Pokročilé polymerní materiály a kompozit

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Photocatalytic Microplastics "On-The-fly" Degradation via Motile Quantum Materials-Based Microrobots
(Wiley-VCH, 2023-05-16) Jančík Procházková, Anna; Jašek, Vojtěch; Figalla, Silvestr; Pumera, Martin
Nano/micro-plastics pollution is an emerging global concern. A variety of biodegradable polymers have been synthesized to enhance the degradation of plastic materials and thereby avoid their accumulation in the environment. However, even biodegradable polymers can accumulate in environments under specific conditions and present a potential hazard. Here, antimony sulfide-based microrobots decorated with magnetite nanoparticles are designed for microplastics degradation. The propulsion of microrobots is enabled by two independent orthogonal physical modes via magnetic field and via light irradiation. Due to phoretic interactions, the microrobots exhibit affinity toward poly(3-hydroxybutyrate) (PHB) and poly(lactic acid) (PLA) microplastics, which enables subsequent transport of the microplastics in a transversal rotating magnetic field. The photocatalytic activity of Sb2S3 quantum material provides microrobots with the ability to degrade the microplastics under UV light irradiation in the "on-the-fly" regime without the need for any fuel. This proof-of-concept work shows efficient capture, transport, and photocatalytic degradation of microplastics and paves the way toward their elimination, especially in water environments.
Dynamic Responsive Formation of Nanostructured Fibers in a Hydrogel Network: A Molecular Dynamics Study
(Frontiers Media, 2020-02-26) Žídek, Jan; Milchev, Andrey; Jančář, Josef
In an effort to study natural fiber formation, such as, e.g., spider silk, we present a model, which is capable of forming biomimetic fibrillar nanostructure from a hydrogel micellar network. The latter consists of interacting atomic groups which form cores of micelles, and of flexible chains forming the shells of the micelles. Micelles are connected in a compact network by linearly stretched chains. The structural elements of the network can be transformed during deformation from micellar into fibrillary type and their evolution is found to depend significantly on strain rate. Our model suggests a set of conditions suitable for the formation of nanostructured fibrillar network. It demonstrates that a fibrillar structure is only formed upon sufficiently fast stretching while, in contrast, the micellar gel structure is preserved, if the material is pulled slowly. We illustrate this key aspect by a minimalistic model of only four chains as part of the whole network, which provides a detailed view on the mechanism of fibril formation. We conclude that such a simplified structure has similar functionality and is probably responsible for the formation of nano-structured molecular fibrils in natural materials.
Assessing Lettuce Exposure to a Multipharmaceutical Mixture under Hydroponic Conditions: Findings through LC-ESI-TQ Analysis and Ecotoxicological Assessments
(AMER CHEMICAL SOC, 2024-11-28) Mravcová, Ludmila; Jašek, Vojtěch; Hamplová, Marie; Navrkalová, Jitka; Amrichová, Anna; Zlámalová Gargošová, Helena; Fučík, Jan
The escalating global water scarcity demands innovative solutions, one of which is hydroponic vegetable cultivation systems that increasingly use reclaimed wastewater. Nevertheless, even treated wastewater may still harbor various emerging organic contaminants, including pharmaceuticals. This study aimed to comprehensively assess the impact of pharmaceuticals, focusing on bioconcentration factors (BCFs), translocation factors (TFs), pharmaceutical persistence in aqueous environment, ecotoxicological end points, and associated environmental and health risks. Lettuce (Lactuca sativa) was cultivated hydroponically throughout its entire growth cycle, exposed to seven distinct concentration levels of contaminants ranging from 0 to 500 mu gL-1 over a 35-day period. The findings revealed a diverse range of BCFs (2.3 to 880 Lkg(-1)) and TFs (0.019-1.48), suggesting a high potential of pharmaceutical uptake and translocation by L. sativa. The degradation of 20 pharmaceuticals within the water-lettuce system followed first-order degradation kinetics. Substantial ecotoxicological effects on L. sativa were observed, including increased mortality, alterations in root morphology and length, and changes in biomass weight (p < 0.05). Furthermore, the estimated daily intake of pharmaceuticals through L. sativa consumption suggested considerable health risks, even if lettuce would be one of the many vegetables consumed. It is hypothetical, as the values were calculated. Moreover, this study assessed the environmental risk associated with the emergence of antimicrobial resistance (AMR) in aquatic environments, revealing a significantly high risk of AMR emergence. In conclusion, these findings emphasize the multifaceted challenges posed by pharmaceutical contamination in aquatic environments and the necessity of proactive measures to mitigate associated risks to both environmental and human health.
Naphthalene-stilbenes as effective visible-light sensitizers to study the effect of diluent and nanofillers on in situ photopolymerization and 3D-VAT printing process
(ROYAL SOC CHEMISTRY, 2024-01-23) Tomal, Wiktoria; Galuszka, Karolina; Lepcio, Petr; Pilch, Maciej; Chachaj-Brekiesz, Anna; Korčušková, Martina; Ortyl, Joanna
This study presents novel photoinitiating systems based on diaryliodonium salt (IOD) and 1-amino-4-methyl-6-styrylnaphthalene-2-carbonitrile derivatives developed as universal IOD photosensitizers. These systems' spectroscopic characteristics, electrochemical behavior, and thermodynamic parameters were investigated to determine the optimal two-component photoinitiating system for light-initiated polymerization, including free-radical and cationic reactions. This versatility in initiating both types of reactions was utilized to explore the dilution effect of non-reactive and two different reactive (cationic, free-radical) diluents. The best formulation was chosen according to Fourier-transform infrared spectroscopy (FTIR), photorheology, thermogravimetric analysis (TGA), and dynamic mechanical analysis (DMA) and tested for the preparation of functional nanocomposites with two types of nanofiller: silver oxide (Ag2O) and hydroxyapatite (HA). The manufacturing process based on additive technology was analyzed according to FTIR spectroscopy and viscosity changes. The results show the high potential of the newly developed photosensitizers in practical applications and 3D-VAT printing.
Graphene quantum dots-From spectroscopic performance to 3D printing applications and interaction studies with normal and cancer cells
(Elsevier, 2024-05-27) Krok-Janiszewska, Dominika; Wielgus, Weronika; Środa, Patrycja; Tyszka-Czochara, Małgorzata; Lepcio, Petr; Kasprzyk, Wiktor; Ortyl, Joanna
In this study, different types of graphene quantum dots (GQDs) are investigated to understand their spectroscopic properties. Morphological and size analyses were performed. The mechanism of action of radical photopolymerization was evaluated. The obtained materials proved to be useful for developing efficient photoinitiating systems for 3D printing applications. In addition, the cytotoxicity of the GQDs was studied, and their effects on living cells were investigated. We demonstrated that GQDs can not only act as efficient photoinitiators but also as constituents of hydrogels that express very low toxicity and may interact with cells. The latter makes it possible to study them in the future as useful modern biosensors.

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