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  • 1.
    Krivosheeva, Olga
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Interfacial Properties of Film Forming Proteins and their Layer-by-Layer Assembly with Nanoparticles2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

     The aim of this thesis work was to investigate the interfacial properties of film forming proteins, stability of the layers created by them, and their interactions with nanoparticles. Mussel adhesive protein (Mefp-1) and hydrophobins (HFBI and HFBII) were the three main proteins used. HFBI and HFBII are relatively small globular proteins produced by filamentous fungi. They display unusual surface activity, by spontaneously forming films at many interfaces. Mefp-1 is extracted from mussel byssus and posses high ability to strongly attach to different kinds of surfaces. Fundamental understanding of their interfacial properties is of general interest because of the variety of possible applications, for example in food, biomedicine, coatings, etc.

     The adsorption and layer stability studies of HFBI, HFBII, and Mefp-1 at the solid/water interface were studied by means of dual polarization interferometery (DPI). It was observed that the adsorbed amount of HFBII was higher than that of HFBI and the film formed by the former protein was more compact. The adsorption kinetics of the two hydrophobins displayed some unusual features. Further, it was found that layers formed by these proteins partially desorbed when the flow was stopped, and the desorption rate for HFBII was enhanced in the presence of hydrophobins in solution.

      Adsorption of Mefp-1 as a function of solution pH or degree of aggregation in the bulk was investigated. Adsorbed amount of non-aggregated Mefp-1 on silicon oxynitride increased with increasing buffer pH, but the resulting film was not more compact. Adsorption of slightly aggregated Mefp-1 resulted in higher adsorbed amount and formation of denser layer. Initial adsorption kinetics studies revealed almost no pH dependence of the non-aggregated mussel adhesive protein, but the kinetics was slowed down by presence of aggregates in the bulk solution. Moreover, the effect of ionic strength and low pH on preadsorbed Mefp-1 layer was investigated, and it was found that the protein layer exhibits higher resistance towards desorption than a synthetic polyelectrolyte with similar charge density.

     Finally, physical and nanomechanical properties of composite films consisting of Mefp-1 and ceria nanoparticles were examined. For fabrication of these films the layer-by-layer approach was used. Quartz crystal microbalance with dissipation (QCM-D) was utilized to measure sensed mass and visco-elastic properties of adsorbed layers. Atomic force microscopy (AFM) techniques, including peak force quantitative nanomechanical mapping (Peak Force QNM) and contact mode AFM, were used for measuring physical, mechanical and robustness properties of nanocomposite films in air. Independently on the number of layers an almost linear growth of sensed mass was observed while the total dissipation values increases after six steps. Moreover, increase in Mefp-1 concentration during deposition resulted in formation of a more rigid layer, by comparison with lower concentration. The robustness of the nanocomposite layer showed that at low pressures (about 16 MPa) plastic deformation occurs and increase in load result in abrasion of the layers at about 80 MPa.

  • 2.
    Krivosheeva, Olga
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Dedinaite, Andra
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Applied Physical Chemistry.
    Claesson, Per M.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Adsorption of Mefp-1: Influence of pH on adsorption kinetics and adsorbed amount2012In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 379, p. 107-113Article in journal (Refereed)
    Abstract [en]

    Mussel adhesive proteins have received considerable attention due to their ability to bind strongly to many surfaces under water. Key structural features of these proteins include a large number of 3,4-dihydroxyphenyl-L-alanin (DOPA) and positively charged lysine residues. We elucidate the effects of solution pH, in the pH range 3-9, on adsorption kinetics, adsorbed amount, and layer structure on silicon oxynitride by employing Dual Polarization Interferometry. As a comparison, the cationic globular protein lysozyme was also investigated. The zeta-potential of the silicon oxynitride substrate was determined as a function of pH, and the isoelectric point was found to be below pH 3. Mefp-1 is positively charged at pH < 10, and thus, the protein is expected to have an electrostatic attraction for the surface at all pH values investigated. The adsorbed amount and the initial adsorption rate were found to increase with solution pH, and no significant desorption occurred due to rinsing with pure water. The layer thickness after rinsing was 3-4 nm, except at pH 3, where the adsorption was limited to a small amount. Covalent cross-linking of the Mefp-1 layer with NaIO4 resulted in a small but significant compaction and increase in refractive index of the layer. The results are discussed in terms of the role of DOPA and electrostatic interactions for the adsorption of Mefp-1 to silicon oxynitride. (C) 2012 Elsevier Inc. All rights reserved.

  • 3.
    Krivosheeva, Olga
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Dédinaité, Andra
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Claesson, Per Martin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Salt- and pH-induced desorption: Comparison between non-aggregated and aggregated mussel adhesive protein, Mefp-1, and a synthetic cationic polyelectrolyte2013In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 408, p. 82-86Article in journal (Refereed)
    Abstract [en]

    Mussel adhesive proteins are of great interest in many applications due to their ability to bind strongly to many types of surfaces under water. Effective use such proteins, for instance the Mytilus edulis foot protein - Mefp-1, for surface modification requires achievement of a large adsorbed amount and formation of a layer that is resistant towards desorption under changing conditions. In this work we compare the adsorbed amount and layer properties obtained by using a sample containing small Mefp-1 aggregates with that obtained by using a non-aggregated sample. We find that the use of the sample containing small aggregates leads to higher adsorbed amount, larger layer thickness and similar water content compared to what can be achieved with a non-aggregated sample. The layer formed by the aggregated Mefp-1 was, after removal of the protein from bulk solution, exposed to aqueous solutions with high ionic strength (up to 1 M NaCl) and to solutions with low pH in order to reduce the electrostatic surface affinity. It was found that the preadsorbed Mefp-1 layer under all conditions explored was significantly more resistant towards desorption than a layer built by a synthetic cationic polyelectrolyte with similar charge density. These results suggest that the non-electrostatic surface affinity for Mefp-1 is larger than for the cationic polyelectrolyte.

  • 4.
    Krivosheeva, Olga
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Dédinaité, Andra
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Linder, Markus B.
    Tilton, Robert D.
    Claesson, Per Martin
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Kinetic and Equilibrium Aspects of Adsorption and Desorption of Class II Hydrophobins HFBI and HFBII at Silicon Oxynitride/Water and Air/Water Interfaces2013In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 29, no 8, p. 2683-2691Article in journal (Refereed)
    Abstract [en]

    Hydrophobins are relatively small globular proteins produced by filamentous fungi. They display unusual high surface activity and are implied as mediators of attachment to surfaces, which has resulted in high scientific and technological interest. In this work we focus on kinetic and equilibrium aspects of adsorption and desorption properties of two representatives of class II hydrophobins, namely HFBI and HFBII, at a negatively charged hydrophilic solid/water interface and at the air/water interface. The layers formed at the air/liquid interface were examined in a Langmuir trough, whereas layers formed at the solid/liquid interface were studied using dual polarization interferometry (DPI) under different flow conditions. For comparison, another globular protein, lysozyme, was also investigated. It was found that both the adsorbed amount and the adsorption kinetics were different for HFBI and HFBII, and the adsorption behavior of both hydrophobins on the negatively charged surface displayed some unusual features. For instance, even though the adsorption rate for HFBI was slowed down with increasing adsorbed amount as expected from packing constraints at the interface, the adsorption kinetics curves for HFBII displayed a region indicating adsorption cooperativity. Further, it was found that hydrophobin layers formed under flow partly desorbed when the flow was stopped, and the desorption rate for HFBII was enhanced in the presence of hydrophobins in solution.

  • 5.
    Krivosheeva, Olga
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Sababi, Majid
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Dédinaité, Andra
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Claesson, Per M.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Nanostructured Composite Layers of Mussel Adhesive Protein and Ceria Nanoparticles2013In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 29, no 30, p. 9551-9561Article in journal (Refereed)
    Abstract [en]

    Mussel adhesive proteins are known for their high affinity to a range of different surfaces, and they therefore appear as ideal candidates for producing thin inorganic-organic composite films with high robustness. In this work we explore the possibility of making cohesive films utilizing layer-by-layer deposition of the highly positively charged mussel adhesive protein, Mefp-1, and negatively charged ceria nanoparticles. This particular material combination was chosen due to recent findings that such films provide good corrosion protection. Quartz crystal microbalance with dissipation monitoring (QCM-D) was used for following the film formation process in situ on silica surfaces. A close to linear growth of the film with number of deposited layers was found for up to 18 deposition steps, the highest number of depositions investigated in this work. The Mefp-1 concentration during film deposition affected the film properties, where a higher protein concentration resulted in a stiffer film. It was also found that the added mass could be amplified by using a Mefp-1 solution containing small aggregates. The surface nanomechanical properties of dried multilayer films were investigated using peak force QNM (quantitative nanomechanical mapping) in air. Homogeneous surface coverage was found under all conditions explore, and the Young's modulus of the outer region of the coating increased when a higher Mefp-1 concentration was used during film deposition. The nature of the outermost surface layer was found to significantly affect the surface nanomechanical properties. The abrasion resistance of the coating was measured by using controlled-force contact mode AFM.

  • 6.
    Laurell Lyne, Åsa
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Highway and Railway Engineering.
    Krivosheeva, Olga
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Birgisson, Björn
    KTH, School of Architecture and the Built Environment (ABE), Transport Science, Highway and Railway Engineering.
    Adhesion between bitumen and aggregate: implementation of spectroscopic ellipsometry characterisation and estimation of Hamaker's constant2013In: Materials and Structures, ISSN 1359-5997, E-ISSN 1871-6873, Vol. 46, no 10, p. 1737-1745Article in journal (Refereed)
    Abstract [en]

    Refractive indices of seven bitumen samples and three aggregates (typical components in flexible asphalt pavement) were determined by ellipsometry in order to predict bitumen-aggregate adhesion and bitumen-bitumen cohesion using Hamaker’s constant.

    Hamaker’s constant according to Lifshitz was introduced to the asphalt field by two of the authors to describe and estimate van der Waal’s interaction and bitumen–aggregate adhesion. Lifshitz used the refractive index to estimate the dispersive non-polar van der Waal’s interaction component of adhesion, the predominant component in adhesion between minerals and bituminous binder. The impact of an intervening thin medium such as air or water on the adhesion can be estimated using Hamaker’s coefficient, which in turn can be related to stripping potential.

    The bitumen binders studied were delivered as a paving grade 70/100 according to EN 12591:2009 and came from different bitumen suppliers. The three aggregates studied were two types of granite and one diabase.

    It is concluded from the measurement of refractive indices and calculations of the Hamaker’s constant that there was a larger spread in refractive index among the three aggregate samples studied than among the seven bitumen samples.

  • 7.
    Sababi, Majid
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Zhang, Fan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Krivosheeva, Olga
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Forslund, Mattias
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Pan, Jinshan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Claesson, Per M.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Dédinaité, Andra
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface and Corrosion Science.
    Thin Composite Films of Mussel Adhesive Proteins and Ceria Nanoparticles on Carbon Steel for Corrosion Protection2012In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 159, no 8, p. C364-C371Article in journal (Refereed)
    Abstract [en]

    Thin composite films of the mussel adhesive proteins (Mefp-1) and ceria nanoparticles were deposited on substrate surfaces by alternating immersions. The film formation was studied by quartz crystal microbalance with dissipation (QCM-D) monitoring. Both the changes in frequency and dissipation recorded by QCM-D demonstrate buildup of a composite film of Mefp-1 and nanoceria. Micro-and nanostructure and composition of the film on carbon steel were characterized by optical and atomic force microscopy (AFM), electron probe micro analyzer (EPMA) and confocal Raman microspectroscopy (CRM). Optical and EPMA observations of the film show micron-sized aggregates and AFM imaging of the compact and smooth areas reveal the nanostructure. EPMA elemental mapping indicates that the micron-sized aggregates are rich in ceria and Mefp-1, whereas CRM analysis shows the presence of Mefp-1-Fe complexes in the film. Corrosion protection of the composite film on carbon steel was investigated by electrochemical impedance spectroscopy and potentiodynamic polarization measurements in NaCl solution, and compared with Mefp-1 added in the solution as an inhibitor. The measurements show that the composite film provides a higher corrosion resistance compared with Mefp-1 added as inhibitor. The corrosion resistance increases with exposure time and approaches a high level.

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