11. Characterizing the sources of ambient ▫$PM_10$▫ organic aerosol in urban and rural Catalonia, SpainMarten in ʼt Veld, Peeyush Khare, Yufang Hao, Cristina Reche, Noemí Perez, Andrés Alastuey, Jesús Yus-Díez, Nicolas Marchand, Andre S. H. Prevot, Xavier Querol, Kaspar Rudolf Daellenbach, 2023, original scientific article Keywords: PM10, chemical composition, organic aerosols, SOA, source apportionment Published in RUNG: 23.10.2023; Views: 843; Downloads: 6 Full text (7,72 MB) This document has many files! More... |
12. In vitro tumor hypoxia imaging with fluorescent covalent organic frameworksTina Skorjanc, Dinesh Shetty, Damjan Makuc, Gregor Mali, Martina Bergant Marušič, Matjaž 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: 835; Downloads: 3 Link to file This document has many files! More... |
13. Functional characterization of Saccharomyces yeasts from cider produced in HardangerUrban Česnik, Mitja Martelanc, Ingunn Ovsthus, Tatjana Radovanović, Ahmad Hosseini, Branka Mozetič Vodopivec, Lorena Butinar, 2023, original scientific article Keywords: Saccharomyces, Hardanger, characterization, fermentation, cider, non-volatile compounds, volatile organic compounds, partial least squares regression Published in RUNG: 18.09.2023; Views: 717; Downloads: 6 Full text (4,79 MB) This document has many files! More... |
14. Enzyme-immobilized hierarchically porous covalent organic framework biocomposite for catalytic degradation of broad-range emerging pollutants in waterNada Elmerhi, Khadega Al-Maqdi, Khawlah Athamneh, Abdul Khayum Mohammed, Tina Škorjanc, Felipe Gándara, Jesus Raya, Pascal Simon, Olivier Siri, Ali Trabolsi, 2023, original scientific article Abstract: Efficient enzyme immobilization is crucial for the successful commercialization of large-scale enzymatic water treatment.
However, issues such as lack of high enzyme loading coupled with enzyme leaching present challenges for the widespread adoption
of immobilized enzyme systems. The present study describes the development and bioremediation application of an enzyme
biocomposite employing a cationic macrocycle-based covalent organic framework (COF) with hierarchical porosity for the
immobilization of horseradish peroxidase (HRP). The intrinsic hierarchical porous features of the azacalix[4]arene-based COF
(ACA-COF) allowed for a maximum HRP loading capacity of 0.76 mg/mg COF with low enzyme leaching (<5.0%). The
biocomposite, HRP@ACA-COF, exhibited exceptional thermal stability (~200% higher relative activity than the free enzyme),
and maintained ~60% enzyme activity after five cycles. LCMSMS analyses confirmed that the HRP@ACA-COF system was able
to achieve >99% degradation of seven diverse types of emerging pollutants (2-mercaptobenzothiazole, paracetamol, caffeic acid,
methylparaben, furosemide, sulfamethoxazole, and salicylic acid)in under an hour. The described enzyme-COF system offers
promise for efficient wastewater bioremediation applications. Keywords: covalent organic frameworks, enzymes, emerging pollutants, water purification, biocomposite Published in RUNG: 11.08.2023; Views: 844; Downloads: 6 Full text (1,45 MB) This document has many files! More... |
15. Changes in exhaled volatile organic compounds following indirect bronchial challenge in suspected asthmaAdam Peel, Ran Wang, Waqar Ahmed, Iain R. White, Maxim Wilkinson, Yoon K. Loke, Andrew M. Wilson, Stephen J. Fowler, 2023, original scientific article Abstract: Background Inhaled mannitol provokes bronchoconstriction via mediators released during osmotic degranulation of inflammatory cells, and, hence represents a useful diagnostic test for asthma and model for acute attacks. We hypothesised that the mannitol challenge would trigger changes in exhaled volatile organic compounds (VOCs), generating both candidate biomarkers and novel insights into their origin.
Methods Participants with a clinical diagnosis of asthma, or undergoing investigation for suspected asthma, were recruited. Inhaled mannitol challenges were performed, followed by a sham challenge after 2 weeks in participants with bronchial hyper-responsiveness (BHR). VOCs were collected before and after challenges and analysed using gas chromatography–mass spectrometry.
Results Forty-six patients (mean (SD) age 52 (16) years) completed a mannitol challenge, of which 16 (35%) were positive, and 15 of these completed a sham challenge. Quantities of 16 of 51 identified VOCs changed following mannitol challenge (p<0.05), of which 11 contributed to a multivariate sparse partial least square discriminative analysis model, with a classification error rate of 13.8%. Five of these 16 VOCs also changed (p<0.05) in quantity following the sham challenge, along with four further VOCs. In patients with BHR to mannitol distinct postchallenge VOC signatures were observed compared with post-sham challenge.
Conclusion Inhalation of mannitol was associated with changes in breath VOCs, and in people with BHR resulted in a distinct exhaled breath profile when compared with a sham challenge. These differentially expressed VOCs are likely associated with acute airway inflammation and/or bronchoconstriction and merit further investigation as potential biomarkers in asthma. Keywords: asthma, exhaled volatile organic compounds, pulmonology, breath metabolomics Published in RUNG: 31.07.2023; Views: 902; Downloads: 3 Link to file |
16. Biological applications of porous polymers and covalent organic frameworks : lecture at the Otto-von-Guericke Universität Magdeburg, Tuesday, 27th June 2023, Magdeburg, GermanyTina Škorjanc, 2023, unpublished conference contribution Abstract: Porous organic polymers (POPs) and covalent organic frameworks (COFs) have gained significant attention in the scientific community for a wide array of applications because of their attractive physical and chemical properties. Porosity of these materials provides ample surface area for interaction with targets, while crystallinity allows for highly specific structural tuning. In this seminar, I will present two strategies of utilizing these features of newly prepared materials in biosensing. Firstly, a cationic POP was synthesized, deposited onto interdigitated electrode arrays via a nontraditional electrophoresis technique, and utilized for electrochemical sensing of bacterial cells. As the principle of detection relied on electrostatic interactions between the cationic POP and the anionic bacterial surface, the sensor operated for both Gram-positive and Gram-negative bacteria. Secondly, a small-molecule nitroimidazole target for hypoxia, a low oxygen environment present in tumors, was post-synthetically conjugated to the pores of a fluorescent COF. This material served as a useful hypoxia imaging agent in cancerous cells. The seminar will conclude with some future perspectives on POPs and COFs in biological applications followed by Q & A. Keywords: Porous organic polymers, covalent organic frameworks, biosensors, hypoxia Published in RUNG: 13.07.2023; Views: 868; Downloads: 0 This document has many files! More... |
17. Modulation of charge transfer exciton dynamics in organic semiconductors using different structural arrangementsCristian Soncini, Abhishek Kumar, Federica Bondino, Elena Magnano, Matija Stupar, Barbara Ressel, Giovanni De Ninno, Antonis Papadopoulos, Efthymis Serpetzoglou, Emmanuel Stratakis, Maddalena Pedio, 2023, original scientific article Abstract: In devices based on organic semiconductors, aggregation and inter-molecular interactions play a key role in affecting the photo-physical and dynamical carrier properties of the material, potentially becoming a limiting factor to achieving high efficiency. As a consequence, a detailed understanding of the interplay between the film molecular structure and the material properties is essential to properly
design devices with optimized performance. Here we demonstrate how different molecular structural arrangements modulate the charge transfer (CT) dynamics in cobalt phthalocyanine (CoPc) thin films. By transient absorption spectroscopy and time-resolved photoemission spectroscopy, we study the influence of different CoPc structures on the dynamical electronic properties, the CoPc intra and inter- molecular de-excitation pathways up to 7 ns. We rationalize the ultrafast formation of triplet states in the CoPc through an electron exchange process between the single-occupied Co3dz2 orbital and p orbitals of the macrocycle, which obviate for an energetically unfavourable spin-flip. We found enhanced CT exciton lifetime in the case of the herringbone structure with respect to the brickwork one, possibly explainable by a more efficient CT exciton delocalization along the stacking axis. Keywords: charge transfer, organic molecules, time resolved spectroscopies Published in RUNG: 30.06.2023; Views: 1076; Downloads: 4 Link to file This document has many files! More... |
18. Defective ▫$TiO_2$▫ nanotube arrays for efficient photoelectrochemical degradation of organic pollutantsManel Machreki, Takwa Chouki, Georgi Tyuliev, Dušan Žigon, Bunsho Ohtani, Alexandre Loukanov, Plamen Stefanov, Saim Emin, 2023, original scientific article Abstract: Oxygen vacancies (OVs) are one of the most critical factors that enhance the electrical and catalytic characteristics of metal oxide-based photo-electrodes. In this work, a simple procedure was applied to prepare reduced TiO 2 nanotube arrays (NTAs) (TiO 2−x) via a one-step reduction method using NaBH 4. A series of characterization techniques were used to study the structural, optical, and electronic properties of TiO 2−x NTAs. X-ray photoelectron spectroscopy confirmed the presence of defects in TiO 2−x NTAs. Photoacoustic measurements were used to estimate the electron-trap density in the NTAs. Photoelectrochemical studies show that the photocurrent density of TiO 2−x NTAs was nearly 3 times higher than that of pristine TiO 2. It was found that increasing OVs in TiO 2 affects the surface recombination centers, enhances electrical conductivity, and improves charge transport. For the first time, a TiO 2−x photoanode was used in the photo-electrochemical (PEC) degradation of a textile dye (basic blue 41, B41) and ibuprofen (IBF) pharmaceutical using in situ generated reactive chlorine species (RCS). Liquid chromatography coupled with mass spectrometry was used to study the mechanisms for the degradation of B41 and IBF. Phytotoxicity tests of B41 and IBF solutions were performed using Lepidium sativum L. to evaluate the potential acute toxicity before and after the PEC treatment. The present work provides efficient PEC degradation of the B41 dye and IBF in the presence of RCS without generating harmful products. Keywords: TiO2, nanotube arrays, photoelectrochemical degradation, organic pollutants Published in RUNG: 12.06.2023; Views: 1025; Downloads: 7 Full text (4,22 MB) This document has many files! More... |
19. Covalent organic frameworks for fluorescent imaging of hypoxiaTina Škorjanc, Dinesh Shetty, Gregor Mali, Damjan Makuc, Martina Bergant Marušič, Matjaž Valant, 2023, published scientific conference contribution abstract Keywords: hypoxia, covalent organic frameworks, imaging, fluorescence, post-synthetic modification Published in RUNG: 06.06.2023; Views: 1079; Downloads: 2 Link to file This document has many files! More... |
20. Nitroreductase-sensitive fluorescent covalent organic framework for tumor hypoxia imaging in cellsTina Škorjanc, Dinesh Shetty, Sushil Kumar, Damjan Makuc, Gregor Mali, Janez Volavšek, Martina Bergant Marušič, Matjaž Valant, 2023, original scientific article Keywords: covalent organic frameworks, imaging, hypoxia, fluorescence, cancer cells Published in RUNG: 17.05.2023; Views: 1098; Downloads: 10 Full text (1,55 MB) This document has many files! More... |