Activity Of ZnO Nanoparticles Research Articles

Evaluation of antimicrobial and antioxidant activity of zinc oxide nanoparticles biosynthesized with Ziziphus spina-christi leaf extracts

Background: Due to their simplicity, eco-friendliness, availability and non-toxicity, the greener fabrication of metal and metal oxide nanoparticles has been a highly attractive research area over the last decade. Aim: This study aimed to assess the antioxidant and antimicrobial activities of the green synthesized zinc oxide nanoparticles (ZnO-NPs) using an aqueous leaf extract of Ziziphus spina-christi. Method: The antioxidant property of ZnO-NPs was analyzed by the α, α-diphenyl-β-picrylhydrazyl (DPPH) and hydrogen peroxide (H2O2). Additionally, the diffusion agar method assessed the antimicrobial activities against bacteria and fungi. Results: ZnO-NPs synthesized by Z. spina-christi had shown promising H2O2 and DPPH free radical scavenging actions compared to vitamin C. The ZnO-NPs exhibited significant antibacterial activity against the tested bacteria with various susceptibility as a concentration-dependent effect. The largest zone of inhibition for Staphylococcus aureus (S. aureus) was observed (36 ± 2 mm) compared to Escherichia coli (E. coli) (15 ± 2 mm) by the same concentration of ZnO-NPs. The ZnO-NPs showed remarkable antifungal activity against Aspergillus niger. Conclusion: It can be concluded that, ZnO-NP have been imposed as suitable antimicrobial agent being able to combat both S. aureus and E. coli in vitro.

Green Synthesis, Characterization, and Photocatalytic Activity of Zinc Oxide Nanoparticles on Photodegradation of Naphthol Blue Black Dye

Zinc oxide (ZnO) nanoparticles have been successfully synthesized using water extract of red dragon fruit (Hylocereus polyrhizus) stem with zinc acetate dihydrate as a precursor of ZnO. Chemical compounds contained in the red dragon fruit stem extract, such as phenolics, terpenoids, and steroids, acted as reducing agents, stabilizers, and capping agents. The phase structure, crystallite size, functional groups, shape, and morphology of ZnO nanoparticles were determined by X-ray diffraction (XRD), Fourier Transform infrared (FT-IR) Spectroscopy, and Scanning Electron Microscopy-Energy Dispersive X-ray (SEM-EDX). The XRD pattern confirmed the crystallinity of synthesized zinc oxide was in the zincite (ZnO) phase with an average crystallite size of 79.09 nm. Spectroscopy FTIR analysis showed that the synthesized ZnO nanoparticles had characteristics similar to the ZnO standard/commercial. SEM-EDX analysis revealed that the synthesized ZnO nanoparticles were spherical, evenly distributed, and homogeneous particle size. The photocatalytic activity of synthesized ZnO nanoparticles was evaluated on the photodegradation of naphthol blue black (NBB) dye. The results showed that the synthesized ZnO nanoparticles have high photocatalytic activity that can degrade NBB dye up to 98.82%. This high photocatalytic activity was obtained at operating parameter conditions with the initial pH of NBB at 2, the dosage of ZnO nanoparticles at 250 mg, and the initial dye concentration at 10 ppm.

Anticancer Activities of Zinc Oxide Nanoparticles Synthesized Using Guava Leaf extract.

AbstractIn this study, we report on the green synthesis, characterization, and anticancer activity of zinc oxide nanoparticles (ZnO NPs) prepared using extracts of guava leaves. The ZnO NPs were successfully synthesized using a simple and eco‐friendly method. Then, the synthesized NPs were characterized using various techniques including Fourier‐transform infrared spectroscopy, X‐ray diffraction, scanning electron microscopy, and transmission electron microscopy. The results confirmed the formation of ZnO NPs with an average size of approximately 20 nm, along with a spherical morphology and well‐defined boundaries. The anticancer activity of the synthesized NPs was evaluated against different cancer cell lines, including A549 (lung cancer), HeLa (cervical cancer), and MCF7 (breast cancer), as well as normal human dermal fibroblast (HDF) cells. The analysis showed that the ZnO NPs exhibited significant anticancer activity, especially against the MCF7 and HeLa cancer cell lines, along with relatively low toxicity toward HDF cells. These findings highlight the potential of ZnO NPs synthesized using guava leaf extract as promising candidates for biomedical applications, particularly in cancer therapy.

Facile synthesis of ZnO nanoparticles by thermal decomposition of Schiff base complexes for the effective removal of organic pollutants in an aqueous medium

A series of mononuclear Schiff base transition metal complexes of the type [M(LS)(temed)] (where, M = Co(II), Ni(II), Cu(II), and Zn(II); LS = Schiff base ligand derived from L-leucine and Salicylaldehyde and co-ligand temed = N,N,N’N’- tetramethylethylenediamine) have been synthesized and characterized by spectroscopic studies such as Mass, NMR, UV–Visible, FT-IR, and TGA analysis. Spectral results reveal that the metal ions are coordinated to imine nitrogen, phenolic oxygen, and oxygen atom present in the carboxylate group of the Schiff base ligand and two nitrogen atoms from ligand (L2) temed. The scavenging activity of the complexes was carried out by the DPPH method with different concentrations, and all the complexes possesses good antioxidant activity in the range 58.93 to 78.79 %. Among them Zn(II) complex showed higher scavenging activity 78.79 % using 10 mg concentration. Furthermore, an investigation was conducted to assess the antibacterial properties of the complexes. It was observed that all of the metal complexes exhibited significant antimicrobial activity. Notably, the copper complex demonstrated enhanced activity, particularly against S. aureus and Mucor species, with zone of inhibition measurements of 19 mm and 20 mm, respectively. The Zn(II) complex has been used as a precursor to produce zinc oxide nanoparticles by the thermal decomposition method. ZnO nanoparticles have been characterized by powder X-ray diffraction (PXRD), UV–Vis spectroscopy techniques, scanning electron microscopy (SEM), FT-IR spectroscopy. The photocatalytic activity of zinc oxide nanoparticles was investigated in the presence of ultraviolet light. ZnO nanoparticles can efficiently catalyze the degradation of methyl orange, methylene blue, and rhodamine B in the aqueous suspension, and the highest percentage of degradation was observed against methylene blue (99 %). Furthermore, the impact of altering dye concentration, pH, catalyst quantity and kinetics on the photodegradation of model pollutant methylene blue was investigated.

Synthesis and characterization of 4-nitro benzaldehyde with ZnO-based nanoparticles for biomedical applications.

Globally, cancer is the leading cause of death and morbidity, and skin cancer is the most common cancer diagnosis. Skin problems can be treated with nanoparticles (NPs), particularly with zinc oxide (ZnO) NPs, which have antioxidant, antibacterial, anti-inflammatory, and anticancer properties. An antibacterial activity of zinc oxide nanoparticles prepared in the presence of 4-nitrobenzaldehyde (4NB) was also tested in the present study. In addition, the influence of synthesized NPs on cell apoptosis, cell viability, mitochondrial membrane potential (MMP), endogenous reactive oxygen species (ROS) production, apoptosis, and cell adhesion was also examined. The synthesized 4-nitro benzaldehyde with ZnO (4NBZnO) NPs were confirmed via characterization techniques. 4NBZnO NPs showed superior antibacterial properties against the pathogens tested in antibacterial investigations. As a result of dose-based treatment with 4NBZnO NPs, cell viability, and MMP activity of melanoma cells (SK-MEL-3) cells were suppressed. A dose-dependent accumulation of ROS was observed in cells exposed to 4NBZnO NPs. As a result of exposure to 4NBZnO NPs in a dose-dependent manner, viable cells declined and apoptotic cells increased. This indicates that apoptotic cell death was higher. The cell adhesion test revealed that 4NBZnO NPs reduced cell adhesion and may promote apoptosis of cancer cells because of enhanced ROS levels.

Differential Impact of Zinc Salt Precursors on Physiognomies, Anticancerous, and Antibacterial Activities of Zinc Oxide Nanoparticles.

Zinc oxide nanoparticles (ZnONPs) are enormously popular semi-conductor metal oxides with diverse applications in every field of science. Many physical and chemical methods applied for the synthesis of ZnONPs are being rejected due to their environmental hazards. Therefore, ZnONPs synthesized from plant extracts are steered as eco-friendly showing more biocompatibility and biodegradability. Additionally, various synthesis conditions such as the type of precursor salt also play a role in influencing the physicochemical and biological properties of ZnONPs. In this study, green synthesis of ZnONPs from Acacia nilotica was carried out using zinc acetate (ZA-AN-ZNPs), zinc nitrate (ZN-AN-ZNPs), and zinc sulfate (ZS-AN-ZNPs) precursor salts. Surprisingly, characterization of ZnONPs using UV-visible spectroscopy, TEM, XRD, and EDX revealed the important role precursor salts played in influencing the size and shape of ZnONPs, i.e., 20-23nm spherical (ZA-AN-ZNPs), 55-59nm triangular (ZN-AN-ZNPs), and 94-97nm nano-flowers (ZS-AN-ZNPs). FTIR analysis showed the involvement of alkaloids, alcohols, carboxylic acid, and phenolic compounds present in Acacia nilotica extract during the synthesis process. Since different precursor salts showed different morphology of ZnONPs, their biological activities were also variable. ZN-AN-ZNPs showed the highest cytotoxicity towards HepG2 cells with the lowest cell viability (28.92 ± 0.99%), highest ROS/RNS production (3425.3 ± 184.58 relative DHR123 fluorescence), and loss of mitochondrial membrane potential (1645.2 ± 32.12 relative fluorescence unit) as well as induced significant caspase-3 gene expression. In addition to this, studying the zone of inhibitions and minimum bactericidal and inhibitory concentrations of ZnONPs showed their exceptional potential as antibacterial agents. At MIC as low as 8µg/mL, ZA-AN-ZNPs and ZN-AN-ZNPs exhibited significant bactericidal activities against human pathogens Klebsiella pneumoniae and Listeria monocytogenes, respectively. Furthermore, alkaline phosphatase, DNA/RNA leakage, and phosphate ion leakage studies revealed that a damage to the bacterial cell membrane and cell wall is involved in mediating the antibacterial effects of ZnONPs.

Evaluation of Anti-Diabetic Activity of Zinc Oxide Nanoparticles of Gymnema sylvestre Extract on Wistar Rats

Diabetes mellitus is described as a metabolic disorder, which was characterised by high blood glucose levels, which were resulted due to insufficient insulin secretion. There were major complications related to diabetes mellitus. To evaluate the antidiabetic effect of Gymnema sylvestre Zinc Oxide Nanoparticles. Streptozotocin (STZ) of 50mg/kg is used for the induction of diabetes into Wistar rats. The animals were divided into 6 groups. Group-I represented as Control; Group-II represented as diabetic control (STZ ); Group-III represented as 5 mg/kg body weight of glibenclamide + diabetes; Group-IV represented as Gymnema sylvestre extract + diabetes; Group-V represented as 100 µg Gymnema sylvestre Zinc Oxide nanoparticles + diabetes; group-6- Gymnema sylvestre Zinc Oxide Nanoparticles 200 µg + diabetes. The GsZnONPs were inspected to morphological properties using UV spectrophotometer and FTIR. The GsZnONPs shown characterization peak at 300nm. The study has shown that GsZnONPs treated group has shown reduced glucose concentration. The histo-pathological alterations were also studied in all experimental groups. The pathology results of GsZnONPs (200 µg) group has shown the regeneration of islets cells of pancreas. The research study has proved that Gymnema sylvestre ZnO NPs exerts antidiabetic properties.
 Keywords: Diabetes, Gymnema sylvestre, Zinc Oxide nanoparticles

Assessment of antimicrobial activity and In Vitro wound healing potential of ZnO nanoparticles synthesized with Capparis spinosa extract.

Agents that will accelerate wound healing maintain their clinical importance in all aspects. The aim of this study is to determine the antimicrobial activity of zinc oxide nanoparticles (ZnO NPs) ZnO nanoparticles obtained by green synthesis from Capparis spinosa L. extract and their effect on in vitro wound healing. ZnO NPs were synthesized and characterized using Capparis spinosa L. extract. ZnO NPs were tested against nine ATCC-coded pathogen strains to determine antimicrobial activity. The effects of different doses (0.0390625-20 µg/mL) of NPs on cell viability were determined by MTT assay. The effect of ZnO NPs doses (0.0390625 µg/mL, 0.078125 µg/mL, 0.15625 µg/mL, 0.3125 µg/mL, 0.625 µg/mL, 1.25 µg/mL) that increase proliferation and migration on wound healing was investigated in an in vitro wound experiment. Cell culture medium obtained from the in vitro wound assay was used for biochemical analysis, and plate alcohol-fixed cells were used for immunohistochemical staining. It was determined that NPs formed an inhibition zone against the tested Gram-positive bacteria. The ZnO NPs doses determined in the MTT test provided faster wound closure in in-vitro conditions compared to the DMSO group. Biochemical analyses showed that inflammation and oxidative status decreased, while antioxidant levels increased in ZnO NPs groups. Immunohistochemical analyses showed increased expression levels of Bek/FGFR2, IGF, and TGF-β associated with wound healing. The findings reveal the antimicrobial effect of ZnO nanoparticles obtained using Capparis spinosa L. extract in vitro and their potential applications in wound healing.

Antibacterial Activity of Zinc Oxide Nanoparticles Loaded with Essential Oils.

One major problem with the overuse of antibiotics is that the microorganisms acquire resistance; thus the dose must be increased unsustainably. To overcome this problem, researchers from around the world are actively investigating new types of antimicrobials. Zinc oxide (ZnO) nanoparticles (NPs) have been proven to exhibit strong antimicrobial effects; moreover, the Food and Drugs Administration (FDA) considers ZnO as GRAS (generally recognized as safe). Many essential oils have antimicrobial activity and their components do not generate resistance over time. One of the drawbacks is the high volatility of some components, which diminishes the antimicrobial action as they are eliminated. The combination of ZnO NPs and essential oils can synergistically produce a stronger antimicrobial effect, and some of the volatile compounds can be retained on the nanoparticles' surface, ensuring a better-lasting antimicrobial effect. The samples were characterized with X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-Vis), and thermal analysis (TG-DSC) coupled with analysis of evolved gases using FTIR. The ZnO NPs, with a size of ~35 nm, exhibited a loading between 1.44% and 15.62%-the lower values were specific for limonene-containing oils (e.g., orange, grapefruit, bergamot, or limette), while high values were obtained from cinnamon, minzol, thyme, citronella, and lavender oils-highlighting differences among non-polar terpenes and alcohol or aldehyde derivatives. The antibacterial assay indicated the existence of a synergic action among components and a high dependency on the percentage of loaded oil. Loaded nanoparticles offer immense potential for the development of materials with specific applications, such as wound dressings or food packaging. These nanoparticles can be utilized in scenarios where burst delivery is desired or when prolonged antibacterial activity is sought.

Evaluation of Activity of Zinc Oxide Nanoparticles on Human Rotavirus and Multi-Drug Resistant Acinetobacter Baumannii.

Rotaviruses are the cause of acute gastroenteritis and severe diarrheal diseases in children worldwide. Children under the age of five are more susceptible to rotavirus infections. Due to such as the lack of effective drugs and supportive therapy only, the development of new antiviral agents against rotaviruses. Multi-drug-resistant Acinetobacter baumannii is also one of the most challenging Gram-negative bacteria to control and treat due to its antibiotic resistance, particularly in intensive care units. This study aimed to investigate the activity of zinc oxide nanoparticles against human rotavirus and multi-drug resistant Acinetobacter baumannii. The standard 50% tissue culture infectious dose method and the real-time polymerase chain reaction assay were used to investigate the effects of zinc oxide nanoparticles on rotaviruses. The well diffusion and the minimum inhibitory concentration method were used to assess the antibacterial activity of zinc oxide nanoparticles against Acinetobacter baumannii. 300 μg/ml of zinc oxide nanoparticles demonstrated the highest anti-rotavirus effects, resulting in a 3.16 logarithmic decrease in virus infectious titer, and a four-unit increase in the cycle threshold value of the real-time polymerase chain reaction assay compared to the untreated control (P value <0.001 and P value = 0.005, respectively). The diameter of the inhibition zone of zinc oxide nanoparticles solution against Acinetobacter baumannii was 17 mm. The minimum inhibitory concentration results of the zinc oxide nanoparticles solution against Acinetobacter baumannii was 1.56 mg/ml. Our findings showed that zinc oxide nanoparticles could be considered a promising antimicrobial compound.

Green Synthesis of Zinc Oxide Nanoparticles Using Chamomile and Green Tea Extracts and Evaluation of Their Anti-inflammatory and Antioxidant Activity: An In Vitro Study.

Background An important field of study in contemporary material science is the synthesis of metallic nanoparticles. The wide range of uses for zinc nanoparticles in industries like diagnosis and antimicrobial catalysis has sparked particular interest in them. Plant extracts are used to synthesize zinc nanoparticles, opening up a wide range of potential applications. Hence, the current study aims to demonstrate the anti-inflammatory and antioxidant activity of zinc oxide nanoparticles mediated by green tea and chamomile tea combination. Materials and methods Leaves of green tea and chamomile tea were combined in a ratio of 1 gram each. To make a 1-molar solution of the extract, the weighted extracts were thoroughly mixed with 100 ml of distilled water in conical flasks. To synthesize nanoparticles, a magnetic stirrer and an orbital shaker were used alternately with an extract of chamomile and green tea, 0.016 g of zinc oxide, and 90 ml of distilled water at 900 rpm. By using an albumin denaturation assay, the synthesized nanoparticles' anti-inflammatory activity was assessed. Bovine serum albumin (BSA) and egg albumin (EA) were the reagents used in the assay. The antioxidant activity of zinc oxide nanoparticles, which is mediated by chamomile and green tea, was determined using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and H2O2 (hydrogen peroxide) radical scavenging assays. An independent sample t-test was done to compare the anti-inflammatory and antioxidant potentials of zinc oxide nanoparticles mediated by green tea and chamomile tea combination and control using SPSS Statistics version 22.0 software (IBM Corp. Released 2013. IBM SPSS Statistics for Windows, Version 22.0. Armonk, NY: IBM Corp.), and any p-value less than 0.05 was considered statistically significant. Results In this study, the anti-inflammatory activity and antioxidant activity were assessed at variable concentrations of the reaction mixture. The combination of chamomile and green tea extracts mediated by zinc oxide nanoparticles at 50μl concentration showed the maximum anti-inflammatory activity and antioxidant activity at 87% inhibition, respectively. Conclusion Both assays successfully demonstrated better anti-inflammatory and antioxidant activity of zinc oxide nanoparticles mediated by chamomile and green tea combination when compared to control and, therefore, could be evaluated as a potential therapeutic agent.

Antifungal properties and phytotoxicity of ZnO nanoparticles – a genotypic dependent effect

Pyricularia oryzae, the causal agent of rice blast disease, is a serious threat to rice. It reduces the yield and quality of rice. Agrofungicide used to control rice blast is harming the environment and human health. Safer alternative is needed. This study aimed to investigate the antifungal activity of zinc oxide nanoparticles (ZnO NPs) against P. oryzae of Sarawak, and its phytotoxicity towards Sarawak rice. Solvothermal sysnthesis method was used to synthesize two sizes of ZnO NPs (∼20 nm and ∼40 nm). ZnO NPs showed inhibition effect on P. oryzae tested and the effect was isolate dependent. The effect increased along with the concentration increment of ZnO NPs. ZnO NPs were found not affecting the seed germination rate, but on the shoot and root development. The effect varies at different concentration treatments of ZnO NPs. Landrace/genotype dependent phytotoxicity effect of ZnO NPs was observed.

An evaluation of the biological activity of zinc oxide nanoparticles fabricated from aqueous bark extracts of Acacia nilotica

The phyto nanotechnology strategy was executed for the genesis of zinc oxide nanoparticles by applying bark aqueous extract of Acacia nilotica (AN-ZnO NPs). The AN-ZnO NPs emergence was substantiated through a distinct peak at 350 nm in the ultraviolet–visible spectroscopy. The fourier transform infrared spectroscopy exposed the phyto-organic moieties engaged as reduction and stabilization factors in fabricating nanoparticles. The crystalline trait, elemental proportions, spherical and hexagonal geometry of AN-ZnO NPs was witnessed by X-ray diffraction, energy-dispersive X-ray analysis and scanning electron microscopy. The high-resolution transmission electron microscopic technique provided the average size of 35 nm. AN-ZnO NPs presented larger inhibition zone against Candida albicans (22.7 ± 0.32 mm) at 40 µg/mL as an effectual fungicidal agent. Execution of in vitro antiradical scavenging assay of AN-ZnO NPs applying 2,2-diphenyl-1-picrylhydrazyl (DPPH), nitric oxide (NO), hydroxyl radical (OH–), 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) displayed radical scavenging trait with the minimum inhibitory concentration (IC50) of 34.54 µg/mL, 38.0 µg/mL, 41.34 µg/mL, and 35.41 µg/mL, respectively. Cytotoxic feature against MCF-7 cell line was in a dose-manner with IC50 value of 37.15 µg/mL in addition to apoptotic proteins expressions were displayed by AN-ZnO NPs. An appreciable larvicidal role of AN-ZnO NPs was rendered against Anopheles stephensi with LD50 (0.31 ppm) and LD90 (0.59 ppm), besides acetylcholinesterase inhibition. Further, biofilm origination was remarkably ceased by the Staphylococcus aureus and Klebsiella pneumoniae, respectively. All our experimented reports on AN-ZnO NPs attested the credible applicability of ZnO NPs in biomedical care for health troubles.

Antiviral Activity of Zinc Oxide Nanoparticles against SARS-CoV-2.

The highly contagious SARS-CoV-2 virus is primarily transmitted through respiratory droplets, aerosols, and contaminated surfaces. In addition to antiviral drugs, the decontamination of surfaces and personal protective equipment (PPE) is crucial to mitigate the spread of infection. Conventional approaches, including ultraviolet radiation, vaporized hydrogen peroxide, heat and liquid chemicals, can damage materials or lack comprehensive, effective disinfection. Consequently, alternative material-compatible and sustainable methods, such as nanomaterial coatings, are needed. Therefore, the antiviral activity of two novel zinc-oxide nanoparticles (ZnO-NP) against SARS-CoV-2 was investigated in vitro. Each nanoparticle was produced by applying highly efficient "green" synthesis techniques, which are free of fossil derivatives and use nitrate, chlorate and sulfonate salts as starting materials and whey as chelating agents. The two "green" nanomaterials differ in size distribution, with ZnO-NP-45 consisting of particles ranging from 30 nm to 60 nm and ZnO-NP-76 from 60 nm to 92 nm. Human lung epithelial cells (Calu-3) were infected with SARS-CoV-2, pre-treated in suspensions with increasing ZnO-NP concentrations up to 20 mg/mL. Both "green" materials were compared to commercially available ZnO-NP as a reference. While all three materials were active against both virus variants at concentrations of 10-20 mg/mL, ZnO-NP-45 was found to be more active than ZnO-NP-76 and the reference material, resulting in the inactivation of the Delta and Omicron SARS-CoV-2 variants by a factor of more than 106. This effect could be due to its greater total reactive surface, as evidenced by transmission electron microscopy and dynamic light scattering. Higher variations in virus inactivation were found for the latter two nanomaterials, ZnO-NP-76 and ZnO-NP-ref, which putatively may be due to secondary infections upon incomplete inactivation inside infected cells caused by insufficient NP loading of the virions. Taken together, inactivation with 20 mg/mL ZnO-NP-45 seems to have the greatest effect on both SARS-CoV-2 variants tested. Prospective ZnO-NP applications include an antiviral coating of filters or PPE to enhance user protection.

Green Synthesis, Characterization and Antimicrobial Activity of Zinc Oxide Nanoparticles from Leave Extracts of Ziziphus spina-christi Plant

Green Synthesis, Characterization and Antimicrobial Activity of Zinc Oxide Nanoparticles from Leave Extracts of Ziziphus spina-christi Plant

Synthesis, Characterization and Biological Activities of Zinc Oxide Nanoparticles Derived from Secondary Metabolites of Lentinula edodes.

Zinc oxide nanoparticles (ZnO NPs) are the second most prevalent metal oxide, owing to their characteristics of low cost, safe, and easily prepared. ZnO NPs have been found to exhibit unique properties which show their potential to be used in various therapies. Numerous techniques have been devised for the manufacture of zinc oxide because it is one of the nanomaterials that has received major research interest. Mushroom sources are proven to be efficient, ecologically friendly, inexpensive, and safe for humankind. In the current study, an aqueous fraction of methanolic extract of Lentinula edodes (L. edoes) was used to synthesize ZnO NPs. The biosynthesis of ZnO NPs was achieved by using the reducing and capping capability of an L. edodes aqueous fraction. Bioactive compounds from mushroom, such as flavonoids and polyphenolic compounds, are used in the green synthesis process to biologically reduce metal ions or metal oxides to metal NPs. Biogenically synthesized ZnO NPs were further characterized by using UV-Vis, FTIR, HPLC, XRD, SEM, EDX, zeta sizer and zeta potential analyses. The FTIR showed the functional group at the spectra in the range 3550-3200 cm-1 indicated the presence of the hydroxyl (OH) group, while bands in the range 1720-1706 cm-1 indicated C=O carboxylic stretches bonds. Furthermore, the XRD pattern of ZnO NPs created in the current study was found to be nanocrystals which are hexagonal. The SEM analysis of ZnO NPs showed spherical shapes and size distributions in the range 90-148 nm. Biologically synthesized ZnO NPs have substantial biological activities including antioxidant, antimicrobial, antipyretic, antidiabetic and anti-inflammatory potential. Biological activities showed significant antioxidant (65.7 ± 1.09), antidiabetic (85.18 ± 0.48), and anti-inflammatory potential (86.45 ± 0.60) at 300 µg inhibition in paw inflammation of (1.1 ± 0.06) and yeast-induced pyrexia (97.4 ± 0.51) at 10 mg in a dose-dependent manner. The outcomes of this research indicated that ZnO NPs significantly reduced inflammation and have the ability to scavenge free radicals and prevent protein denaturation, while also indicating their possible use in food and nutraceutical applications to treat various ailments.

Antimicrobial impacts of zinc oxide nanoparticles on Shiga toxin-producing Escherichia coli (serotype O26)

Abstract The antibacterial activity of zinc oxide nanoparticles (ZnO NPs) has received significant attention worldwide due to the emergence of multidrug-resistant microorganisms. Shiga toxin-producing Escherichia coli is a major foodborne pathogen that causes gastroenteritis that may be complicated by hemorrhagic colitis or hemolytic uremic syndrome. Therefore, this study aimed to evaluate the antimicrobial effect of ZnO NPs against E. coli O26 and its Shiga toxin type 2 (Stx2). Multidrug resistance phenotype was observed in E. coli O26, with co-resistance to several unrelated families of antimicrobial agents. Different concentrations of ZnO NPs nanoparticles (20 nm) were tested against different cell densities of E. coli O26 (108, 106 and 105 CFU/ml). The minimum inhibitory concentration (MIC) value was 1 mg/ml. Minimum bactericidal concentration (MBC) was 1.5 mg/ml, 2.5 mg/ml and 3 mg/ml, respectively, depending on ZnO NPs concentrations and bacterial cell density. Results showed a significant (P≤0.05) decrease in Stx2 level in a response to ZnO NPs treatment. As detected by quantitative real-time PCR, ZnO NPs down-regulated the expression of the Stx2 gene (P≤0.05). Moreover, various concentrations of ZnO NPs considerably reduced the total protein content in E. coli O26. There was a significant reduction in protein expression with increased ZnO NPs concentration compared to the non-treated control. Scanning electron micrographs (SEM) of the treated bacteria showed severe disruptive effects on E. coli O26 with increasing ZnO NPs concentration. The results revealed a strong correlation between the antibacterial effect and ZnO NPs concentrations. ZnO NPs exert their antibacterial activities through various mechanisms and could be used as a potent antibacterial agent against E. coli O26.

Antibacterial and antifungal activity of zinc oxide nanoparticles produced by Phaeodactylum tricornutum culture supernatants and their potential application to extend the shelf life of sweet cherry (Prunus avium L.)

In the current work, zinc oxide nanoparticles (ZnONPs) synthesized by the cell-free supernatant of Phaeodactylum tricornutum cultures were first examined for their physicochemical and antimicrobial proprieties. They were then applied as spray coating on the surface of fresh sweet cherries to evaluate their efficacy on quality maintenance of the fruit over 10 days of storage at 25 °C. Synthesized nanoparticles showed a large-scale inhibitory effect against Escherichia coli (ATCC 25922), Staphylococcus aureus MRSA (ATCC 43300) and Candida albicans (ATCC 14053) with minimum inhibitory concentrations (MIC) ranged between 0.078 and 0.156 mg/mL. Furthermore, ZnONPs at 100–1000 mg/L effectively inhibited mycelia growth of Mucor heimalis, a causative agent of Mucor rot in sweet cherries. The results also indicated that ZnONPs significantly delayed the changes of visual and biochemical attributes of the fruit. Compared to untreated control, coated cherries with ZnONP at a concentration of 500 mg/L showed very small change in moisture and total sugar content. Therefore, all coated fruits exhibited less decay rates. In addition, spray coating with ZnONPs had a positive effect on maintaining suitable amounts of ascorbic acid (29.74 mg/100 g FW), polyphenols (579.2 μg/g FW) and flavonoids in the fruits (1991.87 μg/g FW). Data from this study showed 5.11% and 11.63%, increase in flavonoid content and antioxidant activity in the fruits coated with 500 mg/L ZnONPs, respectively, at the end of storage. These data together suggest that green ZnONPs-based coating is one of the safest and effective ways to preserve commercial fruits for prolonged storage.

Enhancing photocatalytic activity of zinc oxide nanoparticles by a ‎non-thermal atmospheric pressure plasma

Enhancing photocatalytic activity of zinc oxide nanoparticles by a ‎non-thermal atmospheric pressure plasma

Characterization and investigation of antioxidant and antimicrobial activity of zinc oxide nanoparticles prepared using leaves extract of Nyctanthes arbor-tristis

Due to the emergence of multidrug resistance, the occurrence of microbial infections has increased by several times during the last decade. In addition, a significant challenge in green nanotechnology is to develop an environment-friendly and simple route to produce different metal oxide nanoparticles. Hence, the goal of the present study is to synthesize and evaluate the antimicrobial efficacy of Nyctanthes arbor-tristis (NA) leaves extract decorated zinc oxide nanoparticles (ZnO-NA). The structural, morphological, and optical assessments of the ZnO-NA nanoparticles were carried out via Field emission scanning electron microscopy (FE-SEM), Powder X-ray diffraction (PXRD), UV–Visible spectroscopy, and Fourier transform infrared spectroscopy (FT-IR). The interaction of as synthesized ZnO-NA with bacteria was confirmed by energy dispersive spectroscopic (EDS) analysis. The PXRD pattern revealed the hexagonal wurtzite crystalline structure whereas from UV–Visible spectroscopy, obtained absorbance peak at 370 nm confirmed the formation of ZnO-NA. The interactions of the phytoconstituents present in the aqueous extract of Nyctanthes arbor-tristis with zinc oxide nanoparticles were established from the spectra of FT-IR analysis. Furthermore, the FE-SEM micrographs revealed thenanotilesshape of the synthesized ZnO-NA with the rough surface having nanocracks. The thickness and length of these nanotiles were calculated at approximately 75–150 nm and 550–600 nm respectively.The intercept and slope values obtained from this plot were 0.00675 and 0.01013 respectively. The crystallite size obtained from the Williamson-Hall (W-H) plot was 21.45 nm. The DPPH (2, 2-diphenyl-1-picryl-hydrazyl-hydrate) assay was employed for studying the antioxidant activity of the leaves extract of the Nyctanthes arbor-tristis plant. The IC50 value was observed to be 125 µg/mL. Besides, the antimicrobial efficacy of the green synthesized ZnO-NA nanoparticles was reported against two bacterial strains, Staphylococcus aureus (gram-positive) and Acinetobacter baumannii (gram-negative) bacteria using an agar well diffusion test and a micro broth dilution assay. Maximum zone of inhibition was obtained 7 ± 0.1 mm against Staphylococcus aureus and 0.5 ± 0.05 mm and 0.5 ± 0.10 mm against Acinetobacter baumannii respectively. The minimum inhibitory concentration (MIC) values were observed at 12.5 mg/mL for Staphylococcus aureus and 3.125 mg/mL for Acinetobacter baumannii, respectively. Therefore, the results of MIC values suggested that green synthesized ZnO-NA nanoparticles could be used as an alternative drug in the medical field to treat bacterial infections..