Search Results (13)

In animal production, nanoparticulate zinc oxide exhibits synergistic antibacterial efficacy coupled with growth-promoting effects, positioning itself as a novel antibiotic alternative with enhanced biosafety profiles. However, its dose-dependent toxicity poses challenges. Objective: The experimental design sought to quantify the protective effects of dietary rutin against zinc-overload-induced damage. Methods: A zinc-overload murine model was established by giving high-dose ZnO nanoparticles (HZn, 5000 mg/kg/day) for 21 days. Mice were then fed rutin at doses of 300, 600, or 1200 mg/kg. Body weight, relative organ indexes, zinc concentrations, serum enzyme activities, and tissue-level indicators of apoptosis, autophagy, mitochondrial function, and antioxidant capacity were measured. Results: The results showed that rutin could not reverse HZn-induced body weight decline but improved relative organ indexes in liver and kidney. It alleviated HZn-induced cell damage and enhanced antioxidant capacity in jejunum and serum through Nrf2 activation, without inhibiting HZn-induced zinc elevation. Conclusions: Rutin, especially at 600 mg/kg, can partially restore hepatic function and organ index and mitigate HZn-induced hepatic and jejunal injuries. Full article

Zinc oxide nanoparticles (ZnO NPs) are one of the most widely used nanoparticulate materials due to their antimicrobial properties. However, the current use of ZnO NPs is hindered by their potential cytotoxicity concerns, which are likely attributed to the generation of reactive oxygen species (ROS) and the dissolution of particles to ionic zinc. To reduce the cytotoxicity of ZnO NPs, transitional metals are introduced into ZnO lattices to modulate the ROS production and NP dissolution. However, the influence of the doping element, doping concentration, and particle size on the cytotoxicity and antimicrobial properties remains unexplored. This study presents a comprehensive investigation of a library of doped ZnO NPs to elucidate the relationship between their physicochemical properties, antimicrobial activity against Escherichia coli (E. coli), and cytotoxicity to mammalian cells. The library comprises 30 variants, incorporating three different dopant metals—iron, manganese, and cobalt—at concentrations of 0.25%, 1%, and 2%, and calcined at three temperatures (350 °C, 500 °C, and 600 °C), resulting in varied particle sizes. These ZnO NPs were prepared by low temperature co-precipitation followed by high-temperature calcination. Our results reveal that the choice of dopant elements significantly influences both antimicrobial efficacy and cytotoxicity, while dopant concentration and particle size have comparatively minor effects. High-throughput UV–visible spectroscopic analysis identified Mn- and Co-doped ZnO NPs as highly effective against E. coli under standard conditions. Compared with undoped ZnO particles, Mn- and Co-doping significantly increased the oxidative stress, and the Zn ion release from NPs was increased by Mn doping and reduced by Fe doping. The combined effects of these factors increased the cytotoxicity of Mn-doped ZnO particles. As a result, Co-doped ZnO particles, especially those with 2 wt.% doping, exhibited the most favourable balance between enhanced antibacterial activity and minimized cytotoxicity, making them promising candidates for antimicrobial applications. Full article

In recent years, the morphology control of semiconductor nanomaterials has been attracting increasing attention toward maximizing their functional properties and reaching their end use in real-world devices. However, the development of easy and cost-effective methods for preparing large-scale patterned semiconductor structures on flexible temperature-sensitive substrates remains ever in demand. In this study, vapor post-treatment (VPT) is investigated as a potential, simple and low-cost post-preparative method to morphologically modify gravure-printed zinc oxide (ZnO) nanoparticulate thin films at low temperatures. Exposing nanoparticles (NPs) to acidic vapor solution, spontaneous restructuring pathways are observed as a consequence of NPs tending to reduce their high interfacial energy. Depending on the imposed environmental conditions during the treatment (e.g., temperature, vapor composition), various ZnO thin-film morphologies are produced, from dense to porous ones, as a result of the activation and interplay of different spontaneous interface elimination mechanisms, including dissolution–precipitation, grain boundary migration and grain rotation–coalescence. The influence of VPT on structural/optical properties has been examined via XRD, UV–visible and photoluminescence measurements. Controlling NP junctions and network nanoporosity, VPT appears as promising cost-effective, low-temperature and pressureless post-preparative platform for preparing supported ZnO NP-based films with improved connectivity and mechanical stability, favoring their practical use and integration in flexible devices. Full article

This study explores the challenge of antimicrobial resistance by investigating the utilization of zinc oxide (ZnO) and copper oxide (Cu₂O) nanoparticles (NPs) to combat antibiotic-resistant bacteria in wastewater treatment plants (WWTPs). The synthesized metal oxide NPs underwent thorough characterization through various analytical techniques, confirming their nanoparticulate nature. Electronic absorption and X-ray diffraction (XRD) analyses revealed successful reduction processes and crystalline properties, respectively. Fourier transform infrared spectroscopy (FTIR) results indicated the stabilization of nanoparticles in solution. Scanning electron microscopy (SEM) observations revealed well-defined spherical and flower-like morphologies for the zinc and copper oxide nanoparticles, with sizes approximately ranging from 50 nm to 25 nm Notably, the synthesized nanoparticles exhibited heightened efficacy in impeding biofilm formation, with zinc oxide NPs displaying superior antibacterial activity compared to copper. These findings suggest the promising potential of these nanoparticles in controlling antibiotic-resistant organisms, even following WWTP treatment processes. This research contributes to the ongoing advancements in nanotechnology aimed at combating antibiotic resistance, offering new prospects for the development of effective wastewater treatment strategies. Full article

Previous research using the model soil nematode Caenorhabditis elegans has revealed that silver nanoparticles (AgNP) and their transformed counterpart, sulfidized AgNP (sAgNP), reduce their reproduction and survival. To expand our understanding of the environmental consequences of released NP, we examined the synergistic/antagonistic effects of AgNP and sAgNP along with AgNO₃ (ionic control) on C. elegans infected with the pathogen Klebsiella pneumoniae. Individual exposures to each stressor significantly decreased nematode reproduction compared to controls. Combined exposures to equitoxic EC₃₀ concentrations of two stressors, Ag in nanoparticulate (AgNP or sAgNP) or ionic form and the pathogen K. pneumoniae, showed a decline in the reproduction that was not significantly different compared to individual exposures of each of the stressors. The lack of enhanced toxicity after simultaneous combined exposure is partially due to Ag decreasing K. pneumoniae pathogenicity by inhibiting biofilm production outside the nematode and significantly reducing viable pathogens inside the host. Taken together, our results indicate that by hindering the ability of K. pneumoniae to colonize the nematode’s intestine, Ag reduces K. pneumoniae pathogenicity regardless of Ag form. These results differ from our previous research where simultaneous exposure to zinc oxide (ZnO) NP and K. pneumoniae led to a reproduction level that was not significantly different from the controls. Full article

We report here the successful shape-controlled synthesis of dielectric spinel-type ZnCr₂O₄ nanoparticles by using a simple sol-gel auto-combustion method followed by successive heat treatment steps of the resulting powders at temperatures from 500 to 900 °C and from 5 to 11 h, in air. A systematic study of the dependence of the morphology of the nanoparticles on the annealing time and temperature was performed by using field effect scanning electron microscopy (FE-SEM), powder X-ray diffraction (PXRD) and structure refinement by the Rietveld method, dynamic lattice analysis and broadband dielectric spectrometry, respectively. It was observed for the first time that when the aerobic post-synthesis heat treatment temperature increases progressively from 500 to 900 °C, the ZnCr₂O₄ nanoparticles: (i) increase in size from 10 to 350 nm and (ii) develop well-defined facets, changing their shape from shapeless to truncated octahedrons and eventually pseudo-octahedra. The samples were found to exhibit high dielectric constant values and low dielectric losses with the best dielectric performance characteristics displayed by the 350 nm pseudo-octahedral nanoparticles whose permittivity reaches a value of ε = 1500 and a dielectric loss tan δ = 5 × 10⁻⁴ at a frequency of 1 Hz. Nanoparticulate ZnCr₂O₄-based thin films with a thickness varying from 0.5 to 2 μm were fabricated by the drop-casting method and subsequently incorporated into planar capacitors whose dielectric performance was characterized. This study undoubtedly shows that the dielectric properties of nanostructured zinc chromite powders can be engineered by the rational control of their morphology upon the variation of the post-synthesis heat treatment process. Full article

One of the emerging and environmentally friendly technologies is the photoelectrochemical generation of green hydrogen; however, the cheap cost of production and the need for customizing photoelectrode properties are thought to be the main obstacles to the widespread adoption of this technology. The primary players in hydrogen production by photoelectrochemical (PEC) water splitting, which is becoming more common on a worldwide basis, are solar renewable energy and widely available metal oxide based PEC electrodes. This study attempts to prepare nanoparticulate and nanorod-arrayed films to better understand how nanomorphology can impact structural, optical, and PEC hydrogen production efficiency, as well as electrode stability. Chemical bath deposition (CBD) and spray pyrolysis are used to create ZnO nanostructured photoelectrodes. Various characterization methods are used to investigate morphologies, structures, elemental analysis, and optical characteristics. The crystallite size of the wurtzite hexagonal nanorod arrayed film was 100.8 nm for the (002) orientation, while the crystallite size of nanoparticulate ZnO was 42.1 nm for the favored (101) orientation. The lowest dislocation values for (101) nanoparticulate orientation and (002) nanorod orientation are 5.6 × 10⁻⁴ and 1.0 × 10⁻⁴ dislocation/nm², respectively. By changing the surface morphology from nanoparticulate to hexagonal nanorod arrangement, the band gap is decreased to 2.99 eV. Under white and monochromatic light irradiation, the PEC generation of H₂ is investigated using the proposed photoelectrodes. The solar-to-hydrogen conversion rate of ZnO nanorod-arrayed electrodes was 3.72% and 3.12%, respectively, under 390 and 405 nm monochromatic light, which is higher than previously reported values for other ZnO nanostructures. The output H₂ generation rates for white light and 390 nm monochromatic illuminations were 28.43 and 26.11 mmol.h⁻¹cm⁻², respectively. The nanorod-arrayed photoelectrode retains 96.6% of its original photocurrent after 10 reusability cycles, compared to 87.4% for the nanoparticulate ZnO photoelectrode. The computation of conversion efficiencies, H₂ output rates, Tafel slope, and corrosion current, as well as the application of low-cost design methods for the photoelectrodes, show how the nanorod-arrayed morphology offers low-cost, high-quality PEC performance and durability. Full article

In this study, a nanocomposite of cerium oxide-zinc (CeO₂-Zn; 26 ± 11 nm) based on the antioxidant rare-earth cerium oxide (CeO₂) nanoparticles (NPs) with the modifier zinc (Zn) was synthesized by sintering method and characterized. Its bio-response was examined in human umbilical-vein-derived endothelial (HUVE) cells to get insight into the components of vascular system. While NPs of CeO₂ did not significantly alter cell viability up to a concentration of 200 µg/mL for a 24 h exposure, 154 ± 6 µg/mL of nanocomposite CeO₂-Zn induced 50% cytotoxicity. Mechanism of cytotoxicity occurring due to nanocomposite by its Zn content was compared by choosing NPs of ZnO, possibly the closest nanoparticulate form of Zn. ZnO NPs lead to the induction of higher reactive oxygen species (ROS) (DCF-fluorescence), steeper depletion in antioxidant glutathione (GSH) and a greater loss of mitochondrial membrane potential (MMP) as compared to that induced by CeO₂-Zn nanocomposite. Nanocomposite of CeO₂-Zn, on the other hand, lead to significant higher induction of superoxide radical (O₂^•−, DHE fluorescence), nitric oxide (NO, determined by DAR-2 imaging and Griess reagent) and autophagic vesicles (determined by Lysotracker and monodansylcadeverine probes) as compared to that caused by ZnO NP treatment. Moreover, analysis after triple staining (by annexin V-FITC, PI, and Hoechst) conducted at their respective IC50s revealed an apoptosis mode of cell death due to ZnO NPs, whereas CeO₂-Zn nanocomposite induced a mechanism of cell death that was significantly different from apoptosis. Our findings on advanced biomarkers such as autophagy and mode of cell death suggested the CeO₂-Zn nanocomposite might behave as independent nanostructure from its constituent ones. Since nanocomposites can behave independently of their constituent NPs/elements, by creating nanocomposites, NP versatility can be increased manifold by just manipulating existing NPs. Moreover, data in this study can furnish early mechanistic insight about the potential damage that could occur in the integrity of vascular systems. Full article

The need to increase crop productivity and resistance directs interest in nanotechnology. Indeed, biogenic metal oxide nanoparticles can promote beneficial effects in plants, while their synthesis avoids the environmental impacts of conventional synthetic procedures. In this context, this research aimed to synthesize biogenic zinc oxide nanoparticles (ZnO-NPs) using, for the first time, an extract of a wild and spontaneous aquatic species, Lemna minor (duckweed). The effectiveness of this biogenic synthesis was evidenced for comparison with non-biogenic ZnO-NPs (obtained without using the plant extract), which have been synthesized in this research. XRD (X-ray diffraction), FE-SEM (field emission gun electron scanning microscopy), EDX (energy dispersive x-ray spectroscopy), TEM (transmission electron microscope) and UV-vis (ultraviolet-visible spectrophotometry) showed the biogenic approach effectiveness. The duckweed extract was subjected to UHPLC-ESI/QTOF-MS (ultra high-pressure liquid chromatography quadrupole time of flight mass spectrometry) phenolic profiling. This untargeted characterization highlighted a high and chemically diverse content in the duckweed extract of compounds potentially implicated in nanoparticulation. From an application standpoint, the effect of biogenic nanoparticles was investigated on some traits of maize subjected to seed priming with a wide range of biogenic ZnO-NPs concentrations. Inductive effects on the shoot and root biomass development were ascertained concerning the applied dosage. Furthermore, the biogenic ZnO-NPs stimulated the content of chlorophylls, carotenoids, and anthocyanin. Finally, the study of malondialdehyde content (MDA) as a marker of the oxidative status further highlighted the beneficial and positive action of the biogenic ZnO-NPs on maize. Full article

Cerium dioxide nanoparticles are pollutants of emerging concern. They are rarely immobilized in the environment. This study extends our work on Pisum sativum L. as a model plant, cultivated worldwide, and is well suited for investigating additive interactions induced by nanoceria. Hydroponic cultivation, which prompts accurate plant growth control and three levels of CeO₂ supplementation, were applied, namely, 100, 200, and 500 mg (Ce)/L. Phytotoxicity was estimated by fresh weights and photosynthesis parameters. Additionally, Ce, Cu, Zn, Mn, Fe, Ca, and Mg contents were analyzed by high-resolution continuum source atomic absorption and inductively coupled plasma optical emission techniques. Analysis of variance has proved that CeO₂ nanoparticles affected metals uptake. In the roots, it decreased for Cu, Zn, Mn, Fe, and Mg, while a reversed process was observed for Ca. The latter is absorbed more intensively, but translocation to above-ground parts is hampered. At the same time, nanoparticulate CeO₂ reduced Cu, Zn, Mn, Fe, and Ca accumulation in pea shoots. The lowest Ce concentration boosted the photosynthesis rate, while the remaining treatments did not induce significant changes. Plant growth stimulation was observed only for the 100 mg/L. To our knowledge, this is the first study that demonstrates the effect of nanoceria on photosynthesis-related parameters in peas. Full article

For water sterilization, a highly effective system utilizing electrophoresis and the antimicrobial properties of Ag/ZnO nanomaterials has been developed. However, the key component of this system, a sterilization carbon cloth containing Ag/ZnO nanomaterials, has not been evaluated with respect to the potential environmental and human health risks associated with the nanomaterials released. In this paper, a recirculation flow system and methodology were developed to study the release of Ag and ZnO during water treatment. Our study showed that the released silver nanoparticles and dissolved Ag from the carbon cloth were 50 µg/L and 143 µg/L in the United States Environmental Protection Agency (EPA) medium, respectively. The release of dissolved Zn in the EPA medium was 33 µg /L. The results indicate that the release of dissolved and nanoparticulate silver from the sterilization carbon cloth exceeded acceptable risk levels in the aquatic environment. However, if the sterilization carbon cloth was pre-washed two days prior to use, the concentration of Ag was below the drinking water limit of 0.1 mg/L. Our study provides important exposure data for a novel water sanitation technology for real-world application in waste water and drinking water treatment, and aid in assuring its safe use. Full article

In this work, we study the effect of nanostructured octahedral SnO₂ added with a binary mixture p-type and n-type metal oxide semiconductors of CuO and ZnO, on CO detection at two concentrations (100 ppm and 1000 ppm). These metal oxides (SnO₂ and binary mixture of CuO_75%/ZnO_25%) are prepared in the form of a serigraphy paste and deposited on an optimized silicon micro-hotplate. The sensors can be operated at temperature of 550 °C with a low energy consumption of only 55 mW. The binary and ternary mixtures of metal oxide are operated at different working temperature to optimize their sensitivity to CO. Full article

ZnO nanoparticles were produced by flame spray pyrolysis using zinc naphthenate as a precursor dissolved in toluene/acetonitrile (80/20 vol%). The particles properties were analyzed by XRD, BET. The ZnO particle size and morphology was observed by SEM and HR-TEM revealing spheroidal, hexagonal, and rod-like morphologies. The crystallite sizes of ZnO spheroidal and hexagonal particles ranged from 10-20 nm. ZnO nanorods were ranged from 10-20 nm in width and 20-50 nm in length. Sensing films were produced by mixing the nanoparticles into an organic paste composed of terpineol and ethyl cellulose as a vehicle binder. The paste was doctor-bladed onto Al2O3 substrates interdigitated with Au electrodes. The morphology of the sensing films was analyzed by optical microscopy and SEM analysis. Cracking of the sensing films during annealing process was improved by varying the heating conditions. The gas sensing of ethanol (25-250 ppm) was studied at 400 °C in dry air containing SiC as the fluidized particles. The oxidation of ethanol on the surface of the semiconductor was confirmed by mass spectroscopy (MS). The effect of micro-cracks was quantitatively accounted for as a provider of extra exposed edges. The sensitivity decreased notably with increasing crack of sensing films. It can be observed that crack widths were reduced with decreasing heating rates. Crack-free of thick (5 μm) ZnO films evidently showed higher sensor signal and faster response times (within seconds) than cracked sensor. The sensor signal increased and the response time decreased with increasing ethanol concentration. Full article