Alleviated cadmium toxicity in wheat (Triticum aestivum L.) by the coactive role of zinc oxide nanoparticles and plant growth promoting rhizobacteria on TaEIL1 gene expression, biochemical and physiological changes.

Cadmium (Cd) contamination in agricultural soil is a major global concern among the multitude of human health and food security. Zinc oxide nanoparticles (ZnO-NPs) and plant growth promoting rhizobacteria (PGPR) have been known to combat heavy metal toxicity in crops. Herein, the study intended to explore the interactive effect of treatments mediated by inoculation of PGPR and foliar applied ZnO-NPs to alleviate Cd induced phytotoxicity in wheat plants which is rarely investigated. For this purpose, TaEIL1 expression, morpho-physiological, and biochemical traits of wheat were examined. Our results revealed that Cd reduced growth and biomass, disrupted plant physiological and biochemical traits, and further expression patterns of TaEIL1. The foliar application of ZnO-NPs improved growth attributes, photosynthetic pigments, and gas exchange parameters in a dose-additive manner, and this effect was further amplified with a combination of PGPR. The combined application of ZnO-NPs (100 mg L-1) with PGPR considerably increased the catalase (CAT; 52.4%), peroxidase (POD; 57.4%), superoxide dismutase (SOD; 60.1%), ascorbate peroxidase (APX; 47.4%), leading to decreased malondialdehyde (MDA; 47.4%), hydrogen peroxide (H2O2; 38.2%) and electrolyte leakage (EL; 47.3%) under high Cd (20 mg kg-1) stress. Furthermore, results revealed a significant reduction in roots (56.3%), shoots (49.4%), and grains (59.4%) Cd concentration after the Combined treatment of ZnO-NPs and PGPR as compared to the control. Relative expression of TaEIL1 (two homologues) was evaluated under control (Cd 0), Cd, ZnO-NPs, PGPR, and combined treatments. Expression profiling revealed a differential expression pattern of TaEIL1 under different treatments. The expression pattern of TaEIL1 genes was upregulated under Cd stress but downregulated under combined ZnO-NPs and PGPR, revealing its crucial role in Cd stress tolerance. Inferentially, ZnO-NPs and PGPR showed significant potential to alleviate Cd toxicity in wheat by modulating the antioxidant defense system and TaEIL1 expression. By inhibiting Cd uptake, and facilitating their detoxification, this innovative approach ensures food safety and security.

Antibacterial and antibiofilm effect of Zinc Oxide nanoparticles on P. aeruginosa variants isolated from young patients with cystic fibrosis.

BACKGROUND: P. aeruginosa, a biofilm-forming bacteria, is the main cause of pulmonary infection in CF patients. We applied ZnO-np as a therapeutic agent for eradicating multi-drug resistance and biofilm-forming P. aeruginosa isolated from young CF patients. METHODS: A total of 73 throat and sputum samples taken from young CF patients were inquired. ZnO-np was synthesized and characterized in terms of size, shape, and structure for anti-bacterial activity. The antibiotic susceptibility of isolates before and after the addition of 16 µg/ml of ZnO was evaluated using disc diffusion and microtiter methods, respectively. The gene expression level of QS genes was assessed after treatment with 16 µg/ml ZnO-np. RESULTS: The optimum concentration of ZnO-np with a higher inhibitory zone was 16 µg/ml (MIC) and 32 µg/ml (MBC). All isolates were resistant to applied antibiotics, and about 45 % of isolates were strong biofilm-forming bacteria. After treatment with 16 µg/ml ZnO-np, all strains became susceptible to the applied antibiotic except for amikacin, which confers an intermediate pattern. About 63 % and 20 % of isolates were, respectively, non-biofilm and weak biofilm-forming bacteria following the addition of ZnO-np. Relative gene expression of gacA, lasR, and rhlR genes were downregulated significantly (P < 0.001). Although the retS did not have a significant reduction (P = 0.2) CONCLUSION: ZnO-np at a concentration of 16 µg/ml could significantly reduce the P. aeruginosa infection by altering the antibiotic susceptibility pattern and inhibiting biofilm formation. Due to their photocatalytic properties and their ability to penetrate the extracellular polysaccharide layer, ZnO nanoparticles can produce ROS, which increases their susceptibility to antibiotics. Nasal delivery of ZnO-np in the form of aerosol can be considered a potential strategy to decrease the mortality rate in CF patients at an early age.

Cyanide Linkage Isomerization Induced by Cobalt Oxidation-State Changes at a Co-Fe Prussian-Blue Analogue/ZnO Interface.

Understanding the interfacial composition in heterostructures is crucial for tailoring heterogenous electrochemical and photoelectrochemical processes. This work aims to elucidate the structure of a series of Co-Fe Prussian blue analogue modified ZnO (PBA/ZnO) electrodes with interface-sensitive vibrational sum frequency generation (VSFG) spectroscopy. Our measurements revealed, for the first time, a cyanide linkage isomerism at the PBA/ZnO interface, when the composite is fabricated at elevated temperatures. In situ VSFG spectro-electrochemistry measurements correlate the CoII➝CoIII oxidation with the flip of the bridging CN ligand from Co-NC-Fe coordination mode to a Co-CN-Fe one.  Photoluminescence measurements and X-ray photoelectron spectroscopy reveal that this unprecedented linkage isomerism originates from surface defects, which act as oxidation sites for the PBA. The presence of such surface defects is correlated with the fabrication temperature for PBA/ZnO. Thus, this contribution identifies the interplay between the surface states of the ZnO substrates and the chemical composition of PBA at the ZnO surface, suggesting an easily accessible approach to control the chemical composition of the interface.

Ferula latisecta gels for synthesis of zinc/silver binary nanoparticles: antibacterial effects against gram-negative and gram-positive bacteria and physicochemical characteristics.

This study explores the potential antibacterial applications of zinc oxide nanoparticles (ZnO NPs) enhanced with silver (Ag) using plant gel (ZnO-AgO NPs). The problem addressed is the increasing prevalence of pathogenic bacteria and the need for new, effective antimicrobial agents. ZnO NPs possess distinctive physicochemical properties that enable them to selectively target bacterial cells. Their small size and high surface area-to-volume ratio allow efficient cellular uptake and interaction with bacterial cells. In this study, the average size of the synthesized ZnO-Ag nanoparticles was 77.1 nm, with a significant standard deviation of 33.7 nm, indicating a wide size distribution. The nanoparticles demonstrated remarkable antibacterial efficacy against gram-negative and gram-positive bacteria, with inhibition zones of 14.33 mm for E. coli and 15.66 mm for B. subtilis at a concentration of 300 µg/ml. Minimum inhibitory concentrations (MIC) were determined to be 100 µg/ml for E. coli and 75 µg/ml for S. saprophyticus. Additionally, ZnO-Ag NPs exhibited excellent biocompatibility, making them appropriate for various pharmacological uses. This study utilizes Ferula latisecta gels, offering a sustainable and eco-friendly approach to nanoparticle synthesis. Incorporating of Ag into ZnO NPs significantly enhances their antimicrobial properties, with the combined results showing great inhibition effects on pathogenic microbes. The findings suggest that ZnO-Ag NPs could be a promising candidate for addressing the challenges posed by drug-resistant bacterial infections and enhancing antimicrobial treatments.

Novel furfural-complexed approach to synthesizing carbon-Doped ZnO with breakthrough photocatalytic efficacy.

INTRODUCTION: The efficiency of zinc oxide (ZnO) nanoparticles for environmental decontamination is limited by their reliance on ultraviolet (UV) light and rapid charge carrier recombination. Carbon doping has been proposed to address these challenges by potentially enhancing visible light absorption and charge separation. OBJECTIVES: This study aims to introduce a novel, single-step synthesis method for carbon-doped ZnO (C-Z) nanoparticles, leveraging the decomposition of zinc nitrate hexahydrate and furfural under a nitrogen atmosphere to improve photocatalytic activity under visible light. METHODS: A series of C-Z variants (C-Z-1 to C-Z-5) and an undoped sample (ZnO-0) were synthesized. The influence of furfural on the synthesis process and doping mechanism was analyzed by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and UV-visible diffuse reflectance spectroscopy (DRS). RESULTS: XPS confirmed the integration of carbon within the ZnO matrix, and XRD indicated increased lattice dimensions owing to doping. DRS revealed bandgap narrowing, suggesting enhanced charge separation. Among the variants, C-Z-3 significantly outperformed the others, showing a 12-fold increase in the photocatalytic degradation rate of Rhodamine B compared to undoped ZnO. CONCLUSION: The developed single-step synthesis method for C-Z nanoparticles represents a major advancement in materials engineering for ecological applications. The enhanced photocatalytic activity under visible light, as demonstrated by C-Z-3, underscores the potential of these nanoparticles for environmental decontamination.

Piezophototronic Effect Enhanced Flexible Tunneling Devices by Separating the Photosensitive Layer and the Piezoelectric Modulation Layer.

The piezo-phototronic effect uses the piezoelectric potential/piezoelectric charge generated by the piezoelectric semiconductor material to regulate the energy band structure and photogenerated carrier behavior at the interface/junction, thereby modulating the device's performance. The positive/negative piezoelectric charges generated at the interface of piezoelectric semiconductors can reduce the electron/hole barriers and thus enhance the transport of photogenerated carriers. However, electron/hole potential wells are formed when the electron/hole potential barrier caused by positive/negative piezoelectric charges is lowered too much, hindering the transport of photogenerated carriers. It is difficult to balance the relationship between potential barriers and potential wells while introducing the piezo-phototronic effect. In this work, a physical mechanism by separating the photosensitive layer and the piezoelectric modulation layer is proposed to deal with the above-mentioned issue in flexible tunneling devices. The piezoelectric modulation layer is solely used to adjust the electron/hole barriers, while the photosensitive layer is used to absorb photons and generate photogenerated carriers. This avoids the limitation on the transport of photogenerated carriers caused by potential wells in the piezoelectric semiconductor, thereby significantly increasing the adjustable range of the barriers. Experimental results show that the photoresponsivity of the flexible p-Si/Al2O3/n-ZnO tunneling device is optimized from 5.5 A/W to 35.8 A/W by the piezo-phototronic effect after separating the piezoelectric charges and photogenerated carriers. In addition, finite element analysis is used to simulate the influence of piezoelectric charges on the energy bands to corroborate the accuracy of the theoretical mechanism and experimental results. This work not only presents an optoelectronic device with excellent performance but also offers novel guidance for improving the performance of optoelectronic devices using the piezo-phototronic effect.

Toxicity of inorganic nanoparticles and commercial sunscreens on marine bacteria.

The Balearic Islands, a top tourist destination for sunny beaches, face physical and chemical pressures from human activities, impacting keystone species like the endemic seagrass Posidonia oceanica and its associated microbiome. This study evaluated the effects of ZnO and TiO2 nanoparticles and three commercial sunscreens with varying protection factors (50 or 90) and chemical complexities (1- SPF50_E "eco-friendly"; 2- SPF50 not "eco-friendly"; 3- SPF90 not "eco-friendly") on five heterotrophic bacteria (Pseudomonas azotifigens, Marinobacterium litorale, Thiothrix nivea, Sedimenticola thiotaurini and Cobetia sp) and two autotrophic cyanobacteria (Halothece sp. and Fischerella muscicola) associated to P. oceanica, as well as a natural leaf epiphytic community. Results indicated that TiO2 affected all heterotrophic bacteria, while ZnO was toxic to only two species, while autotrophs were unaffected. Commercial sunscreens impacted three heterotrophs and the natural epiphytic community, while autotrophs were only affected by SPF50. SPF50_E reduced phosphorus uptake, and both SPF50 and SPF90 decreased alkaline phosphatase activity. Reactive oxygen species production was mainly induced by SPF90, followed by SPF50_E and SPF50. Generally, the smallest bacteria were most sensitive to UV-filters (UVFs). This study indicates that UVFs exposure may alter the epiphytic community structure of P. oceanica.

Influence of Substrate Location and Temperature Variation on the Growth of ZnO Nanorods Synthesized by Hot Water Treatment.

Hot water treatment (HWT) is a versatile technique for synthesizing metal oxide nanostructures (MONSTRs) by immersing metal substrates in hot water, typically in glass beakers. The proximity of substrates to the heat source during HWT can influence the temperature of the substrate and subsequently impact MONSTR growth. In our study, zinc (Zn) substrates underwent HWT at the base of a glass beaker in contact with a hot plate and at four different vertical distances from the base. While the set temperature of deionized (DI) water was 75.0 °C, the substrate locations exhibited variations, notably with the base reaching 95.0 °C. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and Raman spectroscopy showed stoichiometric and crystalline zinc oxide (ZnO) nanorods. ZnO rods on the base, exposed to higher temperatures, displayed greater growth in length and diameter, and higher crystallinity. Nanorods with increasing vertical distances from the base exhibited a logarithmic decrease in length despite identical temperatures, whereas their diameters remained constant. We attribute these findings to crucial HWT growth mechanisms like surface diffusion and "plugging", influenced by temperature and water flow within the beaker. Our results provide insights for optimizing synthesis parameters to effectively control MONSTR growth through HWT.

Temperature-Sensitive Template for Preparation of ZnO/CeO2 Composite Photocatalytic Materials and Its Catalytic Performance.

In this work, a series of thermosensitive ionic liquid functionalized polymers, PNx(IL)y, with controllable morphology and particle size were prepared by free radical polymerization. Then, using the polymer PN64(IL)8 with uniform morphology as a templating agent, the ZnO composite photocatalytic materials doped with rare earth metal Ce were prepared in combination with a microwave-assisted and templated hydrothermal reaction method. Series different Ce-doping amount photocatalytic materials ZnO-Ce-x‱ were characterized by XRD, SEM, TEM, XPS, and other methods. The results demonstrated that the templated materials PN64(IL)8 can prepare ZnO-Ce-2‱ with uniform petaloid ambulacra shape, good distribution of elements, and excellent photocatalytic performance. Photocatalytic degradation experiments of methyl orange (MO) showed that when the Ce-doping amount is only 2‱, the degradation rate of organic dyes can reach 96.5% by reacting the photocatalytic materials in water for 1 h. In addition, this kind of photocatalyst can be used for the degradation of high-concentration MO, as well as being easily recovered and effectively reused by simple filtration. Therefore, the structure of this kind of photocatalyst is controllable in the preparation process with an extremely low Ce-doping amount compared with current reports, and it has a good application prospect in the field of wastewater treatment technology.

Functionalization of Artwork Packaging Materials Utilizing Ag-Doped TiO2 and ZnO Nanoparticles.

Most of the artworks stored in museums are often kept in inappropriate climatic and environmental conditions that facilitate the formation and growth of microorganisms, such as fungi, which are responsible for many types of biodegradation phenomena. To mitigate and prevent these deteriorative processes, functionalized packaging materials can be used for the storage and handling of artworks. The aim of this study was to develop a potential anti-biodeterioration coating suitable for packaging purposes. TiO2 and ZnO doped with different amounts of Ag (0.5 wt%, 1 wt%, and 3 wt%) were synthesized and dispersed in polyvinyl alcohol (PVA) and acrylic resin (Paraloid B72), then applied on different types of packaging materials (cellulose and the high-density spunbound polyethylene fiber Tyvek®, materials that are frequently used as packaging in museums). Analytical investigations (SEM/EDS, Raman, FTIR, and XRD) were employed to assess dispersion on the packaging material. Furthermore, resistance against biodeteriogens was assessed using Cladosporium sp., a bioluminometer, to define the biocidal efficacy.

How Nano-ZnO Affect Tomato Fruits (Solanum lycopersicum L.)? Analysis of Selected Fruit Parameters.

Tomato (Solanum lycopersicum L.), as one of the most valuable horticulture crops, was chosen to investigate the effect of nanoparticles (NPs) in the form of nano-ZnO combined with conventional fertilizer on the quality of tomato fruits, including their antioxidant potential (total antioxidant activity, lycopene and ß-carotene content), sugars content and allergenic potential (profilin and Bet v 1 content). Nano-ZnO was implemented during plant cultivation, applied by foliar spraying or directly via soil, at three different concentrations (50, 150 and 250 mg/L). The obtained results suggest that the usage of NPs during tomato plant cultivation had minor impacts on parameters such as total antioxidant activity or the content of selected allergens. Even though the total antioxidant activity was not affected by nano-ZnO, the malondialdehyde activity (MDA) content was notably decreased in fruits under nano-ZnO treatment. The content of lycopene and ß-carotene was significantly affected by the use of nano-ZnO. Moreover, the usage of nano-ZnO significantly increased the total sugar content in fruits treated with nanoparticles via foliar spraying. Based on the obtained results, it can be stated that nano-ZnO, regardless of the method of application, significantly affected tomato fruits which can be beneficial for fruit production.

Photo-induced metal-oxide biosensor for analysis of biofluids.

Determining the concentration of biomarkers offers insights into the health condition and performance of the body. The majority of the biosensors applied to measuring biomarkers in biological fluids are electrochemical bases; however, these biosensors suffer from several key drawbacks. These include utilizing complex sensing materials to obtain desirable analytical performance, which prevents their practical application; and operation at a relatively high potential, which leads to inaccurate measurements due to the undesired oxidation of non-target molecules. A novel photo-induced chemiresistive biosensor is introduced here that addresses these challenges. A UV-induced ZnO nanorod (NR) chemiresistive biosensor is developed and applied to monitoring lactate and glucose, as model biomarkers in sweat. The detection mechanism of lactate based on its interaction with ZnO NRs is proposed. Furthermore, the effect of the electrode design and operating parameters, including irradiance, radiation wavelength, and applied potential, are evaluated. The highest response, the shortest response time, and complete recovery are obtained at 5.6 mW/cm2 irradiance of 365 nm and 0.1 V potential. The results indicate that the developed transduction platform utilizing a simple sensing layer is a promising technique with excellent analytical performance for detecting different biomarkers, thereby paving the way toward the emergence of photo-induced chemiresistive biosensors for real-life applications.

Mitigating Zn Dendrite Growth and Enhancing the Utilization of Zn Electrode in Aqueous Zn-Ion Batteries.

In spite of extensive research and appreciable progress, in aqueous zinc-ion batteries, Zn metal anode is struggling with low Zn utility and poor cycling stability. In this study, a 3D "electrochemical welding" composite electrode is designed by introduction of ZnO/C nanofibers film to copper foils as an anode according to pre-electrodeposition active Zn (Zn@ZnO/C-Cu). The flow of Zn2+ through carbon fiber layer is regulated by zincophilic ZnO, promoting homogeneous diffusion of Zn2+ to Cu foil. In subsequent Zn deposition/stripping processes, the hydrophobicity of ZnO/C fiber layer reduces water at the interface of Zn@ZnO/C-Cu and results in uniform electric field significant suppressing growth of Zn dendritic and side reactions. Thus, pre-electrodeposition active Zn electrochemical welds ZnO/C nanofibers and Cu foil collectively provide stable charge/electron transfer and stripping/plating of Zn with low polarization and excellent cycling performance. The assembled symmetrical batteries exhibit stable cycling performance for over 470 h under 20% utilization of Zn at 5 mA cm-2, and an average coulombic efficiency of 99.9% at low negative/positive capacity ratio (N/P = 1) after 1000 cycles in the Zn@ZnO/C-Cu||Na2V6O16·1.5H2O full cell.

Excellent adsorption of toxic Cd (II) ions from water with effective antibacterial activity by novel GO-ZnO-curcumin composite.

A significant health risk arises from the bioaccumulation of harmful Cd (II) in drinking water. Here, we report the unique Cd (II) remediation from drinking water by using novel GO-ZnO-curcumin composite. The composites were tailored by varying the ratio of GO-ZnO and curcumin. The composites followed Langmuir adsorption isotherm and pseudo-second-order kinetics. ZnO nano-rods were more effective in Cd (II) than ZnO nano-disks. A maximum adsorption capacity of 4580 ± 40 mg/gm was achieved for 21G-B with a removal efficiency of 87.5% at neutral pH under optimized conditions. The removal process was governed by ion exchange and electrostatic attraction, followed by cation exchange capacity (CEC). The lattice parameter increase was detected after adsorption of Cd (II) ions. The regeneration and reusability of the composite was studied. Also, the effect of presence of dyes such as methylene blue on Cd (II) adsorption was noted. The latter had negligible effect on Cd (II) removal efficiency from water. The composite showed high antibacterial activity against B. subtilis and P. aeruginosa with minimum inhibitory concentration (MIC) of 10 ± 0.75 µg/ml and 5 ± 1 µg/ml respectively due to the presence of zinc. Composite stability was confirmed through leaching and thermal gravimetric analysis (TGA) analysis. The study establishes the nanocomposite as a potential material for remediation of hazardous Cd (II) ions from real water samples under neutral conditions.

Optimizing photocatalytic performance with Ag-doped ZnO nanoparticles: Synthesis and characterization.

The development of nanotechnology has significantly impacted the improvement of photocatalytic performance of ZnO NPs. In this study synthesis of pure ZnO and Ag-ZnO nanoparticles via a co-precipitation method at varying Ag concentrations (1 %, 2 %, 3 %, 4 % and 6 %) to enhance their photo catalytic efficacy. X-ray diffraction (XRD) analysis estimates crystallite size which decreased by increasing Ag concentration, ranging from 30.6 nm (Pure ZnO) to 22.5 nm 6 % Ag-doped ZnO. Scanning electron microscopy (SEM) revealed decrease in particle size with increasing Ag content. UV-Vis spectroscopy indicating a narrowed band gap of optimal sample. Photocatalytic activity of the synthesized nanoparticles was evaluated using methylene orange (MO) dye degradation under light irradiation. The MO concentration exhibited a decrease with increasing irradiation time in the presence of photocatalysts. Recombination rate of NPs decreases by increasing the concentration of Ag i.e. 4%Ag dope ZnO NPs have lowest recombination rate and maximum degradation efficiency. FTIR analysis confirms the preparation of Ag-doped ZnO NPs. This improvement can be credited to the synergistic effect of Ag doping, leading to a narrowed band gap and potentially maximum degradation of MO by using Ag-doped ZnO NPs.

A Flexible MXene-Black Phosphorus/Zinc Oxide Hybrid Structure with Excellent UVA-Specific Photoelectric Sensing Properties for Human Skin Protection.

Ultraviolet A (UVA) radiation causes various irreversible damages to human skin, so the research about UVA-specific sensing device is urgent. 2D black phosphorus (BP) is used in many photosensors due to its advantages of high carrier mobility and tunable bandgap, but its application for UVA-specific photosensor is not reported. Here, a MXene-BP/Zinc oxide (ZnO) hybrid structure with lamellar-spherical interfaces like finger lime fruit is prepared by the layer-by-layer assembly (LLA) method, and p-n junctions are constructed between BP and ZnO with the Ti3C2Tx electrode, showing excellent photoelectric performance. Density functional theory (DFT) calculations demonstrate that the enhanced performance is attributed to the rapid separation of photogenerated carriers in the presence of a built-in electric field at interface. Furthermore, a flexible MXene-BP/ZnO based UVA-specific photosensor is prepared, which shows a specific response to UVA as high as 7 mA W-1 and excellent mechanical stability, maintaining 98.46% response after 100 bending cycles. In particular, the integrated anti-UVA skin protection device shows excellent UVA-specific identification and wireless transmission capability, which can provide timely UVA exposure information and skin protection warning for the visually impaired. This work demonstrates a new approach for further developments of advanced photoelectric sensing technology toward improving people's skin health protection.

In-situ electrospinning PVB/Camellia oil/ZnO-TiO2 nanofibrous membranes with synergistic antibacterial and degradation of ethylene applied in fruit preservation.

This work utilizes a handheld electrospinning device to prepare a novel nanofibrous composite membrane in situ for packaging freshness. It can realize pick-and-pack and is easy to operate. The nanofibrous membrane is based on PVB as the matrix material, adding Camellia oil (CO) and ZnO-TiO2 composite nanoparticles (ZT) as the active material. The antimicrobial property of the CO and the photocatalytic activity of the nanoparticles give the material good antimicrobial and ethylene degradation functions. Meanwhile, this nanofibrous membrane has good mechanical properties, suitable moisture permeability and good optical properties. The nanofibrous membrane are suitable for both climacteric and non- climacteric fruits. Its use as a cling film extends the shelf life of strawberries by 4 days and significantly slows the ripening of small tomatoes. Therefore, this nanofibrous membrane has great potential for application in the field of fruit preservation.

Corrosion behavior of predominant Halodesulfovibrio in a marine SRB consortium and its mitigation using ZnO nanoparticles.

Formation of Sulfate Reducing Bacteria (SRB) biofilm accelerates microbiologically influenced corrosion (MIC). The aim of this study was to investigate both the corrosivity of a marine SRB consortium on carbon steel coupons and its mitigation in the presence of ZnO. Metagenomics analysis revealed that Halodesulfovibrio (78.9%) was predominant and could be related to MIC. The analysis also showed a remarkable shift from a highly corrosive SRB consortium in the control bioreactors to a far less corrosive consortium when ZnO was added to the bioreactors. Further results indicated that the corrosion rate of the SRB consortium was 8.17 mpy on the carbon steel coupons. In the ZnO-treated bioreactors, the count of SRB and MIC in the carbon steel coupons simultaneously reduced. Moreover, Confocal Laser Scanning Microscopy and profilometry analysis determined that ZnO could significantly decrease the amount of biofilm and the corrosion rate. Electrochemical experiments revealed higher corrosion current density (icorr) and lower charge transfer resistance (Rct) in the control bioreactors relative to the ZnO-treated bioreactors. We introduce Halodesulfovibrio as a potentially important corrosive genus in a marine SRB consortium. Additionally, ZnO could be considered a proper candidate to control the corrosion induced by Halodesulfovibrio.

Study of ZnO nanoparticle-doped dental adhesives on enamels with fluorosis: Electron microscopy, elemental composition and shear bond strength analysis.

This study aimed to evaluate dental adhesives containing different concentrations of zinc oxide nanoparticles (ZnO-NPs) for their use in the treatment of dental fluorosis, observe the interaction of the adhesive on healthy enamel surfaces and with mild and moderate fluorosis, measure the adhesive strength and fluorosis, and determine the phosphorus (P) and calcium (Ca) content on these surfaces, as a reference for the potential use of this adhesive with ZnO-NPs for dental fluorosis treatment. Transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM) were used to characterise the ZnO-NPs and analyse the weight percentages of P and Ca in the enamel using X-ray energy dispersive spectroscopy (EDS) and the adhesive strength using a universal mechanical testing machine. FESEM characterisation revealed that the ZnO-NPs were less than 100 nm in size, with quasi-spherical and hexagonal prism shapes. The synthesis of the ZnO-NPs was confirmed by TEM, revealing their hexagonal crystalline structure. The adhesive strength by the universal mechanical testing machine showed that the adhesive with a 3% wt. concentration of ZnO-NPs was better in the three groups of teeth, showing higher adhesive strength in teeth with mild (15.15 MPa) and moderate (12.76 MPa) fluorosis surfaces, and was even higher than that in healthy teeth (9.65 MPa). EDS analysis showed that teeth with mild and moderate fluorosis had the highest weight percentages of P and Ca, but there were no statistically significant differences compared to healthy teeth and teeth treated with adhesives. Lay description: This study focused on testing a new dental adhesive containing small particles called ZnO nanoparticles (ZnO-NPs). This study aimed to demonstrate whether this adhesive with ZnO-NPs could be useful for treating dental fluorosis by improving its adhesion to teeth. One of the first objectives was to determine whether the dental adhesive could adhere better to teeth affected by mild or moderate fluorosis than to healthy teeth by measuring whether the levels of two important elements for healthy teeth, calcium (Ca) and phosphorus (P), were affected by the adhesive. The size and shape of the small particles and teeth with mild or moderate fluorosis were observed using scanning electron microscopy. The nanoparticles were small (< 100 nm) and had specific quasi-spherical and hexagonal prismatic shapes. More damage to the enamel was observed in teeth with mild or moderate fluorosis than in healthy teeth. The adhesive strength test demonstrated that the dental adhesive with 3% ZnO-NPs had the best adhesion on all healthy conditions of teeth. It was particularly effective in teeth with mild or moderate fluorosis. Finally, the evaluation of the levels of P and Ca on the enamel showed that teeth with fluorosis had higher levels of these elements, but using the dental adhesive with ZnO-NPs did not change the levels of these elements significantly because the adhesive avoided greater detachment because of greater adhesion to these surfaces. In conclusion, adding these small particles to dental adhesives could be an option for treating teeth affected by fluorosis. It stuck well and did not affect the levels of the important elements in the teeth.

Antibacterial properties and application of Bi2Sn2O7/ZnO composite photocatalytic materials.

In this experiment, Bi2Sn2O7/ZnO composite photocatalytic materials were synthesized by a hydrothermal method and characterized by XRD, SEM, and EDS, etc. The prepared Bi2Sn2O7/ZnO has a nanorod structure and high phase purity. The photocatalytic antimicrobial performance of Bi2Sn2O7/ZnO against bacteria and fungi under visible light was significantly better than that of single Bi2Sn2O7 and ZnO. In particular, 1000 mg/L 1:3 Bi2Sn2O7/ZnO showed an antimicrobial rate of more than 97% against Escherichia coli, Staphylococcus aureus, and Candida albicans, which are widely present in the nature. The free radical trapping experiments were selected and the antimicrobial mechanism was investigated, and the results showed that the antimicrobial process of the Bi2Sn2O7/ZnO system was regulated by the free radicals such as ·OH, h+, and e-, which were generated by its unique photocatalytic activity. Finally, MTT cytotoxicity experiments demonstrated that the Bi2Sn2O7/ZnO composite was not toxic to cells. In addition, the antimicrobial performance of Bi2Sn2O7/ZnO on real livestock wastewater and the real-life application of the prepared Bi2Sn2O7/ZnO PCL composite antibiotic film for antimicrobial treatment of freshly cut fruits' surfaces under visible light were experimentally investigated. This study provides a new idea for Bi2Sn2O7/ZnO as a photocatalytic antimicrobial agent.