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  • 51.
    Lindgren, Johan
    et al.
    Lund University, Sweden.
    Sjövall, Peter
    RISE - Research Institutes of Sweden, Bioscience and Materials, Chemistry and Materials.
    Thiel, Volker
    University of Göttingen, Germany.
    Zheng, Wenxia
    North Carolina State University, USA.
    Ito, Shosuke
    Fujita Health University School of Health Sciences, Japan.
    Wakamatsu, Kazumasa
    Fujita Health University School of Health Sciences, Japan.
    Hauff, Rolf Bernhard
    Urweltmuseum Hauff, Germany.
    Kear, Benjamin P.
    Uppsala University, Sweden.
    Engdahl, Anders
    Lund University, Sweden.
    Alwmark, Carl
    Lund University, Sweden.
    Eriksson, Mats Erik
    Lund University, Sweden.
    Jarenmark, Martin
    Lund University, Sweden.
    Sachs, Sven
    Naturkunde-Museum Bielefeld, Germany.
    Ahlberg, Per Erik
    Uppsala University, Sweden.
    Marone, Federica
    Paul Scherrer Institute, Switzerland.
    Kuriyama, Takeo
    University of Hyogo, Japan; Wildlife Management Research Center, Japan.
    Gustafsson, Ola S.E.
    Lund University, Sweden.
    Malmberg, Per
    Chalmers University of Technology, Sweden.
    Thomen, Aurélien
    University of Gothenburg, Sweden.
    Rodríguez-Meizoso, Irene
    Lund University, Sweden.
    Uvdal, Per E.
    Lund University, Sweden.
    Ojika, Makoto
    Nagoya University, Japan.
    Schweitzer, Mary Higby
    Lund University, Sweden; North Carolina State University, USA; North Carolina Museum of Natural Sciences, USA.
    Soft-tissue evidence for homeothermy and crypsis in a Jurassic ichthyosaur2018In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 564, no 7736, p. 359-365Article in journal (Refereed)
    Abstract [en]

    Ichthyosaurs are extinct marine reptiles that display a notable external similarity to modern toothed whales. Here we show that this resemblance is more than skin deep. We apply a multidisciplinary experimental approach to characterize the cellular and molecular composition of integumental tissues in an exceptionally preserved specimen of the Early Jurassic ichthyosaur Stenopterygius. Our analyses recovered still-flexible remnants of the original scaleless skin, which comprises morphologically distinct epidermal and dermal layers. These are underlain by insulating blubber that would have augmented streamlining, buoyancy and homeothermy. Additionally, we identify endogenous proteinaceous and lipid constituents, together with keratinocytes and branched melanophores that contain eumelanin pigment. Distributional variation of melanophores across the body suggests countershading, possibly enhanced by physiological adjustments of colour to enable photoprotection, concealment and/or thermoregulation. Convergence of ichthyosaurs with extant marine amniotes thus extends to the ultrastructural and molecular levels, reflecting the omnipresent constraints of their shared adaptation to pelagic life.

  • 52.
    Lindgren, Johan
    et al.
    Lund University, Sweden.
    Uvdal, Per E.
    Lund University, Sweden.
    Sjövall, Peter
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Nilsson, Dan Eric
    Lund University, Sweden.
    Engdahl, Anders
    Lund University, Sweden.
    Schultz, Bo Pagh
    Museum Salling, Denmark.
    Thiel, Volker
    University of Göttingen, Germany.
    Molecular preservation of the pigment melanin in fossil melanosmoses2012In: Nature Communications, E-ISSN 2041-1723, Vol. 3, article id 824Article in journal (Refereed)
    Abstract [en]

    Fossil feathers, hairs and eyes are regularly preserved as carbonized traces comprised of masses of micrometre-sized bodies that are spherical, oblate or elongate in shape. For a long time, these minute structures were regarded as the remains of biofilms of keratinophilic bacteria, but recently they have been reinterpreted as melanosomes; that is, colour-bearing organelles. Resolving this fundamental difference in interpretation is crucial: if endogenous then the fossil microbodies would represent a significant advancement in the fields of palaeontology and evolutionary biology given, for example, the possibility to reconstruct integumentary colours and plumage colour patterns. It has previously been shown that certain trace elements occur in fossils as organometallic compounds, and hence may be used as biomarkers for melanin pigments. Here we expand this knowledge by demonstrating the presence of molecularly preserved melanin in intimate association with melanosome-like microbodies isolated from an argentinoid fish eye from the early Eocene of Denmark.

  • 53.
    Lu, X.
    et al.
    Nynas AB, Sweden.
    Sjövall, Peter
    RISE Research Institutes of Sweden, Materials and Production, Chemistry, Biomaterials and Textiles.
    Soenen, H.
    Nynas NV, Belgium.
    Blom, J.
    Antwerp University, Belgium.
    Makowska, M.
    Aalto University, Finland.
    Oxidative aging of bitumen: a structural and chemical investigation2022In: International Journal on Road Materials and Pavement Design, ISSN 1468-0629, E-ISSN 2164-7402, Vol. 23, no 5, p. 1091-1106Article in journal (Refereed)
    Abstract [en]

    The oxidative aging of bitumen was investigated chemically and structurally using SARA analysis, TOF-SIMS and AFM. Typical wax-containing and non-waxy bitumen samples were selected. Short- and long-term aging tests were conducted under standard conditions, and at prolonged aging times. For both the wax-containing and non-waxy bitumen, aging significantly decreases the aromatic fraction and at the same time increase the content of resins and asphaltenes. AFM shows bee-like structures on the wax-containing bitumen surface, and these structures change when the binder is aged. The bee structures are fewer but larger after a prolonged PAV. For the non-waxy bitumen, no structures were observed, even not after a severe PAV aging that increased the content of asphaltenes significantly. This implies that asphaltenes are most likely not responsible for the formation of bee structures. By TOF-SIMS, the non-waxy bitumen surface did not show structures, neither in the virgin state nor after the severe oxidative aging, further supporting that asphaltenes do not directly result in structure formation. For the wax-containing bitumen, TOF-SIMS shows aliphatics-enriched structures, which generally become larger after oxidative aging.

  • 54.
    Lu, Xiaohu
    et al.
    Nynas AB, Sweden.
    Sjövall, Peter
    RISE - Research Institutes of Sweden, Bioscience and Materials, Chemistry and Materials.
    Soenen, Hilde
    Nynas NV, Belgium.
    Andersson, Martin
    RISE - Research Institutes of Sweden, Bioscience and Materials, Surface, Process and Formulation.
    Microstructures of bitumen observed by environmental scanning electron microscopy (ESEM) and chemical analysis using time-of-flight secondary ion mass spectrometry (TOF-SIMS)2018In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 229, p. 198-208Article in journal (Refereed)
    Abstract [en]

    The aim of this study is to characterize structures induced on bitumen surfaces under analysis by environmental scanning electron microscopy (ESEM), and to examine possible contributing factors to the formation of their formation. Various bitumen samples are investigated, including soft and hard, as well as polymer modified bitumen. Chemical characterization is carried out by time-of-flight secondary ion mass spectrometry (TOF-SIMS), combined with principle component analysis (PCA). The study shows that, for soft bitumen, a tube pattern or worm structure is rapidly formed during ESEM analysis, but for hard bitumen, a longer exposure time is needed to develop a structure. The structures on the hard bitumen are also denser as compared to those on the soft bitumen. When sample specimens are deformed or stretched, the orientation of the created deformation is clearly reflected in the structures formed under ESEM, and for soft bitumen, the structure disappears overnight in vacuum but reappears with the same pattern upon repeated ESEM analysis. TOF-SIMS shows small but consistent chemical differences, indicating higher aliphatic and lower aromatic contents on the surface of the structured area compared to the unstructured area. Based on an estimated temperature increase on the bitumen surface due to the electron-beam irradiation, it is speculated that the ESEM-induced worm structure may be attributed to evaporation of volatiles, surface hardening and local expansion. In addition, under the electron-beam exposure, certain chemical reactions (e.g. breaking of chemical bonds, chain scission and crosslinking) may take place, possibly resulting in the observed chemical differences between the structured and unstructured areas.

  • 55.
    Lu, Xiaohu
    et al.
    Nynas AB, Sweden.
    Sjövall, Peter
    RISE - Research Institutes of Sweden (2017-2019), Bioscience and Materials, Chemistry and Materials.
    Soenen, Hilde
    Nynas NV, Belgium.
    Blom, Johan
    Antwerp University, Belgium.
    Andersson, Martin
    RISE - Research Institutes of Sweden (2017-2019), Bioscience and Materials, Surface, Process and Formulation.
    Structural and chemical imaging analysis of bitumen2021In: International Journal on Road Materials and Pavement Design, ISSN 1468-0629, E-ISSN 2164-7402, Vol. 22, no 4, p. 852-870Article in journal (Refereed)
    Abstract [en]

    Microstructures of bitumen surfaces (both air-cooled and fractured) were imaged by atomic force microscopy (AFM) and chemically characterised by time-of-flight secondary ion mass spectrometry (TOF-SIMS). For certain air-cooled bitumen surfaces, bee structures were observed by AFM, and chemical explanation by wax crystallisation was confirmed by TOF-SIMS analysis. Unlike the air-cooled surfaces, the fracture surfaces generally did not show clear structure patterns. Furthermore, TOF-SIMS analysis was conducted on the tube-like or worm structures which were generated by environmental scanning electron microscopy (ESEM) on the bitumen surfaces. In general, very small chemical differences were observed between the structured and unstructured areas, as well as between different areas of the structure. To understand the formation of the ESEM structures, possible contributing factors were examined, from which a mechanism involving electron-induced heating was proposed.

  • 56.
    Lu, Xiaohu
    et al.
    Nynas AB, Sweden.
    Sjövall, Peter
    RISE - Research Institutes of Sweden, Bioscience and Materials, Chemistry and Materials.
    Soenen, Hilde
    Nynas NV, Belgium.
    Blom, Johan
    Antwerp University, Belgium.
    Andersson, Martin
    RISE - Research Institutes of Sweden, Bioscience and Materials, Surface, Process and Formulation.
    Visualization and chemical analysis of bitumen microstructures2019In: RILEM Bookseries, 2019, p. 168-173Conference paper (Refereed)
    Abstract [en]

    Microstructures of bitumen were investigated using atomic force microscopy (AFM) and environmental scanning electron microscopy (ESEM), and a chemical characterization was successfully carried out using time-of-flight secondary ion mass spectrometry (TOF-SIMS). The bee structures were observed by AFM, for which a chemical explanation by wax was confirmed by the TOF-SIMS analysis. A tube pattern or worm structures were generated and visualized by ESEM on bitumen surfaces. Chemical differences between the structured and unstructured areas, as well as between different areas of the structure, were observed. A mechanism for the structure formation on bitumen surface during ESEM analysis is suggested.

  • 57.
    Lu, Xiaohu
    et al.
    Nynas AB, Sweden.
    Soenen, Hilde
    Nynas NV, Belgium.
    Sjövall, Peter
    RISE Research Institutes of Sweden, Materials and Production, Chemistry, Biomaterials and Textiles.
    Pipintakos, Georgios
    University of Antwerp, Belgium.
    Analysis of asphaltenes and maltenes before and after long-term aging of bitumen2021In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 304, article id 121426Article in journal (Refereed)
    Abstract [en]

    Asphaltenes and maltenes of bitumen before and after aging are investigated by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance spectroscopy (1H NMR), time of flight - secondary ion mass spectrometry (TOF-SIMS), and gel permeation chromatography (GPC). It has been shown that bitumen differs in terms of wax. After fractionation, more wax is found in the maltenes compared to the bitumen, and this is even more evident when bitumen is aged. For one bitumen, asphaltenes from the virgin binder do not contain carbonyls, which all fall into the maltenes. After bitumen aging, a large part of the carbonyl and sulfoxide signals is shifted to the asphaltenes. Differences in aromaticity are also evidenced as asphaltenes > bitumen > maltenes. TOF-SIMS shows that maltenes are close to the bitumen, but asphaltenes are more different. Also, maltenes are relatively unaffected by aging while larger differences are found in the asphaltenes between the virgin and aged binders. By GPC, a large molecular weight fraction of bitumen is shown as main part of the asphaltenes. However, asphaltenes also contain low molecular weight molecules that overlap with maltenes. Upon bitumen aging, some low molecular weight compounds may become part of asphaltenes, making the average molecular weight of the asphaltenes lower.

  • 58.
    Lu, Xiauhu
    et al.
    Nynas AB, Sweden.
    Sjövall, Peter
    RISE - Research Institutes of Sweden, Safety and Transport, Measurement Science and Technology.
    Soenen, Hilde
    Nynas NV, Belgium.
    Structural and chemical analysis of bitumen using time-of-flight secondary ion mass spectrometry (TOF-SIMS)2017In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 199, p. 206-218Article in journal (Refereed)
    Abstract [en]

    The chemical composition and structures of bitumen surfaces are characterised using time-of-flight secondary ion mass spectrometry (TOF-SIMS). The effect of wax is considered by comparing a wax-free bitumen with a bitumen that contains natural wax and a wax-free bitumen to which a small amount of wax has been added. The results demonstrate that TOF-SIMS is a powerful method for the chemical characterisation of surface structures and phase segregation phenomena in bitumen. It is evident that the structures formed on the bitumen surface are closely related to the wax content and that these structures, as well as the surface in general, are enriched in wax-related compounds (aliphatic hydrocarbons with a high degree of saturation). For the wax-free bitumen, the surface is characterised by a homogeneous distribution without chemical variations or phase structures and by a stronger signal intensity from aromatic compounds. When adding wax to the wax-free bitumen, extensive wax segregation occurs, but differently from the natural waxy bitumen, no bee structures are observed. Furthermore, fracture surfaces of all the wax-containing samples reveal circular structures, which are distinctly different from those observed on the original surfaces. The obtained chemical knowledge on bitumen surfaces and phase structures is of fundamental importance to understand performance differences of this type of materials.

  • 59. Magnusson, Y
    et al.
    Friberg, P
    Sjövall, Peter
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Dangardt, F
    Malmberg, P
    Chen, Y
    Lipid imaging of human skeletal muscle using TOF-SIMS with bismuth cluster ion as a primary ion source2008In: Clinical Physiology and Functional Imaging, ISSN 1475-0961, E-ISSN 1475-097X, Vol. 28, no 3, p. 202-209Article in journal (Refereed)
    Abstract [en]

    Intramyocellular lipids are of importance in lipid-related diseases. The techniques in this field are limited because of a lack of adequate tools for localization of various lipids. The most usual methods for the localization of lipid distribution in the skeletal muscle are histochemistry and fluorescence probes. Different chromatography methods and mass spectrometry techniques have also been used for lipid identification. Our aim was to localize the spatial distribution of lipids in their native forms by using static time-of-flight secondary-ion mass spectrometry (TOF-SIMS). Human percutaneous skeletal muscle biopsies were obtained from the middle part of the lateral vastus muscle in the right leg of healthy adolescents with a body mass index >30. Samples were prepared by high-pressure freezing, freeze-fracturing and freeze-drying, and analysed by imaging TOF-SIMS equipped with a Bi3+ cluster ion gun. In the positive spectra, we identified phosphocholine, cholesterol, diacylglycerol, phospholipids and triacylglycerol. Phosphocholine was localized to the edge of the fibre, representing the sarcoplasma or endomysium. Weak cholesterol signals were observed in the intracellular areas. High diacylglycerol and low triacylglycerol signal intensities were seen in intracellular spaces of the transversal area of the muscle fibre. In the negative spectra, we identified fatty acids. We observed co-localization of fatty acids and diacylglycerol, which may indicate lipid-storing parts of the skeletal muscle. Thus, TOF-SIMS imaging can be used to depict the heterogeneous localization of lipids in human skeletal muscle.

  • 60. Malm, J
    et al.
    Giannaras, D
    Riehle, MO
    Gadagaard, N
    Sjövall, Peter
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Fixation and drying protocols for the preparation of cell samples for time-of-flight secondary ion mass spectrometry analysis2009In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 81, no 17, p. 7197-7205Article in journal (Refereed)
    Abstract [en]

    Time-of-flight secondary ion mass spectrometry (TOFSIMS) is a promising tool for subcellular chemical analysis of biological cells. However, to obtain relevant information, the method used for sample preparation is critical. In this work, we have used TOF-SIMS, scanning electron microscopy (SEM), and interference reflection microscopy (IRM) to study the effects of different fixation and drying methods on the morphology and chemical structure of human fibroblast cells (hTERT) adhered to a silicon surface. Specifically, two fixation techniques (chemical fixation with glutaraldehyde and cryofixation by plunge freezing) and two drying techniques (freeze drying and alcohol substitution drying) were investigated. Cryofixation followed by freeze drying was determined to produce dried cells with preserved cell morphology, intact cell membranes, and retained sodium/potassium ion concentration gradients across the plasma membrane. By washing samples in an aqueous solution of ammonium formate (AF) before cryofixation, the accumulation of salts on the sample surface during drying could be suppressed. IRM measurements showed that the cell morphology was preserved during washing with ammonium formate, although some swelling occurred. Compared with cryofixation, cells fixed with glutaraldehyde showed finer structures on the cell surface in SEM and similar lipid distributions in TOF-SIMS, but the sodium/potassium ion gradients were not retained. Alcohol drying was determined to remove cell membrane phospholipids significantly, although the use of osmium tetroxide as a post-fixative was shown to decrease this effect.

  • 61. Maria de Peppo, Giuseppe
    et al.
    Bigdeli, Narmin
    Lennerås, Maria
    Sjövall, Peter
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Lindahl, Anders
    Karlsson, Camilla
    Hyllner, Johan
    Superior osteogenic capacity of human embryonic stem cells adapted to matrix-free growth compared to human mesenchymal stem cells2010In: Tissue Engineering A, Vol. 16, p. 3427-3440Article in journal (Refereed)
  • 62. Maria de Peppo, Giuseppe
    et al.
    Sjövall, Peter
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Lennerås, Maria
    Strehl, Raimund
    Hyllner, Johan
    Thomsen, Peter
    Karlsson, Camilla
    Osteogenic Potential of Human Mesenchymal Stem Cells and Human Embryonic Stem Cell-derived Mesodermal Progenitors: a Tissue Engineering Perspective2010In: Tissue Engineering A, Vol. 16, p. 3413-3426Article in journal (Refereed)
    Abstract [en]

    Tissue Engineering A, 16(11):3413-3426, 2010

  • 63.
    Möller, Kenneth
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Material och ytteknik.
    Jansson, Anna
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Polymer och fiber.
    Sjövall, Peter
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Analysis of oxidative polymer degradation using 18O and TOF-SIMS spectrometry2002Conference paper (Other academic)
  • 64.
    Möller, Kenneth
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Material och ytteknik.
    Jansson, Anna
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Polymer och fiber.
    Sjövall, Peter
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Degradation of post-consumer polypropylene materials exposed to simulated recycling – mechanical properties2003In: Polymer Degradation and Stability, Vol. 82, p. 37-46Article in journal (Refereed)
  • 65.
    Oorni, Katariina
    et al.
    Wihuri Research Institute, Finland.
    Lehti, Satu
    Wihuri Research Institute, Finland.
    Sjövall, Peter
    RISE - Research Institutes of Sweden (2017-2019), Bioscience and Materials, Chemistry and Materials.
    Kovanen, Petri T.
    Wihuri Research Institute, Finland.
    Triglyceride-Rich Lipoproteins as a Source of Proinflammatory Lipids in the Arterial Wall2019In: Current Medicinal Chemistry, ISSN 0929-8673, E-ISSN 1875-533X, Vol. 26, no 9, p. 1701-1710Article in journal (Refereed)
    Abstract [en]

    Apolipoprotein B -containing lipoproteins include triglyceride-rich lipoproteins (chylomicrons and their remnants, and very low-density lipoproteins and their remnants) and cholesterol-rich low-density lipoprotein particles. Of these, lipoproteins having sizes below 70-80 nm may enter the arterial wall, where they accumulate and induce the formation of atherosclerotic lesions. The processes that lead to accumulation of lipoprotein-derived lipids in the arterial wall have been largely studied with a focus on the low-density lipoprotein particles. However, recent observational and genetic studies have discovered that the triglyceriderich lipoproteins and their remnants are linked with cardiovascular disease risk. In this review, we describe the potential mechanisms by which the triglyceride-rich remnant lipoproteins can contribute to the development of atherosclerotic lesions, and highlight the differences in the atherogenicity between low-density lipoproteins and the remnant lipoproteins.[on SciFinder (R)]

  • 66.
    Pace, Hudson
    et al.
    Chalmers University of Technology, Sweden.
    Hannestad, Jonas
    RISE - Research Institutes of Sweden, Bioscience and Materials, Surface, Process and Formulation. Chalmers University of Technology, Sweden.
    Armonious, Antonius
    Chalmers University of Technology, Sweden.
    Adamo, Marco
    Institute Laue-Langevin, France ; Imperial College London, UK.
    Agnarsson, Bjorn
    Chalmers University of Technology, Sweden.
    Gunnarsson, Anders
    AstraZeneca, Sweden.
    Micciulla, Samantha
    Institute Laue-Langevin, France ; Max Planck Institute of Colloids and Interfaces, Germany.
    Sjövall, Peter
    RISE - Research Institutes of Sweden, Bioscience and Materials, Surface, Process and Formulation. Chalmers University of Technology, Sweden.
    Gerelli, Yuri
    Institute Laue-Langevin, France.
    Höök, Fredrik
    Chalmers University of Technology, Sweden.
    Structure and Composition of Native Membrane Derived Polymer-Supported Lipid Bilayers2018In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 90, no 21, p. 13065-13072Article in journal (Refereed)
    Abstract [en]

    Over the last two decades, supported lipid bilayers (SLBs) have been extensively used as model systems to study cell membrane structure and function. While SLBs have been traditionally produced from simple lipid mixtures, there has been a recent surge in compositional complexity to better mimic cellular membranes and thereby bridge the gap between classic biophysical approaches and cell experiments. To this end, native cellular membrane derived SLBs (nSLBs) have emerged as a new category of SLBs. As a new type of biomimetic material, an analytical workflow must be designed to characterize its molecular composition and structure. Herein, we demonstrate how a combination of fluorescence microscopy, neutron reflectometry, and secondary ion mass spectrometry offers new insights on structure, composition, and quality of nSLB systems formed using so-called hybrid vesicles, which are a mixture of native membrane material and synthetic lipids. With this approach, we demonstrate that the nSLB formed a continuous structure with complete mixing of the synthetic and native membrane components and a molecular stoichiometry that essentially mirrors that of the hybrid vesicles. Furthermore, structural investigation of the nSLB revealed that PEGylated lipids do not significantly thicken the hydration layer between the bilayer and substrate when on silicon substrates; however, nSLBs do have more topology than their simpler, purely synthetic counterparts. Beyond new insights regarding the structure and composition of nSLB systems, this work also serves to guide future researchers in producing and characterizing nSLBs from their cellular membrane of choice.

  • 67.
    Phan, Nhu T. N.
    et al.
    University of Gothenburg, Sweden; National Center Imaging Mass Spectrometry, Sweden.
    Fletcher, John S.
    University of Gothenburg, Sweden; National Center Imaging Mass Spectrometry, Sweden.
    Sjövall, Peter
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Ewing, Andrew G.
    University of Gothenburg, Sweden; National Center Imaging Mass Spectrometry, Sweden; Chalmers University of Technology, Sweden.
    TOf-SIMS imaging of lipids and lipid related compounds in Drosophila brain2014In: Surface and Interface Analysis, ISSN 0142-2421, E-ISSN 1096-9918, Vol. 46, no S1, p. 123-126Article in journal (Refereed)
    Abstract [en]

    Drosophila melanogaster (fruit fly) has a relatively simple nervous system but possesses high order brain functions similar to humans. Therefore, it has been used as a commonmodel system inbiological studies, particularly drug addiction. Here, the spatial distribution of biomolecules in the brain of the fly was studied using time-of-flight SIMS. Fly brains were analyzed frozen to prevent molecular redistribution prior to analysis. Different molecules were found to distribute differently in the tissue, particularly the eye pigments, diacylglycerides, and phospholipids, and this is expected to be driven by their biological functions in the brain. Correlations in the localization of these moleculeswere also observed using principal components analysis of image data, and this was used to identify peaks for further analysis. Furthermore, consecutive analyses following 10 keV Ar2500 + sputtering showed that different biomolecules respond differently to Ar2500 + sputtering. Significant changes in signal intensities between consecutive analyses were observed for high mass molecules including lipids.

  • 68.
    Pipintakos, Georgios
    et al.
    University of Antwerp, Belgium.
    Ching, H. Y. Vincent
    University of Antwerp, Belgium.
    Mühlich, Uwe
    University of Antwerp, Belgium.
    Soenen, Hilde
    Nynäs NV, Belgium.
    Van Doorslaer, Sabine
    University of Antwerp, Belgium.
    Sjövall, Peter
    RISE Research Institutes of Sweden, Materials and Production.
    Varveri, Aikaterini
    Delft University of Technology, The Netherlands.
    Vande Velde, Christophe
    University of Antwerp, Belgium.
    Lu, Xiaohu
    Nynäs AB, Sweden.
    Experimental Validation of the Dual-Oxidation Routes in Bituminous Binders2022In: RILEM Bookseries, Springer Science and Business Media B.V. , 2022, Vol. 27, p. 903-909Chapter in book (Refereed)
    Abstract [en]

    Oxidative ageing in bituminous materials is considered to be one of the most important factors for distress types in road applications. The increasing interest in oxidative ageing has highlighted the need for a thorough understanding of the oxidation mechanisms at molecular level. This paper offers some insight in the validity of the proposed hypotheses about the oxidation routes of bitumen, the fast- and the slow-rate route, reflecting on previous studies. Fourier-Transform Infrared (FTIR) and Electron Paramagnetic Resonance (EPR) spectroscopy were utilised for this verification. To elucidate the uncertain formation of sulfoxides, an additional surface investigation with Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) was performed. The findings of the aforementioned techniques reveal the existence of the oxidation products reported previously and contribute to the understanding of the oxidation mechanisms. Overall, this research strengthens experimentally the hypotheses of the dual-oxidation routes of bitumen. © 2022, The Author(s)

  • 69.
    Pipintakos, Giorgios
    et al.
    University of Antwerp, Belgium.
    Ching, Vincent
    University of Antwerp, Belgium.
    Soenen, Hilde
    Nynas NV, Belgium.
    Sjövall, Peter
    RISE Research Institutes of Sweden, Materials and Production, Chemistry, Biomaterials and Textiles.
    Mühlich, Uwe
    University of Antwerp, Belgium.
    Van Doorslaer, Sabine
    University of Antwerp, Belgium.
    Varveri, A.
    Delft University of Technology, Netherlands.
    Van den bergh, Wim
    University of Antwerp, Belgium.
    Lu, Xiaohu
    Nynas AB, Sweden.
    Experimental investigation of the oxidative ageing mechanisms in bitumen2020In: Construction and Building Materials, ISSN 0950-0618, E-ISSN 1879-0526, Vol. 260, article id 119702Article in journal (Refereed)
    Abstract [en]

    Oxidative ageing in bituminous materials is considered one of the most important factors for distress types in road applications. This paper aims to offer insights into the validity of commonly held beliefs regarding the oxidation phases of ageing in bitumen, the fast- and the slow-rate phase, and explore the main oxidation products formed upon ageing. In order to evaluate possible differences between bitumen types, the penetration grade as well as the bitumen production process was varied. Thus, the ageing of three different binders was first studied by Fourier-Transform Infrared (FTIR) and Electron Paramagnetic Resonance (EPR) spectroscopy. The formation of oxygen-containing molecular structures on the bitumen surface during ageing was studied with Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS). The results of FTIR reveal a gradual increase of sulfoxides upon ageing, while the EPR results show an increase of organic carbon-centred radicals. In parallel, TOF-SIMS results provide evidence for an increase of oxygenated compounds, such as SOx--, HOx-- and NOx--containing compounds. It appears also that paramagnetic metal species, such as vanadyl-porphyrins, are insusceptible during ageing. Overall, the findings of this study are in agreement with a mechanism comprising two rate-determining phases and support the formation of different oxygenated products. It is believed that the experimental approach used in this work may contribute further to an improved understanding of the ageing mechanisms in bitumen. 

  • 70. Prinz, Christelle
    et al.
    Malm, Jakob
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Höök, Fredrik
    Sjövall, Peter
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Structural effects in the analysis of supported lipid bilayers by time-of-flight secondary ion mass spectrometry (TOF-SIMS)2007In: Langmuir, Vol. 23, p. 8035-8041Article in journal (Refereed)
  • 71.
    Schweitzer, Mary
    et al.
    North Carolina State University, USA; North Carolina Museum of Natural Sciences, USA; Lund University, Sweden.
    Zheng, Wenxia
    North Carolina State University, USA.
    Moyer, Alison
    Drexel University, USA.
    Sjövall, Peter
    RISE - Research Institutes of Sweden, Bioscience and Materials, Chemistry and Materials.
    Lindgren, Johan
    Lund University, Sweden.
    Preservation potential of keratin in deep time2018In: PLOS ONE, E-ISSN 1932-6203, Vol. 13, no 11Article in journal (Refereed)
    Abstract [en]

    Multiple fossil discoveries and taphonomic experiments have established the durability of keratin. The utility and specificity of antibodies to identify keratin peptides has also been established, both in extant feathers under varying treatment conditions, and in feathers from extinct organisms. Here, we show localization of feather-keratin antibodies to control and heat-treated feathers, testifying to the repeatability of initial data supporting the preservation potential of keratin. We then show new data at higher resolution that demonstrates the specific response of these antibodies to the feather matrix, we support the presence of protein in heat-treated feathers using ToF-SIMS, and we apply these methods to a fossil feather preserved in the unusual environment of sinter hot springs. We stress the importance of employing realistic conditions such as sediment burial when designing experiments intended as proxies for taphonomic processes occurring in the fossil record. Our data support the hypothesis that keratin, particularly the β-keratin that comprises feathers, has potential to preserve in fossil remains.

  • 72.
    Siljeström, S
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Lausmaa, J
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Sjövall, Peter
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Broman, C
    Thiel, V
    Hode, T
    Analysis of hopanes and steranes in single oil-bearing fluid inclusions using time-og-flight secondary ion mass spectrometry (ToF-SIMS)2010In: Geobiology, ISSN 1472-4677, E-ISSN 1472-4669, Vol. 8, no 1, p. 37-44Article in journal (Refereed)
    Abstract [en]

    Steranes and hopanes are organic biomarkers used as indicators for the first appearance of eukaryotes and cyanobacteria on Earth. Oil-bearing fluid inclusions may provide a contamination-free source of Precambrian biomarkers, as the oil has been secluded from the environment since the formation of the inclusion. However, analysis of biomarkers in single oil-bearing fluid inclusions, which is often necessary due to the presence of different generations of inclusions, has not been possible due to the small size of most inclusions. Here, we have used time-of-flight secondary ion mass spectrometry (ToF-SIMS) to monitor in real time the opening of individual inclusions trapped in hydrothermal veins of fluorite and calcite and containing oil from Ordovician source rocks. Opening of the inclusions was performed by using a focused C 60+ ion beam and the in situ content was precisely analysed for C27-C29 steranes and C29-C 32 hopanes using Bi3+ as primary ions. The capacity to unambiguously detect these biomarkers in the picoliter amount of crude oil from a single, normal-sized (15-30 μm in diameter) inclusion makes the approach promising in the search of organic biomarkers for life's early evolution on Earth.

  • 73.
    Siljeström, Sandra
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Hode, Tomas
    Lausmaa, Jukka
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Toporski, Jan
    Thiel, Volker
    Sjövall, Peter
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Detection of biomarkers in oils using ToF-SIMS2007In: Geochimica et Cosmochimica Acta, Vol. 71, no 15, p. A937-Article in journal (Refereed)
  • 74.
    Siljeström, Sandra
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Lausmaa, Jukka
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Hode, T
    Sundin, Mikael
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet. RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Sjövall, Peter
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Structural effects of C-60(+) bombardment on various natural mineral samples - Application to analysis of organic phases in geological samples2011In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 257, no 21, p. 9199-9206Article in journal (Refereed)
    Abstract [en]

    Organic phases trapped inside natural mineral samples are of considerable interest in astrobiology, geochemistry and geobiology. Examples of such organic phases are microfossils, kerogen and oil. Information about these phases is usually retrieved through bulk crushing of the rock which means both a risk of contamination and that the composition and spatial distribution of the organics to its host mineral is lost. An attractive of way to retrieve information about the organics in the rock is depth profiling using a focused ion beam. Recently, it was shown that it is possible to obtain detailed mass spectrometric information from oil-bearing fluid inclusions, i.e. small amounts of oil trapped inside a mineral matrix, using ToF-SIMS. Using a 10 keV C-60(+) sputter beam and a 25 keV Bi-3(+) analysis beam, oil-bearing inclusions in different minerals were opened and analysed individually. However, sputtering with a C-60(+) beam also induced other changes to the mineral surface, such as formation of topographic features and carbon deposition. In this paper, the cause of these changes is explored and the consequences of the sputter-induced features on the analysis of organic phases in natural mineral samples (quartz, calcite and fluorite) in general and fluid inclusions in particular are discussed. The dominating topographical features that were observed when a several micrometers deep crater is sputtered with 10 keV C-60(+) ions on a natural mineral surface are conical-shaped and ridge-like structures that may rise several micrometers, pointing in the direction of the incident C-60(+) ion beam, on an otherwise flat crater bottom. The sputter-induced structures were found to appear at places with different chemistry than the host mineral, including other minerals phases and fluid inclusions, while structural defects in the host material, such as polishing marks or scratches, did not necessarily result in sputter-induced structures. The ridge-like structures were often covered by a thick layer of deposited carbon. Despite the appearance of the sputter-induced structures and carbon deposition, most oil-bearing inclusions could successfully be opened and analysed. However, smaller inclusion (

  • 75.
    Siljeström, Sandra
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Lausmaa, Jukka
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Sjövall, Peter
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Hode, Tomas
    Thiel, Volker
    Heim, Christine
    ToF-SIMS possibilities in geobiology2008In: Astrobiology, Vol. 8, no 2, p. 329-Article in journal (Refereed)
  • 76.
    Siljeström, Sandra
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Lausmaa, Jukka
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Sjövall, Peter
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Thiel, Volker
    Hode, Tomas
    Heim, Christine
    Detection of organic biomarkers in crude oils using ToF-SIMS2008In: Organic Chemistry, Vol. 40, no 1, p. 135-143Article in journal (Refereed)
  • 77.
    Siljeström, Sandra
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Sjövall, Peter
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Biomarker imaging of single diatom cells in a microbial mat using time-of-flight secondary ion mass spectrometry (ToF-SIMS)2013In: Organic Geochemistry, ISSN 0146-6380, E-ISSN 1873-5290, Vol. 57, no Apr, p. 23-33Article in journal (Refereed)
  • 78.
    Siljeström, Sandra
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Volk, Herbert
    CSIRO Earth Science and Resource Engineering, Australia; BP Exploration Operating Company Ltd, United Kingdom.
    George, Simon C.
    Macquarie University, Australia.
    Sjövall, Peter
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Dutkiewicz, Adriana
    University of Sydney, Australia.
    Hode, Tomas
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor.
    Analysis of single oil-bearing fluid inclusions in mid-Proterozoic sandstones (Roper Group, Australia)2013In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 122, p. 448-463Article in journal (Refereed)
    Abstract [en]

    Hydrocarbons and organic biomarkers extracted from black shales and other carbonaceous sedimentary rocks are valuable sources of information on the biodiversity and environment of early Earth. However, many Precambrian hydrocarbons including biomarkers are suspected of being younger contamination. An alternative approach is to study biomarkers trapped in oil-bearing fluid inclusions by bulk crushing samples and subsequently analysing the extracted hydrocarbons with gas chromatography-mass spectrometry. However, this method does not constrain the hydrocarbons to one particular oil inclusion, which means that if several different generations of oil inclusions are present in the sample, a mix of the content from these oil inclusions will be analysed. In addition, samples with few and/or small inclusions are often below the detection limit. Recently, we showed that it is possible to detect organic biomarkers in single oil-bearing fluid inclusions using time-of-flight secondary ion mass spectrometry (ToF-SIMS). In the present study, single fluid inclusion analysis has been performed on Proterozoic samples for the first time. Four individual oil-bearing fluid inclusions, found in 1430. Ma sandstone from the Roper Superbasin in Northern Australia, were analysed with ToF-SIMS. The ToF-SIMS spectra of the oil in the different inclusions are very similar to each other and are consistent with the presence of n-alkanes/branched alkanes, monocyclic alkanes, bicyclic alkanes, aromatic hydrocarbons, and tetracyclic and pentacyclic hydrocarbons. These results are in agreement with those obtained from bulk crushing of inclusions trapped in the same samples. The capability to analyse the hydrocarbon and biomarker composition of single oil-bearing fluid inclusions is a major breakthrough, as it opens up a way of obtaining molecular compositional data on ancient oils without the ambiguity of the origin of these hydrocarbons. Additionally, this finding suggests that it will be possible to analyse minute oil samples beyond the capability of established techniques. This may allow the biomarker record of the biosphere, as preserved in fluid inclusions, to be extended further back in time, and hence makes it possible to more accurately trace the early evolution of life on Earth, and search for life on other planets or moons.

  • 79.
    Sjövall, Peter
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Chemical and structural analysis of the bone-implant interface by TOF-SIMS, SEM, FIB and TEM: Experimental study in animal2012In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 258, no 17, p. 6485-6494Article in journal (Refereed)
  • 80.
    Sjövall, Peter
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Chemical characterization of combustion deposits by TOF-SIMS2003In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 203, no 203, p. 669-672Article in journal (Other academic)
  • 81.
    Sjövall, Peter
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Kemisk/fysikalisk karaktärisering av avlagringar2001Report (Refereed)
  • 82.
    Sjövall, Peter
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Localization of cholesterol, amyloid and glia in Alzheimer's disease transgenic mouse brain tissue using time-of-flight secondary ion mass spectrometry (ToF-SIMS) and immunofluorescence imaging2013In: Acta Neuropathologica, ISSN 0001-6322, E-ISSN 1432-0533, Vol. 125, no 1, p. 145-157Article in journal (Refereed)
  • 83.
    Sjövall, Peter
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Metabolic effects of n-3 PUFA as phospholipids are superior to triglycerides in mice fed a high-fat diet: Possible role of endocannabinoids2011In: PLOS ONE, E-ISSN 1932-6203, Vol. 7, no 6, p. e38834-Article in journal (Refereed)
  • 84.
    Sjövall, Peter
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Post-glacial microbialite formation in coral reefs of the Pacific, Atlantic, and Indian Oceans2012In: Chemical Geology, ISSN 0009-2541, E-ISSN 1872-6836, Vol. 304, no Apr, p. 117-130Article in journal (Refereed)
  • 85.
    Sjövall, Peter
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Relative quantification of phospholipid accumulation in the PC12 cell plasma membrane following phospholipid incubation using TOF-SIMS imaging2011In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 83, no 13, p. 5337-5343Article in journal (Refereed)
  • 86.
    Sjövall, Peter
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Surface analysis of precision weights for the study of commonly occurring contaminants2005In: Nanoscale calibration standards and methods, 2005, p. 434-442Chapter in book (Other (popular science, discussion, etc.))
  • 87.
    Sjövall, Peter
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    TOF-SIMS imaging of spatial distribution of lipids in cells2002Conference paper (Other academic)
  • 88.
    Sjövall, Peter
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Using time-of-flight secondary ion mass spectrometry to study biomarkers2011In: Annual Review of Earth and Planetary Science, ISSN 0084-6597, E-ISSN 1545-4495, Vol. 39, p. 125-156Article in journal (Refereed)
  • 89.
    Sjövall, Peter
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf). Chalmers University of Technology, Sweden.
    Agnarsson, Björn
    Chalmers University of Technology, Sweden.
    Carlred, Louise
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Kemi Material och Ytor, Medicinteknik. Chalmers University of Technology, Sweden.
    Gunnarsson, Anders
    Chalmers University of Technology, Sweden.
    Höök, Fredrik F.
    Chalmers University of Technology, Sweden.
    Liposome binding for multiplexed biomolecule detection and imaging using ToF-SIMS2014In: Surface and Interface Analysis, ISSN 0142-2421, E-ISSN 1096-9918, Vol. 46, no 10-11, p. 707-711Article in journal (Refereed)
    Abstract [en]

    A novel approach for multiplexed biomolecule detection at surfaces, involving specific binding of liposomes and subsequent analysis by time-of-flight secondary ion mass spectrometry (ToF-SIMS), was evaluated with respect to its capability for quantitative analysis of biomolecule surface concentrations. The specific binding of liposomes to a poly(L-lysine)-g-poly (ethylene glycol) (PLL-g-PEG) surface, using the biotin-avidin coupling chemistry, was characterized by quartz crystal microbalance with dissipation monitoring (QCM-D), fluorescence microscopy and ToF-SIMS. The ToF-SIMS results showed a linearly increasing signal from the liposomes up to a saturation coverage corresponding to a full liposome layer on the surface, in close agreement with fluorescence microscopy analysis of the same samples, strongly supporting the potential of the liposome-based approach for quantitative biomolecule detection. However, the multiplexing capability and issues on nonspecific binding need further studies. Furthermore, an improved method for the preparation of lipid bilayer samples for ToF-SIMS analysis is presented, demonstrating the imaging of individual 210-nm diameter liposomes adsorbed on a SiO2 surface.

  • 90.
    Sjövall, Peter
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Almstrand, Ann-Charlotte
    Ljungström, Evert
    Bake, Björn
    Bredberg, Anna
    Olin, Anna-Carin
    Lausmaa, Jukka
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Airway monitoring by collection and mass spectrometric analysis of exhaled particles2009In: Analytical Chemistry, Vol. 81, no 2, p. 662-8Article in journal (Refereed)
  • 91.
    Sjövall, Peter
    et al.
    RISE Research Institutes of Sweden, Materials and Production, Chemistry, Biomaterials and Textiles.
    Bake, Kyle
    Schlumberger-Doll Research, USA.
    Pomerantz, Andrew
    Schlumberger-Doll Research, USA.
    Lu, Xiaohu
    Nynäs AB, Sweden.
    Mitra-Kirtley, Sudipa
    Rose-Hulman Institute of Technology, USA.
    Mullins, Oliver
    Schlumberger-Doll Research, USA.
    Analysis of kerogens and model compounds by time-of-flight secondary ion mass spectrometry (TOF-SIMS)2021In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 286, article id 119373Article in journal (Refereed)
    Abstract [en]

    Here, kerogens of differing heat treatments are subjected to extremely high dissociation energies by sample bombardment by 25 keV Bi3+ primary ions during analysis by time-of-flight secondary ion mass spectrometry (TOF-SIMS). Positive and negative secondary ions are produced from this decomposition and fragment ion distributions of model compounds and kerogens are compared and starkly different results are obtained for cations versus anions. Cations exhibit a large range of C/H ratios and include highly unsaturated linear chain ions and aromatic ions. Cations of kerogens possess predominantly no heteroatoms. Positive fragment ion distributions depend on the source material being bombarded. Mature, more aromatic kerogens produce higher yields of fragment ions of highly unsaturated carbon chains while immature, more aliphatic kerogens produce more aromatic fragment ions, particularly at the higher carbon numbers. This is consistent with the observation that aromatic model compounds produce a greater fraction of hydrogen-deficient, carbon chain fragment ions, as compared to a purely aliphatic model compound. There is substantial suppression of free radical fragment cations, except for large fragments. In contrast, there is little free radical suppression of the anions. The anions tend to be very hydrogen deficient, spanning a small range of C/H ratios. Highly unsaturated to pure carbon chain fragment anions dominate while aromatic anions are not found. In both positive and negative ion spectra, the yields of fragment ions corresponding to derivatives of the carbon chain molecules, polyynes and allenes, are substantial. Some heteroatom-containing fragment anions are produced, all of which are very hydrogen deficient. 

  • 92.
    Sjövall, Peter
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Belazi, D
    Solé Domenèch, Santiago
    Johansson, Björn
    Schalling, Martin
    Chemical analysis of osmium tetroxide staining in adipose tissue using imaging ToF-SIMS2009In: Histochemistry and Cell Biology, Vol. 132, no 1, p. 105-15Article in journal (Other academic)
  • 93.
    Sjövall, Peter
    et al.
    RISE Research Institutes of Sweden, Materials and Production, Product Realisation Methodology.
    Gregoire, Sebastien
    L’Oréal Research and Innovation, France.
    Wargniez, William
    L’Oréal Research and Innovation, France.
    Skedung, Lisa
    RISE Research Institutes of Sweden, Bioeconomy and Health, Material and Surface Design.
    Luengo, Gustavo
    L’Oréal Research and Innovation, France.
    3D Molecular Imaging of Stratum Corneum by Mass Spectrometry Suggests Distinct Distribution of Cholesteryl Esters Compared to Other Skin Lipids2022In: International Journal of Molecular Sciences, ISSN 1661-6596, E-ISSN 1422-0067, Vol. 23, no 22, article id 13799Article in journal (Refereed)
    Abstract [en]

    The crucial barrier properties of the stratum corneum (SC) depend critically on the design and integrity of its layered molecular structure. However, analysis methods capable of spatially resolved molecular characterization of the SC are scarce and fraught with severe limitations, e.g., regarding molecular specificity or spatial resolution. Here, we used 3D time-of-flight secondary ion mass spectrometry to characterize the spatial distribution of skin lipids in corneocyte multilayer squams obtained by tape stripping. Depth profiles of specific skin lipids display an oscillatory behavior that is consistent with successive monitoring of individual lipid and corneocyte layers of the SC structure. Whereas the most common skin lipids, i.e., ceramides, C24:0 and C26:0 fatty acids and cholesteryl sulfate, are similarly organized, a distinct 3D distribution was observed for cholesteryl oleate, suggesting a different localization of cholesteryl esters compared to the lipid matrix separating the corneocyte layers. The possibility to monitor the composition and spatial distribution of endogenous lipids as well as active drug and cosmetic substances in individual lipid and corneocyte layers has the potential to provide important contributions to the basic understanding of barrier function and penetration in the SC. © 2022 by the authors.

  • 94.
    Sjövall, Peter
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Greve, Tanja Maria
    LEO Pharma A/S, Denmark.
    Clausen, Susanne K.
    LEO Pharma A/S, Denmark.
    Möller, Kristian
    LEO Pharma A/S, Denmark.
    Eirefelt, Stefan J.
    LEO Pharma A/S, Denmark.
    Johansson, Björn
    Karolinska Institute, Sweden.
    Nielsen, Kim Troensegaard
    LEO Pharma A/S, Denmark.
    Imaging of distribution of topically applied drug molecules in mouse skin by combination of time-of-flight secondary ion mass spectrometry and scanning electron microscopy2014In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 86, no 7, p. 3443-3452Article in journal (Refereed)
    Abstract [en]

    In the development of topical drugs intended for local effects in the skin, one of the major challenges is to achieve drug penetration through the external barrier of the skin, stratum corneum, and secure exposure to the viable skin layers. Mass spectrometric imaging offers an opportunity to study drug penetration in a variety of skin models by mapping the spatial distribution indifferent skin layers after topical application of the drug. In this study, we used time-of-flight secondary ion mass spectrometry (TOF-SIMS) and scanning electron microscopy (SEM) to image the distribution of three drug molecules in skin tissue cross sections of inflamed mouse ear. The three compounds, roflumilast, tofacitinib, and ruxolitinib, were topically administered to the mouse ears, which were subsequently cryosectioned and thawed for the analyses. The results reveal that the combination of TOF-SIMS and SEM was beneficial for interpretation of drug distribution. SEM identified the different skin layers, while spatial distributions of all three compounds could be visualized by TOF-SIMS, showing that the drug was primarily distributed into, or on the top of, the stratum corneum. Imaging of endogenous skin components like cholesterol, phospholipids, ceramides, and free fatty acids showed distributions in good agreement with the literature. One limitation of the TOF-SIMS method is sensitivity, typically allowing for analysis in the millimolar range rather than the pharmacologically relevant micromolar range. However, the data presented demonstrate the potential of the technique for studying the penetration of drugs with different physicochemical properties in skin.

  • 95.
    Sjövall, Peter
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Lanekoff, Ingela
    Kurczy, Michael E.
    Adams, Kelly L.
    Malm, Jakob
    Karlsson, Roger
    Ewing, Andrew
    An in situ fracture device to image lipids in single cells using TOF-SIMS2011In: Surface and Interface Analysis, Vol. 43, no 1-2, p. 257-260Article in journal (Refereed)
  • 96.
    Sjövall, Peter
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Lausmaa, Jukka
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Chemical characterisation of different separation media based on agarose by static time-of-flight secondary ion mass spectrometry2004In: Journal of Chromatography A, Vol. 1023, no 1023, p. 49-56Article in journal (Refereed)
  • 97.
    Sjövall, Peter
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Lausmaa, Jukka
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Chemical characterization of combusion deposits by TOF-SIMS2001Conference paper (Other academic)
  • 98.
    Sjövall, Peter
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Lausmaa, Jukka
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Mass spectrometric imaging of lipids in brain tissue2004In: Anal. Chem, Vol. 76, p. 4271-4278Article in journal (Refereed)
  • 99.
    Sjövall, Peter
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Lausmaa, Jukka
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, SP – Sveriges Tekniska Forskningsinstitut / Funktionella material (KMf).
    Surface Chemical Analysis of Carbohydrate Materials Used for Chromatography Media by Time-of-Flight Secondary Ion Mass Spectrometry2004In: Analytical Chemistry, Vol. 76, no 76, p. 1857-1864Article in journal (Refereed)
  • 100.
    Sjövall, Peter
    et al.
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    Lausmaa, Jukka
    RISE, SP – Sveriges Tekniska Forskningsinstitut, SP Sveriges tekniska forskningsinstitut, YKI – Ytkemiska institutet.
    ToF-SIMS2011In: Encyclopedia of Geobiology / [ed] Joachim Reitner, Volker Thiel, Springer Netherlands, 2011, p. 883-886Chapter in book (Refereed)
123 51 - 100 of 125
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