In vitro antibacterial response of ZnO-MgO nanocomposites at various compositions

ZnO-MgO nanocomposites were prepared by a co-precipitation method and afterward compared with pristine ZnO and MgO accordingly. XRD and EDX spectra were used to confirm the crystal structure and crystallite size of these materials. X-ray diffraction analysis shows that antibacterial activity of ZnO:MgO composite enhances with crystallite size reduction ~1.34 times in comparison to pristine ZnO or MgO specimens, accompanied by domination of defect generation over defect annihilation activity. Besides, average particle sizes also reduce to ~2 times at 1:3 MgO/ZnO composite in comparison to MgO. The particle size of ZnO was substantially higher due to rod-like morphology. Moreover, the minimum inhibitory concentration outcomes also show that ZnO-MgO composites are more effective against gram-negative pathogens in appropriate ratios (ZnO:MgO) of 1:3 and 3:1 with the concentration of 15,000 µg/ml. Similarly, gram-positive pathogens were In contrast, ZnO and MgO separately or in 1:1 composite ratio does not prove considerably effective on all the five microbes (required higher >25,000 µg/ml) MIC to counter gram-negative pathogens. Additionally, lower doses of 3ZnO:1MgO and 1ZnO:3MgO ~5000 µg/ml composite nanoparticles are effective on gram-positive pathogens. Similarly, 3ZnO:1MgO composition proved highly productive at a much lower concentration, that is, 12500 ≤ X ≤ 15000 to counter gram-negative pathogens. Besides, 1ZnO:3MgO is effective against gram-negativepathogens at MIC ranging from 12500 ≤ X ≤ 15000 µg/ml.     

In situ synthesis of fluorapatite-ZnO nanocomposite powder via mechanical alloying for biomedical applications

This research aimed to synthesize of fluorapatite(FA)–ZnO (FAZ) nanocomposite powder using a one-step mechanical alloying process without any post-calcification process. Furthermore, the role of various concentrations of ZnO (0, 4, 8, 11, and 15 wt.%) on the chemical and biological characteristics of FA was examined. Our research confirmed the successful synthesize of FAZ nanopowders with irregular-shaped particles and particle size of 38-52 nm. The crystallinity, crystallite size, and c-axes parameter of FA decreased with increasing ZnO content. Moreover, while all FAZ powders revealed superior bioactivity than FA, FA-8 wt.% ZnO nanopowder significantly enhanced MG63 cell proliferation. Besides, between various samples, FA-11 wt.% ZnO nanopowder revealed drastically greater antibacterial activity. It could be concluded that the in-situ synthesis of FAZ powder meaningfully improved the biological activity of FA making it a promising coating for orthopedic and dental implants.     

Structural,optical, cytotoxicity,and antimicrobial properties of MgO,ZnO and MgO/ZnO nanocomposite for biomedical applications

In this study, MgO nanoparticles were successfully fabricated and incubated inside ZnO NPs to form MgO/ZnO nanocomposite for biomedical applications. The x-ray diffraction analysis of MgO, ZnO, and MgO/ZnO has shown the single-phase x-ray diffraction patterns through X'pert High score. The crystallite sizes were calculated as 18 nm, 42 nm, and 53 nm, respectively. The average particle size of MgO, ZnO, and MgO/ZnO nanopowders depicted from secondary electron images of field emission electron microscopy were 56 nm, 400 nm, and 450 nm, respectively. The presence of MgO NPs inside ZnO NPs was confirmed by transmission electron microscopy. The elemental dispersive spectroscopy of MgO, given the peaks of oxygen and magnesium, also showed only zinc and oxygen peaks in ZnO, which confirms no other impurities in MgO and ZnO powders. The elemental analysis of MgO/ZnO nanocomposite showed the peaks of Zinc and Oxygen, along with a tiny peak of Mg. The photoluminescence and UV–vis spectroscopy revealed the absorbance fluorescence limit of the nanomaterials. Fourier transform infrared spectroscopy confirmed the several groups present in the nanocomposite. The biocompatibility of MgO, ZnO, and MgO/ZnO was observed with human peripheral blood mononuclear cells. The cytotoxicity studies were also performed against human cancer (liver and breast) cell lines. The MgO, ZnO, and MgO/ZnO exhibited the antimicrobial properties against Escherichia coli and Staphylococcus aureus.     

Silver-zinc oxide nanocomposite: From synthesis to antimicrobial and anticancer properties

A green method by Verbascum speciosum was used to synthesize zinc oxide nanoparticles (ZnO NPs). ZnO NPs were coated with silver to synthesize Ag–ZnO nanocomposite (NCs). The physicochemical properties of Ag–ZnO NCs were analyzed by Fourier-transform infrared spectroscopy (FTIR), powder X-ray diffraction (PXRD), field emission scanning electron microscope (FESEM), transmission electron microscopy (TEM), dynamic light scattering (DLS), and zeta potential. The FTIR indicated the peak of Zn–O vibration and some hydroxyl and carboxyl groups. PXRD analyses confirmed the synthesis of ZnO NPs and Ag–ZnO NCs. Due to the size of the crystallite obtained from PXRD, solid-phase sizes (from FESEM and TEM images), and dynamic sizes from DLS, agglomeration was observed. The Ag–ZnO NCs showed a negative charge surface (?49.3 mV). Ag–ZnO NCs had a high antibacterial activity towards two most important infectious bacteria (i.e., Escherichia coli and Staphylococcus aureus) and anticancer activity against human liver-carcinoma cells (HepG2). Later, it depended on time and concentration of Ag–ZnO NCs. The cytotoxicity properties of Ag–ZnO NCs were also studied against NIH-3T3 as a normal cell, where the results verified the lower cell toxicities of nanocomposite than the HepG2.     

Preparation and antibacterial properties of titanium-doped ZnO from different zinc salts

To research the relationship of micro-structures and antibacterial properties of the titanium-doped ZnO powders and probe their antibacterial mechanism, titanium-doped ZnO powders with different shapes and sizes were prepared from different zinc salts by alcohothermal method. The ZnO powders were characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), ultraviolet-visible spectroscopy (UV-vis), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and selected area electron diffraction (SAED), and the antibacterial activities of titanium-doped ZnO powders on Escherichia coli and Staphylococcus aureus were evaluated. Furthermore, the tested strains were characterized by SEM, and the electrical conductance variation trend of the bacterial suspension was characterized. The results indicate that the morphologies of the powders are different due to preparation from different zinc salts. The XRD results manifest that the samples synthesized from zinc acetate, zinc nitrate, and zinc chloride are zincite ZnO, and the sample synthesized from zinc sulfate is the mixture of ZnO, ZnTiO₃, and ZnSO₄ · 3Zn (OH)₂ crystal. UV-vis spectra show that the absorption edges of the titanium-doped ZnO powders are red shifted to more than 400 nm which are prepared from zinc acetate, zinc nitrate, and zinc chloride. The antibacterial activity of titanium-doped ZnO powders synthesized from zinc chloride is optimal, and its minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) are lower than 0.25 g L⁻¹. Likewise, when the bacteria are treated by ZnO powders synthesized from zinc chloride, the bacterial cells are damaged most seriously, and the electrical conductance increment of bacterial suspension is slightly high. It can be inferred that the antibacterial properties of the titanium-doped ZnO powders are relevant to the microstructure, particle size, and the crystal. The powders can damage the cell walls; thus, the electrolyte is leaked from cells.     

Optical properties of Yb-doped ZnO/MgO nanocomposites

Yb³⁺ doped ZnO/MgO nanocomposite were prepared by combustion synthesis method. The samples were further heated to 1000 °C to improve their crystallinity and photoluminescent efficiency. The concentrations of Yb³⁺ and Mg²⁺ were varied between 1–2% and 5–70% respectively in prepared samples. The nano-powders were characterized by Scanning Electron Microscopy and X-ray Diffraction for morphology and structural determination. XRD studies have revealed the wurtzite structure for Mg_xZn_1−xO for Mg concentrations below 30%. Higher concentrations of Mg results in Yb³⁺ doped ZnO/MgO nanocomposite containing three phases; the wurzite hexagonal phase typical of ZnO, the cubic phase of MgO and a small amount of cubic Yb₂O₃ phase. As expected, the amount of cubic phase in nano-powders increased with the increase of Mg concentration in ZnO. The crystallite size of ZnO/MgO composites decreased from 55 nm to 30 nm with increase of Mg content. SEM images of Yb³⁺ doped ZnO/MgO nanocomposite with higher Mg content (>50%) showed clearly distinct hexagonal and cubical shaped nano-particles. Photoluminescent emission showed a broad band in the range (435 nm to 700 nm). Pure ZnO nano-phosphor showed an emission peak around 545 nm, which is blue shifted with Mg content. The photoluminescence intensity increased with increase of Mg content in ZnO and it became maximum with 30% Mg concentration. Time resolved decay curves of photoluminescence indicated decay time in microsecond time scale.     

Effects of SiC nanoparticles on synthesis and antimicrobial activity of TiCu nanocrystalline powder

Effects of SiC nanoparticles addition on synthesis and antibacterial properties of TiCu nanocrystalline powder prepared through high energy mechanical milling were studied. The results showed that the synthesis of TiCu powder in the presence of the nanoparticles was accelerated and after mechanical alloying for 20 h, a TiCu/SiC nanocrystalline powder with the crystallite size <5 nm, and 3.3% lattice micro-strain obtained. Further milling resulted in fully amorphous TiCu intermetallic alloy with more uniform distribution of SiC nanoparticles. The antibacterial activity of the synthesized powders was investigated by disk diffusion test. The TiCu/SiC nanocomposites showed enhanced antibacterial effect against S. aureus and E. coli, and with increasing SiC content, the antibacterial behaviour was improved. This behaviour is attributed to high Cu²⁺ ion release as a result of particle size refinement with increasing SiC nanoparticles.     

Antibacterial responses of zinc oxide structures against Staphylococcus aureus, Pseudomonas aeruginosa and Streptococcus pyogenes

The antibacterial responses of zinc oxide (ZnO) structures against Staphylococcus aureus, Pseudomonas aeruginosa, and Streptococcus pyogenes were investigated. Two ZnO powder samples, one with rod-like (ZnO-1) and the other with plate-like (ZnO-2) structures, were characterized for their morphological, structural, and optical properties. The rods were 30–120 nm in diameter, and the plates were 40–100 nm thick. XRD results revealed the wurtzite crystallinity of ZnO with average crystallite sizes of 33.72 (ZnO-1) and 39.25 (ZnO-2) nm. ZnO-2 possessed a relatively higher green photoluminescence than that of ZnO-1, suggesting a relatively higher amount of oxygen vacancies in ZnO-2 structures. Optical density measurements showed that both ZnO samples inhibited the growth of S. aureus, P. aeruginosa, and S. pyogenes by 29–98% after 24 h of treatment. The most dramatic growth inhibition was observed in S. pyogenes with 96% and 98% inhibition for ZnO-1 and ZnO-2, respectively, leading to a probable bactericidal phenomenon. The toxicological effect on S. pyogenes was probably due to the absence of catalase, making the bacteria vulnerable to the harmful reactive oxygen species (ROS) released by ZnO. ZnO-1 induced higher inhibition toward S. aureus and P. aeruginosa than that of ZnO-2 because of the smaller particle size of rod structures compared to plate and slab structures. The adhesion of ZnO particles on the membrane of bacteria could be the underlying cause of zinc toxicity effect towards the bacteria. ZnO-1 possessed larger surface area and provided higher amount of zinc atom, thereby inducing higher level of toxicity toward the bacteria. Two possible mechanisms were proposed to explain the inhibition of bacteria, namely, ROS toxicity toward cellular constituents and interaction of zinc with bacteria membrane through adhesion of ZnO particle. Several ZnO morphological-antibacterial correlations were presented in this work.     

ZnO超微粉末的制备与表征

以ＺｎＳＯ４·７Ｈ２Ｏ和Ｎａ２ＣＯ３为原料，采用化学法合成了ＺｎＯ超微粉末。应用Ｘ射线粉末衍射法（ＸＲＤ）测定了合成ＺｎＯ的几组晶面的衍射峰形，经数据处理得到ＺｎＯ超微粉末的平均晶粒度和晶格畸变率的定量分析结果。实验结果表明，化学法合成的ＺｎＯ超微粉末的晶粒度范围在２０ｎｍ～３５ｎｍ之间。     

Effective factor on antibacterial characteristics of Mg1−XNiXO solid solution

Mg_1−XNi_XO solid solution powder samples with different chemical compositions were prepared by heating MgO–NiO mixtures at 1300 °C for 12 h in air. From XRD measurement, all powder samples were indexed as a single phase of cubic structure, of which the diffraction peaks shifted to high-angle side with the increase of doping amount of NiO. The pH values of the solution dispersed with the powder samples decreased when the doping amount of NiO in solid solution was increased. Antibacterial activity of the powder samples was examined by colony count method. In the result, the antibacterial activity of Mg_1−XNi_XO was remarkably weaker than original MgO powders, irrespective of the kind of bacteria. In addition, it was found that the antibacterial activity of Mg_1−XNi_XO reduced with increasing the doping amount of NiO. Two factors, the generated amount of O₂⁻ and the eluted amount of Ni²⁺ ions affected the antibacterial activity of Mg_1−XNi_XO solid solution. Especially, the stability of O₂⁻ in aqueous solution is dependent on pH value. Therefore, the strength of antibacterial activity was associated with the pH values in the dispersed solution of Mg_1−XNi_XO.     

Structural and phase analysis of multi-ion doped hydroxyapatite for biomedical applications

Multi-ion doping in synthetic HA was carried out using high energy planetary ball milling followed by calcination at 1250?°C for 2?h. The influence of Sr⁺², Zn⁺², Ag⁺, and F^- ion doping on crystallinity and crystallite size was analyzed using Taguchi design of experiments (DOE) and optimal concentration of different dopants has been identified to achieve desired crystallinity and crystallite size. The doped HA samples have been characterized using X-ray diffraction and Fourier transform infrared spectroscopy to determine their phase purity, degree of crystallinity, crystallite size and functional groups. Standard Analysis of variance (ANOVA) showed relatively high contribution of Sr⁺² and Zn⁺² doping in changing the crystallinity and crystal size of HA compared to the effect of Ag⁺ and F^- doping. Our analysis demonstrated strong interaction between dopants at binary level doping, while ternary and quaternary doping of elements did not exhibit any interaction in influencing the crystallinity and crystallite size of HA. In general, multi-ion doping in HA found to decrease its crystallinity from 92% to 72% (max.), but enhance the hardness, depending on the type and concentration of doping element. Similarly, a minimum crystallite size of 31?nm was achieved with some binary compositions and other combinations resulted in crystallite sizes up to 59?nm. The compositions that ensure desired crystallinity and crystallite size can also provide high hardness. Our results can be used to tailor the composition of HA in achieving desired functional properties, dependent on crystallinity and crystallite size, such as strength, bioactivity and degradation to suit variety of implant applications.     

Photocatalytic degradation of Rhodamine B dye under UV/solar light using ZnO nanopowder synthesized by solution combustion route

Nano-sized ZnO powder with crystallite size in the range 12 to 50 nm were prepared by solution combustion route. The product was characterized by powder X-ray diffraction (PXRD), scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR). Photocatalytic degradation of rhodamine B (RB) dye was carried out with ZnO nanopowder. The effect of parameters such as the crystallite size, amount of catalyst, concentration of the dye, pH and irradiation on photocatalytic degradation of RB is studied. The results reveal that the maximum decolorization (more than 95%) of dye occurred with ZnO catalyst in 8 min of stirring at basic pH under solar light irradiation. It was also found that chemical oxygen demand (COD) reduction takes place at a faster rate under solar light as compared to that of UV light. The results suggest that, the ZnO solar photocatalytic irradiation is better than the calcined ZnO/solar and UV light irradiation.     

Biosynthesized Ag–ZnO nanohybrids exhibit strong antibacterial activity by inducing oxidative stress

We report facile biosynthesis of Ag–ZnO nanohybrids consisting of Ag nanoparticles decorated ZnO nanobullets prepared by decorating wet chemically synthesized ZnO nanobullets with Ag nanoparticles through bioreduction of Ag ⁺ ions with aqueous extract of Piper nigrum fruits. The prepared nanomaterials were well characterized by FESEM, TEM, HRTEM, EDX, XRD, XPS, PL and UV–vis spectroscopy. FESEM and TEM analyses on the nanohybrids revealed ∼18 nm Ag nanoparticles decorating ZnO nanobullets with average size ∼48 nm. XRD results revealed hexagonal wurtzite ZnO with 22.4 nm crystallite size and FCC Ag with 18.7 nm crystalline size. Ag–ZnO nanohybrids exhibited strong antibacterial action against Escherichia coli, Bacillus oceanisediminis and Pseudomonas entomophila and efficiently inhibited their growth at 100 μg/mL, 50 μg/mL and 125 μg/mL, respectively. The molecular basis of antibacterial action of Ag–ZnO nanohybrids against E. coli was investigated using different biochemical and molecular assays. Addition of antioxidant histidine suppressed the antibacterial action of Ag–ZnO nanohybrids towards E. coli due to its ROS scavenging action. Bradford assay results showed enhanced protein leakage from Ag–ZnO nanohybrids treated E. coli, while TBARS assay results confirmed lipid peroxidation triggered by ROS. SEM on Ag–ZnO nanohybrids treated E. coli confirmed significant damage to the cell wall leading to morphology change. The antibacterial activity of Ag–ZnO nanohybrids against E. coli is mainly due to the ROS-induced oxidative stress, which caused enhanced lipid peroxidation, cell wall damage leading to significant protein leakage and DNA fragmentation.     

Insights into zinc and silver co-substitution over cytotoxicity,antibacterial efficacy,and bone regeneration capabilities of strontium phosphosilicate

A series of Zinc and Silver co-substituted Sr₅(PO₄)₂SiO₄ samples were developed to evaluate the induction of antibacterial properties within the parent material. Structural evaluation of the powder samples showed a good agreement of diffraction data with respective ICDD data cards, and biocompatible secondary phases were found to be present alongside the parent material. A decrease in crystallite size (<40 nm) was observed as the substitution level increased calculated from Scherrer's equation which was also evident in infrared spectra. 6% molar substitution (Zn-3% & Ag-3%) was found to be optimized concentration for the same based on biocompatibility studies involving Hemolytic and MTT assay against MG-63 cell lines. The samples were identical in morphology to Hydroxyapatite and showed excellent bone regeneration capabilities supported by secondary phases confirmed during SBF treatment studies evaluated using diffraction, IR spectra, and electron microscopy that showed signs of apatite seeding over the particles. Both Qualitative and quantitative antibacterial tests in the form of Media poisoning and CFU calculations proved successful acquisition of antibacterial properties at 6% molar substitution. Hence the proposed system can be deemed antibacterial and biocompatible for human application and further evaluated as a possible substitute for Ca–P ceramics for bone regeneration applications.     

Application of the statistical Taguchi method to optimize TiO2 nanoparticles synthesis by the hydrothermal assisted sol–gel technique

TiO₂ nanoparticles were synthesized by hydrothermal assisted sol–gel technique. The preparation parameters including pH value, the amount of water, titanium tetra isopropoxide content, temperature and time of hydrothermal process were investigated by Taguchi statistical experiments to determine the influence of synthesizing variables on the optimal conditions and to realize the highest degree of crystallinity or smallest crystallite size. X-ray diffraction (XRD) analysis and direct band gap energy (E_g) values, measured via diffuse reflectance spectra (DRS), proved that all the samples consist of anatase as a unique phase. Transmission electron microscopy (TEM) and specific surface area values showed that the sample with the smallest crystallite size could exert more effective photoactivity confirmed by measuring the decomposition rate of methylene blue. The apparent photodegradation rate constant of the sample with the smallest crystallite size was about five times greater than that of commercial TiO₂.     

Dual role of activated carbon as fuel and template for solution combustion synthesis of porous zinc oxide powders

In this work, nanosized zinc oxide (ZnO) powders were fabricated by urea–nitrate solution combustion synthesis using activated carbon as a structure-directing template and secondary fuel at different fuel–oxidant ratios. The as-synthesized powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N₂ adsorption–desorption measurements, UV–Vis diffuse reflectance spectroscopy, and photoluminescence. The effect of fuel amount on photocatalytic activity of ZnO powders was evaluated by the degradation of an azo dye Orange G. It was observed that combustion synthesis with activated carbon as a secondary fuel had a profound effect on reducing crystallite size and enhancement of specific surface area. The crystallite size of the as-synthesized powders varied from 46 to 26 nm. The ZnO powder prepared at a fuel–oxidant ratio of 1.8 possessed the small crystallite size and high specific surface area of 69 m²/g. It correspondingly resulted in the highest dye removal percentage of 99% with a rate constant of 0.027 min⁻¹. The improvement in dye degradation can be due to the synergistic interaction and interplay of enhanced surface area and catalytic ability of the photocatalyst. This study provides a simple single-step synthesis methodology to produce metal oxide nanopowders with tunable surface properties for high potential applications in catalysis, optoelectronics, and gas sensors.     

Construction of Er-doped ZnO/SiO2 composites with enhanced antimicrobial properties and analysis of antibacterial mechanism

Herein, silica carrier was used as underlying structure to prepare composite material loaded with rare earth element Er and Zn. Rare earth elements can improve antimicrobial effects of ZnO due to their specific electronic structure. Er–ZnO/SiO₂ hybrid antibacterial material was prepared through sol-gel method and its structure and morphology were characterized by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, inductively coupled plasma emission spectroscopy and Brunauer-Emmett-Teller measurements. E. coli and S. aureus were selected as model bacteria to assess antibacterial activity of prepared hybrid material by plate coating method. Er–ZnO/SiO₂ exhibited good antibacterial activity towards E. coli and S. aureus. Increase in Er³⁺ concentration from 0.12% to 1.10% led to increase in antibacterial performance followed by subsequent decrease. Improving effect of Er relied on the molar ratio of Er doped in ZnO/SiO₂ hybrid material. The optimal sample was found to be 0.60%Er–ZnO/SiO₂, with antibacterial rates of 93.71% and 70.46% against E. coli and S. aureus, respectively. Antibacterial mechanism was assessed by fluorescence detection of reactive oxygen species. In addition, flame atomic absorption spectrometry was used to measure the amount of released Zn²⁺. Results also showed that 0.60%Er–ZnO/SiO₂ hybrid material generated more reactive oxygen species, released more Zn²⁺ ions, and had the largest surface area, which improved its antibacterial rate. Thus, Er enhanced antibacterial properties of ZnO/SiO₂, providing these composite materials with great potential as antibacterial products.     

Effect of ignition temperature and fuel amount on photocatalytic activity of solution combustion synthesized ZnO

Nanocrystalline zinc oxide (ZnO) photocatalyst has been synthesized by a simple solution combustion method using zinc nitrate as the oxidizer and urea as the fuel. Effect of fuel to oxidizer ratio and ignition temperature on the mechanism of combustion synthesis, crystallinity, morphology, surface area, and optical properties were investigated by thermal analysis, X-ray diffraction (XRD), Scanning electron microscopy (SEM), Diffuse reflectance UV–Visible spectra and Photoluminescence analyses. Photocatalytic activity of the synthesized materials was evaluated by degrading an azo dye at ambient temperature and solution pH. The prepared photocatalysts at the fuel-rich condition possess small crystallite size and more surface area; consequently, a higher photocatalytic dye degradation capability.The powder samples synthesized at the fuel-oxidant ratio of 1.8 and the ignition temperature at 400 °C have shown the maximum percentage (99%) of dye degradation in 180 min. The pseudo-first order photocatalytic dye degradation rate constant of a catalyst sample synthesized at the fuel-oxidant ratio of 1.8 was 0.0253 min⁻¹and it is 3.14 and 2.88 times higher than that of samples synthesized at fuel-oxidant ratios of 0.6 and 1.The outcomes of the present article help to design more pronounced experiments for the synthesis of photocatalysts by varying ignition temperatures and fuel amounts.     

A green approach for the preparation of nanostructured zinc oxide: Characterization and promising antibacterial behaviour

In the present study, nanostructured zinc oxide (ZnO) films have been successfully synthesized using fruit extract of Viburnum opulus L. (VO) on glass slides by successive ionic layer adsorption and reaction (SILAR) procedure. The impact of VO concentrations on the structural, morphological, optical, electrical, and antibacterial attributes of ZnO films has been investigated in detail. The samples' XRD patterns present a hexagonal crystal structure with a preferential orientation along the (002) plane. The crystallite size values of ZnO samples were found to be in the ranges from 14.88 to 9.23 nm. The supplementation of VO to the synthesis solution remarkably affected the surface morphological features of the ZnO films. The optical results demonstrated that band gap energy values of the ZnO films at room temperature were decreased from 3.20 to 3.07 eV as a function of VO content in the bath solution. The films' electrical properties were determined by impedance analysis in the frequency range of 20 Hz ?1 MHz. Impedance-frequency measurements showed VO insertion to ZnO thin films cause an increase in impedance value at the low frequencies. Cole-Cole plots with a single semi-circle confirmed the contribution of grain and grain boundary for the electrical conduction process. The agar disk diffusion method was used to test the antibacterial properties of ZnO/VO inserted ZnO and inhibition zones were measured. VO inserted ZnO showed a stronger inhibitory effect on gram-positive bacteria Staphylococcus aureus (ATCC 25923) and gram-negative bacteria Escherichia coli (ATCC 35218) than ampicillin antibiotic used as a control group. In line with the promising bactericidal results of a new generation, VO inserted ZnO, the nanostructured product with this study, it can also be applied in multidrug-resistant clinical isolates obtained from patients.     

Antibacterial activity of V- doped rod-like MgO crystals decorated with nanoflake layer

In present study, we report a V doping fabrication method for obtaining rod-like MgO crystals decorated with a nanoflake layer. This novel structure has only been minimally reported in literature. Pure MgO and Mg₂V₂O₇–MgO composite materials were obtained by precipitation and impregnation methods, with vanadium added concentrations of 0–9%. The influence of V doping on crystal structure and particle morphology of MgO was investigated by scanning electron microscopy (SEM). X-ray diffraction (XRD) analysis demonstrated that MgO has a cubic structure, while X-ray photoelectron spectroscopy (XPS) revealed that V⁵⁺ exists on the surface of MgO. The specific surface areas and pore sizes of MgO composites were calculated by BET and BJH analysis. These techniques revealed that specific surface area and pore size of MgO increased due to vanadium doping. The antibacterial effects of Mg₂V₂O₇–MgO composite materials against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were assessed using a bacterial killing/colony-forming unit (CFU) assay and bacteriostatic ring method. Our results demonstrate that V doping dramatically improved antimicrobial properties of MgO, with 7 mol% doping inducing the best antibacterial activity. The antibacterial mechanisms of Mg₂V₂O₇–MgO composite material were also proposed.