Antibacterial Activity Of Zinc Oxide Research Articles

Enhancement of Antibacterial Properties, Surface Morphology and In Vitro Bioactivity of Hydroxyapatite-Zinc Oxide Nanocomposite Coating by Electrophoretic Deposition Technique

To develop medical-grade stainless-steel 316L implants that are biocompatible, non-toxic and antibacterial, such implants need to be coated with biomaterials to meet the current demanding properties of biomedical materials. Hydroxyapatite (HA) is commonly used as a bone implant coating due to its excellent biocompatible properties. Zinc oxide (ZnO) nanoparticles are added to HA to increase its antibacterial and cohesion properties. The specimens were made of a stainless-steel grade 316 substrate coated with HA-ZnO using the electrophoretic deposition technique (EPD), and were subsequently characterized using scanning electron microscopy (SEM), energy dispersive X-ray (EDX), stylus profilometry, electrochemical corrosion testing and Fourier transform infrared (FTIR) spectroscopy. Additionally, cross-hatch tests, cell viability assays, antibacterial assessment and in vitro activity tests in simulated body fluid (SBF) were performed. The results showed that the HA-ZnO coating was uniform and resistant to corrosion in an acceptable range. FTIR confirmed the presence of HA-ZnO compositions, and the in vitro response and adhesion were in accordance with standard requirements for biomedical materials. Cell viability confirmed the viability of cells in an acceptable range (>70%). In addition, the antibacterial activity of ZnO was confirmed on Staphylococcus aureus. Thus, the HA-ZnO samples are recommended for biomedical applications.

Zinc Oxide Nanoparticles as The Anti-Bacterial Tool: In Vitro Study

A new class of metal oxide nanoparticles has recently been found to be widely used in various health-related research. In particular, Zinc Oxide (ZnO) nanoparticles have occupied a prominent status due to their unique chemical and electrical properties. In our study, we aim to reveal the anti-bacterial effect of these nanoparticles. The antibacterial activity of zinc oxide (ZnO) nanoparticles against isolated pathogenic Escherichia coli (strain MTCC 723) was determined from our study. The antimicrobial properties of ZnO were also determined by adjusting the concentration of ZnO nanoparticles. By sonicating ZnO nanoparticles in water, a homogenized suspension was created, and the infusion was made at 50 – 150g/ml concentrations. Anaerobic conditions were used to culture the pathogenic strain of microbial species, and DNA was extracted using an extraction kit. For testing, equalized standard dilutions of cultivated bacteria were utilized. The anti-bacterial capabilities of zinc oxide (ZnO) nanoparticles against bacteria were measured using spectroscopic and diffusion experiments. ZnO nanoparticles with a diameter of 50 nm and a concentration of 150 g/ml lysed Escherichia coli DNA and cells. According to the findings, ZnO nanoparticles with a concentration of 150 g/ml had significantly more vigorous activity against Escherichia coli. The agar diffusion method was used to quantify the anti-bacterial activity of zinc oxide (ZnO) and the quality and amount of DNA extraction in the presence of ZnO nanoparticles (ZnO). The pathogenic Escherichia coli cells and the gene DNA are killed at the optimal dose. This study aims to know the anti-bacterial properties of ZnO nanoparticles against pathogenic Escherichia coli cells. The optimization of ZnO nanoparticles concentration against its effect on Escherichia coli cells is the next aim of this study.

Comparative Study of Antibacterial Activity of Different ZnO Nanoparticles, Nanoflowers, and Nanoflakes

Aim: In this study, the antibacterial activity of zinc oxide (ZnO) nanostructures of different shapes, including nanoparticles, nanoflowers, and nanoflakes, was evaluated. Methods: The optical and morphological properties of the synthesized nanostructures were characterized by double-beam ultraviolet-visible (UV-Vis) analysis, X-ray diffraction (XRD) analysis, Energy Dispersive X-ray Analysis (EDX), and Scanning Electron Microscopy (SEM). Microdilution method was conducted, and minimum inhibitory concentration (MIC) was calculated to compare the antibacterial activity of the morphologically different nanostructures. Results: The SEM showed that ZnO-NPs were spherical in shape with a size of 100 nm. The EDX spectrum also showed that the synthesized ZnO-NPs were mainly composed of zinc, with the minimum contaminants being carbon and oxygen. The XRD analysis confirmed that the nature of the synthesized materials was ZnO with an average grain size of 3 nm to 21 nm. The greatest antibacterial activity of ZnO nanoparticles was against Pseudomonas aeruginosa, and for ZnO nanoflakes, against Escherichia coli. Conclusion: The study demonstrated that the antibacterial activity of nano-ZnO is shape-dependent.

Enhanced photocatalytic and antibacterial activity of ZnO with rice field crab chitosan and plectranthus amboinicus extract

Recently, there has been considerable interest in the development of hybrid nanomaterials for health and photocatalytic applications. This study describes the ecofriendly strategy for synthesis of zinc oxide (ZnO) nanoparticles immobilized chitosan (CS) obtained by deacetylation of rice field crab Paratelphusa hydrodromous shells in presence of Plectranthus amboinicus leaf extract (PLE). The resulting CS-ZnO-PLE hybrid nanocomposites were characterized by FT-IR, XRD, UV–Vis-DRS, HR-SEM, TEM, TGA and BET analysis. The HR-SEM study reveals that the CS-ZnO shows hexagonal structure after intercalation of PLE, their structure changed to hierarchical flower-like structure. Presence of reactive functional groups in the chitosan and phytochemicals such as thymol, carvacrol, p-cymene, β-caryophyllene, α-pinene, β-pinene, 1,8-cineole etc in the leaf extract plays a major role in the stabilization of the CS-ZnO-PLE hybrid nanocomposite. Spectroscopic findings reveal that photon energy from sunlight induces an electron that can be transferred from photoexcited chitosan to the conduction band of ZnO NP, which induces the production of reactive oxygen species (ROS) such as H2O2, ●OH and ●O2− are responsible for effective antibacterial and photocatalytic activities. The CS-ZnO-PLE hybrid nanocomposite shows enhanced photocatalytic degradation on methylene blue (∼98.97%) and drimarene red (∼87.43%) than CS-ZnO 67.53% and 30.46% respectively in the duration of 1 h exposure. The antibacterial activity was investigated in terms of inhibition zones using S.aureus and E.Coli bacterial strains and their inhibition zones were found to be 21 and 20 nm. These results provide valuable information for development of alternative chitosan material from rice field crab shells for high efficient photocatalytic and antibacterial activity with metal oxides.

Enhanced antibacterial activity of V-doped ZnO@SiO2 composites

Zinc oxide (ZnO) is an antibacterial agent with great potential in biological applications. However, the antibacterial activity of ZnO is relatively weak. In this study, a method of doping ZnO crystals with metals was employed to improve its antibacterial activity. V2O5-ZnO@SiO2 (V-ZS) composites, made of mesoporous SiO2 as a carrier, ZnO as an antibacterial agent, and V as a doping element, were fabricated by hydrothermal method at atmospheric pressure. The morphology, crystal structure, and chemical composition of V-ZS composites were analyzed by SEM, TEM, XRD, N2 physisorption, and XPS and the results were compared with those of undoped ZnO@SiO2 composites. UV–vis and PL spectroscopies were used to investigate the enhancement effect of V2O5 on the visible light absorption and separation of photogenerated carriers. The doping of ZnO with V was found to be favorable for the release of Zn2+ from ZnO particles and promoted the generation of reactive oxygen species. The enhancement effect of V2O5 depended on the percent of V2O5 in V2O5/ZnO nanostructures. The results of antibacterial activity revealed that even at a small amount of V2O5 (8%), action of the resulting 8%V-ZS composite increased against bacteria. It was also shown that V-ZS composites can mechanically damage the bacteria. The results obtained herein sustain the use of the developed composites in antibacterial products.

Controlled morphological and physical properties of ZnO nanostructures synthesized by domestic microwave route

The limited applications of ZnO in the visible light are still a challenge. In a short-term reaction (15 min), controlling the growth and morphology of zinc oxide in nano-structures had been achieved using a domestic microwave as a simple, quick and inexpensive tool. Besides, no seeds substrates were needed to be immersed during preparation process. Adding capping or complexing agents helped in controlling the surface morphology of ZnO, like hexamethylenetetramine, poly(vinyl pyrrolidone) (Polyvinyl alcohol), Hydrazine hydrate, trisodium citrate and ethylenediamine. The XRD results indicated the crystalline hexagonal wurtzite phase for all ZnO samples showing crystallite size ranged from 16.8 to 31.2 nm. SEM photos for the prepared ZnO NS samples demonstrated morphologies of twin-short rod, hexagonal rod, nanowires, nanosheet, and nanoflower structures. UV–visible and PL spectroscopy for measuring the optical properties showed that the band gap of ZnO samples ranged between 3.25 and 3.21 eV and still smaller than the standard value. Sample (M2) showed the highest intensity peak at 438 nm and high broad green emission peak at 511 nm. In brief, both solvent nature and crystal growth in the specific solvents are the keys to enforcing the crystal morphology. Eventually, the antibacterial activity of zinc oxide was evaluated in the presence and absence of UV radiation. Findings showed that all aqueous solution of ZnO samples irradiated by UV exhibit more antibacterial activity due to the increased amount of H2O2 generated which is fatal to bacteria.

Increasing the Shelf Life of Milk by Metal Oxide Nanoparticles and Mild Heat

Background: The spread of pathogenic microorganisms in food and beverage and their resistance to antibiotics have raised major concerns for public health. The aim of this study was to investigate the antimicrobial activity of various metal oxide nanoparticles (NPs) including zinc oxide (ZnO), magnesium oxide (MgO), and iron oxide (Fe2O3) NPs against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). Furthermore, the antimicrobial activity of these NPs in milk was studied along with mild heat.
 Methods: In this experimental study, the antibacterial activity of ZnO, MgO, and Fe2O3 NPs were initially evaluated by minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) methods. Later, the antimicrobial effect of these NPs was investigated in milk along with mild heating. To determine the morphological changes in S. aureus and E. coli, electron microscopy scanning was applied before and after the antimicrobial treatments.
 Results: The MBC and MIC values presented by Fe2O3, ZnO, and MgO NPs against pathogenic bacteria showed that MgO NPs were the most potent substances for inhibiting the growth of S. aureus and E. coli. The results also indicated that use of these NPs had synergistic effects in combination with the heating treatment. Electron microscopy scanning also revealed that treatment with MgO NPs could distort and impair the cell wall of the pathogenic bacteria, leading to the leakage of intracellular components and bacterial death.
 Conclusion: The results suggest that MgO, ZnO, and Fe2O3 NPs can be applied for industrial food processing as effective antimicrobial compounds to decrease the temperature required for pasteurizing milk.

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.

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.

CHARACTERIZATION AND ANTIBACTERIAL ACTIVITY OF ZnO NANOPARTICLES SYNTHESIZED BY CO PRECIPITATION METHOD

Objective: In the present study the antibacterial activity of zinc oxide (ZnO) nanoparticles was investigated against gram negative (Escherichia coli and Proteus vulgaris) and gram positive (Staphylococcus aureus and Streptococcus mutans) organisms.Methods: The synthesis of ZnO nanoparticles was carried out by co-precipitation method using zinc sulfate and sodium hydroxide as precursors. These nanoparticles were characterized by XRD (X-Ray Diffraction), FTIR (Fourier Transform Infrared Radiation), UV-Visible spectroscopy and SEM (Scanning Electron Microscope) with EDX (Energy Dispersive X-ray analysis). As well as antibacterial activity and minimum inhibitory concentration of the nanoparticles were carried out by agar well diffusion method and broth dilution method respectively against gram negative (Escherichia coli and Proteus vulgaris) and gram positive (Staphylococcus aureus and Streptococcus mutans) bacteria.Results: The average crystallite size of ZnO nanoparticles was found to be 35 nm by X-ray diffraction. The vibration bands at 450 and 603 cm-1 which were assigned for ZnO stretching vibration were observed in FTIR spectrum. The optical absorption band at 383 nm was obtained from UV-Visible spectrum. Spherical shape morphology was observed in SEM studies. The antibacterial assay clearly expressed that E. coli showed a maximum zone of inhibition (32±0.20 mm) followed by Proteus vulgaris (30±0.45 nm) at 50 mg/ml concentration of ZnO nanoparticles.Conclusion: Zinc oxide nanoparticles have exhibited good antibacterial activity with gram negative bacteria when compared to gram positive bacteria.

Antibacterial activity of zinc oxide and copper oxide nanoparticles against Gram-positive and Gram-negative bacterial strains ss

Antibacterial activity of zinc oxide and copper oxide nanoparticles against Gram-positive and Gram-negative bacterial strains ss

Physicochemical, osteogenic and corrosion properties of bio-functionalized ZnO thin films: Potential material for biomedical applications

Nano-sized zinc oxide (ZnO) is well known for its antibacterial activity and biocompatibility, which make this material a promising candidate to tailor titanium (Ti) implant surfaces. In an optimized scenario, the antibacterial activity of ZnO and its biocompatibility can be envisioned as a good bio-functionalization strategy to increase osteointegration. Thus, in this work, it is proposed that the bio-functionalization of ZnO thin films with dentin matrix protein 1 (DMP1) peptides could function as an apatite crystal nucleator. Ti was coated with ZnO and functionalized with two different spacers, 3-(4-aminophenyl) propionic acid (APPA) or 3-mercaptopropionic acid (MPA) to facilitate binding with DMP1 peptides. Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy and X-ray photoelectron spectroscopy (XPS) results confirmed the presence of the peptides on the ZnO thin film surface through characteristic bands related to amine and carboxylic acid groups and by the incidence of N 1 s spectra, respectively. Atomic force microscopy (AFM) images indicated that a more uniform layer of DMP1 peptides is formed in the the presence of the APPA and MPA spacers. In general, the results obtained showed that the bio-functionalized ZnO thin films with APPA spacer, ZnO APPA P sample, presented enhanced wettability (17°), surface energy (72 dyn/cm), with an osteogenic surface and apatite nucleating properties. Furthermore, the electrochemical analysis showed increased corrosion resistance with noble EOCP (−0.13 V), Ecorr (−0.46 V), and Icorr (8.91 ×10−7 A/cm2) values. These findings indicated promising applications of ZnO APPA P in biomedical devices once it can accelerate the osteointegration process and improve the corrosion resistance of implants.

Shape-controlled synthesis of three-dimensional zinc oxide nanoflowers for disinfection of food pathogens

The antibacterial activity of zinc oxide (ZnO) nanoflowers has been investigated and presented in this article. Classic three-dimensional nanoflowers have been prepared by hydrothermal method using zinc acetate dihydrate Zn(CH3COO)2·2H2O as the sole precursor. The X-ray diffraction and Fourier transform infrared spectra confirm the formation of ZnO crystals. Consequently, on the basis of morphological and chemical observations, the chemical reaction mechanism of ZnO nanoflowers was also proposed. Antibacterial activity was carried out against food-borne pathogen, Escherichia coli, which is ubiquitous in distribution among food-laden wastes. The experimental procedures for the antibacterial test included a spectroscopic method with different concentrations (5-20 μg/mL) of ZnO nanoflowers to unearth the minimum inhibitory concentration. Our investigation suggests that the lowest concentration of ZnO nanoflower solution that can hamper the growth of this microbial strain was 5 μg/mL.

Antibacterial activity of zinc oxide with silver nanoparticles

Nanoscale materials and their unique properties make them attractive for research and health -related applications. Silver nanoparticles were synthesised and incorporated in zinc oxide (ZnO) thin films on glass and tissue, in order to study their effect on antibacterial activity. ZnO films with various contents of Ag nanoparticles were prepared by the sol –gel method. Xray diffraction revealed the polycrystalline structure of the films, scanning electron microscopy exhibited their dense and continuous structure and UV-visible spectroscopy for measurement and transmittance was at more than 87%. The absorbance peak of Ag NPS was centred at 351 nm. The diameter of Ag NPS was analysed by Zeta Sizer and the colloids ranged from 2 to 110 nm. The results indicate that ZnO with Ag NPs on tissue can resist the growth of this kind of bacteria, with the zone of inhibition of the bacteria ATTC 700603 at between 8 and 18 mm .Keywords: Ag nanoparticles, zinc oxide, tissue, antibacterial activity.

Green synthesis of ZnO nanoparticles using the aqueous extract of Euphorbia petiolata and study of its stability and antibacterial properties

Through this study for the first time the biosynthesis, identification, stability and antibacterial activity of zinc oxide (ZnO) nanoparticles (NPs) was studied using the Euphorbia petiolata Banks aqueous extract as a reducing and stabilizing media during a simple and green method. Interaction of plant extract with the aqueous mixture of zinc nitrate and the oxidation via annealing process efficiently caused the reduction of the Zn ions and formation of zinc oxide nanoparticles. The stability, purity and crystalline nature of green synthesized nanoparticles was demonstrated using Uv-vis spectroscopy, EDS and XRD techniques, respectively. Also, the scheme of possible mechanism leading to the formation of NPs was illustrated. Moreover, the efficient antibacterial ability of green synthesized nanoparticles against Escherichia coli was demonstrated compared to the plant extract and chloramphenicol as positive control.

Antibacterial mechanism of ZnO nanoparticles under dark conditions

Abstract To evaluate the antibacterial activity of zinc oxide (ZnO) in the absence of a light source, we examined three different types of nanoparticles that vary in size and the number of oxygen defect sites. Colony forming units (CFU) and various microscopic investigations revealed that the antibacterial activity of ZnO nanoparticles under dark conditions was not related to reactive oxygen species (ROS) generation and nanoparticles transfection, but depended on the ZnO attachment to bacterial cell walls and increasing concentrations of Zn 2+ ions in the bacterial cytoplasm due to local dissolution of the attached ZnO.

ZnO nanoparticles obtained by pulsed laser ablation and their composite with cotton fabric: Preparation and study of antibacterial activity

A simple deposition method was used to prepare a ZnO/cotton fabric composite from water and ethanol dispersions of ZnO nanoparticles obtained by the pulsed laser ablation method. The structure and composition of the nanoparticles from dispersions and as-prepared composites were studied using electron microscopy, X-ray diffraction, and spectroscopy. The nanoparticles and composite obtained exhibited antibacterial activity to three different pathogenic microorganisms—Escherichia coli, Staphylococcus aureus, and Bacillus subtilis. An attempt to understand a mechanism of bactericidal effect of ZnO nanoparticles was made. It was shown that zinc ions and hydrogen peroxide were not responsible for antibacterial activity of the particles and the composite, and surface properties of nanoparticles played an important role in antibacterial activity of zinc oxide. The proposed composite is a promising material for use as an antibacterial bandage.

Nano-ZnO/ZnO–HAPw prepared via sol–gel method and antibacterial activities of inorganic agents on six bacteria associated with oral infections

The antibacterial activity of zinc oxide (ZnO) and the strengthening of hydroxylapatite whiskers (HAPws) have been widely studied and applied. However, the antibacterial properties of ZnO–HAPws have scarcely been researched. The aim of this study was to further investigate several types of nano-ZnO morphologies of ZnO–HAPws that were prepared using the sol–gel method at different pondus hydrogenii (pH) values and temperatures. The four morphologies of ZnO–HAPws that were investigated here were granule, triangle, short rod and disc type, and these morphologies were investigated at 70 °C at pH 6.4, 37 °C at pH 6.6, 70 °C at pH 6.6 and 70 °C at pH 6.6, respectively. Next, the antibacterial activity of ZnO–HAPw was compared to that of nano-ZnO, commercially available ZnO and tetrapod-like ZnO whiskers (T-ZnOw) with six bacteria that are associated with oral infections: Streptococcus mutans, Lactobacillus casei, Candida albicans, Actinomyces viscosus, Staphylococcus aureus and Escherichia coli. The results of examinations of the minimal inhibitory concentrations (MICs) and minimal bactericidal concentrations (MBCs) showed that the antibacterial activity of ZnO–HAPw exceeded that of the commercially available ZnO and T-ZnOw. Additionally, analysis of variance (ANOVA) analysis of the MBCs revealed that the four tested antibacterial agents had significantly different effects on S. mutans (F = 8.940; P = 0.006), S. aureus (F = 6.924; P = 0.013) and E. coli (F = 4.468; P = 0.04). ANOVA analyses of the MICs revealed that the four tested antibacterial agents had significantly different effects on S. mutans (F = 6.183; P = 0.018), A. viscosus (F = 4.531; P = 0.039) and S. aureus (F = 18.976; P = 0.001).

The Effect of Modification of Hydroxyapatite Whisker with Zinc Acetate via Sol-Gel Technology

Antibacterial activity of zinc oxide (ZnO) or strengthening of hydroxylapatite whisker (HAPw) had been studied and applied widely. However, antibacterial property of ZnO-HAPw was scarcely researched nowadays. The aim of this study was to further investigate several kinds of morphologies of ZnO-HAPw prepared by sol-gel technology at different pondus hydrogenii (pH) value and temperature. Four kinds of morphologies of ZnO-HAPw were granule, triangle, short rod and gongs nail at 70°C and pH=6.4, 37°C and pH=6.6, 70°C and pH=6.6, 70°C and pH=6.6. The SEM images of HAPw and ZnO-HAPw samples showed that the HAPw surface was smooth and no difference after annealing treatment. In addition, different shapes of nanoZnO fused uniformly on the HAPw surface. The EDS indicates nanoZnO fuses on HAPw surface.

Antibacterial activity of zinc oxide nanoparticle suspensions on food‐borne pathogens

Nanoparticles (NPs) are increasingly recognised for their utility in biological applications including nanomedicine and food safety. The present study investigated the antibacterial activity of zinc oxide (ZnO) when tested against the Gram‐negative bacteria Escherichia coli as well as the Gram‐positive bacterium Staphylococcus aureus, and the effect was more pronounced with the Gram‐positive than with the Gram‐negative bacteria. ZnO NPs also exhibited a preferential ability to suppress growth of E. coli and S. aureus in milk. This study suggested that the application of ZnO NPs as antibacterial agents in food systems and medicine may be effective at inhibiting certain pathogens.