Seznam abstraktů 2023: POSTEROVÁ SEKCE D

Human exposure to nanoparticles (NP) is linked with potential health risks that depend on physico-chemical characteristics of NP and the exposure route. DNA damage represents one of the mechanisms by which NP toxicity is mediated. Here, we investigated the role of NP generated during welding and machining of nanocomposites in the induction of DNA strand breaks and oxidative damage to DNA. The exposed group consisted of 21 workers involved in either operation in two workshops; the controls included 21 individuals not exposed to any known health risk factor. The exposed subjects were sampled twice: before and after the working shift; exposure to NP was assessed using stationary and personal monitors. The stationary monitoring data showed significant differences in NP generated by both processes, with machining being a dominant source of NP in the working environment. The personal exposure measurements confirmed this trend and revealed large inter-individual variability between the workers. When compared with the controls, nanocomposite workers had significantly increased levels of DNA damage, which was even more apparent when post-shift samples were considered. However, no significant association between any type of DNA damage and personal exposure to NP was found in the exposed group. In summary, the nanocomposite workers are at potentially greater risk of DNA damage-associated health impacts; the process, however, does not seem to be related to the personal exposure to NP. ACKNOWLEDGEMENST: Supported by the Grant Agency of the Czech Republic #22-08358S.

Nanoparticles (NPs) became an important part of everyday life in the last two decades. Among many applications, nanocomposites are frequently used in dentistry. Apart from their undoubted benefits, the questions related to the risk of NPs inhalation during their processing by milling or polishing for human health, and/or the integrity and function of the genome arise. Despite these facts, human biomonitoring studies relevant to this topic are still rare and analyses concerning the cytogenetic effects of NPs exposure during the processing of nanocomposites in stomatology are completely missing.
In this study we analyzed a group of 24 women (age 37±2 years) acutely exposed during dental nanocomposite grinding. All of them were sampled twice: before and after the work. Aerosol exposure monitoring of particulate matter (PM) including nano-sized fractions was performed together with working activities by using stationary and personally monitoring. The whole-chromosome painting (WCP) for autosomes #1 and #4 and gonosome X was applied for estimating the range of cytogenetic damage. The frequencies of both structural chromosomal aberrations as well as numerical alterations were evaluated. Obtained results show differences in genetic alterations related to the type of chromosomal aberrations. While the genomic frequency of translocations remained stable after the short-time acute exposure, the frequency of numerical aberrations significantly differed. Moreover, differences between the alterations of autosomes and gonosome were observed. In conclusion, exposure to NPs is followed by the increase frequency of numerical aberrations which can be dangerous especially for dividing cells. ACKNOWLEDGEMENTS: Supported by the Grant Agency of the Czech Republic #22-08358S and MEYS #LM2023066.

Nanoparticles (NPs) are nowadays commonly used in commercial products including dental nanocomposites to improve material properties. The advantages of commonly used NPs in modern dentistry are extensive, but the effect of their exposure on human health and epigenome is still unknown. In dental practice the dental personnel are mainly exposed to nanoparticle dust. While the NPs in the composites are chemically bonded to the polymer matrix and do not present any adverse effects. The grinding and polishing of nanocomposites during dental treatment produces an aerosol containing high concentration of NPs, that may enter deeply into the lungs. The occupational exposure to inhaled nanoparticles raises questions regarding the risk of human health and genome function. Exposure to NPs may contribute to alterations of gene expression and its regulation. Therefore, more toxicological research on transcriptomic level is needed.
In this project we searched for the possible impact of short-time inhalation exposure to NPs released during grinding dental nanocomposite on transcriptome changes in 24 volunteers to simulate the reality of dentist’s work. Subjects were sampled twice per day, before (pre-shift) and after exposure (post-shift). Total RNA was isolated from collected blood and used for miRNA and mRNA libraries preparation. After sequencing, analyses of the differential mRNA and miRNA expression was performed.
In conclusion, we detected variations of deregulated miRNA and mRNA among studied volunteers. Our results indicate that the impact of exposure to NPs is dependent on the style of working with nanocomposites as well as on the intraindividual biological variability among people. ACKNOWLEDGEMENTS: This work was supported by the Grant Agency of the Czech Republic #22-08358S and MEYS #LM2023066.

In the recent years, the contamination of wastewater by micro- and nanoplastics is turning into a problem, which becomes prominent in wastewater plants, from where the polluted water is released into the environment. A possible concept to avoid this is the microbial remediation of micro- and nanoplastics. For this approach degradable block copolymers were synthesized, which adhere on micro- and nanoplastic surfaces by a hydrophobic anchor group out of PLA. In addition, the block copolymers contain segments of carbohydrate moieties for the attraction of degrading microbes for an accelerated degradation due to enhanced biofilm formation. The insertion of this system in wastewater treatment plants is possible by the amphiphilic character of the block copolymers. In aqueous medium, they are able to form micelles and serve as adjustable component. In previous work the adhesion behavior on several plastic surfaces was determined. The potential for biocompatibility was also proven by incubation tests using Lacticaseibacillus zeae.

Upconverting nanoparticles (UCNPs) represent a novel class of light-emitting materials. The outstanding properties of UCNPs, such as converting lower-energy photons into higher-energy ones, tunable excitation range, sharp emission bands and low background, deep tissue penetration depth of excitation light and low photodamage, make UCNPs a prospective material for various bioapplications, e.g., bioimaging, drug and gene delivery, and photodynamic therapy. However, there are several disadvantages of neat UCNPs limiting their application in biomedicine: particle aggregation in buffers and biological fluids, protein adsorption on the particle surface, and “dark” toxicity, caused by lanthanide and fluoride ion leakage as a result of particle degradation. Thus, the development of surface-modified UCNPs with improved chemical, colloidal stability and antifouling properties is crucial to overcome the above-mentioned disadvantages and use them in different bioapplications. In this work, poly(2,3-dihydroxypropyl methacrylate)-coated UCNPs were prepared via reversible addition-fragmentation transfer (RAFT) miniemulsion polymerization. To achieve this, uniform UCNPs were synthesized and functionalized with hydrophobic penta(propylene glycol)phosphate methacrylate to reduce the ion leakage and increase particle reactivity for polymerization. Then, the poly(2,3-epoxypropyl methacrylate)-coated UCNPs were synthesized via miniemulsion RAFT polymerization. The reactive hydrophobic polymer shell could be used for theranostic agents incorporation, and further be transformed into a hydrophilic shell by hydrolysis. The synthesized surface-modified UCNPs were characterized using DLS, fluorescent emission spectroscopy, TEM and SEM microscopy. The presence of polymer layer on the particle surface was confirmed by FTIR and TGA. Furthermore, the dispersion and chemical stability of synthesized particles, as well as the antifouling properties and cytotoxicity were evaluated. ACKNOWLEDGEMENTS: The support of the National Institute for Cancer Research (Programme EXCELES, No. LX22NPO5102) funded by the European Union, Next Generation EU is acknowledged.