1. Sustained Delivery of Cu (II)-Based DNA Intercalators by Nanometer-sized Cyclodextrin-based Porous PolymersTina Skorjanc, Julian Heinrich, Damjan Makuc, Nora Kulak, Matjaz Valant, 2023, original scientific article Abstract: DNA intercalators are small molecules that insert between adjacent DNA base pairs and thus disturb DNA replication and transcription, which can lead to cell death. Certain metal complexes are excellent DNA intercalators, and have shown promise in chemotherapy. Here, a cyclodextrin porous polymer was prepared, characterized, exfoliated to form nanometer-sized particles, and used as a delivery vehicle for metal-free and Cu(II)-metalated anthraquinone-based DNA intercalators with a goal to minimize side effects of the highly toxic DNA intercalators. NMR experiments, including DOSY NMR, have shown the interaction between the cyclodextrin building block and the studied DNA intercalators. Porous nature of the delivery vehicle provided ample surface area for interaction with the drug candidates, resulting in encapsulation rates of up to 56%. Sustained cargo release from the polymer was achieved over eight days, and time-dependent cytotoxicity was observed. Furthermore, optical microscopy images indicated delivery vehicle internalization as well as disturbed cellular morphology within 24 hours of incubation. We anticipate that this study will stimulate further interest in the development of polymeric delivery systems for metal complexes.
Keywords: Porous organic polymers, cyclodextrin, DNA intercalators, Cu(II) complexes, metal complexes, drug delivery, anthraquinone
Published in RUNG: 10.11.2023; Views: 228; Downloads: 2
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2. In vitro tumor hypoxia imaging with fluorescent covalent organic frameworksTina Skorjanc, Dinesh Shetty, Damjan Makuc, Gregor Mali, Martina Bergant Marušič, Matjaz Valant, 2023, published scientific conference contribution abstract Abstract: Hypoxia refers to a condition where cells and tissues experience low, inadequate levels of O2. While healthy tissues are typically supplied with sufficient O2 (normoxia), cancerous tissues commonly face hypoxia due to the tumor’s extraordinarily high demand for oxygen. Various fluorescent small-molecule probes have been designed for selective detection of hypoxia in living cells, but few nanomaterials have been investigated for this type of bioimaging. Herein, we prepare a fluorescent covalent organic framework (COF) with β-ketoenamine linkages and post-synthetically modify it to conjugate hypoxia-sensitive nitroimidazole moieties
into its pores (NI-COF). Stacks of sheets in NI-COF observed under electron microscopy were exfoliated by ultrasonication, and dynamic light scattering measurements confirmed particle size of less than 200 nm. Thus-prepared material exhibited good stability in physiological conditions and low cytotoxicity in in vitro experiments. NI-COF also showed useful fluorescence properties with an emission peak at 490 nm (λex = 420 nm) at both neutral and mildly acidic pH levels that are characteristic of tumor tissues. Encouraged by the favorable properties of the material, we incubated HeLa cells pre-treated in either hypoxic or normoxic conditions with NI-COF. Fluorescence microscopy images demonstrated that the material was preferentially taken up by hypoxic cells, which showed higher fluorescence signal in their interior than cells cultured under normoxia conditions. It is anticipated that this study will stimulate further developments of COFs for imaging various biological conditions.
Keywords: hypoxia, fluorescence, covalent organic frameworks, imaging, tumor cells
Published in RUNG: 19.09.2023; Views: 348; Downloads: 3
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3. Self-adaptive amorphous CoOxCly electrocatalyst for sustainable chlorine evolution in acidic brineMengjun Xiao, Qienbao Wu, Ruiqi Ku, Liujiang Zhou, Chang Long, Junwu Liang, Andraž Mavrič, Lei Li, Jing Zhu, Matjaz Valant, Jiong Li, Zhenhua Zheng, Chunhua Cui, 2023, original scientific article Abstract: Electrochemical chlorine evolution reaction is of central importance in the chlor-alkali industry, but the chlorine evolution anode is largely limited by water oxidation side reaction and corrosion-induced performance decay in strong acids. Here we present an amorphous CoOxCly catalyst that has been deposited in situ in an acidic saline electrolyte containing Co2+ and Cl- ions to adapt to the given electrochemical condition and exhibits ~100% chlorine evolution selectivity with an overpotential of ~0.1 V at 10 mA cm−2 and high stability over 500 h. In situ spectroscopic studies and theoretical calculations reveal that the electrochemical introduction of Cl- prevents the Co sites from charging to a higher oxidation state thus suppressing the O-O bond formation for oxygen evolution. Consequently, the chlorine evolution selectivity has been enhanced on the Cl-constrained Co-O* sites via the Volmer-Heyrovsky pathway. This study provides fundamental insights into how the reactant Cl-itself can work as a promoter toward enhancing chlorine evolution in acidic brine.
Keywords: Catalyst synthesis, Electrocatalysis, Chlorine evolution
Published in RUNG: 04.09.2023; Views: 367; Downloads: 3
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4. Covalent organic frameworks for fluorescent imaging of hypoxiaTina Skorjanc, Dinesh Shetty, Gregor Mali, Damjan Makuc, Martina Bergan Marušič, Matjaz Valant, 2023, published scientific conference contribution abstract Keywords: hypoxia, covalent organic frameworks, imaging, fluorescence, post-synthetic modification
Published in RUNG: 06.06.2023; Views: 645; Downloads: 0
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5. Nitroreductase-sensitive fluorescent covalent organic framework for tumor hypoxia imaging in cellsTina Skorjanc, Dinesh Shetty, Sushil Kumar, Damjan Makuc, Gregor Mali, Janez Vovavšek, Martina Bergant Marušič, Matjaz Valant, 2023, original scientific article Keywords: covalent organic frameworks, imaging, hypoxia, fluorescence, cancer cells
Published in RUNG: 17.05.2023; Views: 662; Downloads: 6
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6. Stable seawater oxidation with a self-healing oxygen-evolving catalystXiaojian Zhang, Chao Feng, Zeyu Fan, Beibei Zhang, Yequan Xiao, Andraž Mavrič, Nadiia Pastukhova, Matjaz Valant, Yi-Fan Han, Yanbo Li, 2023, original scientific article Abstract: Direct seawater electrolysis is key to massive hydrogen fuel production without the depletion of precious freshwater resources and the need for high-purity electrolytes. However, the presence of high-concentration chloride ions (Cl−) and alkaline-earth metal ions (Mg2+, Ca2+) poses great challenges to the stability and selectivity of the catalysts for seawater splitting. Here, we demonstrate a self-healing oxygen evolution reaction (OER) catalyst for long-term seawater electrolysis. By suppressing the competitive chlorine evolution reaction and precipitating the alkaline-earth metal ions through an alkaline treatment of the seawater, stable seawater oxidation is achieved owing to the self-healing ability of the borate-intercalated nickel–cobalt–iron oxyhydroxides (NiCoFe-Bi) OER catalyst under highly-alkaline conditions. The self-healing NiCoFe-Bi catalyst achieves stable seawater oxidation at a large current density of 500 mA cm−2 for 1000 h with near unity Faraday efficiency. Our results have demonstrated strong durability and high OER selectivity of the self-healing catalyst under harsh conditions, paving the way for industrial large-scale seawater electrolysis.
Keywords: chemistry, electrocatalysis, seawater oxidation, oxygen evolution reaction
Published in RUNG: 08.05.2023; Views: 639; Downloads: 0
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7. Life Cycle Assessment of Black and Greywater Treatment Solutions for Remote and Sensitive AreasOarga-Mulec Andreea, Turk Janez, Gerbec Petra, Jenssen Peter D., Malovrh Rebec Katja, Valant Matjaz, 2023, original scientific article Keywords: life cycle assessment, sanitation systems, sustainability, remote areas, circular economy
Published in RUNG: 20.02.2023; Views: 905; Downloads: 0
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8. Iron phosphide thin films for electrocatalytic H2 generation and water remediation studies : abstractTakwa Chouki, Manel Machreki, Jelena Topic, Lorena Butinar, Plamen Stefanov, Erika Jez, Jack S Summers, Matjaz Valant, Aaron Fait, Saim Emin, 2022, published scientific conference contribution abstract Keywords: Iron phosphide thin films
H2 generation
water remediation
Published in RUNG: 10.02.2023; Views: 705; Downloads: 0
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9. V-ORAL17c: Cationic Covalent Organic Polymer for Bacterial Cell Detection by Electrochemical Impedance SpectroscopyTina Skorjanc, Andraz Mavric, Mads Nybo Sorensen, Gregor Mali, Changzhu Wu, Matjaz Valant, 2022, published scientific conference contribution Keywords: Electrochemical impedance spectroscopy, polymers, Menshutkin reaction, porphyrin, sensor
Published in RUNG: 30.11.2022; Views: 764; Downloads: 0
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