Exposure to Nickel Oxide Nanoparticles Induces Acute and Chronic Inflammatory Responses in Rat Lungs and Perturbs the Lung Microbiome

Nickel oxide nanoparticles (NiO NPs) are highly redox active nanoparticles. They can cause acute and chronic inflammation in rat lungs. Unlike the gut microbiome, the association between the lung microbiome’s role and pulmonary inflammatory response to inhaled nanoparticles remains largely unexplored. We aimed to explore the interaction between the lung microbiome and inflammatory responses in rats exposed to NiO NPs. Thirty female Wistar rats were randomly categorized into control and low- (50 cm2/rat), and high- (150 cm2/rat) dose NiO NPs exposure groups. NiO NPs were intratracheally instilled, and cytological, biochemical, proinflammatory cytokine, and lung microbiome analyses of bronchoalveolar lavage fluid were performed at 1 day and 4 weeks after instillation. NiO NPs caused a neutrophilic and lymphocytic inflammatory response in rat lung. We demonstrated that exposure to NiO NPs can alter the lung microbial composition in rats. In particular, we found that more Burkholderiales are present in the NiO NPs exposure groups than in the control group at 1 day after instillation. Dysbiosis in the lung microbiome is thought to be associated with acute lung inflammation. We also suggested that Burkholderiales may be a key biomarker associated with lung neutrophilic inflammation after NiO NPs exposure.

Phase-Controlled NiO Nanoparticles on Reduced Graphene Oxide as Electrocatalysts for Overall Water Splitting

Efficient water electrolysis is one of the key issues in realizing a clean and renewable energy society based on hydrogen fuel. However, several obstacles remain to be solved for electrochemical water splitting catalysts, which are the high cost of noble metals and the high overpotential of alternative catalysts. Herein, we suggest Ni-based alternative catalysts that have comparable performances with precious metal-based catalysts and could be applied to both cathode and anode by precise phase control of the pristine catalyst. A facile microwave-assisted procedure was used for NiO nanoparticles anchored on reduced graphene oxide (NiO NPs/rGO) with uniform size distribution in ~1.8 nm. Subsequently, the Ni-NiO dual phase of the NPs (A-NiO NPs/rGO) could be obtained via tailored partial reduction of the NiO NPs/rGO. Moreover, we demonstrate from systematic HADDF-EDS and XPS analyses that metallic Ni could be formed in a local area of the NiO NP after the reductive annealing procedure. Indeed, the synergistic catalytic performance of the Ni-NiO phase of the A-NiO NPs/rGO promoted hydrogen evolution reaction activity with an overpotential as 201 mV at 10 mA cm−2, whereas the NiO NPs/rGO showed 353 mV. Meanwhile, the NiO NPs/rGO exhibited the most excellent oxygen evolution reaction performance among all of the Ni-based catalysts, with an overpotential of 369 mV at 10 mA cm−2, indicating that they could be selectively utilized in the overall water splitting. Furthermore, both catalysts retained their activities over 12 h with constant voltage and 1000 cycles under cyclic redox reaction, proving their high durability. Finally, the full cell capability for the overall water electrolysis system was confirmed by observing the generation of hydrogen and oxygen on the surface of the cathode and anode.

The Variation Effect of Mg-doped NPs Prepared by Sol-Gel Method on its Structural Properties and Biological Activities

In this paper, we reported the synthesis of NiO NPs and Mg doped-NiO NPs using the facile sol-gel method. Besides, the influence of the variation of Mg dopant on the structural, morphological and optical properties of the prepared Mg-NiO NPs was studied. The synthesized Mg-NiO NPs nanoparticles were characterized by X-Ray Diffraction Analysis (XRD), Energy Dispersive X-ray Spectroscopy (EDS), Fourier-Transform Infrared Spectroscopy (FTIR), Field-Emission Scanning Electron Microscopy (FE-SEM), and UV-Vis spectrophotometer. The X-ray diffraction confirmed the formation of the cubic structure of Mg doped-NiO NPs after doping with the magnesium. The increase in the crystal size was observed with the increase in the concentration of the Mg dopant element. The FESEM images reveal the formation of nickel oxide through the appearance of spherical clusters, while the hybrids appear as wrinkled surface covered with spherical particles of magnesium. The UV-Vis spectrum showed a shift towards shorter wavelengths with an increase in the concentration of the Mg dopant element due to the quantum confinement effect. The hemolysis activity study showed that NiO NPs had a low hemolysis percentage of 1.47% and increased with increasing concentration. While, increasing of the RBC hemolysis (5.9%) after NiO doped with Mg. The antibacterial activity was studied against S. aureus and P. aeruginosa bacteria, and indicated the highest growth inhibition zones of Mg-doped NiO NPs as compared with NiO NPs against of Staphylococcus aureus and Pseudomonas aeruginosa, respectively.

Influence of Various Concentrations of Cetyltrimethylammonium Bromide on the Properties of Nickel Oxide Nanoparticles for Supercapacitor Application

In this paper, the impact of the crystallite sizes of nickel oxide nanoparticles (NiO NPs) on their efficiency for electrochemical capacitors (EC) has been investigated. NiO NPs were prepared without and with low and high concentrations (0.02[Formula: see text]M and 0.1[Formula: see text]M) of cetyltrimethylammonium bromide (CTAB) using the hydrothermal process that represent NiO, NiO-1, NiO-2, respectively. The crystallite size of NiO, NiO-1, NiO-2 NPs was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM) analysis. The thermogravimetry/differential thermal analysis (TG/DTA) was used to investigate the thermal observation of as-prepared precursor to transform as NiO NPs. HRTEM revealed spherical seed-like morphologies, which consist of aggregated NiO-1 NPs with an average particle size of 9[Formula: see text]nm. The NiO-1 shows the large specific capacitance value of 168[Formula: see text]Fg[Formula: see text] at a current density of 0.5[Formula: see text]Ag[Formula: see text] compared with other NiO and NiO-2 NPs. The study suggests that the low concentration of surfactant CTAB of NiO NPs plays an important role in supercapacitor applications because of the smaller crystallite sizes of the materials as well as a large number of active sites for faradic reaction.

Characterization of Nickel Oxide Nanoparticles Synthesized under Low Temperature

In this study, ultrafine nickel oxide nanoparticles (NiO NPs) were well synthesized using a simple wet chemical method under low temperature, 300 °C. An Ni(OH)2 precursor was well precipitated by dropping NH4OH into an Ni(Ac)2 solution. TG-DTA showed that the weight of the precipitate decreases until 300 °C; therefore, the precursor was heat-treated at 300 °C. X-ray diffraction (XRD) patterns indicated that hexagonal-structured NiO NPs with (200) preferred orientation was synthesized. In addition, BET specific surface area (SSA) and HRTEM analyses revealed that spherical NiO NPs were formed with SSA and particle size of 60.14 m2/g and ca. 5–15 nm by using the low temperature method. FT-IR spectra of the NiO NPs showed only a sharp vibrating absorption peak at around 550 cm−1 owing to the Ni-O bond. Additionally, in UV-vis absorption spectra, the wavelength for absorption edge and energy band gap of the ultrafine NiO NPs was 290 nm and 3.44 eV.

N and Fe doped NiO nanoparticles for enhanced photocatalytic degradation of azo dye methylene blue in the presence of visible light

Pure NiO, N-doped, Fe-doped, N and Fe codoped NiO NPs were fabricated via a precipitation process. The powder X-ray diffraction (XRD) revealed the face centered cubic phase of NiO products. The full width at half maximum (FWHM) of the XRD peak was steadily enlarged with the order of elements N, Fe, N/Fe doped to NiO, and shifted towards a greater angle due to decrease in grain size, as shown by XRD. The average crystallite size of NiO products was calculated, ranging from 6.67 to 3.76 nm, according to the Debye Scherrer formula. The scanning electron microscopy (SEM) demonstrated considerable morphological changes in the produced nanoparticles, including those directed to rock-like geometries (NiO and Fe/NiO nanoparticles) while gas covered-nanocrystals (N/NiO and N/Fe/NiO nanoparticles) were formed using precipitation method. The particle size range of 10–50 nm was estimated using the bar scale in transmission electron microscopy (TEM) pictures. The elemental composition of Ni, O, Fe and N atoms in the respected samples was analyzed by Energy Dispersive X-Ray Analysis (EDX). Photoluminescence (PL) showed band edge emission at 370 nm. The band edge-absorption peak, which is caused by electronic transitions between energy levels, is determined to be in the range 314–325 nm. A UV–Vis analysis found an energy gap amid 3.2 eV and 2.5 eV. The chemical condition of the Fe and N doped NiO composites were validated using XPS. Using visible photo application of undoped and doped NiO NPs, the degradation of an azo dye termed methylene blue was examined. It was N/Fe/NiO (79.8%), Fe/NiO (76%), N/NiO (73%), and NiO (62%) throughout the 6 h irradiation duration. Increased production of OH• radicals was detected in fluorescence tests using terephthalic acid (TA) for N/Fe/NiO NPs, indicating the higher photo-degradation described. Furthermore, the degradation trends of both undoped and doped NiO NPs closely matched the pseudo first order kinetics, according to the kinetic analysis. There was also a suggestion for a thorough MB breakdown mechanism.

Biochemical and histological alterations induced by nickel oxide nanoparticles in the ground beetle Blaps polychresta (Forskl, 1775) (Coleoptera: Tenebrionidae)

The present study evaluates the effect of nickel oxide nanoparticles on some biochemical parameters and midgut tissues in the ground beetle Blaps polychresta as an indicator organism for nanotoxicity. Serial doses of the NiO-NPs colloid (0.01, 0.02, 0.03, 0.04, 0.05, and 0.06 mg/g) were prepared for injecting into the adult beetles. Insect survival was reported daily for 30 days, and the sublethal dose of 0.02 mg/g NiO-NPs was selected for the tested parameters. After the treatment, nickel was detected in the midgut tissues by X-ray microanalysis. The treated group demonstrated a significant increase in aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities when compared to the untreated group. However, the treated group demonstrated a significant decrease in ascorbate peroxidase (APOX) activity when compared to the untreated group. Histological and ultrastructural changes in the midgut tissues of treated and untreated beetles were also observed. The current findings provide a precedent for describing the physiological and histological changes caused by NiO-NPs in the ground beetle B. polychresta.

Physicochemical, Photocatalytic, Antibacterial, and Antioxidant Screening of Bergenia Ciliata Mediated Nickel Oxide Nanoparticles

This study was planned to synthesize a multifunctional nanomaterial that can effectively encounter the organic pollutants, multidrug-resistant bacteria and reactive free radicals. The Bergenia ciliate (B. ciliate) leaves extract was used as a reducing and capping agent for the synthesis of nickel oxide nanoparticles (NiO NP). The physicochemical properties were studied through X-ray diffractometre (XRD), energy dispersive X-ray (EDX), scanning electron microscopy (SEM), transmission electron microscopy (TEM), UV-visible and Fourier transform infrared (FTIR) spectroscopies. The highly crystalline monoclinic NiO NPs were synthesized with crystallite size of 27.45 nm. The average particle size derived from TEM micrograph was 49.35 nm whereas the calculated band gap for NiO NPs was 3.78 eV. The photocatalytic study shows that 92.17% of the rhodamine 6G (Rh-6G) was efficiently degraded in the presence of NiO NPs. The agar well diffusion method was applied to examine the antibacterial activity of NiO NPs and the activity was found higher against Gram-negative bacteria (GNB) as compared to Gram-positive bacteria (GPB). The ABTS free radical scavenging activity was also performed, however, the activity was found less than the standard.