Vjaceslavs Gerbreders

Penetration of nanoparticles in flax (Linum usitatissimum L.) calli and regenerants.

We demonstrate a method for direct delivery of metal nanoparticles to flax calli and regenerant cells by vacuum deposition of metal nanolayers on powdered hormone followed by dispersal of the combined hormone-metal in medium. The penetration and location of the gold (AuNPs) and silver (AgNPs) nanoparticles in calli and in plant regenerants were confirmed by optical absorption spectroscopy and scanning electron microscopy. We detected a significant effect of the AuNPs and AgNPs on the regeneration type of flax calli.

Reaction of Flax (Linum Usitatissimum L.) Calli Culture to Supplement of Medium by Carbon Nanoparticles

Frequency of callusogenesis, type and capacity of regeneration, cell ploidy, DNA methylation level, histological features, autofluorescence and photobleaching effects were studied in flax calli grown on medium supplemented with different concentrations of carbon (C) nanoparticles. The presence of carbon nanoparticles on medium decreased the percentage calli formation. Detailed histological study led to better understanding of changes in calli caused by nanoparticles. Ploidy variation in calli cells significantly depended on carbon nanoparticle concentration in the medium. Different types of calli regeneration associated with different C nanoparticles concentration in medium were observed: somatic embryogenesis (direct or indirect) or organogenesis. C nanoparticle dose-dependent DNA hypermethylation in flax calli cells were found. Increased repair ability during laser irradiation was found in calli grown on medium with carbon nanoparticles

Case Study of Somaclonal Variation in Resistance Genes Mlo and Pme3 in Flaxseed (Linum usitatissimum L.) Induced by Nanoparticles

Nanoparticles influence on genome is investigated worldwide. The appearance of somaclonal variation is a cause of great concern for any micropropagation system. Somaclonal variation describes the tissue-culture-induced phenotypic and genotypic variations. This paper shows the results of somaclonal variation in two resistance genes pectin methylesterase and Mlo-like protein in all tissue culture development stages, as donor plant, calluses, and regenerants of Linum usitatissimum induced by gold and silver nanoparticles. In this paper, it was essential to obtain DNA material from all tissue culture development stages from one donor plant to record changes in each nucleotide sequence. Gene region specific primers were developed for resistance genes such as Mlo and Pme3 to define the genetic variability in tissue culture of L. usitatissimum. In recent years, utilization of gold and silver nanoparticles in tissue culture is increased and the mechanisms of changes in genome induced by nanoparticles still remain unclear. Obtained data show the somaclonal variation increase in calluses obtained from one donor plant and grown on medium supplemented by gold nanoparticles (Mlo 14.68 ± 0.98; Pme3 2.07 ± 0.87) or silver nanoparticles (Mlo 12.01 ± 0.43; Pme3 10.04 ± 0.46) and decrease in regenerants. Morphological parameters of calluses showed a number of differences between each investigated culture group.

The impact of CdS nanoparticles on ploidy and DNA damage of rucola ( Eruca sativa Mill.) plants

The genotoxic effect of cadmium sulfide nanoparticles (CdSNPs) of different sizes in rucola (Eruca sativa Mill.) plants was assessed. It was confirmed that nanoparticles < 5 nm in size were more toxic than larger particles at an identical mass concentration. Significant differences in cell ploidy, as well as in the mitotic index, were detected between control and treated samples. Differences in the DNA banding pattern between control samples and samples after treatment with cadmium sulfide nanoparticles were significant and detected at different places as the appearance or elimination of DNA fragments. Fluorescence images showed that cadmium sulfide nanoparticles smaller than 5 nm in size can diffuse through the membrane and their presence affects the genetic system of the plant.

Optical Properties of Composite Films Based on Copper Chloride in PMMA Matrix

The composite lms based on PMMA, CuCl2 and photoinitiator were prepared.Transmission spectra of the lms with and without photoinitiator were measured. The holo-graphic gratings were recorded, the sensitivity of the lms and surface structure of gratingswere studied. Microanalysis of the lms was performed in di erent part of structure elementsof grating.

ZnO-nanostructure-based electrochemical sensor: Effect of nanostructure morphology on the sensing of heavy metal ions

ZnO nanostructures are promising candidates for use in sensors, especially in electrochemical sensors and biosensors, due to their unique physical and chemical properties, as well as sensitivity and selectivity to several types of contamination, including heavy metal ions. In this work, using the hydrothermal method, nanostructures of ZnO were synthesized in four different morphologies: nanorods, nanoneedles, nanotubes and nanoplates. To determine the peculiarities of adsorption for each morphology, a series of electrochemical measurements were carried out using these nanostructured ZnO coatings on the working electrodes, using aqueous solutions of Pb(NO3)2 and Cd(NO3)2 as analytes with different concentrations. It was found that the sensitivity of the resulting electrochemical sensors depends on the morphology of the ZnO nanostructures: the best results were achieved in the case of porous nanostructures (nanotubes and nanoplates), whereas the lowest sensitivity corresponded to ZnO nanorods with a large diameter (i.e., low surface-to-volume ratio). The efficiency of sedimentation is also related to the electronegativity of adsorbate: it has been shown that all observed ZnO morphologies exhibited significantly higher sensitivity in detecting lead ions compared to cadmium ions.

Direct formation of nanostructures by focused electron beam on a surface of thin metallic films

This paper describes a method, which allows obtaining metallic nanostructures (MN) by focused electron beam irradiation in scanning electron microscope (SEM) in one fabrication step and without the use of additional chemicals. MN-nanodots were obtained by 30kV SEM on surfaces of various metallic thin films (Al, Cr, Cu, Mo, Ag). The thin films were prepared by direct current magnetron sputtering on Si substrate with 500 nm thickness. The size and shape of the obtained MN were measured with atomic force microscope. The height of the nanodots was up to 500 nm and their width at half height was in a range from 100 to 500 nm. The size of the obtained MN depends on the parameters of electron beam and properties of the metal. Possible mechanisms of MN forming under the influence of focused electron beam are discussed.

Plant Explants Grown on Medium Supplemented with Fe3O4 Nanoparticles Have a Significant Increase in Embryogenesis

Development of nanotechnology leads to the increasing release of nanoparticles in the environment that results in accumulation of different NPs in living organisms including plants. This can lead to serious changes in plant cultures which leads to genotoxicity. The aims of the present study were to detect if iron oxide NPs pass through the flax cell wall, to compare callus morphology, and to estimate the genotoxicity in Linum usitatissimum L. callus cultures induced by different concentrations of Fe3O4 nanoparticles. Two parallel experiments were performed: experiment A, where flax explants were grown on medium supplemented with 0.5 mg/l, 1 mg/l, and 1.5 mg/l Fe3O4 NPs for callus culture obtaining, and experiment B, where calluses obtained from basal MS medium were transported into medium supplemented with concentrations of NPs identical to experiment A. Obtained results demonstrate similarly in both experiments that 25 nm Fe3O4 NPs pass into callus cells and induce low toxicity level in the callus cultures. Nevertheless, calluses from experiment A showed 100% embryogenesis in comparison with experiment B where 100% rhizogenesis was noticed. It could be associated with different stress levels and adaptation time for explants and calluses that were transported into medium with Fe3O4 NPs supplementation.

Controlled growth of well-aligned ZnO nanorod arrays by hydrothermal method

The application prospect of zinc oxide (ZnO) nanostructures largely relies on the ability to grow nanoobjects with necessary geometry. In this study well-aligned ZnO nanorod arrays with a high density and uniformity were successfully synthesized on the glass substrates by a hydrothermal method at low-temperature. The aqueous solutions of zinc nitrate hexahydrate and hexamethylenetetramine was used. The effect of seed layer (obtained by electrochemical method and by vacuum deposition method) on the alignment of ZnO nanorods has been investigated. The morphological properties of the ZnO nanorods were also examined in accordance with varying the magnetron sputtering angle for ZnO seeds deposition. It is also shown that the electric field can control the direction of the growth of ZnO nanorods. Morphological, structural and compositional characterizations of obtained films were carried out by scanning electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction analysis methods.

Amorphous As-S-Se semiconductor thin films for holography and lithography

Electron beam (EB) induced changes in thin films of the amorphous chalcogenide semiconductors As-S-Se have been studied. The experimental results on patterning of As-S-Se film surfaces by EB exposure and following chemical etching are presented. The possibilities of practical application of this material as resists for the production of relief holograms and diffractive optical elements (DOE) are discussed.