Antibacterial Activity Of ZnO Nanoparticles Research Articles

Study of ZnO nanoparticles: Antibacterial property and light depolarization property using light scattering tool

Investigations on treatment of ZnO nanoparticles on Staphylococcus aureus MTCC 737 strain was essentially made by using standard biochemical method. The anti-microbial assay against S. aureus, and time kill assay revealed the anti-bacterial activity of ZnO nanoparticles. We have substantiated this property of ZnO nanoparticles and light depolarization property by using light scattering tool. Light scattering measurements were carried out for ZnO, S. aureus, and ZnO treated S. aureus as a function of scattering angle at 543.5 and 632.8nm wavelengths. This was done in order to find the scattering profile of the consequent product after the action of ZnO nanoparticles on bacteria by means of light scattering tool. S. aureus treated with ZnO nanoparticles showed closer agreement of the scattering profiles at both the wavelengths, however, the scattering profiles of ZnO nanoparticles and untreated S. aureus significantly varied for the two different laser wavelengths. It was also observed that there was higher intensity of scattering from all S. aureus treated with ZnO particles compared to the untreated ones. In our work, we have studied ZnO nanoparticles and the possibility of observing its anti-bacterial activity by using light scattering tool.

Synthesis, Characterization and Antibacterial Activity of ZnO Nanoparticles of Different Morphology

Nanometric zinc oxide was prepared by sol-gel method using two different capping agents e.g., ethylene diamine (EDA) and citric acid (CAM) in different solvents. Nanorods of ZnO was prepared by sol-gel method using zinc nitrate hexahydrate (1M). The as-synthesized samples were characterized using XRD, FESEM-EDAX, TG/DTA techniques. FESEM micrographs suggest that the formation of nanorods of ZnO takes place for EDA and CAM in MeOH after calcination at 150 °C and 170 °C, respectively for 12h. The antibacterial activity tests (also known as plus-minus tests) were done by allowing bacteria to grow normally in laboratory conditions, and also by subjecting to ZnO nanoparticles in the powder form. On comparison of the above two Petri plates, the presence of a zone of inhibition indicates the antibacterial nature, which would have not existed if the bacteria did not experience any adverse effects by the presence of the ZnO nanorods. In the present study, the activity tested against Escherichia coli ATCC 25922 (gram-negative) Micrococcus leuteus and Bacillus subtilis (gram-positive) the results suggest the selective activity of the nanoparticles against these species.

Antibacterial activity of ZnO nanoparticles with a modified surface under ambient illumination

In various practical applications, nanomaterials typically have functionalized surfaces. Yet, the studies of toxicity and antibacterial activity of functionalized nanoparticles are scarce. We investigated the effect of surface modifications on antibacterial activity of ZnO under ambient illumination, and we found that nanoparticles coated with different surface modifying reagents could exhibit higher or lower toxicity compared to bare ZnO, depending on the surface modifying reagent used. Different surface modifying reagent molecules resulted in differences in the release of Zn2+ ions and the production of reactive oxygen species (ROS). However, the antibacterial activity did not correlate with the ROS levels or the Zn2+ ion release. One of the surface-modified ZnO samples exhibited significantly lower Zn2+ ion release while at the same time exhibiting improved antibacterial activity. In all cases, damage of the cell wall membranes and/or changes in the membrane permeability have been observed, together with the changes in ATR-FTIR spectra indicating differences in protein conformation. Mechanisms of antibacterial activity are discussed.

Influence of size scale and morphology on antibacterial properties of ZnO powders hydrothemally synthesized using different surface stabilizing agents

Metal oxide nanoparticles represent a new class of important materials that are increasingly being developed for use in research and health-related applications. Although the antibacterial activity and efficiency of bulk zinc oxide were investigated in vitro, the knowledge about the antibacterial activity of ZnO nanoparticles remains deficient. In this study, we have synthesized ZnO particles of different sizes and morphologies with the assistance of different types of surface stabilizing agents – polyvinyl pyrrolidone (PVP), polyvinyl alcohol (PVA) and poly (α,γ, l-glutamic acid) (PGA) – through a low-temperature hydrothermal procedure. The characterization of the prepared powders was preformed using X-ray diffraction (XRD) method and field emission scanning electron microscopy (FE SEM), as well as Malvern's Mastersizer instrument for particle size distribution. The specific surface area (SSA) of the ZnO powders was measured by standard Brunauer–Emmett–Teller (BET) technique.The antibacterial behavior of the synthesized ZnO particles was tested against gram-negative and gram-positive bacterial cultures, namely Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), respectively. We compared the results of the antibacterial properties of the synthesized ZnO samples with those of the commercial ZnO powder. According to the obtained results, the highest microbial cell reduction rate was recorded for the synthesized ZnO powder consisting of nanospherical particles. In all of the examined samples, ZnO particles demonstrated a significant bacteriostatic activity.

Antibacterial activity of ZnO nanoparticle on Gram-positive and Gram-negative bacteria

The aim of the present study is to determine the antimicrobial activity of ZnO nanoparticles against Gram-negative and Gram-positive bacteria. Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were used as test microorganisms. The effects of particle size and concentration on the antibacterial activity of ZnO nanoparticles was studied using bacteriological tests such as disc and well diffusion agar methods, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). 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 E. coli and S. aureus was measured with respect of time. The minimum inhibitory concentration was determined using seven different concentrations of ZnO nanoparticles including 16, 8, 4, 2, 1 and 0.5 mg/ml. The MIC value for E. coli and S. aureus was 1 and 0.5 mg/ml, respectively. The results showed that ZnO nanoparticles have antibacterial inhibition zone of 29 and 19 mm at the concentration of 10 mg/ml against E. coli and S. aureus, respectively. Gram-negative bacteria seemed to be more resistant to ZnO nanoparticles than Gram-positive bacteria. It was found that the antibacterial activity of ZnO nanoparticles increased with decreasing particle size and increasing powder concentration. The antibacterial effect of ZnO nanoparticles was time dependent and takes effect gradually. ZnO bulk powder showed no significant antibacterial activity. Key word: ZnO nanoparticle, Escherichia coli, Staphylococcus aureus, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC).

An assessment of antibacterial activity of ZnO nanoparticles, Catechin, and EDTA on standard strain of pseudomonas aeroginusa

Introduction: Pseudomonas aeruginosa is a key opportunistic pathogen causing severe acute and chronic nosocomial infections in immunocompromised or catheterized patients. It is prevalent in burn wound infections and is generally multi-drug resistant.This study evaluated antimicrobial activity of ZnO nanoparticles, catechin and EDTA on the most common pathogen bacteria, Pseudomonas aeroginusa, by standard microdilution test depending on NCCLS. Material and Methods: Zinc acetate dehydrate and ethilen glycol (EG) were dissolved in 50 ml distilled water with a ratio of 10/1 (Zn/EG). The solution was heated at 80 0 C until a little gel of zinc acetate was obtained. Then, the gel was dried in the oven for 12h. The dried gel was calcinated at 300 0 C for 24h. The size and type of these nanoparticles were characterized by scanning electron microscopy (SEM) and X-Ray-: Diffraction (XRD). Pseudomonas aeroginusa strain (ATCC 27853) were cultured on nutrient agar medium (NA) for 24h at 37 0 C. The microbial suspension (1×10 6 cells/ml) was prepared. Minimum Inhibitory Concentration (MIC) test for ZnO, EDTA and Catechin were evaluated by microdilution test. Results: Evaluation of morphology and measurement of the size of the ZnO showed that nanoparticles were spherical with a diameter of 30-90 nm. MIC of ZnO, EDTA and Catechin on pseudomonas aeroginusa was 0.0003, 24.92 and 7.24 μg/ml, respectively. Conclusion: In this study, ZnO nanoparticles were synthesized using the chemical method. It was revealed that it has an optimal antimicrobial activity in low concentration as compared with Catechin and EDTA. It is recommended that catechin and ZnO nanoparticles are good candidates for eliminating some contaminations including Pseudomonas aeroginusa in medical industrial.

Studies on antibacterial activity of ZnO nanoparticles by ROS induced lipid peroxidation

Recent studies indicated the role of ROS toward antibacterial activity. In our study we report ROS mediated membrane lipid oxidation of Escherichia coli treated with ZnO nanoparticles (NPs) as supported by detection and spectrophotometric measurement of malondialdehyde (MDA) by TBARS (thiobarbituric acid-reactive species) assay. The antibacterial effects of ZnO NPs were studied by measuring the growth curve of E. coli, which showed concentration dependent bacteriostatic and bacteriocidal effects of ZnO NPs. The antibacterial effects were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Further, antibacterial effect of ZnO NPs was found to decrease by introducing histidine to the culture medium treated with ZnO NPs. The ROS scavenging action of histidine was confirmed by treating histidine to the batch of Escherichia coli+ZnO NPs at the end of the lag phase of the growth curve (Set-I) and during inoculation (Set-II). A moderate bacteriostatic effect (lag in the E. coli growth) was observed in Set-II batch while Set-I showed no bacteriostatic effect. From these evidences we confirmed that the antibacterial effect of bare as well as TG capped ZnO NPs were due to membrane lipid peroxidation caused by the ROS generated during ZnO NPs interaction in culture medium.

Characterization of clinical strains of MSSA, MRSA and MRSE isolated from skin and soft tissue infections and the antibacterial activity of ZnO nanoparticles

Staphylococcus aureus, particularly methicillin-resistant S. aureus (MRSA), is an important cause of pyogenic skin and soft tissue infections (SSTIs). MRSA is an important pathogen in the healthcare sector that has neither been eliminated from the hospital nor community environment. In humans, S. aureus causes superficial lesions in the skin and localized abscesses, pyogenic meningitis/encephalitis, osteomyelitis, septic arthritis, invasive endocarditis, pneumonia, urinary tract infections and septicemia. Investigations focused in the search of other alternatives for the treatment of MRSA infections are in progress. Among the range of compounds whose bactericidal activity is being investigated, ZnO nanoparticles (ZnO-NPs) appears most promising new unconventional antibacterial agent that could be helpful to confront this and other drug-resistant bacteria. The aim of present study is to investigate the antibacterial potential of ZnO-NPs against Staphylococcus species isolated from the pus and wounds swab from the patients with skin and soft tissue infections in a tertiary care hospital of north India. ZnO-NPs (≈19.82 nm) synthesized by sol-gel process were characterized using scanning electron microscopy, X-ray diffraction , and Atomic force microscopy. The antibacterial potential was assessed using time-dependent growth inhibition assay, well diffusion test, MIC and MBC test and colony forming units methods. ZnO-NPs inhibited bacterial growth of methicillin-sensitive S. aureus (MSSA), MRSA and methicillin-resistant S. epidermidis (MRSE) strains and were effective bactericidal agents that were not affected by drug-resistant mechanisms of MRSA and MRSE.

Interaction of ZnO Nanoparticles with Microbes—A Physio and Biochemical Assay

The antibacterial activity of ZnO nanoparticles (nano ZnO) on various microorganisms has been investigated in this study and acting mechanism is proposed for E. coli a model organism by analyzing the growth, permeability and morphology of the bacterial cells. The experimental results indicated 1 mmoL (81.4 microg) nano ZnO could completely inhibit the growth of 10(7) cfu/mL bacterial cells in liquid Luria-Betrani medium. In the biochemical study, it has been observed that, nano ZnO resulted in the leakage of proteins. Chemiluminescence assay proved the generation of the reactive oxygen species into active state. When the cells of E. coli were exposed to nano ZnO, many pits were observed in bacterial cells by TEM and Fluorescence microscopy and the cells were found to be fragmentary. Released zinc ion from has been monitored by AAS. It suggested that nano ZnO is able to destroy the permeability of the bacterial membranes. Our study demonstrated that nano ZnO damages the structure of bacterial cell membrane and depressed the activity of some membranous enzymes by ROS production which caused E. coli bacteria to die eventually.

Light scattering study of zinc oxide nanoparticles for the application of its anti-bacterial property

Investigations on the anti-bacterial activity of ZnO nanoparticles on Staphylococcus aureus were made by using bio-technical method. Light scattering properties of these particles were studied as a function of scattering angle by using a versatile laboratory light scattering setup in order to find the scattering profile of ZnO nanoparticles and also the mode of action of these particles on bacterial property.

ANTIBACTERIAL ACTION OF ZINC OXIDE NANOPARTICLES AGAINST FOODBORNE PATHOGENS

ABSTRACTThe 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), compared with conventional ZnO powder, against nine bacterial strains, mostly foodborne including pathogens, was evaluated using qualitative and quantitative assays. ZnO NP was more efficient as antibacterial agent than powder. Gram‐positive bacteria were generally more sensitive to ZnO than Gram negatives. The exposure of Salmonella typhimurium and Staphylococcus aureus to their relevant minimal inhibitory concentrations from ZnO NP reduced the cell number to zero within 8 and 4 h, respectively. Scanning electron micrographs of the treated bacteria with NPs exhibited that the disruptive effect of ZnO on S. aureus was vigorous as all treated cells were completely exploded or lysed after only 4 h from exposure. Promising results of ZnO NP antibacterial activity suggest its usage in food systems as preservative agent after further required investigations and risk assessments.PRACTICAL APPLICATIONSFoodborne pathogen invasion is still a recurrent serious problem facing researchers and food industry overseers. The introduction of novel powerful antimicrobial agents is of great importance for the control of pathogenic bacteria, especially antibiotic‐resistant strains. Zinc oxide (ZnO) nanoparticle (NP) could be one of these potential alternatives. This study focused on ZnO NP because of its increasing presence in many marketable products and that supports its application in food industries as a reasonably safe agent. The demonstrated antibacterial activity of ZnO NP recommends its possible application in the food preservation field; otherwise it can be applied as a potent sanitizing agent for disinfecting and sterilizing food industry equipment and containers against the attack and contamination with foodborne pathogenic bacteria.

Size-Dependent Bacterial Growth Inhibition and Mechanism of Antibacterial Activity of Zinc Oxide Nanoparticles

The antibacterial properties of zinc oxide nanoparticles were investigated using both gram-positive and gram-negative microorganisms. These studies demonstrate that ZnO nanoparticles have a wide range of antibacterial activities toward various microorganisms that are commonly found in environmental settings. The antibacterial activity of the ZnO nanoparticles was inversely proportional to the size of the nanoparticles in S. aureus. Surprisingly, the antibacterial activity did not require specific UV activation using artificial lamps, rather activation was achieved under ambient lighting conditions. Northern analyses of various reactive oxygen species (ROS) specific genes and confocal microscopy suggest that the antibacterial activity of ZnO nanoparticles might involve both the production of reactive oxygen species and the accumulation of nanoparticles in the cytoplasm or on the outer membranes. Overall, the experimental results suggest that ZnO nanoparticles could be developed as antibacterial agents against a wide range of microorganisms to control and prevent the spreading and persistence of bacterial infections.

Antibacterial activity of ZnO nanoparticles prepared via non-hydrolytic solution route

The antibacterial activity of ZnO nanoparticles has been investigated and presented in this paper. Nanoparticles were prepared via non-hydrolytic solution process using zinc acetate di-hydrate (Zn(CH(3)COO)(2).2H(2)O) and aniline (C(6)H(5)NH(2)) in 6 h refluxing at approximately 65 degrees C. In the presence of four pathogens such as Staphylococcus aureus, Escherichia coli, Salmonella typhimurium, and Klebsiella pneumoniae, the antibacterial study of zinc oxide nanoparticles were observed. The antibacterial activity of ZnO nanoparticles (ZnO-NPs) were studied by spectroscopic method taking different concentrations (5-45 microg/ml) of ZnO-NPs. Our investigation reveals that the lowest concentration of ZnO-NPs solution inhibiting the growth of microbial strain is found to be 5 microg/ml for K. pneumoniae, whereas for E. coli, S. aureus, and S. typhimurium, it was calculated to be 15 microg/ml. The diameter of each ZnO-NPs lies between "20 and 30 nm" as observed from FESEM and transmission electron microscopy images. The composition of synthesized material was analyzed by the Fourier transform infrared spectroscopy, and it shows the band of ZnO at 441 cm(-1). Additionally, on the basis of morphological and chemical observations, the chemical reaction mechanism of ZnO-NPs was also proposed.

Enhanced bioactivity of ZnO nanoparticles—an antimicrobial study

In this study, we investigate the antibacterial activity of ZnO nanoparticles with various particle sizes. ZnO was prepared by the base hydrolysis of zinc acetate in a 2-propanol medium and also by a precipitation method using Zn(NO3)2 and NaOH. The products were characterized by x-ray diffraction (XRD) analysis, transmission electron microscopy (TEM) and photoluminescence (PL) spectroscopy. Bacteriological tests such as minimum inhibitory concentration (MIC) and disk diffusion were performed in Luria-Bertani and nutrient agar media on solid agar plates and in liquid broth systems using different concentrations of ZnO by a standard microbial method for the first time. Our bacteriological study showed the enhanced biocidal activity of ZnO nanoparticles compared with bulk ZnO in repeated experiments. This demonstrated that the bactericidal efficacy of ZnO nanoparticles increases with decreasing particle size. It is proposed that both the abrasiveness and the surface oxygen species of ZnO nanoparticles promote the biocidal properties of ZnO nanoparticles.