Synthesis Of ZnO Nanoparticles Research Articles

Facile green synthesis of zinc oxide nanoparticles: Its photocatalytic and electrochemical sensor for the determination of paracetamol and D-glucose

The nanocrystalline zinc oxide (ZnO) was produced utilizing a bio-combustion process with Aloe vera latex extract (Avle) as the fuel. The XRD method proved the nanocrystalline nature and phase of ZnO. The Kubelka-Monk (K-M) function was used to analyze the DRS-UV-vis spectrum, and the results revealed that ZnO has a band gap of 2.79 ​eV. When utilized to evaluate the photo-degradation capabilities of ZnO, the acid red-88 (AR-88) dye was found to be activated at 500 ​nm. After 120 ​min of exposure to UV radiation, the AR-88 dye's photodegradation rate reduced its hue by up to 75.8%. A carbon paste electrode that had been enhanced with ZnO nanoparticles (NPs) was used to detect paracetamol and D-glucose in a 1 ​M KOH solution. The result of the cyclic voltammetry points to the excellent electrochemical qualities of ZnO NPs. ZnO electrode material was found to have a proton diffusion coefficient of 9.30 ​× ​10−5cm2s−1. ZnO is a decent electrode catalyst for sensing chemicals like paracetamol and glucose, according to its electrochemical behavior.

Green chemistry synthesized zinc oxide nanoparticles in Lepidium sativum L. seed extract and evaluation of their anticancer activity in human colorectal cancer cells

In recent years, extensive assessments were performed on metal oxide nanoparticles (MONs) for numerous biomedical implementations. This study aimed to describe a facile, environment-friendly and, green route for the synthesis of Zinc Oxide nanoparticles (ZnO-NPs) by exerting Lepidium sativum L. seed extract as a capping agent and to evaluate their anticancer activities on important human colorectal cancer cell lines, SW480, HT-29 and Caco-2. Characterization of the green chemistry synthesized ZnO-NPs were carried out using UV–visible (UV–Vis) spectroscopy, X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Field emission scanning electron microscope (FE-SEM) and, energy-dispersive X-ray (EDX) spectroscopy. UV–Visible spectra confirmed the biosynthesis of ZnO-NPs and showed a broad absorption peak at 325–450 nm. Microscopic results revealed the formation of the spherical and hexagonal shaped NPs having average size 36.96 and 44.50 nm. In addition, the XRD data demonstrated the crystalline structure of our green ZnO-NPs. In biological experiments, the outcomes of MTT assay indicated the significant cytotoxic effect of ZnO-NPs against SW480, HT-29 and Caco-2 cancer cells through a dosage reliant mechanism. Moreover, the real-time PCR data revealed the potent capability of ZnO-NPs in inducing apoptosis throughout colon cancer cells through the down-regulation of Bcl-2 gene expression and up-regulation of Bax and p53 genes. Overall, these results suggested the applicability of green fabricated ZnO-NPs from the extract of Lepidium sativum L. as a novel and hopeful therapeutic agent for colorectal cancer treatment.

Eco-friendly phytofabrication of Ficus Benjamina L. based ZnO-doped g-C3N4 nanocomposites for remarkable photocatalysis and antibacterial applications

The research reported here emphasizes the phytoextract route synthesized ZnO-doped g-C3N4 (GCN) for its photocatalytic activity, which helps to ensure a sustained & healthy environment. The leaf extract solution of Ficus Benjamina L. was used for the synthesis of ZnO nanoparticles, and GCN was prepared via urea using a thermal polymerization process. The flower extract functions as both stabilizers and capping agents during the process of synthesis of ZnO nanoparticles. The synthesized nanocomposites were then calcined at 400 °C and were further characterized with spectroscopy (UV–Vis), diffracted pattern (XRD), and infrared spectroscopy (FTIR). Further, the photocatalytic activity of auramine orange (AO) and methylene blue (MB) dye from phytoextract route synthesized pure ZnO NPs, GCN-Pure, and composites with varied millimolar concentrations of ZnO nanoparticles with GCN of the constant amount was checked. After the complete analysis, it was observed that the series that was prepared of ZnO-GCN nanocomposites showed notable enhancement in the degradation pattern of the methylene blue dye. Apparently, 1.5 mmol (mM) ZnO-GCN presented greater degradation patterns for Auramine orange and Methylene blue dye as compared to other nanocomposites that were synthesized. The observed increased photocatalytic activity has a conceivable explanation. The antibacterial activity studies of the prepared nanocomposites were also performed against the E. coli strain showing an enhanced zone of inhibition towards it.

Green Synthesis of Novel Antimicrobial ZnO Nanorods

Zinc oxide (ZnO) nanoparticles (NPs) are increasingly used in the diagnosis and prevention of various human infections and diseases. The multi-functional nature of these nanoparticles together with characteristics such as low toxicity and biodegradability, allow their use in a slew of products and applications ranging from biomedical, food and supplement industries, therapeutics and biosensors. ZnO exhibits biomimetic properties enabling biomedical applications, including use as alternatives to pre-existing antibiotics. This study discusses a simple, cost-effective and environmentally sustainable technique for the synthesis of crystalline ZnO nanorods from egg-white or albumin. Single phase nature of the of the engineered nanocrystals was determined using X-ray diffraction (XRD) and selected area electron diffraction (SAED) technique. The morphology of the ZnO nanorods was studied using transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM). The diameter of synthesized ZnO nanorods was determined to be in the range of 20–30 nm. The crystal structure of wurtzite ZnO was discovered by the use of Raman, FTIR, while the surface area (12.8 m2/g) was analyzed by using Brunauer-Emmett-Teller (BET) surface area study. Both gram-positive and gram-negative bacterial strains were used to test the ZnO nanorods’ antibacterial abilities without the need of artificial UV activation. Findings showed that different disease-causing bacteria present in community and hospital settings respond differently to ZnO nanorods’ antibacterial activity. When the concentration of nanorods powder increased, the ratio of bacterial survival dropped, showing an increase in antibacterial activity. The gram-negative strain Pseudomonas aeruginosa was shown to have the maximum antibacterial activity of the ZnO nanorods as compared to other gram-negative and positive bacteria. Eco-friendly and green synthesis of ZnO NPs produce vital multifunctional nanomaterials which possess promising antibacterial properties with more extensive studies may develop drugs for multidrug resistance bacteria.

Surface Characterization of Zinc Oxide Nanoparticles Synthesized via Chemical Route

Introduction: Zinc oxide nanoparticles belong to the new age of nanomaterials; they are being used tremendously for the advancements of biomedicine and modern therapeutic interventions. Purpose: The current antimicrobial treatment methods fail on various levels. Thus, the recent study is dedicated to synthesizing stable zinc oxide nanoparticles. Therefore, the application of zinc oxide nanoparticles as an alternative treatment option is explored. Methods: In the current research, fabrication of zinc oxide nanoparticles is carried out via the wet chemical method. To further confirm the purity and stability of the synthesized material, characterization was performed via zeta potential analysis, thermogravimetric analysis, differential scanning calorimetry, transmission electron microscopy and scanning electron microscopy. Result: SEM and TEM revealed the spherical structure of zinc oxide nanoparticles, also having slight agglomeration at a few points. The thermal stability was tested via thermogravimetric analysis and differential Scanning Calorimetry depicting the strength of the nanomaterial at a very high temperature. Elemental composition was evaluated using Energy Dispersive X-ray Spectroscopy showing 96.01% zinc and 3.99% oxygen, demonstrating the purity of the synthesized zinc oxide nanoparticles. It confirms that no other elements are present apart from zinc and oxygen. Conclusion: Zinc oxide nanoparticles were synthesized via a wet chemical method using zinc nitrate and sodium hydroxide. This fabrication procedure is reliable, cheap, and yields the most stable byproducts. Characterization was carried out via several analytical techniques to check the authenticity of the synthesized nanomaterial, thus revealing that the obtained ZnO nanoparticles could be used in medical interventions as a safe option.

Green Synthesis of Zinc Oxide-Nanoparticles from Ziziphus Spina-Christi Leaves Extract: Characterization and Their Protective Effects Against Liver Disturbances in Adenine-Exposed Male Rats

Zinc oxide nanoparticles (ZnO-NPs) have a significant feature due to their uses in various fields including medicine, biosensors, food additives, and electronic materials. This study aimed to the green synthesis of ZnO-NPs using aqueous extract of Ziziphus-spina christi leaves (Sider) and evaluates its protective roles against liver disorders after adenine-exposed male rats. Thirty-six male rats (3 months in age and weighing 200 ± 5 g) were randomly divided into 6 equal groups as following: Control adenine, Ziziphus-spina christi, ZnO-NPs, adenine + Ziziphus-spina christi and adenine + ZnO-NPs for 30 days. At the end of 30 days, the activity of (alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), superoxide dismutase (SOD) and concentrations of reduced glutathione (GSH) and nitric oxide (NO) were determined, as well as the liver histopathological alterations were investigated. Moreover, the body weight of all rats was measured over a week. The synthesized ZnO-NPs was characterized using several techniques. UV-Visible analysis showed a specific absorption peak at 362 nm. In Fourier Transform Infrared spectroscopy (FT-IR) absorption bands of Zn-O stretching bonding showed between 400 and 500 cm−1. Their crystallinity, hexagonal shape, size, and the specific surface area for the dry ZnO-NPs were also determined using the techniques of X-ray diffraction (XRD) and scanning electron microscopy (SEM) respectively. Results showed significant decreases in ALT, AST and ALP in both groups adenine + Ziziphus-spina christi leaves extract and adenine + ZnO-NPs in comparison to the adenine group (p < 0.05), as well as significant increases in body weight. Significant decrease was also demonstrated in NO level associated with an increase in SOD, and GSH. Based on these results, it can be said that ZnO-NPs and Ziziphus-spina christi leaves effectively protect against adenine-induced liver disorders, these were confirmed by improvements marked in histological changes of liver tissue of rats. GRAPHICAL ABSTRACT

Synergistic Anticandidal Effectiveness of Greenly Synthesized Zinc Oxide Nanoparticles with Antifungal Agents against Nosocomial Candidal Pathogens.

The high prevalence of fungal resistance to antifungal drugs necessitates finding new antifungal combinations to boost the antifungal bioactivity of these agents. Hence, the aim of the present investigation was to greenly synthesize zinc oxide nanoparticles (ZnO-NPs) using an aqueous leaf extract of Salvia officinalis and investigate their antifungal activity and synergistic efficiency with common antifungal agents. The biofabricated ZnO-NPs were characterized to detect their physicochemical properties. A disk diffusion assay was employed to investigate the antifungal effectiveness of the greenly synthesized ZnO-NPs and evaluate their synergistic patterns with common antifungal agents. The Candida tropicalis strain was detected to be the most susceptible strain to ZnO-NPs at both tested concentrations of 50 and 100 µg/disk, demonstrating relative suppressive zones of 19.68 ± 0.32 and 23.17 ± 0.45 mm, respectively. The minimum inhibitory concentration (MIC) of ZnO-NPs against the C. tropicalis strain was 40 µg/mL, whereas the minimum fungicidal concentration (MFC) was found to be 80 µg/mL. The highest synergistic efficiency of the biogenic ZnO-NPs with terbinafine antifungal agent was detected against the C. glabrata strain, whereas the highest synergistic efficiency was detected with fluconazole against the C. albicans strain, demonstrating relative increases in fold of inhibition area (IFA) values of 6.82 and 1.63, respectively. Moreover, potential synergistic efficiency was detected with the nystatin antifungal agent against the C. tropicalis strain with a relative IFA value of 1.06. The scanning electron microscopy (SEM) analysis affirmed the morphological deformations of candidal cells treated with the biosynthesized ZnO-NPs as the formation of abnormal infoldings of the cell wall and membranes and also the formation of pores in the cell wall and membranes, which might lead to the leakage of intracellular constituents. In conclusion, the potential synergistic efficiency of the biogenic ZnO-NPs with terbinafine, nystatin, and fluconazole against the tested candidal strains highlights the potential application of these combinations in formulating novel antifungal agents of high antimicrobial efficiency. The biogenic ZnO nanoparticles and antifungal drugs exhibit powerful synergistic efficiency, which highlights their prospective use in the formulation of efficient antimicrobial medications, including mouthwash, ointments, lotions, and creams for effective candidiasis treatment.

Eco-friendly Synthesis Of Zinc Oxide Nanoparticles by Garcinia cambogia and Evaluation of Their Obesity and Antimicrobial Activities

Eco-friendly Synthesis Of Zinc Oxide Nanoparticles by Garcinia cambogia and Evaluation of Their Obesity and Antimicrobial Activities

Synthesis, characterization, and anticarcinogenic potent of green-synthesized zinc oxide nanoparticles via Citrus aurantium aqueous peel extract

Synthesis of nanoparticles with a green approach using plants has attracted great attention from scientific communities because of its characteristics, such as environmentally friendly and time-efficient. In this study, green synthesis of zinc oxide nanoparticles was performed by Citrus aurantium aqueous peel extract. UV–VIS, FTIR, zeta potential, SEM, and EDX were used in characterization studies. In the UV–Vis spectrum, a heightening of the absorbance was monitored in the range of 260–390 nm specific to ZnO. The mean particle size of zinc oxide NPs (ZnONPs) was characterized as 632 ± 41 nm with low polydispersity (0.174 ± 0.055). As a result of EDX analysis, the presence of Zn in the scanned area was determined as 2.32%. The cytotoxic behaviors of ZnONPs on human breast cancer cells (MDA-MB-231) were carried out by MTT method. It was discovered that after ZnONPs application, cell migration decreased and apoptotic cell rate increased with Hoescht/PI staining in MDA-MB-231 cells.

Synthesis of Zinc Oxide Nanoparticles Using Stem Extract of <i>Citrullus colocynthis</i>, Characterization and Evaluation of its Antibacterial Activity

In the current investigation, an attempt is made to synthesize and characterize the Citrullus colocynthis stem extract loaded Zinc Oxide Nano Particles (ZnONP-Cc) and to evaluate the cytotoxicity and antimicrobial activities of the same. The synthesis of ZnONP-Cc was carried out and the characterization in terms of UV-Spectrum, Fourier Transform Infra-Red (FT-IR) spectrum, Transmission Electron Microscope (TEM), X-Ray Diffraction (XRD) and Scanning Electron Microscope (SEM) analysis were done. The antimicrobial and cytotoxic activities of the ZnONP-Cc were evaluated using the established protocol. In the UV-Spectrum significant SPR peak was observed at 350 nm and FT-IR spectrum exhibited several biomolecules with their chemical entities. Through XRD method, the zinc oxide nanoparticles Face-Centered Cubic (FCC) structure was confirmed. The SEM and TEM confirm the synthesized nanoparticles were round and oval shape with size ranging from 10 - 20 nm. The ZnONP-Cc possess significant antimicrobial activity against wound pathogens and it was found to be non-toxic to the Brine shrimp nauplii. In conclusion, the synthesized ZnONP-Cc can be exploited in nanomedicine since it has antimicrobial activity without any toxicity.

Beta vulgaris extract assisted green synthesis of ZnO nanoparticles: antimicrobial and nano priming studies

In this present study, we report the synthesis of surface-modified zinc oxide (ZnO) nanoparticles (NPs) using chemical method (Z) as well as green method using Beta vulgaris extract (BvZ). The band gap energy of BvZ (3.14 eV) was found to be greater than that of Z (3.0 eV) owing to its smaller particle size. The X-ray diffraction patterns reveal the reduction in crystallite size for BvZ when compared to Z. TEM and SEM images show the agglomeration of particles for BvZ and spherical morphology for Z. The XPS spectra of the BvZ NPs were studied to confirm the oxidation state of Zn ions. Antimicrobial activities of BvZ and Z were tested against bacterial strains such as Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus cereus and fungal strains viz., Candida tropicalis, and Aspergillus niger. The seed germination property of BvZ for chickpea seeds was also studied.

Effect of green synthesized zinc oxide nanoadditives and rice bran oil biodiesel blend on performance and combustion characteristics of a variable compression ratio diesel engine: an experimental study

AbstractThe aim of this research was to investigate experimentally the performance and combustion characteristics of a four‐stroke, single‐cylinder, water‐cooled variable compression ratio diesel engine using rice bran oil biodiesel blends with zinc oxide nanoparticles. Rice bran oil biodiesel was prepared using a transesterification reaction with a 6:1 methanol‐oil molar ratio and 1% w/w potassium hydroxide as catalyst. Zinc oxide nanoparticles were synthesized using a green method incorporating Psidium guajava leaf extract as a capping agent to reduce precursor use and to reduce the toxicity of the nanomaterial. The synthesized zinc oxide nanoparticles were characterized by using X‐ray diffraction and Fourier‐transform infrared spectroscopy to confirm the formation of highly crystalline pure zinc oxide nanoparticles with a hexagonal wurtzite crystal structure with an average diameter of 20.963 nm. Rice bran‐oil biodiesel‐diesel blend was prepared by volumetrically mixing 20% biodiesel and 80% mineral diesel and was considered as a base fuel for comparison. Zinc oxide nanoparticles were diffused in the base fuel at dosage levels of 25, 50, and 75 ppm, with the aid of ultrasonication. Measurement of the major physicochemical properties of test fuels showed an increase in the cetane number and calorific value and a reduction in viscosity with an increase in the zinc oxide concentration. The overall properties of all the test fuels were found to be similar in comparison with commercial diesel. An experimental engine test was carried out under different loading conditions with a constant speed of 1500 RPM and two different compression ratios – that is, 17.5:1 and 15:1. Among all the test fuels at both compression ratios, engine performance and combustion properties improved with an increase in the zinc oxide concentration. Test fuel with 75 ppm of zinc oxide additive at 17.5 compression ratio resulted in an overall improvement at full load: brake thermal efficiency increased by 2.45%, brake specific fuel consumption reduced by 5.45%, cylinder peak pressure increased by 3.27% and net heat release increased by 10.32% in comparison with base fuel.

Controlled synthesis of zinc oxide nanoparticles through flame spray pyrolysis and evaluation of their anticancer effects against gastric cancer cell

Although zinc oxide nanoparticles (ZnO NPs) have demonstrated promising anticancer activity, their therapeutic performances are frequently influenced by the synthesis routes and associated distinct physicochemical characteristics. Herein, ZnO NPs were synthesized through a cost-effective flame spray pyrolysis-assisted approach and their selective anticancer effects and underlying intrinsic apoptosis signaling pathway in human gastric carcinoma cell line (AGS) were examined. Transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and dynamic light scattering (DLS) investigations were used to characterize the synthesized ZnO NPs. Afterwards, AGS and normal fibroblast cells (L-929) were treated with various concentrations of ZnO NPs, and cell proliferation was examined by the MTT assay to determine the IC50 concentration of NPs. Furthermore, the quantification of ROS and apoptosis was done by fluorometer and flow cytometry assays. Additionally, superoxide dismutase (SOD) and catalase (CAT) activity assays were performed to evaluate the oxidative stress-induced cytotoxicity mediated by ZnO NPs against AGS cells. Moreover, caspase-3/-8/-9 activity and mitochondrial membrane potential (MMP) assays were done. Finally, the expression levels of p53, Bax, Bcl-2, caspase-9/-8/-3, and cytochrome c were assessed by quantitative real time PCR and western blot analyses to explore the probable mitochondrial apoptosis signaling pathway induced by ZnO NPs in AGS cells. The results showed that ZnO NPs with an absorption maximum at 350 nm, an average size of 70 nm, a hydrodynamic radius of 92.89 nm, and a zeta potential of −43.13 mV potentially and selectively inhibited the proliferation of AGS cells in comparison with L-929 cells through a remarkable increase in the production of ROS, induction of apoptosis, reduction of SOD and CAT activity, activation of caspase-9/-3, and MMP disruption. Moreover, ZnO NPs triggered up-regulation of p53, Bax, caspase-9/-3, cytochrome c and down-regulation of Bcl-2 at mRNA and protein levels. This study suggests that synthesized ZnO NPs through flame spray pyrolysis can induce selective anticancer effects against gastric cancer cells via intrinsic apoptosis signaling pathway.

A green synthetic approach for the morphological control of ZnO-Ag using β-cyclodextrin and honey for photocatalytic degradation of bromophenol blue

Green synthetic approaches aid control of physicochemical properties of nanoparticles and decrease the environmental footprint of the nanoparticles. Herein, novel synthesis of ZnO nanoparticles (NPs) using natural surfactants and sequential investigation of their optical, physicochemical and photocatalytic properties are conducted. This work utilizes β-cyclodextrin (βCD) and honey as surfactants during the production process. It is demonstrated that these natural surfactants have the ability to control size, shape, crystalline phase growth and dispersion of NPs (denoted as ZnO-C and ZnO-H). Subsequent coupling of ZnO NPs with Ag to form the binary nanostructures (ZnO-xAg, ZnO-C-xAg and ZnO-H-xAg) further assists controlling their physicochemical properties. With a variation of Ag NPs loading, the 3 wt% Ag loaded nanophotocatalysts were more efficient and their associated properties were revealed by various characterization techniques. Nanoparticles of different shapes were fabricated with a surface area of up to 10 m2.g−1 and crystalline sizes of 9.38 nm. Photoluminescent spectroscopy indicated that Ag nanoparticles enhanced the life span of electron-hole pairs. Thus, photodegradation of bromophenol blue (BPB) indicated enhanced NPs photoactivity upon modification with CD, honey, and Ag NPs. BPB photodegradation was > 99.84% using ZnO-H-3Ag with reaction rates of k0app=518.8×10−2min−1 and up to 75% total organic carbon was removed by ZnO-H-3Ag at a rate of 8.19×10−3min−1.

Characterization and photocatalytic activity of ZnO nanoparticles by green synthesis method

In this work, zinc oxide nanoparticles have been synthesized by green synthesis technique using sodium hydroxide and zinc nitrate, with and without calcination. In this research, Myrtus communis extract was used along with three different alkaline molar ratios (0.5 M, 1 M, and 2 M) to successfully synthesize ZnO nanoparticles (NPs) from the same precursor. In the calcined samples, this process was carried out at 800 °C. X-ray diffraction, scanning electron microscopy, and diffuse reflectance spectra were used to explore the structural, morphological, and optical features of ZnO nanoparticles. The XRD peaks confirm the successfully synthesized hexagonal wurtzite zinc oxide and are in full conformity with the published data of the JCPDS: 36–145. With high absorption peaks at about 370 nm wavelength, UV-Vis spectroscopy further supported the ZnO NPs' strong optical properties. Morphology and topography were discovered by SEM analysis and displayed the evolution of ZnO nanowires around 10 µm length with calcination. No nanowire formation was observed in the uncalcined samples. The results demonstrated that the degradation efficiency of ZnO nanoparticles is dependent primarily on the UV exposure time and morpholgy. When ZnO with 1 M NaOH calcined at 800 °C is used, the maximum MB degradation of about 99% is achieved. Methyl blue photodegradation follows the first-order Langmuir–Hinshelwood kinetic model.

Synthesis of zinc oxide nanoparticles using methanol propolis extract (Pro-ZnO NPs) as antidiabetic and antioxidant.

In recent times, the overall health of individuals has been declining due to unhealthy lifestyles, leading to various diseases, including diabetes. To address this issue, antidiabetic and antioxidant agents are required to back-up human well-being. Zinc oxide (ZnO) is one such substance known for its antidiabetic and antioxidant effects. To enhance its capability and effectiveness, propolis was utilized to synthesize zinc oxide nanoparticles (Pro-ZnO NPs). The objective of this study was to synthesize Pro-ZnO NPs and assess their performance by conducting inhibition assays against α-amylase and α-glucosidase enzymes, as well as a 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay. The results showed that Pro-ZnO NPs were formed in a hexagonal wurtzite structure, with particle sizes ranging from 30 to 50 nm and an absorption band observed at 341 nm. The stability, chemical properties, and crystallography of Pro-ZnO NPs were also thoroughly examined using appropriate methods. The Pro-ZnO NPs demonstrated significant inhibitory effects against α-amylase and α-glucosidase enzymes, with inhibition rates reaching 69.52% and 73.78%, respectively, whereas the antioxidant activity was as high as 70.76%. Consequently, with their high inhibition rates, the Pro-ZnO NPs demonstrate the potential to be employed as a natural agent for combating diabetes and promoting antioxidant effects.

Morphology-controlled atmospheric pressure plasma synthesis of zinc oxide nanoparticles for piezoelectric sensors

Zinc oxide nanoparticles, especially those with a high aspect ratio (i. e., nanorods and nanowires), are of great interest for many applications as they are piezoelectric, photocatalytic and antimicrobial. In the present study, a plasma flight-thru synthesis method was developed that allows controlling the particle size and shape of the zinc oxide nanoparticles. In a direct current thermal plasma reactor operated at atmospheric pressure, zinc powder injected into the plasma jet was molten, vaporized and oxidized, which allowed growing zinc oxide nanoparticles. The particle spectrum ranged from small nanospheres to nanorods, nanowires and multipodic nanoparticles such as tetrapods. The influence of the oxygen rate and the plasma power (correlated to the discharge current) on the particle morphology was studied, and the feasibility of the nanowire-like particles as piezoelectric sensor material was investigated. Piezoelectric test sensors, equipped with the plasma-synthesized zinc oxide nanowires, successfully responded to mechanical stimulation after poling.

Induction of tomato plant biochemical immune responses by the synthesized zinc oxide nanoparticles against wilt-induced Fusarium oxysporum.

Thecurrent study used zinc oxide nanoparticles (ZnO-NPs) to protect the tomato plant against Fusarium wilt. Gamma rays were used to synthesize ZnO-NPs, and the designed ZnO-NPs were characterized using high-resolution transmission electron microscopy (HRTEM), scanning electron microscope (SEM), dynamic light scattering (DLS), energy-dispersive X-ray spectroscopy (EDX), and ultraviolet-visible (UV-Vis.) spectroscopy. We found that the 20 kGy dose is the most effective for ZnO-NPs synthesis, with the highest O.D. = 1.65 (diluted 3 times) at 400 nm. The scale of ZnO-NPs ranged from 10.45 to 75.25 nm with an average diameter of 40.20 nm. The results showed that the designed ZnO-NPs showed promising activity as a potent inducer of plant physiological immunity against Fusarium wilt disease. Likewise, ZnO-NPs significantly reduced the wilt disease symptoms incidence by 28.57% and high protection by 67.99% against F. oxysporum. Additionally, infected tomato plants treated with ZnO-NPs show improved shoot length (44.71%), root length (40.0%), number of leaves (60.0 %), chlorophyll a (36.93%), chlorophyll b (16.46%), and carotenoids (21.87%) versus infected plants. Notably, in the treatment of tomato seedlings, the beneficial effects of ZnO-NPs extended to increase not only in osmolyte contents but also total phenol contents in comparison with control plants. In conclusion, the designed ZnO-NPs can control Fusarium wilt disease and improve and develop biochemical compounds responsible for defense against fusarial infection.

Green Synthesis of Zinc Oxide Nanoparticles Using Cymbopogon citratus Extract and Its Antibacterial Activity.

Excessive use of antimicrobial medications including antibiotics has led to the emerging menace of antimicrobial resistance, which, as per the World Health Organization (WHO), is among the top ten public health threats facing humanity, globally. This necessitates that innovative technologies be sought that can aid in the elimination of pathogens and hamper the spread of infections. Zinc oxide (ZnO) has multifunctionality owing to its extraordinary physico-chemical properties and functionality in a range of applications. In this research, ZnO nanoparticles (NPs) were synthesized from zinc nitrate hexahydrate, by a green synthesis approach using Cymbopogon citratus extract followed by characterization of the NPs. The obtained X-ray diffraction peaks of ZnO NPs matched with the standard JCPDS card (no. 89-510). The particles had a size of 20-24 nm, a wurtzite structure with a high crystallinity, and hexagonal rod-like shape. UV-Vis spectroscopy revealed absorption peaks between 369 and 374 nm of ZnO NPs synthesized from C. citratus extract confirming the formation of ZnO. Fourier transform infrared confirmed the ZnO NPs as strong absorption bands were observed in the range of 381-403 cm-1 corresponding to Zn-O bond stretching. Negative values of the highest occupied molecular orbital-lowest unoccupied molecular orbital for ZnO NPs indicated the good potential to form a stable ligand-protein complex. Docking results indicated favorable binding interaction between ZnO and DNA gyrase subunit b with a binding energy of -2.93 kcal/mol. ZnO NPs at various concentrations inhibited the growth of Escherichia coli and Staphylococcus aureus. Minimum inhibitory concentration values of ZnO NPs against E. coli and S. aureus were found to be 92.07 ± 0.13 and 88.13 ± 0.35 μg/mL, respectively, at a concentration of 2 mg/mL. AO/EB staining and fluorescence microscopy revealed the ability of ZnO NPs to kill E. coli and S. aureus cells. Through the findings of this study, it has been shown that C. citratus extract can be used in a green synthesis approach to generate ZnO NPs, which can be employed as alternatives to antibiotics and a tool to eliminate drug-resistant microbes in the future.

Green synthesis of Cu-Mn co-incorporated ZnO nanoparticles for antibacterial and photocatalytic applications.

The synergistic effect of bimetallic co-incorporated metal oxides have gained enormous attention due to their unique optoelectronic properties. Herein, we present the green synthesis of ZnO, Cu-incorporated ZnO, Mn-incorporated ZnO, and Cu-Mnco-incorporated nanoparticles (ZnO NPs, CuZnO NPs, MnZnO NPs, MnCuZnO NPs) for antimicrobial and photocatalytic reduction applications using corn silk extract and industrial metal wastes. The as-synthesized NPs were characterized by using UV-visible absorption spectroscopy (UV-Vis), photoluminescence (PL) spectroscopy, Fourier-transformed infrared spectroscopy (FT-IR), powdered x-ray diffraction (XRD), and scanning electron microscopy (SEM). CuZnO, MnZnO, and MnCuZnO NPs efficiently inhibited bacterial culture growth. The photocatalytic reduction activity of as-synthesized NPs against the different concentrations of 4-nitrophenol (4-NP) in water was also investigated. CuZnO and MnCuZnO nanoparticles were to be efficient photocatalysts for reducing 4-NP into 4-aminophenol (4-AP). RESEARCH HIGHLIGHTS: Green synthesis of nanomaterials by agricultural and industrial wastes Cu and Mn co-incorporated ZnO NPs have shown good photocatalysis and antimicrobial activities Green approach for waste conversion to value-added products.