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  • 1.
    Bittoun, Eyal
    et al.
    Technion Israel Institute Technology.
    Marmur, Abraham
    Technion Israel Institute Technology.
    Östblom, Mattias
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics . Linköping University, The Institute of Technology.
    Ederth, Thomas
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics . Linköping University, The Institute of Technology.
    Liedberg, Bo
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics . Linköping University, The Institute of Technology.
    Filled Nanoporous Surfaces: Controlled Formation and Wettability2009In: LANGMUIR, ISSN 0743-7463, Vol. 25, no 20, p. 12374-12379Article in journal (Refereed)
    Abstract [en]

    The controlled filling of hydrophobic nanoporous surfaces with hydrophilic molecules and their wetting properties are described and demonstrated by using thiocholesterol (TC) self-assembled monolayers (SAMs) on gold and mercaptoundecanoic acid (MUA) as the filling agent. A novel procedure was developed for filling the nanopores in the TC SAMs by immersing them into a "cocktail" solution of TC and MUA, with TC in huge excess. This procedure results in an increasing coverage of MUA with increasing immersion time up to an area fraction of similar to 23%, while the amount of TC remains almost constant. Our findings strongly support earlier observations where linear omega-substituted alkanethiols selectively fill defects (nanopores) in the TC SAM (Yang et al. Langmuir 1997, 12, 1704-1707). They also support the formation of a homogeneously mixed SAM, given by the distribution of TC on the gold surface, rather than of a phase-segregated overlayer structure with domains of varying size, shape, and composition. The wetting properties of the Filled SAMs were investigated by measuring the most stable contact angle as well as contact angle hysteresis. It is shown that the most stable contact angle is very well described by the Cassie equation, since the drops arc much larger than the scale of chemical heterogeneity of the SAM surfaces. In addition, it is demonstrated that contact angle hysteresis is sensitive to the chemical heterogeneity of the surface, even at the nanometric scale.

  • 2. Demers, LM
    et al.
    Östblom, Mattias
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Zhang, Hanmin
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Jang, NH
    Liedberg, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Mirkin, CA
    Thermal desorption behavior and binding properties of DNA bases and nucleosides on gold2002In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 124, no 38, p. 11248-11249Article in journal (Refereed)
  • 3.
    Ederth, Thomas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Nygren, Patrik
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Ekblad, Tobias
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Östblom, Mattias
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Liedberg, Bo
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Pettitt, M.E.
    The University of Birmingham, School of Biosciences, Birmingham, UK.
    Callow, M.E.
    The University of Birmingham, School of Biosciences, Birmingham, UK.
    Callow, J.A.
    The University of Birmingham, School of Biosciences, Birmingham, UK.
    Interactions of algal spores and diatoms with mixed synthetic peptide SAMs2007Conference paper (Other academic)
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  • 4. Hellgren, N.
    et al.
    Johansson, Mats P
    Hjorvarsson, B.
    Hjörvarsson, B., Materials Physics, Royal Institute of Technology, Teknikringen 14, S-100 44 Stockholm, Sweden.
    Broitman, E.
    Östblom, Mattias
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Liedberg, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Hultman, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Sundgren, J.-E.
    Growth, structure, and mechanical properties of CNxHy films deposited by dc magnetron sputtering in N2/Ar/H2 discharges2000In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 18, no 5, p. 2349-2358Article in journal (Refereed)
    Abstract [en]

    Reactive direct current magnetron sputtering was used to deposit the hydrogenated carbon nitride films in mixed nitrogen (N2)/argon (Ar)/ hydrogen (H2) discharges. Growth and structure evolution of films was found to be affected by chemical sputtering effects. The hydrogen were found to be bonded to nitrogen and hydrogen incorporation decreases the elasticity and hardness.

  • 5.
    Li, Wei
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences.
    Östblom, Mattias
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Xu, Lihua
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Experimental Pathology .
    Hellsten, A.
    Leanderson, Per
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Occupational and Environmental Medicine . Östergötlands Läns Landsting, Centre for Medicine, Pain and Rehabilitation Centre.
    Liedberg, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Brunk, Ulf
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Health Sciences, Pharmacology .
    Eaton, J.W.
    James Graham Brown Cancer Center, University of Louisville, Louisville, KY, United States.
    Yuan, Ximing
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine.
    Cytocidal effects of atheromatous plaque components: The death zone revisited2006In: The FASEB Journal, ISSN 0892-6638, E-ISSN 1530-6860, Vol. 20, no 13, p. 2281-2290Article in journal (Refereed)
    Abstract [en]

    Objective: Earlier we suggested that atheroma lesions constitute a "death zone" containing toxic materials that may cause dysfunction and demise of invading macrophages to prevent the removal of plaque materials. Here we have assessed the cytotoxic effects of nonfractionated gruel and insoluble (ceroid-like) material derived from advanced human atheroma. Methods and Results: The insoluble material within advanced atherosclerotic plaque was isolated following protease K digestion and extensive extraction with aqueous and organic solvents. FTIR, Raman, and atomic absorption spectroscopy suggested that, despite its fluorescent nature, this material closely resembled hydroxyapatite and dentin, but also contained a significant amount of iron and calcium. When added to J774 cells and human macrophages in culture, this insoluble substance was phagocytosed, and progressive cell death followed. However, an even more cytotoxic activity was found in the atheromatous "gruel" that contains abundant carbonyls/aldehydes. Cell death caused by both crude gruel and ceroid could be blocked by preincubating cells with the lipophilic iron chelator salicylaldehyde isonicotinoyl hydrazone, apoferritin, BAPTA/AM, or sodium borohydride, indicating that cellular iron, calcium, and reactive aldehyde(s) are responsible for the observed cytotoxicity. Conclusions: Toxic materials within atheromatous lesions include both ceroid and even more cytotoxic lipidaceous materials. The cytotoxic effects of these plaque components may help explain the persistence of atherosclerotic lesions. © FASEB.

  • 6.
    Li, Wei
    et al.
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Pathology.
    Östblom, Mattias
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Xu, Lihua
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Pathology.
    Hellsten, Anna
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery.
    Leanderson, Per
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Occupational and Environmental Medicine. Östergötlands Läns Landsting, Pain and Occupational Centre, Occupational and Environmental Medicine Centre.
    Liedberg, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Brunk, Ulf
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Pharmacology.
    Eaton, John Wallace
    USA .
    Yuan, Xi Ming
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Neuroscience and Locomotion, Pathology.
    Cytocidal effects of atheromatous plaque components: the death zone revisited.2006In: The FASEB Journal, ISSN 0892-6638, E-ISSN 1530-6860, Vol. 20, p. 2281-2290Article in journal (Refereed)
    Abstract [en]

       

  • 7.
    Music, Denis
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Schneider, Jochen
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Kugler, Veronika Mozhdeh
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    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
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Hultman, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Helmersson, Ulf
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Plasma and Coating Physics .
    Synthesis and mechanical properties of boron suboxide thin films2002In: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 20, no 2, p. 335-337Article in journal (Refereed)
    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.

  • 8. Riepl, M.
    et al.
    Östblom, Mattias
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Lundström, Ingemar
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    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
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Molecular gradients: An efficient approach for optimizing the surface properties of biomaterials and biochips2005In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 21, no 3, p. 1042-1050Article in journal (Refereed)
    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.

  • 9.
    Valiokas, Ramunas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Svedhem, Sofia
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology. University of Uppsala, Department of Physics, Uppsala, Sweden.
    Östblom, Mattias
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Gelius, U
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology. University of Uppsala, Department of Physsics, Uppsala, Sweden.
    Svensson, SCT
    Liedberg, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics.
    Tunable phases of oligo (ethylene glycol) in self-assembled monolayers and their use as support for lipid bilayers2000In: Abstracts of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 219, p. 397-397Article in journal (Other academic)
  • 10.
    Valiokas, Ramunas
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Svedhem, Sofia
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    Östblom, Mattias
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics.
    Svensson, Stefan
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry.
    Liedberg, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics.
    Influence of specific intermolecular interactions on the self-assembly and phase behavior of oligo(ethylene glycol)-terminated alkanethiolates on gold2001In: Journal of Physical Chemistry B, ISSN 1089-5647, Vol. 105, no 23, p. 5459-5469Article in journal (Refereed)
    Abstract [en]

    A comparative study of the self-assembly and phase behavior of seven different oligo(ethylene glycol) (OEG)-terminated alkanethiols on polycrystalline gold surfaces is presented. The general structure of the compounds is HS(CH2)m-X-EGn, where m = 11, 15, n = 2, 4, 6, and the linkages X are amide (-CONH-), ester (-COO-), or ether (-O-) groups. The amide and ester groups give rise to the intermolecular hydrogen bonding and dipole-dipole interactions, respectively, whereas the ether lacks specific interactions. The results from contact angle goniometry, null ellipsometry, and infrared reflection-absorption spectroscopy (IRAS) indicate that the intermolecular interactions can be partly used to control the conformation and order of the OEG portion of the self-assembled monolayers (SAMs). It is shown that the lateral hydrogen bonding stabilizes the all-trans conformation of the EG4 tails in the SAMs. Further on, the mechanism behind the thermal phase behavior of the OEG SAMs is investigated using temperature-programmed IRAS in ultrahigh vacuum. In the present study we show that the earlier reported helix-to-all-trans conformational transition at 60°C in the SAM of HS(CH2)15CONH-EG6 (Valiokas, R., Östblom, M., Svedhem, S., Svensson, S. C. T., Liedberg, B. J. Phys. Chem. 2000, 104, 7565-7569.) is a result of the particular molecular design of the SAMs through the specifically built-in lateral hydrogen bonds. A shortening of the alkyl chain to 11 methylenes has no effect on the amide-EG6 phase behavior. Contrary, the ester- and ether- containing SAMs undergo a melting type of transitions at 52 and 68°C, respectively, similar to that observed for poly(ethylene glycol).

  • 11.
    Valiokas, Ramunas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Östblom, Mattias
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics.
    Björefors, Fredrik
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics.
    Liedberg, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics.
    Shi, Jing
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Konradsson, Peter
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry.
    Structural and kinetic properties of laterally stabilized, oligo(ethylene glycol)-containing alkylthiolates on gold: A modular approach2006In: Biointerphases, ISSN 1934-8630, E-ISSN 1559-4106, Vol. 1, no 1, p. 22-34Article in journal (Refereed)
    Abstract [en]

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

  • 12.
    Valiokas, Ramunas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Östblom, Mattias
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics. Linköping University, The Institute of Technology.
    Svedhem, Sofia
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    Svensson, Stefan C. T.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Liedberg, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics.
    Temperature-driven phase transitions in oligo(ethylene glycol)-terminated self-assembled monolayers2000In: The Journal of Physical Chemistry B, ISSN 1520-6106, Vol. 104, no 32, p. 7565-7569Article in journal (Other academic)
    Abstract [en]

    This letter explores the phase behavior of oligo(ethylene glycol) self-assembled monolayers using temperature-programmed infrared reflection absorption spectroscopy. The monolayers are formed by self-assembly of hexa(ethylene glycol) (EG(6)) and tetra(ethylene glycol) (EG(4))-terminated and amide group containing alkanethiols on polycrystalline gold. The ethylene glycol portions of the two monolayers are known to exist in two different conformations at room temperature: EG(6) in helical and EG(4) in all-trans (zigzag). The helical phase of the EG(6) gradually diminishes upon increasing the temperature and a pronounced conformational transition occurs around 60 degrees C, leading to a rapidly increasing population of all-trans conformers along the EG(6) chain. The EG(4) SAM exhibits a much simpler phase behavior. The oligomer conformation is marginally affected upon increasing the temperature to 75 degrees C, displaying the dominating all-trans phase, which possibly coexists with a small fraction of gauche-rich (disordered) regions. The reported conformational changes are reversible upon returning to 20 degrees C after stepwise heating to 70 degrees C.

  • 13.
    Valiokas, Ramunas
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Östblom, Mattias
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics.
    Svedhem, Sofia
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    Svensson, Stefan C.T.
    Linköping University, Department of Computer and Information Science. Linköping University, The Institute of Technology.
    Liedberg, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics.
    Thermal stability of self-assembled monolayers: Influence of lateral hydrogen bonding2002In: Journal of Physical Chemistry B, ISSN 1089-5647, Vol. 106, no 40, p. 10401-10409Article in journal (Refereed)
    Abstract [en]

    Temperature-programmed desorption (TPD) of self-assembled monolayers (SAMs) on gold is investigated by using in parallel mass spectrometry (MS) and infrared reflection-absorption spectroscopy (IRAS). Monolayers formed by HS(CH2)n-OH (n = 18, 22) and HS(CH2)15-CONH-(CH2CH2O)-H (EG1) are compared to reveal the influence of specifically introduced hydrogen-bonding groups on their thermal stability. The overall desorption process of the above molecules is found to occur in two main steps, a disordering of the alkyl chains followed by a complex series of decomposition/desorption reactions. The final step of the process involves desorption of sulfur from different chemisorption states. The amide-group-containing SAM, which is stabilized by lateral hydrogen bonds, displays a substantial delay of the alkyl chain disordering by about 50 K, as compared to the linear chain alcohols HS(CH2)n-OH. Moreover, the decomposition of the alkyls and the onset of sulfur desorption occur at a temperature that is higher by approximately 25 K as compared to the HS(CH2)18-OH SAM. The desorption process is also studied for two oligo(ethylene glycol)-terminated SAMs, HS(CH2)15-X-(CH2CH2O)4-H (EG4-SAMs), where X is -CONH- and -COO- linking groups. In addition to the molecular chain disordering, the decomposition/desorption process of the EG4-SAMs occurs in two steps. The first is associated with the loss of the oligomer portion and the second with the desorption of the alkylthiolate part of the molecule. Our study points out that lateral hydrogen bonding, introduced via amide groups, is a convenient way to improve the thermal stability of alkanthiolate SAMs.

  • 14.
    Wang, Xiangjun
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    Östblom, Mattias
    Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics . Linköping University, The Institute of Technology.
    Johansson, Tomas
    Linköping University, Department of Physics, Chemistry and Biology.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics . Linköping University, The Institute of Technology.
    PEDOT surface energy pattern controls fluorescent polymer deposition by dewetting2004In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 449, no 1-2, p. 125-132Article in journal (Refereed)
    Abstract [en]

    An elastomeric stamp of poly(dimethylsiloxane) (PDMS) can modify the surface energy of some surfaces when brought into conformal contact with these for some time. The substrates under investigation are a conducting polymer poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT-PSS) and a polyelectrolyte poly(sodium 4-styrenesulfonate) (NaPSS). The changes in surface wetting are characterized by contact angle measurement. Changes are due to the PDMS stamp, which leaves low molecular weight residues on the surface, as shown by infrared reflection absorption spectroscopy. This process may also be operating when other inks are transferred in microcontact printing. Patterning of fluorescent polymer film with feature size of 10–100 μm range is done by confining polymer solutions on the modified surface, by means of spin- or dip-coating. The profile of the patterned film and factors that influence the profile are discussed. This technique is a convenient way to build polymer microstructures for application in organic and biomolecular electronics and photonics.

  • 15.
    Östblom, Mattias
    Linköping University, Department of Physics, Measurement Technology, Biology and Chemistry. Linköping University, The Institute of Technology.
    Temperature programmed studies of molecular assemblies on gold2004Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis investigates the properties of ultra-thin layers of organic molecules deposited at or adsorbed onto thin films of gold. The two main experimental techniques used in this thesis work are Temperature Programmed Desorption-Infrared Reflection Absorption Spectroscopy (TPD-IRAS), an excellent technique to probe the structure and orientation of molecular layers on metallic substrates, and Temperature Programmed Desorption-Mass Spectroscopy (TPD-MS), a very useful tool to study the energetics of molecular layers and adsorbates on solid surfaces. The two techniques are especially powerful when used simultaneously because they can be used to 1) follow molecular rearrangement phenomena occurring prior and during desorption; 2) find correlations between such rearrangement phenomena and the ultimate binding strength of the molecules/adsorbates to the surface.

    The TPD-IRAS and TPD-MS techniques have been used to study: I) the structure and desorption dynamics of DNA bases on gold; II) the phase behavior of oligo(ethylene glycol) (OEG)-terminated selfassembled monolayers (SAMs) on gold; and III) the nucleation, growth and structure of D2O-ice on SAMsat liquid nitrogen temperatures in ultra high vacuum.

    The first part investigates the orientation, structure and binding strength of DNA bases spontaneously adsorbed to gold. The four DNA bases interact very differently on and with the gold surface. Guanine and adenine interact strongly with the surface, and displays a series of complex structural transitions during the desorption event. Adenine form strong bonds with the gold surface, whereas cohesive interactions seem to dominate for guanine. Cytosine and thymine display a less complicated desorption behavior, and the corresponding desorption energies are lower/ much lower than those observed for adenine and guanine. These results are in qualitative agreement with recent studies of the activity of immobilized oligonucleotides on gold nanoparticles.

    The second part is a study of SAMs of thiolated molecules on gold exposing OEG-tails in different conformations, all trans and helical, toward the ambient. The temperature dependence is investigated using TPD-IRAS, and it is found that the helical OEGs undergo a reversible phase transition into the all trans oramorphous states at approximately 60 °C, depending on chemical groups used to attach the OEG tail tothe alkyl thiol portion.

    The third part focuses on ultra-thin ad-layers of D2O deposited onto OEG substrates at low temperature in UHV. Extensive simulations of RA spectra of the D2O-ice overlayers are performed using Maxwell Garnett effective medium theory to support the interpretation of the experimental data. These simulations reveal that the ice overlayers contain a significant and varying volume fraction of voids. Isothermal annealing ofthe ice overlayers shows that the kinetics of the amorphous to crystalline phase transition of ice, normally observed at about 140 K, is strongly dependent on the conformation of the OEG layer. The kinetics is fast on helical OEG SAMs most likely because of the existence of specific nucleation sites that governs the crystalline formation of ice.

    The binding strength and structure of D2O deposited to biomimetic phosphate SAMs with H+, Na+ and Ca2+ as counter-ions are also investigated. D2O is tightly bound to Ca2+- and Na+- phosphate SAMs, affecting several ad-layers of D2O. These results may have implication for the chemistry occurring at biomineral surfaces, and specifically for the role of water on the nucleation and growth of hydroxyapatite, the inorganic component in bone.

    List of papers
    1. Thermal desorption behavior and binding properties of DNA bases and nucleosides on gold
    Open this publication in new window or tab >>Thermal desorption behavior and binding properties of DNA bases and nucleosides on gold
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    2002 (English)In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 124, no 38, p. 11248-11249Article in journal (Refereed) Published
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-47851 (URN)10.1021/ja0265355 (DOI)
    Available from: 2009-10-11 Created: 2009-10-11 Last updated: 2021-09-24
    2. On the structure and desorption dynamics of DNA bases adsorbed on gold: A temperature-programmed study
    Open this publication in new window or tab >>On the structure and desorption dynamics of DNA bases adsorbed on gold: A temperature-programmed study
    2005 (English)In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 109, no 31, p. 15150-15160Article in journal (Refereed) Published
    Abstract [en]

    The structure and desorption dynamics of mono- and multilayer samples of adenine, cytosine, guanine, and thymine on polycrystalline gold thin films are studied using temperature-programmed desorption-infrared reflection absorption spectroscopy (TPD-IRAS) and temperature-programmed desorption-mass spectroscopy (TPD-MS). It is shown that the pyrimidines, adenine and guanine, adsorb to gold in a complex manner and that both adhesive (adenine) and cohesive (guanine) interactions contribute the apparent binding energies to the substrate surface. Adenine displays at least two adsorption sites, including a high-energy site (210°C, ~136 kj/mol), wherein the molecule coordinates to the gold substrate via the NH2 group in an sp3-like, strongly perturbed, nonplanar configuration. The purines, cytosine and thymine, display a less complicated adsorption/desorption behavior. The desorption energy for cytosine (160°C, ~122 kJ/mol) is similar to those obtained for adenine and guanine, but desorption occurs from a single site of dispersed, nonaggregated cytosine. Thymine desorbs also from a single site but at a significantly lower energy (100°C, ~104 kJ/mol). Infrared data reveal that the monolayer architectures discussed herein are structurally very different from those observed for the bases in the bulk crystalline state. It is also evident that both pyrimidines and purines adsorb on gold with the plane of the molecule in a nonparallel orientation with respect to the substrate surface. The results of this work are discussed in the context of improving the understanding of the design of capturing oligonucleotides or DNA strands for bioanalytical applications, in particular, for gold nanoparticle-based assays. © 2005 American Chemical Society.

    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-50440 (URN)10.1021/jp051617b (DOI)
    Available from: 2009-10-11 Created: 2009-10-11 Last updated: 2021-09-24
    3. Temperature-driven phase transitions in oligo(ethylene glycol)-terminated self-assembled monolayers
    Open this publication in new window or tab >>Temperature-driven phase transitions in oligo(ethylene glycol)-terminated self-assembled monolayers
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    2000 (English)In: The Journal of Physical Chemistry B, ISSN 1520-6106, Vol. 104, no 32, p. 7565-7569Article in journal, Editorial material (Other academic) Published
    Abstract [en]

    This letter explores the phase behavior of oligo(ethylene glycol) self-assembled monolayers using temperature-programmed infrared reflection absorption spectroscopy. The monolayers are formed by self-assembly of hexa(ethylene glycol) (EG(6)) and tetra(ethylene glycol) (EG(4))-terminated and amide group containing alkanethiols on polycrystalline gold. The ethylene glycol portions of the two monolayers are known to exist in two different conformations at room temperature: EG(6) in helical and EG(4) in all-trans (zigzag). The helical phase of the EG(6) gradually diminishes upon increasing the temperature and a pronounced conformational transition occurs around 60 degrees C, leading to a rapidly increasing population of all-trans conformers along the EG(6) chain. The EG(4) SAM exhibits a much simpler phase behavior. The oligomer conformation is marginally affected upon increasing the temperature to 75 degrees C, displaying the dominating all-trans phase, which possibly coexists with a small fraction of gauche-rich (disordered) regions. The reported conformational changes are reversible upon returning to 20 degrees C after stepwise heating to 70 degrees C.

    Place, publisher, year, edition, pages
    American Chemical Society (ACS), 2000
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-49622 (URN)10.1021/jp001536+ (DOI)
    Available from: 2009-10-11 Created: 2009-10-11 Last updated: 2022-06-17Bibliographically approved
    4. Thermal stability of self-assembled monolayers: Influence of lateral hydrogen bonding
    Open this publication in new window or tab >>Thermal stability of self-assembled monolayers: Influence of lateral hydrogen bonding
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    2002 (English)In: Journal of Physical Chemistry B, ISSN 1089-5647, Vol. 106, no 40, p. 10401-10409Article in journal (Refereed) Published
    Abstract [en]

    Temperature-programmed desorption (TPD) of self-assembled monolayers (SAMs) on gold is investigated by using in parallel mass spectrometry (MS) and infrared reflection-absorption spectroscopy (IRAS). Monolayers formed by HS(CH2)n-OH (n = 18, 22) and HS(CH2)15-CONH-(CH2CH2O)-H (EG1) are compared to reveal the influence of specifically introduced hydrogen-bonding groups on their thermal stability. The overall desorption process of the above molecules is found to occur in two main steps, a disordering of the alkyl chains followed by a complex series of decomposition/desorption reactions. The final step of the process involves desorption of sulfur from different chemisorption states. The amide-group-containing SAM, which is stabilized by lateral hydrogen bonds, displays a substantial delay of the alkyl chain disordering by about 50 K, as compared to the linear chain alcohols HS(CH2)n-OH. Moreover, the decomposition of the alkyls and the onset of sulfur desorption occur at a temperature that is higher by approximately 25 K as compared to the HS(CH2)18-OH SAM. The desorption process is also studied for two oligo(ethylene glycol)-terminated SAMs, HS(CH2)15-X-(CH2CH2O)4-H (EG4-SAMs), where X is -CONH- and -COO- linking groups. In addition to the molecular chain disordering, the decomposition/desorption process of the EG4-SAMs occurs in two steps. The first is associated with the loss of the oligomer portion and the second with the desorption of the alkylthiolate part of the molecule. Our study points out that lateral hydrogen bonding, introduced via amide groups, is a convenient way to improve the thermal stability of alkanthiolate SAMs.

    Place, publisher, year, edition, pages
    American Chemical Society (ACS), 2002
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-46802 (URN)10.1021/jp0200526 (DOI)
    Available from: 2009-10-11 Created: 2009-10-11 Last updated: 2022-06-17Bibliographically approved
    5. Ice nucleation and phase behavior on oligo(ethylene glycol) and hydroxyl self-assembled monolayers: Simulations and experiments
    Open this publication in new window or tab >>Ice nucleation and phase behavior on oligo(ethylene glycol) and hydroxyl self-assembled monolayers: Simulations and experiments
    Show others...
    2006 (English)In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 110, no 4, p. 1830-1836Article in journal (Refereed) Published
    Abstract [en]

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

    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-50302 (URN)10.1021/jp056007q (DOI)
    Available from: 2009-10-11 Created: 2009-10-11 Last updated: 2021-09-24
    6. Structure and desorption energetics of ultrathin D2O ice overlay ers on serine- And serinephosphate-terminated self-assembled monolayers
    Open this publication in new window or tab >>Structure and desorption energetics of ultrathin D2O ice overlay ers on serine- And serinephosphate-terminated self-assembled monolayers
    2006 (English)In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 110, no 4, p. 1695-1700Article in journal (Refereed) Published
    Abstract [en]

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

    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-50301 (URN)10.1021/jp055169j (DOI)
    Available from: 2009-10-11 Created: 2009-10-11 Last updated: 2021-09-24
  • 16.
    Östblom, Mattias
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Ekeroth, Johan
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Konradsson, Peter
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry .
    Liedberg, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Structure and desorption energetics of ultrathin D2O ice overlay ers on serine- And serinephosphate-terminated self-assembled monolayers2006In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 110, no 4, p. 1695-1700Article in journal (Refereed)
    Abstract [en]

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

  • 17.
    Östblom, Mattias
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Liedberg, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Demers, L.M.
    Department of Chemistry, Center for Nanofabrication and Molecular Self-Assembly, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208.
    Mirkin, C.A.
    Department of Chemistry, Center for Nanofabrication and Molecular Self-Assembly, Northwestern University, 2145 Sheridan Road, Evanston, IL 60208.
    On the structure and desorption dynamics of DNA bases adsorbed on gold: A temperature-programmed study2005In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 109, no 31, p. 15150-15160Article in journal (Refereed)
    Abstract [en]

    The structure and desorption dynamics of mono- and multilayer samples of adenine, cytosine, guanine, and thymine on polycrystalline gold thin films are studied using temperature-programmed desorption-infrared reflection absorption spectroscopy (TPD-IRAS) and temperature-programmed desorption-mass spectroscopy (TPD-MS). It is shown that the pyrimidines, adenine and guanine, adsorb to gold in a complex manner and that both adhesive (adenine) and cohesive (guanine) interactions contribute the apparent binding energies to the substrate surface. Adenine displays at least two adsorption sites, including a high-energy site (210°C, ~136 kj/mol), wherein the molecule coordinates to the gold substrate via the NH2 group in an sp3-like, strongly perturbed, nonplanar configuration. The purines, cytosine and thymine, display a less complicated adsorption/desorption behavior. The desorption energy for cytosine (160°C, ~122 kJ/mol) is similar to those obtained for adenine and guanine, but desorption occurs from a single site of dispersed, nonaggregated cytosine. Thymine desorbs also from a single site but at a significantly lower energy (100°C, ~104 kJ/mol). Infrared data reveal that the monolayer architectures discussed herein are structurally very different from those observed for the bases in the bulk crystalline state. It is also evident that both pyrimidines and purines adsorb on gold with the plane of the molecule in a nonparallel orientation with respect to the substrate surface. The results of this work are discussed in the context of improving the understanding of the design of capturing oligonucleotides or DNA strands for bioanalytical applications, in particular, for gold nanoparticle-based assays. © 2005 American Chemical Society.

  • 18.
    Östblom, Mattias
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Valiokas, Ramunas
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Konradsson, Peter
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry .
    Svensson, Stefan
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry .
    Liedberg, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Garrett, M.
    Department of Chemistry and Materials Science, Pennsylvania State University, University Park, PA 16802.
    Allara, D.L.
    Department of Chemistry and Materials Science, Pennsylvania State University, University Park, PA 16802.
    Ice nucleation and phase behavior on oligo(ethylene glycol) and hydroxyl self-assembled monolayers: Simulations and experiments2006In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 110, no 4, p. 1830-1836Article in journal (Refereed)
    Abstract [en]

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

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