Seznam abstraktů 2019: POSTEROVÁ SEKCE D

In the last years, the nanosized noble metal (gold, silver) nanostructures became increasingly in the focus of interest in the sensor and medical researches due to their unique properties. Because of their outstanding electrical, magnetic and optical properties, they can be the basis of potential biosensors and the intense interest is directed towards the feasible role of gold in medical diagnostics and human therapies [1,2]. In our research group, we have been paying close attention to the development of biocompatible syntheses of plasmonic Au nanoparticles (NPs) and fluorescence Au nanoclusters (NCs) as well as the characterization of the produced gold/biomolecule hybrid systems: study the relationship between the structure and their optical properties and investigation of their potential utilizations. These different nanostructures can be synthesized depending on the molar ratio of gold precursor and the bioligand [3]. Small ligand excess results the formation of plasmonic NPs with diameter larger than 2 nm. In contrast, at high biomolecule excess sub-nanometer sized fluorescent clusters are formed (d < 2nm). The proteins are the well-known reducing and stabilizing agents during the “green” synthesis methods. For the study of cytotoxicity, some well-known protein-stabilized Au NCs were synthesized. The bovin and human serum albumin (BSA and HSA), the γ-globulin immunoprotein (γG), the lysozyme (LYZ) were used as stabilizing and reducing agent. The synthesized red-emitter Au NCs were widely analysed by spectrofluorimetry, FT-IR and CD spectroscopy, HRTEM, DLS and ζ-potential measurements. The toxicity of these nanomaterials were tested on several different healthy and tumor human (e.g. A459, hCMEC/D3, HUT-98) with colorimetric dye conversion assay (MTT).

Acknowledgement
The Ministry of Human Capacities, Hungary grant 20391-3/2018/FEKUSTRAT is acknowledged. The research was supported by by the National Research, Development and Innovation Office-NKFIH through the project GINOP-2.3.2-15-2016-00038 and FK131446 and FK132067. Sz. Veszelka gratefully admits the financial support of the Premium Postdoctoral Research Program of the Hungarian Academy of Sciences.

References
[1] D. Ungor, E. Csapó, B. Kismárton, Á. Juhász, I. Dékány, Nucleotide-directed syntheses of gold nanohibrid systems with structure-dependent optical features: Selective fluorescence sensing of Fe3+ ions, Colloids and Surfaces B: Biointerfaces 155, 135-144 (2017), doi: 10.1016/j.colsurfb.2017.04.013

[2] D. Ungor, K. Horváth, I. Dékány, E. Csapó: Red-emitting gold nanoclusters for rapid fluorescence sensing of tryptophan metabolites, Sensor & Actuators B 288 (2019) 728-733. doi: 10.1016/j.snb.2019.03.026

[3] D. Ungor, I. Dékány, E. Csapó: Reduction of Tetrachloroaurate(III) Ions With Bioligands: Role of the Thiol and Amine Functional Groups on the Structure and Optical Features of Gold Nanohybrid Systems, Nanomaterials 9 (2019) 1229-1247.
doi: 10.3390/nano9091229

MXenes are a new class of 2D carbides or nitrides which have been considered chiefly as promising energy storage materials. As these advanced materials are hydrophilic with good biocompatibility and near-infrared (NIR) absorption, their potential biomedical applications are beginning to grow. Here, we report cytotoxicological study of Nb2C MXene. We have applied an environmentally friendly protein-driven delamination which results in highly colloidally stable MXene dispersion at physiological conditions. To ascertain the cytotoxicity of this material, we have utilized flow-cytometry based assays of viability, cell cycle progression and mitochondrial membrane potential (MMP) using NIH3T3 mouse fibroblast and human lung adenocarcinoma cells A549. There are no evident toxic effects on both cell lines up to highest concentrations tested (400 µg/ml for viability and cell cycle and 200 µg/ml in case of MMP). This work shows a novel approach to MXene delamination which results in highly biocompatible dispersion of this material.

Anchoring photoactive nanoparticles (NPs) on the surface of natural phyllosilicate is considered to be a useful way to prevent the spread of free NPs into the environment, and the number of studies focused on photoactive nanocomposites of "phyllosilicate/NPs" type is still growing. However, stability of the photoactive nanocomposites and environmental risks based thereon are commonly not reported or - in a few exceptional cases - the stability is judged solely on the basis of leaching tests in biologically blank water.
In our research, the phytotoxicity of kaolinite/ZnO nanocomposites containing 10, 30, and 50 wt.% of in situ prepared ZnO NPs was tested on white mustard. Also the accumulation of Zn in plant tissues and translocation of Zn from roots to leaves of false fox-sedge were studied. We observed higher phytotoxicity of the nanocomposites and higher uptake of Zn by plants from the nanocomposites compared to pristine ZnO NPs. This behavior can be attributed to the suppressed agglomeration of ZnO NPs in nanocomposites, which is seen as an advantage in terms of photocatalysis. Our results suggest that this advantage might be a disadvantage from a toxicological point of view. Obtained data also show the impossibility to simulate the behavior of nanocomposites using pristine ZnO NPs. Further research is strongly needed.
This work has been funded by the Ministry of Education, Youth and Sports of the Czech Republic, projects numbers SP2019/31, LQ1602 (National Programme of Sustainability II - IT4Innovations excellence in science), and CZ.02.1.01/0.0/0.0/16_019/0000738 (European Regional Development Fund project Centre for Experimental Plant Biology).

Undeniable benefits of engineered nanomaterials might be discredited by their potential enhanced or unexpected toxicity arising from nano-specific properties and behavior. An analysis of the applicability of the traditional chemical risk assessment approach in nanomaterials revealed high levels of uncertainty in both hazard characterization and exposure assessment due to the lack of relevant validated methods and reliable data. This indicates the limited capability of the conventional risk assessment approach to ensure the safe use of nanomaterials. Based on the identified uncertainties, the control banding approach was proposed as a suitable tool for preliminary qualitative risk assessment of nanomaterials in occupational settings. Control banding categorizes hazard and exposure into levels referred to as bands. The combination of the hazard and exposure bands results in a risk band determining the necessary degree of control and regulatory measures. To decrease the number of cases where, based on the precautionary principle, unavailable experimental or field data would lead to the assignment to the highest hazard category requiring costly exposure control, screening evaluation of nanomaterial toxicity was proposed as an additional decision criterion. For this purpose, a battery of in vitro toxicological assays enabling screening evaluation of potential toxic effects of NMs was proposed. The assays evaluate endpoints covering basic toxic effects of substances (cytotoxicity, genotoxicity), as well as known nonspecific mechanisms of toxicity typical for nanomaterials (oxidative stress, inflammation). The proposed risk management strategy is intended to assist small and medium-sized enterprises to implement adequate measures to ensure employee safety.

This pilot study deals with the detection of metal-based solid particles in the human ejaculate and their possible connection with infertility. Ten samples provided by cytogenetics department, CGB Laboratory, a.s. in Ostrava - Vítkovice, were analysed by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDS) and Raman microspectroscopy. Metal-based particles, particularly those containing iron, aluminium, copper, zinc, chromium, titanium and nickel, were detected in the samples. At the same time, titanium compounds and calcium carbonate were found. Many of these substances have already been shown to have a negative effect on the living organism. Based on the information found, there might be some dependence between the presence of solid metal particles in the ejaculate and male fertility impairment.

Humic acids are common substances with supramolecular structure commonly contained in the soil and water ecosystem. It is form by gradual decomposition of plant residues and dead organisms. They are among the most widespread compounds in the world that contain a huge amount of carbon in its structure and its structure contains a lot of different functional groups but mainly a huge amount of carboxyl groups.
Humic substances are known as well for its abilities of different binding ways - it can be ion exchange, hydrogen bridge formation, coulombic interactions, hydrogen bridges, van der Waals interactions, hydrophobic interactions, absorption, etc. In the nature they are responsible for binding of huge amount of pollutants - heavy metals, pesticids, herbicids, dyes, medicament, etc.
The purpose of this work is to measure the decrease of selected initial concentrations of the common medicament ibuprofen with two samples of different humid acids and a soil sample as well. The obtained absorption samples will undergo a desorption experiment under the same time conditions. The output of the work will also monitor the ratio between the amount of absorbed and desorbed ibuprofen and compare the different absorption substrates. The results can provide more details about the stability of ibuprofen-humic complexes and the mobility of ibuprofen in systems containing humic substances.

An increase in the use of nanomaterials (NM) has been witnessed in many areas of human life. Therefore, assessment of genotoxicity of NM and nanoparticles (NP) is one of the main objectives of genetic toxicology. Despite this fact, human cytogenetic studies following the exposure to NP are still rare. Moreover, no relevant information on possible differences in sensitivity to NP related to gender is available.
In this study we periodically (in September 2016, 2017 and 2018; pre-shift and post-shift each year) analyzed a group of workers (both genders), working long time in nanocomposites research, and matched controls. Aerosol exposure monitoring of particulate matter including nano-sized fractions was carried out during working shift. Micronucleus assay using Human Pan Centromeric probes, was applied to distinguish, besides the frequency of total MN in binucleated cells (BNC), also other types of chromosomal damage (losses and breaks). Moreover, whole-chromosome painting (WCP) for autosome #1 and both gonosomes (X and Y) were applied in third sampling period (2018) with the aim to identify the particular structural and numerical chromosomal aberrations.
Obtained results showed: (i) differences in the risk of exposure to NP related to individual working processes (welding, smelting and machining); (ii) differences in chemical composition of nano-fraction; (iii) no effect of chronic exposure of NP (total MN) opposite to significant effect of acute exposure; (iv) gender-related DNA damage differences (females seem to be more sensitive to chromosomal losses). Additional data from WCP suggested increased frequency of numerical aberrations in gonosomes.

The use of nanomaterials (NMs) in different areas has been rising for more than a decade. Along with this growth, there is visible development of different testing tools and approaches for measuring the actual size of nanomaterials in biological systems. Test conditions during in vitro toxicological assays are different from the standard conditions under which nanomaterials are characterized and careful evaluation of results is needed. The unique properties and range variety of NMs require the close look how the NMs behave in different dispersion medium over time. In this study we present the results of five types of well-characterized NMs (TiO2: NM-101 and NM-103; SiO2: NM-200; Ag: NM-300K and NM-302) of specific size and shape. The hydrodynamic size and Zeta potentials in suspensions were measured using a dynamic light scattering technique (DLS) (Zetasizer Nano ZS, Malvern, UK). The DLS method is suitable for spherical particles; nevertheless, all samples were measured in order to obtain a rough insight into agglomerate formation in the medium. NM300, NM302, and NM200 aggregated rapidly in the media, thus the cells would be most likely exposed to settled big aggregates then small clusters or individual particles. More stable NMs (NM100 and NM103) showed slight grow along with cultivation time or concentration corresponding to cluster formation. Cells exposed to those NMs would be in contact with small clusters and aggregates of NMs. Measured zeta potentials fluctuated around the stability limit corresponding to observed aggregation. This work was supported by the MEYS CR (LO1508).

Liposomes are versatile systems for drug delivery. They are utilized in various industries such as pharmaceutical, food industry and cosmetics. Even though they are capable to encapsulate both hydrophilic and lipophilic compounds, they can be modified using cholesterol, proteins and polymers to enhance their properties.
Presented work is focused on development and preparation of PHB-liposomes particles with different PHB content as well as PHB nanofibers. Characterization in terms of particle size, polydispersity index, colloidal stability and long-term stability were done. Sun protection factor was measured, too. Electron microscopy techniques (SEM, cryoTEM) were used to observe structure of prepared materials. To assess whether prepared particles are suitable for further application in cosmetics, MTT and LDH cytotoxicity assays on HaCaT cell line were carried out.
Our goal was to prepare and characterize PHB containing liposomes and nanofibers for potential application in cosmetic, pharmaceutical and food industry. Prepared particles were stable and had proper properties to be used as vehicles. Cytotoxicity assays showed that all materials were nontoxic to HaCaT cell line and, therefore, they can be ceded for further cytotoxicity as well as genotoxicity testing and in future potentially applicable in cosmetic industry.

Investigations of the biological effects of nanomaterials are important for assessing the risk of nanotechnology products. The present study includes the comparative investigation of the localization of core-shell gold hybrid nanostructures and native titanium dioxide nanoparticles. Changes in biochemical parameters of the treated rats in comparison to control animals were observed depending on the type of nanoparticles used. The exposure did not cause lethality, substantial behavior deviations, water and food consumption, pathomorphology of the internal organs. Besides, this study includes the investigation of biological effects of metal nanoparticles after exposure of mammalian cells. Dose- and time-dependent changes in cell viability after exposure to gold hybrid nanostructures and native titanium dioxide nanoparticles were estimated by MTT test.

This contribution deals with preparation of functional interdigited flexible sensors for room temperature operation. The fabrication comprises the utilization of promising technology such as inkjet printing and the deposition of copper(II) acetylacetonate as a ultrathin sensing layer. The inks were prepared by dispersion formation in co-solvent system. The ink composition was developed on the basis of viscosity and surface tension optimization by the addition of polymeric steric surfactant. The printing process was optimized with the help of non-dimensional criteria. To obtain the best possible shape and resolution various parameters such as surface modification, thermal reduction atmosphere, annealing condition, setting of inkjet printer, Ink concentration and viscosity, sheet resistance were investigated. Printed pattern and motifs were characterized by profilometry, microscopy and by resistance measurement to further enhance the quality of printing. The sensitivity of the prepared sensors was demonstrated and studied by measuring the response to saturated vapors at room temperature to improve sensor performance by optimization. Obtained sensitivity of prepared sensors is very promising for detection of organic vapor detection at room temperature. Moreover, other big promising advantage of prepared sensors is their flexibility.

The stability of nanoparticles in aquatic environment plays an important role for their environmental and biological application. The storage time has strong impact on the stability of zinc and copper nanoparticles (ZnONPs and CuNPs). The effect of the storage time was studied over time and the results showed a change in morphology of synthesized NPs. The time stability study was divided into three parts: short-term (0 - 72 h), medium-term (16 days) and long-term (5 months). In the case of CuNPs the SEM picture revealed the presence of crystal structure. This can be explained as the CuNPs surface layer was oxidized and the crystals on surface are copper oxides. Similar study was conducted on ZnONPs, but in shorter time scale (1 - 3 days). As in the case of CuNPs, ZnONPs showed the same tendency to crystalize. We can conclude that storage time and conditions have a strong impact on the NPs stability.

This work is focused on studying the antimicrobial effect of silver nanoparticles made by green synthesis. For the green synthesis, extracts from Salvia officinalis were used. Four different temperatures (20, 40, 60, 80 °C) were used to prepare the extracts from the plant material. The antimicrobial capability of the AgNPs was assessed using different yeasts (Saccharomyces cerevisiae, Zygosaccharomyces bailii), gram-positive (Lactobacillus plantarum, Listeria innocua, Staphylococcus Aureus) and gram-negative (Escherichia coli, Acetobacter aceti) bacterial strains. The range of AgNPs concentrations 0-2,500 µg/mL were tested. The antimicrobial effect was studied using two methods: 1) the viable cell count method and 2) the inhibition zone method. The method of direct counting showed a small inhibitory effect (inhibition at concentrations 1,250 and 2,500 µg/ml) only for E. coli, Z. bailii and S. cerevisiae. The inhibition zone results displayed better antibacterial activity of the silver nanoparticles (inhibition at all concentrations - 50, 100, 150 and 200 µg/mL) prepared by using the extract obtained at 20 ºC against E. coli and S. aureus.

Settled road dust was examined to detect the presence of organic compounds. Samples were collected from a road surface near a busy road junction in the city of Ostrava, Czech Republic, once a month from May to October. The six collected samples were analyzed by gas chromatography with mass detection. The correlation analysis divided the analyzed compounds into three distinct groups. The first group, positively correlated with the traffic count consisted of phenanthrene, acenaphthene, indenol (1,2,3-cd) pyrene, benzo(k)fluoranthene, benzo(a)pyrene, benzo(ghi)perylene, benzo(a)anthracene and chrysene, all positively correlated with each other. The second group of compounds, positively correlated with each other but negatively with the traffic count, consisted of dibenzo(ah)anthracene, naphthalene, anthracene, fluoranthene, acenaphthene and fluorene. The third group consisted only of pyrene, which had a positive correlation with most of the compounds from the second group apart from dibenzo(ah)anthracene and was not correlated with the traffic count in any way.

Currently, more and more emphasis is placed on improving the air quality and promoting alternative methods of household heating, including the use of biomass. Although these combustion processes are considered to be environment-friendly, the fine and ultra-fine particles are also produced in these cases, which can have a negative impact on human health. The paper presents the results of experimental biomass combustion, where the concentrations and generated particle sizes were monitored during the process. In particular, selected combustion parameters were taken into account such as temperature, amount of oxygen, etc., which have a significant influence on particle formation. The particles were sampled during the measurements with the aim to determine their morphology and chemical compositions. The gathered results are intended to be used for the design of the technical measure based on the principle of temperature stabilization, leading to reducing the concentration of fine and ultra-fine particles produced by small combustion devices.