liu.seSök publikationer i DiVA
Ändra sökning
Avgränsa sökresultatet
12345 151 - 200 av 250
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Träffar per sida
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
Markera
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 151.
    Malysheva, Lyuba
    et al.
    Bogolyubov Inst fo Theoretical Physics, 03143 Kiev. Ukraine.
    Onipko, Alexander
    Div och Molecular Physics Department of Physics, Chemistry and Biology, Linköping University, 581 83 Linköping Sweden.
    Liedberg, Bo
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Orientation of OH terminal groups in oligo(ethylene glycol)-terminated self-assemblies: results of ab initio modeling2006Ingår i: Physica status solidi. B, Basic research, ISSN 0370-1972, E-ISSN 1521-3951, Vol. 243, nr 13, s. 3489-3493Artikel i tidskrift (Refereegranskat)
    Abstract [en]

       

  • 152.
    Marciniak Braun, Slawomir
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska högskolan.
    Crispin, Xavier
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    Uvdal, Kajsa
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Trzcinski, M.
    Institute of Mathematics and Physics, Bydgoszcz, Poland.
    Birgerson, J.
    LCD Technology, Dalarna University, Borlänge, Sweden.
    Groenendaal, L.
    Agfa-Gevaert N. V., R&D Materials/Chemistry Department, Mortsel, Belgium.
    Louwet, F.
    Agfa-Gevaert N. V., R&D Materials/Chemistry Department, Mortsel, Belgium.
    Salaneck, William R.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska högskolan.
    Light Induced Damage in Poly(3,4-ethylenedioxythiophene) and its Derivatives Studied by Photoelectron Spectroscopy2004Ingår i: Synthetic metals, ISSN 0379-6779, E-ISSN 1879-3290, Vol. 141, nr 1-2, s. 67-73Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 153.
    Masunaga, Kumi
    et al.
    Kyushu University Graduate School of Systems Life Sciences.
    Michiwaki, Shintaro
    Kyushu University Graduate School of Information Science and Electrial Engineering.
    Izumi, Ryosuke
    Kyushu University Graduate School of Information Science and Electrial Engineering.
    Ivarsson, Patrik
    Asko Cylinda AB .
    Björefors, Fredrik
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Lundström, Ingemar
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik.
    Hayashi, Kenshi
    Kyushu University Graduate School of Information Science and Electrial Engineering.
    Toko, Kiyoshi
    Kyushu University Graduate School of Information Science and Electrial Engineering.
    Development of sensor surface with recognition of molecular substructure2008Ingår i: Sensors and actuators. B, Chemical, ISSN 0925-4005, E-ISSN 1873-3077, Vol. 130, nr 1, s. 330-337Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A biological olfaction system is one of the highest performance chemical sensing systems for low-molecular-weight compounds. An ability of recognizing a various molecular properties based on their structures is essential for a biological odor recognition process. For the development of a sensor mimicking the olfactory system, we have formed benzene-patterned self-assembled monolayer (SAM) on the sensor surface using SAMs with nanostructure that serves as adsorption sites for benzene ring, which is representative substructure of aromatics. The structure of the benzene-patterned SAM surface was analyzed by contact-angle measurement, ellipsometry, cyclic voltammetry (CV) and atomic force microscopy (AFM). Moreover, the electrodes evaluated as sensor surfaces with cyclic surface-polarization impedance (cSPI) sensor that measures changes in impedance of the electrode surface by adsorption of substances. The results of cSPI indicated the benzene-patterned SAM surface could distinguish benzene by recognizing of the hydrophobicity and the molecular size. © 2007 Elsevier B.V. All rights reserved.

  • 154.
    Mehdi Shahjamali, Mohammad
    et al.
    Nanyang Technology University.
    Bosman, Michel
    ASTAR.
    Cao, Shaowen
    Nanyang Technology University.
    Huang, Xiao
    Nanyang Technology University.
    Saadat, Somaye
    Nanyang Technology University.
    Martinsson, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Aili, Daniel
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Yan Tay, Yee
    Nanyang Technology University.
    Liedberg, Bo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Chye Joachim Loo, Say
    Nanyang Technology University.
    Zhang, Hua
    Nanyang Technology University.
    Boey, Freddy
    Nanyang Technology University.
    Xue, Can
    Nanyang Technology University.
    Gold Coating of Silver Nanoprisms2012Ingår i: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 22, nr 4, s. 849-854Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Coreshell Ag@Au nanoprisms are prepared through a surfactant-free seed-mediated approach by taking advantage of the anisotropic structure of silver nanoprisms as seeds. The gold coating on the silver nanoprism surface is achieved by using hydroxylamine as a mild reducing agent, and the final fully gold-coated prism structures are confirmed by microscopic and spectroscopic characterization. The resulting Ag@Au coreshell structure preserves the optical signatures of nanoprisms and offers versatile functionality and particularly better stability against oxidation than the bare silver nanoprism. The surface plasmon resonances of the coreshell Ag@Au nanoprisms can be tuned throughout the visible and near-IR range as a function of the Au shell thickness. Such tailorable optical features and surfactant-free gold shells have great potential applications in biosensing and bioimaging.

  • 155.
    Music, Denis
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik.
    Schneider, Jochen
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Kugler, Veronika Mozhdeh
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Nakao, S.
    National Industrial Research Institute of Nagoya, Nagoya 462-8510, Japan.
    Jin, P.
    National Industrial Research Institute of Nagoya, Nagoya 462-8510, Japan.
    Östblom, Mattias
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Hultman, Lars
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik.
    Helmersson, Ulf
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Plasma och beläggningsfysik.
    Synthesis and mechanical properties of boron suboxide thin films2002Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 20, nr 2, s. 335-337Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The synthesis and mechanical properties of boron suboxide thin films deposited on silicon and graphite substrates was discussed. The deposition was performed using reactive magnetron sputtering technique, and amorphous films were obtained. The affect of varying O2 partial pressure on film composition and microstructure was studied using spectroscopic techniques. It was found that variation of partial pressure from 0.02 to 0.21 resulted in a decrease in elastic modulus from 272 to 109 GPa.

  • 156. Beställ onlineKöp publikationen >>
    Myrskog, Annica
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Self Assembled Monolayers for Quartz Crystal Microbalance based Biosensing2009Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The work in this thesis has been focused on developing surfaces for use in biosensor systems, especially for quartz crystal microbalances. The surfaces were prepared by adsorption of organosulfur molecules onto gold substrates, so called self assembled monolayers (SAMs). By chemical synthesis these thiols can be specifically tailored to provide surfaces with desired properties. The investigated surfaces were all based on thiols terminated with carboxylic acid groups to render hydrophilic surfaces onto which desired proteins can be covalently attached.

    In order to increase the performance of two dimensional carboxyl surfaces, a method for improving the immobilization of proteins to the surface was investigated. The immobilization levels of antibodies were increased by using N-hydroxysulfo-succinimide (sulfo-NHS), instead of N-hydroxy-succinimide (NHS), as stabilizer of the amine reactive intermediate formed by reaction of the carboxyl groups with 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride (EDC). The negatively charged sulfo-NHS intermediate promotes the attraction of overall positively charged proteins and enables immobilization also at low pH. In addition, the orientation of the immobilized antibodies was shown to be dependent on the pI of the antibody and to have a profound effect on the subsequent interaction with the antigen.

    The organization of carboxyl terminated SAMs can be poor due to the repellation between the polar terminal groups. By using acidified ethanol as solvent during the assembly step of monolayer formation, the organization in carboxyl terminated alkyl and oligo(ethylene glycol) SAMs was improved. However, the carboxyl groups were found to be converted to ethyl esters, the rate being related to the acid strength. Furthermore, the long-term stability of carboxyl oligo(ethylene glycol) SAMs was investigated. Here, the effect of alkyl chain length on the storage stability was of interest. A short alkyl chain was shown to have a profound negative effect on the storage stability of the SAM, resulting in decomposition and loss of functionality over time compared to when thiols with longer alkyl chains were studied.

    Delarbeten
    1. Optimizing immobilization conditions on a two dimensional carboxylbiosensor surface: pH dependence of antibody orientation andantigen binding capacity
    Öppna denna publikation i ny flik eller fönster >>Optimizing immobilization conditions on a two dimensional carboxylbiosensor surface: pH dependence of antibody orientation andantigen binding capacity
    2009 (Engelska)Ingår i: Analytical Biochemistry, ISSN 0003-2697, E-ISSN 1096-0309Artikel i tidskrift (Övrigt vetenskapligt) Submitted
    Abstract [en]

    The performance of immunosensors is highly dependent on the amount of immobilized antibodies and their remaining antigen binding capacity. In this work, a method for immobilization of antibodies on a two dimensional carboxyl surface has been optimized using quartz crystal microbalance biosensors. We have shown that successful immobilization is highly dependent on surface pKa, antibody pI and pH of immobilization buffer. By use of EDC/sulfo-NHS activation reagents, the effect of the intrinsic surface pKa is avoided and immobilization also at very low pH has been made possible which is of importance for immobilization of acidic proteins. Generic immobilization conditions were demonstrated on a panel of antibodies which resulted in an average coefficient of variation of 4% for the immobilization of these antibodies.

    Antigen binding capacity as a function of immobilization pH was studied. In most cases the antigen binding capacity followed the immobilization response. However, the antigen to antibody binding ratio differed between the antibodies investigated, and for one of the antibodies, the antigen binding capacity was significantly lower than expected from immobilization in a certain pH range. Tests with anti-Fc and anti-Fab antibodies on different antibody surfaces showed that the orientation of the antibodies on the surface had a profound effect on the antigen binding capacity of the immobilized antibodies.

    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-19690 (URN)
    Tillgänglig från: 2009-07-14 Skapad: 2009-07-14 Senast uppdaterad: 2017-12-13Bibliografiskt granskad
    2. Esterification of self-assembled carboxylic acid-terminated thiolmonolayers in acid environment: A time dependent study
    Öppna denna publikation i ny flik eller fönster >>Esterification of self-assembled carboxylic acid-terminated thiolmonolayers in acid environment: A time dependent study
    2010 (Engelska)Ingår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 26, nr 2, s. 821-829Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    This contribution reports on the influence of acids on the quality of carboxylic acid terminated self-assembled monolayers (SAMs) on gold prepared from ethanolic solution of HS-(CH2)15-COOH and HS-(CH2)11CONH–(EG)6CH2-COOH. Null ellipsometry, contact angle goniometry and infrared reflection-absorption spectroscopy are used to monitor the physical and chemical changes occurring within the SAMs upon acid post treatment; after incubation with acids present in the solution; and after incubation in aged acid containing solutions. The presence of acid has a positive effect on the crystallinity, packing and orientation of the supporting alkyl and ethylene glycol subunits of the SAM. Our studies also confirm previous findings stating that the carboxylic groups are rapidly converted into ethyl ester groups in the presence of hydrochloric acid in the incubation solution. It is also evident that the conversion occurs in the presence of the weaker acid, acetic acid, although at a much slower rate than for hydrochloric acid. This is a new observation that has not been reported on before. The physical and chemical characterization is also complemented with a functional bioaffinity study. The functional evaluation revealed that the present model system was surprisingly insensitive to the degree of esterification of the carboxylic acid SAMs, but that 4 weeks of storage of the two investigated thiols in hydrochloric acid containing ethanol resulted in SAMs that were completely inactive with respect to immobilization and subsequent binding of the antigen. It was encouraging to note that the non-specific binding of both antigen and antibody was extremely low on the two SAMs, regardless of the relative amount of ethyl esters on the surface.

    Ort, förlag, år, upplaga, sidor
    ACS, 2010
    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-19691 (URN)10.1021/la902255j (DOI)
    Tillgänglig från: 2009-07-14 Skapad: 2009-07-14 Senast uppdaterad: 2017-12-13Bibliografiskt granskad
    3. On the stability of carboxylic acid-terminated self-assembled monolayers: Influence of varying alkyl chain length
    Öppna denna publikation i ny flik eller fönster >>On the stability of carboxylic acid-terminated self-assembled monolayers: Influence of varying alkyl chain length
    Visa övriga...
    (Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    The physio-chemical properties and storage stability of three carboxyl-terminated selfassembled monolayers (SAMs), prepared from ethanolic and acidified ethanolic thiolssolutions of HS-(CH2)nCONH-EG6CH2-COOH, n=3, 11 or 15 on gold, have been correlated to their performance as potential biosensor surfaces. The SAMs of the two longer thiols (n=11, 15) prepared from acidified thiol solutions displayed highly organized and crystallinelike alkyl and ethylene glycol portions. The length of the supporting alkyl chain also influenced the storage stability of the SAMs in nitrogen gas, water and acidified water/ethanol solutions. The two long alkyl chain SAMs exhibited excellent storage characteristics, whereas the short chain thiol resulted in a less storage stable SAM as revealed by increased molecular decomposition and desorption, and a significantly reduced biofunctionality.

    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-19692 (URN)
    Tillgänglig från: 2009-07-14 Skapad: 2009-07-14 Senast uppdaterad: 2010-01-14Bibliografiskt granskad
    Ladda ner fulltext (pdf)
    Self Assembled Monolayers for Quartz Crystal Microbalance based Biosensing
    Ladda ner (pdf)
    Cover
  • 157.
    Myrskog, Annica
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Anderson, Henrik
    Attana AB, Björnnäsvägen 21, SE-114 19 Stockholm, Sweden/Uppsala University, Ångström Laboratory, Solid State Electronics, P.O. Box 534, SE-751 21 Uppsala, Sweden.
    Ingemarsson, Björn
    Attana AB, Björnnäsvägen 21, SE-114 19 Stockholm, Sweden.
    Liedberg, Bo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Esterification of self-assembled carboxylic acid-terminated thiolmonolayers in acid environment: A time dependent study2010Ingår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 26, nr 2, s. 821-829Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This contribution reports on the influence of acids on the quality of carboxylic acid terminated self-assembled monolayers (SAMs) on gold prepared from ethanolic solution of HS-(CH2)15-COOH and HS-(CH2)11CONH–(EG)6CH2-COOH. Null ellipsometry, contact angle goniometry and infrared reflection-absorption spectroscopy are used to monitor the physical and chemical changes occurring within the SAMs upon acid post treatment; after incubation with acids present in the solution; and after incubation in aged acid containing solutions. The presence of acid has a positive effect on the crystallinity, packing and orientation of the supporting alkyl and ethylene glycol subunits of the SAM. Our studies also confirm previous findings stating that the carboxylic groups are rapidly converted into ethyl ester groups in the presence of hydrochloric acid in the incubation solution. It is also evident that the conversion occurs in the presence of the weaker acid, acetic acid, although at a much slower rate than for hydrochloric acid. This is a new observation that has not been reported on before. The physical and chemical characterization is also complemented with a functional bioaffinity study. The functional evaluation revealed that the present model system was surprisingly insensitive to the degree of esterification of the carboxylic acid SAMs, but that 4 weeks of storage of the two investigated thiols in hydrochloric acid containing ethanol resulted in SAMs that were completely inactive with respect to immobilization and subsequent binding of the antigen. It was encouraging to note that the non-specific binding of both antigen and antibody was extremely low on the two SAMs, regardless of the relative amount of ethyl esters on the surface.

  • 158.
    Myrskog, Annica
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Ruželè, Živilè
    Department of Functional Nanomaterials, Institute of Physics, Savanoriu 231, LT-02300 Vilnius, Lithuania.
    Anderson, Henrik
    Attana AB, Björnnäsvägen 21, SE-114 19 Stockholm, Sweden/Uppsala University, Ångström Laboratory, Solid State Electronics, P.O. Box 534, SE-751 21 Uppsala, Sweden.
    Aastrup, Teodor
    Attana AB, Björnnäsvägen 21, SE-114 19 Stockholm, Sweden.
    Valiokas, Ramunas
    Department of Functional Nanomaterials, Institute of Physics, Savanoriu 231, LT-02300 Vilnius, Lithuania.
    Liedberg, Bo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    On the stability of carboxylic acid-terminated self-assembled monolayers: Influence of varying alkyl chain lengthManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    The physio-chemical properties and storage stability of three carboxyl-terminated selfassembled monolayers (SAMs), prepared from ethanolic and acidified ethanolic thiolssolutions of HS-(CH2)nCONH-EG6CH2-COOH, n=3, 11 or 15 on gold, have been correlated to their performance as potential biosensor surfaces. The SAMs of the two longer thiols (n=11, 15) prepared from acidified thiol solutions displayed highly organized and crystallinelike alkyl and ethylene glycol portions. The length of the supporting alkyl chain also influenced the storage stability of the SAMs in nitrogen gas, water and acidified water/ethanol solutions. The two long alkyl chain SAMs exhibited excellent storage characteristics, whereas the short chain thiol resulted in a less storage stable SAM as revealed by increased molecular decomposition and desorption, and a significantly reduced biofunctionality.

  • 159. Nilsson, S
    et al.
    Svedberg, M
    Pettersson, J
    Björefors, Fredrik
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Markides, K
    Nyholm, L
    Evaluations of the stability of sheathless electrospray ionization mass spectrometry emitters using electrochemical techniques2001Ingår i: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 73, nr 19, s. 4607-4616Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The processes that cause the failure of sheathless electrospray ionization (ESI) emitters, based on different kinds of gold coatings on fused-silica capillaries, are described and explained. The methods chosen for this study include electrochemical methods, ICPMS analysis of the electrolytes used, SEM studies, and electrospray experiments. Generally, the failure occurs by loss of the conductive coating. It is shown that emitters with sputter-coated gold lose their coatings because of mechanical stress caused by the gas evolution accompanying water oxidation or reduction. Emitters with gold coatings on top of adhesion layers of chromium and nickel alloy withstand this mechanical stress and have excellent durability when operating as cathodes. When operating as anodes, the adhesion layer is electrochemically dissolved through the gold film, and the gold film then flakes off. It is shown that the conductive coating behaves as a cathode even in the positive electrospray mode when the magnitude of a superimposed reductive electrophoretic current exceeds that of the oxidative electrospray current. Fairy-dust coatings developed in our laboratory (see Barnidge, D. R., et al. Anal. Chem. 1999, 71, 4115-4118) by gluing gold dust onto the emitter, are unaffected by the mechanical stress due to gas evolution. When oxidized, the fairy-dust coatings show an increased surface roughness and decreased conductivities due to the formation of gold oxide. The resistance of this oxide layer is however negligible in comparison with that of the gas phase in ESI. Furthermore, since no flaking and only negligible electrochemical etching of gold was found, practically unlimited emitter lifetimes may be achieved with fairy-dust coatings.

  • 160.
    Nugraha, Roni
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Finlay, John A.
    University of Birmingham, England.
    Hill, Sophie
    University of Birmingham, England.
    Fyrner, Timmy
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska högskolan.
    Yandi, Wetra
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär fysik. Linköpings universitet, Tekniska högskolan.
    Callow, Maureen E.
    University of Birmingham, England.
    Callow, James A.
    University of Birmingham, England.
    Ederth, Thomas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär fysik. Linköpings universitet, Tekniska högskolan.
    Antifouling properties of oligo(lactose)-based self-assembled monolayers2015Ingår i: Biofouling (Print), ISSN 0892-7014, E-ISSN 1029-2454, Vol. 31, nr 1, s. 123-134Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The antifouling (AF) properties of oligo(lactose)-based self-assembled monolayers (SAMs), using four different proteins, zoospores of the green alga Ulva linza and cells of the diatom Navicula incerta, were investigated. The SAM-forming alkylthiols, which contained 1, 2 or 3 lactose units, showed significant variation in AF properties, with no differences in wettability. Non-specific adsorption of albumin and pepsin was low on all surfaces. Adsorption of lysozyme and fibrinogen decreased with increasing number of lactose units in the SAM, in agreement with the generally observed phenomenon that thicker hydrated layers provide higher barriers to protein adsorption. Settlement of spores of U. linza followed an opposite trend, being greater on the bulkier, more hydrated SAMs. These SAMs are more ordered for the larger saccharide units, and it is therefore hypothesized that the degree of order, and differences in crystallinity or stiffness between the surfaces, is an important parameter regulating spore settlement on these surfaces.

    Ladda ner fulltext (pdf)
    fulltext
  • 161. Beställ onlineKöp publikationen >>
    Nygren, Patrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    De Novo Design and Characterization of Surface Binding Peptides - Steps toward Functional Surfaces2006Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The ability to create surfaces with well-defined chemical properties is a major research field. One possibility to do this is to design peptides that bind with a specific secondary structure to silica nanoparticles. The peptides discussed in this thesis are constructed to be random coil in solution, but are “forced” to become helical when adsorbed to the particles. The positively charged side-chains on the peptides strongly disfavor an ordered structure in solution due to electrostatic repulsion. When the peptides are introduced to the particles these charges will strongly favor the structure because of ion pair bonding between the peptide and the negatively charged nanoparticles. The peptide-nanoparticle system has been thoroughly investigated by systematic variations of the side-chains. In order to determine which factors that contributes to the induced structure, several peptides with different amino acid sequences have been synthesized. Factors that have been investigated include 1) the positive charge density, 2) distribution of positive charges, 3) negative charge density, 4) increasing hydrophobicity, 5) peptide length, and 6) by incorporating amino acids with different helix propensities. Moreover, pH dependence and the effect of different nanoparticle curvature have also been investigated. It will also be shown that the system can be modified to incorporate a catalytic site that is only active when the helix is formed. This research will increase our understanding of peptide-surface interactions and might be of importance for both nanotechnology and medicine.

    Delarbeten
    1. Induction of structure and function in a designed peptide upon adsorption on a silica nanoparticle
    Öppna denna publikation i ny flik eller fönster >>Induction of structure and function in a designed peptide upon adsorption on a silica nanoparticle
    2006 (Engelska)Ingår i: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 45, nr 48, s. 8169-8173Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    No abstrack available.

    Nyckelord
    Amino acids, catalysis, helical structures, nanoparticles, peptides
    Nationell ämneskategori
    Kemi
    Identifikatorer
    urn:nbn:se:liu:diva-14548 (URN)10.1002/anie.200600965 (DOI)
    Tillgänglig från: 2008-02-25 Skapad: 2008-02-25 Senast uppdaterad: 2017-12-13Bibliografiskt granskad
    2. Optimizing Nanoparticle Induced Helical Structure in a De Novo Designed Peptide by Rational Changes in Amino Acid Sequence
    Öppna denna publikation i ny flik eller fönster >>Optimizing Nanoparticle Induced Helical Structure in a De Novo Designed Peptide by Rational Changes in Amino Acid Sequence
    Manuskript (Övrigt vetenskapligt)
    Identifikatorer
    urn:nbn:se:liu:diva-14549 (URN)
    Tillgänglig från: 2008-02-25 Skapad: 2008-02-25 Senast uppdaterad: 2010-01-13
    Ladda ner fulltext (pdf)
    FULLTEXT01
    Ladda ner (pdf)
    COVER01
  • 162. Beställ onlineKöp publikationen >>
    Nygren, Patrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Structural and Functional Studies of De Novo Designed Peptides at Surfaces2008Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The work presented in this thesis deals with the structural and functional properties of peptides at surfaces. The interaction of peptides with surfaces is an ever so common occurrence in our every day life, from the bug squashed on the windshield of our car to the barnacle on our boat, and from the blood plasma used in the hospital to the proteins in our cells. The effect these occurrences has on our lives is diverse, the bug is annoying whereas the barnacle settlement of ship hull is costly for marine transportation, the blood plasma contains components of vital importance for our immunological defense system and the proteins in our cells are crucial for regulatory processes and life.One part of this thesis, performed as a part of the EU-founded project AMBIO, deals with the concept of marine biofouling. A number of short peptides have been designed, synthesized, and used to investigate their effect on the settlement on marine biofoulers, such as the Ulva linza algae and the Navicula diatom, on template surfaces coated with thin layers of these molecules. The surfaces have been thoroughly investigated with respect of their physio-chemical properties before and after submersion in artificial seawater and ultimately in suspensions containing the organisms. The most interesting results were obtained with an arginine-rich peptide coating that when introduced to Ulva linza zoospores, displayed extensive settlement, compared to reference surfaces. In addition, a large fraction of the settled spores had an abnormal morphology.The other part of this thesis is focused on designed peptides that when adsorbed on a negatively charged surface adopts a well-defined secondary structure, either α-helical or β-sheet. Precisely placed amino acids in the peptides will strongly disfavor structure in solution, primarily due to electrostatic repulsion, but when the peptides are adsorbed on the negatively charged surfaces, they adopt a well-defined secondary structure due to ion pair bonding. These interactions have been thoroughly investigated by systematic variations of the side-chains. In order to determine the factors contributing to the induced structure, several peptides with different amino acid sequences have been synthesized. Factors that have been investigated include 1) the positive charge density, 2) distribution of positive charges, 3) negative charge density, 4) increasing hydrophobicity, and 5) incorporating amino acids with different helix propensities. Moreover, pH dependence and the effect of different interaction partners have also been investigated. It has also been shown that the system can be modified to incorporate a catalytic site that is only active when the helix is formed. This research will increase our understanding of peptide-surface interactions and might be of importance for both bionanotechnology and medicine.

    Delarbeten
    1. Induction of structure and function in a designed peptide upon adsorption on a silica nanoparticle
    Öppna denna publikation i ny flik eller fönster >>Induction of structure and function in a designed peptide upon adsorption on a silica nanoparticle
    2006 (Engelska)Ingår i: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 45, nr 48, s. 8169-8173Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    No abstrack available.

    Nyckelord
    Amino acids, catalysis, helical structures, nanoparticles, peptides
    Nationell ämneskategori
    Kemi
    Identifikatorer
    urn:nbn:se:liu:diva-14548 (URN)10.1002/anie.200600965 (DOI)
    Tillgänglig från: 2008-02-25 Skapad: 2008-02-25 Senast uppdaterad: 2017-12-13Bibliografiskt granskad
    2. Fundamental Design Principles That Guide Induction of Helix upon Formation of Stable Peptide−Nanoparticle Complexes
    Öppna denna publikation i ny flik eller fönster >>Fundamental Design Principles That Guide Induction of Helix upon Formation of Stable Peptide−Nanoparticle Complexes
    2008 (Engelska)Ingår i: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 8, nr 7, s. 1844-1852Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    We have shown that it is possible to design a peptide that has a very low helical content when free in solution but that adopts a well-defined helix when interacting with silica nanoparticles. From a systematic variation of the amino acid composition and distribution in designed peptides, it has been shown that the ability to form helical structure upon binding to the silica surface is dominated by two factors. First, the helical content is strongly correlated with the net positive charge on the side of the helix that interacts with the silica, and arginine residues are strongly favored over lysine residues in these positions. The second important factor is to have a high net negative charge on the side of the helix that faces the solution. Apparently, both attractive and repulsive electrostatic forces dominate the induction and stabilization of a bound helix. It is also evident that using amino acids that have high propensity to form helix in solution are also advantageous for the formation of helix on surfaces.

    Nationell ämneskategori
    Annan medicinsk grundvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-15015 (URN)10.1021/nl080386s (DOI)
    Tillgänglig från: 2008-10-09 Skapad: 2008-10-09 Senast uppdaterad: 2018-01-12Bibliografiskt granskad
    3. Secondary Structure in de Novo Designed Peptides Induced by Electrostatic Interaction with a Lipid Bilayer Membrane
    Öppna denna publikation i ny flik eller fönster >>Secondary Structure in de Novo Designed Peptides Induced by Electrostatic Interaction with a Lipid Bilayer Membrane
    Visa övriga...
    2010 (Engelska)Ingår i: LANGMUIR, ISSN 0743-7463, Vol. 26, nr 9, s. 6437-6448Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    We show that it is possible to induce a defined secondary structure in de nova designed peptides upon electrostatic attachment to negatively charged lipid bilayer vesicles without partitioning of the peptides into the membrane, and that the secondary structure can be varied via small changes in the primary amino acid sequence of the peptides. The peptides have a random-coil conformation in solution, and results from far-UV circular dichroism spectroscopy demonstrate that the structure induced by the interaction with silica nanoparticles is solely alpha-helical and also strongly pH-dependent. The present study shows that negatively charged vesicles, to which the peptides are electrostatically adsorbed via cationic amino acid residues, induce either alpha-helices or beta-sheets and that the conformation is dependent on both lipid composition and variations in peptide primary structure. The pH-dependence of the vesicle-induced peptide secondary structure is weak, which correlates well with small differences in the vesicles electrophoretic mobility, and thus the surface charge, as the pH is varied.

    Ort, förlag, år, upplaga, sidor
    ACS American Chemical Society, 2010
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-56297 (URN)10.1021/la100027n (DOI)000276969700056 ()
    Anmärkning

    The previous status of this article was Manuscript.

    Tillgänglig från: 2010-05-07 Skapad: 2010-05-07 Senast uppdaterad: 2017-01-11
    4. Anomalous settlement behavior of Ulva linza zoospores on cationic oligopeptide surfaces
    Öppna denna publikation i ny flik eller fönster >>Anomalous settlement behavior of Ulva linza zoospores on cationic oligopeptide surfaces
    Visa övriga...
    2008 (Engelska)Ingår i: Biofouling (Print), ISSN 0892-7014, E-ISSN 1029-2454, Vol. 24, nr 4, s. 303-312Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Identification of settlement cues for marine fouling organisms opens up new strategies and methods for biofouling prevention, and enables the development of more effective antifouling materials. To this end, the settlement behaviour of zoospores of the green alga Ulva linza onto cationic oligopeptide self-assembled monolayers (SAMs) has been investigated. The spores interact strongly with lysine- and arginine-rich SAMs, and their settlement appears to be stimulated by these surfaces. Of particular interest is an arginine-rich oligopeptide, which is effective in attracting spores to the surface, but in a way which leaves a large fraction of the settled spores attached to the surface in an anomalous fashion. These 'pseudo-settled' spores are relatively easily detached from the surface and do not undergo the full range of cellular responses associated with normal commitment to settlement. This is a hitherto undocumented mode of settlement, and surface dilution of the arginine-rich peptide with a neutral triglycine peptide demonstrates that both normal and anomalous settlement is proportional to the surface density of the arginine-rich peptide. The settlement experiments are complemented with physical studies of the oligopeptide SAMs, before and after extended immersion in artificial seawater, using infrared spectroscopy, null ellipsometry and contact angle measurements.

    Nyckelord
    Fouling, algae, self-assembled monolayers, cationic peptides, Ulva, spore
    Nationell ämneskategori
    Fysikalisk kemi
    Identifikatorer
    urn:nbn:se:liu:diva-15018 (URN)10.1080/08927010802192650 (DOI)
    Tillgänglig från: 2008-10-09 Skapad: 2008-10-09 Senast uppdaterad: 2017-12-11
    5. Interactions of Zoospores of Ulva linza with Arginine-Rich Oligopeptide Monolayers
    Öppna denna publikation i ny flik eller fönster >>Interactions of Zoospores of Ulva linza with Arginine-Rich Oligopeptide Monolayers
    Visa övriga...
    2009 (Engelska)Ingår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 25, nr 16, s. 9375-9383Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    We recently reported oil the strong interactions of zoospores of the green alga, Ulva linza with all arginine-rich oligopeptide self-assembled monolayer (SAM) [Biofouling 2008, 24, 303-312], where the arginine-rich peptide induced not only high spore settlement, but also a form of abnormal settlement, or "pseudo-settlement", whereby it proportion of spores do not go through the normal process of surface exploration, adhesive exocytosis, and loss of flagella. Further. it was demonstrated that both the total number of settled spores and the fraction of pseudosettled spores were related to the surface density of the arginine-rich peptide. Here we present a further investigation of the interactions of zoospores of ulva with a set of oligomeric, de nom designed, arginine-rich peptides, specifically aimed to test the effect of peptide primary structure on the interaction. Via variations in the peptide length and by permutations in the amino acid sequences, we gain further insight into the spore-surface interactions. The interpretation of the biological assays is supported by physicochemical characterization of the SAMs using infrared spectroscopy, ellipsometry, and contact angle measurement. Results confirm the importance of arginine residues for the anomalous pseudosettlement, and we found that settlement is modulated by variations in both the total length and peptide primary structure. To elucidate the Causes of the anomalous settlement and the possible relation to peptide-membrane interactions, we also compared the settlement of the "naked" zoospores of Ulva(which present it lipoprotein membrane to the exterior without a discrete polysaccharide cell wall), with the settlement of diatoms (unicellular algae that are surrounded by it silica cell wall), onto the peptide SAMs. Cationic SAMs do not notably affect settlement (attachment), adhesion strength, or viability of diatom cells, Suggesting that the effect of the peptides on zoospores of Ulva is mediated via specific peptide-membrane interactions.

    Ort, förlag, år, upplaga, sidor
    American Chemical Society (ACS), 2009
    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-19996 (URN)10.1021/la900688g (DOI)
    Anmärkning

    The previous status of this article was Manuscript.

    Tillgänglig från: 2009-08-24 Skapad: 2009-08-24 Senast uppdaterad: 2017-12-13Bibliografiskt granskad
    Ladda ner fulltext (pdf)
    FULLTEXT01
    Ladda ner (pdf)
    COVER01
  • 163.
    Nygren, Patrik
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Lundqvist, Martin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär Bioteknik. Linköpings universitet, Tekniska högskolan.
    Broo, Klas
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    Jonsson, Bengt-Harald
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär Bioteknik. Linköpings universitet, Tekniska högskolan.
    Fundamental Design Principles That Guide Induction of Helix upon Formation of Stable Peptide−Nanoparticle Complexes2008Ingår i: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 8, nr 7, s. 1844-1852Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We have shown that it is possible to design a peptide that has a very low helical content when free in solution but that adopts a well-defined helix when interacting with silica nanoparticles. From a systematic variation of the amino acid composition and distribution in designed peptides, it has been shown that the ability to form helical structure upon binding to the silica surface is dominated by two factors. First, the helical content is strongly correlated with the net positive charge on the side of the helix that interacts with the silica, and arginine residues are strongly favored over lysine residues in these positions. The second important factor is to have a high net negative charge on the side of the helix that faces the solution. Apparently, both attractive and repulsive electrostatic forces dominate the induction and stabilization of a bound helix. It is also evident that using amino acids that have high propensity to form helix in solution are also advantageous for the formation of helix on surfaces.

  • 164.
    Nygren, Patrik
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Lundqvist, Martin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär Bioteknik. Linköpings universitet, Tekniska högskolan.
    Liedberg, Bo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Broo, Klas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär Bioteknik. Linköpings universitet, Tekniska högskolan.
    Jonsson, Bengt-Harald
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär Bioteknik. Linköpings universitet, Tekniska högskolan.
    Ederth, Thomas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Secondary structure in de novo designed peptides induced by electrostatic interaction with particles and membranes.2011Konferensbidrag (Övrigt vetenskapligt)
    Ladda ner fulltext (pdf)
    fulltext
  • 165.
    Nygren, Patrik
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Lundqvist, Martin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär Bioteknik. Linköpings universitet, Tekniska högskolan.
    Liedberg, Bo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Jonsson, Bengt-Harald
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär Bioteknik. Linköpings universitet, Tekniska högskolan.
    Ederth, Thomas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Secondary Structure in de Novo Designed Peptides Induced by Electrostatic Interaction with a Lipid Bilayer Membrane2010Ingår i: LANGMUIR, ISSN 0743-7463, Vol. 26, nr 9, s. 6437-6448Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We show that it is possible to induce a defined secondary structure in de nova designed peptides upon electrostatic attachment to negatively charged lipid bilayer vesicles without partitioning of the peptides into the membrane, and that the secondary structure can be varied via small changes in the primary amino acid sequence of the peptides. The peptides have a random-coil conformation in solution, and results from far-UV circular dichroism spectroscopy demonstrate that the structure induced by the interaction with silica nanoparticles is solely alpha-helical and also strongly pH-dependent. The present study shows that negatively charged vesicles, to which the peptides are electrostatically adsorbed via cationic amino acid residues, induce either alpha-helices or beta-sheets and that the conformation is dependent on both lipid composition and variations in peptide primary structure. The pH-dependence of the vesicle-induced peptide secondary structure is weak, which correlates well with small differences in the vesicles electrophoretic mobility, and thus the surface charge, as the pH is varied.

  • 166.
    Pearce, Ruth
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik. Linköpings universitet, Tekniska fakulteten.
    Yakimova, Rositsa
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Eriksson, Johan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Yt- och Halvledarfysik. Linköpings universitet, Tekniska högskolan.
    Hultman, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Andersson, Mike
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Lloyd Spetz, Anita
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik. Linköpings universitet, Tekniska högskolan.
    Development of FETs and resistive devices based on epitaxially grown single layer graphene on SiC for highly sensitive gas detection2012Ingår i: Materials Science Forum Vols 717 - 720, Trans Tech Publications Inc., 2012, Vol. 717-720, s. 687-690Konferensbidrag (Refereegranskat)
    Abstract [en]

    Epitaxially grown single layer graphene on silicon carbide (SiC) resistive sensors were characterised for NO2 response at room and elevated temperatures, with an n-p type transition observed with increasing NO2 concentration for all sensors. The concentration of NO2 required to cause this transition varied for different graphene samples and is attributed to varying degrees of substrate induced Fermi-level (E-F) pinning above the Dirac point. The work function of a single layer device increased steadily with increasing NO2 concentration indicating no change in reaction mechanism for high and low concentrations despite a change in sensor response direction. Epitaxially grown graphene device preparation is challenging due to poor adhesion of the graphene layer to the substrate. A field effect transistor (FET) device is presented which does not require wire bonding to contacts on graphene.

  • 167.
    Pedersen, Henrik
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Söderlind, Fredrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    Petoral, Rodrigo M.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Uvdal, Kajsa
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Käll, Per-Olov
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Fysikalisk Kemi. Linköpings universitet, Tekniska högskolan.
    Ojamäe, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Fysikalisk Kemi. Linköpings universitet, Tekniska högskolan.
    Surface interactions between Y2O3 nanocrystals and organic molecules—an experimental and quantum-chemical study2005Ingår i: Surface Science, ISSN 0039-6028, E-ISSN 1879-2758, Vol. 592, nr 1-3, s. 124-140Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

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

  • 168.
    Petoral, Rodrigo Jr
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Uvdal, Kajsa
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Chemisorption of Aromatic Amino Acid Derivatives on Gold Surfaces2003Ingår i: AVS 2003,2003, 2003Konferensbidrag (Övrigt vetenskapligt)
  • 169.
    Petoral, Rodrigo Jr
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Uvdal, Kajsa
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    NEXAFS study of amino acid analogues assembled on gold2003Ingår i: XAFS12,2003, 2003Konferensbidrag (Övrigt vetenskapligt)
  • 170.
    Petoral, Rodrigo Jr
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Uvdal, Kajsa
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    NEXAFS study of amino acid analogues assembled on gold2005Ingår i: Physica scripta. T, ISSN 0281-1847, Vol. T115, s. 851-854Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 171.
    Petoral, Rodrigo Jr
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Uvdal, Kajsa
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Structural investigation of t-butyl carbamate-thiol chemisorbed on gold2005Ingår i: EuCheMS,2005, 2005Konferensbidrag (Refereegranskat)
  • 172.
    Petoral, Rodrigo Jr
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Wermelin, Karin
    Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för klinisk och experimentell medicin, Ortopedi och idrottsmedicin.
    Dahlstedt, E.
    Hellberg, J.
    Uvdal, Kajsa
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Adsorption of n-butyl-substituted tetrathiafulvalene dodecanethiol on gold2005Ingår i: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 287, nr 2, s. 388-393Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 173.
    Petoral, Rodrigo Jr
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Yazdi, Gholamreza
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Materiefysik.
    Vahlberg, Cecilia
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Syväjärvi, Mikael
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Materiefysik.
    Lloyd Spetz, Anita
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik.
    Uvdal, Kajsa
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Yakimova, Rositsa
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Materiefysik.
    Surface Functionalization of SiC for Biosensor Applications2007Ingår i: ECSCRM 2006,2006, Material Science Forum, vol 556-557: Trans Tech Publications , 2007, s. 957-Konferensbidrag (Refereegranskat)
  • 174.
    Petoral, Rodrigo M
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär ytfysik och nanovetenskap. Linköpings universitet, Tekniska fakulteten.
    Söderlind, Fredrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    Klasson, Anna
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiologi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Bildmedicinskt centrum, Röntgenkliniken i Linköping.
    Suska, Anke
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik. Linköpings universitet, Tekniska fakulteten.
    Fortin, Marc-André
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär ytfysik och nanovetenskap. Linköpings universitet, Tekniska fakulteten.
    Abrikossova, Natalia
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär ytfysik och nanovetenskap. Linköpings universitet, Tekniska fakulteten.
    Selegard, Linnea
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Käll, Per-Olov
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Fysikalisk Kemi. Linköpings universitet, Tekniska högskolan.
    Engström, Maria
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiologi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Bildmedicinskt centrum, Röntgenkliniken i Linköping.
    Uvdal, Kajsa
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär ytfysik och nanovetenskap. Linköpings universitet, Tekniska fakulteten.
    Synthesis and Characterization of Tb3+-Doped Gd2O3 Nanocrystals: A Bifunctional Material with Combined Fluorescent Labeling and MRI Contrast Agent Properties2009Ingår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 113, nr 17, s. 6913-6920Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 175.
    Petrone, Luigi
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Molecular surface chemistry in marine bioadhesion2013Ingår i: Advances in Colloid and Interface Science, ISSN 0001-8686, E-ISSN 1873-3727, Vol. 195-196, s. 1-18Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This review covers the in situ molecular physicochemical characterisation of bioadhesives at solid/liquid interfaces, with the aim of elucidating the adhesion strategies that lie at the root of marine biofouling. It focuses on three major foulers: mussels, algae and barnacles. The dispersal of these organisms, their colonisation of surfaces, and ultimately their survival rely critically on the ability of the organisms larvae or spores to locate a favourable settlement site and undergo metamorphosis, thus initiating their sessile existence. Differences in the composition of adhesive secretions and the strategies employed for their temporary or permanent implementation exists between the larval and adult life stages. To date, only a few adhesive secretions from marine fouling organisms have been adequately described in terms of their chemical composition, and a survey revealed the presence of certain recurrent functional groups, specifically catechol, carboxylate, monoester-sulphate and -phosphate. This review will describe the binding modes of such functionalities to wet mineral/metal oxides surfaces. Such functionalities will be ranked based on their ability to bind to hydrophilic surfaces replacing surface-bound water (Langmuir adsorption constant) as well as other adsorbates (competitive adsorption). A plausible explanation for the propensity of the reviewed adhesive functionalities to bind to hydrous metal oxide surfaces will be given on the basis of the Hard and Soft Acids and Bases principle, Hofmeister effects and entropic considerations. From the in situ analysis of marine organism bioadhesives and adsorption studies of functionalities relevant to the bioadhesion process, insights can be gleaned for a knowledge-based innovation of antifouling strategies and the synthesis of strong, durable adhesive materials, which are suitable for implementation in wet environments.

  • 176.
    Piehler, J.
    et al.
    Institut Für Physikalische Chemie, Auf der Morgenstelle 8, D-72076 Tübingen, Germany, Lehrstuhl Für Zelluläre Biochemie und Biophysik, Karl-von-Frisch-Strasse 1, 35033 Marburg, Germany.
    Brecht, A.
    Institut Für Physikalische Chemie, Auf der Morgenstelle 8, D-72076 Tübingen, Germany.
    Valiokas, Ramunas
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Liedberg, Bo
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Gauglitz, G.
    Institut Für Physikalische Chemie, Auf der Morgenstelle 8, D-72076 Tübingen, Germany.
    A high-density poly(ethylene glycol) polymer brush for immobilization on glass-type surfaces2000Ingår i: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 15, nr 9-10, s. 473-481Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Label-free heterogeneous phase detection critically depends on the properties of the interfacial layer. We have obtained high-density monomolecular poly(ethylene glycol) (PEG) layers by solvent-free coupling of homo-bifunctional PEGs (2000 g/mol) at 75°C to silica surfaces silanized with glycidyloxipropyltrimethoxysilane (GOPTS). Characterization by ellipsometry and contact angles revealed that PEG layers up to 3.4 ng/mm2 with low roughness and flexibility were obtained. Specific and non-specific binding at these PEG surfaces was monitored by reflectometric interference spectroscopy (RIfS). No significant non-specific adsorption upon incubation of 1 mg/ml ovalbumin was detectable ( < 10 pg/mm2), and 150 pg/mm2 upon incubation of 10% calf serum, less than 10% of the amount adsorbed to the solely silanized surfaces. The terminal functional groups of the PEG layers were utilized to couple ligands and a protein. Specific protein interaction with these immobilized compounds was detected with saturation loadings in the range of protein monolayers (2-4 ng/mm2). The excellent functional properties, the high stability of the layers, the generic and practical coupling procedure and the versatility for immobilizing compounds of very different functionality make these PEG layers very attractive for application in label-free detection with silica or metal-oxide based transducers. (C) 2000 Elsevier Science S.A.Label-free heterogeneous phase detection critically depends on the properties of the interfacial layer. We have obtained high-density monomolecular poly(ethylene glycol) (PEG) layers by solvent-free coupling of homo-bifunctional PEGs (2000 g/mol) at 75 °C to silica surfaces silanized with glycidyloxipropyltrimethoxysilane (GOPTS). Characterization by ellipsometry and contact angles revealed that PEG layers up to 3.4 ng/mm2 with low roughness and flexibility were obtained. Specific and non-specific binding at these PEG surfaces was monitored by reflectometric interference spectroscopy (RIfS). No significant non-specific adsorption upon incubation of 1 mg/ml ovalbumin was detectable (<10 pg/mm2), and 150 pg/mm2 upon incubation of 10% calf serum, less than 10% of the amount adsorbed to the solely silanized surfaces. The terminal functional groups of the PEG layers were utilized to couple ligands and a protein. Specific protein interaction with these immobilized compounds was detected with saturation loadings in the range of protein monolayers (2-4 ng/mm2). The excellent functional properties, the high stability of the layers, the generic and practical coupling procedure and the versatility for immobilizing compounds of very different functionality make these PEG layers very attractive for application in label-free detection with silica or metal-oxide based transducers.

  • 177.
    Rafat, Mehrdad
    et al.
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelningen för cellbiologi. Linköpings universitet, Hälsouniversitetet.
    Koh, Li Buay
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Islam, Mohammad Mirazul
    Linköpings universitet, Institutionen för klinisk och experimentell medicin. Linköpings universitet, Hälsouniversitetet.
    Liedberg, Bo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Griffith, May
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelningen för cellbiologi. Linköpings universitet, Hälsouniversitetet.
    Highly elastic epoxycross‐linked collagen hydrogels for corneal tissueengineering2012Ingår i: Acta Ophthalmologica; Special Issue: Abstracts from the 2012 European Association for Vision and Eye Research Conference, Volume 90, Issue Supplement s249, page 0, September 2012, John Wiley & Sons, 2012Konferensbidrag (Refereegranskat)
    Abstract [en]

    Purpose Our objective is to develop novel materials that support the regeneration of diseased or damaged corneas. Despite the promising clinical results that we previously reported on biosynthetic corneas, more robust and elastic materials are required to withstand the adverse host conditions faced for high risk transplantation in severely damaged or diseased corneas. This presentation will provide details on an epoxy cross-linked collagen-based scaffold with enhanced mechanical properties.

    Methods We have developed a range of collagen-based materials as mimics of the cell-free corneal stromal extracellular matrix. In this study, cross-linked polymer networks of collagen hydrogels were prepared using a hybrid of 1,4-butanediol diglycidyl ether (BDDGE) and carbodiimides (e.g. EDC-NHS) as cross-linkers. Briefly, 10w/w% porcine collagen type I was mixed in a T-piece system at various compositions and pH, e.g. pH 5, pH 11, and incorporated with laminin adhesive peptides (YIGSR, and IKVAV). Promising material formulations were tested for their physiochemical properties (e.g. mechanical, optical, water uptake, FTIR, and thermal degradation) and physiological properties (e.g. interactions with corneal cells, and biodegradation).

    Results The hybrid BDDGE hydrogels demonstrated improved mechanical properties and degree of cross-linking while maintaining their optical clarity and biocompatibility compared to controls (e.g. EDC/NHS-crosslinked hydrogels). Incorporation of laminin-derived cell-adhesive peptide (IKVAV) demonstrated significant increase in corneal cells (HCECs) proliferation compared to controls.

    Conclusion The hybrid BDDGE-crosslinked collagen-based hydrogels have the potential for use as tissue-engineered corneal substitutes.

  • 178.
    Rafat, Mehrdad
    et al.
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelningen för cellbiologi. Linköpings universitet, Hälsouniversitetet.
    Mondal, Debasish
    Linköpings universitet, Institutionen för klinisk och experimentell medicin. Linköpings universitet, Hälsouniversitetet.
    Islam, M.
    Linköpings universitet, Institutionen för klinisk och experimentell medicin. Linköpings universitet, Hälsouniversitetet.
    Liedberg, Bo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Griffith, May
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelningen för cellbiologi. Linköpings universitet, Hälsouniversitetet.
    Nanoparticles incorporated collagen hydrogels for sustained release of EGF2013Ingår i: Acta Ophthalmologica; Special Issue: Abstracts from the 2013 European Association for Vision and Eye Research Conference, Volume 91, Issue Supplement s252, page 0, August 2013, John Wiley & Sons, 2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    Therapeutic biomolecules such as growth factors are essential for enhancing the regeneration of damaged tissues by inducing cell signaling activities such as cell migration, proliferation, and differentiation. Nevertheless, they have short half-lives in physiological conditions due to fast deactivation and degradation by enzymes and other physical and chemical reactions. Therefore, there is a great need for the suitable target delivery of nanoparticles to improve the release kinetics of growth factors as well as their therapeutic effectiveness. The main objective of this study was to develope and characterize a sustained delivery system consisting of an EGF-encapslated chitosan nanoparticles and collagen hydrogel carrier system to achieve a sustained release of EGF. In this study, we made EGF-loaded chitosan nanoparticles, which could be incorporated into an engineered collagen hydrogel scaffold. The particles were spherical in the size range of 60–100 nm. The release kinetics of EGF showed the release of growth factors in a sustained manner. Live-dead staining of human corneal epithelial (HCEC) cells was done to evaluate the cytotoxicity of the nanoparticles.

  • 179.
    Rakickas, T.
    et al.
    Department of Functional Nanomaterials, Institute of Physics, Savanoriu¸ 231, LT-02300 Vilnius, Lithuania.
    Gavutis, M.
    Department of Functional Nanomaterials, Institute of Physics, Savanoriu¸ 231, LT-02300 Vilnius, Lithuania.
    Reichel, A.
    Institute of Biochemistry and Cluster of Excellence Macromolecular Complexes (CEF), Johann Wolfgang Goethe-University, Max-von-Laue-Strasse 9, 60438 Frankfurt, Germany.
    Piehler, J.
    Institute of Biochemistry and Cluster of Excellence Macromolecular Complexes (CEF), Johann Wolfgang Goethe-University, Max-von-Laue-Strasse 9, 60438 Frankfurt, Germany.
    Liedberg, Bo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Valiokas, R.
    Department of Functional Nanomaterials, Institute of Physics, Savanoriu¸ 231, LT-02300 Vilnius, Lithuania.
    Protein-Protein Interactions in Reversibly Assembled Nanopatterns2008Ingår i: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 8, nr 10, s. 3369-3375Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We describe herein a platform to study protein-protein interactions and to form functional protein complexes in nanoscopic surface domains. For this purpose, we employed multivalent chelator (MCh) templates, which were fabricated in a stepwise procedure combining dip-pen nanolithography (DPN) and molecular recognition-directed assembly. First, we demonstrated that an atomic force microscope (AFM) tip inked with an oligo(ethylene glycol) (OEG) disulfide compound bearing terminal biotin groups can be used to generate biotin patterns on gold achieving line widths below 100 nm, a generic platform for fabrication of functional nanostructures via the highly specific biotin-streptavidin recognition. Subsequently, we converted such biotin/streptavidin patterns into functional MCh patterns for reversible assembly of histidine- tagged (His-tagged) proteins via the attachment of a tris-nitriloacetic acid (trisNTA) biotin derivative. Fluorescence microscopy confirmed reversible immobilization of the receptor subunit ifnar2-His10 and its interaction with interferon-a2 labeled with fluorescent quantum dots in a 7 × 7 dot array consisting of trisNTA spots with a diameter of ~230 nm. Moreover, we carried out characterization of the specificity, stability, and reversibility as well as quantitative real-time analysis of protein-protein interactions at the fabricated nanopatterns by imaging surface plasmon resonance. Our work offers a route for construction and analysis of functional protein-based nanoarchitectures. © 2008 American Chemical Society.

  • 180.
    Rakickas, Tomas
    et al.
    Centre for Physics Science and Technology, Vilnius.
    Ericsson, Emma
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär fysik. Linköpings universitet, Tekniska fakulteten.
    Ruzele, Zivile
    Centre for Physics Science and Technology, Vilnius.
    Liedberg, Bo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Valiokas, Ramunas
    Centre for Physics Science and Technology, Vilnius.
    Functional Hydrogel Density Patterns Fabricated by Dip-Pen Nanolithography and Photografting2011Ingår i: SMALL, ISSN 1613-6810, Vol. 7, nr 15, s. 2153-2157Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    n/a

  • 181. Riepl, M
    et al.
    Enander, Karin
    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.
    Schäfering, Michael
    Thermo Hybaid Interactiva GmbH.
    Kruschina, Margit
    Thermo Hybaid Interactiva GmbH.
    Ortigao, Flavio
    Thermo Hybaid Interactiva GmbH.
    Functionalized surfaces of mixed alkanethiols on gold as a platform for oligonucleotide microarrays2002Ingår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 18, nr 18, s. 7016-7023Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Mixed self-assembled monolayers of biotinylated- and ethylene glycol-terminated long-chain alkanethiols were prepared on gold surfaces in an attempt to develop a reliable protocol for immobilization of streptavidin. A broad range of surface analytical techniques including ellipsometry, atomic force microscopy, and infrared, fluorescence, and X-ray photoelectron spectroscopy were used to characterize the SAMs before and after immobilization of streptavidin. The first part of the work was focused on finding the mixing conditions that lead to optimum binding capacity of streptavidin. Mixed SAMs prepared from loading solutions containing 75-95% of the biotinylated alkanethiol resulted in high immobilization levels of functional streptavidin. The thin layers of streptavidin subsequently can be used for the immobilization of a broad spectrum of biotinylated biomolecules (e.g. oligonucleotides, cDNA, peptides, proteins, antibodies, and carbohydrates) and provides therefore an excellent platform for the fabrication of chips/arrays for biosensor and screening applications. This is successfully demonstrated by monitoring the hybridization between a biotinylated 24-mer capturing oligonucleotide and a labeled target 89-mer DNA using a fluorescence-based DNA-microarray detection system. Moreover, the DNA-microarray experiments also revealed (i) good selectivity when comparing the response of the complementary oligonucleotide with that of a random 24-mer capturing oligonucleotide and (ii) low levels of nonspecific binding to the streptavidin surface.

  • 182. Riepl, M.
    et al.
    Östblom, Mattias
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Lundström, Ingemar
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik.
    Svensson, S.C.T.
    Van, Der Gon A.W.D.
    Van Der Gon, A.W.D., Advalytix AG, Eugen-Sänger-Ring 4, D-85649 Brunnthal-Nord, Germany, Faculty of Applied Physics, Eindhoven University of Technology, 5600 MB Eindhoven, Netherlands.
    Schaferling, M.
    Liedberg, Bo
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Molecular gradients: An efficient approach for optimizing the surface properties of biomaterials and biochips2005Ingår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 21, nr 3, s. 1042-1050Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A variety of molecular gradients of alkanethiols with the structure HS-(CH2)m-X (m = 15, X = COOH, CH2NH 2, or CH3) and oligo(ethylene glycol)-terminated alkanethiols with the structures HS-(CH2)15-CO-NH-Eg n (n = 2, 4, or 6), HS-(CH2)15-CO-NH-Eg 2-(CH2)2-NH-CO-(CH2) 4-biotin, and HS-(CH2)15-CO-NH-Eg 6-CH2-COOH were prepared on polycrystalline gold films. These gradients were designed to serve as model surfaces for fundamental studies of protein adsorption and immobilization phenomena. Ellipsometry, infrared spectroscopy, and X-ray photoelectron spectroscopy, operating in scanning mode, were used to monitor the layer composition, gradient profiles, tail group conformation, and overall structural quality of the gradient assemblies. The gradient profiles were found to be 4-10 mm wide, and they increased in width with increasing difference in molecular complexity between the thiols used to form the gradient. The oligo(ethylene glycol) thiols are particularly interesting because they can be used to prepare so-called conformational gradients, that is, gradients that display a variation in oligo(ethylene glycol) chain conformation from all trans on the extreme Eg 2,4 sides, via an amorphous-like phase in the mixing regimes, to helical at the extreme Eg6 sides. We demonstrate herein a series of experiments where the above gradients are used to evaluate nonspecific binding of the plasma protein fibrinogen, and in agreement with previous studies, the highest amounts of nonspecifically bound fibrinogen were observed on all-trans monolayers, that is, on the extreme Eg2,4 sides. Moreover, gradients between Eg2 and a biotinylated analogue have been prepared to optimize the conditions for the immobilization of streptavidin. Ellipsometry and infrared spectroscopy reveal high levels of immobilization over a fairly broad range of compositions in the gradient regime, with a maximum between 50 and 60% of the biotinylated analogue in the monolayer. A pi gradient composed of (NH3+/COO-)-terminated thiols was also prepared and evaluated with respect to its ability to separate differently charged proteins, pepsin, and lysozyme, on a solid surface.

  • 183.
    Roder, Friedrich
    et al.
    University of Osnabruck.
    Waichman, Sharon
    University of Osnabruck.
    Paterok, Dirk
    University of Osnabruck.
    Schubert, Robin
    University of Osnabruck.
    Richter, Christian
    University of Osnabruck.
    Liedberg, Bo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Piehler, Jacob
    University of Osnabruck.
    Reconstitution of Membrane Proteins into Polymer-Supported Membranes for Probing Diffusion and Interactions by Single Molecule Techniques2011Ingår i: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 83, nr 17, s. 6792-6799Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We have established a robust and versatile analytical platform for probing membrane protein function in a defined lipid environment on solid supports. This approach is based on vesicle capturing onto an ultrathin poly(ethylene glycol) (PEG) polymer brush functionalized with fatty acid moieties and subsequent vesicle fusion into a contiguous membrane. In order to ensure efficient formation of these tethered polymer-supported membranes (PSM), very small unilamellar vesicles (VSUV) containing fluorescent lipids or model transmembrane proteins were generated by detergent depletion with cyclodextrin. Thus, very rapid reconstitution of membrane proteins into PSM was possible in a format compatible with microfluidics. Moreover, surfaces could be regenerated with detergent solution and reused multiple times. Lipid and protein diffusion in these membranes was investigated by fluorescence recovery after photobleaching, single molecule tracking, and fluorescence correlation spectroscopy. Full mobility of lipids and a high degree of protein mobility as well as homogeneous diffusion of both were observed. Quantitative ligand binding studies by solid phase detection techniques confirmed functional integrity of a transmembrane receptor reconstituted into these PSM. Colocomotion of individual ligand-receptor complexes was detected, demonstrating the applicability for single molecule fluorescence techniques.

  • 184.
    Rosenhahn, Axel
    et al.
    Univ Heidelberg, D-69120 Heidelberg, Germany.
    Ederth, Thomas
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Pettitt, Michala E.
    Univ Birmingham, Sch Biosci, Birmingham B15 2TT, W Midlands, England.
    Advanced nanostructures for the control of biofouling: The FP6 EU Integrated Project AMBIO2008Ingår i: BIOINTERPHASES, ISSN 1559-4106, Vol. 3, nr 1, s. IR1-IR5Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The colonization of man made structures by marine or freshwater organisms or "biofouling" is a problem for maritime and aquaculture industries. Increasing restrictions on the use of toxic coatings that prevent biofouling, create a gap in the market that requires new approaches to produce novel nonbiocidal alternatives. This review details the systematic strategy adopted by an FP6 EU Integrated Project "AMBIO" to develop fundamental understanding of key surface properties that influence settlement and adhesion of fouling organisms. By this approach the project contributes to the understanding of fundamental phenomena involved in biofouling, and to the development of environmentally benign solutions by coating manufacturers within the consortium. (c) 2008 American Vacuum Society.

  • 185. Rotomskis, R
    et al.
    Augulis, R
    Snitka, V
    Valiokas, Ramunas
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Liedberg, Bo
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Hierarchical structure of TPPS4 J-aggregates on substrate revealed by atomic force microscopy2004Ingår i: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 108, nr 9, s. 2833-2838Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The spatial structure of the J-aggregates of meso-tetra(4-sulfonatophenyl)porphine (TPPS4) formed in acidic aqueous solutions and coated on silicon substrates was analyzed by means of atomic force microscopy (AFM). The AFM experiments indicate the presence of the stripelike J-aggregate structures on the surface. The size of the individual stripes ranged from 4.5 x 40 x 200 to 4.5 x 40 x 1000 nm(3) (height x width x length). The length of the stripelike structures varied, whereas stripe width and thickness remained unchanged. The stripes stacked into larger domains, "fibers", containing typically 2-20 stripes aligned parallel with a longitudinal shift with respect to each other. The size of individual stripes remained the same when interacting side-by-side in fibers. At lower magnification it is clearly seen that fibers form a network-like structure. The J-aggregates assemble into large (up to several millimeters) bushlike structures. It takes several weeks to form such structures in acidic aqueous solutions. On the basis of our experimental findings, it is also suggested that the stripes consist of rings that form nanotube-like TPPS4 J-aggregates, which are flattened as a result of attractive interactions with the substrate.

  • 186.
    Sadreev, A.F.
    et al.
    Kirensky Institute of Physics, 660036, Krasnoyarsk, Russian Federation, Dept. of Phys. and Msrmt. Technology, Linkoping University, S-581 83 Linkoping, Sweden.
    Sukhunin, Y.V.
    Kirensky Institute of Physics, 660036, Krasnoyarsk, Russian Federation.
    Petoral, Rodrigo .M.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Uvdal, Kajsa
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Ground state and phase transitions in a system of arg-cysteamines self-assembled on a Au(111) crystal surface2004Ingår i: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 120, nr 2, s. 954-960Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 187.
    Sadreev, Almas
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Sukhinin, Y.V.
    Uvdal, Kajsa
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Pohl, A.
    Thermal reduction of activation energy of tricyclohexylphosphine on a rhodium crystal surface2001Ingår i: Journal of Chemical Physics, ISSN 0021-9606, E-ISSN 1089-7690, Vol. 115, nr 20, s. 9513-9518Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 188.
    Salomonsson, Anette
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik. Linköpings universitet, Tekniska högskolan.
    Petoral Jr., Rodrigo M.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Uvdal, Kajsa
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Aulin, Christian
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    Käll, Per-Olov
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Fysikalisk Kemi. Linköpings universitet, Tekniska högskolan.
    Ojamäe, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Fysikalisk Kemi. Linköpings universitet, Tekniska högskolan.
    Strand, Michael
    School of Technology and Design/Chemistry, Växjö University, Växjö, Sweden.
    Sanati, Mehri
    School of Technology and Design/Chemistry, Växjö University, Växjö, Sweden.
    Lloyd Spetz, Anita
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik. Linköpings universitet, Tekniska högskolan.
    Nanocrystalline Ruthenium oxide and Ruthenium in sensing applications -an experimental and theoretical study2006Ingår i: Journal of Nanoparticle Research, ISSN 1388-0764, Vol. 8, nr 6, s. 899-910Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 189.
    Schaferling, M.
    et al.
    Schäferling, M., Thermo Hybaid GmbH, Sedanstraße 10, 89077 Ulm, Germany, Institute of Analytical Chemistry, University of Regensburg, 93040 Regensburg, Germany.
    Riepl, M.
    Pavlickova, P.
    Thermo Hybaid GmbH, Sedanstraße 10, 89077 Ulm, Germany.
    Paul, H.
    Thermo Hybaid GmbH, Sedanstraße 10, 89077 Ulm, Germany.
    Kambhampati, D.
    Thermo Hybaid GmbH, Sedanstraße 10, 89077 Ulm, Germany.
    Liedberg, Bo
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Functionalized Self-Assembled Monolayers on Gold as Binding Matrices for the Screening of Antibody-Antigen Interactions2003Ingår i: Mikrochimica Acta, ISSN 0026-3672, E-ISSN 1436-5073, Vol. 142, nr 4, s. 193-203Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Two different types of w-substituted alkanethiol/disulfide compounds have been used to prepare monolayer architectures on gold serving as platforms for the immobilization of receptor probe molecules - antibodies. These are: (i) carboxylic acid alkanethiols post-reacted with amino biotin to generate streptavidin surfaces, and (ii) N-hydroxysuccinimide-terminated disulfide surfaces. The properties of the monolayers, with and without attached receptor probe molecules, were analysed using infrared spectroscopy, ellipsometry, fluorescence scanning and atomic force microscopy. Several experimental parameters, such as condensation reagents, additives, probe and target concentrations and immobilization time, were systematically varied to determine the dynamic range and to optimize the sensitivity and signal-to-noise ratio of the biochip platforms. Fluorescence screening using Cy5-labelled antigens finally demonstrated that both surfaces could be successfully employed to immobilize the antibodies. The pros and cons of the two approaches are also discussed.

  • 190.
    Selegård, Linnéa
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär ytfysik och nanovetenskap. Linköpings universitet, Tekniska fakulteten.
    Khranovskyy, Volodymyr
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Söderlind, Fredrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär ytfysik och nanovetenskap. Linköpings universitet, Tekniska fakulteten.
    Vahlberg, Cecilia
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Ahrén, Maria
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär ytfysik och nanovetenskap. Linköpings universitet, Tekniska fakulteten.
    Käll, Per-Olov
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Fysikalisk Kemi. Linköpings universitet, Tekniska högskolan.
    Yakimova, Rositsa
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Uvdal, Kajsa
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär ytfysik och nanovetenskap. Linköpings universitet, Tekniska fakulteten.
    Biotinylation of ZnO Nanoparticles and Thin Films: A Two-Step Surface Functionalization Study2010Ingår i: ACS APPLIED MATERIALS and INTERFACES, ISSN 1944-8244, Vol. 2, nr 7, s. 2128-2135Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 191.
    Sen, Pinar
    et al.
    Gebze Institute of Technology, Department of Chemistry, Gebze, Kocaeli, Turkey and Université de Lyon, Laboratoire de Chimie de l’ENS Lyon, Lyon, France.
    Hirel, Catherine
    Gebze Institute of Technology, Department of Chemistry, Gebze, Kocaeli, Turkey.
    Andraud, Chantal
    Université de Lyon, Laboratoire de Chimie de l’ENS Lyon, Lyon, France.
    Aronica, Christophe
    Université de Lyon, Laboratoire de Chimie de l’ENS Lyon, Lyon, France.
    Bretonniere, Yann
    Université de Lyon, Laboratoire de Chimie de l’ENS Lyon, Lyon, France.
    Mohammed, Abdelsalam
    Theoretical Chemistry, Royal Institute of Technology, Stockholm, Sweden .
    Ågren, Hans
    Theoretical Chemistry, Royal Institute of Technology, Stockholm, Sweden.
    Minaev, Boris
    B. Khmelnitski national University, Cherkassy, Ukraine .
    Minaeva, Valentina
    B. Khmelnitski national University, Cherkassy, Ukraine .
    Baryshnikov, Gleb
    B. Khmelnitski national University, Cherkassy, Ukraine .
    Lee, Hung-Hsun
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Duboisset, Julien
    Department of Physics, Norwegian University of Science and Technology, NO-7491, Trondheim, Norway.
    Lindgren, Mikael
    Université de Lyon, Laboratoire de Chimie de l’ENS Lyon, Lyon, France and Department of Physics, Norwegian University of Science and Technology, Trondheim, Norway.
    Fluorescence and FTIR Spectra Analysis of Trans-A(2)B(2)-Substituted Di- and Tetra-Phenyl Porphyrins2010Ingår i: Materials, ISSN 1996-1944, E-ISSN 1996-1944, Vol. 3, nr 8, s. 4446-4475Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A series of asymmetrically substituted free-base di- and tetra-phenylporphyrins and the associated Zn-phenylporphyrins were synthesized and studied by X-ray diffraction, NMR, infrared, electronic absorption spectra, as well as fluorescence emission spectroscopy, along with theoretical simulations of the electronic and vibration structures. The synthesis selectively afforded trans-A(2)B(2) porphyrins, without scrambling observed, where the AA and BB were taken as donor-and acceptor-substituted phenyl groups. The combined results point to similar properties to symmetrically substituted porphyrins reported in the literature. The differences in FTIR and fluorescence were analyzed by means of detailed density functional theory (DFT) calculations. The X-ray diffraction analysis for single crystals of zinc-containing porphyrins revealed small deviations from planarity for the porphyrin core in perfect agreement with the DFT optimized structures. All calculated vibrational modes (2162 modes for all six compounds studied) were found and fully characterized and assigned to the observed FTIR spectra. The most intense IR bands are discussed in connection with the generic similarity and differences of calculated normal modes. Absorption spectra of all compounds in the UV and visible regions show the typical ethio type feature of meso-tetraarylporphyrins with a very intense Soret band and weak Q bands of decreasing intensity. In diphenyl derivatives, the presence of only two phenyl rings causes a pronounced hypsochromic shift of all bands in the absorption spectra. Time-dependent DFT calculations revealed some peculiarities in the electronic excited states structure and connected them with vibronic bands in the absorption and fluorescence spectra from associated vibrational sublevels.

    Ladda ner fulltext (pdf)
    fulltext
  • 192.
    Shi, Shengwei
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska högskolan.
    Sadhu, Veera
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Moubah, Reda
    Uppsala University, Sweden .
    Schmerber, Guy
    University of Strasbourg, France .
    Bao, Qinye
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Tekniska högskolan.
    Ravi P Silva, S
    University of Surrey, England .
    Solution-processable graphene oxide as an efficient hole injection layer for high luminance organic light-emitting diodes2013Ingår i: JOURNAL OF MATERIALS CHEMISTRY C, ISSN 2050-7526, Vol. 1, nr 9, s. 1708-1712Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The application of solution-processable graphene oxide (GO) as a hole injection layer in organic light-emitting diodes (OLEDs) is demonstrated. High luminance of over 53 000 cd m(-2) is obtained at only 10 V. The results will unlock a route to apply GO in flexible OLEDs and other electrode applications.

  • 193.
    Stuppy, S.M.
    et al.
    Applied Physical Chemistry, Ruprecht-Karls-University Heidelberg, Heidelberg, Germany; Institute for Functional Interfaces, IFG, Karlsruhe Institute of Technology, Karlsruhe, Germany.
    Arpa Sancet, M. P.
    Applied Physical Chemistry, Ruprecht-Karls-University Heidelberg, Heidelberg, Germany; Institute for Functional Interfaces, IFG, Karlsruhe Institute of Technology, Karlsruhe, Germany.
    Heydt, M.
    Ocean Engineering and Oceanography, Florida Institute of Technology, Melbourne Florida, USA.
    Schilp, S.
    Ocean Engineering and Oceanography, Florida Institute of Technology, Melbourne Florida, USA.
    Zargiel, K.
    Ocean Engineering and Oceanography, Florida Institute of Technology, Melbourne Florida, USA.
    Ederth, Thomas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Liedberg, Bo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Swain, G. W.
    Ocean Engineering and Oceanography, Florida Institute of Technology, Melbourne Florida, USA.
    Callow, J. A.
    School of Bioscience, University of Birmingham, Birmingham, UK.
    Callow, M. E.
    School of Bioscience, University of Birmingham, Birmingham, UK.
    Rosenhahn, A.
    Institute for Functional Interfaces, IFG, Karlsruhe Institute of Technology, Karlsruhe, Germany.
    Grunze, M.
    Applied Physical Chemistry, Ruprecht-Karls-University Heidelberg, Heidelberg, Germany; Institute for Toxicology and Genetics, ITG, Karlsruhe Institute of Technology, Karlsruhe, Germany.
    From lab to field - chemistry depending surface colonization and 3D tracking2011Konferensbidrag (Övrigt vetenskapligt)
    Ladda ner fulltext (pdf)
    fulltext
  • 194.
    Suriyanarayanan, Subrarnanian
    et al.
    Linnaeus University, Sweden .
    Lee, Hung-Hsun
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Liedberg, Bo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Aastrup, Teodor
    Attana AB, Sweden .
    Nicholls, Ian A
    Linnaeus University, Sweden .
    Protein-resistant hyperbranched polyethyleneimine brush surfaces2013Ingår i: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 396, s. 307-315Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A novel hyperbranched polyethyleneimine (PEI) modified gold surface has been designed, fabricated, and investigated with respect to its ability to resist non-specific adsorption of proteins. The facile synthesis strategy, based on self-assembly, involves immobilization of polyethyleneimine to gold surfaces modified with 11-mercaptoundecanoic acid (MuDA) monolayers using traditional carbodiimide chemistry. The hyperbranched polymer brushes were characterized by X-ray photoelectron spectroscopy (XPS). Reflection absorption infrared spectroscopy (RAIRS) and ellipsometry measurements showed the thickness of the PEI brushes increases with adsorption solution ionic strength. Polymer brush surface concentrations can be improved from 2560 to 3880 chains/mu m(2) by changing the ionic strength of the adsorption solution (PBS) by varying NaCl concentration from 0 to 650 mM. Protein adsorption (pH 7.4) was evaluated under flow injection analysis (FIA) conditions using a quartz crystal microbalance (QCM). The PEI brushes suppress protein adsorption, for example, cytochrome C, bovine serum albumin (BSA), and ribonuclease A, to less than 0.08 mu g/cm(2) and the protein resistance increases with increasing ionic strength of the carrier solution, performance comparable to that achieved with comparable PEG-coated surfaces. The PEI brushes were exceptionally stable, with adsorption characteristics maintained after 6 months storage in aqueous conditions (pH 7.4, 25 degrees C, PBS). The potential of hyperbranched PEI structures as protein-resistant surfaces is discussed.

  • 195.
    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 interfaces2001Ingår i: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 66, nr 13, s. 4494-4503Artikel i tidskrift (Refereegranskat)
    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.

  • 196.
    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 interactions2002Ingår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 18, nr 7, s. 2848-2858Artikel i tidskrift (Refereegranskat)
    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.

  • 197.
    Söderlind, Fredrik
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Oorganisk Kemi. Linköpings universitet, Tekniska högskolan.
    Pedersen, Henrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Petoral, Rodrigo M.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Käll, Per-Olov
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Fysikalisk Kemi. Linköpings universitet, Tekniska högskolan.
    Uvdal, Kajsa
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Synthesis and characterisation of Gd2O3 nanocrystals functionalised by organic acids2005Ingår i: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 288, nr 1, s. 140-148Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 198.
    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 polymerization2014Ingår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 15, nr 7, s. 2359-2368Artikel i tidskrift (Refereegranskat)
    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.

    Ladda ner fulltext (pdf)
    fulltext
  • 199.
    Tengvall, Pentti
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik.
    Kindgren, Alf
    Järrendahl, Kenneth
    Uvdal, Kajsa
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    CDIO-based courses in engineering biology at LiTH2005Ingår i: CDIO International Conference and Collaborators meeting,2005, 2005Konferensbidrag (Övrigt vetenskapligt)
  • 200.
    Ulrich, Christian
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik.
    Andersson, Olof
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Leif, Nyholm
    Björefors, Fredrik
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Surface Gradients on Bipolar Electrodes2008Ingår i: ESEAC2008 European Society for ElectroAnalytical Chemistry,2008, 2008Konferensbidrag (Övrigt vetenskapligt)
12345 151 - 200 av 250
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • oxford
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf