1. Improved adhesion and biocompatibility of chitosan-coated super-hydrophilic PVC polymer substrates for urothelial cathetersAlenka Vesel, Helena Motaln, Miran Mozetič, Dane Lojen, Nina Recek, 2025, izvirni znanstveni članek Povzetek: Chitosan is a water-soluble polysaccharide with good adherence to negatively charged surfaces and reported antimicrobial and anti-inflammatory properties. Coating the surfaces of medical devices with chitosan is a promising strategy for harnessing these benefits. However, the surface properties of commercial polymers need to be altered to enable the bonding of thin chitosan films. In this study, the adhesion of chitosan onto plasma-treated polyvinyl chloride (PVC) and the metabolic activity of urothelial cells on chitosan-coated medical-grade PVC used for the synthesis of urinary catheters were evaluated. To improve the adhesion of chitosan onto the PVC catheters, PVC samples were made “super-hydrophilic”. PVC substrates were briefly treated with a powerful hydrogen plasma and weakly ionised oxygen plasma afterglow to obtain a chlorine-free surface film, which was rich in oxygen functional groups, followed by incubation of the plasma-treated substrates in an aqueous solution of chitosan. Then, urothelial RT4 cells were seeded on the treated and untreated PVC substrates, and their metabolic activity, confluency, and cell morphology were examined. X-ray photoelectron spectroscopy was used to measure the nitrogen concentration, which corresponded to the chitosan concentration on the substrate. The results showed that the substrates were uniformly covered by a thin layer of chitosan only on plasma-treated surfaces and not on untreated surfaces. Moreover, the chitosan coating provided a stimulated environment for cell adhesion and growth. In conclusion, the chitosan-coated super-hydrophilic PVC substrate shows potential to improve the overall performance and safety of medical devices such as urinary catheters.
Ključne besede: medical-grade PVC, chitosan coating, urinary catheter, urothelial cells, cytotoxicity, adhesion, biocompatibility
Objavljeno v DiRROS: 28.02.2025; Ogledov: 246; Prenosov: 140
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2. Cytotoxicity assessment of HDPE microplastic on Tetrahymena thermophila (Protozoa, Ciliate) : assuring quality and FAIR dataValentina Perc, Veno Kononenko, Nina Jeliaskova, Matej Hočevar, Slavko Kralj, Darko Makovec, Maja Caf, Damjana Drobne, Sara Novak, 2024, izvirni znanstveni članek Ključne besede: cytotoxicity, microplastic, HDPE, FAIR data, tetrahymena thermophila
Objavljeno v DiRROS: 16.12.2024; Ogledov: 425; Prenosov: 193
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3. Synthesis, purification, and cell-toxicity of a choline betainateLucija Jurko, Gregor Hostnik, Tobias Alexander Steindorfer, Alja Štern, Perica Bošković, Matej Bračič, Bojana Žegura, Rupert Kargl, 2024, izvirni znanstveni članek Povzetek: In this work, choline chloride and betaine hydrochloride were condensed into a - to our knowledge - unreported choline betainate (N,N,N-trimethyl-2-oxo-2-(2-(trimethylammonio)ethoxy)ethanaminium chloride) using 1,1′-carbonyldiimidazole (CDI) activation of betaine hydrochloride in dimethylsulfoxide. The product and reaction intermediates were isolated, purified by preparative HPLC and analyzed in detail by infrared and nuclear magnetic resonance spectroscopy. The final product has a high cytotoxicity for L929 mouse fibroblasts, and low antibacterial activity against P. Aeruginosa and S. Aureus at concentrations of up to 20 mg/ml. It could potentially further be investigated for similar uses as suxamethonium chloride, a muscle relaxant drug.
Ključne besede: choline chloride, betaine hydrochloride, carbonyldiimidazole, HPLC, antimicrobial, cytotoxicity
Objavljeno v DiRROS: 07.08.2024; Ogledov: 636; Prenosov: 493
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4. Effect of poly-[alpha], [gamma], L-glutamic acid as a capping agent on morphology and oxidative stress-dependent toxicity of silver nanoparticlesMagdalena Stevanović, Branimir Kovačević, Jana Nunić, Metka Filipič, Dragan Uskoković, 2011, izvirni znanstveni članek Povzetek: Highly stable dispersions of nanosized silver particles were synthesized using a straightforward, cost-effective, and ecofriendly method. Nontoxic glucose was utilized as a reducing agent and poly- α, γ, L-glutamic acid (PGA), a naturally occurring anionic polymer, was used as a capping agent to protect the silver nanoparticles from agglomeration and render them biocompatible. Use of ammonia during synthesis was avoided. Our study clearly demonstrates how the concentration of the capping agent plays a major role in determining the dimensions, morphology, and stability, as well as toxicity of a silver colloidal solution. Hence, proper optimization is necessary to develop silver colloids of narrow size distribution. The samples were characterized by Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, field-emission scanning electron microscopy, transmission electron microscopy, and zeta potential measurement. MTT assay results indicated good biocompatibility of the PGA-capped silver nanoparticles. Formation of intracellular reactive oxygen species was measured spectrophotometrically using 2,7-dichlorofluorescein diacetate as a fluorescent probe, and it was shown that the PGA-capped silver nanoparticles did not induce intracellular formation of reactive oxygen species.
Ključne besede: green synthesis, morphology, cytotoxicity
Objavljeno v DiRROS: 05.08.2024; Ogledov: 591; Prenosov: 328
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5. Plastics in cyanobacterial blooms - genotoxic effects of binary mixtures of cylindrospermopsin and bisphenols in HepG2 cellsKlara Hercog, Alja Štern, Sara Maisanaba Hernández, Metka Filipič, Bojana Žegura, 2020, izvirni znanstveni članek Povzetek: Ever-expanding environmental pollution is causing a rise in cyanobacterial blooms and the accumulation of plastics in water bodies. Consequently, exposure to mixtures of cyanotoxins and plastic-related contaminants such as bisphenols (BPs) is of increasing concern. The present study describes genotoxic effects induced by co-exposure to one of the emerging cyanotoxins—cylindrospermopsin (CYN)—(0.5 µg/mL) and BPs (bisphenol A (BPA), S (BPS), and F (BPF); (10 µg/mL)) in HepG2 cells after 24 and 72 h of exposure. The cytotoxicity was evaluated with an MTS assay and genotoxicity was assessed through the measurement of the induction of DNA double strand breaks (DSB) with the γH2AX assay. The deregulation of selected genes (xenobiotic metabolic enzyme genes, DNA damage, and oxidative response genes) was assessed using qPCR. The results showed a moderate reduction of cell viability and induction of DSBs after 72 h of exposure to the CYN/BPs mixtures and CYN alone. None of the BPs alone reduced cell viability or induced DSBs. No significant difference was observed between CYN and CYN/BPs exposed cells, except with CYN/BPA, where the antagonistic activity of BPA against CYN was indicated. The deregulation of some of the tested genes (CYP1A1, CDKN1A, GADD45A, and GCLC) was more pronounced after exposure to the CYN/BPs mixtures compared to single compounds, suggesting additive or synergistic action. The present study confirms the importance of co-exposure studies, as our results show pollutant mixtures to induce effects different from those confirmed for single compounds.
Ključne besede: cylindrospermopsin, CYN, bisphenols, BPA, BPS, BPF, BPAF, co-exposure, genotoxicity, cytotoxicity
Objavljeno v DiRROS: 23.07.2024; Ogledov: 626; Prenosov: 398
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6. Succinylation of polyallylamine: influence on biological efficacy and the formation of electrospun fibersLucija Jurko, Matej Bračič, Silvo Hribernik, Damjan Makuc, Janez Plavec, Filip Jerenec, Sonja Žabkar, Nenad Gubeljak, Alja Štern, Rupert Kargl, 2021, izvirni znanstveni članek Povzetek: Succinylation of proteins is a commonly encountered reaction in biology and introduces negatively charged carboxylates on previously basic primary amine groups of amino acid residues. In analogy, this work investigates the succinylation of primary amines of the synthetic polyelectrolyte polyallylamine (PAA). It investigates the influence of the degree of succinylation on the cytotoxicity and antibacterial activity of the resulting polymers. Succinylation was performed in water with varying amounts of succinic anhydride and at different pH values. The PAA derivatives were analyzed in detail with respect to molecular structure using nuclear magnetic resonance and infrared absorbance spectroscopy. Polyelectrolyte and potentiometric charge titrations were used to elucidate charge ratios between primary amines and carboxylates in the polymers. The obtained materials were then evaluated with respect to their minimum inhibitory concentration against Staphylococcus aureus and Pseudomonas aeruginosa. The biocompatibility was assessed using mouse L929 fibroblasts. The degree of succinylation decreased cytotoxicity but more significantly reduced antibacterial efficacy, demonstrating the sensitivity of the fibroblast cells against this type of ampholytic polyelectrolytes. The obtained polymers were finally electrospun into microfiber webs in combination with neutral water-soluble polyvinyl alcohol. The resulting non-woven could have the potential to be used as wound dressing materials or coatings.
Ključne besede: polyallylamine hydrochloride, succinylation, aqueous chemistry, cytotoxicity, antimicrobial effect, electrospinning, nanofibers, mouse L929 fibroblasts, Staphylococcus aureus, Pseudomonas aeruginosa
Objavljeno v DiRROS: 19.07.2024; Ogledov: 581; Prenosov: 550
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7. Cytotoxic and genotoxic effects of cyanobacterial and algal extracts-microcystin and retinoic acid contentMichal Bittner, Alja Štern, Marie Smutna, Klara Hilscherova, Bojana Žegura, 2021, izvirni znanstveni članek Povzetek: In the last decade, it has become evident that complex mixtures of cyanobacterial bioactive substances, simultaneously present in blooms, often exert adverse effects that are different from those of pure cyanotoxins, and awareness has been raised on the importance of studying complex mixtures and chemical interactions. We aimed to investigate cytotoxic and genotoxic effects of complex extracts from laboratory cultures of cyanobacterial species from different orders (Cylindrospermopsis raciborskii, Aphanizomenon gracile, Microcystis aeruginosa, M. viridis, M. ichtyoblabe, Planktothrix agardhii, Limnothrix redekei) and algae (Desmodesmus quadricauda), and examine possible relationships between the observed effects and toxin and retinoic acid (RA) content in the extracts. The cytotoxic and genotoxic effects of the extracts were studied in the human hepatocellular carcinoma HepG2 cell line, using the MTT assay, and the comet and cytokinesis-block micronucleus (cytome) assays, respectively. Liquid chromatography electrospray ionization mass spectrometry (LC/ESI-MS) was used to detect toxins (microcystins (MC-LR, MC-RR, MC-YR) and cylindrospermopsin) and RAs (ATRA and 9cis-RA) in the extracts. Six out of eight extracts were cytotoxic (0.04–2 mgDM/mL), and five induced DNA strand breaks at non-cytotoxic concentrations (0.2–2 mgDM/mL). The extracts with genotoxic activity also had the highest content of RAs and there was a linear association between RA content and genotoxicity, indicating their possible involvement; however further research is needed to identify and confirm the compounds involved and to elucidate possible genotoxic effects of RAs.
Ključne besede: cyanobacteria, algae, extracts, complex mixtures, genotoxicity, cytotoxicity, retinoic acids, microcystins, cyanotoxins, chemical analysis
Objavljeno v DiRROS: 19.07.2024; Ogledov: 577; Prenosov: 375
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8. Do cytotoxicity and cell death cause false positive results in the in vitro comet assay?Amaya Azqueta, Helga Stopper, Bojana Žegura, Maria Dusinska, Peter Møller, 2022, izvirni znanstveni članek Povzetek: The comet assay is used to measure DNA damage induced by chemical and physical agents. High concentrations of test agents may cause cytotoxicity or cell death, which may give rise to false positive results in the comet assay. Systematic studies on genotoxins and cytotoxins (i.e. non-genotoxic poisons) have attempted to establish a threshold of cytotoxicity or cell death by which DNA damage results measured by the comet assay could be regarded as a false positive result. Thresholds of cytotoxicity/cell death range from 20% to 50% in various publications. Curiously, a survey of the latest literature on comet assay results from cell culture studies suggests that one-third of publications did not assess cytotoxicity or cell death. We recommend that it should be mandatory to include results from at least one type of assay on cytotoxicity, cell death or cell proliferation in publications on comet assay results. A combination of cytotoxicity (or cell death) and proliferation (or colony forming efficiency assay) is preferable in actively proliferating cells because it covers more mechanisms of action. Applying a general threshold of cytotoxicity/cell death to all types of agents may not be applicable; however, 25% compared to the concurrent negative control seems to be a good starting value to avoid false positive comet assay results. Further research is needed to establish a threshold value to distinguish between true and potentially false positive genotoxic effects detected by the comet assay.
Ključne besede: comet assay, cytotoxicity, genotoxicity, DNA damage, cell death
Objavljeno v DiRROS: 17.07.2024; Ogledov: 636; Prenosov: 411
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9. Adverse toxic effects of tyrosine kinase inhibitors on non-target zebrafish liver (ZFL) cellsKatja Kološa, Bojana Žegura, Martina Štampar, Metka Filipič, Matjaž Novak, 2023, izvirni znanstveni članek Ključne besede: zebrafish liver cells, ZFL, tyrosine kinase inhibitors, cytotoxicity, cell cycle, genotoxicity, environmental hazard
Objavljeno v DiRROS: 12.07.2024; Ogledov: 972; Prenosov: 409
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10. Influence of alkylthio and arylthio derivatives of tert-butylquinone on the induction of DNA damage in a human hepatocellular carcinoma cell line (HepG2)Jelena Djordjević, Stoimir Kolarević, Jovana Jovanović Marić, Margareta Kračun-Kolarević, Bojana Žegura, Alja Štern, Dušan M. Sladić, Irena Novaković, Branka Vuković-Gačić, 2024, izvirni znanstveni članek Povzetek: The aim of this study was to investigate the effects of tert-butylquinone (TBQ) and its alkylthio and arylthio
derivatives on DNA in vitro, using acellular and cellular test systems. Direct interaction with DNA was studied
using the plasmid pUC19. Cytotoxic (MTS assay) and genotoxic (comet assay and γH2AX focus assays) effects,
and their influence on the cell cycle were studied in the HepG2 cell line. Our results show that TBQ and its
derivatives did not directly interact with DNA. The strongest cytotoxic effect on the HepG2 cells was observed for
the derivative 2-tert-butyl-5,6-(ethylenedithio)-1,4-benzoquinone (IC50 64.68 and 55.64 μM at 24-h and 48-h
treatment, respectively). The tested derivatives did not significantly influence the cell cycle distribution in the
exposed cellular populations. However, all derivatives showed a genotoxic activity stronger than that of TBQ in
the comet assay, with 2-tert-butyl-5,6-(ethylenedithio)-1,4-benzoquinone producing the strongest effect. The
same derivative also induced DNA double-strand breaks in the γH2AX focus assay.
Ključne besede: TBQ derivatives, HepG2 cell line, comet assay, γH2AX assay, cell cycle analysis, cytotoxicity
Objavljeno v DiRROS: 11.07.2024; Ogledov: 697; Prenosov: 407
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