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  • 51.
    Nilsson, Ulrika K.
    et al.
    Linköpings universitet, Institutionen för medicin och hälsa, Farmakologi. Linköpings universitet, Hälsouniversitetet.
    Andersson, Rolf G. G.
    Linköpings universitet, Institutionen för medicin och hälsa, Farmakologi. Linköpings universitet, Hälsouniversitetet.
    Ekeroth, Johan
    Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Hallin, Elisabeth C.
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Cellbiologi. Linköpings universitet, Hälsouniversitetet.
    Konradsson, Peter
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Organisk Kemi. Linköpings universitet, Tekniska högskolan.
    Lindberg, Jan
    Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Svensson, Samuel P.S.
    Linköpings universitet, Institutionen för medicin och hälsa, Farmakologi. Linköpings universitet, Hälsouniversitetet.
    Lack of stereospecificity in lysophosphatidic acid enantiomerinduced calcium mobilization in human erythroleukemia cells2003Inngår i: Lipids, ISSN 0024-4201, Vol. 38, nr 10, s. 1057-1064Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Lysophosphatidic acid (LPA) is a lipid mediator that, among several other cellular responses, can stimulate cells to mobilize calcium (Ca2+). LPA is known to activate at least three different subtypes of G protein-coupled receptors. These receptors can then stimulate different kinds of G proteins. In the present study, LPA and LPA analogs were synthesized from (R)- and (S)-glycidol and used to characterize the ability to stimulate Ca2+ mobilization. The cytosolic Ca2+ concentration ([Ca2+]i) was measured in fura-2-acetoxymethylester-loaded human erythroleukemia (HEL) cells. Furthermore, a reverse transcriptase polymerase chain reaction was used to characterize LPA receptor subtypes expressed in HEL cells. The results show that HEL cells mainly express LPA1 and LPA2, although LPA3 might possibly be expressed as well. Moreover, LPA and its analogs concentration-dependently increased [Ca2+]i in HEL cells. The response involved both influx of extracellular Ca2+ and release of Ca2+ from intracellular stores. This is the first time the unnatural (S)-enantiomer of LPA, (S)-3-O-oleoyl-1-O-phosphoryl-glycerol, has been synthesized and studied according to its ability to activate cells. The results indicate that this group of receptors does not discriminate between (R)- and (S)-enantiomers of LPA and its analogs. When comparing ether analogs having different hydrocarbon chain lengths, the tetradecyl analog (14 carbons) was found to be the most effective in increasing [Ca2+]i. Pertussis toxin treatment of the HEL cells resulted in an even more efficient Ca2+ mobilization stimulated by LPA and its analogs. Furthermore, at repeated incubation with the same ligand no further increase in [Ca2+]i was obtained. When combining LPA with the ether analogs no suppression of the new Ca2+ signal occurred. All these findings may be of significance in the process of searching for specific agonists and antagonists of the LPA receptor subtypes.

  • 52.
    Ottosson, Nina
    et al.
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelningen för cellbiologi. Linköpings universitet, Medicinska fakulteten.
    Wu, Xiongyu
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Nolting, Andreas
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelningen för cellbiologi. Linköpings universitet, Medicinska fakulteten.
    Karlsson, Urban
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelningen för cellbiologi. Linköpings universitet, Medicinska fakulteten.
    Lund, Per-Eric
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelningen för cellbiologi. Linköpings universitet, Medicinska fakulteten.
    Ruda, Katinka
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska fakulteten.
    Svensson, Stefan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Konradsson, Peter
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Elinder, Fredrik
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelningen för cellbiologi. Linköpings universitet, Medicinska fakulteten.
    Resin-acid derivatives as potent electrostatic openers of voltage-gated K channels and suppressors of neuronal excitability2015Inngår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 5, nr 13278Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Voltage-gated ion channels generate cellular excitability, cause diseases when mutated, and act as drug targets in hyperexcitability diseases, such as epilepsy, cardiac arrhythmia and pain. Unfortunately, many patients do not satisfactorily respond to the present-day drugs. We found that the naturally occurring resin acid dehydroabietic acid (DHAA) is a potent opener of a voltage-gated K channel and thereby a potential suppressor of cellular excitability. DHAA acts via a non-traditional mechanism, by electrostatically activating the voltage-sensor domain, rather than directly targeting the ion-conducting pore domain. By systematic iterative modifications of DHAA we synthesized 71 derivatives and found 32 compounds more potent than DHAA. The most potent compound, Compound 77, is 240 times more efficient than DHAA in opening a K channel. This and other potent compounds reduced excitability in dorsal root ganglion neurons, suggesting that resin-acid derivatives can become the first members of a new family of drugs with the potential for treatment of hyperexcitability diseases.

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  • 53.
    Persson, Kristin M
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Gabrielsson, Roger
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Sawatdee, Anurak
    Department of Printed Electronics, Acreo Swedish ICT AB, Norrköping, Sweden.
    Nilsson, David
    Department of Printed Electronics, Acreo Swedish ICT AB, Norrköping, Sweden.
    Konradsson, Peter
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Berggren, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Electronic control over detachment of a self-doped water-soluble conjugated polyelectrolyte2014Inngår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 30, nr 21, s. 6257-6266Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Water-soluble conducting polymers are of interest to enable more versatile processing in aqueous media as well as to facilitate interactions with biomolecules. Here, we report a substituted poly(3,4-ethylenedioxythiophene) derivative (PEDOT-S:H) that is fully water-soluble and selfdoped. When electrochemically oxidizing a PEDOT-S:H thin film, the film detaches from the under-laying electrode. The oxidation of PEDOT-S:H starts with an initial phase of swelling followed by cracking before it finally disrupts and detaches from the electrode. We investigated the detachment mechanism and found that parameters such as the size, charge and concentration of ions in the electrolyte, the temperature and also the pH influence the characteristics of detachment. When oxidizing PEDOT-S:H, the positively charged polymer backbone is balanced by anions from the electrolyte solution and also by the sulphonate groups on the side chains (more self-doping). From our experiments, we conclude that detachment of the PEDOT-S:H film upon oxidation occurs in part due to swelling caused by an inflow of solvated anions and associated water, and in part due to rearrangements and strain within the film, caused by more self-doping. We believe that PEDOT-S:H detachment can be of interest in a number of different applications, including addressed and active control of the release of materials such as biomolecules and cell cultures.

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  • 54.
    Persson, Kristin M
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Karlsson, Roger
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Organisk Kemi. Linköpings universitet, Tekniska högskolan.
    Svennersten, Karl
    Karolinska Institutet.
    Löffler, Susanne
    Karolinska Institutet.
    Jager, Edwin W H
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Richter-Dahlfors, Agneta
    Karolinska Institutet.
    Konradsson, Peter
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Organisk Kemi. Linköpings universitet, Tekniska högskolan.
    Berggren, Magnus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Electronic control of cell detachment using a self-doped conducting polymer2011Inngår i: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 23, nr 38, s. 4403-4408Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An electronic detachment technology based on thin films of a poly(3,4-ethylene-dioxythiophene) derivative is evaluated for controlled release of human epithelial cells. When applying a potential of 1 V, the redox-responsive polymer films detach and disintegrate and at the same time release cells cultured on top in the absence of any enzymatic treatment with excellent preservation of membrane proteins and cell viability.

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  • 55.
    Ruda, K.
    et al.
    Department of Organic Chemistry, Arrhenius Lab., Stockholm Univ., S., Stockholm, Sweden.
    Lindberg, Jan
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Garegg, P.J.
    Department of Organic Chemistry, Arrhenius Lab., Stockholm Univ., S., Stockholm, Sweden.
    Oscarson, S.
    Department of Organic Chemistry, Arrhenius Lab., Stockholm Univ., S., Stockholm, Sweden.
    Konradsson, Peter
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Organisk Kemi.
    Synthesis of an inositol phosphoglycan fragment found in Leishmania parasites2000Inngår i: Tetrahedron, ISSN 0040-4020, E-ISSN 1464-5416, Vol. 56, nr 24, s. 3969-3975Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Synthesis of 1 and 2a is described using a block synthetic strategy. Compound 4 was used as precursor for the two mannose derivatives which, coupled together, forms the dimannoside building block. Thioglycoside 7 was coupled to 8 yielding inositol phosphoglycan 9a, which was selectively deprotected and reacted with 2,3,4,6-tetra-O-benzyl-a-D-glucopyranos-1-yl H- phosphonate to form the protected target molecule 12. Deprotection of 12 by acidic deacetalisation/desilylation and subsequent catalytic hydrogenolysis resulted in cleavage of the anomeric phosphodiester to produce 1. Debenzylation with sodium in liquid ammonia followed by acidic deacetalisation/desilylation gave the target compound 2a. (C) 2000 Published by Elsevier Science Ltd.

  • 56.
    Silverå Ejneby, Malin
    et al.
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelning för neurobiologi. Linköpings universitet, Medicinska fakulteten.
    Wu, Xiongyu
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Ottosson, Nina
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelning för neurobiologi. Linköpings universitet, Medicinska fakulteten.
    Münger, E Peter
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Teoretisk Fysik. Linköpings universitet, Tekniska fakulteten.
    Lundström, Ingemar
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensor- och aktuatorsystem. Linköpings universitet, Tekniska fakulteten.
    Konradsson, Peter
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Elinder, Fredrik
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelning för neurobiologi. Linköpings universitet, Medicinska fakulteten.
    Atom-by-atom tuning of the electrostatic potassium-channel modulator dehydroabietic acid2018Inngår i: The Journal of General Physiology, ISSN 0022-1295, E-ISSN 1540-7748, Vol. 150, nr 5, s. 731-750Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Dehydroabietic acid (DHAA) is a naturally occurring component of pine resin that was recently shown to open voltage-gated potassium (KV) channels. The hydrophobic part of DHAA anchors the compound near the channel’s positively charged voltage sensor in a pocket between the channel and the lipid membrane. The negatively charged carboxyl group exerts an electrostatic effect on the channel’s voltage sensor, leading to the channel opening. In this study, we show that the channel-opening effect increases as the length of the carboxyl-group stalk is extended until a critical length of three atoms is reached. Longer stalks render the compounds noneffective. This critical distance is consistent with a simple electrostatic model in which the charge location depends on the stalk length. By combining an effective anchor with the optimal stalk length, we create a compound that opens the human KV7.2/7.3 (M type) potassium channel at a concentration of 1 µM. These results suggest that a stalk between the anchor and the effector group is a powerful way of increasing the potency of a channel-opening drug.

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  • 57.
    Svedhem, Sofia
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska högskolan.
    Hollander, Carl-Åke
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    Shi, Jing
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Konradsson, Peter
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Organisk Kemi.
    Liedberg, Bo
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Svensson, Stefan
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Organisk Kemi.
    Synthesis of a series of oligo(ethylene glycol)-terminated alkanethiol amides designed to address structure and stability of biosensing interfaces2001Inngår i: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 66, nr 13, s. 4494-4503Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A strategy for the synthesis of a series of closely related oligo(ethylene glycol)-terminated alkanethiol amides (principally HS(CH2)mCONH(CH2CH2O)nH; m = 2, 5, 11, 15, n = 1, 2, 4, 6, 8, 10, 12) and analogous esters has been developed. These compounds were made to study the structure and stability of self-assembled monolayers (SAMs) on gold in the prospect of designing new biosensing interfaces. For this purpose, monodisperse heterofunctional oligo(ethylene glycols) with up to 12 units were prepared. Selective monoacylation of the symmetrical tetra- and hexa(ethylene glycol) diols as their mesylates with the use of silver(I) oxide was performed. The synthetic approach was based on carbodiimide couplings of various oligo(ethylene glycol) derivatives to ω-(acetylthio) carboxylic acids via a terminal amino or hydroxyl function. SAM structures on gold were studied with respect to thickness, wettability (water contact angles ∼30°), and conformation. A good fit was obtained for the relation between monolayer thickness (d) and the number of units in the oligo(ethylene glycol) chain (n):  d = 2.8n + 21.8 (Å). Interestingly, the corresponding infrared spectroscopy analysis showed a dramatic change in conformation of the oligomeric chains from all-trans (n = 4) to helical (n ≥ 6) conformation. A crystalline helical structure was observed in the SAMs for n > 6.

  • 58.
    Svedhem, Sofia
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska högskolan.
    ÖPhberg, Liselotte
    Department of Organic Chemistry, Arrhenius Laboratory, Stockholms universitet, Sweden / AstraZeneca Södertälje, Södertälje, Sweden.
    Borrelli, Silvia
    Division of Clinical Bacteriology, Karolinska Institute, Huddinge University Hospital, SE-141 86 Huddinge, Sweden / Institute of Biological Sciences, National Research Council of Canada, Ottawa, Ont. KIA OR6, Canada.
    Valiokas, Ramunas
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Andersson, Mats
    Department of Organic Chemistry, Arrhenius Laboratory, Stockholms universitet, SE-106 91 Stockholm, Sweden, Medicarb, Annedalsvägen 37, SE-168 65 Bromma, Sweden.
    Oscarson, Stefan
    Department of Organic Chemistry, Arrhenius Laboratory, Stockholms universitet, SE-106 91 Stockholm, Sweden.
    Svensson, Stefan
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Organisk Kemi.
    Liedberg, Bo
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Konradsson, Peter
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Organisk Kemi.
    Synthesis and self-assembly of globotriose derivatives: A model system for studies of carbohydrate-protein interactions2002Inngår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 18, nr 7, s. 2848-2858Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Self-assembled monolayers (SAMs) on gold exposing a-D-Galp-(1 ? 4)-ß-D-Galp-(1?4)-ß-D-Glcp (globotriose) are described. A synthetic pathway for the preparation of the bioactive carbohydrate globotriose coupled directly to bis(16-hydroxyhexadecanyl) disulfide ((HOC16H32S)2), as well as via tetra- or di(ethylene glycol) spacers, was developed. The SAMs were characterized by ellipsometry, contact angle goniometry, infrared reflection-absorption spectroscopy, and by their interactions with monoclonal antibodies. The ellipsometry measurements of mixed SAMs revealed thicknesses between 22 and 40 Å, depending on the ratio between carbohydrate and non-carbohydrate disulfides in the preparation solution. When the solution contained 10% or more of the carbohydrate adsorbate, the modified gold substrates displayed total wetting. Infrared reflection-absorption spectroscopy conferred well-ordered SAMs with a high degree of crystallinity. Furthermore, two monoclonal antibodies (IgM, MAHI 419 and IgG, MAHI 5) showed different affinity for mixed SAMs depending on the fraction and the structure of the carbohydrate component used (globotriose or globotriose tetra(ethylene glycol)), with the largest amount of protein bound for MAHI 419 at 1-10% of surface carbohydrate. These results demonstrate the usefulness of the SAM approach to explore molecular details such as the effect of a spacer or antigen distribution on antibody interactions at interfaces.

  • 59.
    Tengdelius, Mattias
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Gurav, Deepanjali
    Uppsala University, Sweden; Savitri Bai Phule Pune University, India.
    Konradsson, Peter
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Påhlsson, Peter
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelningen för cellbiologi. Linköpings universitet, Medicinska fakulteten.
    Griffith, May
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelningen för cellbiologi. Linköpings universitet, Medicinska fakulteten.
    Oommen, Oommen P.
    Uppsala University, Sweden.
    Synthesis and anticancer properties of fucoidan-mimetic glycopolymer coated gold nanoparticles2015Inngår i: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 51, nr 40, s. 8532-8535Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Gold nanoparticles coated with fucoidan-mimetic glycopolymers were synthesized that displayed good colloidal stability and promising anti-cancer properties. Fucoidan mimetic glycopolymers on their own were nontoxic, while glycopolymer coated gold nanoparticles displayed selective cytotoxicity to human colon cancer cell lines (HCT116) while it was non-toxic to mouse fibroblast cells (NIH3T3).

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  • 60.
    Tengdelius, Mattias
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska högskolan.
    Lee, Chyan-Jang
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Grenegård, Magnus
    Linköpings universitet, Institutionen för medicin och hälsa, Avdelningen för läkemedelsforskning. Linköpings universitet, Hälsouniversitetet.
    Griffith, May
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelningen för cellbiologi. Linköpings universitet, Hälsouniversitetet.
    Påhlsson, Peter
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelningen för cellbiologi. Linköpings universitet, Hälsouniversitetet.
    Konradsson, Peter
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska högskolan.
    Synthesis and biological evaluation of fucoidan-mimetic glycopolymers through cyanoxyl-mediated free-radical polymerization2014Inngår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 15, nr 7, s. 2359-2368Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The sulfated marine polysaccharide fucoidan has been reported to have health benefits ranging from antivirus and anticancer properties to modulation of high blood pressure. Hence, they could enhance the biological function of materials for biomedical applications. However, the incorporation of fucoidan into biomaterials has been difficult, possibly due to its complex structure and lack of suitable functional groups for covalent anchoring to biomaterials. We have developed an approach for a rapid synthesis of fucoidanmimetic glycopolymer chains through cyanoxyl-mediated free-radical polymerization, a method suitable for chain-end functionalizing and subsequent linkage to biomaterials. The resulting sulfated and nonsulfated methacrylamido alpha-L-fucoside glycopolymers fucoidan-mimetic properties were studied in HSV-1 infection and platelet activation assays. The sulfated glycopolymer showed similar properties to natural fucoidan in inducing platelet activation and inhibiting HSV-1 binding and entry to cells, thus indicating successful syntheses of fucoidan-mimetic glycopolymers.

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  • 61.
    Uvdal, Kajsa
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Ekeroth, Johan
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Konradsson, Peter
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Organisk Kemi.
    Liedberg, Bo
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Tyrosine derivatives assembled on gold2003Inngår i: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 260, nr 2, s. 361-366Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 62.
    Uvdal, Kajsa
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Petoral, Rodrigo Jr
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Söderlind, Fredrik
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Käll, Per-Olov
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Fysikalisk Kemi.
    Konradsson, Peter
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Organisk Kemi.
    Engström, Maria
    Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för klinisk och experimentell medicin, Cellbiologi. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Magnetic circular X-ray dichroism of Gd2O3 nano particles2003Inngår i: AVS,2003, 2003Konferansepaper (Annet vitenskapelig)
  • 63.
    Valiokas, Ramunas
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    Östblom, Mattias
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Björefors, Fredrik
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Liedberg, Bo
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Shi, Jing
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    Konradsson, Peter
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Organisk Kemi.
    Structural and kinetic properties of laterally stabilized, oligo(ethylene glycol)-containing alkylthiolates on gold: A modular approach2006Inngår i: Biointerphases, ISSN 1934-8630, E-ISSN 1559-4106, Vol. 1, nr 1, s. 22-34Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The formation of highly ordered self-assembled monolayers (SAMs) on goldfrom an unusually long and linear compound HS(CH2)15CONH(CH2CH2O)6CH2CONH(CH2)15CH3 is investigated by contact angle goniometry, ex situ null ellipsometry, cyclic voltammetry and infrared reflection-absorption spectroscopy. The molecules are found to assemble in an upright position as a complete monolayer within 60 min. The overall structure of the SAM reaches equilibrium within 24 h as evidenced by infrared spectroscopy, although a slight improvement in water contact angles is observed over a period of a few weeks. The resulting SAM is 60 Å thick and it displays an advancing water contact angle of 112° and excellent electrochemicalblocking characteristics with typical current densities about 20 times lower as compared to those observed for HS(CH2)15CH3 SAMs. The dominating crystalline phases of the supporting HS(CH2)15 and terminal (CH2)15CH3 alkyl portions, as well as the sealed oligo(ethylene glycol) (OEG) “core,” appear as unusually sharp features in the infrared spectra at room temperature. For example, the splitting seen for the CH3 stretching and CH2 scissoring peaks is normally only observed for conformationally trapped alkylthiolate SAMs at low temperatures and for highly crystalline polymethylenes. Temperature-programmed infrared spectroscopy in ultrahigh vacuum reveals a significantly improved thermal stability of the SAM under investigation, as compared to two analogous OEG derivatives without the extended alkyl chain. Our study points out the advantages of adopting a “modular approach” in designing novel SAM-forming compounds with precisely positioned in plane stabilizing groups. We demonstrate also the potential of using the above set of compounds in the fabrication of “hydrogel-like” arrays with controlled wetting properties for application in the ever-growing fields of protein and cell analysis, as well as for bioanalytical applications.

  • 64.
    Vikström, Elena
    et al.
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Medicinsk mikrobiologi. Linköpings universitet, Hälsouniversitetet.
    Bui, Lan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Konradsson, Peter
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Organisk Kemi. Linköpings universitet, Tekniska högskolan.
    Magnusson, Karl-Eric
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Medicinsk mikrobiologi. Linköpings universitet, Hälsouniversitetet.
    Role of calcium signalling and phosphorylations in disruption of the epithelial junctions by Pseudomonas aeruginosa quorum sensing molecule2010Inngår i: European Journal of Cell Biology, ISSN 0171-9335, E-ISSN 1618-1298, Vol. 89, nr 8, s. 584-597Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In Pseudomonas aeruginosa. cell-cell communication based on acyl-homoserine lactone (HSL) quorum sensing molecules is known to coordinate the production of virulence factors and biofilms by the bacterium. Incidentally, these bacterial signals can also modulate mammalian cell behaviour. We demonstrate here that 3O-C-12-HSL can induce changes in calcium signalling through influx and release of calcium from thapsigargin-sensitive stores and delocalization of inositol 1,4,5-trisphosphate receptors (IP3R), but not of ryanodine receptors (RyR). In parallel, P. aeruginosa 3O-C-12-HSL disrupts junctions in human Caco-2 cells as evidenced by a reduction of the expression and distribution of ZO-3 and JAM-A. Using co-immunoprecipitation we also found an alteration in the binding of ZO-3 to JAM-A in protein complexes. Moreover, 3O-C-12-HSL-treatment resulted in tyrosine hyperphosphorylation of ZO-3 and JAM-A. On the contrary, serine and threonine residues of ZO-1 and JAM-A became less phosphorylated after exposition of 3O-C-12-HSL. The 3O-C-12-HSL-induced intracellular calcium signalling and alteration in the phosphorylation status of junction proteins furthermore correlated with changes in the association between JAM-A-ZO-3. The calcium inhibitors thapsigargin, xestospongin C. and dantrolene partly prevented the 3O-C-12-HSL-induced decreases in TER and increases in the paracellular flux of 10 kDa dextran. These findings clearly suggest that P. aeruginosa 3O-C-12-HSL can cause the loss of epithelial barrier function via calcium signalling and further alteration in the phosphorylation status of junction proteins; and that bacterial quorum sensing signals represent inter-kingdom signalling.

  • 65.
    Vikström, Elena
    et al.
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Medicinsk mikrobiologi. Linköpings universitet, Hälsouniversitetet.
    Bui, Lan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Konradsson, Peter
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Magnusson, Karl-Eric
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Medicinsk mikrobiologi. Linköpings universitet, Hälsouniversitetet.
    The junctional integrity of epithelial cells is modulated by Pseudomonas aeruginosa quorum sensing molecule through phosphorylation-dependent mechanisms2009Inngår i: Experimental Cell Research, ISSN 0014-4827, E-ISSN 1090-2422, Vol. 315, nr 2, s. 313-326Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In Pseudomonas aeruginosa, cell-cell Communication based on acyl-homoserine lactone (HSL) quorum sensing molecules is known to coordinate the production of virulence factors and biofilms by the bacterium. Incidentally, these bacterial signals can also modulate mammalian cell behaviour. We report that 3O-C-12-HSL can disrupt adherens junctions in human epithelial Caco-2 cells as evidenced by a reduction of the expression and distribution of E-cadherin and beta-catenin. Using co-immunoprecipitation we also found that P. aeruginosa 3O-C-12-HSL-treatment resulted in tyrosine hyperphosphorylation of E-cadherin, beta-catenin, occludin and ZO-1. Similarly, serine and threonine residues of E-cadherin and ZO-1 became more phosphorylated after 3O-C-12-HSL treatment. On the contrary, occludin and beta-catenin underwent dephosphorylation on serine and threonine residues after exposition of 3O-C-12-HSL. These changes in the phosphorylation state were paralleled by alteration in the Structure of junction complexes and increased paracellular permeability. Moreover, pre-treatment of the Caco-2 cells with protein phosphatase and kinase inhibitors prevented 3O-C-12-HSL-induced changes in paracellular permeability and interactions between occludin-ZO-1 and the E-cadherin-beta-catenin. These findings clearly suggest that an alteration in the phosphorylation status of junction proteins are involved in the changes in cell junction associations and enhanced paracellular permeability, and that bacterial signals are indeed sensed by the host cells.

  • 66.
    Zhang, Jun
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär ytfysik och nanovetenskap. Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi.
    Sandberg, Alexander
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Wu, Xiongyu
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Nyström, Sofie
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Lindgren, Mikael
    Department of Physics, The Norwegian University of Science and Technology, Trondheim, Norway.
    Konradsson, Peter
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Hammarström, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    trans-Stilbenoids with Extended Fluorescence Lifetimes for the Characterization of Amyloid Fibrils2017Inngår i: ACS Omega, ISSN 2470-1343, Vol. 2, nr 8, s. 4693-4704Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    It was previously reported that two naphthyl-based trans-stilbene probes, (E)-4-(2-(naphthalen-1-yl)vinyl)benzene-1,2-diol (1) and (E)-4-(2-(naphthalen-2-yl)vinyl)benzene-1,2-diol (3), can bind to both native transthyretin (TTR) and misfolded protofibrillar TTR at physiological concentrations, displaying distinct emission maxima bound to the different conformational states (>100 nm difference). To further explore this amyloid probe scaffold to obtain extended fluorescence lifetimes, two new analogues with expanded aromatic ring systems (anthracene and pyrene), (E)-4-(2-(anthracen-2-yl)vinyl)benzene-1,2-diol (4) and (E)-4-(2-(pyren-2-yl)vinyl)benzene-1,2-diol (5), were synthesized employing the palladium-catalyzed Mizoroki–Heck reaction. (E)-4-Styrylbenzene-1,2-diol (2), 3, 4, and 5 were investigated with respect to their photophysical properties in methanol and when bound to insulin, lysozyme, and Aβ1-42 fibrils, including time-resolved fluorescence measurements. In conclusion, 4 and 5 can bind to both native and fibrillar TTR, becoming highly fluorescent. Compounds 2–5 bind specifically to insulin, lysozyme, and Aβ1-42 fibrils with an apparent fluorescence intensity increase and moderate binding affinities. The average fluorescence lifetimes of the probes bound to Aβ1-42 fibrils are 1.3 ns (2), 1.5 ns (3), 5.7 ns (4), and 29.8 ns (5). In summary, the variable aromatic moieties of the para-positioned trans-stilbenoid vinyl-benzene-1,2-diol with benzene, naphthalene, anthracene, and pyrene showed that the extended conjugated systems retained the amyloid targeting properties of the probes. Furthermore, both the anthracene and pyrene moieties extensively enhanced the fluorescence intensity and prolonged lifetimes. These attractive probe properties should improve amyloid detection and characterization by fluorescence-based techniques.

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    fulltext
  • 67.
    Zhang, Jun
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Wang, Jun
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Bioinformatik. Linköpings universitet, Tekniska fakulteten.
    Sandberg, Alexander
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Wu, Xiongyu
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Nyström, Sofie
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    LeVine, Harry III
    Sanders-Brown Center on Aging, University of Kentucky, KY 40536-0230, Lexington, USA..
    Konradsson, Peter
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Hammarström, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Durbeej, Bo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Bioinformatik. Linköpings universitet, Tekniska fakulteten.
    Lindgren, Mikael
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten. Department of Physics, Norwegian University of Science and Technology, 7491, Trondheim, Norway..
    Intramolecular Proton and Charge Transfer of Pyrene-based trans-Stilbene Salicylic Acids Applied to Detection of Aggregated Proteins.2018Inngår i: ChemPhysChem, ISSN 1439-4235, E-ISSN 1439-7641, Vol. 19, nr 22, s. 3001-3009Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Two analogues to the fluorescent amyloid probe 2,5-bis(4'-hydroxy-3'-carboxy-styryl)benzene (X-34) were synthesized based on the trans-stilbene pyrene scaffold (Py1SA and Py2SA). The compounds show strikingly different emission spectra when bound to preformed Aβ1-42 fibrils. This remarkable emission difference is retained when bound to amyloid fibrils of four distinct proteins, suggesting a common binding configuration for each molecule. Density functional theory calculations show that Py1SA is twisted, while Py2SA is more planar. Still, an analysis of the highest occupied molecular orbitals (HOMOs) and lowest unoccupied molecular orbitals (LUMOs) of the two compounds indicates that the degree of electronic coupling between the pyrene and salicylic acid (SA) moieties is larger in Py1SA than in Py2SA. Excited state intramolecular proton transfer (ESIPT) coupled-charge transfer (ICT) was observed for the anionic form in polar solvents. We conclude that ICT properties of trans-stilbene derivatives can be utilized for amyloid probe design with large changes in emission spectra and decay times from analogous chemical structures depending on the detailed physical nature of the binding site.less thanbr /greater than (© 2018 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim.)

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  • 68.
    Åslund, Andreas
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Organisk Kemi. Linköpings universitet, Tekniska högskolan.
    Herland, Anna
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Hammarström, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biokemi. Linköpings universitet, Tekniska högskolan.
    Nilsson, Peter
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Organisk Kemi. Linköpings universitet, Tekniska högskolan.
    Jonsson, Bengt-Harald
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär Bioteknik. Linköpings universitet, Tekniska högskolan.
    Inganäs, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Konradsson, Peter
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Organisk Kemi. Linköpings universitet, Tekniska högskolan.
    Studies of luminescent conjugated polythiophene derivatives-Enhanced spectral discrimination of protein conformational states2007Inngår i: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 18, nr 6, s. 1860-1868Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Improved probes for amyloid fibril formation are advantageous for the early detection and better understanding of this disease-associated process. Here, we report a comparative study of eight luminescent conjugated polythiophene derivates (LCPs) and their discrimination of a protein (insulin) in the native or amyloid-like fibrillar state. For two of the LCPs, the synthesis is reported. Compared to their monomer-based analogues, trimer-based LCPs showed significantly better optical signal specificity for amyloid-like fibrils, seen from increased quantum yield and spectral shift. The trimer-based LCPs alone were highly quenched and showed little interaction with native insulin, as seen from analytical ultracentrifugation and insignificant spectral differences from the trimer-based LCP in buffered and native protein solution. Hence, the trimer-based LCPs showed enhanced discrimination between the amyloid-like fibrillar state and the corresponding native protein.

  • 69.
    Åslund, Andreas
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Organisk Kemi. Linköpings universitet, Tekniska högskolan.
    Nilsson, Peter
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Organisk Kemi. Linköpings universitet, Tekniska högskolan.
    Konradsson, Peter
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Organisk Kemi. Linköpings universitet, Tekniska högskolan.
    Synthesis of a pentathiophene fluorescent probe, 4’,3’’’-Bis-carboxymethyl-[2,2’;5’,2’’;5’’,2’’’;5’’’,2’’’‘]quinquethiophene-5,5’2010Inngår i: Nature Protocols, ISSN 1754-2189Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    Poly and oligo-thiophenes have previously been used for in vitro, ex vivo and in vivo imaging of protein aggregates. The probe (p-FTAA) has been developed for the purpose of in vivo staining of protein aggregates such as amyloid deposits. It effectively passes the blood brain barrier and imaging can be performed live with two-photon imaging or ex vivo.

    The straightforward synthesis of p-FTAA, including two Suzuki couplings, makes it an attractive probe for studies of most diseases involving protein aggregates.

  • 70.
    Åslund, Andreas
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Organisk Kemi. Linköpings universitet, Tekniska högskolan.
    Sigurdson, Christina J
    Institute of Neuropathology, Department of Pathology, Universitätsspital Zürich, Schmelzbergstrasse 12, CH-8091 Zürich, Switzerland.
    Klingstedt, Therése
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska fakulteten.
    Grathwohl, Stefan
    Department of Cellular Neurology, Hertie-Institute for Clinical Brain Research, University of Tuebingen, D-72076 Tuebingen, Germany.
    Bolmont, Tristan
    Department of Cellular Neurology, Hertie-Institute for Clinical Brain Research, University of Tuebingen, D-72076 Tuebingen, Germany.
    Dickstein, Dara L
    Department of Neuroscience, Mount Sinai School of Medicine, New York, New York 10029, USA.
    Glimsdal, Eirik
    Department of Physics, Norwegian University of Science and Technology, N-7491 Trondheim, Norway.
    Prokop, Stefan
    Department of Neuropathology, Charité-Universitätsmedizin Berlin, D-13353 Berlin, Germany.
    Lindgren, Mikael
    Department of Physics, Norwegian University of Science and Technology, N-7491 Trondheim, Norway.
    Konradsson, Peter
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Organisk Kemi. Linköpings universitet, Tekniska högskolan.
    Holtzman, David M
    Department of Neurology, Alzheimer’s Disease Research Center, Washington University, St. Louis, Missouri 63110, USA.
    Hof, Patrick R
    Department of Neuroscience, Mount Sinai School of Medicine, New York, New York 10029, USA.
    Heppner, Frank L
    Department of Neuropathology, Charité-Universitätsmedizin Berlin, D-13353 Berlin, Germany.
    Gandy, Samuel
    Alzheimer’s Disease Research Center, Mount Sinai School of Medicine, New York, New York 10029, USA.
    Jucker, Mathias
    Department of Cellular Neurology, Hertie-Institute for Clinical Brain Research, University of Tuebingen, D-72076 Tuebingen, Germany.
    Aguzzi, Adriano
    Institute of Neuropathology, Department of Pathology, Universitätsspital Zürich, Schmelzbergstrasse 12, CH-8091 Zürich, Switzerland.
    Hammarström, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biokemi. Linköpings universitet, Tekniska högskolan.
    Nilsson, Peter
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Organisk Kemi. Linköpings universitet, Tekniska högskolan.
    Novel Pentameric Thiophene Derivatives for in Vitro and in Vivo Optical Imaging of a Plethora of Protein Aggregates in Cerebral Amyloidoses2009Inngår i: ACS CHEMICAL BIOLOGY, ISSN 1554-8929, Vol. 4, nr 8, s. 673-684Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Molecular probes for selective Identification of protein aggregates are important to advance our understanding of the molecular pathogenesis underlying cerebral amyloidoses. Here we report the chemical design of pentameric thiophene derivatives, denoted luminescent conjugated oligothiophenes (LCOs), which could be used for real-time visualization of cerebral protein aggregates in transgenic mouse models of neurodegenerative diseases by multiphoton microscopy. One of the LCOs, p-FTAA, could be utilized for ex vivo spectral assignment of distinct prion deposits from two, mouse-adapted prion strains. p-FTAA also revealed a transient soluble pre-fibrillar non-thioflavinophilic A beta-assemblies during in vitro fibrillation of A beta peptides. In brain tissue samples, A beta deposits and neurofibrillary tangles (NFTs) were readily identified by a strong fluorescence from p-FTAA and the LCO staining showed complete co-localliation with conventional antibodies (6E10 and AT8). In addition, a patchy islet-like staining of individual A beta plaque was unveiled by the anti-oligomer A11 antibody during co-staining with p-FTAA. The major hallmarks of Alzheimers disease, namely, A beta aggregates versus NFTs, could also be distinguished because of distinct emission spectra from p-FTAA. Overall, we demonstrate that LCOs can be utilized as powerful practical research tools for studying protein aggregation diseases and facilitate the study of amyloid origin, evolution and maturation, A beta-tau interactions, and pathogenesis both ex vivo and in vivo.

  • 71.
    Östblom, Mattias
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Ekeroth, Johan
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Konradsson, Peter
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Organisk Kemi.
    Liedberg, Bo
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Structure and desorption energetics of ultrathin D2O ice overlay ers on serine- And serinephosphate-terminated self-assembled monolayers2006Inngår i: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 110, nr 4, s. 1695-1700Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper reports on the structure and desorption dynamics of thin D 2O ice overlayers (0.2-10 monolayers) deposited on serine- and serinephosphate- (with H+, Na+, Ca2+ counterions) terminated self-assembled monolayers (SAMs). The D2O ice overlayers are deposited on the SAMs at ~85 K in ultrahigh vacuum and characterized with infrared reflection absorption spectroscopy (IRAS). Reflection absorption (RA) spectra obtained at sub-monolayer D2O coverage reveal that surface modes, e.g. free dangling OD stretch, dominate on the serine SAM surface, whereas vibrational modes characteristic for bulk ice are more prominent on the serinephosphate SAMs. Temperature programmed desorption mass spectrometry (TPD-MS) and TPD-IRAS are subsequently used to investigate the energetics and the structural transitions occurring in the ice overlayer during temperature ramping. D2O ice (~2.5 monolayers) on the serine SAMs undergoes a gradual change from an amorphous- to a crystalline-like phase upon increasing the substrate temperature. This transition is not as pronounced on the serine phosphate SAM most likely because of reduced mobility due to strong pinning to the surface. We show also that the energy of desorption for a sub-monolayer of D2O ice on serinephosphate SAM surfaces with a Na+ and Ca2+ counterions is equally high or even exceeds previously reported values for analogous high-energy SAMs. © 2006 American Chemical Society.

  • 72.
    Östblom, Mattias
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Valiokas, Ramunas
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Konradsson, Peter
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Organisk Kemi.
    Svensson, Stefan
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Organisk Kemi.
    Liedberg, Bo
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Garrett, M.
    Department of Chemistry and Materials Science, Pennsylvania State University, University Park, PA 16802.
    Allara, D.L.
    Department of Chemistry and Materials Science, Pennsylvania State University, University Park, PA 16802.
    Ice nucleation and phase behavior on oligo(ethylene glycol) and hydroxyl self-assembled monolayers: Simulations and experiments2006Inngår i: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 110, nr 4, s. 1830-1836Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The nucleation and phase behavior of ultrathin D2O-ice overlayers have been studied on oligo(ethylene glycol) (OEG)-terminated and hydroxyl self-assembled monolayers (SAMs) at low temperatures in ultrahigh vacuum. Infrared reflection-absorption spectroscopy (IRAS) is used to characterize the ice overlayers, the SAMs, and the interactions occurring between the ice and the SAM surfaces. Spectral simulations, based on optical models in conjunction with Maxwell Garnett effective medium theory, point out the importance of including voids in the modeling of the ice structures, with void fractions reaching 60% in some overlayers. The kinetics of the phase transition from amorphous-like to crystalline-like ice upon isothermal annealing at 140 K is found to depend on the conformational state of the supporting OEG SAM surface. The rate is fast on the helical OEG SAMs and slow on the corresponding all-trans SAMs. This difference in kinetics is most likely due to a pronounced D2O interpenetration and binding to the all-trans segments of the ethylene glycol portion of the SAM. No such penetration and binding was observed on the helical OEG SAM. © 2006 American Chemical Society.

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