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This study presents a novel approach for the rapid and reliable electrochemical determination of 5-hydroxymethylfurfural (5-HMF) in honey using a screen-printed carbon electrode modified with nickel oxide nanoparticles (NiONPs/SPCE). The NiONPs were synthesized using a simple method and characterized using scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The NiONPs/SPCE demonstrated enhanced sensitivity and selectivity for 5-HMF detection. The electrochemical behavior of 5-HMF on the NiONPs/SPCE was investigated using techniques such as cyclic voltammetry (CV) and square wave voltammetry (SWV). The optimum experimental conditions were obtained including a 5 μL of 5.0 mg/mL NiONPs modifier, the voltammetric response of step potential 15 mV, amplitude 50 mV and frequency 50 Hz in 0.1 M BR buffer pH 13 as supporting electrolyte. The proposed method exhibited a linear relationship between the cathodic peak current and the concentration of 5-HMF in the concentration ranges of 0.5–5.0 ppm, with a limit of detection (LOD) of 0.24 ppm. The selectivity of the NiONPs/SPCE was evaluated by studying potential interferences commonly found in honey samples, and the results demonstrated excellent selectivity for 5-HMF detection. The reproducibility and stability of the NiONPs/SPCE were also assessed, with low relative standard deviations (RSD) obtained for both the cathodic peak current (2.94 %) and long-term stability (3.14 %). The developed NiONPs/SPCE method was successfully applied to the determination of 5-HMF in real honey samples, yielding comparable results to the standard HPLC method. This work showcases the potential of the NiONPs/SPCE as a practical and cost-effective electrochemical sensor for the accurate analysis of 5-HMF in honey samples. [Display omitted] • NiONPs modified SPCE was constructed as a facile and disposable electrochemical sensor for 5-HMF detection. • NiONPs was utilized to improve the electrochemical performance of 5-HMF reduction. • It exhibits a high sensitivity, low LOD, a good selectivity and reproducibility. • The propose method can be employed to determine 5-HMF in real honey samples. [ABSTRACT FROM AUTHOR]

Nickel oxide nanoparticles (NiONPs) are toxic heavy metal compounds that induce liver fibrosis and metabolic disorders. Current research shows that the intestinal microbiota regulates liver metabolism through the gut-liver axis. However, it is unclear whether NiONPs affect the intestinal microbiota and the relationship between microbiota and liver metabolic disorders. Therefore, in this study, we established liver fibrosis model by administering 0.015, 0.06 and 0.24 mg/mL NiONPs through tracheal instillation twice a week for 9 weeks in rats, then we collected serum and fecal sample for whole metabolomics and metagenomic sequencing. As the result of sequencing, we screened out seven metabolites (beta-D-glucuronide, methylmalonic acid, linoleic acid, phosphotidylcholine, lysophosphatidylinositol, docosapentaenoic acid and progesterone) that related to functional alterations (p < 0.05), and obtained a decrease of probiotics abundances (p < 0.05) as well as a variation of the microbiota enzyme activity (p < 0.05), indicating that NiONPs inhibited the proliferation of probiotics. As the result of correlation analysis, we found a positive correlation between differential metabolites and probiotics, such as lysophosphatidylinositol was positively correlated with Desulfuribacillus, Jeotgallibacillus and Rummeliibacillus (p < 0.05). We also found that differential metabolites had correlations with differential proteins and enzymes of intestinal microbiota, such as glucarate dehydratase, dihydroorotate dehydrogenase and acetyl-CoA carboxylase (p < 0.05). Finally, we screened six metabolic pathways with both differential intestinal microbiota enzymes and metabolites were involved, such as pentose and glucuronate interconversions, and linoleic acid metabolism. In vitro experiments showed that NiONPs increased the transcriptional expression of Col1A1 in LX-2 cells, while reducing the mRNA expression of serine/threonine activators, acetyl coenzyme carboxylase, and lysophosphatidylinositol synthase, and short chain fatty acid sodium butyrate can alleviate these variation trends. The results proved that the intestinal microbiota enzyme systems were associated with serum metabolites, suggesting that the disturbance of intestinal microbiota and reduction of probiotics promoted the occurrence and development of NiONPs-induced liver fibrosis by affecting metabolic pathways. [Display omitted] • NiONPs induced the changes of intestinal microbiota and serum metabolites. • The reduction of intestinal probiotics was correlated to serum metabolic disorders. • Intestinal microbiota enzymes participated in metabolic pathways of differential metabolites. [ABSTRACT FROM AUTHOR]

[Display omitted] • NiO-nanoparticles/GrE electrode was prepared and used as electrochemical sensor. • The heavy metal Cu(II) was detected at trace levels using SWASV technique. • The sensor was validated for copper determination in real environmental samples. • Low LOD and LOQ, and high sensitivity were obtained under the optimal conditions. • High selectivity, simple on-site operation, quick and affordable analysis. Nickel oxide film (NiO-nanoparticles) was successfully deposed onto the carbon graphite electrode (GrE) and used as an electrochemical sensor for the detection of trace levels of copper Cu(II) by using square wave anodic stripping voltammetry (SWASV). This cost-effective and simple sensor was developed through a two-step process. In the initial step, the electrochemical deposition of metallic nickel onto the carbon graphite electrode occurs in a 0.1 M boric acid and nickel salt solution. Subsequently, in the second step, the deposited metal undergoes anodic oxidation in a 0.1 M NaOH solution. To characterize and verify the modification process of the electrode, several electrochemical and physico-chemical techniques were employed such as OCP, EIS, SEM, XRD and XPS. In an acid medium, the modified electrode exhibited a significant improvement in electrocatalytic activity for the oxidation of Cu(II) compared to bare GrE. The effect of several parameters on the sensor response were also examined. Under optimal conditions, the sensor exhibited a linear response to Cu(II) concentrations ranging from 0.0 to 1.5 × 10−7 M with a detection limit of 3.83 × 10−9 M, quantification limit of 1.37 × 10−8 M and a high sensitivity of 226.13 μA.M−1.cm−2. Furthermore, the sensor showed a good repeatability (RSD = 1.47 %), a good stability (retain 99.5 % after 40 measurements) and a minimal interference from ionic species was observed on the SWASV signals of Cu(II). The as-prepared sensor was then applied to determine the Cu(II) in two different brands of local source water, and the results were very satisfactory by showing a recovery values between 97.5 and 103.6 %. In summary, our study presents an innovative and cost-effective electrochemical sensor utilizing a modified carbon graphite electrode for sensitive and accurate detection of copper at trace levels. [ABSTRACT FROM AUTHOR]

The exceptional physical and chemical properties of nickel nanomaterials have been exploited in a range of applications such as electrical conductors, batteries, and biomaterials. However, it has been suggested that these unique properties may allow for increased bioavailability, bio-reactivity, and potential adverse health effects. Thus, the purpose of this review was to critically evaluate data regarding the toxicity of oxidic nickel nanoparticles (nickel oxide (NiO) and nickel hydroxide (Ni(OH)2) nanoparticles) with respect to: (1) physico-chemistry properties; (2) nanomaterial characterization in the defined delivery media; (3) appropriateness of model system and translation to potential human effects; (4) biodistribution, retention, and clearance; (5) routes and relevance of exposure; and (6) current research data gaps and likely directions of future research. Inhalation studies were prioritized for review as this represents a potential exposure route in humans. Oxidic nickel particle size ranged from 5 to 100 nm in the 60 studies that were identified. Inflammatory responses induced by exposure of oxidic nickel nanoparticles via inhalation in rodent studies was characterized as acute in nature and only displayed chronic effects after relatively large (high concentration and long duration) exposures. Furthermore, there is no evidence, thus far, to suggest that the effects induced by oxidic nickel nanoparticles are related to preneoplastic events. There are some data to suggest that nano- and micron-sized NiO particles follow a similar dose response when normalized to surface area. However, future experiments need to be conducted to better characterize the exposure–dose–response relationship according to specific surface area and reactivity as a dose metric, which drives particle dissolution and potential biological responses.

In the present stud, NiO–NPs have been synthesized via the sol–gel method and using okra plant extract as a reducing and limiting agent. The optical, photocatalytic, structural and magnetic properties of the NiO–NPs have been investigated via the usage of FTIR, UV–Vis, XRD, FESEM, EDX, VSM, and TGA/DTA. The results of the achieved XRD and FT-IR analyses have confirmed the formation of pure and crystalline NiO–NPs. The thermal behavior of the composition has been studied by the utilization of TGA/DTA results. Moreover, the synthesized NiO–NPs have illustrated a super-paramagnetic behavior throughout the performance of magnetic studies by the means of VSM procedure. Cell cytotoxicity investigation has been carried put on multiple tumor cells by the MTT method, while the antimicrobial studies have displayed that NiO–NPs activity for gram-positive bacteria species seems to be more apparent than the gram-negative bacteria species. Photocatalytic degradation researches have confirmed the consistency of its effects with complete degradation of MB in pH = 11, under optimal conditions. Therefore, we propose a green protocol for the combination of effective biological agents with high purity and crystallinity along with reduced particle size, which stands as beneficial factors to be employed in a variety of applications and environments. [ABSTRACT FROM AUTHOR]

Nickel oxide nanoparticles (NiO NPs) were synthesized through template free sol–gel method. Synthesized particles were calcined at 300∘C, 500∘C and 700∘C for 2 h and further the particles were characterized for its thermal, functional, structural, morphological and optical properties. The peak broadening analysis was undertaken in order to calculate the variation in size and strain components of the particles with the calcinations temperature. The Debye–Scherer, Williamson–Hall and Size-strain plot methods were employed in peak broadening analysis and were compared with TEM results. All the NiO NPs crystallite size and lattice strain value were found to be in good agreement with all the models. The TEM analysis revealed that the calcinations at 700∘C NiO NPs have sphere like structure of less than 20 nm particles size value. The strong peak observed at 360.5 nm bandgap emission relates to the bandgap of 3.44 eV which is because of the near band edge emission. [ABSTRACT FROM AUTHOR]

Fluoride (F) in high concentration is very hazardous to human health. The efficacy of nickel oxide nanoparticles (NiO NPs) was investigated in this research as an adsorbent for the elimination of fluoride from aqueous solutions. The effects of pH, contact time, initial concentration of F, and adsorbent dosage on the performance of NiO NPs in the removal of fluoride from aqueous solutions were investigated at room temperature. Langmuir, Freundlich, Temkin, Koble-Corrigan, and Redlich-Peterson adsorption isotherms were employed for the analysis of the adsorption process. Maximum adsorption was achieved at 60 min at pH 5, an adsorbent dosage of 0.02 g/L, and an initial fluoride concentration of 20 mg/L. The results also showed that fluoride adsorption by NiO NPs was more compatible with the Freundlich isotherm (R² = 0.999). and that the process followed the pseudo-second-order kinetic, Ho (type I) (R² = 0.9999 and R² = 0.9997 at 20 and 25 mg/L fluoride concentrations, respectively). From the results obtained, it can be concluded that NiO NPs can be used with high efficiency for fluoride removal. [ABSTRACT FROM AUTHOR]

In this study, nickel oxide nanoparticles have been synthesized through the utilization of a sol-gel approach that contained various temperatures. Chitosan has been appointed to perform polymerization and function as an endpoint agent throughout this project to grow the particles, as well as carrying out the procedures of preventing agglutination, increasing stability, and reducing toxicity, respectively. Phase study, morphology, and determining the structure of nickel oxide nanoparticles have been evaluated by the means of FTIR, XRD, UV-VIS, TGA/DTA, FESEM/EDX, and VSM analyzes. In addition, the photocatalytic effects of nickel oxide nanoparticles on methylene blue (MB) degradation have been investigated and in accordance with the obtained results, they contain great potential as photocatalysts under UV light. The XRD studies have confirmed that the nanoparticles seem to accommodate a face-centered cubic (fcc) crystalline structure and a space group (Fm 3 m). The range of phase-formation temperature of NiO-NPs has been obtained from the TGA/DTA analyses. The VSM examination has shown the superparamagnetism quality of the sample that had been synthesized at 500 °C. To further analyze the safety of NiO-NPs, the evaluation of their biocompatibility on human cancer U87MG cell lines has been performed by the means of MTT assay, which has indicated cell toxicity at concentrations up to 8 μg/mL. Image 1082 • An eco-friendly and cost-effective biosynthetic procedure for NiO-NPs. • NiO-NPs as a great photocatalyst for degradation of methylene blue. • Low cell bio-toxcity of the NiO-NPs. [ABSTRACT FROM AUTHOR]

Background: The correlation of physico-chemical properties with mechanisms of toxicity has been proposed as an approach to predict the toxic potential of the vast number of emerging nanomaterials. Although relationships have been established between properties and the acute pulmonary inflammation induced by nanomaterials, properties' effects on other responses, such as exacerbation of respiratory allergy, have been less frequently explored. Methods: In this study, the role of nickel oxide (NiO) physico-chemical properties in the modulation of ovalbumin (OVA) allergy was examined in a murine model. Results: 181 nm fine (NiO-F) and 42 nm ultrafine (NiO-UF) particles were characterized and incorporated into a time course study where measured markers of pulmonary injury and inflammation were associated with NiO particle surface area. In the OVA model, exposure to NiO, irrespective of any metric was associated with elevated circulating total IgE levels. Serum and lung cytokine levels were similar with respect to NiO surface area. The lower surface area was associated with an enhanced Th2 profile, whereas the higher surface area was associated with a Th1-dominant profile. Surface area-normalized groups also exhibited similar alterations in OVA-specific IgE levels and lung neutrophil number. However, lung eosinophil number and allergen challenge-induced alterations in lung function related more to particle size, wherein NiO-F was associated with an increased enhanced pause response and NiO-UF was associated with increased lung eosinophil burden. Conclusions: Collectively, these findings suggest that although NiO surface area correlates best with acute pulmonary injury and inflammation following respiratory exposure, other physico-chemical properties may contribute to the modulation of immune responses in the lung. [ABSTRACT FROM AUTHOR]

Nickel oxide nanoparticles (NiO NPs) are utilized in various industries and their release into the environment may lead to the pollution of agricultural areas. However, assessing the toxicity of NiO NPs in major food crops is difficult due to the limited information available on their toxicity. The present investigation was carried out to evaluate how NiO NPs affect plant growth, photosynthetic efficiency, and phytochemical content, as well as changes at the transcriptional level of these phytochemicals in Chinese cabbage seedlings. Chlorophyll, carotenoid, and sugar contents were reduced, while proline and the anthocyanins were significantly upregulated in NiO NPs-treated seedlings. The levels of malondialdehyde, hydrogen peroxide, and reactive oxygen species, as well as peroxidase (POD) enzyme activity, were all enhanced in seedlings exposed to NiO NPs. The levels of glucosinolates and phenolic compounds were also significantly increased in NiO NPs-treated seedlings compared to control seedlings. The expression of genes related to oxidative stress (CAT , POD , and GST), MYB transcription factors (BrMYB28, BrMYB29 , BrMYB34 , and BrMYB51), and phenolic compounds (ANS , PAP1, and PAL) were significantly upregulated. We suggest that NiO NPs application stimulates toxic effects and enhances the levels of phytochemicals (glucosinolates and phenolic compounds) in Chinese cabbage seedlings. • Effect of nickel oxide nanoparticles in Chinese cabbage seedlings was studied. • NiO NPs significantly reduced the shoot and root growth. • Chlorophyll, carotenoid, and sugar contents were decreased. • Enhanced ROS generation and lipid peroxidation levels were observed. • Metabolic and molecular changes occurred in response to NiO NPs treatment. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • NiO x nanoparticles with different concertation of cobalt ions are synthesized. • Co-NiO x layers are fabricated at low-temperature process as a hole transport layer. • The band alignment is optimized by decreased work function of Co-NiO x layer. • The conductivity of Co-NiO x films is improved to 6.20 × 10 - 6 S c m - 1 . • Conversion efficiency is improved to 14.5% using 1 mol% Co-NiO x. Abstract We have synthesized cobalt-doped NiO x nanoparticles containing 0.5, 1, 2, 5 and 10 mol% cobalt ions and have investigated their electronic properties, which can be processed into smooth and pinhole-free layers at low temperature (<150 °C) as hole transport layers (HTLs) for perovskite solar cells (PSCs). We have revealed that the relationship between conductivity of HTLs and hole extraction properties to improve the photovoltaic performance. The thin film of cobalt-doped NiO x nanoparticles showed higher conductivities compared to pristine NiO x nanoparticles. Consequently, PSCs with power conversion efficiencies over 14.5%, an improvement from 11.5% for those with the pristine NiO x -based HTL, have been obtained. This work will contribute to the development of doped metal oxide HTLs, which are processable at low temperature. [ABSTRACT FROM AUTHOR]

Abstract We report an electrode material for supercapacitors composed of nickel oxide (NiO) nanoparticles supported onto radially oriented multi-walled carbon nanotubes (CNTs) using a stainless-steel fine-mesh as the support (AISI:CNT-NiO). CNT scaffolds showed a turbostratic multi-walled structure with an interplanar spacing of 0.32 ± 0.02 nm and a diameter of ∼20–100 nm. NiO nanoparticles exhibited a diameter of ∼2–7 nm. X-ray data confirmed the presence of NiO in the scaffold. A large pseudocapacitive voltage range of 2.0 V was obtained in a 1.0 M Li 2 SO 4 aqueous solution. The main contribution to the overall pseudocapacitance is due to the presence of reversible solid-state surface Faradaic reactions involving the Ni(II)/Ni(III) redox couple. High specific capacitance values of ∼1200 F g−1 at 5 A g−1 for the AISI:CNT-NiO electrode were extracted from galvanostatic discharge curves. Considering the contribution of negative voltages, the specific power and energy determined using cyclic voltammetry exhibited values of ∼140 Wh kg−1 and ∼9 W kg−1, respectively, at 0.02 V s−1. A specific capacitance of ∼1028 F g−1 was obtained at this scan rate. Even after 40,000 cycles carried out under galvanostatic conditions, the symmetric coin cell remained stable with a very high coulombic efficiency of ∼99%, which is a remarkable result. Also, we attributed to carbon nanotubes an extraordinary stability as electron drain on the current collector. The morphology factor analysis revealed that 19% of the electrochemically active surface area is confined to the inner surface regions of the porous nanostructured active layer. A low value of 0.15 mΩ g was extracted for the equivalent series resistance. New insights are presented concerning the true meaning of negative voltages for coin cells. Interesting findings regarding the porous nature of electrodes were elucidated using the impedance technique. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • We have synthesized and characterized 20–25-nm nickel oxide nanoparticles. • Evaluating the cytotoxicity of nickel oxide nanoparticles on HT-29 and SW620 cells. • Monitoring the effect of nickel oxide nanoparticles on morphology of HT-29 cells. • Evaluating the alteration in apoptotic regulatory Bcl-2, Bcl-xL and PARP proteins. • Monitoring the bactericidal potential of nickel oxide nanoparticles. Abstract Despite the extensive implication of nickel oxide nanoparticles (NiO-NPs) in different fields such as biomedical science and industrial manufacturing, their effect on human cancer cells has not been elucidated. In this study, we report a simple process for the preparation of NiO-NPs. X-ray diffraction and transmission electron microscopy were used to characterize the surface architecture and dimension of the synthesized NiO-NPs. The average diameter of the NiO-NPs was approximately 20–25 nm. We used two human colon cancer cell lines, HT-29 and SW620, to assess the nanoparticles' cytotoxicity. The MTT assay showed that the NiO-NPs reduced cell viability of HT-29 and SW620 cell lines. The results of inverted microscopy showed the highest cytotoxic activity with 600 μg/ml concentration of NiO-NPs on HT-29 cells. Western blot assay showed the downregulation of anti-apoptotic Bcl2 and Bcl-xL proteins in HT-29 cells treated with NiO-NPs. Moreover the results demonstrated the induction of PARP (Cleaved) in NiO-NPs treated HT-29 cells which are considered the marker of apoptosis. The NiO-NPs were not demonstrated bactericidal effect on six different bacterial strains tested, implying that the NiO-NPs may not perturb the human normal gut microbiome. The results have showed the promising application of the NiO-NPs in management of cancer in near future. [ABSTRACT FROM AUTHOR]

The rising amount of patients suffering for diabetes mellitus increases the requirements for effective insulin sensors. Carbon materials are a suitable choice for the development of insulin sensors due to their electrochemical characteristics. Pencil graphite electrodes (PGE) represent the trade‐off between price and excellent conductive properties. The modification of PGE by NiO and Ni nanoparticles fixed by chitosan results in surface area enlargement and improved electrocatalytic properties. This paper is focused on the comparison of different properties of Ni and NiO nanoparticles and their effect on redox reaction mechanism of insulin and detection characteristics. The electrode modified by Ni nanoparticles displays linear range of 1 μM–5 μM (R2 0.80), limit of detection (LOD) of 4.34 μM and sensitivity of 0.12 μA/μM. On the other hand, the electrode modified by NiO nanoparticles displays enhanced electrochemical characteristics such as linear range of 0.05 μM–5 μM (R2 0.99), limit of detection of 260 nM and sensitivity of 0.64 μA/μM. These properties make the NiO nanoparticles modified PGE the appropriate candidate for insulin determination. [ABSTRACT FROM AUTHOR]

Rats were exposed to nickel oxide nano-aerosol at a concentration of 2.4 ± 0.4 µg/m3 in a “nose only” inhalation setup for 4 h at a time, 5 times a week, during an overall period of 2 weeks to 6 months. Based on the majority of the effects assessed, this kind of exposure may be considered as close to LOAEL (lowest observed adverse effect level), or even to NOAEL (no observed adverse effect level). At the same time, the experiment revealed genotoxic and allergic effects as early as in the first weeks of exposure, suggesting that these effects may have no threshold at all.

Fig. 1. Schematic diagram of NiO-NPs using Green synthesis approach. [Display omitted] • Green synthesis of NiO-NPs in presence of Cassia Fistula Plant Extract. • To understand morphology, crystalline and elemental composition NiO-NPs characterised using SEM, XRD and EDS. • We have studied NiO-NPs antimicrobial properties against Gram positive and gram-negative bacteria such as S.aureus, S.epidermis,K. pneumonia and E.coli. • Tribological studies also conducted for NiO-NPs. The goal of this study was to synthesize nickel oxide nanoparticles (NiO-NPs) by the sol–gel method, which involved the use of Cassia Fistula is a herbal and medicinal plant. The Cassia Fistula (CF) plant extract acts as a stabilizing and capping agent. Further, NiO-NPs were characterized using UV–Visible spectroscopy (UV–Vis), Powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM) and Energy Dispersive X-Ray Spectroscopy (EDX). According to the results of UV–Visible, the absorption spectroscopy has displayed that the band gap is 3.5 eV. The biological properties were studied for prepared NiO-NPs. The antibacterial testes were examined using different bacterial strains such as Escherichia coli, Staphylococcus aureus and Staphylococcus Epidermis and dose-dependent inhibition response was reported. The tribological tests are carried out using four ball testers in accordance with ASTM D4172-18 requirements. NiO-NPs are utilised as lubricating additives in poly alpha olefin (PAO4) base oil. NiO-NPs in PAO4 at a concentration of 0.5 wt% improved the coefficient of friction, and positive results are observed. [ABSTRACT FROM AUTHOR]

[Display omitted] • MXene has been utilized as the unique modifier for sensing interface fabrication. • NiONPs layer has been electrodeposited on MXene/GCE surface to link to Apt. • Apt was tightly attached to NiONPs/MXene/GCE surface to provide MAMP aptasensor. • The designed aptasensor displayed a wide LDR of 1 pM to 50 mM for MAMP detection. • The obtained LOD (333.3 fM) is the lowest value of all reported MAMP sensors. The concerns about the everyday abuse of narcotic materials, as a great alarm for society, have boosted many demands for sensitive and selective tracing of opiates in human biofluids. Herein, by taking advantage of nickel oxide nanoparticles (NiONPs) and MXene (NiONPs/MXene), an efficient sensing platform has been synthesized. The NiONPs/MXene nanocomposite increased the surface area and embedded many sites to load more aptamer (Apt) molecules as the bioreceptors of methamphetamine (MAMP) on the surface in the providing of the high-performance aptasensor. MAMP was measured by the aptasensor under a wide linear dynamic range from 1 pM to 50 mM with a very low limit of detection (LOD) of 333.3 fM within 40 min by consuming very small quantities of samples (10 µL) for each analysis. The highly selective and sensitive aptasensor was able to satisfactory measure MAMP in human serum, saliva and urine samples. The good repeatability and stability of the aptasensor revealed that the applied strategy may be a promising alternative for MAMP assay in the biofluids and street samples that is highly required as a non-invasive method for legal and clinical organizations. [ABSTRACT FROM AUTHOR]

The combination of graphene and nickel oxide nanoparticles yields nanostructured electrochemical sensor formed a novel kind of structurally uniform and electrocatalytic activity material. In cyclic voltammetry studies, in the presence of epinephrine, nickel oxide / graphene composite modified electrode shows a significantly higher current response for epinephrine oxidation. Based on differential pulse voltammetry technique, the oxidation of epinephrine exhibited the dynamic range between 1.0–1800.0 μM and the detection limit was 0.42 μM. Finally, the resulting sensor was used to detect epinephrine and AC simultaneously in human serum samples.

Zhengwang Cao,1 Yiliang Fang,1 Yonghui Lu,1 Fenghua Qian,2 Qinglong Ma,1 Mingdi He,1 Huifeng Pi,1 Zhengping Yu,1 Zhou Zhou1 1Department of Occupational Health, 2Department of Haematology, Southwest Hospital, Third Military Medical University, Chongqing, People’s Republic of China Abstract: With recent advances in the manufacture and application of nickel oxide nanoparticles (NiONPs), concerns about their adverse effects on the respiratory system are increasing. However, the underlying cellular and molecular mechanisms of NiONP-induced pulmonary toxicity remain unclear. In this study, we focused on the impacts of NiONPs on pulmonary inflammation and investigated whether the NLRP3 inflammasome is involved in NiONP-induced pulmonary inflammation and injury. NiONP suspensions were administered by single intratracheal instillation to rats, and inflammatory responses were evaluated at 3 days, 7 days, or 28 days after treatment. NiONP exposure resulted in sustained pulmonary inflammation accompanied by inflammatory cell infiltration, alveolar proteinosis, and cytokine secretion. Expression of Nlrp3 was markedly upregulated by the NiONPs, which was accompanied by overexpression of the active form of caspase-1 (p20) and interleukin (IL)-1β secretion in vivo. NiONP-induced IL-1β secretion was partially prevented by co-treatment with a caspase-1 inhibitor in macrophages. Moreover, siRNA-mediated Nlrp3 knockdown completely attenuated NiONP-induced cytokine release and caspase-1 activity in macrophages in vitro. In addition, NiONP-induced NLRP3 inflammasome activation requires particle uptake and reactive oxygen species production. Collectively, our findings suggest that the NLRP3 inflammasome participates in NiONP-induced pulmonary inflammation and offer new strategies to combat the pulmonary toxicity induced by NiONPs. Keywords: NLRP3 inflammasome, nickel oxide nanoparticles, inflammation, cytokines

There is growing concern regarding nano-sized material discharge into water bodies and their subsequent toxicity to aquatic lives owing to increasingly rapid development and industrial applications of nanoparticles. This study evaluates the oral prescription of silymarin and Nickel Oxide nanoparticles in rainbow trout with an emphasis on growth indices and digestive enzymes activity. To that end, 1200 fish (3.83±0.01g) were randomly allotted into 8 distinct treatments including control group without any supplemental dietary Nickel Oxide nanopartcles or silymarin and the remaining seven experimental groups comprised of different combinations of Nickel Oxide nanoparticles (0, 100 and 500 mg /kg feed) and silymarin (0 and 1 g /kg feed) in the first and second month of the trial. All treatments were carried out in trplicate and the experiment lasted for 60 days. Results showed that the highest amylase activity was recorded in treatment 6 (16.56±1.00) (0 mg Nickel nanoparticle along with 1 g silymaryn - 500 mg Nickel nanoparticle and 1 g silymarin) which significantly differed from treatments 5 (0 mg Nickel Oxide nanoparticles and 1 mg silymarin-100 mg Nickel Oxide nanoparticles with 1 mg silymarin), 7 and 8 (fed diets containing 100 and 500 mg Nickel Oxide nanoparticles, respectively) (P≤0.05). The highest alkaline protease activity was observed in treatment 1 (0.54±0.05) (without any supplemental Nickel or silymarin), which was significantly different from those of treatments 7 and 8 (P≤0.05). The highest lipase activity was reported for treatment 4 (1.03±0.04) (500 mg Nickel nanoparticle with 1 g silymaryn- 0 mg nanoparticle and 1 g silymarin) which was significantly different from other treatments (P≤0.05). The results showed that simultaneous use of Nickel nanoparticle and silymarin in treatments 3, 4, 5 and 6 led to higher digestive enzymes activities in comparison to treatments 7 and 8. However, growth indices did not show any noticeable differences amongst studied treatments. It seems that in a long term exposure to Nickel Oxide nanoparticles and simoltanoues dietary silymarin inclusion, it would also be possible to observe differences in growth and nutritional indices, requiring furthure clarification.

The desire to electrolyze water at low energy and high kinetics for achieving rapid H 2 production forms the holy grail for the paradigm shift to a sustainable H 2 -driven economy. While alkaline electrolysis is preferred due to the use of earth-abundant catalysts, its sluggish kinetics and high overpotential are the persistent challenges. Addressing this, we demonstrate the coupling of an externally applied magnetic field ( H ext ) to a synergistically designed interface of nanostructured carbon floret with antiferromagnetic NiO nanoflakes that act in unison to achieve rapid hydrogen generation (6.3 N m 3 h -1 W -1 ) that is comparable with existing technologies. Specifically, the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) overpotentials are simultaneously reduced by 10 and 7%, respectively, under the influence of a weak fridge magnet ( H ext = 200 mT). Consequently, ∼11% improvement in the energy efficiency is observed with a 21% reduced cell voltage for overall water splitting. The stability of the system is demonstrated over a prolonged lifetime of ∼95 h. This performance enhancement with H ext for both HER and OER is explained in terms of improved kinetic facility for the reaction and lower resistance of charge transfer pathway. Moreover, the electrocatalyst is seen to retain the improved performance for prolonged usage (∼3 h) even after the removal of the H ext , and hence, it provides an energy-efficient hydrogen and oxygen generation pathway.

In the present work, a novel, simple, and sensitive clozapine (CLZ) sensor was developed based on nickel oxide nanoparticle (NiO)-decorated graphene quantum dot (GQD)-modified glassy carbon electrode (NiO/GQD/GCE). NiO/GQD/GCE was prepared by simple electrodeposition, the electrochemical behavior of CLZ at the surface of the prepared electrode was studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV), and an improved reversibility and increased peak current with negative shift in the oxidation potential were observed at the proposed electrode. The effect of some experimental parameters has been examined, and based on the results, an electron transfer-chemical reaction-electron transfer mechanism has been proposed for CLZ electrooxidation. The differential pulse voltammetric response of the NiO/GQD/GCE was linear to the concentration of CLZ in the range of 3 × 10−9 to 1 × 10−6 M, and the detection limit was found to be 0.55 nM (S/N = 3). The method has been successfully used for the selective determination of the CLZ amount in the pharmaceutical preparations and human serum samples with good accuracy and precision. [ABSTRACT FROM AUTHOR]

Background: Although the production and usage of nanoparticles and their entrance to the ecosystem have increased in last decades, information about their negative impacts on organisms is scarce. We concentrated on the comparison of the toxicological effects of different concentrations of bulk-nickel oxide and nickel oxide nanoparticles (NiO-NPs) on lesser (Lemna minor L.) and giant (Spirodela polyrhiza (L.) Schleid.) duckweeds as two model macrophytes. Methods: The morphology of nickel oxide nanoparticles was studied by scanning electron microscopy (SEM) and transition electron microscopy (TEM). The plant's growth, photosynthetic pigments content, the contents of total phenols, flavonoids and MDA, and the activities of some antioxidant enzymes were investigated as indices to assess the toxicological effects of the NPs on two plant species. Results: The content of photosynthetic pigments in both of the plant species was significantly reduced by high concentration of NiO-NP. Increasing the concentration of the contaminants in the plant species was led to the remarkable enhancement of total phenol and flavonoid and MDA contents. Moreover, increasing the activity of the plant's antioxidant enzymes could reflect high reactive oxygen species (ROS) production after the plant's treatments with the contaminants. Conclusion: The negative effects of the NiO-NPs, especially in high concentrations, on L. minor and S. polyrhiza were more than those of Bulk-NiO. [ABSTRACT FROM AUTHOR]

The controlled synthesis of nickel oxide nanoparticle (NiO NPs) were synthesized by homogeneous precipitation method and have been characterized using UV-visible spectrophotometer, fourier transform-infrared spectroscopy, X-ray diffraction, atomic force microscope, scanning electron microscope and high resolution-transmission electron microscope. The synthesized NiO NPs was spherical in shape with an average size ranged between 3 and 5 nm. Subsequently, synthesis of NiO NPs coated on a bacterial nanowires (BNWs) film pre-cast on a glassy carbon electrode surface and the morphology and nature of the prepared composite was characterized using HR-TEM. The electro-chemical behavior of NiO NPs coated bacterial nanowires (NiO NPs-BNWs) was observed using cyclic voltammetry, linear sweep voltammetry and electrochemical impedance spectroscopy analysis. Highly comparable electrochemical conductivity of NiO NPs-BNWs was observed in this study. The BNWs sample exhibited a polarization resistance (Rp) to be 4457 Ω and the NiO NPs-BNWs sample exhibited polarization resistance (Rp) about 2270.4 Ω. The BNWs exhibited a CPE-T value to be 6.26 µF cm−2 and the NiO NPs-BNWs sample exhibited CPE-T to be 9.32 µF cm−2. The enhancement of peak currents is ascribed to the short heterogeneous electron transfer among the NiO NPs-BNWs. The defined nanolayer provides a novel platform for the next generation electrochemical applications. [ABSTRACT FROM AUTHOR]

In this research, the microwave-assisted method was used for the synthesis of nickel oxide nanoparticles (NiO NPs). The synthesized NiO NPs were characterized using Brunauer–Emmett–Teller surface analyzer, transmission electron microscopy, X-ray diffraction and pHZPC. We found that the specific surface area, total pore volume, average pore diameter and pHZPC of the prepared NiO NPs were 78.37 m² /g, 0.068 cm³ /g, 34.92 Å and 8.1. Also, we examined the adsorption of Bromophenol blue (BB) using NiO NPs at different temperatures (303, 318 and 333 K). Further, we evaluated the impacts of adsorbate concentration, agitation time, temperature and pH. Indeed, the adsorbate concentration of 300 mg/L, temperature of 333 K and pH of 12 at 24 h were observed to be the ideal experimental conditions. Isotherm models of Freundlich and Langmuir were employed and the obtained results revealed that the equilibrium data were described well by Langmuir equation. The highest monolayer capacities of this adsorption were found to be 58.48, 79.37 and 93.46 mg/g at 303, 318 and 333 K. Kinetic models of first order, second order and intra-particle diffusion were used to examine the kinetic experimental data. Thermodynamic factors were determined and the values obtained designate that the adsorption of BB on NiO NPs is endothermic and non-spontaneous processes. [ABSTRACT FROM AUTHOR]

We developed highly selective polyurethane (PU) membranes with incorporated NiO nanoparticles for gas-phase carbon dioxide separation. PU was synthesized with polytetramethylene glycol and isophoronediisocyanate, and 1,4-butandiamine/1,4-butandiol as the chain extender (1:3:2 molar ratio). Mixed matrix membranes (MMMs) composed of PU and NiO nanoparticles were fabricated using the solution casting method. Scanning electron microscopy (SEM) confirmed the even distribution of NiO in the PU matrix at the nanoscale. Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC) were used to examine the phase separation between the soft and hard domains of PU, and the distribution of NiO nanoparticles in both domains. DSC and X-ray diffraction (XRD) pattern confirmed that the crystalline structures in both soft and hard segments are changed by NiO incorporation. The effects of NiO nanoparticles on the gas permeability, diffusivity, and solubility of pure CO 2 , CH 4 , O 2 , and N 2 gases were studied at various temperatures and feed pressures. A large increase in the CO 2 /N 2 permselectivity with a simultaneous reduction in the gas permeability of CH 4 , O 2 , and N 2 was observed. When the NiO content was low (1 wt%), the CO 2 /N 2 permselectivity increased by 79.21%, and the CO 2 permeability increased by 1.57%. Increasing the nanoparticle load to 5 wt% increased the CO 2 /N 2 permselectivity by 161.1%, while the CO 2 permeability was decreased by 3.31%. [ABSTRACT FROM AUTHOR]

Context:Nickel oxide (NiO) nanoparticles (NPs) with appropriate surface chemistry have been widely used for their potential new applications in biomedical industry. Increased usage of these NPs enhances the chance of exposure of personnel involved in the work place. Objective:This study was designed to assess the ability of NiO NPs to cause biochemical alterations post-acute oral exposure in female Wistar rats. Materials and methods:Rats were administered with 125, 250, and 500 mg/kg doses of NiO NPs for haematological, biochemical, and histopathological studies. Biodistribution patterns of NiO NPs in female Wistar rats were also monitored. Results:NiO NPs caused significant (p < 0.01) inhibition of RBC and brain AchE of treated rats at the high dose. Activation of the hepatotoxicity marker enzymes, aminotransferases, was recorded in serum and liver, whereas inhibition was observed in kidney. The activity of antioxidant enzymes was also altered by NiO NPs in a dose-dependent manner and found to be significant at the high dose of exposure. Conclusions:This study revealed that exposure to nanosized NiO particles at acute doses may cause adverse changes in animal biochemical profiles. Further, thein vivostudies on toxicity evaluation help in biomonitoring of the potential contaminants. [ABSTRACT FROM AUTHOR]

The unique properties of nickel oxide nanoparticles (NiO-NPs) distinguish it from traditional nickel containing materials, and enable its industrial application as an advanced nanomaterial. Despite the benefits, the in vivo toxicological studies on NiO-NPs have been mainly focused on its pulmonary pathology. However, NiO-NPs exposure via oral route and its subsequent toxic effects in exposed animals are still lacking. Hence, we evaluated the NiO-NPs oral toxicity in male Wistar rats. NiO-NPs induced significant increase in chromosomal aberrations (CAs), micronuclei (MN) formation and, DNA damage in rats. Flow cytometric analysis showed apoptosis, ROS generation and dysfunction of mitochondrial membrane potential ( ΔΨm ). Imbalance of antioxidant enzymes, along with histological alterations was found in liver. Taking together, these results unequivocally suggested that NiO-NPs induced toxicity was through cyto-genetic alterations, oxidative stress, apoptosis and liver toxicity. The western blotting data validated the interplay of p53 and MAPKAPK-2 signalling via activation of caspases 8, 3, cyto c, pro-apoptotic bax and anti-apoptotic bcl-2 proteins. [ABSTRACT FROM AUTHOR]

Rats were exposed to nickel oxide nanoparticles (NiO-NP) inhalation at 0.23 ± 0.01 mg/m3 for 4 h a day 5 times a week for up to 10 months. The rat organism responded to this impact with changes in cytological and some biochemical characteristics of the bronchoalveolar lavage fluid along with a paradoxically little pronounced pulmonary pathology associated with a rather low chronic retention of nanoparticles in the lungs. There were various manifestations of systemic toxicity, including damage to the liver and kidneys; a likely allergic syndrome as indicated by some cytological signs; transient stimulation of erythropoiesis; and penetration of nickel into the brain from the nasal mucous membrane along the olfactory pathway. Against a picture of mild to moderate chronic toxicity of nickel, its in vivo genotoxic effect assessed by the degree of DNA fragmentation in nucleated blood cells (the RAPD test) was pronounced, tending to increasing with the length of the exposure period. When rats were given orally, in parallel with the toxic exposure, a set of innocuous substances with differing mechanisms of expected bioprotective action, the genotoxic effect of NiO-NPs was found to be substantially attenuated.

A simple and highly selective electrochemical method using a glassy carbon electrode (GCE) modified with graphene oxide (GO) and nickel oxide nanoparticles (NiONPs) was developed for the simultaneous determination of paracetamol (PAR) and ciprofloxacin (CIP). The electrochemical characterisation of the modified GCE was performed by cyclic voltammetry and electrochemical impedance spectroscopy. The morphological characterisation of the GO and NiONPs was performed by scanning electron microscopy and transmission electron microscopy. Under optimised conditions, using square wave voltammetry, the simultaneous determination of PAR and CIP using the NiONPs-GO-CTS: EPH/GCE sensor shows a linear concentration range from 0.10 to 2.9 µmol L −1 and 0.040–0.97 µmol L −1 , with detection limits of 6.7 and 6.0 nmol L −1 , respectively. The NiONPs-GO-CTS: EPH/GCE sensor showed good reproducibility, repeatability and stability. Furthermore, the proposed method was successfully applied for the simultaneous determination of PAR and CIP in synthetic biological fluid samples. [ABSTRACT FROM AUTHOR]

Nanotechnology based therapeutics has emerged as a promising approach for augmenting the activity of existing antimicrobials due to the unique physical and chemical properties of nanoparticles (NPs). Nickel oxide nanoparticles (NiO-NPs) have been suggested as prospective antibacterial and antitumor agent. In this study, NiO-NPs have been synthesized by a green approach using Eucalyptus globulus leaf extract and assessed for their bactericidal activity. The morphology and purity of synthesized NiO-NPs determined through various spectroscopic techniques like UV-Visible, FT-IR, XRD, EDX and electron microscopy differed considerably. The synthesized NiO-NPs were pleomorphic varying in size between 10 and 20 nm. The XRD analysis revealed the average size of NiO-NPs as 19 nm. The UV-Vis spectroscopic data showed a strong SPR of NiO-NPs with a characteristic spectral peak at 396 nm. The FTIR data revealed various functional moieties like C=C, C–N, C–H and O–H which elucidate the role of leaf biomolecules in capping and dispersal of NiO-NPs. The bioactivity assay revealed the antibacterial and anti-biofilm activity of NiO-NPs against ESβL (+) E. coli , P. aeruginosa , methicillin sensitive and resistant S. aureus . Growth inhibition assay demonstrated time and NiO-NPs concentration dependent decrease in the viability of treated cells. NiO-NPs induced biofilm inhibition was revealed by a sharp increase in characteristic red fluorescence of PI, while SEM images of NiO-NPs treated cells were irregular shrink and distorted with obvious depressions/indentations. The results suggested significant antibacterial and antibiofilm activity of NiO-NPs which may play an important role in the management of infectious diseases affecting human health. [ABSTRACT FROM AUTHOR]

Nickel oxide nanoparticles (NiO-NPs) are used in many industrial sectors including printing inks, ceramics and catalysts, and electrical and electronics industry because of their magnetic and optical properties. However, there has been still a serious lack of information about their toxicity at the cellular and molecular levels on nervous system. For that, we aimed to investigate the in vitro toxic potentials of NiO-NPs in neuronal (SH-SY5Y) cells. The particle characterisation, cellular uptake and morphological changes were determined using Transmission Electron Microscopy, dynamic light scattering and Inductively Coupled Plasma-Mass Spectrometry. Then, the cytotoxicity was evaluated by MTT and neutral red uptake assays, the genotoxicity by comet assay, the oxidative potentials by the determination of malondialdehyde, 8-hydroxy deoxyguanosine, protein carbonyl, and glutathione levels with Enzyme-Linked Immune Sorbent Assays, and the apoptotic potentials by Annexin V-FITC apoptosis detection assay with propidium iodide. According to the results, it was observed that NiO-NPs (15.0 nm ± 4.2–38.1 nm); (i) were taken up by the cells in concentration dependent manner, (ii) caused 50% inhibition in cell viability at ≥229.34 μg/mL, (iii) induced some morphological changes, (iv) induced dose-dependent DNA damage (3.2–11.0 fold) and apoptosis (80–99%), (v) significantly induced oxidative damage. In conclusion, our results support the hypothesis that NiO-NPs affect human health especially neuronal system negatively and should raise the concern about the safety associated with their applications in consumer products. [ABSTRACT FROM AUTHOR]

Nano-particle oxides of transition metals have attracted materials scientists. These materials have exceptional properties which stimulate many advanced applications. As like all other transition metal oxide, nickel oxide has been especially investigated in the degradation of several environmental pollutants due to its properties. The nickel oxide was synthesized by electrochemical reduction method using tetra-hexyl ammonium bromide as structure directing agent in an organic medium viz. tetra hydro furan and acetonitrile in 1:4 ratio by different current densities 10 and 14 mA/cm. Such nanoparticles were prepared using simple electrolysis cell in which the sacrificial anode is a commercially available nickel metal sheet and platinum (inert) sheet act as a cathode. The synthesized nickel oxide nanoparticles were characterized by using UV-visible spectroscopy, X-ray diffraction (XRD), scanning electron microscopy, energy dispersive spectroscopy (EDS) and transmission electron microscope (TEM) analysis techniques. TEM analysis proved a cubic structure with size of 25-30 nm which was in agreement with the result calculated from the XRD analysis. EDS analysis revealed the presence of Ni and O element. The nanoparticles were tested for antifungal activity against human pathogens like A. alternaria, A. niger, F. oxysporum, etc., which showed excellent antifungal properties. [ABSTRACT FROM AUTHOR]

Increasing use of nickel oxide (NiO) nanoparticles in different applications results in high occupational and environmental exposure to them. However, the effect of NiO nanoparticles on human health is still poorly documented. It was aimed to investigate the toxic potentials of NiO nanoparticles on NRK-52E kidney epithelial cells. The following assays were used: the nanoparticle characterization by transmission electron microscopy (TEM) and dynamic light scattering (DLS); the determination of cellular uptake and morphologic changes by TEM and inductively coupled plasma-mass spectrometry (ICP-MS); MTT and neutral red uptake (NRU) assays for cytotoxicity; comet assay for genotoxicity; the determination of malondialdehyde (MDA), 8-hydroxydeoxyguanosine (8-OHdG), protein carbonyl (PC) and glutathione (GSH) levels by enzyme-linked immune sorbent assays (ELISA) for the potential of oxidative damage; and Annexin V-FITC apoptosis detection assay with propidium iodide (PI) for apoptosis. The nanoparticles were taken up by the cells and induced dose-dependent DNA damage by comet assay and oxidative damage evidenced by increasing levels of MDA, 8-OHdG, PC and depletion of GSH. At ≥294.0 μg/mL concentration, NiO nanoparticles caused 50% inhibition in cell viability by the cytotoxicity assays. Also, they showed apoptotic/necrotic effects on the cells as well as some morphological changes. We have indicated that their cellular damage effects should raise concern about the safety associated with their applications in consumer products. [ABSTRACT FROM AUTHOR]

A three-dimensional reduced graphene oxide aerogel with embedded nickel oxide nanoparticles was prepared by a one-step self-assembly reaction in a short time. The nanoparticles could be captured into the interior of reduced graphene oxide network during the formation of the three-dimensional architecture. The composite exhibited porosity, good biocompatibility, and abundant metal affinity binding sites. The aerogel was used to isolate ovalbumin selectively from egg white, and favorable adsorption was achieved at pH 3. An adsorption efficiency of 90.6% was obtained by using 1 mg of the composite for adsorbing 70 μg/mL of ovalbumin in 1.0 mL of sample solution, and afterwards a recovery of 90.7% was achieved by using an eluent of 1.0 mL Britton-Robinson buffer solution at pH 5. After the adsorption/desorption, ovalbumin showed no change in the conformation. The adsorption behavior of ovalbumin on the reduced graphene oxide composite well fitted to the Langmuir adsorption model, and a corresponding theoretical maximum adsorption capacity was 1695.2 mg/g. A sodium dodecyl sulfate polyacrylamide gel electrophoresis assay demonstrated that the aerogel could selectively isolate ovalbumin from chicken egg white. [ABSTRACT FROM AUTHOR]

Nickel oxide nanoparticles were grafted on reduced graphene oxide via simultaneous reduction of graphene oxide and nickel salt in a single step reaction. The synthesized material (rGO/NiO) was found to be efficient visible light active photocatalyst for the reduction of nitroaromatic derivatives to their corresponding amino compounds. Hydrazine monohydrate provided necessary protons and electrons for the targeted reaction. After completion of the reaction, the photocatalyst could readily be recovered by simple external magnet and could be reused for six runs without any significant loss of its activity. More importantly, the photocatalyst did not show any leaching during the reaction as confirmed by ICP-AES analysis of the recovered catalyst. [ABSTRACT FROM AUTHOR]

The significant hydrogen content and energy density in addition to the liquid nature and the high boiling point of ethylene glycol (EG) have recommended it as a potential replacement for hydrogen in proton exchange membrane fuel cells (PEMFCs). We herein report an enhanced electrocatalytic activity of EG electro-oxidation (EGO) in alkaline medium on a binary catalyst composed of platinum nanoparticles (nano-Pt) and nickel oxide nanoparticles (nano-NiOx) and assembled electrochemically on a glassy carbon (GC) electrode. The electrocatalytic activity of this catalyst towards EGO depended significantly on the loading level of the constituting ingredients of the catalyst, electrolyte acidity (pH) and the operating temperature. Several tools of electrochemical and materials characterization including the cyclic voltammetry (CV), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) were all employed to confirm the successful deposition, to probe the relative ratio of the catalyst's ingredients and to evaluate the surface topography, bulk composition and structure of the proposed catalyst. The results indicated a volcano-shaped dependence of the catalytic activity towards EGO on the loading level of nano-pt and nano-NiOx in the recommended catalyst. The investigation succeeded to optimize the synthetic procedure to reduce the amount of the precious Pt in the catalyst while maintaining a better catalytic activity than that obtained at the bare Pt surfaces. Interestingly, adding nano-NiOx to the catalyst's ingredients (NiOx/Pt/GC) ended up with a significant lowering (13.90 kJ mol −1 ) in the activation energy ( E a ) of EGO in comparison to that ( E a = 18.83 kJ mol −1 ) obtained at the Pt/GC electrode. [ABSTRACT FROM AUTHOR]

[Display omitted] • High crystalline NiO NPs were synthesised using different alkaline actuators and green extract of Moringa oliefera leaves. • The synthesised samples have high physiochemical and optical properties. • The photocatalytic efficiency was reached till ∼ 98 % for green synthesised samples within 100 min under UV irradiation. • The in vitro biological studies show the clinical applications of prepared NiO NPs. Nickel oxide nanoparticles (NiO NPs) were produced by employing a sonochemical approach with the use of three distinct alkaline activators, namely sodium hydroxide (NaOH), potassium hydroxide (KOH), and ammonium hydroxide (NH 3 OH) and as well as extract of Moringa oleifera leaves. The physiochemical and optical characteristics of sonochemically synthesized nanoparticles were examined comparatively with green synthesized NiO NPs. The comparison rendered the high-yield production of NiO nanoparticles achieved in the green synthesis process that includes 63.29 % of the total nickel precursor employed. The prepared samples were further investigated for their photocatalytic activity for safranin and methyl orange dye. Thus, the Moringa oleifera mediated NiO NPs have achieved the highest degradation efficiency of 92.75 % and 98.02 % against the corresponding dyes. Including NiO NPs in DPPH antioxidant activity have higher free radical scavenging efficiency of 95.3 %. The reduction of growth against specific S. aureus and E. coli bacteria at low concentrations of NiO-NPs was coined for various in-vitro biological and clinical applications. [ABSTRACT FROM AUTHOR]

[Display omitted] • Green synthesis of NiO/rGO has been successfully prepared using Pometia pinnata leaves extract as single bioreductor; • NiO/rGO showed the dispersed NiO nanoparticles in rGO matrices with particles size ranging at 10–30 nm; • NiO/rGO showed an excellent photocatalytic activity in photocatalytic oxidation of tetracycline; • NiO/rGO expresses antibacterial activity against Staphylococcus aureus and Eschericia coli with low minimum inhibitory concentration. Photocatalytic oxidation is one of the effective methods in pharmaceutical wastewater treatment. Among some photocatalysts, NiO-based nanocomposites with high photoactivity are recognized as stable and feasible materials for this purpose. In this work, an environment-friendly approach for synthesizing of reduced graphene oxide/nickel oxide nanocomposites Nickel oxide-modifed reduced graphene oxide (NiO/rGO) prepared by green synthesis method and study on its photocatalytic activity has been performed. The green method for NiO nanoparticles (NiO NPs) was conducted by using NiCl 2 with Tinosphora cordifolia stem extract under ultrasound-assisted reaction, and the obtained NPs was dispersed hydrothermally into rGO powder. Physicochemical characterization of materials including X-ray diffraction, scanning electron microscopy, transmission electron microscope, X-ray photoelectron spectroscopy, and UV–Visible diffuse reflectance spectroscopy analyses were investigated, meanwhile, for photocatalytic activity, the removal of tetracycline over photooxidation process. The results show that NiO/rGO material provides high performance as photocatalyst with the higher band gap energy (3.28 eV) than NiO NPs (3.01 eV) along with the smaller NiO crystallite size (42 nm) in the composite than in NiO NPs (40 nm). NiO/rGO composite also shows excellent photocatalytic activity feature for tetracycline degradation as it is about 100 % tetracycline removal achieved at 30 min under both UV and visible light illumination. The rGO contribution in the photocatalytic activity is expressed by the higher turnover number (6.67) in both light sources than NiO NPs (0.55 and 0.41 under UV and visible light). NiO/rGO expresses the antibacterial activity against Staphylococcus aureus and Eschericia coli as shown by low minimum inhibitory concentrations (MIC). The MIC against S. aureus is < 0.5 μg/mL, meanwhile the MIC against E.coli is 2 μg/mL. Generally speaking, the green synthesized NiO/rGO which could be advantageous as functional material especially as photocatalyst for pharmaceutical industrial wastewater treatment and antibacterial agent. [ABSTRACT FROM AUTHOR]

In the present work we synthesize nickel oxide nanoparticles (NiO NPs) using Rhododendron arboretum (flower) (RNi), Tinospora cordifolia (stems) (GNi), Corylus jacquemontii (seeds) (CNi), and Nardostachys jatamansi (roots) (NNi) extracts by co-precipitation method. The synthesized NiO NPs were characterized in detail in terms of their morphological, crystalline nature, structural and antiproliferative activity against rat skeletal myoblast (L-6) cell lines. Morphological studies confirmed the formation of nanoparticles, while the structural and compositional characterization revealed the well-crystallinity and high purity of the synthesized nanoparticles. For biological applications and cytotoxicity examinations of the synthesized NPs, the rat skeletal myoblast (L-6) cell lines were subjected to study. By detailed cytotoxic investigations, it was observed that among the four kinds of NiO NPs prepared through different plant extracts, the Tinospora cordifolia (stems) showed strong antiproliferative activity against rat skeletal myoblast (L-6) cell lines and the calculated IC 50 was 1.671 mg/mL. The observed antiproliferative activity towards different NiO NPs were in the order of GNi > NNi > RNi > CNi. The present studies demonstrate that simply synthesized NiO can efficiently be used as antiproliferative agents. • Green synthesis of NiO nanoparticles using various plant extracts, i.e. Rhododendron arboretum (RNi) , Tinospora cordifolia (GNi) , Corylus jacquemontii (CNi) , and Nardostachys jatamansi (NNi). • Enhanced antiproliferative activity of different NiO NPs towards Rat Skeletal myoblast (L-6) cell lines. • The observed antiproliferative activity towards different NiO NPs were in the order of GNi > NNi > RNi > CNi. [ABSTRACT FROM AUTHOR]