Antibacterial Activity Of ZnO Nanoparticles Research Articles

Influence of Nickel concentration on the photocatalytic dye degradation (methylene blue and reactive red 120) and antibacterial activity of ZnO nanoparticles

This study assessed the synergistic effect of Ni concentration and ultrasonic assisted process on the photocatalytic dye degradation efficiency towards methylene blue (MB) and reactive red 120 (RR120) and antibacterial activity against various bacteria of ZnO nanoparticles. XRD confirms the absence of any other impurity peaks in Nickel (Ni) doped ZnO nanoparticles, disclose that Ni doping influences the lattice structure of Zn. The obvious red-shift with the increase of Ni concentration results in decreased band gap and transmittance. SEM micrograph confirms the formation of hexagonal rod and sheet like nanostructures in the Ni doped ZnO nanoparticles by the ultrasonic assisted co-precipitation method. The Ni doped ZnO nanoparticles control the recombination of charge carriers and increase the photocatalytic degradation of MB and RR120. The antibacterial result revealed that 5% Ni substituted sample is effective as an antibacterial agent to prevent the bacterial contamination. 5% Ni doped ZnO nanoparticles synthesized by ultrasonic assisted coprecipitation method is an excellent candidate for removal of methylene blue and bacteria.

Biosynthesis and Antibacterial Activity of ZnO Nanoparticles by Artemisia aucheri Extract.

Background: Green approach to nanoparticles, including metal oxides Because of an inevitable disadvantage of physical or chemical synthesis routes is attractive nowadays. ZnO nanoparticles play a key role in the medicals and drugs area.Objectives: In this study, biosynthesis of ZnO nanoparticles with new approach to enhanced the Antimicrobial properties against gram-negative and gram-positive was performed by use of a new type of plant extract, Artemisia aucheri, in an environmentally friendly, cost-effective, simple procedure way.Materials and Methods: By adding Zn(NO3)2 to A. aucheri methanol extract followed by stirring The resulted solution and final heat treatment in 200 °C the ZnO nanoparticles were synthesized. Disc diffusion method was applied to evaluation the Antimicrobial properties of the extract and nanoparticles towards resistance into Escherichia coli (gram-negative) and Staphylococcus aureus (gram-positive).Results: X-ray diffraction pattern (XRD) result showed all of the peaks proportion to ZnO and no other peaks were detected, also demonstrated nanostructure nature with crystallite size about 9 nm. In the Fourier transform infrared spectroscopy (FTIR), there is a band in the 550 cm-1 which is corresponded to ZnO. Also 76 nm average particle size obtained by DLS experiments. Energy-dispersive X-ray spectroscopy (EDS) analysis showed strong peaks for Zn and O, support supposition of ZnO nanoparticles. Field emission scanning electron microscopy (FESEM) images indicated spherical rounded particles with the size of average 30 nm. Antibacterial tests showed effective diameter about 11 and 10 mm for plant extract and also 7 and 5 mm for ZnO nanoparticles against E. coli (gram-negative) and S. aureus (gram-positive) in agar disc diffusion method, respectively. Conclusions: Biosynthesized ZnO nanoparticles could be a good candidate for antibacterial activity, both against E. coli (gram-negative) and S. aureus (gram-positive) especially for versus E. coli.

Biosynthesis of ZnO nanoparticles through extract from Prosopis juliflora plant leaf: Antibacterial activities and a new approach by rust-induced photocatalysis

Rust-induced photocatalytic and antibacterial activities of ZnO nanoparticles derived from Prosopis juliflora leaf extracts by biosynthesis using the hydrothermal method at 170 °C are reported in this study. The characterization has been accomplished by various methods such as XRD, DRS, FT-IR, SEM, TEM, EDAX, and PL spectra. XRD exhibits that ZnO has a hexagonal wurtzite structure with a preferred orientation of 101 planes. The functional groups, which are present in the leaf extracts, are responsible for corresponding peaks in FT-IR spectra. The FESEM images of the synthesized nanoparticles show the morphology sphere like structure. ZnO particle size of 65 nm has been observed from HR-TEM analysis. The elemental composition has a good agreement with the biosynthesized ZnO nanoparticles. The antibacterial activities have been carried out in vitro assays against four different pathogens viz Escherichia coli (E. coli), Rhodococcus rhodochrous (R. rhodochrous), Bacillus subtilis (B. subtilis) and Vibrio cholera (V. Cholera) against a standard (streptomycin sulfate). Furthermore, the Photocatalytic ability of the titled nanoparticles has been experimented from the rust solution with methylene blue and degradation under UV radiation of 99%. The proposed mechanism is based on scavenger studies and it is investigated during the photo degradation of Methylene blue. The catalytic amount and recovery of photocatalyst have also been studied in detail.

Impact of the changes in bacterial outer membrane structure on the anti-bacterial activity of zinc oxide nanoparticles.

Metal and metal oxide nanoparticles (NPs) have been increasingly utilized in many industries to harness their documented antibacterial properties. However, the mechanism(s) of action is still debated in the literature. The aim of this study is to understand how changes in outer membrane charge of a test bacteria Haemophilus influenzae alter the antibacterial activity of ZnO NPs of average sizes of 20 nM and 60 nM. H. influenzae outer membrane charge was altered through use of the wild strain (Rd) and mutant lines H543 and H446. Results indicate that antibacterial effects are both concentration and size dependent, with smaller NPs causing increased antibacterial response. Most critically, antibacterial assays and collected TEM images demonstrate that increasing negative charge on the outer membrane of bacteria decreased the antibacterial activity of the ZnO NPs. Finally, this work demonstrates the possibility of using ZnO NPs to treat H. influenzae infection in clinical settings.

Facile green synthesis of zinc oxide nanoparticles (ZnO NPs): antibacterial and photocatalytic activities

The objective of this study was carried out to exhibit a novel, cost-effective, non-toxic and green way to prepare ZnO nanoparticles (NPs) using Laurus nobilis plant extract as both reducing and capping agents without any hazardous material. X-ray diffraction analysis also confirmed that the synthesized NPs has Wurtzite hexagonal structure with an average crystalline size between 20 and 35 nm. The extract was found to contain reducing components such as polyphenols (22.5%) and flavonoids (21%). The ZnO NPs was characterized by a peak 375 nm in the UV- Vis spectrum. In addition, FTIR results provided the presence of both, leaf extract and ZnO NPs. The antibacterial activity of ZnO NPs was investigated against Escherichia coli using an agar dilution method. The minimal inhibitory concentration value of the ZnO nanoparticles was found to be 1200 μg ml−1 for E. coli. As a result, the biosynthesized ZnO NPs indicated a great promise for applications in a large area of biomedical applications as a kind of antibacterial material. The biosynthesized ZnO NPs also conducted successful photocatalytic activity as much as commercial ZnO powders under the UV light using the textile dye, Remazol Brilliant Red F3B (Reactive Red 180 (RR180)) solutions. We found an excellent degradation percentage (99%) within a short time (60 min). Plant extract was suggested as an essential bioresource of producing ZnO NPs.

Investigation on Bovine Serum Albumin (BSA) binding efficiency and antibacterial activity of ZnO nanoparticles

Biomolecule-NPs interaction is extremely important in various biomedical applications especially for assessing the macrostructural effects of nanoparticles on proteins. We prepared ZnO nanoparticles (ZnO NPs) of average dimension, ~11 nm, using citrus lemon extract assisted green synthetic strategy. The binding interaction with Bovine Serum Albumin (BSA) was monitored from changes in inherent fluorescent emission characteristics of BSA and synchronized emission spectra of component fluorophores in presence of ZnO NPs.Molecular docking studies conducted to analyse the binding sites and associated parameters. Here in the sample possess very strong interaction with BSA. Comparison of binding constant with similar studies indicates the superior performance of ZnO NPs developed using lemon fruit extract. Molecular docking studies disclosed the mode of interactions and the negative value of binding models indicates a worthy and feasible interaction. Antibacterial activity of ZnO NPs was tested against K. pneumoniae, S. aureus, E. coli and P. mirabilis bacterial pathogens. The zone of inhibition and minimum inhibitory concentration and minimum bactericidal concentrations were also determined. The developed ZnO NPs exhibits antibacterial activity against the studied pathogens.

Origin of Antibacterial Activity of ZnO Nanoparticles: The Roles of Protonic and Electronic Conductions

AbstractTo elucidate the origin of antibacterial activity of ZnO nanoparticles, a reactive oxygen species (ROS) mechanism is systematically investigated based on electronic and protonic conductions. While the enhancement of antibacterial activity by an increase in electronic conductivity is marginal, an apparent improvement is observed by in the increase of protonic conductivity in terms of the surface basicity. This study first demonstrates that antibacterial activity can be enhanced by controlling the surface basicity of solid particles. The basicity of ZnO can be modulated by doping alkaline‐earth oxides such as MgO and CaO, and it results in the increase of hydroxyl defects on the surface of solid particles. The basicity shows a strong dependency on mobile OH concentrations. The increase of ROS hydroxyl radicals is confirmed by Mg (ZMO) or Ca‐doping (ZCO), which shows high antibacterial activity, and Ca‐doped ZnO exhibits the highest performance. It is clearly observed that the antibacterial activity is proportional to the basicity, which is controlled by the mobile OH formation. While both electrons and hydroxyl species are required for ROS reactions, it is concluded that the formation of hydroxyl species is a key factor in improving the antibacterial activity in ZnO.

Antibacterial activity of ZnO nanoparticles fabricated using laser ablation in solution technique

The zinc oxide (ZnO) nanoparticles have been produced by using laser ablation in solution technique, resulting nanoparticles with hexagonal wurtzite structure and the size range of 20 – 50 nm. The optical characterization has predicted the nanoparticles band gap at least 3.16 eV. The ZnO nanoparticles were employed as an antibacterial agent for the growth of Escherichia coli (E. coli), and it shows a great potential. Total plate count (TPC) analysis was conducted by applying the ZnO nanoparticles with different concentration of 5%, 10%, 15%, 20%, 25% and 30% (portion of bacteria medium). The 5% concentration could reduce more than half of the E. coli population after 24 hours incubation time. There was no living bacteria detected for 20%, 25% and 30% ZnO concentration.

Hydrothermally synthesized Cd-doped ZnO nanostructures with efficient sunlight-driven photocatalytic and antibacterial activity

The doping in the metal oxide is key factors that can affect the photocatalytic and antibacterial activity. In present work, Cd-doped ZnO nanostructures have been synthesized by using a facile hydrothermal method. The sunlight induced photocatalytic activity of Cd-doped ZnO nanostructures was evaluated towards the degradation of methylene blue dye. The antibacterial activity of ZnO nanoparticles against Staphylococcus aureus was investigated. The XRD patterns exhibit a wurtzite hexagonal crystal structure with crystallite size in the range of 18–23 nm. Field emission scanning electron microscopy revealed the plate-like morphology of undoped ZnO and it transforms into small nanorods and aggregated irregularly shaped nanoparticles with the incorporation of Cd into ZnO. Energy dispersive spectroscopy analysis confirms the presence of cadmium in Cd-doped ZnO sample. The UV–Visible absorption spectra showed a redshift with an increase in Cd dopant concentration in ZnO. The PL spectra show near band edge emission and defect-related visible emission band. The Cd-doped ZnO exhibits excellent photocatalytic degradation of methylene blue dye compared to undoped ZnO within 30 min. The Cd-doped ZnO (4 wt%) shows maximum photocatalytic degradation efficiency of 84% under sunlight irradiation.

Synthesis, characterization of nanocrystalline ZnO via two different chemical methods and its antibacterial activity

We investigated anti-bacterial activity of nanocrystalline ZnO samples were prepared by two different chemical methods such as precipitation and disperser-assisted sonochemical without use of any surface modifying agents. The nanoparticles, prepared by both the methods were characterized by infrared spectroscopy, X-ray diffraction, field emission-scanning electron microscopy coupled with energy dispersive X-ray analysis, thermogravimetric analysis, UV-visible spectroscopy and transmission electron microscopy. The characterization results indicates, that the presence of ZnO in nanocrystalline nature. Inhibition zone test were performed to examine the antibacterial activity of ZnO nanoparticles against bacteria Staphylococcus Aureus, Klebsiella pneumoniae and Escherichia coli in vitro. Obviously, overall the experimental results suggest that prepared ZnO nanoparticles by disperser-assisted sonochemical with flower-like morphology showed better anti-bacterial activity against other ones due to presence of ZnO with smaller crystal size and larger surface area.

Biosynthesis of zinc oxide nanoparticles by using fruits extracts of Ananas Comosus and its antibacterial activity

Biosynthesis of metallic nanoparticles using plants, enzymes, and microorganism have been known as eco-friendly alternatives to conventional physical and chemical methods. Recently, the biological synthesis of nanoparticles has been a keen interest amongst researchers and scientist due to its simple technique, eco-friendliness, non-toxic, inexpensive and potential to perform in antibacterial activity. Thus, in this current work, the synthesis of zinc oxide (ZnO) nanoparticles using reduction agent from fruit extracts of Ananas Comosus is reported. The biosynthesized zinc oxide was characterized using Field Emission Scanning Electron Microscope (FESEM) with Energy Dispersive X-ray analysis (EDX), UV-Vis absorption spectroscopy and X-ray diffraction (XRD). The average size of the nanoparticles was found to be in the range of 30-57nm. The antibacterial activity of ZnO nanoparticles was carried out via agar diffusion method against pathogenic organisms. It is observed that the biosynthesized ZnO in the process has the efficient antibacterial activity. In conclusion, the green synthesis of zinc oxide nanoparticles using the fruit extract of Ananas Comosus is considered as a potential additive to substitute other metal oxides such as silver (Ag) and titanium dioxide (TiO2)but also provide antibacterial effect that able to enhance the nanoparticle performance.

The Campylobacter fetus S layer provides resistance to photoactivated zinc oxide nanoparticles.

The antimicrobial activity of metal-based compounds, including metal oxides, has resulted in numerous agricultural, industrial, and medical applications. Zinc oxide nanoparticles are toxic to Gram-positive and Gram-negative bacteria as well as to some fungi. In this study we assess the sensitivity of Campylobacter fetus, a Gram-negative bacterial pathogen of humans and animals, to ZnO nanoparticles and determine whether the S layer protects C. fetus from the antibacterial action of these nanoparticles. Broth and agar dilution assays revealed that ZnO nanoparticles at 100 μg/mL were bacteriocidal for C. fetus. Resazurin reduction assays confirmed the absence of metabolic activity, indicating that C. fetus cells had not entered into a viable but nonculturable state. Photoactivation of ZnO nanoparticles greatly enhanced their antibacterial activity, as evidenced by minimum bacteriocidal concentration (MBC) values decreasing to 16-62.5 μg/mL as a function of strain. MBC assays completed in the presence and absence of catalase revealed that H2O2, a product of ZnO nanoparticle photoactivation, contributed to C. fetus but not to C. jejuni cell death. S-layer-expressing C. fetus strains were more resistant to H2O2-mediated cell killing than were isogenic S-layer-deficient strains. These data indicate that C. fetus is sensitive to the antibacterial activity of ZnO nanoparticles and that the C. fetus S layer imparts protection against photoactivated nanoparticles.

Photocatalytic antibacterial application of zinc oxide nanoparticles and self-assembled networks under dual UV irradiation for enhanced disinfection.

BackgroundZinc oxide (ZnO) nanoparticles and their networks have been developed for use in various applications such as gas sensors and semiconductors.AimIn this study, their antibacterial activity against Escherichia coli under dual ultraviolet (UV) irradiation for disinfection was investigated.Materials and methodsZnO nanoparticles were synthesized and immobilized onto silicon (Si) wafers by self-assembly. The physicochemical properties and antibacterial activity of ZnO nanoparticles and their networks were evaluated. Gene ontology was analyzed and toxicity levels were also monitored.ResultsSynthesized ZnO nanoparticles were spherical nanocrystals (<100 nm; Zn, 47%; O, 53%) that formed macro–mesoporous three-dimensional nanostructures on Si wafers in a concentration-dependent manner. ZnO nanoparticles and their networks on Si wafers had an excellent antibacterial activity against E. coli under dual UV irradiation (>3log CFU/mL). Specifically, arrayed ZnO nanoparticle networks showed superior activity compared with free synthesized ZnO nanoparticles. Oxidative stress-responsive proteins in E. coli were identified and categorized, which indicated antibacterial activity. Synthesized ZnO nanoparticles were less cytotoxic in HaCaT with an IC50 of 6.632 mg/mL, but phototoxic in Balb/c 3T3.ConclusionThe results suggested that ZnO nanoparticles and their networks can be promising photocatalytic antibiotics for use in next-generation disinfection systems. Their application could also be extended to industrial and clinical use as effective and safe photocatalytic antibiotics.

Increased antibacterial activity of ZnO nanoparticles: Influence of size and surface modification.

In the current study, the size and surface of ZnO nanoparticle (ZnO NP) suspensions and powders were finely controlled to evaluate their influence on the ZnO antibacterial activity against Staphylococcus aureus and Escherichia coli. The ZnO NP were prepared by the sol-gel method with different reaction times for NP size control and followed by the addition of (3-glycidyloxypropyl) trimethoxysilane (GPTMS) as a surface modifier. The ZnO NP were characterized by different techniques and the antibacterial activity was assessed through the minimum inhibitory concentration assay (MIC), minimum bactericidal concentration assay (MBC) and scanning electron microscopy (SEM). The ZnO NP exhibited significant antibacterial activity against Staphylococcus aureus. The NP size highly influenced the antibacterial activity, which increased with decreasing particle size. The small ZnO NP presented bactericidal activity whereas the largest showed bacteriostatic activity. The use of GPTMS, in general, led to increase of MIC and MBC. The formation of holes in the cell wall of Staphylococcus aureus was evidenced by SEM after contact between the bacteria and ZnO NP. The cytotoxicity assay showed that ZnO NP did not cause a loss of cell viability in the human keratinocyte cell line (HaCat) at the maximum concentration assessed. Thus, this study indicated that 5 nm ZnO NP modified by GPTMS has great potential for use as an inorganic antibacterial material.

Novel synthesis, structural, optical properties and antibacterial activity of ZnO nanoparticles

The influence of precursor and solvent type on the structural and optical properties of ZnO nanoparticles synthesized through co-precipitation technique was investigated. The phase formation of the samples was studied by x-ray diffraction which confirmed single phase hexagonal wurtzite nature of the samples. X-ray profiles showed that the particle size of the synthesized samples decreases with changing the precursor and solvent. The high-resolution transmission electron microscopy (HR-TEM) confirms nanoparticles with an average crystallite size 13–32 nm with different precursors and solvents. The energy-dispersive x-ray analysis showed purity of samples as no unwanted element was traced in the prepared nanomaterials. The energy gap determined by fluorescence depends on the type of the solvent and precursor, and its values were reordered in the range 3.33–3.62 eV. For studying the thermal stability of the synthesized ZnO nanoparticles, a thermal analysis was carried out using thermogravimetric and the differential scanning calorimetry. For antibacterial activity, the synthesized ZnO nanoparticles are strongly antimicrobial as they successfully inhibited the growth of the tested micro-organisms.

Antibacterial activity of ZnO nanoparticles: dependence on particle size, dispersion media and storage time

Zinc oxide nanoparticles have a high potential as novel antimicrobial products. In this study ZnO nanoparticles of various sizes: 20-100 nm (ZnO-1) and 50-300 nm (ZnO-2) have been examined. This paper presents the results of an integrated study of the influence of physicochemical properties such as particle size and concentration of the freshly prepared and 24-hour suspensions of ZnO nanoparticles (0. 001…1000 mg/L) in distilled water and in normal saline upon their toxicity against bacteria E. coli. Ionic solutions of ZnCl2 were used for comparison study. Fresh aqueous solutions of nanoparticles displayed the highest antibacterial effect (E. coli survival under 5 − 25%). Storage for 24 hours reduced the toxicity of all the samples. In normal saline solutions the toxicity of the studied nanoparticles decreased at concentrations below 10 g/L. In all cases ZnO-2 suspensions displayed lower toxicity levels, especially after ageing for 24 hours. Stability analysis showed that the highest antibacterial effect was produced by less stable solutions containing the largest aggregates. Thus, it has been shown that antibacterial effects of zinc oxide nanoparticles are affected by the size of particles and their aggregates in colloidal solutions, chemical composition of the media and the suspensions storage time. The obtained results can be used for creating new types of antibacterial products including phytoprotectors based on nano-sized zinc oxide particles as well as for development of methods to assess and predict toxicity of zinc-containing suspensions.

A comprehensive study on antidiabetic and antibacterial activities of ZnO nanoparticles biosynthesized using Silybum marianum L seed extract

Green synthesis of ZnO nanoparticles (NPs) using the plants' extract and their potential application have driven a tremendous interest in recent years. This study reports a green microwave-assisted method for synthesis of ZnO NPs using Silybum marianum L. seed extract. Characteristics of the as-prepared sample was explored in terms of crystalline phase, morphology, composition, surface area, optical, and thermal properties. The particles of the biosynthesized sample (ZnO/extract) had smaller sizes than the chemically produced one (ZnO). The existence of biomolecules from Silybum marianum L seed extract linked to the ZnO/extract sample was approved by various analyses. The ZnO/extract sample was used for treating alloxan-induced diabetic rats and its efficiency was compared with ZnO, extract, and insulin treatments. For this purpose, the levels of blood glucose, insulin, total cholesterol, total triglyceride, and high-density lipoprotein were measured before and after treating with the studied treatment agents and compared with each other. Moreover, the antibacterial activities of both ZnO samples were investigated against E. coli to assess their potential antibacterial application. From the results, ZnO/extract NPs represented an outstanding performance in overcoming the diabetic disorders and good antibacterial activity against the studied bacteria.

Towards understanding the enhancement of antibacterial activity in manganese doped ZnO nanoparticles

In this work we focus on enhancing the antibacterial activity of ZnO nanoparticles by Mn doping, synthesized using a wet-chemical method. The as-obtained precursor powders were deeply investigated by thermal analyses correlated with the evolved gas analysis (TG-DTA-FT-IR) and by in situ high-temperature XRD to elucidate the thermally induced processes and to understand the manganese doped ZnO nanoparticles formation. The hexagonal wurtzite-type structure and the morphological characteristics of the thermally treated samples have been investigated by X-ray diffraction, and HRTEM. An average particle size ranging between 10 and 29 nm and a polyhedral and spherical morphology with a tendency to form aggregates were evidenced by TEM images. Optical absorption measurements reveal that the band gap of ZnO decreased from 3.19 to 2.99 eV, which confirmed the existence of Zn-O-Mn interaction. The incorporation of the Mn ions into the ZnO lattice has been studied by EPR spectroscopy and also, the generation of reactive oxygen species (ROS) has been evidenced by using the EPR coupled with the spin trapping probe technique. Here, we report that in addition to altering the crystallite size, morphology and optical absorption characteristics of ZnO, the introduction of Mn dopant also improves the antibacterial efficiency against pathogenic microorganisms, namely Escherichia coli and Bacillus cereus.

Synthesis of ZnO nanoparticles with chitosan as stabilizing agent and their antibacterial properties against Gram-positive and Gram-negative bacteria

Antibacterial activity of zinc oxide (ZnO) nanoparticles have received significant interest, particularly by the implementation of nanotechnology to synthesize particles in nanometer region. ZnO nanoparticles were successfully synthesized through microwave heating by using chitosan as a stabilizing agent and characterized by UV–vis, FTIR, XRD and FESEM-EDX. The aim of the present study is to determine the antibacterial activity of ZnO nanoparticles against Gram-positive bacterium Staphylococcus aureus (S. aureus) and Gram-negative bacterium Escherichia coli (E. coli). The antibacterial effect of ZnO nanoparticles was investigated for the inhibition zone and inactivation of cell growth. The absorption of ZnO nanoparticles was found to be around 360 nm. FTIR results showed the stretching mode of ZnO nanoparticles at 475 cm−1 of the absorption band. EDX results indicated that ZnO nanoparticles have been successfully formed with an atomic percentage of zinc and oxygen at 23.61 and 46.57% respectively. X-ray diffraction result was confirmed the single-phase formation of ZnO nanoparticles and the particle sizes were observed to be around 50 to 130 nm. The results showed that ZnO nanoparticles have displayed inhibition zone of 16 and 13 mm against S. aureus and E. coli respectively. Gram-negative bacteria seemed to be more resistant to ZnO nanoparticles than Gram-positive bacteria.

Effect of Zinc Oxide Nanoparticles on Staphylococcus AureusIsolated From CowsʼMastitic Milk

The current spreading of nanomaterial applications supports the search for further possible functions of theses diminutive particles. The antibacterial potentiality of zinc oxide (ZnO) nanoparticles (NPs) againstS. aureus causing mastitis was evaluated using qualitative and quantitative assays. These tests were performed in nutrient broth and nutrient agar following standard methods. In addition, the effect of different concentrations of ZnO nanoparticles on the growth of S. aureus was measured.MIC was determined using six different concentrations of ZnO nanoparticles including 16, 8, 4, 2, 1 and 0.5 mg/ml. The MIC value S. aureus was 0.5 mg/ml. The results showed that ZnO nanoparticles have antibacterial inhibition zone of 29 mm at the concentration of 10 mg/ml against S. aureus., and the antibacterial activity of ZnO nanoparticles increased with increasing powder concentration in vitro.