Fakulta chemická

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The Interaction of Microplastics and Microbioplastics with Soil and a Comparison of Their Potential to Spread Pathogens
(MDPI, 2024-06-18) Trojan, Marek; Koutný, Marek; Brtnický, Martin; Holátko, Jiří; Zlámalová Gargošová, Helena; Fojt, Jakub; Procházková, Petra; Kalčíková, Gabriela; Kučerík, Jiří
Microplastics contribute to various environmental issues and serve as carriers for a wide range of toxic compounds such as pesticides, pharmaceuticals, and metal ions. Consequently, there is a gradual shift towards replacing them with biodegradable plastics (bioplastics). However, biodegradable plastics require specific conditions for complete biodegradation, and their biodeterioration often leads to the rapid production of smaller fragments, known as microbioplastics. In this review, we summarize selected issues related to the impact of plastic particles on soil properties and the soil microbiome. Findings from numerous studies indicate that both microplastics and microbioplastics induce adverse changes in soil microbiology, potentially increasing the abundance of soil-borne pathogens. Based on these observations, we argue that plastic particles could serve as carriers for colonies of soil-borne pathogens. Furthermore, the use of bioplastics may exacerbate this issue due to their easier and faster formation, increased support for biofilms, and more pronounced adverse effects on soil biota. However, further research is necessary to either substantiate or refute this perspective.
Photoelectric Properties of Solar Cells Based on Perovskites
(Czech Technical University in Prague, 2018-03-13) Novák, Vítězslav; Vanýsek, Petr; Weiter, Martin
Here we discuss materials and construction of particular solar cells that could be possible replacement for the current silicon-based photovoltaic cells, and methods of studying their performance. Solar cells based on the general perovskite structure (ABX3) attracted in recent years much attention. These materials, due to the possible variability of both cations and anions in their composition, offer almost endless possibilities for synthetic preparation. For the active layer of a solar cell is often used the CH3NH3PbI3-2Cl2 perovskite structure, i.e., a structure containing an organic component. We have built photovoltaic cells with such an active layer and tested them by static and dynamic methods using the unique photoelectric research instrument by Zahner using the method CIMPS (Controlled Intensity Modulated Photocurrent Spectroscopy).
Translational Studies on the Potential of a VEGF Nanoparticle-Loaded Hyaluronic Acid Hydrogel
(MDPI, 2021-05-22) O’Dwyer, Joanne; Murphy, Robert; González-Vázquez, Arlyng; Kovářová, Lenka; Pravda, Martin; Velebný, Vladimír; Heise, Andreas; Duffy, Garry P.; Cryan, Sally Ann
Heart failure has a five-year mortality rate approaching 50%. Inducing angiogenesis following a myocardial infarction is hypothesized to reduce cardiomyocyte death and tissue damage, thereby preventing heart failure. Herein, a novel nano-in-gel delivery system for vascular endothelial growth factor (VEGF), composed of star-shaped polyglutamic acid-VEGF nanoparticles in a tyramine-modified hyaluronic acid hydrogel (nano-VEGF-HA-TA), is investigated. The ability of the nano-VEGF-HA-TA system to induce angiogenesis is assessed in vivo using a chick chorioallantoic membrane model (CAM). The formulation is then integrated with a custom-made, clinically relevant catheter suitable for minimally invasive endocardial delivery and the effect of injection on hydrogel properties is examined. Nano-VEGF-HA-TA is biocompatible on a CAM assay and significantly improves blood vessel branching (p < 0.05) and number (p < 0.05) compared to a HA-TA hydrogel without VEGF. Nano-VEGF-HA-TA is successfully injected through a 1.2 m catheter, without blocking or breaking the catheter and releases VEGF for 42 days following injection in vitro. The released VEGF retains its bioactivity, significantly improving total tubule length on a Matrigel(R) assay and human umbilical vein endothelial cell migration on a Transwell(R) migration assay. This VEGF-nano in a HA-TA hydrogel delivery system is successfully integrated with an appropriate device for clinical use, demonstrates promising angiogenic properties in vivo and is suitable for further clinical translation.
Degradation of P(3HB-co-4HB) Films in Simulated Body Fluids
(MDPI, 2022-05-13) Vodička, Juraj; Wikarská, Monika; Trudičová, Monika; Juglová, Zuzana; Pospíšilová, Aneta; Kalina, Michal; Slaninová, Eva; Obruča, Stanislav; Sedláček, Petr
A novel model of biodegradable PHA copolymer films preparation was applied to evaluate the biodegradability of various PHA copolymers and to discuss its biomedical applicability. In this study, we illustrate the potential biomaterial degradation rate affectability by manipulation of monomer composition via controlling the biosynthetic strategies. Within the experimental investigation, we have prepared two different copolymers of 3-hydroxybutyrate and 4-hydroxybutyrate-P(3HB-co-36 mol.% 4HB) and P(3HB-co-66 mol.% 4HB), by cultivating the thermophilic bacterial strain Aneurinibacillus sp. H1 and further investigated its degradability in simulated body fluids (SBFs). Both copolymers revealed faster weight reduction in synthetic gastric juice (SGJ) and artificial colonic fluid (ACF) than simple homopolymer P3HB. In addition, degradation mechanisms differed across tested polymers, according to SEM micrographs. While incubated in SGJ, samples were fragmented due to fast hydrolysis sourcing from substantially low pH, which suggest abiotic degradation as the major degradation mechanism. On the contrary, ACF incubation indicated obvious enzymatic hydrolysis. Further, no cytotoxicity of the waste fluids was observed on CaCO-2 cell line. Based on these results in combination with high production flexibility, we suggest P(3HB-co-4HB) copolymers produced by Aneurinibacillus sp. H1 as being very auspicious polymers for intestinal in vivo treatments.
Facile Preparation of Porous Microfiber from Poly-3-(R)-Hydroxybutyrate and Its Application
(MDPI, 2020-01-20) Kundrát, Vojtěch; Skoumalová, Petra; Márová, Ivana
In this study, we described the development of a simplified wet spinning method of the production of a novel type of porous continuous fiber based on poly-3-(R)-hydroxybutyrate (PHB). The principle of this method is precipitation of PHB dissolved in chloroform solution into the ethanol precipitation bath. The influence of various PHB concentrations and feed rates on specific surface area (measured by nitrogen absorption method) was studied. Materials were also characterized by SEM. Surface areas of fibers achieved by wet spinning were in the range of tens of m(2).g(-1), and the biggest surface area value was 55 m(2).g(-1). The average diameter of fibers was in the range of 20-120 mu m and was dependent on both PHB concentration and feed rate. Optimum conditions for reaching stable fibers of high surface area were 3-5 % w.t. of PHB and feed rate 0.5-3 ml.h(-1). Fibers were functionalized by adsorption of some natural plant extracts. The incorporation of active substances into fibers was confirmed by infrared spectroscopy. High antioxidant and antimicrobial effect of PHB-fibers with cloves extract was found, as well as excellent long-term stability and optimal dynamics of the release of active compounds. The newly produced material would be applicable in pharmacy, cosmetics, and wound healing.

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