Presence Of ZnO Nanoparticles Research Articles

Green Synthesis, Characterization and Pharmaceutical Applications of Biocompatible Zinc Oxide Nanoparticles Using Heliotropium rariflorum Stocks

Background: Zinc oxide nanoparticles are safe, non-toxic, and biocompatible. These NPs are used in food packaging materials, self-cleaning glass, ceramics, deodorants, sunscreens, paints, coatings, ointments, lotions, and as preservatives. This study explored the biological potential of ZnO nanoparticles synthesized using H. rariflorum. Methods: In vitro antibacterial and antifungal activities against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, Candida albicans, Penicillium notatum, Aspergillus flavus, Aspergillus niger and Aspergillus solani were determined. Antioxidant activity was explored using the DPPH radical scavenging method. In vivo analgesic, antipyretic and sedative potential of synthesized nanoparticles was investigated using a mouse model. Results: SEM with various magnification powers showed that some particles were spherical while some were aggregated, flake-shaped, and hexagonal with rough and irregular surfaces. The EDX analysis revealed Zn (12.63%), O (22.83%) and C (63.11%) with trace quantities of Si (0.40%), Ca (0.54%) and P (0.49%). The XRD pattern indicated an amorphous state, with no peaks observed throughout the spectrum. The UV–visible spectrophotometry revealed a characteristic absorption peak at 375 nm, indicating the presence of ZnO nanoparticles. Fourier Transform Infrared Spectroscopy (FTIR) displayed several small peaks between 1793 and 2370 cm−1, providing evidence of the presence of different kinds of organic compounds with different functional groups. ZnO-NPs showed dose-dependent antibacterial and antifungal potential against all strains. Staphylococcus aureus and Candida albicans were the most susceptible strains. The nanoparticles exhibited a maximum antioxidant effect of 85.28% at 100 μg/mL. In this study, the acute toxicity test showed no mortality, and normal behavior was observed in mice at ZnO-NP doses of 5, 10, and 20 mg/kg. For analgesic and antipyretic activities, a two-way ANOVA revealed that dose, time, and the interaction between dose and time were significant. In contrast, the samples had a non-significant effect on sedative activity. Conclusions: This innovative study suggests a potential use of plant resources for managing microbes and treating various diseases, providing a scientific basis for the traditional use of H. rariflorum.

By-product distribution and cytotoxicity assessment of ZnO-assisted photocatalytic degradation of reactive blue 250 dye

This research examined the effectiveness and feasibility of utilizing ultraviolet (UV) assisted photo-catalysis to treat wastewater effluents from textile production containing reactive blue 250 (RB 250) dye. Molecular oxygen and active species like O2•−, HO2•, H2O2 and •OH play crucial roles in the degradation process. Additionally, the degradation of dyes is influenced by several factors, including dye concentration, duration of UV irradiation, pH levels, concentration of H2O2, and the catalyst. The concentration of H2O2 and catalyst dose for the decolorization was studied at 0.6 mL and 0.5 g respectively. The discoloration was higher at low dye concentration, high H2O2 concentration, acidic conditions and high catalyst concentration. The maximum degradation (97 %) of RB 250 dye was obtained in the presence of zinc oxide nanoparticles within 90 min. The extent of decolorization of the dye was determined by UV–Vis spectroscopy. Fourier transform infrared spectroscopy (FTIR) was employed to analyze the changes in functionalities after degradation. The disappearance of characteristic peaks associated with specific groups within the dye molecule confirmed the extensive degradation of RB 250 dye. LCMS analysis was conducted to examine the intermediates and a mechanistic degradation pathway was subsequently proposed. The cytotoxicity of the irradiated dye samples was evaluated through a hemolytic test both pre and post-treatment. The findings suggest that the UV/H2O2/ZnO treatment represents a promising approach for effectively degrading RB 250 dye.

Cloud point extraction and characterization of zinc oxide nanoparticles isolated from infant milk formulas

The increasing presence of nanoparticles in food products, especially in those consumed by sensitive populations like infants, raises justified health concerns. The presence of zinc oxide nanoparticles (ZnO-NPs) in three different commercial infant milk formulas were analyzed. In addition, one maternal food supplement was included in this study. Notably, existing regulations lack specificity regarding the size distribution of nanoparticles (NPs) and the maximum permissible concentrations in commercial infant products. Except in one sample, the total zinc content exceeded the reported amount in the nutritional label, which varied from 34 to 119 µg/g. This work validated the cloud point extraction (CPE) technique for the effective isolation of ZnO-NPs from the selected products. CPE was then used to evaluate the ZnO-NPs concentrations in commercially available infant formulas and maternal supplements. Using inductively coupled plasma optical emission spectrometry (ICP-OES), the ZnO-NPs and total Zn concentrations were determined. The ZnO-NPs concentration ranged from 16 to 39 µg/g, representing a considerable portion of the total zinc content. Transmission electron microscopy (TEM) analysis indicated the presence of nanoparticles with an average diameter of 6.3 nm. The NPs size could determine their cell internalization, and thus, the potential cytotoxic effects are discussed. These findings underscore the need for rigorous isolation and quantification of nanoparticles from infant milk formulas, and as an inevitable first step for in vitro and in vivo toxicity studies to address the potential health impact of nanoparticles in food products.

Synthesis of ZnO/Poly(Styrene‐co‐Methacrylic Acid) Hybrid Polymer Particles for Enhanced UV‐Visible Photodegradation of Methylene Blue

AbstractIn this study, a series of submicron‐sized functional polymer particles poly(Sty‐co‐MAA) with variable methacrylic acid (MAA) content were prepared by soap‐free emulsion polymerization of styrene (Sty), methacrylic acid (MAA), and ethylene glycol dimethacrylate (EGDMA). The number‐average diameters of polymer particles (Dn) were in the range of 0.11 to 0.19 μm. A decrease in particle size was observed with increasing the molar ratio of MAA comonomer in the recipe. ZnO/poly(Sty‐co‐MAA) hybrid polymer particles were prepared by seeded emulsion copolymerization in presence of zinc oxide nanoparticles (ZnO NPs) as seed particles synthesized using Citrus lemon aqueous leaf extract. Scanning electron microscopy (SEM), transmission electron microsphere (TEM), X‐Ray Diffraction (XRD), and Fourier transformed infra‐red (FT‐IR) analysis were performed to characterize polymer particles. The crystalline size of ZnO NPs and ZnO/poly(Sty‐co‐MAA) hybrid polymer particles calculated from XRD analysis were 20.75 and 29.85 nm, respectively. These hybrid polymer particles were applied as photocatalyst in the photodegradation of methylene blue (MB) dye under UV irradiation, which showed high catalytic activity with degradation efficiency of 85.70 % at room temperature compared to bare ZnO NPs.

The effect of zinc oxide nanoparticles on the growth and development of Stevia plants cultured in vitro

Stevia (Stevia rebaudiana Bertoni) is an essential herbal plant used as a sweetener. The demand for stevia is growing due to its low caloric and medicinal value, hence the need for a more thorough investigation of its nutritional and biological properties. Nanoparticles of metal oxides have been found to have broad applications in agriculture for the stimulation of plant growth and development. The study aimed to assess the effect of various zinc oxide nanoparticles (ZnONPs) concentrations on stevia plants’ quantitative and qualitative traits obtained in in vitro cultures. Micropropagation of two stevia varieties, Candy and Morita, was carried out using explants of shoot tips placed on MS medium supplemented with 1.0 mg dm–3 BA and 0.1 mg dm–3 IBA and with ZnONPs at concentrations of 0 (control), 10, 20, 30 and 40 mg dm–3. The obtained results indicated that high concentrations of ZnONPs stimulated the propagation of shoots. On the other hand, they negatively influenced shoot length, root number and length, and the fresh weight of the plantlets. The presence of zinc oxide nanoparticles in the medium increased the potassium, calcium, magnesium, and zinc content while decreasing the sodium and iron content in the regenerated stevia plantlets. The total phenolic content in the Candy variety was higher in the treatments with ZnONPs than in the control plants, while it was varied in the Morita variety. In both varieties, total antioxidant content measured by the ABTS method showed significantly higher in the treatments with 20–30 mg dm–3 ZnONPs than in the control. The content of chlorophyll a, chlorophyll b and chlorophyll a + b in the Morita variety was higher in the treatments with 10 and 20 mg dm–3 ZnONPs than in the control. On the other hand, high concentrations of ZnONPs negatively affected the content of carotenoids in both varieties. The study showed that stevia plants obtained in in vitro cultures on control media and media containing ZnONPs had a high content of valuable minerals, phytocompounds with antioxidant properties, and photosynthetic pigments.

Fast and effective hydroquinone adsorption by poly (2-dimethylaminoethyl methacrylate)/zinc oxide nanocomposite hydrogel in textile wastewater treatment

ABSTRACT Hydroquinone, a widely used phenolic compound, poses significant health and environmental risk and must be removed from wastewater. In this study, a novel adsorbent was developed for the removal of hydroquinone from aqueous solutions through the in-situ polymerisation of 2-(dimethylamino)ethyl methacrylate (DMAEMA) in the presence of zinc oxide nanoparticles (ZnO NPs). The kinetics of equilibrium swelling in deionised water (DI) and the effect of pH on the swelling behaviour were investigated. The structure of the nanocomposite hydrogel was analysed using FTIR, XRD, FESEM, EDX, TEM, and BET analysis. Various factors affecting the adsorption process, such as solution pH (2–12), initial concentration (25–200 mg/L), adsorbent dosage (4.0–80 mg/100 mL), NaCl concentration (0.1–1.0 mol/L), and temperature, were also investigated. The adsorption capacity of hydroquinone and the removal efficiency of PDMAEMA@ZnO reached 455 mg/g and 91%, respectively, at pH 11 within 15 minutes. Furthermore, PDMAEMA@ZnO showed a high removal efficiency of 99.47% in tests with real wastewater. Reusability studies showed that the adsorbent retained its ability to remove hydroquinone after four regeneration cycles. The adsorption data were well described by the pseudo-second order and Langmuir models. The thermodynamic parameters indicated that the adsorption process is spontaneous and endothermic. Therefore, the adsorbent, has considerable industrial potential as it quickly and efficiently adsorbs phenolic impurities such as hydroquinone from real textile wastewater.

Influence of Zinc Oxide Nanoparticles in In Vitro Culture and Bacteria Bacillus thuringiensis in Ex Vitro Conditions on the Growth and Development of Blackberry (Rubus fruticosus L.)

The blackberry, valued for its delicious fruit, has gained attention for its medicinal bioactive compounds. In vitro cultivation methods, including nanoparticle enhancement, are increasingly chosen due to their advantages over traditional propagation techniques. We tested the effect of commercial zinc oxide nanoparticles (ZnONPs) on the growth and development of blackberry (Rubus fruticosus L.) of the Navaho variety in an in vitro culture on MS medium supplemented with 0.6 mg dm−3 BA, 0.1 mg dm−3 IBA, 0.01 mg dm−3 GA3, and various concentrations of zinc oxide nanoparticles: 0 (control), 10, 20, 30, and 40 mg dm−3. The morphological features of the plantlets were assessed two and three months after the start of the culture. Selected biological characteristics of the plantlets were determined. The values of the morphological and biological parameters assessed in the plantlets from in vitro culture depended on the concentration of ZnONPs in the medium. Increasing the concentration of ZnONPs negatively affected the number and length of shoots and roots and the fresh weight of the plantlets. The total phenolic content in the plantlets from the treatments with ZnONPs was lower than in the control plants, but the total antioxidant capacity as measured by the ABTS method was higher. The content of chlorophyll a, chlorophyll b, total chlorophyll, and carotenoids in the blackberry plantlets decreased at higher concentrations of ZnONPs in the medium. The addition of zinc oxide nanoparticles increased the zinc content and reduced the iron content in the blackberry plantlets. Concentrations of 10–30 mg dm−3 ZnONPs increased the concentrations of potassium, calcium, magnesium, zinc, manganese, and copper, while at the highest concentration of 40 mg dm−3 ZnONPs, the concentrations of these minerals were similar to the control, except for a lower content of calcium and manganese. The plantlets from the in vitro culture growing in the presence of ZnONPs were acclimatized to ex vitro conditions in control soil and soil inoculated with Bacillus thuringiensis. Bacteria added to the ex vitro substrate favourably influenced the growth and development of the shoots and roots of the blackberry plants and their fresh weight.

Biopolymeric fibers prepared by centrifugal spinning blended with ZnO nanoparticles for the treatment of Acne vulgaris

Acne vulgaris is a serious dermatological disease affecting a significant part of the population. Currently, available therapeutics are effective only at high concentrations, which has a negative environmental and economic impact. In particular, ZnO nanoparticles (NPs) have a great potential in various biomedical applications due to their specific properties and antibacterial/antiviral activity. In this study, biomedically approved ZnO NPs with distinct diameter were used as the active therapeutic modality to treat acne-causing pathogens. For the first time, we show the utilization of ZnO NPs that were evenly distributed within centrifugally spun fiber carriers. Upon application on the skin, ZnO NPs can sustainably release and have profound antibacterial activity at lower therapeutic concentrations. Fibers were made using innovative centrifugal spinning procedure from natural polymers - gum arabic and pullulan - that are known for their biocompatibility. Different amount of ZnO NPs (from 0.03 to 4.5 wt.% related to the dry mass) was added into the spinning polymer solution, either in a form of a dry powder or as a dispersion containing NPs and isopropyl myristate. The resulting fibers were subsequently characterized for morphology and presence of ZnO NPs by Scanning Electron Microscopy and Energy-Dispersive X-ray fluorescence spectrometry. The materials were thoroughly assessed for their antibacterial activity against Cutibacterium acnes and Staphylococcus epidermidis, which are major opportunistic pathogens causing acne. The combination of two types of nanomaterials, namely active nanoparticles and fiber carriers, proved to be very promising and bear a great potential for the treatment of these diseases.

Zinc oxide nanoparticles exhibit anti-cancer activity against human cell lines

Zinc oxide nanoparticles have garnered tremendous interest in bio and nanomedical applications and more so in cancer research. In the present work, zinc oxide nanoparticles were synthesized using the solution combustion method and characterized by UV–vis spectroscopy, FTIR, XRD, SEM and EDX. The infrared spectrum of the synthesized nanoparticles had a peak at 547 cm−1 which indicated the elongation frequency of the zinc bond to oxygen. The XRD spectrum was confirmed with the ICDD Data Card No: 36-1451 for zinc oxide and the average size of zinc oxide nanoparticles was estimated to be 17.51 nm. Scanning electron microscopy confirmed the presence of zinc oxide nanoparticles as Zincite with a hexagonal structure having an average diameter of 30.95 nm. The DNA binding interactions of the nanoparticles were studied using the absorption titration method. The nanoparticles could bind via the non-intercalation mode with a binding efficiency of 3.563×105 M−1. The synthesized zinc oxide nanoparticles exhibited cytotoxic activity against the mammalian cancer cell lines tested with the calculated IC50 values being 3.66 µgmL−1 for MCF-7 (Breast), 2.91 µgmL−1 for LN-18 (Glioblastoma–Brain), 23.14 µgmL−1 for A-549 (Lung) and 94.33 µgmL−1 for SHSY-5Y (Neuroblastoma–Bone). The highest cell death was observed for LN-18 glioblastoma cells of the brain. The study demonstrated a simple and conventional method of synthesis of zinc oxide nanoparticles that have demonstrated anticancer activity as evidenced by the in vitro cell viability assays. The outcome of this study could be applied to develop zinc oxide nanoparticles as anticancer agents with further validation in vivo.

Structural and functional premise of transport protein transthyretin in the sight of silver and zinc oxide nanoparticles through atomistic simulations

Drug transport and distribution in excessive concentrations or at unspecified locations within the human body has a negative impact which leads to further complications. Multiple methodologies have been devised to facilitate precise drug delivery, ensuring the desired quantity reaches the intended target site. Nanoparticle-based drug delivery has emerged as a promising and advanced method. However, there remains a significant scope for deeper mechanistic understanding concerning the protein-nanoparticle corona, their interactions, and the diverse effects of nanoparticles at an atomistic scale. Through the analysis of protein-nanoparticle interactions, it is possible to gain insight into the drug delivery potential of nanoparticles. In this study, we have evaluated how Silver and Zinc Oxide Nanoparticles (AgNP/ ZnONP) affect the structure and function of Transthyretin, a serum transport protein with clinical significance. In the context of the structure–function relationship, our biophysical modeling indicates that Silver Nanoparticles (AgNP) interact with Transthyretin without causing changes in its secondary or tertiary structure. This interaction is projected to have no discernible impact on the protein's function. Yet, in the presence of Zinc Oxide Nanoparticles (ZnONP), Transthyretin experiences considerable changes in its secondary and tertiary structure, which shall lead to disruption of its normal function. This study suggests the potential preference for employing AgNP over ZnONP for transporting conjugated medicines or small molecules. Moreover, Transthyretin's capability to traverse the blood–brain barrier positions it as a promising candidate for nanoparticle-assisted drug delivery across this physiological barrier.

Degradation of Rice Straw in the Presence of ZnO Nanoparticles and Cellulase Production with the Help of Streptomycetes Species

Degradation of Rice Straw in the Presence of ZnO Nanoparticles and Cellulase Production with the Help of Streptomycetes Species

Fabrication and Characterization of Eco-Friendly Polystyrene Based Zinc Oxide-Graphite (PS/ZnO-G)

One of the most significant environmental challenges nowadays is the rising manufacturing of non-biodegradable polymer wastes like polystyrene. In order purpose of manufacture environmentally friendly polystyrene that easily decomposes, a solvent approach was used to create polystyrene based zinc oxide- graphite composites. The surface morphology and materials contained in the modified polystyrene were evaluated by scanning electron microscopy-energy dispersive X-ray analysis to verify the dispersion and distribution of the nanoparticles by scanning electron microscopy and the material contents by energy dispersive X-ray analysis. While the crystal structure, chemical bonds, and functions were determined by X-ray Diffraction and Fourier transform infrared, no change in the chemical structure occurred in polystyrene. Thermogravimetric analysis was used to assess the thermal decomposition. And its results found that the temperature of the decomposition was 46.78° lower in zinc oxide and graphite-based polystyrene composites than in pure polystyrene. It came to light that the presence of zinc oxide nanoparticles causes phase separation and consequently impacts the thermal behaviour of graphite-based polystyrene composites. The phase separation was demonstrated by the Thermogravimetric curves showing two degrading steps. This satisfies the urgent demand to synthesize polystyrene that is eco-friendly and easy to thermally decomposition, as well as easy to recycle, which benefits both the environment and the commercial side.

Use of absorber plate built of ZnO/PVC/Bioactivation modified epoxy nanocomposites to improvement of double-effect Solar Distiller productivity analyzing the Energy, Exergo-environment and Enviro-economical

In this study, solar thermal desalination methods were developed to enhance the day to day efficiency of solar distillers by improving their portability and water purification properties. The performance of solar stills is highly contingent on environmental factors, making it essential to address these variables. To achieve this, a double-slope single basin solar distiller (DSBD) was upgraded by incorporating a partially coated absorber plate with ZnO/PVC/Bioactive nanocomposite (ZPBN), which was subsequently examined for its impact on drinking water production from multiple perspectives, including energy, exergy, environmental, and economic considerations. The ZPBN material was synthesized using the solvent casting technique, and its properties were comprehensively characterized through various analytical methods. X-ray diffraction (XRD) analysis revealed a regular crystalline lattice structure amidst an amorphous background, and scanning electron microscopy (SEM) images confirmed its surface performance. The presence of ZnO nanoparticles within the PVC and bioactive matrix imparted enhanced thermal characteristics to the DSBD, including higher temperatures, specific heats, and thermal stability compared to the ZPBN. The study demonstrated that the introduction of ZPBN significantly increased drinking water yield by up to 126% due to its enhanced absorption of solar energy. Furthermore, the energy efficiency of the DSBD improved by 0.44%, while its exergy efficiency decreased by 0.25% when compared to a conventional double slope single basin solar distiller (CDSBD) under the tropical climate conditions of Vijayawada, India. In terms of energy matrices, the ZPBN-coated basin area exhibited minimum and maximum energy payback times of 6.55 years and 0.15 years, respectively. Over its lifetime, the DSBD was found to reduce carbon dioxide emissions by 2.97 tonnes and offered the lowest cost per litre, amounting to $0.0360. The incorporation of ZPBN on the absorber plate within the DSBD resulted in excellent environmental and energy economies, with values of 4.640 kWh/$ and $83.210, respectively.

Low-cost ZnO incorporated carbonized nitrile butadiene rubber (NBR) as a relative humidity monitoring sensor

This paper presents the development and characterization of a sustainable humidity sensor that is both cost-effective and high performing. The sensor utilizes a composite material comprising conductive carbon derived from recycled Nitrile Butadiene Rubber (NBR) gloves and zinc oxide (ZnO). Among the various chemical compositions tested, the sensor with a carbon-to-zinc oxide (C:ZnO) ratio of 1:0 exhibited superior humidity-sensing performance. The study encompassed a broad spectrum of relative humidity levels, ranging from 5% to 95% at room temperature (25 °C) at an optimum frequency of 100 Hz. The sensor exhibited remarkable characteristics, including a minimal hysteresis of only 0.36%, indicating its ability to provide consistent and accurate readings. Moreover, the sensor demonstrated excellent long-term stability, ensuring reliable performance over extended periods. Additionally, the sensor showcased rapid and dependable sensing capabilities, with a response time of 18 s and a recovery time of 16 s. This indicates its ability to detect and recover from changes in humidity levels promptly. The composite material's high sensitivity to relative humidity variations can be attributed to the presence of zinc oxide nanoparticles (NPs), which have an affinity for water molecules and facilitate interaction. To assess its performance, the developed sensor was compared to most previous work in the literature and the results revealed that the proposed sensor exhibits comparable levels of accuracy and reliability. This work provides a simple, cost-effective strategy for fabricating high-performance humidity sensors by exploring waste materials like NBR.

Enhanced electrochemical detection of nitrobenzene using zinc oxide-carboxylated graphene oxide composite as sensor

This study focused on the electrochemical detection of nitrobenzene (NB) using a glassy carbon electrode (GCE) modified with carboxylated graphene oxide (c-GO) that contained zinc nanoparticles (ZnO@c-GO/GCE). ZnO@c-GO nanocomposite modified GCE structural studies using SEM, XRD, and XPS showed that ZnO nanoparticles were successfully incorporated into c-GO nanosheets. Through the cooperative action of c-GO nanosheets and ZnO nanoparticles, electrochemical studies using electrochemical impedance spectroscopy, cyclic voltammetry, and amperometry demonstrated that the presence of ZnO nanoparticles and c-GO facilitated electron transfer between the redox probe and the electrode surface. Results showed that ZnO@c-GO/GCE had a broad linear sensitivity range of 0.1091 μA/μM, a considerably low limit of detection of 0.013 μM, and a linear range of 100–3000 μM. The prepared real sample of industrial wastewater samples used in the study to determine the precision of the proposed sensor for NB determination revealed significant recovery values (over 94.50 %) and acceptable accuracy (RSD less than 4.21 %), indicating that ZnO@c-GO (2:3)/GCE can be used as a precise NB electrochemical sensor in environmental applications.

Preparation characterization and photocatalytic activity of SF-ZnO nanocomposite

This article describes the fabrication of zinc oxide nanoparticles (ZnO-NPs) incorporating silk fibroin (SF) nanocomposite and its characterization. The optical, structural and morphological features of fabricated nanocomposite film were reviewed by using UV–Visible spectroscopy (UV–Vis), X-ray diffraction measurement (XRD), field emission scanning electron microscopy (FE-SEM) with energy dispersive spectroscopy (EDS) experimental techniques. The UV–Vis absorption spectrum revealed presence of zinc oxide nanoparticles in the SF film with absorption peak at λ = 362 nm. The presence of zinc oxide nanoparticles in composite film was confirmed by diffraction peaks found at scattering angle at 2θ = 35.13°, 55.32°, 62.06°, 67.10° and 68.53° respectively. The FE-SEM study showed native SF has very smooth surface morphology, whereas the SF-ZnO nanocomposite film exhibited rough surface. The ZnO-NPs present in the sample were spherical in shape. Further, the photocatalytic activity of SF-ZnO-NCs film was evaluated by observing the photo-degradation of the textile dye methylene blue (MB) under UV-B light irradiation. The maximum degradation efficiency was nearly 84 % within 340 min. The results obtained suggested that SF-ZnO-NCs film could be used as a photocatalytic material in the treatment of textile waste water.

Insight into the responses of antibiotic resistance genes in microplastic biofilms to zinc oxide nanoparticles and zinc ions pressures in landfill leachate

Microplastic (MP) biofilms are hotspots of antibiotic resistance genes (ARGs) in landfill environment. MP biofilms in landfill leachate coexist with heavy metals and metallic nanoparticles (NPs) that considered to be the selective agents of ARGs. However, the effects of these selective pressures on ARGs in MP biofilms and their differences in MP-surrounding leachate have not been well understood. Herein, the changes of ARG abundances in MP biofilms and corresponding leachate under zinc oxide (ZnO) NPs and zinc ion (Zn2+) pressures were comparatively analyzed. The presence of ZnO NPs and Zn2+ promoted the enrichment of ARGs in MP biofilms, and the enrichment was more pronounced in ZnO NPs groups. ZnO NPs and especially Zn2+ mainly decreased the abundances of ARGs in leachate. The increase of integron abundances and reactive oxygen species production in MP biofilms implied the enhanced potential for horizontal transfer of ARGs under ZnO NPs and Zn2+ pressures. Meanwhile, the co-occurrence pattern between ARGs and bacterial genera in MP biofilms with more diverse potential ARG hosts was more complex than in leachate, and the enrichment of ARG-hosting bacteria in MP biofilms under ZnO NPs and Zn2+ pressures supported the enrichment of ARGs.

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.

Green synthesised ZnO nanoparticles from Plectranthus amboinicus plant extract: removal of Safranin- O and Malachite green dyes & anti-bacterial activity

ABSTRACT The synthesis of Zinc oxide nanoparticles using a plant-mediated approach is presented in this paper. The nanoparticles were successfully synthesised using the sulphate derivative of Zinc and plant extract of the indigenous medicinal plant Plectranthus amboinicus. The XRD analysis confirms the hexagonal close-Packed lattice of the synthesised ZnO nanoparticle. In the UV visible spectrometer (UV – Vis) absorption peak was observed at 314 nm, which is specific for Zinc oxide nanoparticles. Field Emission Scanning Electron Microscope (FESEM) reveals the presence of Zinc oxide nanoparticles in its nanoflakes form. Energy Dispersive Spectrum (EDX) results show strong energy signals of 71.60% and 18.40% for Zinc and Oxygen, respectively. The absorption peak of Zn – O bonding between 404 cm−1 is confirmed by FT- IR spectra. The ZnO nanoparticles degrade 85.29% of Safranin-O dye and 81.57% of Malachite green dye within 90 minutes of time. Antibacterial studies with Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) bacteria have given more than 90% results.

Promising nanocomposites for food packaging based on cellulose – PCL films reinforced by using ZnO nanoparticles in an ionic liquid

The fact that most composites consist of polluting synthetic materials has prompted a search for biodegradable replacements based on cellulose fibers and polycaprolactone as potential packaging materials. In this work, we developed a green, efficient approach to rendering hydrophobic polycaprolactone (PCL) compatible with hydrophilic cellulose fibers by using an ionic liquid as a nanowelding agent in the presence of zinc oxide nanoparticles (ZnONPs). Transparent biobased nanocomposite films were thus directly obtained by in situ ring-opening polymerization (ROP) of ε-caprolactone (CL) monomers onto the dissolved cellulose matrix by using the ionic liquid 1-ethyl-3-methylimidazolium acetate ([EMIM]Ac). [EMIM]Ac and ZnONPs were efficiently catalyzed ε-caprolactone ROP under mild conditions. Cellulose-grafted PCL nanocomposite films were obtained by adding variable amounts of CL and ZnONPs to the cellulose matrix. The maximum grafting of 40% was achieved by using 5▒wt% ZnONPs and 70% CL. FTIR spectra confirmed the presence of PCL in the nanocomposites. Also, FE-SEM revealed uniform dispersion of ZnONPs and PCL in the regenerated cellulose matrix, and trapping of nanoparticles in nanofibrils after the cellulose matrix was regenerated. X-ray diffraction (XRD) spectra showed a decreased apparent crystallinity and crystallite size. The XRD results also confirmed that the crystal properties of the nanocomposite films and an all-cellulose composite (ACC) were almost identical. The mechanical, barrier and optical properties of the nanocomposite films were significantly better than those of the ACC film by effect of the incorporation of ZnONPs and PCL especially with 5▒wt% ZnONPs and 70% CL). The nanocomposite films exhibited acceptable antioxidant activity and UV-light barrier properties, so they hold promise for used in food packaging. Nanocomposite films are in fact multifunctional materials with the potential for use in cellulose-based food packaging by virtue of their being transparent and bio-based, and possessing very good water vapor and oxygen barrier properties.