Synthesis and Characterization Silver, Zinc Oxide and Hybrid Silver/Zinc Oxide Nanoparticles for Antimicrobial Applications

Nano LIFE ◽  
2014 ◽  
Vol 04 (01) ◽  
pp. 1440003 ◽  
Author(s):  
Myisha Roberson ◽  
Vijaya Rangari ◽  
Shaik Jeelani ◽  
Temesgen Samuel ◽  
Clayton Yates

Silver ( Ag ) and zinc oxide ( ZnO ) are well known for both antimicrobial and pro-healing properties. Here, we present a novel method to synthesize Ag and ZnO nanoparticles (NPs), as well as hybrid Ag / ZnO NPs using a custom, temperature controlled microwave assisted technique. Microwave synthesis has been shown not only to enhance the rate of chemical reactions, but also in some cases to give higher product yields over thermal heating. The as-synthesized NPs were characterized by X-ray diffraction (XRD) to study the crystalline structure, composition and purity. Transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS) was used to study particle size, shape, composition and morphology. These results indicated that the as-prepared Ag NPs are spherical in shape and ~ 20 nm in sizes. The ZnO NPs are typically rod shaped and the particle sizes are ~ 20 nm in width and 100 nm in length. These NPs were tested for antibacterial and/or antifungal properties using disc diffusion assays. Results show microwave synthesized NPs inhibit growth of S. aureus, E. coli and C. albicans at 50 μ g/mL treatment concentration. Ag NPs were most effective in inhibiting bacterial and fungal growth at the concentrations tested followed by hybrid Ag / ZnO and ZnO nanoparticles. These results also suggest that the hybridization of ZnO to Ag NPs may reduce the toxicity of Ag NPs. Further studies are needed to understand the functional interaction between the two types of NPs and to improve their ability for biological or biomedical application.

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2489
Author(s):  
Ami Yoo ◽  
Mengshi Lin ◽  
Azlin Mustapha

The application of nanoparticles (NPs) for food safety is increasingly being explored. Zinc oxide (ZnO) and silver (Ag) NPs are inorganic chemicals with antimicrobial and bioactive characteristics and have been widely used in the food industry. However, not much is known about the behavior of these NPs upon ingestion and whether they inhibit natural gut microflora. The objective of this study was to investigate the effects of ZnO and Ag NPs on the intestinal bacteria, namely Escherichia coli, Lactobacillus acidophilus, and Bifidobacterium animalis. Cells were inoculated into tryptic soy broth or Lactobacilli MRS broth containing 1% of NP-free solution, 0, 12, 16, 20 mM of ZnO NPs or 0, 1.8, 2.7, 4.6 mM Ag NPs, and incubated at 37 °C for 24 h. The presence and characterization of the NPs on bacterial cells were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDS). Membrane leakage and cell viability were assessed using a UV-visible spectrophotometer and confocal electron microscope, respectively. Numbers of treated cells were within 1 log CFU/mL less than those of the controls for up to 12 h of incubation. Cellular morphological changes were observed, but many cells remained in normal shapes. Only a small amount of internal cellular contents was leaked due to the NP treatments, and more live than dead cells were observed after exposure to the NPs. Based on these results, we conclude that ZnO and Ag NPs have mild inhibitory effects on intestinal bacteria.


2015 ◽  
Vol 29 (01) ◽  
pp. 1450254 ◽  
Author(s):  
M. Shayani Rad ◽  
A. Kompany ◽  
A. Khorsand Zak ◽  
M. E. Abrishami

Pure and silver added zinc oxide nanoparticles ( ZnO -NPs and ZnO : Ag -NPs) were synthesized through a modified sol–gel method. The prepared samples were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM) and photoluminescence (PL) spectroscopy. In the XRD patterns, silver diffracted peaks were also observed for the samples synthesized at different calcination temperatures of 500°C, 700°C, 900°C except 1100°C, in addition to ZnO . TEM images indicated that the average size of ZnO : Ag -NPs increases with the amount of Ag concentration. The PL spectra of the samples revealed that the increase of Ag concentration results in the increase of the visible emission intensity, whereas by increasing the calcination temperature the intensity of visible emission of the samples decreases.


Catalysts ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 608 ◽  
Author(s):  
Md. Hanif ◽  
Insup Lee ◽  
Jeasmin Akter ◽  
Md. Islam ◽  
Ali Zahid ◽  
...  

ZnO nanoparticles (ZnO-NPs) were synthesized by a straightforward modified thermal method using only one chemical: zinc acetate dihydrate. The process is environmentally safer than other methods because it does not involve other chemicals or a catalyst, acid, or base source. X-ray diffraction analysis indicated that the ZnO-NPs crystallize in the hexagonal wurtzite structure. The UV–vis absorption spectra revealed a marked redshift, which is critical for enhanced photocatalytic activity. We used methylene blue for photocatalytic activity tests and found an excellent degradation percentage (99.7%) within a short time (80 min). The antibacterial activity of the synthesized ZnO-NPs was tested against Escherichia coli at different concentrations of ZnO-NPs. The analysis revealed that the minimum inhibitory concentration (MIC) of the ZnO-NPs against E. coli was 30–50 μg/mL. Our ZnO-NPs were found to be more effective than previously reported ZnO-NPs synthesized via other methods.


Foods ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 442 ◽  
Author(s):  
Fabio Fontecha-Umaña ◽  
Abel Guillermo Ríos-Castillo ◽  
Carolina Ripolles-Avila ◽  
José Juan Rodríguez-Jerez

Food contact surfaces are primary sources of bacterial contamination in food industry processes. With the objective of preventing bacterial adhesion and biofilm formation on surfaces, this study evaluated the antimicrobial activity of silver (Ag-NPs) and zinc oxide (ZnO-NPs) nanoparticle-containing polyester surfaces (concentration range from 400 ppm to 850 ppm) using two kinds of bacteria, Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli), and the prevention of bacterial biofilm formation using the pathogen Listeria monocytogenes. The results of antimicrobial efficacy (reductions ≥ 2 log CFU/cm2) showed that at a concentration of 850 ppm, ZnO-NPs were effective against only E. coli (2.07 log CFU/cm2). However, a concentration of 400 ppm of Ag-NPs was effective against E. coli (4.90 log CFU/cm2) and S. aureus (3.84 log CFU/cm2). Furthermore, a combined concentration of 850 ppm Ag-NPs and 400 ppm ZnO-NPs showed high antimicrobial efficacy against E. coli (5.80 log CFU/cm2) and S. aureus (4.11 log CFU/cm2). The results also showed a high correlation between concentration levels and the bacterial activity of Ag–ZnO-NPs (R2 = 0.97 for S. aureus, and R2 = 0.99 for E. coli). They also showed that unlike individual action, the joint action of Ag-NPs and ZnO-NPs has high antimicrobial efficacy for both types of microorganisms. Moreover, Ag-NPs prevent the biofilm formation of L. monocytogenes in humid conditions of growth at concentrations of 500 ppm. Additional studies under different conditions are needed to test the durability of nanoparticle containing polyester surfaces with antimicrobial properties to optimize their use.


2014 ◽  
Vol 11 (2) ◽  
pp. 146-152 ◽  
Author(s):  
N Verma

Films of polyaniline and polyaniline–ZnO composites were synthesized by spin coating. The spin coated films were deposited over glass substrate. In order to confirm the dispersion quality and the size of the dispersed ZnO, Transmission electron microscopy was done. The TEM images show that ZnO nanoparticles were spherical in shape. Dark imaging mode confirmed these particles in solid phase and revealed the uniform distribution of the particles in the PANI matrix. The absorption peaks in FTIR spectra of PANI–ZnO composite film were found to shift to higher wave number when compared with pure PANI. The observed shifts were attributed to the interaction between the ZnO particle and PANI molecular chains. A change in the value of lattice parameter of ZnO as confirmed through the X ray diffraction method in the composite indicated the presence of interaction between ZnO particles and matrix. The dielectric study of PANI and PANI–ZnO composites demonstrated a significant decrease in the value of dielectric constant after the incorporation of the ZnO nanoparticles in the polymer matrix.


2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
K. Elen ◽  
A. Kelchtermans ◽  
H. Van den Rul ◽  
R. Peeters ◽  
J. Mullens ◽  
...  

Due to a dominant one-dimensional growth rate, nanoparticles of zinc oxide often show a rodlike morphology. As a result, the synthesis of small spherical nanoparticles of undoped ZnO remains challenging. This paper presents two procedures that successfully produce a powder consisting of equiaxed zinc oxide nanoparticles: one using a polyethylene glycol- (PEG-) assisted solvothermal method and the other by calcination of zinc oxalate obtained from a microemulsion-mediated method. In the latter, zinc-substituted aerosol OT (AOT) is used as a surfactant. The samples are characterized by inductively coupled plasma-atomic emission spectroscopy (ICP-AES), thermogravimetric analysis (TGA), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), photon correlation spectroscopy (PCS), and photoluminescence (PL) spectroscopy. Both synthesis techniques produce nanoparticles with similar sizes in the range of 10 to 20 nm. Dense aggregates observed in the calcined powder are infrequent in the case of the solvothermal method.


Dose-Response ◽  
2020 ◽  
Vol 18 (3) ◽  
pp. 155932582095891
Author(s):  
Sumera Sabir ◽  
Muhammad Asif Zahoor ◽  
Muhammad Waseem ◽  
Muhammad Hussnain Siddique ◽  
Muhammad Shafique ◽  
...  

Nano-fertilizer(s), an emerging field of agriculture, is alternate option for enhancement of plant growth replacing the synthetic fertilizers. Zinc oxide nanoparticles (ZnO NPs) can be used as the zinc source for plants. The present investigation was carried out to assess the role of ZnO NPs in growth promotion of maize plants. Biosynthesized ZnO NPs (using Bacillus sp) were characterized using Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), X-ray diffraction (XRD) and Zeta potential. Different concentrations of ZnO NPs (2, 4, 8, 16 mg/L) were explored in pot culture experiment. Size of ZnO NPs ranged between 16 and 20 nm. A significant increase in growth parameters like shoot length (61.7%), root length (56.9%) and significantly higher level of protein was observed in the treated plants. The overall pattern for growth biomarkers including the protein contents was maximum at 8 mg/L of ZnO NPs. It was observed that application of biosynthesized ZnO NPs has improved majority of growth biomarkers including plant growth parameters, protein contents and leaf area. Therefore, biosynthesized ZnO NPs could be considered as an alternate source of nutrient in Zn deficient soils for promoting the modern agriculture.


2011 ◽  
Vol 399-401 ◽  
pp. 407-414
Author(s):  
Guo Qiang Xu ◽  
Li Guo Sun ◽  
Shu Hong Wang ◽  
Yang Xie ◽  
Cheng Wang ◽  
...  

Zinc Oxide (ZnO) nanoparticles were firstly synthesized by the hydration of alkoxide. The as-synthesized ZnO were dispersed in the polyvinylpyrrolidone (PVP) solution. PVP/ZnO composite nanofibers were prepared via electrospinning the PVP/ZnO mixed solution. The morphology of ZnO nanoparticles and as-spun nanofibers was measured by scanning electron microscopy (SEM). The as-synthesized ZnO nanoparticles were homogeneous and stable, and their size ranged from 30 to 40 nm. The composite nanofibers showed a uniform and continuous morphology. With the increase of the ZnO content in the composite nanofibers, the diameter distribution of the composite nanofibers became wider. Transmission electron microscopy (TEM) images clearly showed that ZnO nanoparticles were distributed uniformly in the PVP/ZnO composite nanofibers without any aggregation, although the ZnO content reached as highly as 6 wt. %. The structures and properties of the composite nanofibers were investigated using X-ray diffraction (XRD), thermal gravimetric analysis (TGA), and Combined Stead State Fluorescence and Phosphorescence Lifetime Spectrometer (FLSP).


2016 ◽  
Vol 34 (4) ◽  
pp. 708-714 ◽  
Author(s):  
Yan Li ◽  
Fang-Xian Zhao ◽  
Xiao-Xue Lian

AbstractAu-modified ZnO (Au/ZnO) nanoparticles (NPs) synthesized using bamboo cellulose template and calcination process were characterized using X-ray diffraction, field-emission scanning electron microscopy, and transmission electron microscopy. The gas-sensing performance of Au/ZnO NPs based sensors was also examined. The results indicated that the Au/ZnO NPs exhibited enhanced gas-sensing performance compared with that of pure ZnO. The response of the Au/ZnO NPs to 100 ppm ethanol (50) at 240 °C was nearly 2.7 times higher than that to acetone (18.4) and approximately 12.5 times higher than that to benzene (4.1), carbon monoxide (1.6), hydrogen (1.6), and methane (1.8), respectively, which demonstrated their higher selectivity to ethanol versus other gases. This high response to ethanol could be attributed to the small size, Schottky barrier, and catalysis.


Biomolecules ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 336 ◽  
Author(s):  
Mohammad Azam Ansari ◽  
Mahadevamurthy Murali ◽  
Daruka Prasad ◽  
Mohammad A. Alzohairy ◽  
Ahmad Almatroudi ◽  
...  

Cinnamomum verum plant extract mediated propellant chemistry route was used for the green synthesis of zinc oxide nanoparticles. Prepared samples were confirmed for their nano regime using advanced characterization techniques such as powder X-ray diffraction and microscopic techniques such as scanning electron microscopy and transmission electron microscopy. The energy band gap of the green synthesized zinc oxide (ZnO)-nanoparticles (NPs) were found between 3.25–3.28 eV. Fourier transmission infrared spectroscopy shows the presence of Zn-O bond within the wave number of 500 cm−1. SEM images show the specific agglomeration of particles which was also confirmed by TEM studies. The green synthesized ZnO-NPs inhibited the growth of Escherichia coli and Staphylococcus aureus with a minimum inhibitory concentration (MIC) of 125 µg mL−1 and 62.5 µg mL−1, respectively. The results indicate the prepared ZnO-NPs can be used as a potential antimicrobial agent against harmful pathogens.


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