Nanomaterials are structures whose exceptionality is based on their large surface, which is closely connected with reactivity and modification possibilities. Due to these properties nanomaterials are used in textile industry (antibacterial textiles with silver nanoparticles), electronics (high-resolution imaging, logical circuits on the molecular level) and medicine. Medicine represents one of the most important fields of application of nanomaterials. They are investigated in connection with targeted therapy (infectious diseases, malignant diseases) or imaging (contrast agents). Nanomaterials including nanoparticles have a great application potential in the targeted transport of pharmaceuticals. However, there are some negative properties of nanoparticles, which must be carefully solved, as hydrophobic properties leading to instability in aqueous environment, and especially their possible toxicity. Data about toxicity of nanomaterials are still scarce. Due to this fact, in this work we focused on studying of the effect of magnetic nanoparticles (NPs) and modified magnetic nanoparticles (MNPs) on tobacco BY-2 plant cell suspension culture. We aimed at examining the effect of NPs and MNPs on growth, proteosynthesis — total protein content, thiols — reduced (GSH) and oxidized (GSSG) glutathione, phytochelatins PC2-5, glutathione S-transferase (GST) activity and antioxidant activity of BY-2 cells. Whereas the effect of NPs and MNPs on growth of cell suspension culture was only moderate, significant changes were detected in all other biochemical parameters. Significant changes in protein content, phytochelatins levels and GST activity were observed in BY-2 cells treated with MNPs nanoparticles treatment. Changes were also clearly evident in the case of application of NPs. Our results demonstrate the ability of MNPs to negatively affect metabolism and induce biosynthesis of protective compounds in a plant cell model represented by BY-2 cell suspension culture. The obtained results are discussed, especially in connection with already published data. Possible mechanisms of NPs’ and MNPs’ toxicity are introduced.

Atmospheric pressure plasma enhanced chemical vapour deposition (AP-PECVD) of thin films by means of a microwave plasma jet operating with mixtures of argon and tetrakis(trimethylsilyloxy)silane (TTMS) is reported for the first time. In contrast to other siloxy-alkanes that are commonly used for PECVD, the molecule of TTMS (C12H36O4Si5) exhibits a complex and symmetric molecular structure which is presumably essential for a large scale nanostructuring of the films. Deposited films have been characterized by means of electron microscopy (SEM), x-ray spectroscopy (EDX), and infra-red spectroscopy (FTIR). The applied methods demonstrate the prevalent inorganic SiO2-like character of the films and their highly fractalized nanostructure over a wide range of dimension 100–104 nm. Contact angle measurements show the superhydrophobicity of the films, while the dispersive component of the surface energy can be varied in a controlled way by low-frequency amplitude modulation of the excitation power of the MW discharge. The modulation regimes of the jet have been investigated by means of time-resolved optical emission spectroscopy in order to describe the oscillations of plasma parameters e.g. rotational temperature from OH and relative emission of silicon atoms to substantiate the reproducibility of the deposition conditions and to correlate the plasma properties with the resulting film properties.

Using an atmospheric-pressure surface-wave-driven jet, the surfatron, we carried out the surface treatment of the silicon, polyamide, and wood. The changes in surface energy of the samples were determined by the contact angle measurements. Some of the results show rather quick treatment time, probably due to a high power density in the surfatron device.

The influence of the interplay between central ( Q _C ) and secondary ( Q _S ) channel gas flow, as well as delivered microwave power ( P _MW ), during graphene nanosheet synthesis in a dual-channel electrode configuration of a microwave plasma torch at atmospheric pressure by ethanol decomposition was investigated. In the dual-channel configuration, plasma discharge can be sustained, even at high flow rates of ethanol, due to the separation of argon working and carrier gas. The plasma discharge instability was mainly influenced by an increase in the central channel flow, and a minor influence of secondary channel flow was also observed. With respect to the dependence on experimental conditions, the synthesized nanopowder consisted of amorphous carbon and nanocrystalline diamond nanoparticles, defective carbon nanosheets or few-layer graphene nanosheets. The synthesized nanosheets are rectangular in shape with a lateral size of several hundreds of nanometres and a few graphene layers thick, as shown by electron microscopy. Raman and x-ray photoelectron spectroscopy analysis of the synthesized nanosheets showed a good degree of graphitization, low oxygen content and increasing quality of graphene nanosheets with increasing microwave power. The number of defects in the synthesized nanosheets could be decreased by elongation of the graphene nanosheet assembly zone. An increase in the C ₂ /C emission line intensity ratio correlated with a decrease in the number of defects in the graphene nanosheet structure. The achieved conversion yield of ethanol into graphene nanosheets was 8.3%, without negatively affecting the nanosheet quality.

Understanding underlying processes behind the simple and easily scalable graphene synthesis methods enables their large-scale deployment in the emerging energy storage and printable device applications. Microwave plasma decomposition of organic precursors forms a high-temperature environment, above 3000 K, where the process of catalyst-free dehydrogenation and consequent formation of C ₂ molecules leads to nucleation and growth of high-quality few-layer graphene (FLG). In this work, we show experimental evidence that a high-temperature environment with a gas mixture of H ₂ and acetylene, C ₂ H ₂ , leads to a transition from amorphous to highly crystalline material proving the suggested dehydrogenation mechanism. The overall conversion efficiency of carbon to FLG reached up to 47%, three times as much as for methane or ethanol, and increased with increasing microwave power (i.e. with the size of the high-temperature zone) and hydrocarbon flow rate. The yield decreased with decreasing C:H ratio while the best quality FLG (low D/G–0.5 and high 2D/G–1.5 Raman band ratio) was achieved for C:H ratio of 1:3. The structures contained less than 1 at% of oxygen. No additional hydrogen was necessary for the synthesis of FLG from higher alcohols having the same stoichiometry, 1-propanol and isopropanol, but the yield was lower, 15%, and dependent on the atom arrangement of the precursor. The prepared FLG nanopowder was analyzed by scanning electron microscopy, Raman, x-ray photoelectron spectroscopy, and thermogravimetry. Microwave plasma was monitored by optical emission spectroscopy.

Few-layer graphene nanosheets were synthesised from ethanol using a microwave plasma torch. The stability of the discharge permitted us to directly observe and analyse two distinctive structures—a plasma zone and an assembly zone. Important plasma parameters and insights into the chemical processes taking place in these zones were gained using optical emission spectroscopy and digital imaging for a set of experimental conditions. The results of the plasma diagnostics were then correlated with the synthesised material properties, mainly obtained from electron microscopy and Raman spectroscopy.