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  • 51.
    Arteca, GA
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    Tapia, O
    Relative measure of geometrical entanglement to study folding-unfolding transitions. Application to analysis of molecular dynamics trajectories of proteins in vacuo2000In: INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, ISSN 0020-7608, Vol. 80, no 4-5, p. 848-855Article in journal (Refereed)
    Abstract [en]

    In this work, we characterize and compare folding features in protein conformations. A three-dimensional fold is quantified by a geometrical measure of chain entanglement derived from the probability distribution of projected bond-bond crossings (or "over

  • 52.
    Arteca, GA
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    Tapia, O
    Structural transitions in neutral and charged proteins in vacuo2001In: JOURNAL OF MOLECULAR GRAPHICS & MODELLING, ISSN 1093-3263, Vol. 19, no 1, p. 102-118Article in journal (Refereed)
    Abstract [en]

    In vacuo proteins provide a simple laboratory to explore the roles of sequence, temperature, charge state, and initial configuration in protein folding. Moreover, by the very absence of solvent, the study of anhydrous proteins in vacuo will also help us t

  • 53.
    Arteca, GA
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    Velazquez, I
    Technology, Department of Materials Science.
    Reimann, CT
    Tapia, O
    Molecular shape analysis of simulated in vacuo unfolding of charged lysozyme: transitions in chain entanglement and anisometry2000In: CHEMICAL PHYSICS LETTERS, ISSN 0009-2614, Vol. 327, no 3-4, p. 245-252Article in journal (Refereed)
    Abstract [en]

    We present a sensitive analysis technique to explore the configurational space of non-stationary systems. With it, we discuss the pattern of large-scale molecular shape transitions observed during the computer-simulated unfolding of charged in vacuo lysoz

  • 54.
    Arteca, GA
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    Velazquez, I
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    Reimann, CT
    Uppsala University.
    Tapia, O
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    Unfolded in vacuo lysozyme folds into native, quasinative, and compact structures1999In: PHYSICAL REVIEW E, ISSN 1063-651X, Vol. 59, no 5, p. 5981-5986Article in journal (Refereed)
    Abstract [en]

    We show that the relaxation dynamics of unfolded in vacuo lysozyme is not random. Analyses of molecular dynamics trajectories in a convenient space of molecular shape descriptors reveal a "favored" pattern of transitions leading to stable conformations. T

  • 55.
    Arteca, GA
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    Velazquez, I
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    Reimann, CT
    Uppsala University.
    Tapia, O
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    Variations in chain compactness and topological complexity uncover folding processes in the relaxation dynamics of unfolded in vacuo lysozyme1999In: JOURNAL OF CHEMICAL PHYSICS, ISSN 0021-9606, Vol. 111, no 10, p. 4774-4779Article in journal (Other academic)
    Abstract [en]

    Chain collapse and the formation of a near-native tertiary structure are believed to be two key features controlling the progress of a protein folding transition. In this work, we study the interrelation between these two properties along computer-simulat

  • 56.
    Arteca, Gustavo A.
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    Paulino, M.
    Reimann, C.T.
    Tapia, O.
    Relaxation dynamics of biopolymers seeded with unfolded lysozyme transients in vacuo. The role of primary sequence in protein folding2000In: Phys. Chem. Chem. Phys., no 2, p. 5259-5267Article in journal (Refereed)
  • 57.
    Arteca, Gustavo A.
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    Reimann, C.T.
    Tapia, O.
    Proteins in vacuo: Denaturing and folding mechanisms studied with computersimulated molecular dynamics2001In: Mass Spectrometry Reviews, Vol. 20, p. 402-422Article in journal (Refereed)
  • 58.
    Arteca, Gustavo A.
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    Tapia, O.
    Protein denaturation in vacuo: Mechanism for centrifugal unfolding of neutral lysozyme2001In: Journal of Chemical Physics, Vol. 115, no 22, p. 10557-10565Article in journal (Refereed)
  • 59.
    Arteca, Gustavo A.
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry. Department of Physical and Analytical Chemistry, Physical Chemistry I.
    Tapia, Orlando
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry. Department of Physical and Analytical Chemistry, Physical Chemistry I.
    A quantum theory of chemical processes and reaction rates based on diabatic electronic functions coupled in an external field.2005In: Journal of Matematical Chemistry, Vol. 37, no 4, p. 389-408Article in journal (Refereed)
  • 60.
    Arteca, Gustavo A.
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    Tapia, Orlando
    A simulation protocol to study proteins in vacuo. Controlled re-folding and re-unfolding transitions.2002In: Chemical Physical Letters, Vol. 365, p. 148-156Article in journal (Refereed)
  • 61. Arteca, Gustavo A.
    et al.
    Tapia, Orlando
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    A three-state model for electronic transitions represented in a generalized diabatic approach2004In: Journal of Mathematical Chemistry, Vol. 35, no 3, p. 159-174Article in journal (Refereed)
  • 62.
    Arteca, Gustavo A.
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    Tapia, Orlando
    Protein denaturation in vacuo: intrinsic unfolding pathways associated with the native tertiary structure of lysozyme2003In: Molecular Physics, Vol. 101, no 10, p. 2743-2753Article in journal (Refereed)
  • 63.
    Arteca, Gustavo A.
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    Veluri, Kalyani
    Tapia, Orlando
    Pathways for folding and re-unfolding transitions in denaturated conformations of anhydrous proteins2003In: Chemical Physics Letters, Vol. 370, p. 555-562Article in journal (Refereed)
  • 64. Asakawa, Tsuyoshi
    et al.
    Ishino, Shouhei
    Hansson, Per
    Uppsala University, Medicinska vetenskapsområdet, Faculty of Pharmacy, Department of Pharmacy. Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical and Analytical Chemistry, Physical Chemistry I.
    Almgren, Mats
    Department of Physical Chemistry. Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical and Analytical Chemistry, Physical Chemistry I.
    Ohta, Akio
    Miyagishi, Shigeyoshi
    Appearance of pure fluorocarbon micelles surveyed by fluorescence quenching of amphiphilic quinoline derivatives in fluorocarbon and hydrocarbon surfactant mixtures.2004In: Langmuir, ISSN 0743-7463, Vol. 20, no 17, p. 6998-7003Article in journal (Refereed)
  • 65.
    BALES, Barney L
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    ALMGREN, Mats
    FLUORESCENCE QUENCHING OF PYRENE BY COPPER(II) IN SODIUM DODECYL-SULFATE MICELLES - EFFECT OF MICELLE SIZE AS CONTROLLED BY SURFACTANT CONCENTRATION1995In: JOURNAL OF PHYSICAL CHEMISTRY, ISSN 0022-3654, Vol. 99, no 41, p. 15153-15162Article in journal (Refereed)
    Abstract [en]

    The aggregation numbers of sodium dodecyl sulfate (SDS) micelles and the fluorescence quenching constants, k(q), of pyrene by CU2+ have been measured as a function of SDS concentration from 25 to 200 mM. The results confirm an empirical observation made b

  • 66.
    Bales, BL
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    Shahin, A
    Lindblad, C
    Almgren, M
    Time-resolved fluorescence quenching and electron paramagnetic resonance studies of the hydration of lithium dodecyl sulfate micelles2000In: JOURNAL OF PHYSICAL CHEMISTRY B, ISSN 1089-5647, Vol. 104, no 2, p. 256-263Article in journal (Refereed)
    Abstract [en]

    A spin-probe method to study the surface hydration of sodium dodecyl sulfate (SDS) micelles (Bales, B. L.; Messina, L.; Vidal, A.; Peric, M.; Nascimento, O. R. J. Phys. Chem. 1998, 102, 10347; referred to as I) is applied to lithium dodecyl sulfate (LiDS)

  • 67.
    Barreleiro, P C A
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Olofsson, G
    Brown, W
    Edwards, K
    Bonassi, N M
    Feitosa, E
    Interaction of Octaethylene Glycol n-Dodecyl Monoether with Dioctadecyldimethylammonium Bromide and Chloride Vesicles2002In: Langmuir, Vol. 18, p. 1024-1029Article in journal (Refereed)
  • 68.
    Barzykin, Alexander V
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    Almgren, Mats
    On the distribution of surfactants among mixed micelles1996In: LANGMUIR, ISSN 0743-7463, Vol. 12, no 20, p. 4672-4680Article in journal (Refereed)
    Abstract [en]

    Composition distributions of mixed micelles are analyzed using basic principles of classical statistical mechanics with special emphasis on potential application to fluorescence quenching experiments in such systems. The problem is formulated as a lattice

  • 69. Basanez, G
    et al.
    RuizArguello, MB
    Alonso, A
    Goni, FM
    Karlsson, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Edwards, Katarina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Morphological changes induced by phospholipase C and by sphingomyelinase on large unilamellar vesicles: a cryo-transmission electron microscopy study of liposome fusion.1997In: Biophysical Journal, ISSN 0006-3495, E-ISSN 1542-0086, Vol. 72, no 6, p. 2630-2637Article in journal (Refereed)
    Abstract [en]

    Cryo-transmission electron microscopy has been applied to the study of the changes induced by phospholipase C on large unilamellar vesicles containing phosphatidylcholine, as well as to the action of sphingomyelinase on vesicles containing sphingomyelin. In both cases vesicle aggregation occurs as the earliest detectable phenomenon; later, each system behaves differently. Phospholipase C induces vesicle fusion through an intermediate consisting of aggregated and closely packed vesicles (the ''honeycomb structure'') that finally transforms into large spherical vesicles. The same honeycomb structure is also observed in the absence of enzyme when diacylglycerols are mixed with the other lipids in organic solution, before hydration. In this case the sample then evolves toward a cubic phase. The fact that the same honeycomb intermediate can lead to vesicle fusion (with enzyme-generated diacylglycerol) or to a cubic phase (when diacylglycerol is premixed with the lipids) is taken in support of the hypothesis according to which a highly curved lipid structure (''stalk'') would act as a structural intermediate in membrane fusion, Sphingomyelinase produces complete leakage of vesicle aqueous contents and an increase in size of about one-third of the vesicles. A mechanism of vesicle opening and reassembling is proposed in this case.

  • 70.
    Bastardo, L.
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    Claesson, P.
    Brown, W.
    Interactions between Mucin and Alkyl Sodium Sulfates in Solution. A Light Scattering Study2002In: Langmuir, Vol. 18, p. 3848-3853Article in journal (Refereed)
  • 71.
    Bauer, C
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    Jacques, P
    Kalt, A
    Photooxidation of an azo dye induced by visible light incident on the surface of TiO22001In: JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY, ISSN 1010-6030, Vol. 140, no 1, p. 87-92Article in journal (Refereed)
    Abstract [en]

    Oxidation of Acid Orange 7 (AO7) induced by visible light on TiO2 surfaces has been probed by FT-IR spectroscopy for identification and kinetic studies of degradation products. The tautomerism has been considered for this type of azo dye. The hydrazone fo

  • 72.
    Bauer, Christophe
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Boschloo, Gerrit
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Mukhtar, Emad
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Electron injection and recombination in Ru(dcbpy)(2)(NCS)(2) sensitized nanostructured ZnO2001In: JOURNAL OF PHYSICAL CHEMISTRY B, ISSN 1089-5647, Vol. 105, no 24, p. 5585-5588Article in journal (Refereed)
    Abstract [en]

    The dynamics of electron-transfer processes between bis(tetrabutylammonium) cis-bis(thiocyanato)bis(2,2'-bypiridine-4,4'-dicarboxylato)ruthenium(II) (called N719) and nanostructured ZnO films have been investigated by femtosecond and nanosecond spectrosco

  • 73.
    Bauer, Christophe
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Boschloo, Gerrit
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Mukhtar, Emad
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Interfacial Elevtron-Transfer Dynamics in Ru(tcterpy)(NCS)3-Sensiitized TiO2 Nanocrystalline Solar Cells2002In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 106, p. 12693-12704Article in journal (Refereed)
    Abstract [en]

    The anchoring of the ruthenium dye {(C4H9)4N}[Ru(Htcterpy)(NCS)3] (with tcterpy = 4,4‘,4‘‘-tricarboxy-2,2‘:6‘,2‘‘-terpyridine), the so-called black dye, onto nanocrystalline TiO2 films has been characterized by UV−vis and FT-IR spectroscopies. FT-IR spectroscopy data suggest that dye molecules are bound to the surface by a bidentate binuclear coordination mode. The interfacial electron-transfer (ET) dynamics has been investigated by femtosecond pump−probe transient absorption spectroscopy and nanosecond laser flash photolysis. The electron-injection process from the dye excited state into the TiO2 conduction band is biexponential with a fast component (200 ± 50 fs) and a slow component (20 ps). These two components can be attributed to the electron injection from the initially formed and the relaxed dye excited states, respectively. Nanosecond kinetic data suggest the existence of two distinguishable regimes (I and II) for the rates of reactions between injected electrons and oxidized dye molecules or oxidized redox species (D+ or I2•-). The frontier between these two regimes is defined by the number of injected electrons per particle (Ne), which was determined to be about 1. The present kinetic study was undertaken within regime I (Ne > 1). Under these conditions, the back-electron-transfer kinetics is comparable to that in systems with other ruthenium complexes adsorbed onto TiO2. The reduction of oxidized dye molecules by iodide results in the formation of I2•- on a very fast time scale (<20 ns). Within regime I, the decay of I2•- occurs in 100 ns via reaction with injected electrons (I2•- + e- → 2I-). In regime II (Ne ≤ 1), which corresponds to the normal operating conditions of dye-sensitized solar cells, the decay of I2•- is very slow and likely occurs via the dismutation reaction (2I2•-→ I- + I3-). Our results predict that, under high light intensity (Ne > 1), the quantum efficiency losses in dye-sensitized solar cells will be important because of the dramatic acceleration of the reaction between I2•- and injected electrons. Mechanisms for the ET reactions involving injected electrons are proposed. The relevance of the present kinetic studies for dye-sensitized nanocrystalline solar cells is discussed.

  • 74.
    Bauer, Christophe
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry. Department of Physical and Analytical Chemistry, Physical Chemistry I.
    Boschloo, Gerrit
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry. Department of Physical and Analytical Chemistry, Physical Chemistry I.
    Mukhtar, Emad
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry. Department of Physical and Analytical Chemistry, Physical Chemistry I.
    Hagfeldt, Anders
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry. Department of Physical and Analytical Chemistry, Physical Chemistry I.
    Ultrafast relaxation dynamics of charge carriers relaxation in ZnO nanocrystalline thin films2004In: Chemical Physics Letters, Vol. 387, no 1-3, p. 176-181Article in journal (Refereed)
  • 75.
    Bauer, Christophe
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Boschloo, Gerrit
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Mukhtar, Emad
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Ultrafast studies of electron injection in Ru dye sensitized SnO2 nanocrystalline thin film2002In: International Journal of Photoenergy, Vol. 4, p. 17-20Article in journal (Refereed)
  • 76.
    Beermann, Niclas
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    Charge Transport Properties in Nanostructured Electrodes of Metal Oxides2002Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In the last decade research in the field of nanostructured metal oxide thin film electrodes for various applications, e.g., solar cells and hydrogen production, has been of great interest. In this thesis, interfacial and bulk electrochemical properties and charge transport properties of nanostructured thin films have been investigated. Studies of the dependence on such properties on the morphology and chemical composition of the nanocrystalline metal oxide particles are reported.

    Different techniques were used to manufacture the thin film electrodes, e.g., sputtering, forced hydrolysis and a compressing method. The resulting films were investigated using time resolved photocurrent measurements and steady state solar cell measurements.

    Initial studies were performed with nanorods of iron(III)oxide as a semiconductor material for both photoelectrochemical solar energy conversion and splitting of water. Incident photon-to-current conversion efficiencies reached values that are about 7 and 100 times higher, depending on illumination direction, compared to spherical particles. In the same spirit, investigations on sputtered TiO2 material exhibiting columnar structure with a very large internal surface area were performed. Compared to colloidally prepared films, where the electron transport is driven by diffusion, the transport in the sputtered films is in addition driven by an electric field.

    Two combinations of incorporated TiO2 (Nb:TiO2 and Zr:TiO2) were investigated. Recordings from time resolved photocurrent measurements showed that the charge transport was slower for electrodes containing Zr and Nb compared to pure TiO2 sample, probably due to additional trap states. However, an increase in the overall light-to-electric-conversion efficiency was observed for a Zr content of 1–2 mol% compared to pure TiO2.

  • 77.
    Beermann, Niclas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Boschloo, Gerrit
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Trapping of electrons in nanostructured TiO2 studied by photocurrent transients2002In: Journal of Photochemistry and Photobiology A: Chemistry, Vol. 152, p. 213-218Article in journal (Refereed)
  • 78.
    Beermann, Niclas
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Vayssieres, L
    Lindquist, Sten-Eric
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Photoelectrochemical studies of oriented nanorod thin films of hematite2000In: JOURNAL OF THE ELECTROCHEMICAL SOCIETY, ISSN 0013-4651, Vol. 147, no 7, p. 2456-2461Article in journal (Refereed)
    Abstract [en]

    Thin films consisting of nanorods of hematite (alpha-Fe2O3) with controlled orientation onto transparent conductive glass substrates have been tested as photoelectrochemical cells. These films allow a more efficient transport and collection of photogenera

  • 79.
    Benkö, Gabor
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Skårman, Björn
    Wallenberg, Reine
    Hagfeldt, Anders
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Sundström, Villy
    Yartsev, Arkady P.
    Particle Size and Crystallinity Dependent Electron Injection in Flourescein 27-Sensitized TiO2 Films2003In: Journal of Physical Chemistry B, Vol. 107, p. 1370-1375Article in journal (Refereed)
  • 80.
    Berg, KE
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    Tran, A
    Raymond, MK
    Abrahamsson, M
    Wolny, J
    Redon, S
    Andersson, M
    Sun, LC
    Styring, S
    Hammarstrom, L
    Toftlund, H
    Akermark, B
    Covalently linked ruthenium(II)-manganese(II) complexes: Distance dependence of quenching and electron transfer2001In: EUROPEAN JOURNAL OF INORGANIC CHEMISTRY, ISSN 1434-1948, no 4, p. 1019-1029Article in journal (Refereed)
    Abstract [en]

    Continuing our development of artificial models for photosystem II in green plants, a series of compounds have been prepared in which a RU(bpy)(3)(2+) photosensitizer is covalently Linked to a manganese(II) electron donor. In addition to a trispicolylamin

  • 81.
    Berggren, G.
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry. Department of Photochemistry and Molecular Science, Molecular Biomimetics. Avdelningen för molekylär biomimetik.
    Anderlund, M.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry. Department of Photochemistry and Molecular Science, Molecular Biomimetics. Avdelningen för molekylär biomimetik.
    Magnuson, A.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry. Department of Photochemistry and Molecular Science, Molecular Biomimetics. Avdelningen för molekylär biomimetik.
    Åkermark, B.
    Eriksson, L.
    Sodium [1,2-bis(2-methyl-2-oxopropanamido)-benzene](tetrahydrofuran) manganese(III) methanol solvate2005In: Acta Crystallographica Section E-Structure Reports Online, Vol. 61, p. M1169-Article in journal (Refereed)
  • 82.
    Berglund Baudin, Helena
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    Electron and Energy Transfer in Supramolecular Complexes Designed for Artificial Photosynthesis2001Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In the society of today the need for alternative energy sources is increasing. The construction of artificial devices for the conversion of sunlight into electricity or fuel seems very attractive from an environmental point of view, since these devices are based on processes that does not necessarily generate any harmful biproducts. In the oxygen evolving photosynthetic process highly efficient energy and electron transfer reactions are responsible for the conversion of the sunlight into chemically stored energy and if the same principles can be used in an artificial device, the only electron supply required, is water.

    This thesis describes energy and electron transfer reactions in supramolecular complexes where the reactions are intended to mimic the basic steps in the photosynthetic process. All complexes are based on ruthenium(II)-trisbipyridine as photosensitizer, that is covalently linked to electron donors or electron or energy acceptors. The photochemical reactions were studied with time resolved transient absorption and emission measurements. In the complexes that mimic the donor side of Photosystem II, where a manganese cluster together with tyrosine catalyses the oxidation of water, intramolecular electron transfer was found to occur from Mn(II) or tyrosine to photo-oxidized Ru(III). Studies of a series of Ru(II)-Mn(II) complexes gave information of the quenching of the Ru(II) excited state by the coordinated Mn(II), which is important for the development of multi-nuclear Ru(II)-Mn complexes. In the supramolecular triad, PTZ-Ru2+-Q, the charge separated state, PTZ+●-Ru2+-Q-●, was rapidly formed, and further development where a second electron acceptor is linked to quinone is planned. Ultra fast energy transfer τ<200 fs), was obtained between ruthenium(II) and osmium(II) in a small artificial antenna fragment. Fast and efficient energy transfer is important in larger antennas or photonic wires where a rapid energy transfer is desired over a large distance.

  • 83.
    Berglund Baudin, Helena
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    Davidsson, Jan
    Serroni, Scolastica
    Juris, Alberto
    Balzani, Vincenzo
    Campagna, Sebastiano
    Hammarström, Leif
    Ultrafast Energy Transfer in Binuclear Ruthenium-Osmium Complexes as Models for Light-harvesting Antennas2002In: Journal of Physical Chemistry A, Vol. 106, p. 4312-4319Article in journal (Refereed)
  • 84.
    Berglund-Baudin, Helena
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    Sun, LC
    Davidov, R
    Sundahl, M
    Styring, Stenbjörn
    Akermark, Björn
    Almgren, Mats
    Hammarstrom, Leif
    Intramolecular electron transfer from manganese(II) coordinatively linked to a photogenerated Ru(III)-polypyridine complex: A kinetic analysis1998In: JOURNAL OF PHYSICAL CHEMISTRY A, ISSN 1089-5639, Vol. 102, no 15, p. 2512-2518Article in journal (Refereed)
    Abstract [en]

    For further investigations in the field of artificial photosynthesis, a model compound, 1, has been developed to mimic the electron-transfer steps from the manganese cluster to P-680(+) in photosystem II. In this model compound the photosensitizer rutheni

  • 85.
    Bergstrand, Nill
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    Liposomes for Drug Delivery: from Physico-chemical Studies to Applications2003Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Physico-chemical characterisation of structure and stability of liposomes intended for drug delivery is the central issue in this thesis. In addition, targeted liposomes to be used in boron neutron capture therapy (BNCT) were developed.

    Lysolipids and fatty acids are products formed upon hydrolysis of PC-lipids. The aggregate structure formed upon mixing lysolipids, fatty acids and EPC were characterised by means of cryo-TEM. A relatively monodisperse population of unilamellar liposomes was detected in mixtures containing equimolar concentration of the three components.

    The interactions between alternative steric stabilisers (PEO-PPO-PEO copolymers) and conventional PC-and pH-sensitive PE-liposomes were investigated. Whereas the PE-liposomes could be stabilised by the PEO-PPO-PEO copolymers, the PC-liposomes showed an enhanced permeability concomitant with the PEO-PPO-PEO adsorption.

    Permeability effects induced by different PEG-stabilisers on EPC liposomes were shown to be dependent on the length of the PEG chain but also on the linkage used to connect the PEG polymer with the hydrophobic membrane anchor.

    An efficient drug delivery requires, in most cases, an accumulation of the drug in the cell cytoplasm. The mechanism behind cytosolic drug delivery from pH-sensitive liposomes was investigated. The results suggest that a destabilisation of the endosome membrane, due to an incorporation of non-lamellar forming lipids, may allow the drug to be released.

    Furthermore, sterically stabilised liposomes intended for targeted BNCT have been characterised and optimised concerning loading and retention of boronated drugs.

    List of papers
    1. Aggregate structure in dilute aqueous dispersions of phospholipids, fatty acids and lysophospholipids
    Open this publication in new window or tab >>Aggregate structure in dilute aqueous dispersions of phospholipids, fatty acids and lysophospholipids
    2001 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 17, no 11, p. 3245-3253Article in journal (Refereed) Published
    Abstract [en]

    Cryo-transmission electron microscopy (cryo-TEM) was employed to investigate the aggregate structure in dilute aqueous dispersions of egg-phosphatidylcholine (EPC), oleic acid (OA), and the lysophospholipid monooleoylphosphatidylcholine (MOPC). At physiological pH and salt concentration, a relatively monodisperse population of unilamellar liposomes was detected in mixtures containing equimolar concentrations of the three components. Threadlike micelles constituted the dominant aggregate structure in samples containing high concentrations of MOPC. Excess fatty acid forced, on the other hand, the system toward structures with net negative curvature. In the absence of phospholipid, cryo-TEM revealed bilayer fragments in coexistence with threadlike micelles in mixtures containing the same molar amount of MOPC and OA. External addition of MOPC to preformed EPC liposomes gave rise to a concentration dependent evolution of intermediate structures, including open liposomes and bilayer fragments. The structural rearrangements were found to be slow and permitted visualization of a number of interesting transition structures. In addition to the structural studies, static and time-resolved fluorescence measurements were employed to determine some fundamental parameters for MOPC micelles. The results indicate a critical micelle concentration of close to 5 μM and an aggregation number of approximately 142.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:uu:diva-90315 (URN)10.1021/la010020u (DOI)
    Available from: 2003-04-30 Created: 2003-04-30 Last updated: 2017-12-14Bibliographically approved
    2. Adsorption of a PEO-PPO-PEO triblock copolymer on small unilamellar vesicles: equilibrium and kinetic properties and correlation with membrane permeability
    Open this publication in new window or tab >>Adsorption of a PEO-PPO-PEO triblock copolymer on small unilamellar vesicles: equilibrium and kinetic properties and correlation with membrane permeability
    Show others...
    2001 (English)In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 17, no 13, p. 3902-3911Article in journal (Refereed) Published
    Abstract [en]

    The adsorption of the triblock copolymer F127, poly(ethylene oxide)−poly(propylene oxide)−poly(ethylene oxide), EO98PO67EO98, onto immobilized small unilamellar vesicles (SUVs) of egg phosphatidylcholine (EPC) has been studied by means of a quartz crystal microbalance (QCM). With this technique we first show that SUVs of EPC adsorb on gold to form a monolayer of vesicles. This supported monolayer of vesicles was then used to follow the adsorption of the F127 polymer onto the lipid membrane surface. The adsorption of F127 was found to be a rapid process, and the measured polymer binding isotherm was fitted to a Freundlich type of isotherm. The maximum, or plateau, adsorbed amount was determined to be of a magnitude similar to that found for adsorption of F127 on hydrophobic surfaces. Furthermore, the desorption of the triblock copolymers from the membrane surface was followed after rinsing the SUV monolayer with pure buffer. It was found that the desorption process displayed essentially the same rapid kinetics as the adsorption process, indicating a weak interaction between the polymers and the lipid membrane. The determined polymer binding isotherm was used to correlate the adsorbed amount of polymer with the polymer-induced leakage of carboxy fluorescein (CF) from the SUVs. It was found that the membrane permeability was increased severalfold already at low surface coverage and that the maximum magnitude of the CF release rate was obtained at, or close to, F127 concentrations giving rise to the maximum adsorbed amount of polymer. In addition, the increased membrane permeability induced by the triblock copolymers was compared with the effect of adding a conventional ethylene oxide (EO) surfactant, Triton X-100, to the SUVs. The result emphasizes the dramatic effect of F127 on the bilayer permeability.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:uu:diva-90316 (URN)10.1021/la0101245 (DOI)
    Available from: 2003-04-30 Created: 2003-04-30 Last updated: 2017-12-14Bibliographically approved
    3. Effects caused by PEO-PPO-PEO triblock copolymers on structure and stability of liposomal DOPE dispersions.
    Open this publication in new window or tab >>Effects caused by PEO-PPO-PEO triblock copolymers on structure and stability of liposomal DOPE dispersions.
    (English)Article in journal (Refereed) Submitted
    Identifiers
    urn:nbn:se:uu:diva-90317 (URN)
    Available from: 2003-04-30 Created: 2003-04-30 Last updated: 2011-03-21
    4. Linkage identity is a major factor determining the effect of PEGylated surfactants, on permeability in phosphatidylcholine liposomes.
    Open this publication in new window or tab >>Linkage identity is a major factor determining the effect of PEGylated surfactants, on permeability in phosphatidylcholine liposomes.
    In: Article in journal (Refereed) Submitted
    Identifiers
    urn:nbn:se:uu:diva-90318 (URN)
    Available from: 2003-04-30 Created: 2003-04-30 Last updated: 2011-03-21
    5. Interaction between pH-sensitive liposomes and model membranes
    Open this publication in new window or tab >>Interaction between pH-sensitive liposomes and model membranes
    Show others...
    2003 (English)In: Biophysical Chemistry, ISSN 0301-4622, E-ISSN 1873-4200, Vol. 104, no 1, p. 361-379Article in journal (Refereed) Published
    Abstract [en]

    The structure and dynamics of two different pH-sensitive liposome systems were investigated by means of cryo-transmission electron microscopy and different photophysical techniques. Both systems consisted of dioleoylphosphatidylethanolamine (DOPE) and contained either oleic acid (OA) or a novel acid-labile polyethylene glycol-conjugated lipid (DHCho-MPEG5000) as stabiliser. Proton induced leakage, lipid mixing and structural changes were studied in the absence and presence of EPC liposomes, as well as in the presence of liposomes designed to model the endosome membrane. Neither DHCho-MPEG5000- nor OA-stabilised liposomes showed any tendency for fusion with pure EPC liposomes or endosome-like liposomes composed of EPC/DOPE/SM/Cho (40/20/6/34 mol.%). Our investigations showed, however, that incorporation of lipids from the pH-sensitive liposomes into the endosome membrane may lead to increased permeability and formation of non-lamellar structures. Taken together the results suggest that the observed ability of DOPE-containing liposomes to mediate cytoplasmic delivery of hydrophilic molecules cannot be explained by a mechanism based on a direct, and non-leaky, fusion between the liposome and endosome membranes. A mechanism involving destabilisation of the endosome membrane due to incorporation of DOPE, seems more plausible.

    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:uu:diva-90319 (URN)10.1016/S0301-4622(03)00011-5 (DOI)12834854 (PubMedID)
    Available from: 2003-04-30 Created: 2003-04-30 Last updated: 2017-12-14Bibliographically approved
    6. Optimization of drug loading procedures and characterization of liposomal formulations of two novel agents intended for Boron Neutron Capture Therapy (BNCT)
    Open this publication in new window or tab >>Optimization of drug loading procedures and characterization of liposomal formulations of two novel agents intended for Boron Neutron Capture Therapy (BNCT)
    1999 (English)In: Journal of liposome research, ISSN 0898-2104, E-ISSN 1532-2394, Vol. 9, no 1, p. 53-79Article in journal (Refereed) Published
    Abstract [en]

    The characterization of two liposomal formulations of boronated DNA-interacting agents has been performed. It is shown that the two boronated drugs, WSA-Water Soluble Acridine and WSP-Water Soluble Phenantridine, can be encapsulated within unilamellar sterically stabilized liposomes with high drug-to-lipid ratios (up to 0.50:1 (mol:mol)), using transmembrane pH gradients. The steric stabilization of the liposomes was accomplished by the addition of DSPE-PEG(2000) (PEG-lipid) to DSPC/Cho lipid mixtures and the composition used was DSPC:Cho:DSPE-PEG 55:40:5 (mol%). The loading of the drugs resulted in drug precipitation in the liposomal aqueous core as observed by cryo-transmission electron microscopy (c-TEM). Moreover, it is shown that when pH gradients across the bilayer were used for remote loading of WSP or when ammonium sulfate gradients were used for remote loading of WSA, the formation of small bilayer fragments (discs) was induced. We present compelling evidence that the formation of discs is a consequence of precipitate growth in the liposomal interior. The precipitate growth causes some of the liposomes to rupture resulting in the above mentioned disc-formation and a substantial decrease in trapping efficiency. The in vitro stability of the drug loaded liposomes was excellent, both in buffer and in 25% human serum. For most of the formulations, the release of the drugs was below or around 10% after 24 hours at 37 degrees C. Furthermore, the influence of initial internal pH and internal buffering capacity on release properties of WSA and WSP were investigated. It is shown that the release profiles of the drugs can be controlled, to a large extent, by varying the composition of the internal liposomal aqueous phase.

    Keywords
    BNCT, liposome, bilayer discs, drug loading, drug retention
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:uu:diva-90320 (URN)10.3109/08982109909044492 (DOI)000079495400006 ()
    Available from: 2003-04-30 Created: 2003-04-30 Last updated: 2017-12-14Bibliographically approved
    7. Development of EGF-conjugated liposomes for targeted delivery of boronated DNA-binding agents
    Open this publication in new window or tab >>Development of EGF-conjugated liposomes for targeted delivery of boronated DNA-binding agents
    Show others...
    2002 (English)In: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 13, no 4, p. 737-743Article in journal (Refereed) Published
    Abstract [en]

    Liposomes are of interest as drug delivery tools for therapy of cancer and infectious diseases. We investigated conjugation of epidermal growth factor, EGF, to liposomes using the micelle-transfer method. EGF was conjugated to the distal end of PEG−DSPE lipid molecules in a micellar solution and the EGF−PEG−DSPE lipids were then transferred to preformed liposomes, either empty or containing the DNA-binding compound, water soluble acridine, WSA. We found that the optimal transfer conditions were a 1-h incubation at 60 °C. The final conjugate, 125I-EGF−liposome−WSA, contained approximately 5 mol % PEG, 10−15 EGF molecules at the liposome surface, and 104 to 105 encapsulated WSA molecules could be loaded. The conjugate was shown to have EGF-receptor-specific cellular binding in cultured human glioma cells.

    National Category
    Organic Chemistry
    Identifiers
    urn:nbn:se:uu:diva-90321 (URN)10.1021/bc0100713 (DOI)
    Available from: 2003-04-30 Created: 2003-04-30 Last updated: 2018-12-04
  • 86.
    Bergstrand, Nill
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Bohl, Erika
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology, Biomedical Radiation Sciences.
    Carlsson, Jörgen
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology, Biomedical Radiation Sciences.
    Edwards, Katarina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Ghaneolhosseine, Hadi
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Gedda, Lars
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology, Biomedical Radiation Sciences.
    Jonsson, Markus
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Silvander, Mats
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Sjöberg, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Chemistry - BMC, Physical Organic Chemistry.
    Stabilised Liposomes with Double Targeting for Use in BNCT2000In: Contemporary Boron Chemistry / [ed] Matthew Davidson, Cambridge, UK: Royal Society of Chemistry, 2000, p. 131-134Chapter in book (Other academic)
  • 87.
    Bergstrand, Nill
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Edwards, Katarina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Aggregate structure in dilute aqueous dispersions of phospholipids, fatty acids and lysophospholipids2001In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 17, no 11, p. 3245-3253Article in journal (Refereed)
    Abstract [en]

    Cryo-transmission electron microscopy (cryo-TEM) was employed to investigate the aggregate structure in dilute aqueous dispersions of egg-phosphatidylcholine (EPC), oleic acid (OA), and the lysophospholipid monooleoylphosphatidylcholine (MOPC). At physiological pH and salt concentration, a relatively monodisperse population of unilamellar liposomes was detected in mixtures containing equimolar concentrations of the three components. Threadlike micelles constituted the dominant aggregate structure in samples containing high concentrations of MOPC. Excess fatty acid forced, on the other hand, the system toward structures with net negative curvature. In the absence of phospholipid, cryo-TEM revealed bilayer fragments in coexistence with threadlike micelles in mixtures containing the same molar amount of MOPC and OA. External addition of MOPC to preformed EPC liposomes gave rise to a concentration dependent evolution of intermediate structures, including open liposomes and bilayer fragments. The structural rearrangements were found to be slow and permitted visualization of a number of interesting transition structures. In addition to the structural studies, static and time-resolved fluorescence measurements were employed to determine some fundamental parameters for MOPC micelles. The results indicate a critical micelle concentration of close to 5 μM and an aggregation number of approximately 142.

  • 88.
    Bergstrand, Nill
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Edwards, Katarina
    Effects caused by PEO-PPO-PEO triblock copolymers on structure and stability of liposomal DOPE dispersions.Article in journal (Refereed)
  • 89.
    Bergstrand, Nill
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry. Department of Physical and Analytical Chemistry, Physical Chemistry I.
    Edwards, Katarina
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry. Department of Physical and Analytical Chemistry, Physical Chemistry I.
    Effects of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymers on structure and stability of liposomal dioleoylphosphatidylethanolamine2004In: Journal of Colloid and Interface Science, Vol. 276, no 2, p. 400-407Article in journal (Refereed)
  • 90. Beugin, S
    et al.
    Edwards, Katarina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Karlsson, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Ollivon, M
    Lesieur, S
    New sterically stabilized vesicles based on nonionic surfactant, cholesterol, and poly(ethylene glycol)-cholesterol conjugates.1998In: Biophysical Journal, ISSN 0006-3495, E-ISSN 1542-0086, Vol. 74, no 6, p. 3198-3210Article in journal (Other academic)
    Abstract [en]

    Monomethoxypoly(ethylene glycol) cholesteryl carbonates (M-PEG-Chol) with polymer chain molecular weights of 1000 (M-PEG1000-Chol) and 2000 (M-PEG2000-Chol) have been newly synthesized and characterized. Their aggregation behavior in mixture with diglycerol hexadecyl ether (C(16)G(2)) and cholesterol has been examined by cryotransmission electron microscopy, high-performance gel exclusion chromatography, and quasielastic light scattering. Nonaggregated, stable, unilamellar vesicles were obtained at low polymer levels with optimal shape and size homogeneity at cholesteryl conjugate/ lipids ratios of 10 mol% M-PEG1000-Chol or 5 mol% M-PEG2000-Chol, corresponding to the theoretically predicted brush conformational state of the PEG chains. At 20 mol% M-PEG1000-Chol or 10 mol% M-PEG2000-Chol, the saturation threshold of the C(16)G(2)/cholesterol membrane in polymer is exceeded, and open disk-shaped aggregates are seen in coexistence with closed vesicles. Higher levels up to 30 mol% lead to the complete solubilization of the vesicles into disk-like structures of decreasing size with increasing PEG content. This study underlines the bivalent role of M-PEG-Chol derivatives: while behaving as solubilizing surfactants, they provide an efficient steric barrier, preventing the vesicles from aggregation and fusion over a period of at least 2 weeks.

  • 91.
    Blom, A.
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry. Department of Physical and Analytical Chemistry, Physical Chemistry I.
    Duval, F. P.
    Kovacs, L.
    Warr, G. G.
    Almgren, M.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry. Department of Physical and Analytical Chemistry, Physical Chemistry I.
    Kadi, M.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry. Department of Physical and Analytical Chemistry, Physical Chemistry I.
    Zana, R.
    Direct visualization of mesh structures at solid/solution interfaces by atomic force microscopy2004In: Langmuir, Vol. 20, no 4, p. 1291-1297Article in journal (Other scientific)
  • 92. Blom, A.
    et al.
    Duval, F. P.
    Kovács, L.
    Warr, G. G.
    Almgren, M.
    Kadi, M.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry.
    Zana, R.
    Direct Visualization of Mesh Phases at Solid/Solution Interfaces by AFMArticle in journal (Refereed)
  • 93.
    Bohl, E.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Carlsson, J.
    Edwards, K.
    Sjöberg, S.
    Gedda, L.
    SLT-particles for two step targeting in boron neutron capture therapy2001In: Frontiers in Neutron Capture Therapy, Kluwer Academic/Plenum Publishers, New York , 2001Chapter in book (Other academic)
  • 94.
    Bohl Kullberg, Erika
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology, Biomedical Radiation Sciences.
    Bergstrand, Nill
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Carlsson, Jörgen
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology, Biomedical Radiation Sciences.
    Edwards, Katarina
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Johnsson, Markus
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Sjöberg, Stefan
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Biochemistry and Organic Chemistry, Organic Chemistry.
    Gedda, Lars
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Oncology, Radiology and Clinical Immunology, Biomedical Radiation Sciences.
    Development of EGF-conjugated liposomes for targeted delivery of boronated DNA-binding agents2002In: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 13, no 4, p. 737-743Article in journal (Refereed)
    Abstract [en]

    Liposomes are of interest as drug delivery tools for therapy of cancer and infectious diseases. We investigated conjugation of epidermal growth factor, EGF, to liposomes using the micelle-transfer method. EGF was conjugated to the distal end of PEG−DSPE lipid molecules in a micellar solution and the EGF−PEG−DSPE lipids were then transferred to preformed liposomes, either empty or containing the DNA-binding compound, water soluble acridine, WSA. We found that the optimal transfer conditions were a 1-h incubation at 60 °C. The final conjugate, 125I-EGF−liposome−WSA, contained approximately 5 mol % PEG, 10−15 EGF molecules at the liposome surface, and 104 to 105 encapsulated WSA molecules could be loaded. The conjugate was shown to have EGF-receptor-specific cellular binding in cultured human glioma cells.

  • 95.
    Boija, Elisabet
    et al.
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry.
    Lundquist, Anna
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry. Department of Physical Chemistry.
    Martínez Pla, Juan José
    Engvall, Caroline
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry.
    Lundahl, Per
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Biochemistry.
    Effects of ions and detergents in drug partition chromatography on liposomes2004In: Journal of chromatography A, Vol. 1030, p. 273-278Article in journal (Refereed)
    Abstract [en]

    We have determined drug partitioning into phospholipid bilayers by immobilized-liposome chromatography. Electrostatic effects on the drug partitioning were observed on neutral bilayers at low ionic strength. The size of the counterions affected the partitioning. When liposomes were supplemented with ionic detergents the partitioning of charged drugs was strongly affected, allowing complete separation of drugs of different charges which showed similar retention on neutral bilayers. Partial separation was obtained on bilayers containing fatty acid. Detergent ions or fatty acid inserted into phospholipid bilayers affected the partitioning of drugs much more than did free ions or phospholipid head group charges.

  • 96. Bonini, Massimo
    et al.
    Berti, Debora
    Di Meglio, Jean Marc
    Almgren, Mats
    Uppsala University, Teknisk-naturvetenskapliga vetenskapsområdet, Chemistry, Department of Physical Chemistry. Department of Physical and Analytical Chemistry, Physical Chemistry I.
    Teixeira, Jose
    Baglioni, Piero
    Surfactant aggregates hosting a photoresponsive amphiphile: Structure and photoinduced conformational changes2005In: Soft Matter, Vol. 1, no 6, p. 444-454Article in journal (Refereed)
  • 97.
    Boomer, Jeremy A.
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical Chemistry.
    Inerowicz, Halina D.
    Zhang, Zhi-Yi
    Bergstrand, Nill
    Edwards, Katarina
    Kim, Jong-Mok
    Thompson, David H.