Biosynthesized Zinc Oxide Nanoparticles Disrupt Established Biofilms of Pathogenic Bacteria

Global emergence and persistence of the multidrug-resistant microbes have created a new problem for management of diseases associated with infections. The development of antimicrobial resistance is mainly due to the sub-judicious and unprescribed used of antimicrobials both in healthcare and the environment. Biofilms are important due to their role in microbial infections and hence are considered a novel target in discovery of new antibacterial or antibiofilm agents. In this article, zinc oxide nanoparticles (ZnO-NPs) were prepared using extract of Plumbago zeylanica. ZnO-NPs were characterized and then their antibiofilm activity was tested against Gram-positive and Gram-negative bacteria. The ZnO-NPs were polydispersed, and the average size was obtained as 24.62 nm. The presence of many functional groups indicated that phytocompounds of P. zeylanica were responsible for the synthesis, capping, and stabilization of ZnO-NPs. Synthesized NPs inhibited the biofilm formation of E. coli, S. aureus, and P. aeruginosa by 62.80%, 71.57%, and 77.69%, respectively. Likewise, concentration-dependent inhibition of the EPS production was recorded in all test bacteria. Microscopic examination of the biofilms revealed that ZnO-NPs reduced the bacterial colonization on solid support and altered the architecture of the biofilms. ZnO-NPs also remarkably eradicated the preformed biofilms of the test bacteria up to 52.69%, 59.79%, and 67.22% recorded for E. coli, S. aureus, P. aeruginosa, respectively. The findings reveal the ability of green synthesized zinc oxide nanoparticles to inhibit, as well as eradicate, the biofilms of Gram-positive and Gram-negative bacteria.

Enhanced Photocatalytic Activity of ZnO–CdS Composite Nanostructures towards the Degradation of Rhodamine B under Solar Light

A simple chemical precipitation route was utilized for the synthesis of ZnO nanoparticles (NPs), CdS NPs and ZnO–CdS nanocomposites (NCs). The synthesized nanostructures were examined for the crystal structure, morphology, optical properties and photodegradation activity of rhodamine B (RhB) dye. The ZnO–CdS NCs showed a mixed phase of hexagonal wurtzite structure for both ZnO NPs and CdS NPs. Pure ZnO NPs and CdS NPs possessed bandgaps of 3.2617 and 2.5261 eV, respectively. On the other hand, the composite nanostructures displayed a more narrow bandgap of 2.9796 eV than pure ZnO NPs. When compared to bare ZnO NPs, the PL intensity of near-band-edge emission at 381 nm was practically suppressed, suggesting a lower rate of photogenerated electron–hole (e−/h+) pairs recombination, resulting in enhanced photocatalytic activity. Under solar light, the composite nanostructures displayed a photodegradation efficiency of 98.16% towards of RhB dye. After four trials, the structural stability of ZnO–CdS NCs was verified.

Biosynthesis Zinc Oxide Nanoparticles Using Senna Occidentalis Leaf Extract and Evaluation of their Cytotoxic Effect on SW480 Colon Cancer Cell Line

ObjectiveIn the present study, we green synthesized ZnO NPs (zinc oxide nanoparticles) from Senna occidentalis leaf extract which were subsequently assessed for their cytotoxic and antioxidant activity on colon cancer SW480 cell line.Results Zinc oxide nanoparticles were characterized by using UV-Vis spectroscopy, X-ray diffractometer (XRD), Particle size analyzer (PSA), Fourier transform infrared spectroscopy (FTIR), Field emission scanning electron microscopy (FE-SEM), Energy-dispersive X-ray (EDS) and atomic force microscope (AFM) analysis. The PSA, XRD and AFM showed 20-50 nm size and nearly cuboidal and irregular shaped of the ZnO NPs. The synthesized ZnO nanoparticles were evaluated for their anticancer activity on human colon cancer cell line (SW480) by using MTT and neutral red uptake assay. The SW480 colon cancer cells were treated with various concentrations of ZnO NPs in the range of 20–100 µg/ml for 2 hrs. The result showed that ZnO NPs could reduce cell viability of SW480 cells up to 50% at the concentration of 100 µg/ml and induce membrane leakage in a concentration dependent manner.ConclusionThe anticancer activity of zinc oxide nanoparticles has showed that these can be used as effective anti-cancer agent against colon cancer cell lines (SW480).

Protective Role of Nrf2 in Zinc Oxide Nanoparticles-Induced Lung Inflammation in Female Mice and Sexual Dimorphism in Susceptibility

Background Zinc oxide nanoparticles (ZnO-NPs) are used in various products such as rubber, paint, and cosmetics. Our group reported recently that Nrf2 protein provides protection against ZnO-NPs-induced pulmonary inflammation in male mice. The present study investigated the effect of Nrf2 deletion on the lung inflammatory response in female mice exposed to ZnO-NPs. Methods Twenty-four female Nrf2−/− mice and the same number of female Nrf2+/+ mice were each divided into three equal groups and each exposed to ZnO-NPs at either 0, 10 or 30 µg/mouse by pharyngeal aspiration. Bronchoalveolar lavage fluid (BALF) and lungs were collected 14 days later to quantify protein level, number of inflammatory cells, and for scoring inflammation histopathologically. The mRNA levels of Nrf2-depedent antioxidant enzymes and proinflammatory cytokine in lung tissue were measured. Results Exposure to ZnO-NPs increased all types of BALF cells and lung inflammation scores in both of female Nrf2−/− and Nrf2+/+ mice, and Nrf2 deletion enhanced ZnO-NPs-induced increase in the number of eosinophils in BALF. Nrf2 deletion enhanced ZnO-NPs-induced downregulation of GR and upregulation of HO-1 and TNFα. Nrf2 deletion decreased mRNA levels of CAT, GcLc and NQO1 and increased that for GcLm and MT-2. ZnO-NPs dose-dependently increased the level of oxidized glutathione (GSSG), and mRNA levels of proinflammatory cytokines/chemokines; KC, MIP-2, IL-6, IL-1β and MCP-1 only in wild-type mice, and Nrf2 deletion decreased total glutathione levels and upregulated the above proinflammatory cytokines/chemokines regardless of level of exposure to ZnO-NPs. Taken together with our previous results in male mice, our results showed a lower susceptibility of females to lung inflammation, relative to males, irrespective of Nrf2 deletion, and that enhancement of ZnO-NPs-induced upregulation of HO-1 and TNFα and downregulation of GR by deletion of Nrf2 is specific to female mice. Conclusion We conclude that Nrf2 provides protection in female mice against increase in BALF eosinophils, probably through down-regulation of proinflammatory cytokines/chemokines and upregulation of oxidative stress-related genes. The study also suggests lower susceptibility to lung inflammation in female mice relative to their male counterparts and the synergistic effects of sex and exposure to ZnO-NPs on mRNA expression of GR, HO-1 or TNFα.

Printed in-plane electrolyte-gated transistor based on zinc oxide

Printed electronics is a reputable research area that encourages the search for simple alternatives of manufacturing processes for low-cost, eco-friendly, and biodegradable electronic devices. Among these devices, electrolyte-gated transistors (EGTs) stand out due to their simple manufacturing process and architecture. Here we report the study of printed electrolyte-gated transistors with in-plane gate architecture (IPGT) based on zinc oxide nanoparticles (ZnO-NPs). The drain, source, and gate electrodes with two different W/L channel ratios were fabricated using a screen-printed carbon-based ink. We also produced a conventional top-gate transistor as a control device, using the same structure as the IPGT described above by adding an ITO strip positioned over the electrolyte as the top-gate electrode. The IPGT with W/L = 5 presented a high mobility of 7.1 cm2V-1s-1, while the W/L = 2.5 device exhibited a mobility of 3.7 cm2V-1s-1. We found that the measured field-effect mobility of the device can be affected by the high contact resistance from the carbon electrodes. This effect could be observed when the geometric parameters of the devices were changed. Furthermore, we also found that the IPGT with W/L = 5 exhibited better values for mobility and transconductance than the top-gate transistor, showing that the IPGTs setup is a good promise for cheap and printed transistors with performance comparable to standard top-gate transistors.

Biofabrication of ZnO nanoparticles using Acacia arabica leaf extract and their antibiofilm and antioxidant potential against foodborne pathogens

Emergence of multidrug resistant pathogens is increasing globally at an alarming rate with a need to discover novel and effective methods to cope infections due to these pathogens. Green nanoparticles have gained attention to be used as efficient therapeutic agents because of their safety and reliability. In the present study, we prepared zinc oxide nanoparticles (ZnO NPs) from aqueous leaf extract of Acacia arabica. The nanoparticles produced were characterized through UV-Visible spectroscopy, scanning electron microscopy, and X-ray diffraction. In vitro antibacterial susceptibility testing against foodborne pathogens was done by agar well diffusion, growth kinetics and broth microdilution assays. Effect of ZnO NPs on biofilm formation (both qualitatively and quantitatively) and exopolysaccharide (EPS) production was also determined. Antioxidant potential of green synthesized nanoparticles was detected by DPPH radical scavenging assay. The cytotoxicity studies of nanoparticles were also performed against HeLa cell lines. The results revealed that diameter of zones of inhibition against foodborne pathogens was found to be 16–30 nm, whereas the values of MIC and MBC ranged between 31.25–62.5 μg/ml. Growth kinetics revealed nanoparticles bactericidal potential after 3 hours incubation at 2 × MIC for E. coli while for S. aureus and S. enterica reached after 2 hours of incubation at 2 × MIC, 4 × MIC, and 8 × MIC. 32.5–71.0% inhibition was observed for biofilm formation. Almost 50.6–65.1% (wet weight) and 44.6–57.8% (dry weight) of EPS production was decreased after treatment with sub-inhibitory concentrations of nanoparticles. Radical scavenging potential of nanoparticles increased in a dose dependent manner and value ranged from 19.25 to 73.15%. Whereas cytotoxicity studies revealed non-toxic nature of nanoparticles at the concentrations tested. The present study suggests that green synthesized ZnO NPs can substitute chemical drugs against antibiotic resistant foodborne pathogens.

Use of Zinc Oxide Nanoparticles as Anticoccidial Agents in Broiler Chickens along with Its Impact on Growth Performance, Antioxidant Status and Hematobiochemical Profile

The impact of zinc oxide nanoparticles (ZnO-NPs) on the pathogenesis of coccidiosis in broiler chickens was tested. A total of 160 1-day-old broiler chicks (Ross 308) were randomly allocated into 4 groups (n = 40). Group 1: unchallenged, unmedicated; Group 2: challenged, unmedicated; Group 3: challenged, supplemented with diclazuril (1 ppm); Group 4: challenged, supplemented with ZnO-NPs (20 ppm). Mixed Eimeria species (E. maxima, E. acervulina, E. mivati, and E. tenella) of a commercial coccidial vaccine (FORTEGRA®) were used to perform the coccidial challenge by 15× of its vaccinal dose on the 14th day of age. Diclazuril and ZnO-NPs supplementation in Group 3 and 4, respectively, reduced the mortality rate due to coccidial challenge to 5.8% compared to 11.9% in Group 2. The growth performance was improved by ZnO-NPs in coccidiosis-infected group (p ≤ 0.05) compared to Group 2 and was comparable to that of Group 3 (p ≥ 0.05). The average oocyst count was lower in Groups 3 and 4 (7.8 × 103 and 14.3 × 103, respectively) than in Group 2 (67 × 103 oocysts). Group 3 had a decreased gross lesion score in duodenum and caecum (p ≤ 0.05) as well as jujenum and ileum (p ≥ 0.05) compared to Group 2; while the average lesion scores of all intestinal parts in Group 4 were significantly decreased (p ≤ 0.05). However, diclazuril was superior to ZnO-NPs in reducing caecal lesion score (p ≤ 0.05). Plasma carotenoids levels were increased by diclazuril (p ≥ 0.05) and ZnO-NPs (p ≤ 0.05) supplementation compared to Group 2. Oxidative stress appeared on the fourth week post-challenge (pc) in Group 2 (p ≤ 0.05) compared to Group 1, while the dietary supplementation with either diclazuril or ZnO-NPs numerically decreased Malondialdhyde (p ≥ 0.05) and statistically increased antioxidant activity (p ≤ 0.05). Both medications significantly improved the PCV%, Hb% and RBCs count on the 6th-day and 4th-week pc (p ≤ 0.05) compared to Group 2, though this improvement was higher significantly in Group 4 than Group 3 on the 6th day pc (p ≤ 0.05). Neither coccidial challenge nor medications had an impact on the total WBCs count as well as organ index, except Bursa of fabricious index that significantly improved by ZnO-NPs on the 4th-week pc compared to Group 2. Coccidial challenge reduced total protein and globulin levels and increased the serum alanine aminotransferase, serum cholesterol, and low-density lipoprotein levels (p ≤ 0.05) compared to Group 1, while those of both medicated groups (Group 3 and 4) were comparable to Group 1 (p ≥ 0.05). In conclusion, ZnO-NPs were found to be as effective as diclazuril against coccidiosis. However, further research is needed to fully comprehend its anticoccidial mechanisms.

Effects of Ambience on Thermal-Diffusion Type Ga-doping Process for ZnO Nanoparticles

Various annealing atmospheres were employed during our unique thermal-diffusion type Ga-doping process to investigate the surface, structural, optical, and electrical properties of Ga-doped zinc oxide (ZnO) nanoparticle (NP) layers. ZnO NPs were synthesized using an arc-discharge-mediated gas evaporation method, followed by Ga-doping under open-air, N2, O2, wet, and dry air atmospheric conditions at 800 °C to obtain the low resistive spray-coated NP layers. The I–V results revealed that the Ga-doped ZnO NP layer successfully reduced the sheet resistance in the open air (8.0 × 102 Ω/sq) and wet air atmosphere (8.8 × 102 Ω/sq) compared with un-doped ZnO (4.6 × 106 Ω/sq). Humidity plays a key role in the successful improvement of sheet resistance during Ga-doping. X-ray diffraction patterns demonstrated hexagonal wurtzite structures with increased crystallite sizes of 103 nm and 88 nm after doping in open air and wet air atmospheres, respectively. The red-shift of UV intensity indicates successful Ga-doping, and the atmospheric effects were confirmed through the analysis of the defect spectrum. Improved electrical conductivity was also confirmed using the thin-film-transistor-based structure. The current controllability by applying the gate electric-field was also confirmed, indicating the possibility of transistor channel application using the obtained ZnO NP layers.