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  • 51.
    Lloyd-Spets, Anita
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Steinhoff, Georg
    Petoral, Rodrigo Jr
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Uvdal, Kajsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Eickhoff, Martin
    Yakimova, Rositsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    New Materials for Multifunctional Chemical- and Biosensors2006In: MST06 Chemically Active Ceramic Nano-Particles and Nano-Structures,2006, 2006Conference paper (Refereed)
    Abstract [en]

      

  • 52.
    Lloyd-Spets, Anita
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Uvdal, Kajsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Eickhoff, Martin
    Walter Schottky Inst. München Univresity.
    Katardjiev, Ilia
    Uppsala universitet.
    Yakimova, Rositsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Wide band-gap materials for chemical and biosensors2005In: International Symposium for Advanced Sensor Technologies,2005, 2005, p. 25-30Conference paper (Refereed)
  • 53.
    Marciniak Braun, Slawomir
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Crispin, Xavier
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Trzcinski, M.
    Institute of Mathematics and Physics, Bydgoszcz, Poland.
    Birgerson, J.
    LCD Technology, Dalarna University, Borlänge, Sweden.
    Groenendaal, L.
    Agfa-Gevaert N. V., R&D Materials/Chemistry Department, Mortsel, Belgium.
    Louwet, F.
    Agfa-Gevaert N. V., R&D Materials/Chemistry Department, Mortsel, Belgium.
    Salaneck, William R.
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Light Induced Damage in Poly(3,4-ethylenedioxythiophene) and its Derivatives Studied by Photoelectron Spectroscopy2004In: Synthetic metals, ISSN 0379-6779, E-ISSN 1879-3290, Vol. 141, no 1-2, p. 67-73Article in journal (Refereed)
    Abstract [en]

    Poly(3,4-ethylenedioxythiophene), usually known as PEDOT, and derivatives have attracted significant interest because of their high electrical conductivity. This electric property, however, deteriorates upon exposure to solar radiation. X-ray photoelectron spectroscopy (XPS) has been used to study the UV-light-induced chemical changes in doped PEDOT, as well as in both neutral and doped forms of its alkylated derivative—PEDOT-C14H29. Analysis of the XPS data indicates an oxidation of the sulfur in the thiophene ring. Apparently, photo-oxidation leads to the formation of sulfon groups, SO2, resulting in a disruption of π-conjugation in PEDOT, which there by diminishes the conductivity of the organic layer. This hypothesis is supported by the results of a study of model molecules for pristine and the oxidized PEDOT unit: 3,4 ethylenedioxythiophene (EDOT) and 3,4 ethylenedioxythiophene and S-dioxide (EDOT-SO2), respectively.

  • 54.
    Pedersen, Henrik
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Söderlind, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Petoral, Rodrigo M.
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Käll, Per-Olov
    Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry. Linköping University, The Institute of Technology.
    Ojamäe, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry. Linköping University, The Institute of Technology.
    Surface interactions between Y2O3 nanocrystals and organic molecules—an experimental and quantum-chemical study2005In: Surface Science, ISSN 0039-6028, E-ISSN 1879-2758, Vol. 592, no 1-3, p. 124-140Article in journal (Refereed)
    Abstract [en]

    The surface interactions between Y2O3 nanocrystals and the organic molecules formic acid, diethylene glycol (DEG), and tetramethoxy silane (TMOS), have been studied experimentally and by quantum chemical calculations with the intent to elucidate the chemisorption characteristics such as adsorbate vibrational spectra and adsorption structures. Nanocrystal synthesis was performed by a colloidal method based on polyols and by a rapid combustion method. The products were experimentally characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS).

    In the quantum chemical calculations, the B3LYP hybrid density functional ab initio method was used to study the chemisorption of formic acid, DEG and TMOS at the surface of Y12O18 clusters. From a comparison of calculated and experimental vibrational spectra, the binding mode for formic acid on Y2O3 was inferred to be of bridge or bidentate type. The XPS and FT-IR experiments showed that DEG is chemisorbed on the particle surface. The experimental IR spectra of DEG chemisorbed on Y2O3 were consistent with an adsorption mode where the hydroxyl groups are deprotonated according to the quantum-chemical computations. The adsorption energy is of the order of 370 kJ mol−1 for formic acid, 550 kJ mol−1 for DEG, and 60 kJ mol−1 for TMOS, according to the quantum chemical calculations.

  • 55.
    Persson, Nils-Ola
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Almquist, Ola
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Engquist, Isak
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Kariis, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Liedberg, Bo
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Adsorption of potassium O,O -Di(para-fluorophenyl) dithiophosphate on gold, silver, and copper1999In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 15, no 23, p. 8161-8169Article in journal (Refereed)
    Abstract [en]

    Gold, silver, and copper substrates were immersed in aqueous solutions of a simulant mineral flotation agent, potassium O,O-di(para-fluorophenyl) dithiophosphate. The adsorbed molecules on gold were studied in detail with infrared reflection-absorption spectroscopy (IRAS), X-ray photoelectron spectroscopy(XPS), and ellipsometry. The most significant peaks in the IRAS spectra were assigned to the appropriate molecular vibrations and their relative intensities were compared with those found in simulated spectra derived from the isotropic optical constants of corresponding metal salts to deduce the binding and orientation. Moreover, intensity ratios of XPS signals were compared at different takeoff angles to reveal the depth distribution of atoms in the dithiophosphate layers. The following modes of adsorption were deduced: The adsorption on gold takes place by the formation of bonds involving the two sulfur atoms of the flotation agent (bridging coordination), regardless of immersion time and solution concentration. A thin and less organized layer is formed at low exposures. Longer adsorption times with more concentrated solutions give a more dense molecular packing and vertical orientation of the molecules on the surface. Adsorption on silver and copper was studied by IRAS. The adsorption proceeded via a dissolution-precipitation mechanism that manifests itself by less pronounced orientation effects. The intensities of the silver and copper IRAS spectra after long immersion times in concentrated solutions also show the formation of multilayers with some persisting long-range molecular ordering.

  • 56.
    Petoral Jr., Rodrigo M.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Herland, Anna
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Broo, Kerstin
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    G-protein interactions with receptor-derived peptides chemisorbed on gold2003In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 19, no 24, p. 10304-10309Article in journal (Refereed)
    Abstract [en]

    Interactions between the functional bovine brain G-protein and receptor-derived peptidea chemically adsorbed on gold surfaces are studied. The peptides are designed to mimic the third ic-loop (aa 361-373) of the Alpha 2a-adrenergic receptor (α 2AR). These segments are linked to a surface using the thiol-gold chemistry, and the protein interaction studies are conducted to investigate the key function of recognition. The chemical composition and binding strength of the peptide monolayers onto a gold surface are characterized using X-ray photoelectron spectroscopy and infrared (IR) spectroscopy. Strong molecular binding of the adsorbates to the gold surface is attained, and the presence of amide-related IR vibrations verified the composition of the peptides. Bovine brain G-protein adsorption studies on these molecular monolayers are performed using the surface plasmon resonance technique. The arginine-rich peptide, which is a direct mimicry of the receptor, has a higher affinity for G-protein than the lysine-rich and alanine-rich derived peptides, showing that arginine residue has special importance for the G-protein interaction with the receptor.

  • 57.
    Petoral, Rodrigo Jr
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Arg–Cys and Arg–cysteamine adsorbed on gold and the G-protein–adsorbate interaction2002In: Colloids and Surfaces B: Biointerfaces, ISSN 0927-7765, E-ISSN 1873-4367, Vol. 25, no 4, p. 335-346Article in journal (Refereed)
    Abstract [en]

    The dipeptide, Arg–Cys, and the related molecule, Arg–cysteamine, are adsorbed to gold surfaces and the monolayers are characterized. Chemical binding and electronic structure of the monolayers are obtained by X-ray photoelectron spectroscopy (XPS). Strong molecular binding of the adsorbates to gold surface through the sulfur atom is attained. Orientation of the adsorbates on gold is studied using infrared reflection absorption spectroscopy (IRAS). Arg–Cys is interpreted to be adsorbed on gold in a compact configuration. The Arg–cysteamine molecule is adsorbed on gold with the main molecular axis perpendicular to the surface. Interaction of G-protein with the adsorbates was studied using the surface plasmon resonance (SPR) technique. It is believed that arginine has a major role in G-protein recognition since the G-protein-coupled receptor (GPCR) α2A has an arginine-rich region in the G-protein-binding part of the third intracellular loop.

  • 58.
    Petoral, Rodrigo Jr
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Uvdal, Kajsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Chemisorption of Aromatic Amino Acid Derivatives on Gold Surfaces2003In: AVS 2003,2003, 2003Conference paper (Other academic)
  • 59.
    Petoral, Rodrigo Jr
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Uvdal, Kajsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    NEXAFS study of amino acid analogues assembled on gold2003In: XAFS12,2003, 2003Conference paper (Other academic)
  • 60.
    Petoral, Rodrigo Jr
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Uvdal, Kajsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    NEXAFS study of amino acid analogues assembled on gold2005In: Physica scripta. T, ISSN 0281-1847, Vol. T115, p. 851-854Article in journal (Refereed)
    Abstract [en]

    In this work, near-edge x-ray absorption fine structure spectroscopy (NEXAFS) experiment is done to obtain the chemical and structural information about the occurrence and the average orientation of unoccupied molecular orbitals within the organic films. Amino acid, such as Tyrosine and 3,4-dihydroxyphenylalanine (DOPA), is linked to a thiol through a peptide bond and is adsorbed and self-assembled to polycrystalline gold surfaces. Results from the C k-edge and O k-edge spectra serves as fingerprints to each amino acid analogues. The average orientation of the molecules relative to the gold surface is determined from the polarization effects observed as intensity changes of the peaks in the spectra when the x-ray incidence angle is varied. It is assumed that the average tilt angle of the main molecular axis of amino acid linked to short amidethiol is based on the deduced orientation of the peptide bond. © Physica Scripta 2005.

  • 61.
    Petoral, Rodrigo Jr
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Structural investigation of 3,4-dihydroxyphenylalanine-terminated propanethiol assembled on gold2003In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 107, no 48, p. 13396-13402Article in journal (Refereed)
    Abstract [en]

    3,4-Dihydroxyphenylalanine-terminated propanethiol (DOPA-PT), an amino acid DOPA linked to 3-mercaptopropionic acid through an amide bond, is adsorbed and self-assembled to polycrystalline gold surfaces. The structure of the adsorbates was characterized by means of X-ray photoelectron spectroscopy (XPS), infrared reflection−absorption spectroscopy (IRAS), and near-edge X-ray absorption fine structure spectroscopy (NEXAFS). Strong molecular binding of a DOPA derivative on gold surfaces through the sulfur atom was attained. Angle-dependent XPS results showed that the aromatic ring is oriented away from the gold surface. Both IRAS and NEXAFS results showed parallel orientation of the C=O bond of the amide moiety relative to the gold surface. Hydrogen bonding between amide moieties is achieved, and it seemed to provide additional orientation stabilization. Deduced orientation of the amide moiety on the short alkyl chain (or the peptide plane) is assumed to give the average orientation of the main molecular axis. The main molecular axis is estimated to have an average tilt angle of approximately 37° relative to the gold surface normal based on NEXAFS results. The aromatic ring exhibits a preferred orientation with an average tilt angle of about 64°. The experimental results showed that DOPA-thiol with amide linkage is able to self-assemble and form a layered structured film consisting of a layer of alkane chains with a gauche conformation beneath an oriented layer of DOPA.

  • 62.
    Petoral, Rodrigo Jr
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Uvdal, Kajsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Structural investigation of t-butyl carbamate-thiol chemisorbed on gold2005In: EuCheMS,2005, 2005Conference paper (Refereed)
  • 63.
    Petoral, Rodrigo Jr
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Structure of tert-butyl carbamate-terminated thiol chemisorbed to gold2005In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 109, no 33, p. 16040-16046Article in journal (Refereed)
    Abstract [en]

    Monolayers of tert-butyl carbamate-terminated thiol were formed by adsorption of the molecules onto polycrystalline gold substrate. The adsorbates were studied using techniques as X-ray photoelectron spectroscopy (XPS), near-edge X-ray absorption fine structure spectroscopy (NEXAFS), and infrared reflection−absorption spectroscopy (IRAS). The results provide the electronic structure, composition, characteristic fingerprint, and orientation of the molecular adsorbate. XPS verified that the thiolate group is chemically bonded to the gold surface and that a complete chemisorption of the molecule occurs. Elemental depth profiling by varying the excitation energy in XPS supports the angle-dependent XPS results. Both techniques showed that the tert-butyl group is oriented away from the gold surface. A nearly parallel orientation of the carbonyl group relative to the gold surface is deduced from the IRAS results. The main molecular axis is estimated to have an average tilt angle of about 38° relative to the gold surface normal on the basis of the NEXAFS results. Cyclic voltammetry indicates a less blocking capability of the adsorbates. Overall, the molecules are oriented in an upright manner with indications of presence of pinholes and/or defects possibly due to steric hindrance of the bulky tert-butyl group. This molecular system is envisioned to be of use for surface-based organic synthesis on gold substrates.

  • 64.
    Petoral, Rodrigo Jr
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    XPS and NEXAFS study of tyrosine-terminated propanethiol assembled on gold2003In: Journal of Electron Spectroscopy and Related Phenomena, ISSN 0368-2048, E-ISSN 1873-2526, Vol. 128, no 2-3, p. 159-164Article in journal (Refereed)
    Abstract [en]

    Tyrosine-terminated propanethiol (TPT), tyrosine linked to 3-mercaptopropionic acid through an amide bond, is adsorbed to gold surfaces. The adsorbates are characterized by means of X-ray photoelectron spectroscopy (XPS) and near-edge X-ray absorption fine structure spectroscopy (NEXAFS). XPS is used to investigate the chemical binding and electronic structure of the monolayer. Strong molecular binding of the tyrosine derivative on the gold surface through the sulfur atom is attained. Angle-dependent XPS results shows that TPT molecules are oriented with the sulfur atoms molecularly oriented close to the gold surface and that the phenol moiety is oriented away from the gold surface. Average orientation of the adsorbate on gold is deduced using the NEXAFS results. It shows that the main molecular axis is tilted approximately 38° relative to the Au surface normal. The ring plane of the phenol moiety exhibits a preferential orientation with an average tilt angle of the normal of the ring plane from the surface normal of about 60°.

  • 65.
    Petoral, Rodrigo Jr
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Wermelin, Karin
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Orthopaedics and Sports Medicine .
    Dahlstedt, E.
    Hellberg, J.
    Uvdal, Kajsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Adsorption of n-butyl-substituted tetrathiafulvalene dodecanethiol on gold2005In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 287, no 2, p. 388-393Article in journal (Refereed)
    Abstract [en]

    Tetrathiafulvalene (TTF) derivative substituted with two butyl- and two dodecylthiol chains is adsorbed on polycrystalline gold. The TTF-derived thiol adsorbates were characterized by ellipsometry, contact angle goniometry, infrared and X-ray photoelectron spectroscopy and cyclic voltammetry. The molecule is strongly anchored on the gold surface through the sulfur terminating the alkylthiol chains. On the average, the TTF moiety is oriented extended away from the gold surface. The topmost layer of the film containing the dibutyl chains is disordered with gauche defects. The molecule was organized with majority of the alkylthiol chains bound to the gold surface. There are indications of pinholes in the monolayer due to steric hindrance of the bulky TTF rings. The molecular systems consisting of an electroactive π-system such as TTF, are promising for thin-film field effect transistor application. © 2005 Elsevier Inc. All rights reserved.

  • 66.
    Petoral, Rodrigo Jr
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Yazdi, Gholamreza
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Lloyd-Spets, Anita
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics.
    Yakimova, Rositsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Organosilane-functionalized wide band gap semiconductor surfaces2007In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 90, no 22Article in journal (Refereed)
    Abstract [en]

    Surface functionalization of wide band gap semiconductors, SiC, ZnO, and GaN, with organosilane is reported. Formation of self-assembled monolayers of mercaptopropyltrimethoxysilane is confirmed by x-ray photoelectron spectroscopy and atomic force microscopy. The molecules are adsorbed on the surfaces through the silane groups with the free thiol groups molecularly oriented away from the surface. Moreover, chemisorption via the thiolate is observed for the ZnO surface. Immobilization of a model biomolecule to the functionalized surface is demonstrated. An amino acid derivative, i.e., phosphotyrosine derived thiol, is linked on the functionalized ZnO and GaN surfaces via formation of disulfide bridges. © 2007 American Institute of Physics.

  • 67.
    Petoral, Rodrigo Jr
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Yazdi, Gholamreza
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Vahlberg, Cecilia
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Syväjärvi, Mikael
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Lloyd Spetz, Anita
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Uvdal, Kajsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Yakimova, Rositsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Materials Science .
    Surface Functionalization of SiC for Biosensor Applications2007In: ECSCRM 2006,2006, Material Science Forum, vol 556-557: Trans Tech Publications , 2007, p. 957-Conference paper (Refereed)
  • 68.
    Petoral, Rodrigo M
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Söderlind, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Klasson, Anna
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medical Imaging, Department of Radiology in Linköping.
    Suska, Anke
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, Faculty of Science & Engineering.
    Fortin, Marc-André
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Abrikossova, Natalia
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Selegard, Linnea
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Käll, Per-Olov
    Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry. Linköping University, The Institute of Technology.
    Engström, Maria
    Linköping University, Center for Medical Image Science and Visualization (CMIV). Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Medical Imaging, Department of Radiology in Linköping.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Synthesis and Characterization of Tb3+-Doped Gd2O3 Nanocrystals: A Bifunctional Material with Combined Fluorescent Labeling and MRI Contrast Agent Properties2009In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 113, no 17, p. 6913-6920Article in journal (Refereed)
    Abstract [en]

    Ultrasmall gadolinium oxide nanoparticles doped with terbium ions were synthesized by the polyol route and characterized as a potentially bifunctional material with both fluorescent and magnetic contrast agent properties. The structural, optical, and magnetic properties of the organic-acid-capped and PEGylated Gd2O3:Tb3+ nanocrystals were studied by HR-TEM, XPS, EDX, IR, PL, and SQUID. The luminescent/fluorescent property of the particles is attributable to the Tb3+ ion located on the crystal lattice of the Gd2O3 host. The paramagnetic behavior of the particles is discussed. Pilot studies investigating the capability of the nanoparticles for fluorescent labeling of living cells and as a MRI contrast agent were also performed. Cells of two cell lines (THP-1 cells and fibroblasts) were incubated with the particles, and intracellular particle distribution was visualized by confocal microscopy. The MRI relaxivity of the PEGylated nanoparticles in water at low Gd concentration was assessed showing a higher T-1 relaxation rate compared to conventional Gd-DTPA chelates and comparable to that of undoped Gd2O3 nanoparticles.

  • 69.
    Rodner, Marius
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Sensor and Actuator Systems. Linköping University, Faculty of Science & Engineering.
    Puglisi, Donatella
    Linköping University, Department of Physics, Chemistry and Biology, Sensor and Actuator Systems. Linköping University, Faculty of Science & Engineering.
    Ekeroth, Sebastian
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics. Linköping University, Faculty of Science & Engineering.
    Helmersson, Ulf
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics. Linköping University, Faculty of Science & Engineering.
    Shtepliuk, Ivan
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Skallberg, Andreas
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Schutze, Andreas
    Saarland Univ, Germany.
    Eriksson, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Sensor and Actuator Systems. Linköping University, Faculty of Science & Engineering.
    Graphene Decorated with Iron Oxide Nanoparticles for Highly Sensitive Interaction with Volatile Organic Compounds2019In: Sensors, ISSN 1424-8220, E-ISSN 1424-8220, Vol. 19, no 4, article id 918Article in journal (Refereed)
    Abstract [en]

    Gases, such as nitrogen dioxide, formaldehyde and benzene, are toxic even at very low concentrations. However, so far there are no low-cost sensors available with sufficiently low detection limits and desired response times, which are able to detect them in the ranges relevant for air quality control. In this work, we address both, detection of small gas amounts and fast response times, using epitaxially grown graphene decorated with iron oxide nanoparticles. This hybrid surface is used as a sensing layer to detect formaldehyde and benzene at concentrations of relevance (low parts per billion). The performance enhancement was additionally validated using density functional theory calculations to see the effect of decoration on binding energies between the gas molecules and the sensor surface. Moreover, the time constants can be drastically reduced using a derivative sensor signal readout, allowing the sensor to work at detection limits and sampling rates desired for air quality monitoring applications.

  • 70.
    Rodner, Marius
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Sensor and Actuator Systems. Linköping University, Faculty of Science & Engineering.
    Puglisi, Donatella
    Linköping University, Department of Physics, Chemistry and Biology, Sensor and Actuator Systems. Linköping University, Faculty of Science & Engineering.
    Helmersson, Ulf
    Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics. Linköping University, Faculty of Science & Engineering.
    Ivanov, Ivan Gueorguiev
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Schuetze, Andreas
    Saarland University, Saarbrücken Germany.
    Eriksson, Jens
    Linköping University, Department of Physics, Chemistry and Biology, Sensor and Actuator Systems. Linköping University, Faculty of Science & Engineering.
    Iron oxide nanoparticle decorated graphene for ultra-sensitive detection of volatile organic compounds2018In: Proceedings, ISSN 2504-3900, Vol. 2, no 13, article id 985Article in journal (Refereed)
    Abstract [en]

    It has been found that two-dimensional materials, such as graphene, can be used as remarkable gas detection platforms as even minimal chemical interactions can lead to distinct changes in electrical conductivity. In this work, epitaxially grown graphene was decorated with iron oxide nanoparticles for sensor performance tuning. This hybrid surface was used as a sensing layer to detect formaldehyde and benzene at concentrations of relevance in air quality monitoring (low parts per billion). Moreover, the time constants could be drastically reduced using a derivative sensor signal readout, allowing detection at the sampling rates desired for air quality monitoring applications.

  • 71.
    Rong, Yu
    et al.
    University of Washington, WA USA .
    Wu, Changfeng
    Jilin University, Peoples R China .
    Yu, Jiangbo
    University of Washington, WA USA .
    Zhang, Xuanjun
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Ye, Fangmao
    University of Washington, WA USA .
    Zeigler, Maxwell
    University of Washington, WA USA .
    Gallina, Maria Elena
    University of Washington, WA USA .
    Wu, I-Che
    University of Washington, WA USA .
    Zhang, Yong
    University of Washington, WA USA .
    Chan, Yang-Hsiang
    University of Washington, WA USA .
    Sun, Wei
    University of Washington, WA USA .
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Chiu, Daniel T.
    University of Washington, WA USA .
    Multicolor Fluorescent Semiconducting Polymer Dots with Narrow Emissions and High Brightness2013In: ACS Nano, ISSN 1936-0851, E-ISSN 1936-086X, Vol. 7, no 1, p. 376-384Article in journal (Refereed)
    Abstract [en]

    Fluorescent semiconducting polymer dots (Pdots) have attracted great interest because of their superior characteristics as fluorescent probes, such as high fluorescence brightness, fast radiative rates, and excellent photostability. However, currently available Pdots generally exhibit broad emission spectra, which significantly limit their usefulness in many biological applications Involving multiplex detections. Here, we describe the design and development of multicolor narrow emissive Pdots based on different boron dipyrromethene (BODIPY) units. BODIPY-containing semiconducting polymers emitting at multiple wavelengths were synthesized and used as precursors for preparing the Pdots, where intraparticle energy transfer led to highly bright, narrow emissions. The emission full width at half-maximum of the resulting Pdots varies from 40 to 55 nm, which is 15-2 times narrower than those of conventional semiconducting polymer dots. BODIPY 520 Pdots were about an order of magnitude brighter than commercial Qdot 525 under identical laser excitation conditions. Fluorescence imaging and flow cytometry experiments indicate that the narrow emissions from these bright Pdots are promising for multiplexed biological detections.

  • 72.
    Sadreev, A.F.
    et al.
    Kirensky Institute of Physics, 660036, Krasnoyarsk, Russian Federation, Dept. of Phys. and Msrmt. Technology, Linkoping University, S-581 83 Linkoping, Sweden.
    Sukhunin, Y.V.
    Kirensky Institute of Physics, 660036, Krasnoyarsk, Russian Federation.
    Petoral, Rodrigo .M.
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics . Linköping University, The Institute of Technology.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics . Linköping University, The Institute of Technology.
    Ground state and phase transitions in a system of arg-cysteamines self-assembled on a Au(111) crystal surface2004In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 120, no 2, p. 954-960Article in journal (Refereed)
    Abstract [en]

    A study was conducte don the ground state for the arg-cysteamine adsorbates. As such, the ground state energy of a monolayer self-assembled on Au(111) reveals a hexagonal structure reported for long-chained alkyl thiols. It was found that the hydrogen bonds in fact increase the temperature of phase transition by 40K.

  • 73.
    Sadreev, Almas
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Sukhinin, Y.V.
    Uvdal, Kajsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Pohl, A.
    Thermal reduction of activation energy of tricyclohexylphosphine on a rhodium crystal surface2001In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 115, no 20, p. 9513-9518Article in journal (Refereed)
    Abstract [en]

    The activation energy of desorption for TCHP adsorbed on Rh(111) was calculated. Thermal atomic displacements of a semi-infinite metal of the crystal and effects of molecular rotation modes were included in the calculation. The potential versus the molecular distance to the Rh surface was taken as the Morse potential but with parameters fitted to the DFT calculations. The resulting data was analyzed in detail.

  • 74.
    Salomonsson, Anette
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics . Linköping University, The Institute of Technology.
    Petoral Jr., Rodrigo M.
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics . Linköping University, The Institute of Technology.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics . Linköping University, The Institute of Technology.
    Aulin, Christian
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Käll, Per-Olov
    Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry . Linköping University, The Institute of Technology.
    Ojamäe, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry . Linköping University, The Institute of Technology.
    Strand, Michael
    School of Technology and Design/Chemistry, Växjö University, Växjö, Sweden.
    Sanati, Mehri
    School of Technology and Design/Chemistry, Växjö University, Växjö, Sweden.
    Lloyd Spetz, Anita
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics . Linköping University, The Institute of Technology.
    Nanocrystalline Ruthenium oxide and Ruthenium in sensing applications -an experimental and theoretical study2006In: Journal of Nanoparticle Research, ISSN 1388-0764, Vol. 8, no 6, p. 899-910Article in journal (Refereed)
    Abstract [en]

    In this project, we have explored RuO2 and Ru nanoparticles (∼ ∼10 and ∼ ∼5 nm, respectively, estimated from XRD data) to be used as gate material in field effect sensor devices. The particles were synthesized by wet chemical procedure. The capacitance versus voltage characteristics of the studied capacitance shifts to a lower voltage while exposed to reducing gases. The main objectives are to improve the selectivity of the FET sensors by tailoring the dimension and surface chemistry of the nanoparticles and to improve the high temperature stability. The sensors were characterized using capacitance versus voltage measurements, at different frequencies, 500 Hz to 1 MHz, and temperatures at 100–400°C. The sensor response patterns have been found to depend on operating temperature. X-ray photoelectron spectroscopy (XPS) analyses were performed to investigate the oxidation state due to gas exposure. Quantum-chemical computations suggest that heterolytic dissociative adsorption is favored and preliminary computations regarding water formation from adsorbed hydrogen and oxygen was also performed.

  • 75.
    Savitchi, Luminita
    et al.
    Linköping University, Department of Science and Technology. Linköping University, The Institute of Technology.
    Vahlberg, Cecilia
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Petoral, Rodrigo Jr
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Mixed monolayers to promote G-protein adsorption: α2A- Adrenergic receptor-derived peptides coadsorbed with formyl-terminated oligopeptides2007In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 23, no 16, p. 8474-8479Article in journal (Refereed)
    Abstract [en]

    Pure and mixed monolayers of a synthetic peptide, GPR-i3n, derived from the third intracellular loop of the α2 adrenergic receptor and a shorter inactive oligopeptide, N-formyl-(Gly)3-(Cys) (called 3GC), were prepared on gold surfaces. The mixing ratio of the GPR-i3n and 3GC was used to control G-protein binding capability. The GPR-i3n peptide is specially designed for bovine G-protein selectivity and has been proven to have high affinity to G-proteins [Vahlberg, C.; Petoral, R. M., Jr.; Lindell, C.; Broo, K.; Uvdal, K. Langmuir 2006, 22 (17), 7260−7264]. Pure 3GC monolayers show very low protein adsorption capability. In this study, 3GC is chosen as a coadsorbent, with the aim to induce molecular conformational changes during monolayer formation to enhance G-protein adsorption. A full characterization of the mixed monolayers was done. The monolayer thickness and the mass-related surface coverage for both GPR-i3n and 3GC were investigated using radio labeling. The GPR-i3n was labeled by 125I-targeting tyrosine, and the activity was measured by using radioimmunoassay (RIA). The formation and chemical composition of GPR-i3n and 3GC monolayers were investigated using X-ray photoelectron spectroscopy, and it is shown that both GPR-i3n and 3GC bind chemically to the gold surface. The interaction between the mixed monolayers and G-proteins was investigated by means of real-time surface plasmon resonance. There is a higher protein binding capacity to the monolayer when the GPR-i3n peptide is intermixed with the 3GC coadsorbent, despite the fact that the 3GC itself has a very low G-protein binding capability. This supports a molecular reorientation at the surface, while 3GC is intermixed with GPR-i3n.

  • 76.
    Selegård, Linnéa
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Ahrén, Maria
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Brommesson, Caroline
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, The Institute of Technology.
    Söderlind, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, The Institute of Technology.
    Persson, Per. O. Å
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Bifunctional gadolinium decorated ZnO nanocrystals integrating both enhanced MR signal and bright fluorescence2013Manuscript (preprint) (Other academic)
    Abstract [en]

    Gadolinium decorated ZnO nanoparticles simultaneously possess both fluorescent and MR enhancement properties. These ZnO nanoparticles are crystalline and shielded by an amorphous gadolinium acetate matrix. Interestingly, the Gd-acetate decoration enhances the fluorescence emission of the ZnO nanoparticles. The quantum yield does increase for samples with high Gd/Zn relative ratios and these samples do also show a higher colloidal stability.

    In addition, these nanoparticles show an enhanced relaxivity value per Gd atom (r119.9mM1s-1) compared to results earlier reported both on Gd alloyed ZnO nanoparticles and pure Gd2O3 nanoparticles. This improvement is considered to be due to the close proximity of Gd atoms and surrounding water molecules. A comprehensive study of the quantum yield and the relaxivity, as a function of composition, enable us to identify the ultimate design/composition of gadolinium decorated ZnO nanoparticles for optimum fluorescence and MR enhancement properties.

  • 77.
    Selegård, Linnéa
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Khranovskyy, Volodymyr
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Söderlind, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Vahlberg, Cecilia
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Ahrén, Maria
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Käll, Per-Olov
    Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry. Linköping University, The Institute of Technology.
    Yakimova, Rositsa
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Biotinylation of ZnO Nanoparticles and Thin Films: A Two-Step Surface Functionalization Study2010In: ACS APPLIED MATERIALS and INTERFACES, ISSN 1944-8244, Vol. 2, no 7, p. 2128-2135Article in journal (Refereed)
    Abstract [en]

    This study reports ZnO nanoparticles and thin film surface modification using a two-step functionalization strategy. A small silane molecule was used to build up a stabilizing layer and for conjugation of biotin (vitamin B7), as a specific tag. Biotin was chosen because it is a well-studied bioactive molecule with high affinity for avidin. ZnO nanoparticles were synthesized by electrochemical deposition under oxidizing condition, and ZnO films were prepared by plasma-enhanced metal organic chemical vapor deposition. Both ZnO nanoparticles and ZnO thin films were surface modified by forming a (3-mercaptopropyl)trimethoxysilane (MPTS) layer followed by attachment of a biotin derivate. lodoacetyl-PEG2-biotin molecule was coupled to the thiol unit in MPTS through a substitution reaction. Powder X-ray diffraction, transmission electron microscopy, X-ray photoemission electron microscopy, atomic force microscopy. X-ray photoelectron spectroscopy, and near-edge X-ray absorption fine structure spectroscopy were used to investigate the as-synthesized and functionalized ZnO materials. The measurements showed highly crystalline materials in both cases with a ZnO nanoparticle diameter of about 5 nm and a grain size of about 45 nm for the as-grown ZnO thin films. The surface modification process resulted in coupling of silanes and biotin to both the ZnO nanoparticles and ZnO thin films. The two-step functionalization strategy has a high potential for specific targeting in bioimaging probes and for recognition studies in biosensing applications.

  • 78.
    Selegård, Linnéa
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Zakharov, Alexei
    MAX-lab, Lund University, Lund, Sweden.
    Skallberg, Andréas
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, The Institute of Technology.
    Abrikossova, Natalia
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    PEEM, LEED and PES temperature study of Eu doped Gd2O3 nanoparticles and their interactions with silicon2013Manuscript (preprint) (Other academic)
    Abstract [en]

    We report the formation of silicate and silicide by annealing of a SiOx surface, with low coverage of Eu doped Gd2O3 nanoparticles. Interestingly, the annealing temperature required for removal of native oxide from the Si substrate decreases with as much as 200 degrees in presence of the nanoparticles. XPEEM, LEEM and MEM are used to monitor the silicide/silicate formation and SiOx removal. Fragmentation of the nanoparticles is observed, and the SiOx layer is gradually removed. Eu is migrating to clean Si areas during the annealing process, while Gd is found in areas where oxide is still present. This annealing process is clearly facilitated in the presence of rare-earth based nanoparticles, where nanoparticles are suggested to function as reaction sites. Reduction of the annealing temperature of SiOx substrates is also observed in presence of pure Eu3+ and Gd3+ ions, but to lesser extent. The significant reduction of the annealing temperature of SiO by several hundred degrees, in presence of Eu doped Gd2O3 nanoparticles, is remarkable. This type of material may find applications both within optoelectronics and processing microelectronic industry.

  • 79.
    Siribbal, Shifaa M.
    et al.
    Univ Cologne, Germany.
    Schlaefer, Johannes
    Univ Cologne, Germany.
    Ilyas, Shaista
    Univ Cologne, Germany.
    Hu, Zhangjun
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Valldor, Martin
    Max Planck Inst Chem Phys Solids, Germany.
    Mathur, Sanjay
    Univ Cologne, Germany.
    Air-Stable Gadolinium Precursors for the Facile Microwave-Assisted Synthesis of Gd2O3 Nanocontrast Agents for Magnetic Resonance Imaging2018In: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 18, no 2, p. 633-641Article in journal (Refereed)
    Abstract [en]

    Using metal organic precursors in materials synthesis remains a challenge due to their high moisture susceptibility. In this work, we describe a facile methodology for the synthesis of Gd2O3-based contrast agents from two new gadolinium-based complexes. [Gd(PyTFP)(4)] (PyH) 1 (PyTFP = C8H5NOF3, Py = C5H5N) and [Gd(DMOTFP)(3)Py] 2 (DMOTFP = C8H7NO2F3) were synthesized via a classical ligand exchange reaction of [Gd{N(SiMe3)(2)}(3)] under inert conditions. As a result, X-ray diffraction analysis revealed a distorted square antiprismatic coordination and an augmented triangular prismatic arrangement of ligands around gadolinium atoms in 1 and 2, respectively. It also showed that 1 is an anionic complex of formula [Gd(PyTFP)(4)](PyH), while a neutral tris-compound, [Gd(DMOTFP)(3)Py], was obtained as a pyridine adduct in 2. Fast and reproducible microwave-assisted decomposition of 1 and 2 provided homogeneous Gd(OH)(3) nanorods at mild temperature without using any surfactant or capping reagent. As-synthesized nanorods were easily transformed into a cubic phase of Gd2O3 nanoparticles by thermal treatment under ambient conditions. The magnetic measurement showed the typical paramagnetic behavior of the Gd2O3 nanoparticles (NPs). The cytotoxicity profile demonstrates the biocompatibility and negligible toxicity of the as-synthesized nanoprobes. The suggested approach provides a new class of gadolinium-based precursors which allows facile synthesis of highly crystalline Gd2O3 NPs.

  • 80.
    Skallberg, Andreas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Brommesson, Caroline
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Imaging XPS and photoemission electron microscopy; surface chemical mapping and blood cell visualization2017In: Biointerphases, ISSN 1934-8630, E-ISSN 1559-4106, Vol. 12, no 2, article id 02C408Article in journal (Refereed)
    Abstract [en]

    Combined photoemission electron microscopy (PEEM) and imaging x-ray photoelectron spectroscopy (XPS), i.e., electron spectroscopy for chemical analysis in the nanoregion, has been used for surface characterization of bio-relevant and biological samples. In the first example, the authors prepared a gold patterned silicon substrate, stepwise surface modified by self-assembled monolayers followed by quantum dot (QDot) specific linking and investigated by means of work function mapping and elemental imaging in the submicrometer range. Spatially resolved core level images of C1s, V2p, and Y3d are obtained, which verify the selective thiol adsorption on the gold squares and specific binding of europium doped yttrium vanadate QDots on the self-assembled monolayer. The second example is platelet adhesion to Immunoglobulin G modified silicon surfaces, investigated by means of laterally resolved PEEM. Images of platelets clearly show activated cells with a morphology change including an enlarged surface area and elongated pseudopodia, with a lateral resolution of 140 nm. In the last example, neutrophils were allowed to attach to plain silicon surfaces and investigated by means of PEEM and imaging XPS. Here, the cells show a round shaped morphology, as expected. Threshold imaging with work function contrast is used to localize the area of interest, followed by elemental specific mapping on cells in the submicrometer region. Chemical shifts of C1s in photoemission are used to distinguish vital parts of the cell structure. The strong C1s (C-C) signal is achieved from the region of the cell membrane, i.e., high density of phospholipids, while C1s (C-N) and C1s (C-O) signals are obtained from the core of the cell, in good agreement with the presence of cytoplasm and deoxyribonucleic acid containing cell nucleus. The combination of PEEM and imaging XPS is shown here as a tool to deliver new insight into biological samples, i.e., a rapid sample overview is obtained based on low energy secondary electrons with work function contrast, followed by detailed studies in the narrow mode for elemental compositions based on photoemission. This study illustrates the strength of combined PEEM and XPS in the imaging mode on cell studies. (C) 2017 American Vacuum Society.

  • 81.
    Skallberg, Andreas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Bunnfors, Kalle
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Brommesson, Caroline
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Neutrophils Activated by Nanoparticles and Formation of Neutrophil Extracellular Traps: Work Function Mapping and Element Specific Imaging2019In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 91, no 21, p. 13514-13520Article in journal (Refereed)
    Abstract [en]

    Photoemission electron microscopy (PEEM) and imaging X-ray photoelectron spectroscopy (XPS) have over the years been powerful tools in classical surface physics and material sciences, and due to recent technological advances, their uses within other fields/disciplines are rapidly growing. Lately, the XPS/PEEM based elemental analysis and characterization in imaging mode, with exquisite spatial resolution and high sensitivity, has shown the potential to deliver new mechanistic insights in cell-biology/medicine. In this work, the aim was to visualize biological processes on the cellular level, with the additional dimension of topographical morphology and element specific information, mapping chemical composition and chemical states. This is hereby demonstrated by combined PEEM and imaging XPS investigation of neutrophils and their activation processes, where fluorescence microscopy commonly used in biology is used for benchmarking. Neutrophils are phagocytic cells and are vital components in the human immune system, with the fundamental role of fighting invading pathogens. They are capable of ingesting microorganisms or particles, and in order to capture and trap foreign objects, one of their strategies is to release nuclear DNA by the formation of extracellular web-like traps (NETs). Here, we report how neutrophils are triggered by controlled nanoparticle (NP) exposure. The neutrophils and NETs formation are imaged in the presence of NPs, and we report the elemental composition of single cells and the structure of NETs. Cellular uptake of nanoparticles is proven and the states just before and after NETs release are imaged, as well as visualization of the extraordinary capability for mass transport at distances 10 times or more than the size of the cell itself. This method paves the way for element specific imaging of biorelated cells on surfaces as well as nanoparticle tracking in the submicro- and nanoregions.

  • 82.
    Söderlind, Fredrik
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry. Linköping University, Faculty of Science & Engineering.
    Fortin, Marc A.
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Petoral, Rodrigo M.
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Klasson, Anna
    Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Veres, Teodor
    National Research Council of Canada .
    Engström, Maria
    Linköping University, Department of Medical and Health Sciences, Radiology. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Käll, Per-Olov
    Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry. Linköping University, Faculty of Science & Engineering.
    Colloidal synthesis and characterization of ultrasmall perovskite GdFeO3 nanocrystals2008In: Nanotechnology, ISSN 0957-4484, Vol. 19, no 8, p. 085608-Article in journal (Refereed)
    Abstract [en]

    Synthesis of very small (about 4 nm) perovskite structured gadolinium orthoferrite nanoparticles (GdFeO3) was performed by the polyol method. The material shows promising relaxivity properties and potential as a contrast agent in magnetic resonance imaging. The perovskite nanoparticles were characterized by x-ray diffraction, transmission electron microscopy, energy dispersive x-ray spectroscopy, Fourier transform infrared spectroscopy, magnetic resonance, and magnetization measurements. Upon heating in air at 800 °C for 3 h the size of the crystals increased to about 40 nm. The crystalline structure of the heat treated compound is in good agreement with perovskite GdFeO3 as the primary product. Contributions from various secondary phases were also identified, including one hitherto unknown phase with the suggested composition 'Gd3FeO6' and isostructural with Gd3GaO6. The novel 'Gd3FeO6' phase appears to be kinetically stabilized in the nano state.

  • 83.
    Söderlind, Fredrik
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Inorganic Chemistry. Linköping University, The Institute of Technology.
    Pedersen, Henrik
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, The Institute of Technology.
    Petoral, Rodrigo M.
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Käll, Per-Olov
    Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry. Linköping University, The Institute of Technology.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Synthesis and characterisation of Gd2O3 nanocrystals functionalised by organic acids2005In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 288, no 1, p. 140-148Article in journal (Refereed)
    Abstract [en]

    Nanocrystals of Gd2O3 have been prepared by various methods, using, e.g., trioctylphosphine oxide (TOPO), diethylene glycol (DEG) or glycine. The crystalline particles were of sizes 5 to 15 nm. Different carboxylic acids, e.g., oleic acid or citric acid, were adsorbed onto the surface of the particles made with DEG. IR measurements show that the molecules coordinate to the Gd2O3 surface via the carboxylate group in a bidentate or bridging manner. The organic-acid/particle complexes were characterised by XRPD, TEM, FTIR, Raman, and XPS.

  • 84.
    Söderlind, Fredrik
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Inorganic Chemistry. Linköping University, Faculty of Science & Engineering.
    Selegård, Linnea
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Nordblad, Per
    Uppsala University.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Käll, Per-Olov
    Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry. Linköping University, The Institute of Technology.
    Sol-gel synthesis and characterization of polycrystalline GdFeO3 and Gd3Fe5O12 thin films2009In: Journal of Sol-Gel Science and Technology, ISSN 0928-0707, E-ISSN 1573-4846, Vol. 49, no 2, p. 253-259Article in journal (Refereed)
    Abstract [en]

    Thin films of the perovskite and garnet structured gadolinium ferrites GdFeO3 and Gd3Fe5O12 have been synthesized by a sol-gel method, based on stoichiometric mixtures of acetyl acetone chelated Gd3+ and Fe3+ dissolved in 2-methoxy ethanol. After spin coating onto Si wafers, and heating in air at 700 degrees C for 20 h, neatly grown essentially single phase films were obtained. From X-ray photoelectron spectroscopy an iron deficiency is observed in the uppermost layer of both films, implying that the crystallites preferably end in planes rich in Gd and O but not in Fe. The films were also characterized by X-ray powder diffraction, scanning electron microscopy, infrared spectroscopy, and magnetic measurements.

  • 85.
    Tengvall, Pentti
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Kindgren, Alf
    Järrendahl, Kenneth
    Uvdal, Kajsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    CDIO-based courses in engineering biology at LiTH2005In: CDIO International Conference and Collaborators meeting,2005, 2005Conference paper (Other academic)
  • 86.
    Tian, Xiaohe
    et al.
    Anhui University, Peoples R China.
    Zhang, Qian
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering. Anhui University, Peoples R China.
    Zhang, Mingzhu
    Anhui University, Peoples R China.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Wang, Qin
    Anhui Agriculture University, Peoples R China.
    Chen, Junyang
    Anhui University, Peoples R China.
    Du, Wei
    Anhui University, Peoples R China.
    Huang, Bei
    Anhui University, Peoples R China.
    Wu, Jieying
    Anhui University, Peoples R China.
    Tian, Yupeng
    Anhui University, Peoples R China; Nanjing University, Peoples R China.
    Probe for simultaneous membrane and nucleus labeling in living cells and in vivo bioimaging using a two-photon absorption water-soluble Zn(II) terpyridine complex with a reduced pi-conjugation system2017In: Chemical Science, ISSN 2041-6520, E-ISSN 2041-6539, Vol. 8, no 1, p. 142-149Article in journal (Refereed)
    Abstract [en]

    Small, biocompatible and water-soluble molecules with high two-photon absorption (2PA) cross-section values (delta) are in high demand for specific bioimaging applications. Here, two novel terpyridine derivative ligands with donor-acceptor (D-A) (L1) and donor-pi-acceptor (D-pi-A) (L2) models, and their corresponding Zn(II) complexes are designed and characterized. It was found that the two-photon absorption cross section values (d) in the near-infrared region (NIR, about 800 nm) are significantly enhanced for complexes 1 and 2 compared to their free D-A type ligand L1, while those of complexes 3 and 4 were greatly decreased relative to their free ligand L2, thus confirming that the smaller ligand (D-A type) displays a suitable Turn-ON fluorescence pair for two-photon fluorescence microscopy (2PFM). Firstly, the potential of simultaneously labeling a live cell plasma membrane and nucleus using complex 1 is demonstrated. In addition, live larval and adult zebrafish incubated with an optimal concentration of 1 demonstrated clear brain uptake. Lastly and importantly, using such a probe to visualize the blood-brain- barrier (BBB) capillary endothelial cells and penetrate the BBB into the central nervous system (CNS) intravenously in a mouse model is also explored.

  • 87.
    Uvdal, Kajsa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Functionalized Nanoparticles for Biomedical Imaging2007In: The 6th KAST-KVA Bilateral Symposium,2007, 2007Conference paper (Other academic)
  • 88.
    Uvdal, Kajsa
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Ahrén, Maria
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Selegård, Linnéa
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Abrikossova, Natalia
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Klasson, Anna
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Radiology . Linköping University, Center for Medical Image Science and Visualization, CMIV.
    Söderlind, Fredrik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Engström, Maria
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Center for Medical Image Science and Visualization, CMIV.
    Käll, Per-Olov
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry .
    Functionalized Gd2O3 Nanoparticles to Be used for MRI Contrast Enhancement2008In: AVS,2008, 2008Conference paper (Other academic)
  • 89.
    Uvdal, Kajsa
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Ahrén, Maria
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Söderlind, Fredrik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Klasson, Anna
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Radiology . Linköping University, Center for Medical Image Science and Visualization, CMIV.
    Vahlberg, Cecilia
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Petoral, Rodrigo Jr
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Engström, Maria
    Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Clinical and Experimental Medicine, Cell Biology.
    Käll, Per-Olov
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry .
    Functionalized rare earth nanocrystals for MRI contrast enhancement2006In: e-MRS,2006, 2006Conference paper (Other academic)
    Abstract [en]

      

  • 90.
    Uvdal, Kajsa
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics . Linköping University, The Institute of Technology.
    Axelsson, Oskar
    Visualization of Biological Material by the use of Coated Contrast Agents2008Patent (Other (popular science, discussion, etc.))
    Abstract [en]

      

  • 91.
    Uvdal, Kajsa
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Ekeroth, Johan
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Konradsson, Peter
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry .
    Liedberg, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Tyrosine derivatives assembled on gold2003In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 260, no 2, p. 361-366Article in journal (Refereed)
    Abstract [en]

    Two different tyrosine derivatives, one with the OH group free and one with the OH group phosphorylated, linked to 3-mercaptopropionic acid through an amide bond are adsorbed to gold surfaces. The adsorbates are studied by means of X-ray photoelectron spectroscopy (XPS) and infrared reflection-absorption spectroscopy (IRAS). The techniques are used to investigate the coordination to the surface and the molecular orientation of adsorbates relative to the surface. Molecular surface interactions, causing chemical shifts in the core level XPS spectra of the adsorbates on gold, are investigated using multilayer films as references. Angle-dependent XPS, XPS(T), and IRAS are used to estimate molecular orientation relative to the surface. The tyrosine derivatives adsorb chemically to the surface through the sulfur atoms and highly organized monolayers are formed with the OH and the PO32- exposed to the air/vacuum interface. © 2003 Elsevier Science (USA). All rights reserved.

  • 92.
    Uvdal, Kajsa
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Engström, Maria
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Radiology .
    Gadolinium oxide nanoparticles and their utility in selective tissue imaging as well as a cell or molecular analysisPatent (Other (popular science, discussion, etc.))
  • 93.
    Uvdal, Kajsa
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Engström, Maria
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Radiology .
    Nanoscale particles made of a transition metal and/or rare earth metal compoundPatent (Other (popular science, discussion, etc.))
    Abstract [en]

       

  • 94.
    Uvdal, Kajsa
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Engström, Maria
    Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization, CMIV. Linköping University, Department of Clinical and Experimental Medicine, Cell Biology.
    Nanoscale particles made of a transition metal and/or rare earth metal compound2004Patent (Other (popular science, discussion, etc.))
    Abstract [en]

     US provinsional application

  • 95.
    Uvdal, Kajsa
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Lögdlund, M.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Dannetun, Per
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Bertilsson, L.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Stafström, Sven
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Salaneck, William R.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    MacDiarmid, A. G.
    Department of Chemistry, University of Pennsylvania, Philadelphia, USA.
    Ray, A.
    Chemistry, University of Pennsylvania, Philadelphia, USA.
    Scherr, E. M.
    Chemistry, University of Pennsylvania, Philadelphia, USA.
    Hjertberg, T.
    Department of Polymer Technology, Chalmers University, Göteborg, Sweden.
    Epstein, A. J.
    Department of Physics, The Ohio State University, Columbus, OH, USA.
    Vapor deposited polyaniline1989In: Synthetic metals, ISSN 0379-6779, E-ISSN 1879-3290, Vol. 29, no 1, p. 451-456Article in journal (Refereed)
    Abstract [en]

    We have prepared thin films of polyaniline (emeraldine base) by an open boat evaporation process. These vapor-deposited films have a higher molecular weight than expected from a vapor deposition process, indicating a post deposition chemical process. The films have optical properties very similar to, but not identical to, these of “conventional” emeraldine. After treatment with protonic acid, the films exhibit an electrical conductivity of up to about 10% of that of conventional emeraldine salt.

  • 96.
    Uvdal, Kajsa
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Petoral, Rodrigo Jr
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Björefors, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Metal ion interaction with phosphorylated tyrosine analogue monolayers on gold2006In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 110, no 46, p. 23410-23416Article in journal (Refereed)
    Abstract [en]

    Phosphorylated tyrosine analogue molecules (pTyr-PT) were assembled onto gold substrates, and the resulting monolayers were used for metal ion interaction studies. The monolayers were characterized by X-ray photoelectron spectroscopy (XPS), infrared reflection−absorption spectroscopy (IRAS), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS), both prior to and after exposure to metal ions. XPS verified the elemental composition of the molecular adsorbate and the presence of metal ions coordinated to the phosphate groups. Both the angle-dependent XPS and IRAS results were consistent with the change in the structural orientation of the pTyr-PT monolayer upon exposure to metal ions. The differential capacitance of the monolayers upon coordination of the metal ions was evaluated using EIS. These metal ions were found to significantly change the capacitance of the pTyr-PT monolayers in contrast to the nonphosphorylated tyrosine analogue (TPT). CV results showed reduced electrochemical blocking capabilities of the phosphorylated analogue monolayer when exposed to metal ions, supporting the change in the structure of the monolayer observed by XPS and IRAS. The largest change in the structure and interfacial capacitance was observed for aluminum ions, compared to calcium, magnesium, and chromium ions. This type of monolayer shows an excellent capability to coordinate metal ions and has a high potential for use as sensing layers in biochip applications to monitor the presence of metal ions.

  • 97.
    Uvdal, Kajsa
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Petoral, Rodrigo Jr
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Söderlind, Fredrik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Käll, Per-Olov
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Physical Chemistry .
    Konradsson, Peter
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry .
    Engström, Maria
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Cell Biology. Linköping University, Center for Medical Image Science and Visualization, CMIV.
    Magnetic circular X-ray dichroism of Gd2O3 nano particles2003In: AVS,2003, 2003Conference paper (Other academic)
  • 98.
    Uvdal, Kajsa
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Sadreev, Almas
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Sukhinin, Y
    Thermoactivated desorption of Tricyclohexylphosphine from rhodium2001In: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 115, p. 9513-9519Article in journal (Refereed)
  • 99.
    Uvdal, Kajsa
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Vikinge, T.P.
    Chemisorption of the dipeptide Arg-Cys on a gold surface and the selectivity of G-protein adsorption2001In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 17, no 6, p. 2008-2012Article in journal (Refereed)
    Abstract [en]

    Arginine-L-cysteine dipeptide adsorbates are used in this study as a model system for G-protein-coupled receptors (GPCRs). An arginine-containing model molecule is chosen because the GPCR a2A has been shown to include an arginine-rich region in the G-protein-binding part of the third intracellular loop, and the role of arginines by means of recognition is believed to exceed their positive charge. The dipeptide Arg-Cys is adsorbed to gold surfaces and the peptide monolayers are characterized. These peptide monolayers are then used for G-protein adsorption experiments to study the molecular interaction and binding. The molecular adsorption, orientation, and chemical binding of the peptide to the surface are studied by X-ray photoelectron spectroscopy and infrared reflection-absorption spectroscopy. A chemical shift in the S(2p) core level spectrum of the peptide adsorbate on gold shows that there is a strong molecular surface interaction consistent with a chemical binding of the peptide to the surface through the sulfur atom. With the cysteine part linked to the surface, the arginine part of the molecule is available for further adsorption processes. Monolayers of Arg-Cys, L-cysteine, and cysteamine are used for G-protein adsorption experiments. Adsorption of human serum albumin and human immunoglobulins on the same monolayers are studied for comparison. The analytical tool is surface plasmon resonance. Two different buffers are used for the adsorption studies, and the influence of buffer composition on protein adsorption is discussed.

  • 100.
    Vahlberg, Cecilia
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics . Linköping University, The Institute of Technology.
    Linares, Mathieu
    Linköping University, Department of Physics, Chemistry and Biology, Computational Physics . Linköping University, The Institute of Technology.
    Norman, Patrick
    Linköping University, Department of Physics, Chemistry and Biology, Computational Physics . Linköping University, The Institute of Technology.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics . Linköping University, The Institute of Technology.
    Phenylboronic ester- and Phenylboronic acid-terminated alkanethiols on Gold SurfacesManuscript (preprint) (Other academic)
    Abstract [en]

    In this work, it is shown that well-organized monolayer of phenylboronic ester-terminated thiol (BOR-Capped) on gold surfaces can be prepared. Our results also show that the BORCapped molecular system can be cleaved directly on the surface, resulting in an unprotected BOR-Uncapped monolayer with the boronic acid functional groups available for dopamine coordination. The monolayers of BOR-Capped and BOR-Uncapped were characterized using infrared spectroscopy, near edge X-ray absorption fine structure spectroscopy, X-ray photoelectron spectroscopy, ellipsometry and contact angle goniometry. The X-ray photoelectron spectroscopy results showed that both BOR-Capped and BOR-Uncapped are chemically linked to the gold substrate. According to the infrared spectroscopy results, the main component of the C=O vibrational mode present in the amide moiety is perpendicular oriented relative to the gold surface normal for the BOR-Capped molecular system. The near edge X-ray absorption fine structure spectroscopy resonance peak located at approximately 285 eV, assigned to π* transitions, was used to estimate the average tilt angle of the vector parallel to the π* orbitals of the aromatic ring relative to the gold surface normal. The average tilt angle is estimated to be approximately 63º for BOR-Capped monolayer on gold surfaces. The aromatic ring of the BOR-Uncapped molecule has a more tilted orientation compared to BOR-Capped. The experimental infrared spectroscopy and near edge X-ray absorption fine structure spectroscopy results were supported with theoretical modeling including calculations of vibrational modes and of excitation processes.

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