List of Abstracts 2021: POSTER SESSION D
Date: October 21, 2021
Metal oxide nanoparticles are increasingly being produced and will inevitably and up in the aquatic environment. In this work, we focus on the metal oxide nanoparticles CuO. These nanoparticles are used in many commercial products (e.g. CuO nanoparticles in catalysts, semiconductors and chemical sensors).
We focused on acute and reproductive effects of CuCl2 and CuO NPs <50 nm, in particular. Assessment of the impact of selected NPs on important representatives of the aquatic environment. The aim of this study was to investigate the chronic toxicity of the nanoparticles to Daphnia magna and Tubifex tubifex. Selected representatives are an important part of the fish food chain. The effect of the CuO NPs and CuCL2 salt was tested on the growth and reproduction of D. magna in a chronic test scenario according to OECD guidelines 211. Tests with Tubifex tubifex were performed according to method ASTM E1706-04. The concentrations of CuCL2 and CuO NPs tested were as follows: 0.1, 0.5, 1, 5, 10 mg.l-1. Graphpad Prism was used for data visualization and statistics. Based on the chronic toxicity data, time to first brood, time between broods and number of broods per D. magna female were calculated. Dose-response curves were constructed and EC10,20,50 reproduction values were calculated.
Nanoparticles accompany us through every industry, but also in everyday life. This article focused mainly on their occurrence in a real work environment. Measurements of the concentration of nanoparticles from anthropogenic activity were performed, where nanoparticles are generated as unwanted waste. Two plants were selected, in one case it was a nanoparticle based on metals, and in the other it was nanoparticles of organic origin, specifically wood. The article will also mention the possible toxic effect on the environment of emerging nanoparticles. The procedures of ISO / TR 27 628 - Workplace atmospheres - Ultrafine, nanoparticle and nanostructured aerosols - Inhalation exposure characterization and assessment were applied in order to identify the key sites of the companies that produced the largest amount of nanoparticles and finally a proposal was made to provide protective work. funds in an environment with a risk of nanoparticles according to the certified methodology of the Ministry of Labor and Social Affairs.
For additive production, where the material is prepared by applying thin layers, a simplified designation 3D printing has been used.
During this production volatile organic compounds and ultrafine particles are emitted into the air. A number of measurements for a given type of printer with a specific type of thermoplastic are published on this topic. The procedure of our measurement of the concentration of nanoparticles (10-700 nm) and their mean diameters can be called "field", because it took place in a real environment with mass deployment of 3D printing on the principle of FFF / FDM, with the measuring device moving between printers in various premises and activities: - in the production of parts intended for the assembly of printers; - in the manufacture of components for shields during the lockdown period associated with Covid-19; - in the creative workshops and laboratories of Průsa Research a.s.
The aim of these measurements in real situations was to find measures to reduce the concentration of nanoparticles. Evaluation of the results was proceeded according to the ISO / TR 27 628 standard and determined a proposal of measures of a technological and organizational nature to reduce concentrations.
Microalgae and cyanobacteria comprise of broad group of microorganisms that are capable of photosynthesis. Their biomass contains of a wide range of nutrients and secondary metabolites, such as polysaccharides, amino acids, vitamins, terpenes, phenolic compounds, or various lipids. When we obtain such valuable bioactive compounds there is a need to maintain their activity and prolong their shelf life. Encapsulation into nanomaterials is one of the ways to achieve such a thing.
Presented work is focused on extraction of active compounds from chosen microalgae and cyanobacteria biomass and their characterization. Total amount of chlorophylls as well as individual chlorophylls (a and b), carotenoids and antioxidant activity was determined in all types of extracts. Protein content was evaluated in water extracts. Gelatine was material of the choice for nanofiber preparation. Main reason was its good solubility in water as well as everyday use in food industry as well as in cosmetics. Gelatine nanofibers were prepared by the electrospinning method. Prepared nanofibers were tested for their antioxidant activity and short-term stability. As the prepared samples have potential use in cosmetic industry our gelatine nanofibers as well as extracts itself were tested if they alter human cell viability. The MTT assay was performed on HaCaT cell line.
Prepared extracts contained significant amount of chlorophylls and possessed good antioxidant activity. After encapsulation in gelatine nanofibers extracts retain their antioxidant activity. No diminution of activity was observed in short term stability testing. Lastly MTT assay revealed that all nanofibers did not alter cell viability and therefore are suitable for further application in cosmetics.
ACKNOWLEDGEMENTS: This work was supported by Faculty of Chemistry, Brno University of Technology project No. FCH-S-21-7483.
Vitamins are low molecular weight substances that are essential for humans. However, vitamins are often sensitive to oxidation and degradation due to light and temperature during manipulation and storage. They degrade naturally over time and slowly lose their biological activity. These processes can be prevented and one of the possible option is the use of encapsulation techniques. During encapsulation, the active substances are coated into carrier systems which provide adequate physical and chemical protection against the adverse effects of the external environment. The substances gain better stability and retain their functions during processing or storage. The encapsulation also brings other benefits such as improved transport, controlled release, easier handling and more.
The work was focused on the preparation and characterization of liposomal particles containing vitamins. The selected vitamins were two lipophilic ones (cholecalciferol and tocopherol) and two hydrophilic ones (cobalamin and folic acid). Two types of lecithin were used to optimize liposome preparation. The prepared liposomes were characterized by several assays. Liposome size and stability were determined using a colloidal DLS analyzer - ZetaSizer Nano ZS. Furthermore, the encapsulation efficiency and long-term stability of liposomes during storage were tested. For potential application, the liposomes were tested for cytotoxicity on human cells. Determination of cytotoxicity was performed by MTT assay using human Caucasian colon adenocarcinoma CaCO-2. For food application, the prepared liposomes were subjected to model digestion. For further food applications, the liposomes were lyophilized. Some vitamins (such as tocopherol) have antioxidant activity, so they can be used in anti-aging cosmetics. For cosmetic application, the behavior of liposomes in model environments simulating various cosmetic products was investigated.
The results showed that the encapsulation of vitamins prevents their degradation during digestion and storage. The results also showed no cytotoxicity effect, therefore prepared liposomes are promising for further applications. The acquired knowledge can be used in the production of fortified foods, food supplements and anti-aging cosmetic products.
ACKNOWLEDGEMENTS: This work was supported by the project Nr. FCH-S-21-7483 of the Faculty of Chemisty, Brno University of Technology.
The primary function of the wound dressings has been to clean, cover and protect the wound from external environment. They have been applied on injured areas to provide moist environment, protect the wound from infection, remove excess of exudate, avoid maceration and maintain sufficient exchange of gases. The aim of this study was to prepare and characterize bioactive hydrogel and nanofiber wound dressings functionalized by broad spectrum antibiotic drug, ampicillin. Nanostructures were constituted from poly(3-hydroxybutyrate) and hydrogels were alginate and chitosan based.
Nanofibers were assembled by electrospinning and force spinning techniques and their morphology was confirmed by scanning electron microscopy. Prepared materials were analysed for gradual releasing of the incorporated substance into model environments using spectrophotometric methods. Antibacterial activity against model gram-positive (M. luteus) and gram-negative (S. epidermidis, E. coli) bacterial strains was also evaluated. The results showed good antibacterial efficacy of functionalized materials.
Toxicity of the prepared materials were tested by MTT assay on HaCaT cell line, to assess the suitability of materials for further local skin application. Functionalized hydrogel and nanofiber structures with antimicrobial activity showed promising results for local treatment of open wounds.
Domestic boilers are generally characterized by higher emissions of airborne dust. A commonly used secondary method of reducing emissions in the energy sector is a cyclone. However, its wider expansion in households is limited by, among other things, the low efficiency of particle capture below 1 micrometre in diameter, and it is these sizes that dominate in the flue gas of domestic heating devices. By sharply lowering the temperature of the flue gas below the dew point of the vapour, it condenses on all available surfaces. This effect could increase the diameter of the particles, which could be separated with higher efficiency. A change in the numerical distribution of the fine particles with a temperature and thus the supersaturation of the flue gas was sought. The flue gas passed through an impinger filled with water and isopropyl alcohol at three different temperature regimes. The impinger also served to capture the condensate, which was then subjected to morphology analysis using an electron microscope and determination of particle distribution in the condensate.
Knowledge of behaviour of pharmaceuticals as contaminants in nature is essential for their mobility and toxicity in the soils and surface- and ground-water environments. Their migration ability and toxicity can be affected by their interactions with organic matter. In this contribution, sulfapyridine (a sulfanilamide grug used for antibacterial medication) is studied from the point of view of its transport in hydrogels containing humic substances. Agarose hydrogel was used as a model medium for the transport experiments. Standard Elliot soil humic acid (4S102H) puchased from International Humic Substances Society was incorporated into the hydrogel as an active nanomaterial for interactions with drug and potential suppression of their migration and toxicity in soil systems. The method of diffusion couple was applied on the diffusion experiments. Donnor part was saturated by sulfapyridine and acceptor part was free of drug. After connecting of both parts, the time development of concentration profiles in the couple was monitored. The effective diffusion coefficients for the transport of sulfapyridine in hydrogel enriched by humic acids and pure agarose hydrogel were determined and compared. it was found that the transport of drug is influenced by interactions with humic acids which can immobilize partially sulfapyridine in humic structure. Simultaneously, sorption/desorption experiments were realized. Their results confirmed high degree of drug immobilization (60 - 90 % in the dependence on drug concentration).