with a limit of detection down to 17.8 pmol/L, due to significant changes in the fluorescence signal of the system before and after the addition of the target. The linear range between F₀-F and concentration of miR-122 is 80.0 pmol/L to 4.50 nmol/L, and the recovery rate in spiked HepG2 cell lysates is 93.33-102.53%. This method expands the applications of fluorescent DNA-CuNPs in the field of biosensor analysis, and can be used to detect and analyse any miRNA marker by changing the target recognition sequence. Graphical abstract A label-free dsDNA-CuNP-based and enzyme-assisted signal amplification method for microRNA is constructed.

Green synthesis and characterization of copper nanoparticles using Piper retrofractum Vahl extract as bioreductor and capping agent

The copper nanoparticles (CuNPs) have attracted much attention due to their application in diverse fields. The applications of CuNPs depend on their physical and chemical properties. This study presents the first report for the use of medicinal fruit extract of Piper retrofractum Vahl as an eco-friendly reagent in the synthesis of CuNPs using copper sulfate as a starting material. Piper retrofractum Vahl extract was employed as a bioreductor as well as a capping agent in the formation of CuNPs. The reaction process was assisted by sonication and stirring. The influences of extract concentration, pH, temperature, and reaction time on the size of CuNPs were studied in detail. The morphology and structure of synthesized CuNPs were characterized by UV-Vis, FT-IR, SEM-EDS, TEM, and XRD. The UV-Vis measurement showed the surface plasmon resonance (SPR) peak at 234-255 nm, whereas FTIR characteristic peaks of metal-oxygen (Cu-O) were confirmed in the range 550-570 cm-1 and Cu-O-H bonds led to bending absorptions in the region 870-880 cm-1. The synthesized CuNPs possess the spherical shapes and high content of copper (70.3%) as confirmed by SEM-EDS. From the TEM micrograph, it can be seen that the particle size distribution of CuNPs has a high uniformity with a size of 2-10 nm under the optimum condition. The crystalline nature of CuNPs as confirmed by XRD showed the crystallinity phase of 26.4%. The synthesized CuNPs have relatively good stability and could inhibit Escherichia coli and Staphylococcus aureus. The results proved that Piper retrofractum Vahl fruit extract could be applied for a greener synthesis of CuNPs with high uniformity of particle sizes.

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.