ZnO nanopowders and their excellent solar light/UV photocatalytic activity on degradation of dye in wastewater

Low-cost and scalable preparation,high photocatalytic activity,and convenient recycle of Zn O nanopowders(NPs)would determine their practical application in purifying wastewater.In this contribution,ZnO NPs were scalably synthesized via the simple reaction of Zn powder with H_2O vapor in autoclave.The structural,morphological and optical properties of the samples were systematically characterized by X-ray diffraction,scanning electron microscopy,Fourier transform infrared spectra,transmission electron microscopy,Micro-Raman,photoluminescence,and ultraviolet-visible spectroscopy.The as-prepared Zn O NPs are composed of nanoparticles with 100–150 nm in diameter,and have a small Brunauer-Emmett-Teller surface area of 6.85 m~2/g.The formation of Zn O nanoparticles is relative to the peeling of H_2 release.Furthermore,the product has big strain-stress leading to the red-shift in the band gap of product,and shows a strong green emission centered at 515 nm revealing enough atomic defects in Zn O NPs.As a comparison with P25,the obtained dust gray Zn O NPs have a strong absorbance in the region of 200–700 nm,suggesting the wide wave-band utilization in sunlight.Based on the traits above,the Zn O NPs show excellent photocatalytic activity on the degradation of rhodamine B(Rh-B)under solar light irradiation,close to that under UV irradiation.Importantly,the Zn O NPs could be well recycled in water due to the quick sedimentation in themselves in solution.The low-cost and scalable preparation,high photocatalytic activity,and convenient recycle of Zn O NPs endow themselves with promising application in purifying wastewater.     

Photoinduced Dynamics and Toxicity of a Cancer Drug in Proximity of Inorganic Nanoparticles under Visible Light

Drug sensitization with various inorganic nanoparticles (NPs) has proved to be a promising and an emergent concept in the field of nanomedicine. Rose bengal (RB), a notable photosensitizer, triggers the formation of reactive oxygen species under green‐light irradiation, and consequently, it induces cytotoxicity and cell death. In the present study, the effect of photoinduced dynamics of RB upon complexation with semiconductor zinc oxide NPs is explored. To accomplish this, we successfully synthesized nanohybrids of RB with ZnO NPs with a particle size of 24 nm and optically characterized them. The uniform size and integrity of the particles were confirmed by high‐resolution transmission electron microscopy. UV/Vis absorption and steady‐state fluorescence studies reveal the formation of the nanohybrids. ultrafast picosecond‐resolved fluorescence studies of RB–ZnO nanohybrids demonstrate an efficient electron transfer from the photoexcited drug to the semiconductor NPs. Picosecond‐resolved Förster resonance energy transfer from ZnO NPs to RB unravel the proximity of the drug to the semiconductor at the molecular level. The photoinduced ROS formation was monitored using a dichlorofluorescin oxidation assay, which is a conventional oxidative stress indicator. It is observed that the ROS generation under green light illumination is greater at low concentrations of RB–ZnO nanohybrids compared with free RB. Substantial photodynamic activity of the nanohybrids in bacterial and fungal cell lines validated the in vitro toxicity results. Furthermore, the cytotoxic effect of the nanohybrids in HeLa cells, which was monitored by MTT assay, is also noteworthy.     

In Situ Photocatalytically Heterostructured ZnOAg Nanoparticle Composites as Effective Cathode‐Modifying Layers for Air‐Processed Polymer Solar Cells

A heterostructured semiconductor–metal ZnO?Ag nanoparticle (NP) composite was constructed through a straightforward photocatalytic strategy by using UV irradiation of ZnO NPs and an aqueous solution of Ag precursor. The ZnO?Ag NP composites serve as an effective cathode‐modifying layer in polymer solar cells (PSCs) with increased short‐circuit current density owing to the light‐trapping effect, and improved optical and electrical conductivity properties compared with pure ZnO NPs. The Ag NPs, which are photodeposited in situ on ZnO NPs, can act as effective antennas for incident light to maximize light harvesting and minimize radiative decay or nonradiative losses, consequently resulting in the enhanced photogeneration of excitons in PSCs. Systematic photoelectron and ‐physical investigations confirm that heterostructured ZnO?Ag NPs can significantly improve charge separation, transport, and collection, as well as lower charge recombination at the cathode interface, leading to a 14.0 % improvement in air‐processed device power conversion efficiency. In addition, this processable, cost‐effective, and scalable approach is compatible with roll‐to‐roll manufacturing of large‐scale PSCs.     

Green synthesis,characterization, and biological activities of saffron leaf extract-mediated zinc oxide nanoparticles: A sustainable approach to reuse an agricultural waste

To increase the profitability and sustainability of agricultural waste, a facile green approach was established to synthesize zinc oxide nanoparticles (ZnO NPs) using saffron leaf extract as a reducing and stabilizing agent. Structural characteristics of NPs were investigated by X-ray diffraction (XRD), Fourier-transform infrared (FTIR), field emission scanning electron microscopy (FESEM), and UV–Visible (UV–Vis) spectroscopy. Characterization results revealed that ZnO NPs is highly crystalline with a hexagonal wurtzite structure and spherical particles with diameter less than 50 nm, as confirmed by XRD and FESEM techniques. UV–Vis absorption spectra depicted an absorption peak at 370 nm, which confirms the formation of ZnO NPs. FTIR spectral analysis confirmed the presence of functional groups and metal oxygen groups. The biological activities of ZnO NPs were also investigated. The antibacterial effect of ZnO NPs was investigated against selected food pathogens (Salmonella Typhimurium, Listeria monocytogenes, and Enterococcus faecalis). The study results prove that the green synthesized ZnO NPs show enhanced antibacterial activity against S. Typhimurium when compared with other strains. A dose-dependent free radical scavenging activity was observed for ZnO NPs in both 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) and fluorescence recovery after photobleaching (FRAP) assays. The ZnO NPs were evaluated for their photocatalytic activity during the degradation of methylene blue (MB) dye in aqueous solutions. The maximum removal of MB achieved was 64% with an initial ZnO NP concentration of 12 mg/mL under UV light. The present study revealed that the agricultural waste (saffron leaf) provides a simple and eco-friendly option to sustainably synthesize ZnO NPs for use as a photocatalyst. In addition, this is the first report on saffron leaf-mediated synthesis of ZnO NPs.     

Toxicological effect of ZnO nanoparticles based on bacteria

Streptococcus agalactiae and Staphylococcus aureus are two pathogenetic agents of several infective diseases in humans. Biocidal effects and cellular internalization of ZnO nanoparticles (NPs) on two bacteria are reported, and ZnO NPs have a good bacteriostasis effect. ZnO NPs were synthesized in the EG aqueous system through the hydrolysis of ionic Zn2+ salts. Particle size and shape were controlled by the addition of the various surfactants. Bactericidal tests were performed in an ordinary broth medium on solid agar plates and in liquid systems with different concentrations of ZnO NPs. The biocidal action of ZnO materials was studied by transmission electron microscopy of bacteria ultrathin sections. The results confirmed that bactericidal cells were damaged after ZnO NPs contacted with them, showing both gram-negative membrane and gram-positive membrane disorganization. The surface modification of ZnO NPs causes an increase in membrane permeability and the cellular internalization of these NPs whereas there is a ZnO NP structure change inside the cells.     

Improvement in the light conversion efficiency of silicon solar cell by spin coating of CuO,ZnO nanoparticles and CuO/ZnO mixed metal nanocomposite material

Synthesis of pure Zinc oxide (ZnO), Copper oxide (CuO) nanoparticles (NPs) and their (ZnO/CuO) nanocomposites (NCs) in 1:1 M ratio were successfully prepared by co-precipitation method. The structural properties of the as synthesized nanoparticles and nanocomposite materials were investigated using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) techniques. Optical band-gap studies were done using UV–Visible absorption spectroscopy. Photovoltaic properties of pure ZnO NPs, CuO NPs and ZnO/CuO NCs coated over a single-crystalline silicon solar cell were carried out to compare improvement of light-conversion efficiency in coated solar cell. The maximum light conversion efficiencies were found to be of 8.02% for CuO (3 mg/ml concentration) and 7.28% for ZnO NPs (3 mg/ml concentration), whereas that of mixed metal nanocomposite CuO/ZnO NCs was found to be 7.62%. at very low concentration of 1 mg/ml. This indicates with low concentration of mixed metal NCs an improvement in light efficiency can be obtained. The enhancement in efficiency could be due to formation of p - n heterojunction by CuO/ZnO NCs composites which enhances the number of electrons and holes participating in conduction on the surface.     

Green synthesis of silver nanoparticles using Thymus kotschyanus extract and evaluation of their antioxidant,antibacterial and cytotoxic effects

Present study used ecofriendly, cost efficient and easy method for synthesis of silver nanoparticles (Ag NPs) at the room temperature by Thymus Kotschyanus extract as reducing and capping agent. Various analytical technique including UV–Vis absorption spectroscopy determined presence of Ag NPs in the solution, the functional groups of Thymus Kotschyanus extract in the reduction and capping process of Ag NPs are approved by FT‐IR, crystallinity with the fcc plane approved from the X‐ray diffraction (XRD) pattern, energy dispersive spectroscopy (EDS) determined existence of elements in the sample, surface morphology, diverse shapes and size of present Ag NPs were showed by using scanning electron microscopy (SEM), atomic force microscopy (AFM) and high resolution transmission electron microscopy (HRTEM). Beginning and end destroy temperature of present silver nanoparticles were determined by thermal gravimetric spectroscopy (TGA). In addition, antibacterial, antioxidant and cytotoxicity properties of Ag NPs were studied. Agar disk and agar well diffusion are the methods to determined antibacterial properties of synthesized Ag NPs. Also MIC (Minimum Inhibitory Concentration) and MBC (Minimum Bactericidal Concentration) were recognized by macro broth dilution assay. DPPH free radical scavenging assay was used for antioxidant property and compare to butylated hydroxytoluene (BHT) as standard antioxidant that showed high antioxidant activity more than BHT. Synthesized Ag NPs have great cell viability in a dose depended manner and demonstrate that this method for synthesis silver nanoparticles provided nontoxic. The average diameter of synthesized Ag NPs was about 50–60 nm.     

Efficient photodegradation of methyl orange and bactericidal activity of Ag doped ZnO nanoparticles

In the present work, silver-doped ZnO (Ag–ZnO NPs) with different concentrations of silver ions (0.3, 0.5, 1.0 and 1.5 mol %) were synthesized by using a simple co-precipitation method. The Ag–ZnO NPs were primarily characterized by XRD, FT-IR, SEM, EDS, TEM, UV–Vis. DRS, PL and BET surface area. The XRD analysis of Ag–ZnO NPs shows a wurtzite structure and optimized Ag–ZnO NPs (1.0 mol %) exhibit a lower crystallite size of 15.96 nm than that of bare ZnO (19.07 nm). Optical study shows a decrease in band gap from 3.13 to 2.97 eV as the concentration of Ag ions increases from 0.3 to 1.5 mol%. TEM images reveal the spherical shape particle with sizes ranging between 10 and 15 nm. From the multipoint BET plot, the surface area of Ag–ZnO NPs found 38.06 m²/gwhich is higher than the ZnO NPs (34.48 m²/g). The photocatalytic study demonstrated that the Ag–ZnO NPs (1.0 mol %) has an excellent photodegradation efficiency of Methyl Orange (96.74%)with a 26% increment as compared to bare ZnO (70.47%). Furthermore, the bactericidal activity of Ag–ZnO NPs (1.0 mol %) was investigated against four different bacterial strains. The results explored that the Gram-negative bacteria (E. coli and P. vulgaris) are more sensitive than Gram-positive (S. aureus and B. cereus) to Ag–ZnO NPs. Overall, the anticipated material is economical and reusable for photodegradation and antibacterial activity.     

Green biosynthesis and characterization of zinc oxide nanoparticles using Corymbia citriodora leaf extract and their photocatalytic activity

ABSTRACT

We reported a green and simple method for biosynthesizing zinc oxide nanoparticles (ZnO NPs) using Corymbia citriodora leaf extract as reducing and stabilizing agent. SEM, EDX, XRD, UV–VIS spectroscopy, Raman spectroscopy and TGA have been used for characterizing the biosynthesized ZnO NPs. The results indicating the ZnO NPs synthesized by C. citriodora leaf extract have high purity and the average size is 64?nm. The photocatalytic activity of the ZnO NPs has been investigated by degradation methylene blue under visible light irradiation. Due to the smaller size, the biosynthesized ZnO NPs showed an excellent photocatalytic performance.     

Calcination temperature-dependent morphology of photocatalytic ZnO nanoparticles prepared by an electrochemical–thermal method

ZnO nanoparticles (NPs) with tunable morphologies were synthesized by a hybrid electrochemical–thermal method at different calcination temperatures without the use of any surfactant or template. The NPs were characterized by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction, dynamic light scattering, thermogravimetry–differential thermal analysis, scanning electron microscope and N₂ gas adsorption–desorption studies. The FT-IR spectra of ZnO NPs showed a band at 450 cm^?1, a characteristic of ZnO, which remained fairly unchanged at calcination temperatures even above 300 °C, indicating complete conversion of the precursor to ZnO. The products were thermally stable above 300 °C. The ZnO NPs were present in a hexagonal wurtzite phase and the crystallinity of ZnO increased with an increasing calcination temperature. The ZnO NPs calcined at lower temperature were mesoporous in nature. The surface areas of ZnO NPs calcined at 300 and 400 °C were 51.10 and 40.60 m² g^?1, respectively, which are significantly larger than commercial ZnO nanopowder. Surface diffusion has been found to be the key mechanism of sintering during heating from 300 to 700 °C with the activation energy of sintering as 8.33 kJ mol^?1. The photocatalytic activity of ZnO NPs calcined at different temperatures evaluated by photocatalytic degradation of methylene blue under sunlight showed strong dependence on the surface area of ZnO NPs. The ZnO NPs with high surface area showed enhanced photocatalytic activity.     

Experimental and Theoretical Study of Enhanced Photocatalytic Activity of Mg‐Doped ZnO NPs and ZnO/rGO Nanocomposites

A systematic experimental and theoretical study of the origin of the enhanced photocatalytic performance of Mg‐doped ZnO nanoparticles (NPs) and Mg‐doped ZnO/reduced graphene oxide (rGO) nanocomposites has been performed. In addition to Mg, Cd was chosen as a doping material for the bandgap engineering of ZnO NPs, and its effects were compared with that of Mg in the photocatalytic performance of ZnO nanostructures. The experimental results revealed that Mg, as a doping material, recognizably ameliorates the photocatalytic performance of ZnO NPs and ZnO/graphene nanocomposites. Transmission electron microscopy (TEM) images showed that the Mg‐doped and Cd‐doped ZnO NPs had the same size. The optical properties of the samples indicated that Cd narrowed the bandgap, whereas Mg widened the bandgap of the ZnO NPs and the oxygen vacancy concentration was similar for both samples. Based on the experimental results, the narrowing of the bandgap, the particle size, and the oxygen vacancy did not enhance the photocatalytic performance. However, Brunauer–Emmett–Teller (BET) and Barret–Joyner–Halenda (BJH) models showed that Mg caused increased textural properties of the samples, whereas rGO played an opposite role. A theoretical study, conducted by using DFT methods, showed that the improvement in the photocatalytic performance of Mg‐doped ZnO NPs was due to a higher electron transfer from the Mg‐doped ZnO NPs to the dye molecules compared with pristine ZnO and Cd‐doped ZnO NPs. Moreover, according to the experimental results, along with Mg, graphene also played an important role in the photocatalytic performance of ZnO.     

Synthesis,physico-chemical characterization,antimicrobial activity and toxicological features of AgZnO nanoparticles

Silver-zinc oxide nanoparticles (AgZnO NPs) were chemically synthesized by the deposition of Ag NPs on the surface of ZnO NPs using silver nitrate, three types of anionic polyelectrolytes and citric acid as reagents. The Wavelength Dispersive X-ray Fluorescence (WDXRF) spectrometry of AgZnO NPs revealed 0.41–0.69 wt% Ag, and balance ZnO. The existence of Ag NPs on the surface of ZnO NPs with hexagonal wurtzite structure was highlighted by X-ray Diffraction (XRD) analysis, scanning electron microscopy (SEM), and Ultraviolet–Visible (UV–Vis) spectroscopy. The diffuse reflectance absorption of AgZnO NPs in the visible light region increased with the increase of Ag NPs content. The Fourier Transform Infrared (FTIR) spectrometry revealed no chemical bonding between Ag NPs and ZnO NPs and confirmed the presence of functional groups characteristic to ZnO and carboxylic acid salts. The newly synthesized AgZnO NPs displayed antimicrobial activity against all the tested medically relevant pathogens, with minimal (biofilm) inhibitory concentrations ranging from 1.875 mg/mL to 7.5 mg/mL. Although the in vitro genotoxicity assay revealed a relatively high micronuclei index, the in vivo micronucleus (MN) test revealed a low MN frequency in animals treated with AgZnO NPs. The histopathological analysis revealed non-significant structural changes of the hepatic parenchyma, renal cortex and intestinal mucosa and minimal inflammatory reactions. The AgZnO NPs administration induced TUNEL positive nuclei of Kupffer cells in the liver parenchyma. The present study shows that the newly synthesized AgZnO NPs are active against planktonic and adherent microorganisms and could be exploited to develop novel antimicrobial strategies for the biotechnology and biomedical fields. Easy scalability of the developed chemical synthesis is a major advantage in producing large batches of AgZnO NPs with reproducible properties.     

Investigating morphological and performance deterioration of injection-molded rice husk–polypropylene composites due to various liquid uptakes

Systematic investigations for the tensile strengths, tensile moduli, flexural strengths, flexural moduli, and impact strengths of various reinforced conditions of rice husk–polypropylene composites under the effect of different liquids uptakes were carried out. Three different liquids, i.e., lubricant oil, sea water, and distilled water, were utilized in this work to investigate their effects on the composites’ mechanical performance. Moreover, morphological analysis of the designed composites was also carried out. Various fiber loadings at 35, 40, 45, 50, and 55 wt% have been designed and investigated. The rice husk–polypropylene composites have been prepared by injection molding, and struktol was used as an additive. The composites were immersed in three different liquids—lubricant oil, sea water, and distilled water—for 4 weeks. The water uptake of rice husk–polypropylene composites for distilled water was the highest compared to lubricant oil and sea water. Moreover, results have demonstrated that mechanical properties of composites immersed in sea water were the best, followed by those immersed in lubricant oil, and then those immersed in distilled water. In addition, it was observed that more voids and pull-out existed in composites immersed in lubricant oil, followed by those immersed in distilled water, and then those immersed in sea water. Tensile moduli showed a reduction trend for all composites with increasing filler loading. However, flexural moduli improved as the filler loading increased. Also, results here demonstrated an optimum filler loading condition for each particular mechanical property of rice husk–polypropylene composites.     

Facile synthesis of Pd-decorated ZnO nanoparticles for acetone sensors with enhanced performance

ZnO and Pd nanoparticles (NPs) with average diameter of 38 and 10 nm were prepared in advance through a chemical solution method. Pd-functionalized ZnO nanoparticles (Pd@ZnO) were simply synthesized by adding ethanol solution of Pd NPs into ZnO powder, and annealing in argon atmosphere at 500 °C for 1 h after grinding for 30 min. The morphology and structure of the materials were systemically analyzed using Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) techniques. A weak peak in the XRD pattern of Pd@ZnO belonging to the (111) plane of elemental Pd indicated successfully loading of Pd. EDS and TEM results further confirmed successfully coating of Pd NPs onto the surface of ZnO. Sensors using ZnO NPs decorated with Pd (1 wt%) on the surface of exhibited highly elevated sensitivity of 76 in comparing with the response of 36 when based on pure ZnO NPs. In addition, such modification also resulted in a decrease in the operating temperature from 370 to 340 °C for 100 ppm acetone vapor. The sensing mechanism of the sensor based on Pd@ZnO NPs is discussed. Addition of Pd NPs can play an important role in improving the performance of gas sensors, including high sensitivity, good selectivity, and short response/recovery times.     

Modification in structural,optical, morphological,and electrical properties of zinc oxide (ZnO) nanoparticles (NPs) by metal (Ni,Co) dopants for electronic device applications

In the present work, Zinc Oxide (ZnO) nanoparticles (NPs) were synthesized by the chemical co-precipitation method using Zinc Chloride as the initial chemical, while Nickel and Cobalt chloride as dopants. Phase identification of metal (Ni, Co) doped Zinc Oxide nanoparticles (NPs) was observed using x-ray diffraction (XRD). The small lattice distortion or phase changes appeared due to shifting of diffraction angles peaks towards larger angle in ZnO are corresponded to metal (Ni, Co) dopant. The average crystallite size appears to decrement in NP size from 7.67 nm to 6.52 nm and 5.35 nm to 5.17 nm with increasing 5 % to 80 % of metal (Ni, Co) dopant respectively. The optical characteristics, including the absorption spectra of the prepared sample were observed through UV–Vis spectroscopy, Meanwhile SEM confirmed the observation of composition change in specimen with metal (Ni, Co) dopant concentration. The bandgap value was also found decrement 5.23 eV to 5.05 eV with increment of metal (Ni, Co) dopant concentration. The functional groups were measured by Fourier transformation infrared spectroscopy (FTIR). FTIR peaks found the metal (Ni, Co) doped ZnO with the vibration mode of (Zn²⁺ –O^2?) ions due to the increment of dopant concentrations. Furthermore, electrical results show the ohmic behavior of prepared samples. These findings indicate the possibility of tuning optical, structural and electrical properties of metal (Ni, Co) doped ZnO with various dopant concentrations of Nickel and will have great potential to find application in optoelectronic devices.     

Green Synthesized ZnO Nanoparticles as Biodiesel Blends and Their Effect on the Performance and Emission of Greenhouse Gases

Pollution and global warming are a few of the many reasons for environmental problems, due to industrial wastes and greenhouse gases, hence there are efforts to bring down such emissions to reduce pollution and combat global warming. In the present study, zinc oxide nanoparticles are green synthesized using cow dung as fuel, through combustion. Synthesized material was characterized by FTIR, XRD, UV, and FESEM. The as-prepared ZnO-GS NPs were employed as a transesterification catalyst for the preparation of biodiesel from discarded cooking oil. The biodiesel obtained is termed D-COME (discarded cooking oil methyl ester), which is blended with 20% commercial diesel (B20). Additionally, this blend, i.e., B20, is further blended with varying amounts of as-prepared ZnO-GS NPs, in order to ascertain its effects on the quality of emissions of various greenhouse gases such as hydrocarbons, CO_x, NO_x. Moreover, the brake thermal efficiency (BTHE) and brake specific fuel consumption (BSFC) were studied for their blends. The blend (B20) with 30 mg of ZnO-GS, i.e., B20-30, displays the best performance and reduced emissions. Comparative studies revealed that the ZnO-GS NPs are as efficient as the ZnO-C NPs, indicating that the green synthetic approach employed does not affect the efficiency of the ZnO NPs.     

Magnesium and Zinc Oxide Nanoparticles from Datura alba Improve Cognitive Impairment and Blood Brain Barrier Leakage

Epilepsy is a neurological disorder involving persistent spontaneous seizures and uncontrolled neuronal excitability that leads to cognitive impairments and blood–brain barrier (BBB) disruption. Currently available antiepileptic drugs present side effects and researchers are trying to discover new agents with properties to overcome these drawbacks. The aim was to synthesize magnesium oxide (MgO) and zinc oxide (ZnO) nanoparticles from Datura alba fresh leaf extracts and evaluate their anti-epileptic potential in mice kindling or a repetitive seizures model. The phytoassisted synthesized nanoparticles were characterized using spectroscopy; FT-IR, XRD, SEM, and EDX. Analysis of the NPs confirmed the crystalline pleomorphic shape using the salts of both zinc and magnesium possibly stabilized, functionalized and reduced by bioactive molecules present in plant extract. By using several characterization techniques, NPs were confirmed. UV-Vis spectroscopy of biologically produced ZnO and MgO revealed distinctive peaks at 380 nm and 242 nm, respectively. Our findings categorically demonstrated the reductive role of biomolecules in the formation of ZnO and MgO NPs. The mice kindling model was induced using seven injections of Pentylenetetrazole (PTZ, 40 mg/kg, i.p) for 15 days alternatively. The results showed that mice post-treated with either ZnO or MgO nanoparticles (10 mg/kg, i.p) significantly improved in respect of behavior and memory as confirmed in the Morris water maze (MWM), open field (OF), novel object recognition (NOR) test compared with PTZ treated mice. Furthermore, the ZnO and MgO nanoparticle treatment also maintained the integrity of the BBB, reducing the leakage, as confirmed by Evans blue dye (EBD) compared with PTZ treated mice only. In summary, the current finding demonstrates that green synthesized ZnO and MgO nanoparticles have neuroprotective, ant-epileptic potential, molecular mechanisms, and clinical implications need to be further explored.     

Zinc and copper oxide nanoparticles decrease synaptosomal glutamate uptake: an in vitro study

Nanoparticles (NPs) are considered as an important environmental risk factor for cognitive impairments and neurodegenerative disorders. Recent evidences have reported a glutamatergic system response against air-borne NPs. Zinc and copper oxides (ZnO and CuO) NPs are the most common metal oxide NPs in industries. The effects of these NPs on hippocampal voltage-dependent ion channels and spatial cognition have been previously studied. However, there is a lack of evidence regarding the effects of ZnO and CuO NPs on glutamatergic synapse neurotransmission in central nervous system. In the present study, the effects of ZnO and CuO NPs on glutamate (Glu) release and uptake have been investigated in isolated nerve terminals (synaptosomes). Our findings have shown that, even in high doses of ZnO and CuO NPs, no significant effect on Glu release is observed. However, a decrease has been observed in uptake of Glu. Hence, ZnO and CuO NPs can be considered as hazardous agents inducing neurodegenerative disorders through Glu excitotoxicity.     

Modification of poly(benzimidazole‐amide) nanocomposites by the incorporation of amine‐functionalized ZnO nanoparticles: Thermal and morphological characterization

Fabrication, characterization, and properties of novel poly(benzimidazole‐amide)/functionalized ZnO nanocomposites (PBIA/APS‐ZnO NCs) were investigated. At first, an aromatic PBA containing 3 imidazole units per repeat unit was synthesized by direct polycondensation of 1,3‐bis(5‐carboxylic acid‐2‐benzimidazole)benzene (BCAB) with 5‐(2‐benzimidazole)‐1,3‐phenylenediamine (DAMI) with good yield as a polymeric matrix. The periphery of zinc oxide nanoparticles (ZnO NPs) was modified with 3‐aminopropyltriethoxysilane (APS) to have a better dispersion NPs and enhancing interactions between nanoparticles and PBIA matrix. Different percentages of functionalized NPs (0, 4, 8, and 12 wt.%) were then embedded in PBA matrix through ultrasonic irradiation technique. Fourier transform infrared and thermo‐gravimetric analysis (TGA) confirmed that APS was successfully attached on the ZnO NP surface. The obtained NCs were characterized by means of Fourier transform infrared, X‐ray diffraction, scanning electron microscopy, and TGA. The TGA of the PBIA/APS‐ZnO NCs showed the enhancement in the thermal stability in comparison with the neat PBIA and that this increase is higher when the NP content increases. Scanning electron microscopy analyses of NCs revealed that the dispersion of APS‐ZnO NPs was uniformly done in the PBIA matrix.     

Sonochemical Coatings of ZnO and CuO Nanoparticles Inhibit Streptococcus mutans Biofilm Formation on Teeth Model

Antibiotic resistance has prompted the search for new agents that can inhibit bacterial growth. We recently reported on the antibiofilm activities of nanosized ZnO and CuO nanoparticles (NPs) synthesized by using sonochemical irradiation. In this study, we examined the antibacterial activity of ZnO and CuO NPs in a powder form and also examined the antibiofilm behavior of teeth surfaces that were coated with ZnO and CuO NPs using sonochemistry. Free ZnO and CuO NPs inhibited biofilm formation of Streptococcus mutans . Furthermore, by using the sonochemical procedure, we were able to coat teeth surfaces that inhibited bacterial colonization.