Different Concentrations Of ZnO Nanoparticles Research Articles

Reinforcement of the antimicrobial activity and biofilm inhibition of novel chitosan-based hydrogels utilizing zinc oxide nanoparticles

Two novel chemically cross-linked chitosan hydrogels were successfully prepared via insertion of oxalyl dihydrazide moieties between chitosan Schiff's base chains (OCsSB) and between chitosan chains (OCs). For more modification, two different concentrations of ZnO nanoparticles (ZnONPs) were loaded into OCs to obtain OCs/ZnONPs-1 % and OCs/ZnONPs-3 % composites. The prepared samples were recognized using elemental analyses, FTIR, XRD, SEM, EDS and TEM. Their inhibitory action against microbes and biofilms were classified as: OCs/ZnONPs-3 % > OCs/ZnONPs-1 % > OCs > OCsSB > chitosan. OCs has inhibition activity similar to Vancomycin of minimum inhibitory concentration (MIC) value of 3.9 μg/mL against P. aeruginosa. OCs exhibited minimum biofilm inhibitory concentration (MBIC) values (from 31.25 to 62.5 μg/mL) less than that of OCsSB (from 62.5 to 250 μg/mL) which lower than that of chitosan (from 500 to 1000 μg/mL) against S. epidermidis, P. aeruginosa and C. albicans. OCs/ZnNPs-3 % showed MIC value (that caused 100 % inhibition of Clostridioides difficile, C. difficile) of 0.48 μg/mL much lower than Vancomycin (1.95 μg/mL). Both OCs and OCs/ZnONPs-3 % composite were safe on normal human cells. Thus, inclusion of oxalyl dihydrazide and ZnONPs into chitosan greatly reinforced its antimicrobial activity. This is a good strategy to accomplish adequate systems for competing traditional antibiotics.

Saudi Cotton Fabrics Treated with Chitosan and Different Concentrations of ZnO Nanoparticles: Preparation, Characterization, and Demonstration

Saudi Cotton Fabrics Treated with Chitosan and Different Concentrations of ZnO Nanoparticles: Preparation, Characterization, and Demonstration

Effect of zinc nanoparticles on the growth and biofortification capability of mungbean (Vigna radiata) seedlings.

The online version contains supplementary material available at 10.1007/s11756-022-01269-3.

Experimental analysis of the effect of zinc oxide nano additive diesel-ethanol blend on the performance and emission characteristics of a variable compression ratio diesel engine at various compression ratios

The two significant challenges facing the world are growing pollution issues and fossil fuel depletion. Emissions emanating and consumption of fossil fuels in diesel engines are reduced by modifying engine operating parameters and by developing more efficient alternative fuels. In view of this, the current work evaluates the effect of ZnO nanoparticles mixed with diesel-ethanol blend on the working characteristics of diesel engine at different CR’s and loads. The test fuels selected for the experimental work are pure diesel, DE10, DE10ZnO50 and DE10ZnO100, and the compression ratios are 16.5, 17.5 and 18.5. Using ultrasonic agitation, ZnO nanoparticles were incorporated in fuel blends in the presence of 2% surfactant span80. All fuel blends were tested for their physicochemical properties, and it was noted that the fuel properties improved when ZnO nanoparticles were added to the test blends. The results showed that at CR 18.5, the DE10ZnO100 fuel blend shown maximum improvement in engine working characteristics as compared to other blends. In comparison to diesel at CR 18.5 for DE10ZnO100 blend, BTE enhanced by 5.73% and BSFC was reduced by 8.31%. CO, NOx and UHC emissions are reduced by 21.96%, 6.41% and 12.07%, whereas CO2 emissions have increased by 7.44%, respectively. HIGHLIGHTS Different concentration of ZnO nanoparticles incorporated diesel-ethanol blend is prepared. The effect of ZnO nanoparticles diesel-ethanol blend at various compression ratios of diesel engine was investigated Optimal results are noted for the DE10ZnO100 blend at compression ratio 18.5. Improvements in BTE and BSFC is 5.73% and 8.31% as compared to diesel at CR 18.5 for DE10ZnO100 blend. CO, UHC and NOx reduced by 21.96%, 12.07% and 6.41%.

Fabrication and evaluation of poly (vinyl alcohol)/gelatin fibrous scaffold containing ZnO nanoparticles for skin tissue engineering applications

Skin engineering offers innovative constructs for the treatment of a wide range of skin diseases. Hybrid scaffolds were fabricated using poly (vinyl alcohol), gelatin and ZnO nanoparticles by electrospinning. Different concentrations of ZnO nanoparticles (0%, 0.5% and 1%) were incorporated into the PVA/gelatin scaffolds and the constructs were characterized by SEM, FTIR, XRD, contact angle, swelling, degradation, and biomechanical tests; the release behavior of nanoparticles from the scaffolds was also evaluated. In cellular studies, human mesenchymal stem cells (hu-MSCs) were extracted from the umbilical cord of a newborn baby and characterized by flow cytometry. Cell-seeded scaffolds were assessed by in vitro biocompatibility, SEM images and live/dead assay. Finally, the antibacterial activity of scaffolds against E. coli and S. aureus strain was determined. Due to the presence of the hydrophilic biopolymer of gelatin in the contact angle test, the scaffolds showed hydrophilic properties. With the addition of nanoparticles, the hydrophilicity, water absorption and degradation rates of scaffolds were somewhat reduced. No difference in tensile modulus was observed between scaffolds. The release rate of nanoparticles from scaffolds increased over time. The immunoprofile evaluation of extracted cells by flow cytometry technique confirmed the mesenchymal nature of the cells. Fluorescent staining showed that most cells were alive and had appropriate shape during six days of cell culture on PVA/gelatin/ZnO1wt% scaffold. All scaffolds had acceptable biocompatibility, but control and PVA/gelatin groups showed a higher cell survival rate. Scaffolds containing nanoparticles had a direct effect on inhibiting bacterial growth in a dose-dependent manner. Our findings suggest that composite scaffolds containing ZnO nanoparticles seeded with hu-MSCs might be suitable for promoting skin healing.

Seed priming with ZNPs reduced expression of salinity tolerance genes in Glycine max L. and improved yield traits

Little has been done to evaluate the molecular role of ZnO nanoparticles (ZNPs) in regulating biochemical processes and plant yield in response to salt-induced stress. In this study, the molecular response of salt-stressed soybean (‘Giza111’) was assessed under different concentrations of ZNPs (25, 50, 100, and 200 mg l-1) by measuring some osmolytes, yield parameters, and Na+ and K+ content. The impact of salinity on the mRNA expression levels of three key salt-tolerance related genes (GmCHX1, GmPAP3, and GmSALT3) using qRT-PCR was also determined. The high level of salinity (250 mM NaCl) led to a significant increase in Na+ content, total soluble proteins, and total soluble carbohydrates and significantly upregulated gene expression of GmCHX1, GmPAP3, and GmSALT3, while reducing K+ content, K+/Na+ ratio and all yield parameters compared to control plants. Soaking soybean seeds in various ZNP concentrations, on the other hand, increased K+ content and K+/Na+ ratio while decreasing Na+ content, total soluble proteins, and total soluble carbohydrates in stressed plants, particularly at 50 mg l-1 ZNPs. Furthermore, GmCHX1, GmPAP3, and GmSALT3 expressions were all downregulated at 50 mg l-1 ZNPs, which ultimately improved soybean yield parameters. Accordingly, these results recommend the application of 50 mg l-1 ZNPs for improving the productivity of soybean cultivated in saline soils.

In situ polymerization of curcumin incorporated polyurethane/zinc oxide nanocomposites as a potential biomaterial

Curcumin incorporated polyurethanes (CPU) are gaining much attention as a biomaterial. However, challenges are still remained due to hydrophobicity and low mechanical strength of CPU. Herein, we synthesized the CPU/ZnO nanocomposites with good mechanical and improved hydrophilic properties via in-situ polymerization. A series of curcumin incorporated polyurethane with different concentrations of ZnO nanoparticles (ZnCPU) are synthesized by using the curcumin, polyethylene glycol (PEG) as the soft segment, hexamethylene diisocyanate (HDI) as the hard segment, and 1,4-butanediol (BDO) as the chain extender. The addition of ZnO nanoparticles (NPs) facilitated the soft domain of PU which is confirmed by DSC analysis. TGA results revealed that the thermal stability of PU is improved by the incorporation of curcumin and ZnO NPs into the backbone of PU. The sample Zn2CPU showed the enhanced storage moduli which is due to the disturbance of hydrogen bonding between the soft and hard segment of PU. The addition of ZnO NPs in the CPU demonstrated interesting results for the mechanical analysis as the breaking strain of sample Zn3CPU (2331%) is higher than the CPU (1758%). It is also observed that the hydrophilicity is increased with the addition of ZnO in ZnCPU. The results of antibacterial activity showed the maximum decline of active bacterial growth (11 ± 1.55%) with the 5% content of ZnO NPs. Generally, these synthesized ZnCPU composites can be employed as an effective biomaterial in the future.

Differential Comprehensive Effects of Food Quality and ZnO Nanoparticles on the Key Traits of Early Life History of Daphnia magna

In aquatic ecosystems, cladocerans, an important part of zooplankton, are often exposed to new pollutant nanoparticles and poor quality food simultaneously. To evaluate the combined effects of poor quality food and nanoparticles on the development and early reproductive performance of cladocerans, we exposed Daphnia magna, a representative cladoceran, to different concentrations of ZnO nanoparticles under the food conditions containing different proportions of non-toxic Microcystis, recorded some key indicators of the early life history, and analyzed the possible differential dose effects. The results showed that non-toxic Microcystis and ZnO nanoparticles significantly delayed the times to maturation and reproduction and also significantly reduced the survival time, the body length at maturation, the number of offspring in the first brood, and the total offspring per female of D. magna. When the food contained non-toxic Microcystis, D. magna did not reach sexual maturity at 0.25 mg L−1 ZnO nanoparticles and did not develop eggs and reproduce offspring at 0.20 mg L−1 ZnO nanoparticles, especially non-toxic Microcystis and ZnO nanoparticles had a significant or nearly significant synergistic effect on the time to maturation, time to first brood, and the total offspring per female of D. magna, whereas for other life history indicators, non-toxic Microcystis and ZnO nanoparticles showed an additive effect, based on comparing the slopes of linear fitting of the relevant indicators with nanoparticle concentration under different food quality conditions. Such findings are helpful to realistically evaluate the comprehensive stress effect on zooplankton under the complex conditions of poor food quality and coexistence of pollutants.

Food abundance mediates the harmful effects of ZnO nanoparticles on development and early reproductive performance of Daphnia magna

Most aquatic ecosystems are at risk of being polluted by new environmental pollutant nanoparticles. As the main food source of zooplankton, the biomass of algae always fluctuates. Cladocerans, an important part of zooplankton, are usually be simultaneously exposed to different abundance of algae and nanoparticles in aquatic environment. To evaluate the combined effects of food abundance and ZnO nanoparticles concentration on the development and early reproductive performance of cladocerans, we exposed Daphnia magna, a common and representative model organism in cladocerans, to the combinations of different abundances of Chlorella pyrenoidosa and different concentrations of ZnO nanoparticles, recorded the key life-history traits, and used multiple models to fit the data. Results showed that high level of ZnO nanoparticles and low abundance Chlorella had an interactively negative effect on the life history of D. magna. When D. magna was exposed to ZnO nanoparticles, some life history traits, such as survival time, body length at maturation, and offspring per female, increased exponentially with the increase of food abundance, and then reached a theoretical maximum value, whereas some other life history traits, such as time to maturation and time to first brood, showed an opposite trend. However, higher Chlorella abundance reduced the negative effect of ZnO nanoparticles on D. magna, but the negative effect could not be eliminated with the increase of food abundance. Below Chlorella 0.30 mg C L−1, food plays a decisive role, while at or above this threshold, ZnO nanoparticles play a decisive role. Therefore, the effect of different ZnO nanoparticles concentrations can be fully reflected only when food is sufficient, and the negative effects of food shortages may mask the toxic effects of ZnO nanoparticles on D. magna. The findings indicated that the effects of food abundance should be considered in evaluating the realistic impact of pollutants on zooplankton.

Comparative in vitro study of the antimicrobial activity of metal-ZnO nanoparticles against several bacterial and fungal pathogens

Nowadays, the use of nanoparticles (NPs) has become useful in the different application fields. The aim of this study was to investigate the in vitro antimicrobial potential of metal-ZnO nanoparticles (ZnO NPs) against several bacterial and fungal strains including; Escherichia coli (ATCC 25922), Bacillus cereus (ATCC 13753), Staphylococcus aureus (ATCC 8095), Pseudomonas aeruginosa (ATCC10662), Candida albicans (ATCC10231) and Aspergillus niger (AUMC3663). Results obtained by X-ray diffraction analysis (XRD) showed that the NPs size was in the range of 35.1- 43.7 nm. Images of the scanning electron microscopy (SEM) demonstrated the rod shape nature of the ZnO NPs, and the semi-spherical shapes of the Zn9.7TM0.3O NPs. The effect of different concentrations of ZnO NPs on the in vitro growth of the bacterial and fungal strains was evaluated using the agar well diffusion assay. Current results showed that Cd-ZnO NP recorded the highest antimicrobial potency; expressing inhibition zones diameter range of 12- 45 mm, while ZnO NPs demonstrated the least activity exhibiting inhibition zones diameter that ranged from 0- 36 mm. Among all the examined ZnO-NPs, treatment of E. coli and Staph. aureus cells with Cd-ZnO proved to be the most effective in causing membrane leakage of reducing sugars, protein and DNA recording; 0.41 µg/ ml and 0.38 µg/ ml; 14.91 µg/ ml and 15.98 µg/ ml; 0.81 µg/ ml and 0.96 µg/ ml, respectively. This study emphasized that ZnO NPs could be used as alternative antimicrobial agents to control the bacterial and fungal pathogens. Manipulation of ZnO NPs is ecofriendly; as it reduces the use of the synthetic pesticides and chemical therapeutic agents, which pollute the environment. In the future, in vivo application of these NPs necessitates the proof that they have no phytotoxicity andor cytotoxicity.

Impacts of ZnO nanoparticles on growth and antioxidant enzymes of the green alga Scenedesmus obliquus

The growing passion for new industrial technology, using innovative materials such as nanoparticles (NPs) which reached water bodies as wastewater, heavily influenced aquatic organisms and consequently the human life. Physiological characteristics of the micro-green alga Scenedesmus obliquus can be used as biomarker to evaluate the effects of the newly invited zinc oxide nanoparticles (ZnO NPs). S. obliquus was exposed to different concentrations of ZnO NPs. The recorded results clarify not only an obvious inhibition in growth but also disturbance in the production of the tested antioxidant enzymes, where both Glutathione reductase (GR) and Glutathione peroxidase gradually increase with ZnO NPs concentration giving its maximum within 100 μg Zn NP.L–1 at the end of the experiment (562 and 0.42 μg.μg–1 respectively). However, in the case of Glutathione (GSH), Glutathione S-transferase (GST) and catalase (CAT) the gradual increase recorded only during the first 24 h, while Superoxide Dismutases (SOD) started to decrease within concentration of 50 μg L–1ZnO NPs. Scanning electron microscope clarifies abnormalities in the cytomorphological characteristics of the treated cells where the cells tended to aggregate in a cluster and take elongated and spindle-shaped and/or wrapping. The various responses to ZnO NPs concentrations reflected, the disposal of ZnO nanoparticles in the environment affecting growth, morphological, and physiological characteristic of the cell.

Role of incorporation of ZnO nanoparticles on corrosion behavior of ceramic coatings developed on AZ31 magnesium alloy by plasma electrolytic oxidation technique

Improvement of corrosion resistance is one of the main goals in developing plasma electrolytic oxidation (PEO) ceramic coatings on AZ31 magnesium alloys. In this study, ceramic coatings were deposited on AZ31 magnesium alloys by PEO technique in electrolytes containing 10 g/l sodium phosphate (Na3PO4) and 1.5 g/l sodium hydroxide (NaOH) at different concentrations of ZnO nanoparticles and current density of 7.1 A/dm2 for 10 min. To investigate the corrosion behavior of the samples, they were placed in Hank's solution, while Tafel polarization and electrochemical impedance spectroscopy (EIS) were used. X-ray diffraction (XRD) together with field emission scanning electron microscopy (FESEM) and energy dispersive spectroscopy (EDS) techniques were employed to investigate the coatings. XRD results showed that the prepared PEO layers mainly consist of ZnO, Mg, and Mg3(PO4)2 phases. Corrosion test results showed that the use of ZnO nanoparticles improved the corrosion resistance of PEO ceramic coatings in Hank's solution. In contrast, the best result was obtained by using the electrolyte containing 6 g/l ZnO nanoparticles with a corrosion current density of 0.08 µA/cm2 and corrosion potential of -1.4615 VAg/AgCl. Also, EIS results showed the corrosion resistance of the mentioned coating as 1.05 × 106 Ω.cm2.

Assessment Various Concentrations of ZnO-Nanoparticles on Micropropagation for Chenopodium quinoa Willd. Plant

Assessment influences various concentrations of ZnO-Nanoparticles (ZnO-NPs) on Chenopodium quinoa Willd. Micro-propagation by cotyledonary nodes explants was achieved. We used different concentrations of ZnO-NPs (0.2, 2, 10, 20 mg/l) and used the medium free from ZnO-NPs as control. The results indicated that the presence ZnO-NPs in medium was good effect on germination rate of quinoa seeds at 2 mg/l concentration, and we noticed a density in roots hair and number or length roots of seedling. In addition, the highest responding of explant to ZnO-NPs 93.33, 80.8% were in MS that supplemented 0.0, 2.0 mg/l respectively. Maximum numbers of roots 4.0 were also observed in MS containing 0.0, 2.0 mg/l. Although, there was positive clearly effect on number leaves of shoots, but there was a sudden decline (from 8.43 to 1.0) occurred by increasing ZnO-NPs concentrations from 2.0 to 20.0 mg/L. However, the ZnO-NPs do not effect on length of shoots, where the lengthiest shoot occurred in MS without ZnO-NPs. Regarding rooting shoots, there was significant effect of ZnO-NPs on both percentage of root and root number, where percentage of root reached to 100% in 10.0 mg/l concentration and roots number was 4.80 roots in the same concentration.

Morphological effect of ZnO nanostructures on desalination performance and antibacterial activity of thin-film nanocomposite (TFN) membrane

This study highlights the effect of shape-controlled nanostructures on the desalination efficiency of thin-film nanocomposite (TFN) membranes. ZnO nanostructures such as nanoflowers (F-ZnO), nanorods (R-ZnO), and spherical nanoparticles (S-ZnO) were synthesised using hydrothermal and sol-gel processes. The chemical and structural characteristics of nanoparticles and the TFN membranes were analysed using X-ray diffraction, Fourier transform infrared spectroscopy, transmission and scanning electron microscopy, contact angle measurement, and atomic force microscopy. The desalination performance of TFN membranes was investigated after the incorporation of different concentrations of ZnO nanoparticles (S-ZnO, F-ZnO, and R-ZnO) ranging from 0– to 0.03 wt%. Irrespective of the ZnO morphology, the TFN membrane showed improved hydrophilicity with an increase in ZnO loading. The S-ZnO/0.02 TFN membrane exhibited the highest permeate flux (23.85 L/m2·h) and relatively better NaCl rejection (97%), which can be attributed to higher surface area and smaller size of S-ZnO compared to F-ZnO and R-ZnO nanostructures. Furthermore, antifouling study (with DH5-alpha strain, Escherichia coli) for S-ZnO/0.02 TFN membrane revealed a reduction in viable cells to 70% after 180 min of contact compared to the thin-film composite (TFC) membrane. The S-ZnO/0.02 TFN membrane displayed enhanced operational stability, which confirms the stable embedment of S-ZnO nanoparticles in the selective polyamide layer.

Role of Zinc Oxide Nanoparticles in Ameliorating Salt Tolerance in Soybean

AS LONG as we know, little attention has been given to evaluating roles of ZnO nanoparticles (ZnONPs) in plants grown under salinity stress. In the present study, biochemical and molecular responses of salt-stressed soybean cv. Giza111 under different ZnONPs were assessed. Treatment with a high NaCl concentration (250mM) alone caused a significant reduction (65%) in germination percentage as well as a significant decrease in all measured growth parameters (root length, shoot height, fresh and dry weight of roots and shoots) and photosynthetic performance (Fv/Fm) compared to control plants. In contrast, malondialdehyde (MDA) & proline contents, and activities of antioxidant enzymes (catalase CAT, peroxidase POX and superoxide dismutase SOD) were highly increased. In contrast, presoaking of soybean seeds with different concentrations of ZnONPs (25, 50, 100, 200mg/L) stimulated the growth of stressed plants which was exhibited by improved growth parameters and photosynthetic performance as well as lower levels of proline and MDA in stressed plants particularly at ZnONPs concentration of 50 mg/L compared to controls. Moreover, isozyme analysis of CAT, POX and SOD showed variable pattern of alleles at 50mg/L ZnONPs. Accordingly, these results recommend application of 50mg/L ZnONPs for improving the productivity of soybean cultivated in saline soils.

Enhanced Photocatalytic and Antibacterial Performance of ZnO Nanoparticles Prepared by an Efficient Thermolysis Method

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

Estimate of the Antifungal Activity and Phytotoxicity of ZnO Nanoparticles on Magnaporthe oryzae and Rice Cultivar Sakha 101 using Morphological, Biochemical and Molecular Markers

Riceblast caused by Magnaporthe oryzae is the major biotic stress influences rice yield. The current investigation aimed to estimate the antifungal activity and phytotoxicity effect of different concentrations of ZnO nanoparticles (0.0, 10, 25, 50, 100 and 200 mg/L) on M. oryzae and rice cultivar Sakha101 using morphological, biochemical and molecular markers. Five ISSR markers and seven RAPD primers were utilized to estimate the potentiality effects of ZnO nanoparticles (NPs). The effect of different rates and applications of ZnO NPs used to control rice blast disease and improve grain yield were estimated in the field during 2017 and 2018 growing seasons. The results showed that, in vitro antifungal assay of ZnO NPs showed a significant decrease in colony formation in comparison to control. Foliar application of ZnO NPs at 25 mg/L was the most effective treatments for mitigation rice blast at five days before inoculation. While under field conditions, foliar spray with 25 mg/L at nursery increased the grain yield to 4.366 ton/fed in season 2017 and to 4.625 ton/fed in 2018. Foliar spray with ZnO NPs of rice offer a practical and useful approach to improve rice grain yield and reduce leaf blast disease when applied at optimal concentrations. ZnO NPs at lower concentrations (10 and 25 mg/L) enhanced seed germination and improved seedling growth, while the higher concentrations (100 and 200 mg/L) resulted in phytotoxicity. ZnO NPs treatments altered the expression patterns of seeds storage protein; induced newly synthesized isoforms and disappearance of existing ones. The obtained results using molecular markers confirmed that the lower concentrations of ZnO-NPs (10 and 25 mg/L) are considered as a good enhancement agent, as in case of rice cultivar Sakha101, using UBC 825 primer with 306 bp at concentration of 25 mg/L and OPA-9 primer with 948 bp at concentration of 10 mg/L. For M. oryzae the same trend of effects was appeared in case of UBC 880 primer with 994 bp at concentration of 25 mg/L and OPO-10 primer with 268 bp at concentration of 10 mg/L. In general, these results suggested that lower concentrations of ZnO NPs could be applied as an effective nano fertilizer for sustainable agriculture and food safety, and moreover, utilized as antifungal agent for rice blast disease.

Modulation of callus growth and secondary metabolites in different Thymus species and Zataria multiflora micropropagated under ZnO nanoparticles stress.

Thymus species are aromatic plants with diverse applications in food industries and medicine. This study was conducted to evaluate the potential effect of ZnO nanoparticles (NPs) on callus proliferation and thymol and carvacrol production in three Thymus species, that is, T. vulgaris, T. daenensis, and T. kotschyanus, and Zataria multiflora. For this purpose, callus induction was performed on Murashige and Skoog (MS) medium containing different plant growth regulators (PGRs). After optimization of callus growth, the effects of different concentrations of ZnO NPs (100 and 150mgL-1 ) were investigated. MS containing 2mgL-1 of 2, 4-dichlorophenoxy acetic acid (2,4-D) and 1mgL-1 of kinetin (Kin) revealed significantly highest fresh weight (0.18g) of callus in T. kotschyanus. Callus growth rate (0.079mmday-1 ) was found highest in T. vulgaris under similar conditions. Moreover, highest callus induction (92.50%) was achieved by T. kotschyanus in MS containing 2.5mgL-1 of 2,4-D. Regarding the highest content of thymol (22.8mgL-1 ) and carvacrol (0.68mgL-1 ) evaluated by high-performance liquid chromatography, best results were achieved under 150mgL-1 of ZnO NPs in T. kotschyanus and T. daenesis, respectively. This is simple and cost-effective method to be applied on industrial level for production of enhanced secondary metabolites content.

Molecular and cytogenetic assessment of zinc nanoparticles on Vicia faba plant cells.

Abstract Nanotechnology is an emerging multidisciplinary field with a wide range of applications in agriculture, cancer therapy, targeted drug delivery and cosmetic industry. Nevertheless, unspecified release of nanoparticles (NPs) into the ecosystem has raised global concern about their potential toxic effects. In the present study, the effect of different concentrations of ZnO NPs were evaluated on molecular DNA level, on mitotic and meiotic division of Vicia faba plant. The data obtained using ISSR assay showed change in bands number in all tested samples. The highest polymorphic bands recorded are 36 and 34 bands at samples treated with 50.00 and 37.50 μg/mL of ZnO NPs respectively, as compared with untreated plants. In addition to appearance and disappearance of bands in ISSR profiles, a decrease in genetic template stability (GTS) values was recorded with increasing the concentration. The GTS value recorded 58.62% with the highest concentration (50.00 μg/mL); while recorded 67.82% in samples treated with the lowest concentration (6.25 μg/mL) of ZnO NPs. High GTS value indicates that the genome is less prone to alterations in its DNA, whereas low GTS value indicates greater chances of DNA alteration. On the other hand, the cytotoxic effect of ZnO NPs as indicated by inhibiting mitotic and meiotic division and production of chromosomal aberrations such as chromosome breaks was confirmed by their effect on DNA profiles in Vicia faba plant. This study revealed that higher concentrations of Zinc oxide nanoparticles (ZnO NPs) produce genotoxic effects which indirectly can cause health risks to the human populations. Further studies focused over elucidating the fate and behaviour of ZnO-NPs in complex environmental matrices are needed to safeguard ecosystem functioning as well as human kind. However, to the best of our understanding no molecular studies of ZnO-NPs on Vicia faba L. has been reported.

Enhancing the secondary metabolite and anticancer activity of Echinacea purpurea callus extracts by treatment with biosynthesized ZnO nanoparticles

This investigation was done to study the effect of green synthesized ZnO nanoparticles (NPs) on the anticancer activity of callus extracts of Echinacea purpurea in comparison with commercial ZnO microparticles (MPs). Leaf explants of E. purpurea were grown on the Murashinge and Skoog (MS) medium containing different concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D) and naphthalene acetic acid (NAA). Callus induction at optimum concentrations were considered under both light and dark conditions. Among media with diverse concentrations of 2,4-D and NAA, fast-growing friable callus was started within three weeks after culturing on the MS medium containing 2.0 mg . After adding different concentrations of synthesized ZnO NPs and ZnO MPs to the culture medium containing 2 mg , the effect of ZnO NPs on the anticancer activity of plant extracts and callus biomass was found positive contrary to the control and ZnO MPs. However, these extracts did not have any cytotoxic activity on MCF-10 cells and peripheral blood monolayer cells. The frequency and intensity of CD4 expression on peripheral blood monolayer cells was not increased in the presence of all extracts. The highest flavonoid production of the extracts was also achieved in calli treated with different concentration of ZnO NPs. Therefore, it can be concluded that there is a direct relationship between the anticancer activity of E. purpurea and flavonoid contents.