Antibacterial Activity Of ZnO Research Articles

The effect of ZnO nanoparticles morphology on the barrier and antibacterial properties of hybrid ZnO/graphene oxide/montmorillonite coatings for flexible packaging

The need for eco-friendly packaging solutions is continuously increasing, with several materials being investigated to develop functional coatings able to contrast food degradation due to oxidation and bacterial growth. In this work, ZnO nanoparticles (NPs) with various morphology and size from spherical to hexagonal, dots-like and platelets-like shape, were synthesized. Hybrid coatings constituted by ZnO NPs, graphene oxide (GO) and montmorillonite (MMT) were applied onto flexible polyethylene (PE) in order to exploit the 2D nanomaterials self-assembly ability and gas barrier properties and to synergistically combine these functionalities with the antibacterial activity of ZnO. The effect of ZnO NPs morphology and the ZnO/GO/MMT relative content was explored to obtain nanostructured coatings with optimized functionality. Results evidence a correlation between oxygen permeability and microbial proliferation, allowing to reach 88 % of reduction of PE oxygen permeability and about 60 % inhibition towards Gram-positive (i.e. Weizmannia coagulans) and Gram-negative (i.e. Escherichia coli) microorganisms.

Antibacterial and Photodegradation of Organic Dyes Using Lamiaceae-Mediated ZnO Nanoparticles: A Review.

The green synthesis of zinc oxide nanoparticles (ZnO NPs) using plant extracts has been receiving tremendous attention as an alternative to conventional physical and chemical methods. The Lamiaceae plant family is one of the largest herbal families in the world and is famous for its aromatic and polyphenolic biomolecules that can be utilised as reducing and stabilising agents during the synthesis of ZnO NPs. This review will go over the synthesis and how synthesis parameters affect the Lamiaceae-derived ZnO NPs. The Lamiaceae-mediated ZnO NPs have been utilised in a variety of applications, including photocatalysis, antimicrobial, anticancer, antioxidant, solar cells, and so on. Owing to their optical properties, ZnO NPs have emerged as potential catalysts for the photodegradation of organic dyes from wastewater. Furthermore, the low toxicity, biocompatibility, and antibacterial activity of ZnO against various bacteria have led to the application of ZnO NPs as antibacterial agents. Thus, this review will focus on the application of Lamiaceae-mediated ZnO NPs for the photodegradation of organic dyes and antibacterial applications.

ZrO2-doped ZnO-PDMS nanocomposites as protective coatings for the stone materials

<p class="Abstract"><span lang="EN-US">ZnO is a semiconductor that has found wide application in the optics and electronics areas. Moreover, it is widely used in different technological areas </span><span lang="EN-US">due to its beneficial qualities (high chemical stability, non-toxicity, high photo-reactivity, and cheapness). Based on its antibacterial activity, recently it has found also application to prevent bio-deterioration of cultural heritage buildings. As many authors suggested, doped ZnO nano-structures exhibit better antibacterial properties than undoped analogues. In the present work, ZnO nanoparticles doped with ZrO<sub>2</sub> have been prepared by a sol-gel method in order to enhance the photocatalytic properties as well as the antibacterial activity of ZnO. Then, ZrO<sub>2</sub>-ZnO-PDMS nanocomposite (PDMS, polydimethylsiloxane used as the binder) was synthesized by in-situ reaction. The resulting nanocomposite has been investigated as a possible protective material for cultural heritage building substrates. The performances of newly prepared coating were evaluated in three different stones (Lecce stone, Carrara Marble and Brick) and compared with Plain PDMS as a reference coating. </span></p>

Designing and investigation of enhanced photocatalytic and antibacterial properties of 3d (Fe, Co, Ni, Mn and Cr) metal-doped zinc oxide nanoparticles

In the present study, transition metal (Fe, Cr, Ni, Co and Mn)-doped ZnO nanoparticles (TM-ZN NPs) were synthesized via the chemical co-precipitation method. The effect of TM doping on the photocatalytic and antibacterial activity of ZnO (ZN) nanoparticles has been studied. Important analytical techniques characterized the synthesized materials. The XRD analysis verified the TM doping in ZN and confirmed the wurtzite hexagonal structure of ZN and TM-ZN NPs. SEM and TEM studied the synthesized samples' morphology and size, and the compositional analysis was performed by EDX spectroscopy. TM-ZN NPs showed enhanced photocatalytic and antibacterial activity than ZN NPs. In particular, Mn-doped ZnO nanoparticles (MnZN NPs) exhibited the highest bactericidal efficiency against Gram-negative and Gram-positive strains and maximum MB photocatalytic degradation (98% in 120 min) under sunlight irradiations. The notable increase in the photocatalytic and antibacterial activity of the synthesized TM-ZN NPs might be attributed to a decrease in their bandgap and suppression of e-h pairs recombination due to the induction of additional energy levels below the CB of ZN. The MnZN NPs showed good photocatalytic stability even after six consecutive cycles. Furthermore, a conceivable bactericidal and MB degradation mechanism over the MnZN NPs has been suggested.

Syzygium Cumini leaf extract exploited in the green synthesis of zinc oxide nanoparticles for dye degradation and antimicrobial studies

Zinc oxide was prepared via green synthesis method. ZnO had high excitation energy (60 meV), ample energy band gap (3.37 eV), high thermal stability and mechanical stability. These properties made ZnO smart and it will be utilized in various fields like electronics, optoelectronics and laser technology, light emitting diodes (LEDs), photo detectors, solar cells, gas sensors, film transistors and biological applications. The structural and surface morphology were investigated using XRD, SEM, EDAX and UV–visible techniques. The antibacterial activity of ZnO had been evaluated. The results indicated that the sample was giving more effective for Klebsiella when compare with other bacterial organisms such as Pseudomonas, Enterococcus, Escherichia coli. The ZnO nanoparticles were synthesized via green method and analysed, and the enhancement of their catalytic properties against congo red dye under diverse experimental conditions. The maximum decolourisation for Congo red was found to be 90 %. ZnO had numerous applications in which some of applications were used in biomedical field like drug delivery, cancer therapy, anti-diabetic agent, anti bacterial, dye degradation.

Green Synthesis of ZnO Nanoparticles Using <i>Ca</i><i>esalpinia sappan</i> Leaf Extracts and its Antibacterial Activity on <i>Ralstonia solanacearum</i>

Abstract. Zinc oxide nanoparticles (ZnO NPs) are known to be one of the multifunctional inorganic nanoparticles with its application in the treatment of bacterial pathogens, especially when synthesized through green nanotechnology. In this study, ZnO NPs were successfully synthesized through co-precipitation method and its antibacterial activity against Ralstonia solanacearum was evaluated. Surface morphology through scanning electron microscope (SEM) exhibited an agglomerated rod-like structures, with a mean particle size of 180.9 nm. Phytochemical screening was performed through various chemical qualitative tests, to which the presence of terpenoids and cardiac glycosides in Caesalpinia sappan leaves was confirmed in the aqueous extract. Five treatments were evaluated against R. Solanacearum in terms of their zone of inhibition. The highest zone of inhibition from the different concentrations was observed from the positive control (Gentamicin) with a mean value of 34.47 mm, followed by 0.57 g/mL ZnO NPs with a mean value of 21.69 mm, and no zone of inhibition on the negative control, 0.28 g/mL, and 0.19 g/mL of synthesized ZnO NPs. Antibacterial activity of ZnO using disc diffusion method resulted in a significant zone of inhibition which proves that synthesized nanoparticles can be used as a potent antibacterial agent against R. solanacearum.

Microplasma-assisted electrochemical synthesis of ZnO nanostructures for photocatalytic and antibacterial applications

Zinc oxide nanostructures (ZnO NSs) have been extensively studied because of their many applications in different fields. In this study, an attempt has effectively been made for the synthesis of ZnO nanostructures by using fast and environment-friendly microplasma electrochemical technique. The prepared nanostructures were examined in terms of their morphological, optical, structural, electrical, and compositional properties by using different characterization techniques. Results demonstrated that the highly crystalline ZnO nanostructures were produced with a single hexagonal (wurtzite structure) phase. Results also indicated the crystallite size increases with increasing precursor concentration. The optical band gap of ZnO is found to decrease (from 3.48eV to 3.40 eV) with increasing crystallite size. I-V characteristics of ZnO are measured by two probe technique which shows semiconducting behavior of prepared ZnO. The antibacterial and photocatalytic properties of the synthesized nanostructures were also investigated. It was observed that the degradation efficiency of zinc oxide photocatalyst increases with the irradiation time. About 85% of Rhd B dye was degraded by ZnO after 120 min at a rate of 0.01339 min−1 under direct sunlight irradiation. The antibacterial activity of ZnO was carried out against different gram-positive and gram-negative bacterial strains, by using the diffusion well method. Higher antibacterial activities were observed against gram-negative bacteria as well as for a higher concentration of ZnO. This study will be helpful to synthesize low-cost and effective materials to remove microorganisms and toxic industrial organic dyes which is a serious threat to terrestrial and aquatic life.

Enzymatically-degradable hydrogel coatings on titanium for bacterial infection inhibition and enhanced soft tissue compatibility via a self-adaptive strategy

Ideal percutaneous titanium implants request both antibacterial ability and soft tissue compatibility. ZnO structure constructed on titanium has been widely proved to be helpful to combat pathogen contamination, but the biosafety of ZnO is always questioned. How to maintain the remarkable antibacterial ability of ZnO and efficiently reduce the corresponding toxicity is still challenging. Herein, a hybrid hydrogel coating was constructed on the fabricated ZnO structure of titanium, and the coating was proved to be enzymatically-degradable when bacteria exist. Then the antibacterial activity of ZnO was presented. When under the normal condition (no bacteria), the hydrogel coating was stable and tightly adhered to titanium. The toxicity of ZnO was reduced, and the viability of fibroblasts was largely improved. More importantly, the hydrogel coating provided a good buffer zone for cell ingrowth and soft tissue integration. The curbed Zn ion release was also proved to be useful to regulate fibroblast responses such as the expression of CTGF and COL-I. These results were also validated by in vivo studies. Therefore, this study proposed a valid self-adaptive strategy for ZnO improvement. Under different conditions, the sample could present different functions, and both the antibacterial ability and soft tissue compatibility were finely preserved.

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

AbstractZnO‐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.

Antibacterial activity of ZnO and CuO nanoparticles against gram positive and gram negative strains.

This is a report on the antibacterial activity of ZnO and CuO nanoparticles synthesized via sol-gel method. The studies were performed on Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli and Pseudomonas aeruginosa bacteria using disc and well diffusion methods, bioluminescence and optical density analysis. The results show a strong decline of bacterial strains after a short contact with nanoparticles. The modelling allowed clarifying the bacterial sensitivity of toxic agents at different stages of their population evolution kinetics. It was concluded that the bacterial suppression is most effective at the exponential growth phase while it is of a lower effectiveness at the lag and stationary phases. The CuO and ZnO nanoparticles showed comparable effectiveness at the exponential growth phase. In the same time, ZnO was almost inactive at the lag phase and of lower effectiveness at the stationary phase, at which CuO conserved a significant activity.

The influence of H2O2 on the antibacterial activity of ZnO

The size of microorganisms usually ranges from hundreds of nanometers to tens of micrometers. Zinc oxide nanoparticles (ZnO–NP) belongs to bio-safe material. And its antibacterial activity has attracted extensive attention because of various properties such as cost-effective benefits, UV-blocking properties and photooxidization. In this study, the effects of H2O2 on the antibacterial activity of zinc oxide were explored by using H2O2 as an auxiliary agent in the synthesis reaction of zinc oxide. The synthesis reaction of ZnO–NP was developed with H2O2 or without H2O2 treatment. And our results showed that zinc oxide with H2O2 treatment demonstrated the decreased antibacterial activity against both S. a and E. coli. when compared to that of zinc oxide without H2O2 treatment, which may be attributed to the observations: (1) the analysis of photocatalytic activity indicated that zinc oxide without H2O2 treatment generated more H2O2, and release more Zn2+ iron from ZnO than that of zinc oxide with H2O2 treatment; (2) the comparison of ZnO–NP morphology indicated that H2O2 treatment changed ZnO–NP from spherical-like microstructure to rod-like nanostructure when zinc oxide with H2O2 treatment was synthesized. These results support additional evidence for us to better understand the antibacterial mechanism of zinc oxide with or without H2O2 treatment, and offer a clue for us to develop zinc oxide with new properties for a wide range of applications by adding an auxiliary agent in the synthesis reaction of ZnO–NP.

Study on the antimicrobial mechanism of Ag/ZnO coating

Study on the antimicrobial of Ag/ZnO coating already become one of the research focuses in Antibacterial material business, which Ag and ZnO have Efficient, broad spectrum, safe, green antibacterial properties. But at present, different scholars have different views and understanding on the antibacterial properties and antibacterial mechanism of the antimicrobial of Ag/ZnO coating. In this paper, the recent research progress of antibacterial properties and antibacterial mechanism of the antimicrobial of Ag/ZnO coating at home and abroad in recent years were reviewed. In this paper, the antibacterial mechanism of the antimicrobial of Ag/ZnO coating was elaborated in detail from 4 aspects: the destruction of the integrity of bacterial cells, the blocking of bacterial ATP and DNA replication, the generation of reactive oxygen species and the unique photocatalytic antibacterial activity of ZnO. The author points out that the antimicrobial process of the antimicrobial of Ag/ZnO coating is affected by various mechanisms. It is concluded that the antibacterial process of the antimicrobial of Ag/ZnO coating is more complicated, study the mode of action of deeper Ag and ZnO antibacterial and antibacterial mechanism and the influential factors will be helpful to widely used the antimicrobial of Ag/ZnO coating. Key words: Antibacterial material; Silver bearing Zinc Oxide; Antibacterial property; Antibacterial mechanism

Structural, morphological, optical and biological properties of pure ZnO and agar/zinc oxide nanocomposites

In this work, ZnO nanoparticles were prepared by in situ chemical precipitation method in the presence of Agar biopolymer. The influence of Agar concentrations on the structural, morphological and optical properties of ZnO have been investigated. The XRD pattern of Pure ZnO and Agar/ZnO nanocomposites indicates the hexagonal wurtzite phase of ZnO. The crystallite size of pure ZnO and Agar/ZnO nanocomposites was found to be in the range of 35.5 to 19.73 nm. Pure ZnO and Agar/ZnO nanocomposites showed nanospheroid and nanopaddy shaped morphology from FESEM studies. The interplanar distance observed from the HRTEM image confirms the plane of the prepared material. The elemental composition of the samples were characterized by EDX. The optical properties of Pure ZnO and Agar/ZnO nanocomposites were characterized by UV, FTIR and PL. The band gap of Agar/ZnO nanocomposites were varied with the Agar concentration. Oxygen vacancy induced photoluminescence of ZnO are observed and its intensity is found to be increased linearly with the Agar concentration. The antibacterial activity of ZnO and Agar/ZnO nanocomposites was evaluated by disc diffusion method against Gram-positive (B.subtilis) and Gram-negative (P. aeruginosa) bacteria. The cytotoxicity of Agar/ZnO nanocomposites was studied against Normal (L929) and Breast cancer cell line (MB231). The result of this investigation reveals that the Agar/ZnO nanocomposites deliver a dose dependent toxicity in normal and cancer cell line.

Deposition of Zinc Oxide on Different Polymer Textiles and Their Antibacterial Properties.

A surface modification of polyamide 6 (PA), polyethylene terephthalate (PET) and polypropylene (PP) textiles was performed using zinc oxide to obtain antibacterial layer. ZnO microrods were synthesized on ZnO nanoparticles (NPs) as a nucleus centers by chemical bath deposition (CBD) process. Scanning Electron Microscopy (SEM) and X-ray diffraction (XRD) indicated that wurzite ZnO microrods were obtained on every sample. Differential Scanning Calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FTIR), Atomic Force Microscopy (AFM) and Liquid Absorption Capacity (LAC) analysis indicate that the amount and structure of antibacterial layer is dependent on roughness and wettability of textile surface. The rougher and more hydrophilic is the material, the more ZnO were deposited. All studied textiles show significant bactericidal activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). A possible mechanism and difference in sensitivity between Gram-negative and Gram-positive bacteria to ZnO is discussed. Considering that antibacterial activity of ZnO is caused by Reactive Oxygen Species (ROS) generation, an influence of surface to volume ratio and crystalline parameters is also discussed.

SYNTHESIS OF ZINC OXIDE/GRAPHENE OXIDE NANOCOMPOSITES AS ANTIBACTERIAL MATERIALS AGAINST STAPHYLOCOCCUS AUREUS AND ESCHERICHIA COLI

New materials with good antibacterial activity and less toxicity to other species have attracted numerous research interests. Modified Hummers method was used for preparing graphene oxide (GO). Zinc oxide/graphene oxide (ZnO/GO) nanocomposites were synthesized with three different ratios (0.5:1, 1:1, and 2:1) by solution precipitation method. The ZnO/GO nanocomposites were characterized by Fourier transform infrared spectroscopy, X–ray diffraction, Raman spectroscopy, Brunauer–Emmett–Tellerspecific surface area, and transmission electron microscopy image. The characterization results showed that ZnO nanoparticles with a mean size of 12–18 nm were randomly decorated on the surfaces and edges of GO sheets. ZnO/GO 1:1 with a high specific surface area of 65 m2/g was obtained. The antibacterial activity of ZnO, GO, and ZnO/GO was tested against Gram negative bacteria escherichia coli (E. coli) and Gram positive bacteria staphylococcus aureus (S. aureus) using well diffusion method. The test results confirmed that antibacterial activity of ZnO/GO was higher than that of GO and ZnO. Additionally, the ZnO/GO with the ratio of 1:1 is the strongest activity and more active against S. aureus than against E. coli and minimal inhibitory concentration (MIC) value of ZnO/GO 1:1 is 80 µg/mL for S. aureus and 160 µg/mL for E. coli. This novel nanocomposite could be used as a potential material for antimicrobial application.

Chemical manipulation of oxygen vacancy and antibacterial activity in ZnO

Pure and doped ZnO (cation and anion doping) compositions have been designed in order to manipulate oxygen vacancy and antibacterial activity of ZnO. In this connection, we have synthesized and characterized micron sized ZnO, N doped micron sized ZnO, nano ZnO, nano Na and La doped ZnO. The intrinsic vacancies in pure ZnO and the vacancies created by N and Na doping in ZnO have been confirmed by X-ray Photoelectron Spectroscopy(XPS) and Photoluminiscence Spectroscopy(PL). Reactive oxygen species (ROS) such as hydroxyl radicals, superoxide radicals and H2O2 responsible for antibacterial activity have been estimated by PL, UV–Vis spectroscopy and KMnO4 titrations respectively. It was found that nano Na doped ZnO releases highest amount of ROS followed by nano ZnO, micron N doped ZnO while micron ZnO releases the least amount of ROS. The concentration of vacancies follows the same sequence. This illustrates directly the correlation between ROS and oxygen vacancy in well designed pure and doped ZnO. For the first time, material design in terms of cation doping and anion doping to tune oxygen vacancies has been carried out. Interaction energy (Eg), between the bacteria and nanoparticles has been calculated based on Extended Derjaguin-Landau-Verwey-Overbeek (EDLVO) theory and is correlated with antibacterial activity.

Soft jet plasma-assisted synthesis of Zinc oxide nanomaterials: Morphology controls and antibacterial activity of ZnO

This manuscript discusses about size and shape-selective preparation of Zinc oxide nanomaterials (ZnO NMs) using simple and handy soft jet plasma source. The soft jet was operated in an atmospheric pressure with low energy consumption and utilized ambient air as a feed gas. The plasma synthesized ZnO NMs exhibited variety of surface morphology such as nanorods, nanosheets and micro-size flowers as compared to the conventional low temperature synthesized powders which showed spherical shape. The precursor concentrations and kinds of precursors were strongly influenced into the NMs morphology and possible growth mechanism in the presence of plasma has been proposed. It is suggested here that the soft jet plasma is an effective tool to control size and shape of ZnO NMs especially when the preparations demanding low temperature, surfactant free and cost-effective synthesis. The prepared ZnO NMs were tested for its shape dependent anti-bacterial property against Gram-positive bacteria namely S. iniae and S. parauberis and two Gram-negative bacteria such as E. coli and V. anguillarum. The flower-like ZnO NMs showed more powerful anti-bacterial activity than rod or sheet-like ZnO structures.

In vitro antimicrobial activity of ZnO based glass-ceramics against pathogenic bacteria.

The antibacterial activity of ZnO (0-15.53 mol%) based SiO2-CaO-P2O5-Na2O-CaF2 bioactive glass-ceramics synthesized by controlled crystallisation were studied against eight micro-organisms using modified Kirby Bauer method. The antibacterial activity of the specimens was statistically evaluated using one-way analysis of variance and P < 0.05 was used as the level of significance. In vitro dissolution tests were performed in stimulated body fluid for 48 h at 37 °C for different time intervals to correlate the dissolution behaviour of test samples with antibacterial effects. The results illustrate that specimen BZn15.53 having the highest concentration of ZnO (15.53 mol%) demonstrated the strongest effect against Staph.aureus, S. epidermidis, B. subtilis and K. pneumonia. The effectiveness of BZn15.53 in inhibiting bacteria was due to accumulation of Zn(+2) ions around the surface of the bacteria cell release that caused the death of the cell, besides the presence of hydroxyapatite phase was also responsible for damaging the cell membrane of bacteria.

Effect of Mg doping level on the antibacterial activity of (Mg + F)-doped ZnO nanopowders synthesized using a soft chemical route

ZnO nanopowders simultaneously doped with fluorine (20 at.%) and magnesium (4, 8, 12 and 16 at.%) (ZnO:F:Mg) have been synthesized using an inexpensive simple soft chemical route for the first time. The effect of Mg doping level on certain physical properties and antibacterial activities of ZnO:F:Mg nanopowders has been investigated and reported. XRD studies showed that the products have the hexagonal wurtzite structure of ZnO. Fourier transform infrared spectra authenticate the presence of MgO stretching vibration, which is responsible for the increased antibacterial activity of the synthesized samples. The antibacterial activity of ZnO:F:Mg nanopowders was found to be enhanced with increase in Mg doping level as it causes a reduction in the grain size.

Is the effect of surface modifying molecules on antibacterial activity universal for a given material?

Antibacterial activity of nanomaterials is strongly dependent on their properties, and their stability and toxicity can be varied using surface coatings. We investigated the effect of different surface modifying molecules on the antibacterial properties of two ZnO nanoparticle samples. We found that the starting surface properties of the nanoparticles have significant effects on the attachment of the surface modifying molecules and consequent antibacterial activity. Two out of five investigated surface modifying molecules not only had a significant difference in the magnitude of their effect on different nanoparticles, but also resulted in the opposite effects on two ZnO nanoparticle samples (an enhancement of antibacterial activity for one and a reduction of antibacterial activity for the other ZnO sample). This indicates that no general rule on the effect of a specific molecule on the toxicity of a metal oxide nanoparticle can be derived without knowing the nanoparticle properties, due to the fact that surface modifier attachment onto the surface is affected by the initial surface properties.