Interaction Of ZnO Nanoparticles Research Articles

Interaction of ZnO Nanoparticles with Metribuzin in a Soil–Plant System: Ecotoxicological Effects and Changes in the Distribution Pattern of Zn and Metribuzin

The use of zinc oxide nanoparticles (ZnO NPs), applied as a possible micronutrient source, in conjunction with organic pesticides in agricultural soils has the potential to alter the environmental behavior and toxicity of these chemicals to soil biota. This research examines the joint effects of ZnO NPs and the herbicide metribuzin (MTZ) on phytotoxicity to plants, toxicity to soil microorganisms, and the accumulation of Zn and MTZ in plants. After 23 days, effects on growth, photosynthetic pigment content, and oxidative stress biomarkers in bean plants (Phaseolus vulgaris) and soil enzymatic activities were evaluated. Additionally, the amounts of Zn and MTZ (and the latter’s main metabolites) in soil and plant tissues were quantified. ZnO NPs reduced ammonium oxidase activity and growth among MTZ-stressed plants while reducing photosynthetic pigment levels and enhancing antioxidant enzymatic activities. MTZ had a marginal impact on the availability and accumulation of Zn in plant tissues, although significant effects were observed in some specific cases. In turn, ZnO NPs drastically affected MTZ degradation in soil and influenced MTZ accumulation/metabolization in the bean plants. Our findings indicate that the indirect effects of ZnO NPs, through their interaction with commonly used organic pesticides, may be relevant and should be taken into account in agricultural soils.

Low-field NMR investigation on interaction of ZnO nanoparticles with reservoir fluids and sandstone rocks for enhanced oil recovery

The use of nanoparticles (NPs) can considerably benefit enhanced oil recovery (EOR) by changing the wettability of the rock, improving the mobility of the oil drop, and decreasing the interfacial tension (IFT) between oil and water. Prior to the application of nanoparticles in oil fields, it is essential to conduct measurements at the laboratory scale. However, the estimation of reservoir wettability is difficult in most laboratory experiments. Practicably, ZnO NPs were used to modify the rock surface wettability, lower the IFT at the oil/water interface, and reduce the interaction of chemical adsorption, such as (surfactant) onto reservoir rock surface to solve various challenges in oil production and EOR operations. Upon confining both ZnO-based nanofluid and the crude oil into sandstone, deviations from the corresponding pure bulk dynamical behaviors were observed with low-field nuclear magnetic resonance (LF-NMR) relaxometry. The expected deviations from the pure bulk behaviors were attributed to the well-known confinement effect. The wettability test results before and after surface variations of formation water (FW) with the addition of three different NP concentrations (0.05, 0.075, and 0.1) wt% ZnO reflected significant changes to its wettability. Among the treatments of Berea sandstone cores with ZnO NPs, the percentage of clay-bound H2O/free fluid index was maximum in 1.0 pore volume (PV) NP treatment. The ratio of NMR relaxations, which determines the affinity of fluids toward solids, by the 1.0 PV NP treatment is reported to have the most potential with higher affinity for FW and less affinity for crude oil toward the pore walls. Hence, LF-NMR allows monitoring of nanofluid and crude oil characteristics in the pores of rock samples and may potentially be applied in further EOR studies.

Butea monosperma seed extract mediated biosynthesis of ZnO NPs and their antibacterial, antibiofilm and anti-quorum sensing potentialities

Nanoparticles (NPs) prepared through safer, eco-friendly and natural-based products can be used various applications including antimicrobial and biomedical applications. Quorum sensing (QS) is a complex system for intercellular communication that regulates the expression of many virulence determinants, in the opportunistic Pseudomonas aeruginosa. Thus, the disruption of QS-mediated communication system could be an alternative strategy to combat infection caused by drug resistant P. aeruginosa. In this study, zinc oxide nanoparticles (ZnO NPs) were synthesized by using seed extract of Butea monosperma and further characterized by XRD, SEM and TEM. The biosynthesized ZnO NPs were then subjected to the investigation of their antibacterial, antibiofilm activities as well as the anti-quorum sensing potentialities for biomedical applications. The minimum inhibitory concentration (MIC) value against P. aeruginosa was found 1600 µg/ml, and it was found that ZnO NPs effectively reduced virulence factors Viz. swarming and swimming of P. aeruginosa by 62.8 and 45%, respectively. Exopolysaccharides production was also affected by ZnO NPs which indicate the disruption of biofilm formation. Further, the in silico docking analysis displayed that ZnO NPs efficiently interacted within QS (Las/Rhl) mechanism of P. aeruginosa by binding to the catalytic cleft of LasI synthase (Gly-116-ZnO = 2.8 Å), RhlI synthase (Gly-180-ZnO = 3.7 Å) and transcription receptor protein LasR receptor (Asn-141-ZnO = 2.9 Å), RhlR receptor (Tyr-72-ZnO = 2.6 Å). Thus, it was concluded that the effective interaction of ZnO NPs with Las and Rhl system led to the inactivation of autoinducers such as N-acyl homoserine lactones (AHL) molecules which finally led to the inactivation of QS and down regulation of virulence determinants. Consequently, the present in vitro and in silico results obtained suggest that the synthesized ZnO NPs can be efficiently used as potent antimicrobial agents to prevent the colonization, biofilm formation as well as anti-QS-mediated determinants caused by pathogenic drug resistant bacteria.

Formation of Zn-Al layered double hydroxides (LDH) during the interaction of ZnO nanoparticles (NPs) with γ-Al2O3

Zinc and aluminum layered double hydroxides (Zn-Al LDH) are a common group of major Zn species in various Zn-contaminated soil/sediment environments, yet their formation pathways and underlying mechanisms under varied conditions are not well understood. This study investigated the formation of Zn-Al LDHs through the direct interaction of two solid substrates, ZnO nanoparticles (NPs) and a representative Al oxide, γ-Al2O3. Batch experiments and complementary microscopic and spectroscopic analyses were conducted to elucidate the reaction kinetics and mechanisms, as well as the morphologic and structural evolution of the products. Dissolved Zn and Al concentrations decreased significantly in a dual solid system compared to a single solid system. A bulk Zn-Al LDH phase was found to form under a wide pH range (6.5–9.5). Aside from Zn-Al LDH, γ-Al2O3 was the main remaining solid phase at pH 6.5, whereas ZnO NPs were the main residual solid phases at pH 9.5. Formation of amorphous Zn(OH)2 was also observed at both pH values, likely due to Zn2+ release at low pH and Al(OH)4− adsorption at high pH. It is proposed that the formation of Zn-Al LDH occurs via a dissolution-sorption-coprecipitation process, where the solubility of ZnO NPs or γ-Al2O3 solid phases determines the reaction pathways and kinetics under varied pH conditions. The results from this work revealed the transformation mechanisms for ZnO NPs under conditions from weakly acidic to alkaline pH with highly available Al particles and shed light on the environmental fate of ZnO NPs in Zn or ZnO NP contaminated environments.

Interaction mechanism of insulin with ZnO nanoparticles by replica exchange molecular dynamics simulation

The interaction of ZnO nanoparticles with biological molecules such as proteins is one of the most important and challenging problems in molecular biology. Molecular dynamics (MD) simulations are useful technique for understating the mechanism of various interactions of proteins and nanoparticles. In the present work, the interaction mechanism of insulin with ZnO nanoparticles was studied. Simulation methods including MD and replica exchange molecular dynamics (REMD) and their conditions were surveyed. According to the results obtained by REMD simulation, it was found that insulin interacts with ZnO nanoparticle surface via its polar and charged amino acids. Unfolding insulin at ZnO nanoparticle surface, the terminal parts of its chains play the main role. Due to the linkage between chain of insulin and chain of disulfide bonds, opposite directional movements of N terminal part of chain A (toward nanoparticle surface) and N termini of chain B (toward solution) make insulin unfolding. In unfolding of insulin at this condition, its helix structures convert to random coils at terminal parts chains.

Improvement of dielectric properties of spin coated PMMA-ZnO nano hybrid thin film

ABSTRACTPMMA - ZnO nano hybrid thin film was prepared with different weight ratio of ZnO nanoparticles by spin coating method. The thin films were characterized by SEM, AFM, XRD, FTIR, contact angle and dielectric spectroscopy. The interaction between ZnO and PMMA was studied by Fourier Transform Infra-red (FTIR) spectroscopy. AFM provides the comparison of spatial resolution between pure PMMA thin film and nano hybrid thin film to understand surface morphology and interaction of ZnO nanoparticles with PMMA. The dielectric properties are discussed by interfacial polarization. The main reason for improvement of dielectric properties is the formation of new crystalline boundaries.

Sensitization of ZnO nanoparticle by vitamin B12: Investigation of microstructure, FTIR and optical properties

Vitamin B12 (VB12) as a biomolecule was successfully applied to modify the as-synthesized ZnO nanoparticles (NPs). VB12–ZnO conjugate was fabricated by a solution based method, the phase component of which was independent of the modification process, as shown by X-ray diffraction (XRD) analysis. The amount of loaded VB12 on ZnO NPs was measured by thermal gravimetry (TGA) to be∼25wt.%. Fourier transform infrared (FTIR) spectroscopy was used to probe the interaction of ZnO NPs with VB12. Although the sensitization process did not cause the appearance of any intense new peak in the FTIR results, the traces of a new band at 756cm−1 and also the intensification of the peak at 3411cm−1 (in comparison to ZnO spectrum) confirmed the formation of some new bands between NPs and VB12 molecules. The UV–vis spectroscopy revealed that VB12–ZnO conjugate absorbed light irradiation at around 272, 380 and 454nm. The third one is situated in the visible light region, originating from the conjugation between ZnO NPs and the functional ring of VB12. The photoluminescence (PL) behavior was affected by the sensitization process, shifting the PL peak of ZnO NPs toward a higher wavelength and increasing its intensity.

Comparative studies of synthesis, stability and antibacterial activity of zinc oxide nano-particles

Research related to the antibacterial activity of nanoparticles will enable new developments in the field of nanomedicine. Targeted drug delivery, diagnostics, magnetic resonance, imaging etc., are possible because of the biological cell interactions of the nanoparticles. The present study focuses on one such interaction of ZnO nanoparticles. The antibacterial activity and stability of ZnO nanoparticles synthesised using different methods was investigated. The inhibitory effect of ZnO nanoparticles against Escherichia coli, Proteus vulgaris, Pseudomonas, Propionibacterium acnes, Bacillus, Klebsiella and Staphylococcus aureus was tested by agar well diffusion method. The zones of inhibition for all the selected bacterial strains were measured. The ZnO nanoparticles synthesised by the different methods were effective against all the organisms tested and the nanoparticles were quite stable.

Serum albumin enhances the membrane activity of ZnO nanoparticles

We investigate the effect of serum albumin on the interaction of ZnO nanoparticles with DOPC lipid membranes and show that the size-stabilizing effect of the protein corona enhances their interaction with lipid membranes, which manifests, in part, as an increased ordering in the lipid packing.

Interaction of ZnO Nanoparticles with Microbes—A Physio and Biochemical Assay

The antibacterial activity of ZnO nanoparticles (nano ZnO) on various microorganisms has been investigated in this study and acting mechanism is proposed for E. coli a model organism by analyzing the growth, permeability and morphology of the bacterial cells. The experimental results indicated 1 mmoL (81.4 microg) nano ZnO could completely inhibit the growth of 10(7) cfu/mL bacterial cells in liquid Luria-Betrani medium. In the biochemical study, it has been observed that, nano ZnO resulted in the leakage of proteins. Chemiluminescence assay proved the generation of the reactive oxygen species into active state. When the cells of E. coli were exposed to nano ZnO, many pits were observed in bacterial cells by TEM and Fluorescence microscopy and the cells were found to be fragmentary. Released zinc ion from has been monitored by AAS. It suggested that nano ZnO is able to destroy the permeability of the bacterial membranes. Our study demonstrated that nano ZnO damages the structure of bacterial cell membrane and depressed the activity of some membranous enzymes by ROS production which caused E. coli bacteria to die eventually.

Potential environmental influence of amino acids on the behavior of ZnO nanoparticles

The fate of nanomaterials when they enter the environment is an issue of increasing concern and thus it is important to know how they interact with natural organic molecules since this may have a significant impact on the particles’ behavior. Because of our poor knowledge in this regard, the interaction of ZnO nanoparticles with amino acids of contrasting surface charge, including Histidine (HIS), Glycine (GLY), Aspartic acid (ASP) and Glutamic acid (GLU) which occur commonly in natural habitats, such as the plant root zone, was investigated over a range of pH conditions and concentrations. The addition of the individual amino acid led to significant changes in nanoparticle colloidal zeta potential stability, particle size distribution and the extent of agglomeration. Variations in pH resulted in considerable changes in nanoparticle surface charge and hydrodynamic size. In general, the particle size distribution decreased as the amino acid concentration increased, with more acidic conditions exacerbating this effect. In addition, increased concentrations of amino acids resulted in more stable nanoparticles in aqueous suspensions. Histidine had the greatest effect on colloidal stability, followed by Glycine, Aspartic acid and finally Glutamic acid. This study illustrates how nanoparticle behavior may change in the presence of naturally occurring amino acids, an important consideration when assessing the fate of nanoparticles in the environment. Additionally, utilization of amino acids in industrial processes could reduce particle agglomeration and it could lead to a way of employing more sustainable reagents.