| 1. |
- Kaur, Amanpreet, et al.
(författare)
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Chemoselective bicyclobutane-based mass spectrometric detection of biological thiols uncovers human and bacterial metabolites
- 2023
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Ingår i: Chemical Science. - : Royal Society of Chemistry. - 2041-6520 .- 2041-6539. ; 14:20, s. 5291-5301
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Tidskriftsartikel (refereegranskat)abstract
- Sulfur is an essential element of life. Thiol-containing metabolites in all organisms are involved in the regulation of diverse biological processes. Especially, the microbiome produces bioactive metabolites or biological intermediates of this compound class. The analysis of thiol-containing metabolites is challenging due to the lack of specific tools, making these compounds difficult to investigate selectively. We have now developed a new methodology comprising bicyclobutane for chemoselective and irreversible capturing of this metabolite class. We utilized this new chemical biology tool immobilized onto magnetic beads for the investigation of human plasma, fecal samples, and bacterial cultures. Our mass spectrometric investigation detected a broad range of human, dietary and bacterial thiol-containing metabolites and we even captured the reactive sulfur species cysteine persulfide in both fecal and bacterial samples. The described comprehensive methodology represents a new mass spectrometric strategy for the discovery of bioactive thiol-containing metabolites in humans and the microbiome.
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| 2. |
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Cover Feature : Analysis of Anion Binding Effects on the Sensitized Luminescence of Macrocyclic Europium(III) Complexes (Anal. Sens. 6/2022)
- 2022
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Ingår i: Analysis & Sensing. - : John Wiley & Sons. - 2629-2742 .- 2629-2742.
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Konstnärligt arbete (refereegranskat)abstract
- The cover feature image represents the differences in the luminescence response upon fluoride vs cyanide binding to a 1,4,7-triazacyclonane-based Eu(III) complex equipped with a carbostyril light-harvesting antenna. The addition of excess of fluoride boosts the Eu(III) emission quantum yield by up to 6-fold for such compounds. Cyanide addition extinguishes Eu(III) luminescence despite partial anion binding to a lanthanide 3+ ion. These compounds showed opposite responses upon fluoride and cyanide binding, and the results could facilitate the design of responsive probes for multiple anion types. More information can be found in the Research Article (https://doi.org/10.1002/anse.202200015) by K. E. Borbas and co-workers.
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| 3. |
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| 4. |
- Daniel, Quentin
(författare)
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Water oxidation : From Molecular Systems to Functional Devices
- 2017
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Konstnärligt arbete (övrigt vetenskapligt/konstnärligt)abstract
- The production of hydrogen gas, through the process of water splitting,is one of the most promising concepts for the production of clean andrenewable fuel.The introduction of this thesis provides a brief overview of fossil fuelsand the need for an energy transition towards clean and renewable energy.Hydrogen gas is presented as a possible candidate fuel with its productionthrough artificial photosynthesis, being described. However, the highlykinetically demanding key reaction of the process – the water oxidationreaction – requires the use of a catalyst. Hence, a short presentation of differentmolecular water oxidation catalysts previously synthesized is also provided.The second part of the thesis focuses on ruthenium-based molecularcatalysis for water oxidation. Firstly, the design and the catalytic performancefor a new series of catalysts are presented. Secondly, a further study onelectron paramagnetic resonance of a catalyst shows the coordination of awater molecule to a ruthenium centre to generate a 7-coordinated complex atRuIII state. Finally, in an electrochemical study, coupled with nuclear magneticresonance analysis, mass spectrometry and X-ray diffraction spectroscopy, wedemonstrate the ability of a complex to perform an in situ dimerization of twounits in order to generate an active catalyst.The final part of this thesis focuses on immobilisation of first rowtransition metal catalysts on the surface of electrodes for electrochemical wateroxidation. Initially, a copper complex was designed and anchored on a goldsurface electrode. Water oxidation performance was studied byelectrochemistry, while deactivation of the electrode was investigated throughX-ray photoelectron spectroscopy, revealing the loss of the copper complexfrom the electrode during the reaction. Finally, we re-investigated cobaltporphyrin complexes on the surface of the electrode. Against the backgroundof previous report, we show that the decomposition of cobalt porphyrin intocobalt oxide adsorbed on the surface is responsible for the catalytic activity.This result is discussed with regard to the detection limit of various spectroscopic methods.
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| 5. |
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| 6. |
- Karimpour, Masoumeh, 1986-
(författare)
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Multi-platform metabolomics assays to study the responsiveness of the human plasma and lung lavage metabolome
- 2016
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Konstnärligt arbete (övrigt vetenskapligt/konstnärligt)abstract
- Metabolomics as a field has been used to track changes and perturbations in the human body by investigating metabolite profiles indicating the change of metabolite levels over time and in response to different challenges. In this thesis work, the main focus was on applying multiplatform-metabolomics to study the human metabolome following exposure to perturbations, such as diet (in the form of a challenge meal) and exhaust emissions (air pollution exposure in a controlled setting). The cutting-edge analytical platforms used for this purpose were nuclear magnetic resonance (NMR), as well as gas chromatography (GC) and liquid chromatography (LC) coupled to mass spectrometry (MS). Each platform offered unique characterization features, allowing detection and identification of a specific range of metabolites. The use of multiplatform-metabolomics was found to enhance the metabolome coverage and to provide complementary findings that enabled a better understanding of the biochemical processes reflected by the metabolite profiles. Using non-targeted analysis, a wide range of unknown metabolites in plasma were identified during the postprandial stage after a well-defined challenge meal (in Paper I). In addition, a considerable number of metabolites were detected and identified in lung lavage fluid after biodiesel exhaust exposure compared to filtered air exposure (in Paper II). In parallel, using targeted analysis, both lung lavage and plasma fatty acid metabolites were detected and quantified in response to filtered air and biodiesel exhaust exposure (in Paper III and IV).Data processing of raw data followed by data analysis, using both univariate and multivariate methods, enabled changes occurring in metabolites levels to be screened and investigated. For the initial pilot postprandial study, the aim was to investigate the plasma metabolome response after a well-defined meal during the postprandial stage for two types of diet. It was found that independent of the background diet type, levels of metabolites returned to their baseline levels after three hours. This finding was taken into consideration for the biodiesel exhaust exposures studies, designed to limit the impact of dietary effects. Both targeted and non-targeted approaches resulted in important findings. For instance, different metabolite profiles were detected in bronchial wash (BW) compared to bronchoalveolar lavage (BAL) fluid with mainly NMR and LC-MS. Furthermore, biodiesel exhaust exposure resulted in different metabolite profiles as observed by GC-MS, especially in BAL. In addition, fatty acid metabolites in BW, BAL, and plasma were shown to be responsive to biodiesel exhaust exposure, as measured by a targeted LC-MS/MS protocol. In summary, the new analytical methods developed to investigate the responsiveness of the human plasma and lung lavage metabolome proved to be useful in an analytical perspective, and provided important biological findings. However, further studies are needed to validate these results.
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| 7. |
- Khaliliazar, Shirin, et al.
(författare)
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Woven Electroanalytical Biosensor for Nucleic AcidAmplification Tests
- 2021
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Ingår i: Advanced Healthcare Materials. - : Wiley-VCH Verlagsgesellschaft. - 2192-2640 .- 2192-2659. ; 10:11, s. 2100034-
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Tidskriftsartikel (refereegranskat)abstract
- Fiber-based biosensors enable a new approach in analytical diagnosticdevices. The majority of textile-based biosensors, however, rely oncolorimetric detection. Here a woven biosensor that integrates microfluidicsstructures in combination with an electroanalytical readout based on athiol-self-assembled monolayer (SAM) for Nucleic Acid Amplification Testing,NAATs is shown. Two types of fiber-based electrodes are systematicallycharacterized: pure gold microwires (bond wire) and off-the-shelf plasmagold-coated polyester multifilament threads to evaluate their potential to formSAMs on their surface and their electrochemical performance in woven textile.A woven electrochemical DNA (E-DNA) sensor using a SAM-based stem-loopprobe-modified gold microwire is fabricated. These sensors can specificallydetect unpurified, isothermally amplified genomic DNA of Staphylococcusepidermidis (10 copies/μL) by recombinase polymerase amplification (RPA).This work demonstrates that textile-based biosensors have the potential forintegrating and being employed as automated, sample-to-answer analyticaldevices for point-of-care (POC) diagnostics.
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| 8. |
- Meng, Lingyin, 1991-
(författare)
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Tailoring Conducting Polymer Interface for Sensing and Biosensing
- 2020
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Konstnärligt arbete (övrigt vetenskapligt/konstnärligt)abstract
- The routine measurement of significant physiological and biochemical parameters has become increasingly important for health monitoring especially in the cases of elderly people, infants, patients with chronic diseases, athletes and soldiers etc. Monitoring is used to assess both physical fitness level and for disease diagnosis and treatment. Considerable attention has been paid to electrochemical sensors and biosensors as point-of-care diagnostic devices for healthcare management because of their fast response, low-cost, high specificity and ease of operation. The analytical performance of such devices is significantly driven by the high-quality sensing interface, involving signal transduction at the transducer interface and efficient coupling of biomolecules at the transducer bio-interface for specific analyte recognition. The discovery of functional and structured materials, such as metallic and carbon nanomaterials (e.g. gold and graphene), has facilitated the construction of high-performance transducer interfaces which benefit from their unique physicochemical properties. Further exploration of advanced materials remains highly attractive to achieve well-designed and tailored interfaces for electrochemical sensing and biosensing driven by the emerging needs and demands of the “Internet of Things” and wearable sensors.Conducting polymers (CPs) are emerging functional polymers with extraordinary redox reversibility, electronic/ionic conductivity and mechanical properties, and show considerable potential as a transducer material in sensing and biosensing. While the intrinsic electrocatalytic property of the CPs is limited, especially for the bulk polymer, tailoring of CPs with controlled structure and efficient dopants could improve the electrochemical performance of a transducer interface by delivering a larger surface area and enhanced electrocatalytic property. In addition, the rich synthetic chemistry of CPs endows them with versatile functional groups to modulate the interfacial properties of the polymer for effective biomolecule coupling, thus bridging organic electronics and bioelectrochemistry. Moreover, the soft-material characteristics of CPs enable their use for the development of flexible and wearable sensing platforms which are inexpensive and light-weight, compared to conventional rigid materials, such as carbons, metals and semiconductors.This thesis focuses on the exploration of CPs for electrochemical sensing and biosensing with improved sensitivity, selectivity and stability by tailoring CP interfaces at different levels, including the CP-based transduction interface, CP-based bio-interface and CP-based device interface.First, we demonstrate different strategies for tailoring the physicochemical properties of poly (3,4-ethylenedioxythiophene) (PEDOT) beyond its intrinsic properties, via charge effects, structural effects and by the use of hybrid materials, as a CP-based transduction interface to improve sensing performance of various analytes. 1) A positively-charged PEDOT interface, and a negatively-charged carboxylic-acid-functionalised PEDOT (PEDOT:COOH) interface were developed to modulate the electrode kinetics for oppositely-charged analytes, e.g. negatively-charged nicotinamide adenine dinucleotide (NADH) and positively-charged dopamine (DA), respectively. These interfaces displayed high sensitivity and wide linear range towards the analytes due to the electrostatic attraction effect. 2) Various structured PEDOT including porous microspheres and nanofibres were synthesised via hard-template and soft-template methods, respectively, and were employed as building blocks for a hierarchical PEDOT and 3D nanofibrous PEDOT transduction interface, that facilitated signal transduction for NADH. 3) A PEDOT hybrid material interface was developed via using a novel bi-functional graphene oxide derivative with high reduction degree and negatively-charged sulphonate terminal functionality (S-RGO) as dopant to create PEDOT:S-RGO which delivered an enhanced electrochemical performance for various analytes.Based on the established CP-based transduction interface, biomolecules (e.g. enzymes) could be coupled to the CP surface to create CP-based bio-interfaces for biosensing. The immobilisation of enzyme was realised via either covalent bonding to a PEDOT derivative bearing a -COOH group (PEDOT-COOH) through EDC/NHS chemistry, or by physical absorption into the 3D porous PEDOT structure. The CP-based bio-interfaces were used to demonstrate the stable immobilisation of two different types of enzymes, i.e. lactate dehydrogenase and lactate oxidase, achieving the biosensing of analytes by relay bioelectrochemical signal transduction.Together, CP was employed as the CP-based device interface for the fabrication of a flexible and wearable biosensing device. A 3D honeycomb-structured graphene network was generated in-situ on a flexible polyimide surface by mask-free patterning using laser irradiation. The substrate was then reinforced with PEDOT as a polymeric binder to stabilise the 3D porous network by adhesion and binding, thus minimising the delamination of the biosensing interface under deformation and enhancing the mechanical behaviours for use in flexible and wearable devices. The subsequent nanoscale-coating of Prussian blue and immobilisation of enzyme into the 3D porous network provided a flexible platform for wearable electrochemical biosensors to detect lactate in sweat.
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| 9. |
- Pati, Palas Baran, et al.
(författare)
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Insights into the Mechanism of a Covalently Linked Organic Dye-Cobaloxime Catalyst System for Dye-Sensitized Solar Fuel Devices
- 2017
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Ingår i: ChemSusChem. - : Wiley. - 1864-5631 .- 1864-564X. ; 10:11, s. 2480-2495
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Tidskriftsartikel (refereegranskat)abstract
- A covalently-linked organic dye-cobaloxime catalyst system is developed by facile click reaction for mechanistic studies and application in a dye sensitized solar fuel device based on mesoporous NiO. This system has been systematically investigated by photophysical measurements, density functional theory, time resolved fluorescence, transient absorption spectroscopy as well as photoelectron spectroscopy. The results show that irradiation of the dye-catalyst on NiO leads to ultrafast hole injection into NiO from the excited dye, followed by a fast electron transfer to reduce the catalyst unit. Moreover, they suggest that the dye undergoes structural changes in the excited state and that excitation energy transfer occurs between neighboring molecules. The photoelectrochemical experiments also show the hydrogen production by this system-based NiO photocathode. The axial chloride ligands of the catalyst are released during photocatalysis to create the active sites for proton reduction. A working mechanism of the dye-catalyst on photocathode is eventually proposed on the basis of this study.
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| 10. |
- Wang, Xuying, et al.
(författare)
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Analytical survey of tattoo inks – a chemical and legal perspective with focus on sensitizing substances
- 2021
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Ingår i: Contact Dermatitis. - : John Wiley & Sons. - 0105-1873 .- 1600-0536. ; 85, s. 340-353
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Tidskriftsartikel (refereegranskat)abstract
- Background: Tattoo inks have been reported to elicit allergic contact dermatitis.Objectives: To investigate the labels and the contents of metals and pigments in tattoo inks, considering restrictions within the European Union.Methods: 73 tattoo inks currently available on the market, either bought or donated (already used), were investigated for trace metals and pigments by inductively coupled plasma mass spectrometry and by matrix assisted laser desorption/ionization time of flight tandem mass spectrometry.Results: 93% of the bought tattoo inks violated European legal requirements on labeling. 50% of the tattoo inks declared at least one pigment ingredient wrongly. 61% inks contained pigments of concern, especially for red inks. Iron, aluminium, titanium, and copper (most in green/blue inks) were the main metals detected in the inks. The level of metal impurities was only in a few cases exceeding current restriction limits. Total chromium (0.35-139 µg/g) and nickel (0.1-41 µg/g) were found in almost all samples. The levels of iron, chromium, manganese, cobalt, nickel, zinc, lead, and arsenic were found to significantly covary.Conclusions: It is important for tattoo ink manufacturers to follow the regulations and decrease nickel and chromium impurities, to prevent contact allergy and toxic reactions among the users.
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