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  • 1.
    Abtahi, Jahan
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Orthopaedics and Sports Medicine. Linköping University, Faculty of Health Sciences.
    Tengvall, Pentti
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology. Department of Biomaterials, Institute of Clinical Sciences, Sahlgrenska Academy, Gothenburg, Sweden.
    Aspenberg, Per
    Linköping University, Department of Clinical and Experimental Medicine, Orthopaedics and Sports Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Orthopaedic Centre, Department of Orthopaedics Linköping.
    Bisphosphonate coating might improve fixation of dental implants in the maxilla: A pilot study2010In: International Journal of Oral and Maxillofacial Surgery, ISSN 0901-5027, E-ISSN 1399-0020, Vol. 39, no 7, p. 673-677Article in journal (Refereed)
    Abstract [en]

    This pilot study evaluates the clinical stability of bisphosphonate-coated dental implants placed using a two-stage surgical procedure in five patients. Each patient received seven regular Branemark implants, one of which was coated with bisphosphonate in a fibrinogen matrix. The coated implant was inserted where the bone was expected to have the least favourable quality. The level of the marginal bone around each implant was measured by intraoral periapical radiographs and implant stability was recorded using resonance frequency measurements. Frequency values (ISQ) were obtained peroperatively before flap closure and after 6 months at abutment connection. At abutment connection the bisphosphonate-coated implants were removed en bloc in two patients for histological examination. An animal experiment had previously confirmed that gamma-sterilization did not reduce bioactivity of the bisphosphonate coating. In each patient, the bisphosphonate-coated implant showed the largest improvement in ISQ level of all implants. Their values at the start tended to be lower, and the absolute value at 6 months did not differ. No complications occurred with the coated implants. Histology showed no abnormalities. Improvement in ISQ values was an expected effect of the bisphosphonate coating, but could be due to the choice of insertion site. This finding warrants a randomized blinded study.

  • 2.
    Andersson, Therese
    et al.
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Agholme, Fredrik
    Linköping University, Department of Clinical and Experimental Medicine, Orthopaedics and Sports Medicine. Linköping University, Faculty of Health Sciences.
    Aspenberg, Per
    Linköping University, Department of Clinical and Experimental Medicine, Orthopaedics and Sports Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Orthopaedic Centre, Department of Orthopaedics Linköping.
    Tengvall, Pentti
    Gothenburg University.
    Surface immobilized zoledronate improves screw fixation in rat bone: A new method for the coating of metal implants2010In: JOURNAL OF MATERIALS SCIENCE-MATERIALS IN MEDICINE, ISSN 0957-4530, Vol. 21, no 11, p. 3029-3037Article in journal (Refereed)
    Abstract [en]

    Previous studies show that surface immobilized bisphosphonates improve the fixation of stainless steel screws in rat tibia after 2-8 weeks of implantation. We report here about the immobilization of a potent bisphosphonate, zoledronate, to crosslinked fibrinogen by the use of another technique, i.e. ethyl-dimethyl-aminopropylcarbodiimide (EDC)/imidazole immobilization. Bone fixation of zoledronate-coated screws was compared to screws coated with crosslinked fibrinogen only and ditto with EDC/N-hydroxy-succinimide immobilized pamidronate. Fixation in rat tibia was evaluated by a pull-out test at either 2 or 6 weeks after implantation. Both bisphosphonate coatings increased the pull-out force at both time points, and zoledronate showed a significantly higher pull-out force than pamidronate. To further evaluate the new coating technique we also performed a morphometric study, focusing on the area surrounding the implant. The zoledronate coating resulted in an increased bone density around the screws compared to controls. No pronounced increase was seen around the pamidronate coated screws. Together, the results demonstrate the possibility of obtaining a significant local therapeutic effect with minute amounts of surface immobilized zoledronate.

  • 3.
    Arvidsson, Sara
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Askendal, Agneta
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Lindahl, Tomas
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Chemistry.
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Detection of surface bound complement at increasing serum anticoagulant concentrations2008In: Colloids and Surfaces B: Biointerfaces, ISSN 0927-7765, E-ISSN 1873-4367, Vol. 62, p. 214-219Article in journal (Refereed)
    Abstract [en]

      

  • 4.
    Arvidsson, Sara
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Askendal, Agneta
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Blood plasma contact activation on silicon titanium and aluminium2007In: Biomaterials, ISSN 0142-9612, E-ISSN 1878-5905, Vol. 28, p. 1346-1354Article in journal (Refereed)
    Abstract [en]

       

  • 5.
    Arwin, Hans
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Optics .
    Askendal, Agneta
    Linköping University, Department of Physics, Chemistry and Biology.
    Berlind, Torun
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Optics .
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Thompson, Dan W
    Department of electrical engineering University of Nebraska.
    Tiwald, T
    Woollam, John A.
    Department of electrical engineering University of Nebraska.
    Infrared ellipsometry studies of temperature effects on multilayers of ANTI-human serum albumin and its antigen2005In: E-MRS,2005, 2005Conference paper (Other academic)
  • 6.
    Arwin, Hans
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Optics . Linköping University, The Institute of Technology.
    Askendal, Agneta
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Tengvall, Pentti
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Thompson, Daniel W.
    University of Nebraska, Lincoln, NE, USA.
    Woollam, John A.
    J. A. Woollam Co., Inc, Lincoln, NE, USA.
    Infrared ellipsometry studies of thermal stability of protein monolayers and multilayers2008In: Physica Status Solidi. C: Current Topics in Solid State Physics, ISSN 1862-6351, Vol. 5, no 5, p. 1438-1441Article in journal (Refereed)
    Abstract [en]

    Methodology for studies of effects of heating multilayers of human serum albumin (HSA) and anti-HSA is presented. Multilayers of anti-HSA were prepared on silicon substrates and studied with infrared spectroscopic ellipsometry equipped with a heat stage. The refractive index N = n + ik and the layer thickness are determined and the amide bands are analyzed. It is found that HSA/anti-HSA multilayers are stable for shorter times at temperatures above 100 °C, except for small thickness changes. Also pilot studies of effects of heating monolayers of proteins adsorbed on gold substrates is presented.

  • 7.
    Arwin, Hans
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Optics .
    Gavutis, M
    Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden Vilnius State Univ, Dept Phys, Vilnius, Lithuania Univ Nebraska, Ctr Microelect & Opt Mat Res, Lincoln, NE 68588 USA Univ Nebraska, Dept Elect Engn, Lincoln, NE 68588 USA.
    Gustafsson, J
    Schultzberg, M
    Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden Vilnius State Univ, Dept Phys, Vilnius, Lithuania Univ Nebraska, Ctr Microelect & Opt Mat Res, Lincoln, NE 68588 USA Univ Nebraska, Dept Elect Engn, Lincoln, NE 68588 USA.
    Zangooie, S
    Linkoping Univ, Dept Phys & Measurement Technol, SE-58183 Linkoping, Sweden Vilnius State Univ, Dept Phys, Vilnius, Lithuania Univ Nebraska, Ctr Microelect & Opt Mat Res, Lincoln, NE 68588 USA Univ Nebraska, Dept Elect Engn, Lincoln, NE 68588 USA.
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Protein adsorption in thin porous silicon layers2000In: Physica status solidi. A, Applied research, ISSN 0031-8965, E-ISSN 1521-396X, Vol. 182, no 1, p. 515-520Article in journal (Refereed)
    Abstract [en]

    Porous silicon layers with thicknesses in the range 100-400 nm and average porosities in the range 38-71% were prepared by electrochemical anodization. Variable angle spectroscopic ellipsometry was used to characterize the microstructure of the layers before protein adsorption. In-situ ellipsometry was then employed tr, monitor the kinetics of fibrinogen and human serum albumin adsorption. At steady state new ellipsometric spectra were recorded to determine the total amount of adsorbed protein. Under the experimental conditions used here, the protein molecules were found to adsorb in the outermost part of the porous layer. However, human serum albumin penetrated into the porous silicon matrix at low pH and high porosity. From a methodological point of view it was found that spectroscopic ellipsometry is an appropriate tool for characterization of the microstructure of porous silicon layers and for in-situ monitoring of protein adsorption in such layers including depth profiling.

  • 8.
    Benesch, Johan
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Askendal, Agneta
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Quantification of adsorbed human serum albumin at solid interfaces: A comparison between radioimmunoassay (RIA) and simple null ellipsometry2000In: Colloids and Surfaces B: Biointerfaces, ISSN 0927-7765, E-ISSN 1873-4367, Vol. 18, no 2, p. 71-81Article in journal (Refereed)
    Abstract [en]

    Radioimmunoassay (RIA) and null ellipsometry are two common methods to quantify adsorbed proteins. However, the accuracy of null ellipsometry with a constant protein refractive index (n=1.465, k=0) at ?=632.8 nm has this far not been explored. The present study compared the methods, and the degree of agreement between the simplified single wavelength null ellipsometry and RIA to quantify adsorbed proteins was explored on different surfaces. The quantification methods agreed well when Angstrom smooth hydrophilic or hydrophobic silicon surfaces, and freshly radio-labelled proteins were used. Some discrepancies were noted when either rough surface or stored and aged labelled proteins were used. The differences decreased when the aged protein solution was equilibrated with freshly dissolved proteins at room temperature (RT) for a few hours prior to the surface incubations. Significant differences were also noted between the methods when albumin was adsorbed at it's iso-electric point (pH 4.8). Copyright (C) 2000 Elsevier Science B.V.

  • 9.
    Benesch, Johan
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Askendal, Agneta
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    The determination of thickness and surface mass density of mesothick immunoprecipitate layers by null ellipsometry and protein 125Iodine labeling2002In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 249, no 1, p. 84-90Article in journal (Refereed)
    Abstract [en]

    The aim of the present study was to ellipsometrically determine the thickness and surface mass density in air for up to 110-nm-thick organic layers made of alternatingly deposited layers of HSA and polyclonal anti-HSA on hydrophobic silicon. The ellipsometrically determined thickness was compared to that obtained by AFM and the deposited surface mass density calibrated with 125I-labeled proteins. The results indicate a good agreement in protein layer thickness between AFM and ellipsometry when the protein film refractive index Nfilm = 1.5 -0i, although then the calculated surface mass density from the ellipsometry data became grossly overestimated by the Cuypers one-component formula. A good agreement in the surface mass density was obtained when the M/A ratio in this formula was lowered from 4.14 to 2.35. This approach indicates a convenient means of determining the refractive indices and surface mass densities of mesothick organic layers proteins on solid supports. © 2002 Elsevier Science (USA).

  • 10.
    Benesch, Johan
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Svedhem, S.
    Svensson, Stefan
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Organic Chemistry .
    Valiokas, Ramunas
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Liedberg, Bo
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics .
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Protein adsorption to oligo(ethylene glycol) self-assembled monolayers: Experiments with fibrinogen, heparinized plasma, and serum2001In: Journal of Biomaterials Science. Polymer Edition, ISSN 0920-5063, E-ISSN 1568-5624, Vol. 12, no 6, p. 581-597Article in journal (Refereed)
    Abstract [en]

    Low protein adsorption is believed advantageous for blood-contacting materials and ethylene glycols (EG)-based polymeric compounds are often attached to surfaces for this purpose. In the present study, the adsorption of fibrinogen, serum, and plasma were studied by ellipsometry on a series of well-defined oligo(EG) terminated alkane-thiols self-assembled on gold. The layers were prepared with compounds of the general structure HS-(CH2)15-CONH-EGn, where n = 2, 4, and 6. Methoxy-terminated tri(EG) undecanethiol and hydroxyl-terminated hexadecanethiol self-assembled monolayers (SAMs) were used as references. The results clearly demonstrate that the adsorption depends on the experimental conditions with small amounts of fibrinogen adsorbing from a single protein solution, but larger amounts of proteins from serum and plasma. The adsorption of fibrinogen and blood plasma decreased with an increasing number of EG repeats and was temperature-dependent. Significantly less serum adsorbed to methoxy tri(EG) than to hexa(EG) and more proteins remained on the latter surface after incubation in a sodium dodecyl sulfate (SDS) solution, indicating a looser protein binding to the methoxy-terminated surface. All surfaces adsorbed complement factor 3(C3) from serum and plasma, although no surface-mediated complement activation was observed. The present study points to the importance of a careful choice of the protein model system before general statements regarding the protein repellant properties of potential surfaces can be made.

  • 11.
    Benesch, Johan
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Blood protein adsorption onto chitosan2002In: Biomaterials, ISSN 0142-9612, E-ISSN 1878-5905, Vol. 23, no 12, p. 2561-2568Article in journal (Refereed)
    Abstract [en]

    Chitosan was recently indicated to enhance osteogenesis, improve wound healing but to activate the coagulation and the complement systems. In the present study approximately 10nm thick chitosan film were prepared on aminopropyltriethoxysilane (APTES) coated silicon. The surfaces were incubated in serum or plasma and subsequently in antibodies towards key complement and contact activation of coagulation proteins. The deposited amounts were compared with those on hydrophilic and hydrophobic silicon, APTES and IgG coated reference samples. Although large amounts of serum deposited to chitosan only a weak transient activation of the complement system and no activation of the intrinsic pathway was observed. Upon acetylation the chitosan layer became a strong activator of the alternative pathway of the complement. After incubation in human plasma anti-fibrinogen deposited onto chitosan but not onto the acetylated chitosan, a finding that may explain previous observations of procoagulant activity by chitosan. Copyright © 2002 Elsevier Science Ltd.

  • 12.
    Berg, Cecilia
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Hammarström, Sven
    Linköping University, Department of Biomedicine and Surgery, Division of cell biology. Linköping University, Faculty of Health Sciences.
    Herbertsson, Helena
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Lindström, Eva
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Svensson, Ann-Charlotte
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Söderström, Mats
    Linköping University, Department of Biomedicine and Surgery, Division of cell biology. Linköping University, Faculty of Health Sciences.
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics.
    Bengtsson, Torbjörn
    Linköping University, Department of Medicine and Care, Pharmacology. Linköping University, Faculty of Health Sciences.
    Platelet-induced growth of human fibroblasts is associated with an increased expression of 5-lipoxygenase2006In: Thrombosis and Haemostasis, ISSN 0340-6245, Vol. 96, no 5, p. 652-659Article in journal (Refereed)
    Abstract [en]

    Proliferation of fibroblasts is vital for adequate wound healing but is probably also involved in different hyperproliferative disorders such as atherosclerosis and cancer. The regeneration of tissue usually starts with coagulation, involving release of mitogenic and inflammatory factors from activated platelets. This study focuses on the role of eicosanoids in the proliferative effects of platelets on human fibroblasts. We show that the phospholipase A2 inhibitor 7,7-dimethyl-5,8-eicosadienoic acid (DMDA), the combined cyclooxygenase (COX) and lipoxygenase (LOX) inhibitor 5,8,11,14-eicosatetraynoic acid (ETYA) and the LOX inhibitor 5,8,11-eicosatriynoic acid (ETI) block the platelet-induced proliferation of serum starved subconfluent human fibroblasts. Anti-proliferative effects were also obtained by specific inhibition of 5-LOX with 5,6-dehydro arachidonic acid (5,6-dAA), whereas the 12-LOX inhibitor cinnamyl-3,4-dihydroxy-α-cyanocinnamate (CDC) did not affect the platelet-stimulated growth of fibroblasts. The expression of 5-LOX was analyzed by reverse-transcriptase-mediated PCR (RT-PCR), Western blotting and HPLC. 5-LOX message and protein was detected in fibroblasts but not in platelets. Incubation with platelets markedly increased, already after one hour, the expression of 5-LOX in the fibroblast culture. The increased 5-LOX activity was associated with an elevated level of the 5-LOX metabolite 5-hydroxyeicosatetraenoic acid (5-HETE) reaching its maximum after 1-2 hours of co-incubation of fibroblasts and platelets. The 5-HETE production was reduced by the inhibitors DMDA, ETYA and ETI. In conclusion, this study suggests that platelet-stimulated proliferation of fibroblasts is mediated by an increased 5-LOX activity, which supports recent findings indicating a crucial role for this enzyme in proliferative disorders such as atherosclerosis. © 2006 Schattauer GmbH, Stuttgart.

  • 13.
    Berlind, Torun
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Optics .
    Poksinski, Michal
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Optics .
    Hultman, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Arwin, Hans
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Optics .
    Adsorption of human serum albumin on carbon nitride films studied with in-situ ellipsometry2005In: American Vacuum Society 52 Int Symposium and Exhibition,2005, 2005Conference paper (Other academic)
  • 14.
    Berlind, Torun
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Optics .
    Poksinski, Michal
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Optics .
    Hultman, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Arwin, Hans
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Optics .
    Bioadsorption studies on carbon nitride films using in-situ ellipsometry2005In: E-MRS spring meeting,2005, 2005Conference paper (Other academic)
  • 15.
    Berlind, Torun
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Optics .
    Poksinski, Michal
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Optics .
    Hultman, Lars
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics.
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Arwin, Hans
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Optics .
    Protein Adsorption on Carbon Nitride Films Studied with in situ Ellipsometry2007In: 4th International Conference on Spectroscopic Ellipsometry,2007, Linköping: Linköpings universitet , 2007, p. 246-Conference paper (Refereed)
  • 16.
    Berlind, Torun
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Optics . Linköping University, The Institute of Technology.
    Poksinski, Michal
    Roxen IS AB, S-581 05 Linköping, Sweden.
    Tengvall, Pentti
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics . Linköping University, The Institute of Technology.
    Arwin, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Applied Optics . Linköping University, The Institute of Technology.
    Formation and cross-linking of fibrinogen layers monitored with in situ spectroscopic ellipsometry2010In: Colloids and Surfaces B: Biointerfaces, ISSN 0927-7765, E-ISSN 1873-4367, Vol. 75, no 2, p. 410-417Article in journal (Other academic)
    Abstract [en]

    Thick matrices of fibrinogen with incorporation of a matrix metalloproteinaseinhibitor were covalently bonded on functionalized silicon surfaces using an ethyl-3-dimethyl-aminopropyl-carbodiimide and N-hydroxy-succinimide affinity ligand couplingchemistry. The growth of the structure was followed in situ using dynamic ellipsometryand characterized at steady-state with spectroscopic ellipsometry. The growth wascompared with earlier work on ex situ growth of fibrinogen layers studied by singlewavelength ellipsometry. It is found that in situ growth and ex situ growth yield differentstructural properties of the formed protein matrix. Fibrinogen matrices with thicknessesup to 58 nm and surface mass densities of 1.6 μg/cm2 have been produced.

  • 17.
    Berlind, Torun
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Optics . Linköping University, The Institute of Technology.
    Tengvall, Pentti
    Department of Biomaterials, Institute of Surgical Sciences, The Sahlgrenska Academy, University of Gothenburg.
    Hultman, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, The Institute of Technology.
    Arwin, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Applied Optics . Linköping University, The Institute of Technology.
    Protein adsorption on thin films of carbon and carbon nitride monitored with in situ ellipsometry2011In: ACTA BIOMATERIALIA, ISSN 1742-7061, Vol. 7, no 3, p. 1369-1378Article in journal (Refereed)
    Abstract [en]

    Amorphous carbon and amorphous, graphitic and fullerene-like carbon nitride thin filmswere deposited by reactive magnetron sputtering and optically characterized withspectroscopic ellipsometry. The films were exposed to human serum albumin and theadsorption was monitored in situ using dynamic ellipsometry. From the ellipsometric data theadsorbed amount of proteins was quantified in terms of surface mass density using de Feijter'smodel. The results indicated larger adsorption of proteins onto the amorphous films comparedto the films with a more ordered microstructure. Complementary studies with labeled HSAusing radioimmunoassay showed up to 6 times higher protein adsorption compared to theellipsometry measurement which partly might be explained by differences in surfaceroughness (from 0.3 to 13 nm) among the films. The elutability of adsorbed labeled HSAusing unlabeled HSA and sodium dodecyl sulphate was low compared to a silicon reference.In addition, the four types of films were incubated in blood plasma followed by antifibrinogen,anti-HMWK or anti-C3c revealing the materials response to complement andcontact activation. Three of the films indicated immunoactivity, whereas the amorphouscarbon showed less immunoactivity compared to a titanium reference. All films showedindications of a stronger ability to initiate the intrinsic pathway of coagulation, compared tothe reference. Finally, the surfaces bone bonding ability was investigated by examination oftheir ability to form calcium phosphate (CaP) crystals in a simulated body fluid, with a-CNxdepositing most CaP after 21 days of incubation.

  • 18.
    Brunette, Donald M,
    et al.
    Faculty of Dentistry University of British Columbia, Vancouver, Canada.
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics.
    Textor, Marcus
    Dept. of Materials Swiss Federal Inst. of Technology, Zurich, Switzerland.
    Thomsen, Peter
    Inst. of Anatomy Cell Biology Göteborgs universitet.
    Titanium in Medicine: material science, surface science, engineering, biological responses and medical applications2001Book (Other academic)
    Abstract [en]

       This comprehensive book provides state-of-the-art scientific and technical information in a clear format and consistent structure making it suitable for formal course work or self-instruction. The authors are drawn not only from academic institutions but also from industry, so that practical aspects of implant fabrication and material handling are covered that are often lacking in biomaterials texts. Besides readers with a general interest in biomaterials, the book will interest materials investigators, surgeons and dentists using titanium implants, medical scientists and engineers, as well as lecturers at universities or institutes who would benefit by having ready access to authoritative information on the use of titanium for implants, devices and instruments. More information: http://www.titaniuminmedicine.com.

  • 19.
    Ericsson, Emma
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Faxälv, Lars
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Chemistry.
    Weissenrieder, Anna
    St Paul, USA.
    Askendal, Agneta
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Lindahl, Tomas
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Tengvall, Pentti
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Glycerol monooleate-blood interactions2009In: Colloids and Surfaces B: Biointerfaces, ISSN 0927-7765, E-ISSN 1873-4367, Vol. 68, no 1, p. 20-26Article in journal (Refereed)
    Abstract [en]

    In the present study the initial blood compatibility of glycerol monooleate (GMO)-coated surfaces was evaluated after deposition to surfaces and in bulk. The model surface was silica onto which multiple layers of fibrinogen or human serum albumin (HSA) was immobilized. The protein-coated surfaces were subsequently dip-coated in GMO in ethanol and used for blood plasma and whole blood experiments. The characterization methods included null ellipsometry, scanning electron microscopy, imaging of coagulation, hemolysis test and whole blood coagulation time by free oscillation rheometry.

    The results showed a GMO film thickness of approximately 350 angstrom (similar to 4 mu g/cm(2)) upon dip-coating in ethanolic solution. A major part of the deposited layer detached in aqueous solutions, especially during shear conditions. The coagulation time on GMO was significantly prolonged compared to that on HSA coated silica. Whole blood tests showed that GMO is a very weak hemolytic agent. Deposited GMO detached easily from surfaces upon rinsing or shearing, although a stable layer with undefined phase structure and a thickness of 50-70 angstrom remained on HSA and fibrinogen precoated surfaces. This indicates that GMO has stronger adhesive forces to its substrate compared to the cohesive forces acting within the bulk GMO. The ability of GMO to detach from itself and tentatively form micelles or lipid bilayers when subjected to flowing blood may be of use in extravascular applications. It is concluded that GMO results in weak blood activation, and the material may in spite of this be suitable in selected biomaterial applications, especially as a biosealant and in colloidal dispersions.

  • 20.
    Erlandsson, Ragnar
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Chemical and Optical Sensor Systems. Linköping University, Faculty of Science & Engineering.
    Elwing, Hans
    Eriksson, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Chemical and Optical Sensor Systems. Linköping University, Faculty of Science & Engineering.
    Olsson, Lars
    Linköping University, Department of Medical and Health Sciences. Tekniska högskolan.
    Tengvall, Pentti
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Wigren, Roger
    Welin Klintström, Stefan
    Linköping University, Department of Physics, Chemistry and Biology, Chemical and Optical Sensor Systems. Linköping University, Faculty of Science & Engineering.
    Lundström, Ingemar
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Scanning force microscopy - examples of applications to surface chemistry1992In: Progress in Colloid and Polymer Science, ISSN 0340-255X, E-ISSN 1437-8027, Vol. 88, p. 154-161Article in journal (Refereed)
    Abstract [en]

    Some recent results from the scanning force microscopy activity at our laboratory are presented. A brief description of attractive mode force microscopy is followed by a discussion of the following examples: O2/H2-induced morphology changes in thin palladium films, structure of spin cast polysulfone films, fibrinogen adsorption on hydrophobic SiO2, and force measurements on hydrophobic/hydrophilic substrates.

  • 21.
    Faxälv, Lars
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Chemistry.
    Ramström, Sofia
    Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, Dublin, Ireland.
    Soutukorva, Kristina
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Tengvall, Pentti
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Lindahl, Tomas L.
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Chemistry.
    The role of coagulation factor XII in propagation of coagulationManuscript (preprint) (Other academic)
    Abstract [en]

    The physiological relevance and function of coagulation factor XII (FXII), the first zymogen in the intrinsic pathway, has for a long time been a matter of debate. The aim of this study was to shed some light on the role of factor XII in thrombus formation with a focus on its effect during the propagation phase of coagulation. In order to study propagation of coagulation we utilized a new imaging method to measure propagation rates from an activating surface in both platelet-free plasma and platelet-rich plasma. The most essential results revealed that both FXII and its substrate FXI are located on the surface of activated platelets. The surface of preexisting clots does not support coagulation in a FXII dependent manner. However, we found strong evidence for an accelerated propagation of tissue factor initiated coagulation when contact activation of FXII simultaneously occurred in the proximity. In vivo sources for contact activation may be exposed subendothelial collagen as well as soluble and cell derived poly-anions. If such in vivo contact activation of FXII occurs, even though moderate, it could contribute to in vivo thrombus growth rate and thus be of pathophysiological importance.

  • 22.
    Faxälv, Lars
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Chemistry.
    Tengvall, Pentti
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics . Linköping University, The Institute of Technology.
    Lindahl, Tomas L
    Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Chemistry.
    Imaging of blood plasma coagulation and its propagation at surfaces2008In: Journal of biomedical materials research. Part A, ISSN 1552-4965, Vol. 85, no 4, p. 1129-1134Article in journal (Refereed)
    Abstract [en]

    A new method utilizing image capture and processing was developed for the analysis of blood plasma coagulation at surfaces. The coagulation was detected in a cuvette by time-lapse image capture of light scattering from the developing fibrin network. By image processing and computer analysis of the captured image data, both early detection of coagulation at the surface and the propagation phase of coagulation could be measured in the same experiment. It is possible to use both platelet-rich plasma (PRP) and platelet-free plasma (PFP) with the method, and thereby study the platelet contribution to both surface coagulation and propagation of coagulation. Two well-known model surfaces, hydrophilic and hydrophobic glass, were used in combination with PRP and PFP to illustrate the method. Hydrophilic glass activated coagulation significantly faster (PRP: 7.0 +/- 1.7 min, PFP: 5.9 +/- 1.2 min, n= 16) than hydrophobic glass (PRP: 50 +/- 14 min, PFP: 65 +/- 32 min, n = 16) in both PRP and PFP. Hydrophilic surfaces showed a faster initial propagation of coagulation adjacent to the surface (mean velocity: 0.14 +/- 0.05 mm/ minute) compared with the propagation observed further out from the surface (mean velocity: 0.05 +/- 0.01 mm/min). The method is very flexible and can be suitable for screening hemocompatibility of biomaterials.

  • 23.
    Goransson, A.
    et al.
    Göransson, A., Department of Biomaterial Science, Institute of Surgical Science, Göteborg University, Göteborg, Sweden, Department of Prosthetic Dentistry/Dental Material Science, Sahlgrenska Academy, Göteborg University, Göteborg, Sweden, Department of Biomaterial Science, Department of Prosthetic Dentistry/Dental Material Science, Göteborg University, SE 405 30 Göteborg, Sweden.
    Gretzer, C.
    Department of Biomaterial Science, Institute of Surgical Science, Göteborg University, Göteborg, Sweden.
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Wennerberg, A.
    Department of Biomaterial Science, Institute of Surgical Science, Göteborg University, Göteborg, Sweden, Department of Prosthetic Dentistry/Dental Material Science, Sahlgrenska Academy, Göteborg University, Göteborg, Sweden.
    Inflammatory response to titanium surfaces with fibrinogen and catalase coatings: An in vitro study2007In: Journal of Biomedical Materials Research - Part A, ISSN 1549-3296, Vol. 80, no 3, p. 693-699Article in journal (Refereed)
    Abstract [en]

    The aim of the present study was to evaluate the possibility to modulate the early inflammatory response in vitro by coating titanium surfaces with candidate proinflammatory (fibrinogen coated turned titanium "Fib") and antiinflammatory proteins (catalase on top of fibrinogen coated turned titanium "Cat"). Additionally, turned titanium surfaces (Ti) were used as controls. The discs were incubated with human mononuclear cells. Adhered cells were investigated with respect to number, viability, differentiation (acute marker 27E10 vs. chronic marker RM3/1), and cytokine production (TNF-a and IL-10), after 24 and 72 h. The results indicated that it is possible to modulate the inflammatory response with protein coatings. However, the strongest inflammatory response, indicated by increased number of adhered cells and release of pro and antiinflammatory mediators, was induced by Cat. Furthermore, the cytokine production on this surface was not sensitive to LPS stimulation. Differentiation measured as the expression of the chronic cell surface marker, dominated after 72 h for all surface modifications and Cat displayed an increased number compared to the others. A decrease in the total number of adhered cells and amounts of TNF-a were observed on all surfaces over time. The cell viability was, in general, high for all tested surfaces. In conclusion, the study proved it possible to influence the early inflammatory response in vitro by immobilizing protein coatings to titanium surfaces. However, the catalase surface demonstrated the strongest inflammatory response, and the possibility to selectively use the potent antiinflammatory capacity of catalase needs to be further evaluated. © 2006 Wiley Periodicals, Inc.

  • 24.
    Goransson, A.
    et al.
    Göransson, A., Department of Biomaterial Science, Institute of Surgical Science, Göteborg University, Göteborg 40530, Sweden, Department of Prosthetic Dentistry/Dental Material Science, Box 412, Göteborg University, Göteborg 40530, Sweden.
    Jansson, Eva
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Wennerberg, A.
    Department of Biomaterial Science, Institute of Surgical Science, Göteborg University, Göteborg 40530, Sweden, Department of Prosthetic Dentistry/Dental Material Science, Box 412, Göteborg University, Göteborg 40530, Sweden.
    Bone formation after 4 weeks around blood-plasma-modified titanium implants with varying surface topographies: An in vivo study2003In: Biomaterials, ISSN 0142-9612, E-ISSN 1878-5905, Vol. 24, no 2, p. 197-205Article in journal (Refereed)
    Abstract [en]

    The aim of the present study was to investigate and compare the stability and bone ingrowth capacity to screw-shaped titanium implants with five different surface treatments. The implants were: (1) standard turned with a thin blood plasma coat (TP), (2) NaOH-etched dito with pore size 0.2-0.3µm (E), (3) NaOH-etched with pore size 0.2-0.3µm and a thin blood plasma coat (EP), (4) electrochemically oxidised with pore size 1-2µm (O), (5) electrochemically oxidised with pore size 1-2µm and a thin blood plasma coat (OP). A total of 66 implants were divided into the above-described five groups and inserted for 4 weeks into tibia and femur of 11 rabbits. The implants were evaluated by resonance frequency (RF) measurements at the time of insertion and removal, and analysed histomorphometrically at removal. The RF measurements showed that the implant stability was lower in soft bone compared to dense and increased with time. No significant differences were observed between the different surface modifications. The histomorphometric analysis revealed no statistically significant differences between the implants regarding bone-to-metal contact (BMC) and bone area inside the threads (BA). The above results indicate that thin blood plasma-coated and non-coated screw-shaped titanium implants with turned, NaOH-etched and electrochemically etched surface profiles integrate similarly to bone at 1 month of implantation. © 2002 Elsevier Science Ltd. All rights reserved.

  • 25.
    Hammarström, Per
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biochemistry. Linköping University, The Institute of Technology.
    Ali, Malik M
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Mishra, Rajesh
    Linköping University, Department of Physics, Chemistry and Biology, Biochemistry. Linköping University, The Institute of Technology.
    Salagic, Belma
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Svensson, Samuel
    AstraZeneca RandD.
    Tengvall, Pentti
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Lundström, Ingemar
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, The Institute of Technology.
    An Auto-Catalytic Surface for Conformational Replication of Amyloid Fibrils-Genesis of an Amyloid World?2011In: Origins of life and evolution of the biosphere, ISSN 0169-6149, E-ISSN 1573-0875, Vol. 41, no 4, p. 373-383Article in journal (Refereed)
    Abstract [en]

    Amyloid fibrils are composed of self assembled stacked peptide or protein molecules folded and trapped in a stable cross-beta-sheet conformation. The amyloid fibrillation mechanism represents an intriguing self-catalyzed process rendering replication of a molecular conformational memory of interest for prebiotic chemistry. Herein we describe how a solid surface can be rendered auto-catalytic for fibrillation of a protein solution. We have discovered that a hydrophobic silicon or glass surface can be made to continuously fibrillate solutions of insulin monomers under stressed conditions (pH 1.6, 65 degrees C). It was found that the surface acts as a platform for the formation of nascent seeds that induce fibril replication on and at the surface. This autocatalytic effect stems from a layer a few insulin molecules thick representing an oligomeric layer of misfolded, conformationally trapped, insulin molecules that rapidly through epitaxial growth catalyze the rate determining step (nucleation) during fibril replication. This autocatalytic layer is generated by the protein-solid surface interaction and conformational changes of the adsorbed protein during exposure at the air-water interface. The resulting autocatalytic surface thus both initiates local conformational molecular self-replication and acts as a reservoir for fibril seeds budding off into solution spreading fibril replication entities to the surrounding medium. The possibility of catalysis of the conformational replication process by minute amounts of nucleation sites located on a recruiting surface can evade the issue of dramatic concentration dependence of amyloidogenesis.

  • 26.
    Hammarström, Per
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biochemistry. Linköping University, The Institute of Technology.
    Ali Malik, Muhammad
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Mishra, Rajesh
    Linköping University, Department of Physics, Chemistry and Biology, Biochemistry. Linköping University, The Institute of Technology.
    Svensson, Samuel
    Linköping University, Department of Medicine and Health Sciences, Pharmacology . Linköping University, Faculty of Health Sciences.
    Tengvall, Pentti
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics . Linköping University, The Institute of Technology.
    Lundström, Ingemar
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics . Linköping University, The Institute of Technology.
    A catalytic surface for amyloid fibril formation2008In: Journal of Physics, Conference Series, ISSN 1742-6588, E-ISSN 1742-6596, Vol. 100Article in journal (Refereed)
    Abstract [en]

    A hydrophobic surface incubated in a solution of protein molecules (insulin monomers) was made into a catalytic surface for amyloid fibril formation by repeatedly incubate, rinse and dry the surface. The present contribution describes how this unexpected transformation occurred and its relation to rapid fibrillation of insulin solutions in contact with the surface. A tentative model of the properties of the catalytic surface is given, corroborated by ellipsometric measurements of the thickness of the organic layer on the surface and by atomic force microscopy. The surfaces used were spontaneously oxidized silicon made hydrophobic through treatment in dichlorodimethylsilane.

  • 27.
    Hansson, Kenny
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Johansen, Knut
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Wetterö, Jonas
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Rheumatology.
    Klenkar, Goran
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Sensor Science and Molecular Physics.
    Benesch, Johan
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Lundström, Ingemar
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics.
    Lindahl, Tomas
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Division of clinical chemistry. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Chemistry.
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics.
    Surface plasmon resonance detection of blood coagulation and platelet adhesion under venous and arterial shear conditions2007In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 23, no 2, p. 261-268Article in journal (Refereed)
    Abstract [en]

    A surface plasmon resonance (SPR) based flow chamber device was designed for real time detection of blood coagulation and platelet adhesion in platelet rich plasma (PRP) and whole blood. The system allowed the detection of surface interactions throughout the 6 mm length of the flow chamber. After deposition of thromboplastin onto a section of the sensor surface near the inlet of the flow chamber, coagulation was detected downstream of this position corresponding to a SPR signal of 7 to 8 mRIU (7 to 8 ng/mm2). A nonmodified control surface induced coagulation 3.5 times slower. Platelet adhesion to gold and fibrinogen coated surfaces in the magnitude of 1.25 and 1.66 mRIU was also shown with platelets in buffer, respectively. SPR responses obtained with PRP and whole blood on surfaces that were methylated or coated with von Willebrand factor (vWF), fibrinogen, or collagen, coincided well with platelet adhesion as observed with fluorescence microscopy in parallel experiments. The present SPR detection equipped flow chamber system is a promising tool for studies on coagulation events and blood cell adhesion under physiological flow conditions, and allows monitoring of short-range surface processes in whole blood. © 2007 Elsevier B.V. All rights reserved.

  • 28.
    Hansson, Kenny M.
    et al.
    Linköping University, Department of Biomedicine and Surgery, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Tengvall, Pentti
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Lundström, Ingemar
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Rånby, Mats
    Linköping University, Department of Biomedicine and Surgery, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Lindahl, Tomas L.
    Linköping University, Department of Biomedicine and Surgery, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Surface plasmon resonance and free oscillation rheometry in combination: A new approach forstudies on haemostasis and biomaterialsManuscript (preprint) (Other academic)
    Abstract [en]

    In haemostasis and biomaterial research it is important to be able to study biological processes at surfaces and in the bulk. Surface plasmon resonance (SPR) is sensitive to changes at surface and free oscillation rheometry (FOR) probes the bulk. The present work demonstrates the usefulness of the combination of the techniques for simultaneous real-time measurements on coagulation and fibrinolysis of blood plasma, as well as coagulation of whole blood. SFLLRN stimulated coagulation of native whole blood presented a higher SPR signal with a different appearance than for plasma coagulation, while the FOR signals corresponding to plasma and whole blood coagulation were similar. This result indicated that the SPR technique was more sensitive to cell-surface interactions than to fibrin formation in whole blood, while the FOR technique were equally sensitive to coagulation in whole blood and plasma. Spontaneous coagulation of native whole blood in contact with methyland hydroxyl-terminated self-assembled monolayers on gold and gold surfaces regenerated after coagulation by degradation of adsorbed proteins with trypsin and SOS were also studied. The regenerated gold surfaces displayed the shortest coagulation times, although the contact-activation of blood coagulation was found to be low. The methylated and hydroxylated surfaces were comparable in terms of coagulation activation, while the hydroxylated surfaces presented FOR signals that indicated difficulties for the coagulum to attach to the surface. The combination of SPR and FOR may be suited for studies of cell-surface interactions, and may find applications in studies of blood cell defects in patients and testing of medical substances.

  • 29.
    Hansson, Kenny
    et al.
    Linköping University, Department of Biomedicine and Surgery, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Tengvall, Pentti
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Lundström, Ingemar
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Rånby, Mats
    Linköping University, Department of Biomedicine and Surgery, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Lindahl, Tomas
    Linköping University, Department of Biomedicine and Surgery, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Comparative studies with surface plasmon resonance and free oscillation rheometry on the inhibition of platelets with cytochalasin E and monoclonal antibodies towards GPIIb/IIIa2002In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 17, no 9, p. 761-771Article in journal (Refereed)
    Abstract [en]

    In the haemostatic system a multitude of processes are intertwined in fine-tuned interactions that arrest bleeding, keep the circulatory system open, and the blood flowing. The occurrence of both surface and bulk interactions adds an additional dimension of complexity. These insights have led to the belief that global overall procedures can inform on the likely behaviour of the system in health and disease. Two sensing procedures: surface plasmon resonance (SPR), which senses surface interactions, and free oscillation rheometry (FOR), which senses interactions within the bulk, have been combined and evaluated. The contribution of blood cells, mainly platelets, to the SPR and FOR signals was explored by simultaneous SPR and FOR measurement during native whole blood coagulation, accelerated via the platelets through addition of SFLLRN peptide and inhibition of platelet aggregation with abciximab (ReoPro®) and of shape change with cytochalasin E. The SPR technique was found to be sensitive to inhibition of blood cell functions such as adhesion to and spreading on surfaces, as well as platelet aggregation. SPR seemed not to be directly sensitive to fibrin polymerisation in coagulating whole blood. The FOR technique detected the coagulation as a bulk phenomenon, i.e. the gelation of the blood due to fibrin formation was detected. The combination of SPR and FOR may therefore be suitable for studies on blood cell functions during coagulation.

  • 30.
    Hansson, Kenny
    et al.
    Linköping University, Department of Biomedicine and Surgery, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Tengvall, Pentti
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Lundström, Ingemar
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Rånby, Mats
    Linköping University, Department of Biomedicine and Surgery, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Lindahl, Tomas
    Linköping University, Department of Biomedicine and Surgery, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Surface plasmon resonance and free oscillation rheometry in combination: a useful approach for studies on haemostasis and interactions between whole blood and artificial surfaces2002In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 17, no 9, p. 747-759Article in journal (Refereed)
    Abstract [en]

    In haemostatic and biomaterial research biological processes at surfaces and in the bulk phase of the surface-contacting medium are important. The present work demonstrates the usefulness of the combination of surface plasmon resonance (SPR), sensitive to changes in refractive index at surfaces, and free oscillation rheometry (FOR), sensitive to rheological properties of the bulk, for simultaneous real-time measurements on coagulation and fibrinolysis of blood plasma and coagulation of whole blood. SFLLRN stimulated coagulation of native whole blood presented a higher SPR signal with different appearance than plasma coagulation, while the FOR signals corresponding to plasma and whole blood coagulation were similar. This indicated that the SPR technique was more sensitive to cell-surface interactions than to fibrin formation in whole blood during coagulation, while the FOR technique were equally sensitive to coagulation in whole blood and plasma. Spontaneous coagulation of native whole blood in contact with methyl- and hydroxyl-terminated self-assembled monolayers (SAM) on gold and gold surfaces regenerated after coagulation were also studied. The regenerated gold surfaces displayed the shortest coagulation times, although the contact-activation of blood coagulation for these surfaces was low. The methylated and hydroxylated surfaces were comparable in terms of coagulation activation, while the hydroxylated surfaces presented FOR signals that indicated detaching of the coagulum from the surface. The combination of SPR and FOR is well suited for studies of cell– and protein–surface interactions and simultaneous bulk processes. Possible applications are investigations of blood cell defects in patients and monitoring of native whole blood interactions with artificial surfaces.

  • 31.
    Hansson, Kenny
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Tosatti, Samuele
    Isaksson, Joakim
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    Wetterö, Jonas
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Molecular and Clinical Medicine, Medical Microbiology.
    Textor, Marcus
    Lindahl, Tomas
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Division of clinical chemistry. Östergötlands Läns Landsting, Centre for Laboratory Medicine, Department of Clinical Chemistry.
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics.
    Whole blood coagulation on protein adsorption-resistant PEG and peptide functionalised PEG-coated titanium surfaces2005In: Biomaterials, ISSN 0142-9612, E-ISSN 1878-5905, Vol. 26, no 8, p. 861-872Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to investigate whole blood coagulation on low blood plasma protein adsorbing surfaces. For this purpose, the polycationic graft copolymer poly(L-lysine)-g-poly(ethylene glycol) (PLL-g-PEG), PLL-g-PEG grafted with a cell adhesive peptide containing the amino acid sequence -Arg-Gly-Asp- (RGD), and PLL-g-PEG with a control peptide -Arg-Asp-Gly- (RDG) were adsorbed onto titanium (oxide), forming stable monomolecular adlayers through electrostatic attraction. Free oscillation rheometry and complementary techniques were used to measure the coagulation time (CT) and other interactions of the surfaces with native whole blood, recalcified platelet-rich plasma (PRP), and recalcified citrated platelet-free plasma (PFP). The results show that the uncoated titanium surfaces (reference) activated platelets and quickly triggered the coagulation cascade via the intrinsic pathway, whereas the PLL-g-PEG surfaces displayed a prolonged CT, approximately 2-3 times longer compared to uncoated titanium. We hypothesise that blood coagulates outside the vascular system independent of low protein adsorption to or activation by surfaces, due to the absence of an active down-regulation of procoagulative processes by the vascular endothelium.

  • 32.
    Hansson, Kenny
    et al.
    Linköping University, Department of Biomedicine and Surgery, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Vikinge, T. P.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, Faculty of Health Sciences.
    Rånby, M.
    Linköping University, Department of Biomedicine and Surgery, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Tengvall, Pentti
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Lundström, Ingemar
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Johansen, Knut
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, Faculty of Health Sciences.
    Lindahl, Tomas
    Linköping University, Department of Biomedicine and Surgery, Clinical Chemistry. Linköping University, Faculty of Health Sciences.
    Surface plasmon resonance (SPR) analysis of coagulation in whole blood with application in prothrombin time assay1999In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 14, no 8-9, p. 671-682Article in journal (Refereed)
    Abstract [en]

    It is previously shown that surface plasmon resonance (SPR) can be used to study blood plasma coagulation. This work explores the use of this technique for the analysis of tissue factor induced coagulation, i.e. prothrombin time (PT) analysis, of whole blood and plasma. The reference method was nephelometry. The prothrombin time analysis by SPR was performed by mixing two volumes of blood/plasma, one volume of thromboplastin, and one volume of CaCl2 solution directly on a sensor surface. The measurements show good agreement between nephelometry and SPR plasma analysis and also between SPR plasma and whole blood analysis. The effect of anticoagulant treatment on the clotting times was significant both quantitatively and qualitatively. The impact on the SPR signal of different physiological events in the coagulation process is discussed, and tentative interpretations of the sensorgram features are given. The major advantage of the SPR method compared to nephelometry is the possibility to perform analysis on whole blood instead of plasma. In conclusion, SPR is a promising method for whole blood coagulation analysis.

  • 33. Hansson, KM
    et al.
    Vikinge, TP
    Linkoping Univ Hosp, Dept Clin Chem, S-58185 Linkoping, Sweden Linkoping Univ, Forum Scientum Grad Sch, Linkoping, Sweden.
    Ranby, M
    Linkoping Univ Hosp, Dept Clin Chem, S-58185 Linkoping, Sweden Linkoping Univ, Forum Scientum Grad Sch, Linkoping, Sweden.
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Lundström, Ingemar
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Lindahl, Tomas
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry. Linköping University, Department of Clinical and Experimental Medicine, Clinical Chemistry.
    Surface plasmon resonance (SPR) analysis of coagulation in whole blood with application in prothrombin time assay1999In: Thrombosis and Haemostasis, ISSN 0340-6245, p. 917-Conference paper (Other academic)
  • 34.
    Hook, F.F
    et al.
    Department of Applied Physics, Chalmers Institute of Technology, SE-412 96 Göteborg, Sweden.
    Voros, J.
    Vörös, J., Laboratory for Surface Science and Technology, Department of Materials, Swiss Federal Institute of Technology, CH-8092 Zürich, Switzerland.
    Rodahl, M.
    Department of Applied Physics, Chalmers Institute of Technology, SE-412 96 Göteborg, Sweden.
    Kurrat, R.
    Laboratory for Surface Science and Technology, Department of Materials, Swiss Federal Institute of Technology, CH-8092 Zürich, Switzerland.
    Boni, P.
    Böni, P., Paul Scherrer Institut, CH-5232 Villigen PSI, Switzerland.
    Ramsden, J.J.
    Department of Biophysical Chemistry, Biocenter of the University, CH-4056 Basel, Switzerland.
    Textor, M.
    Laboratory for Surface Science and Technology, Department of Materials, Swiss Federal Institute of Technology, CH-8092 Zürich, Switzerland.
    Spencer, N.D.
    Laboratory for Surface Science and Technology, Department of Materials, Swiss Federal Institute of Technology, CH-8092 Zürich, Switzerland.
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Gold, J.
    Department of Applied Physics, Chalmers Institute of Technology, SE-412 96 Göteborg, Sweden.
    Kasemo, B.
    Department of Applied Physics, Chalmers Institute of Technology, SE-412 96 Göteborg, Sweden.
    A comparative study of protein adsorption on titanium oxide surfaces using in situ ellipsometry, optical waveguide lightmode spectroscopy, and quartz crystal microbalance/dissipation2002In: Colloids and Surfaces B: Biointerfaces, ISSN 0927-7765, E-ISSN 1873-4367, Vol. 24, no 2, p. 155-170Article in journal (Refereed)
    Abstract [en]

    The adsorption kinetics of three model proteins - human serum albumin, fibrinogen and hemoglobin - has been measured and compared using three different experimental techniques: optical waveguide lightmode spectroscopy (OWLS), ellipsometry (ELM) and quartz crystal microbalance (QCM-D). The studies were complemented by also monitoring the corresponding antibody interactions with the pre-adsorbed protein layer. All measurements were performed with identically prepared titanium oxide coated substrates. All three techniques are suitable to follow in-situ kinetics of protein-surface and protein-antibody interactions, and provide quantitative values of the adsorbed adlayer mass. The results have, however, different physical contents. The optical techniques OWLS and ELM provide in most cases consistent and comparable results, which can be straightforwardly converted to adsorbed protein molar ('dry') mass. QCM-D, on the other hand, produces measured values that are generally higher in terms of mass. This, in turn, provides valuable, complementary information in two respects: (i) the mass calculated from the resonance frequency shift includes both protein mass and water that binds or hydrodynamically couples to the protein adlayer, and (ii) analysis of the energy dissipation in the adlayer and its magnitude in relation to the frequency shift (c.f. adsorbed mass) provides insight about the mechanical/structural properties such as viscoelasticity. © 2002 Elsevier Science B.V. All rights reserved.

  • 35. Jansson, E
    et al.
    Kalltorp, M
    Linkoping Univ, Dept Phys & Measurement Technol, Appl Phys Lab, SE-58183 Linkoping, Sweden Univ Gothenburg, Inst Anat & Cell Biol, SE-40530 Gothenburg, Sweden.
    Johansson, A
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Thomsen, P
    Linkoping Univ, Dept Phys & Measurement Technol, Appl Phys Lab, SE-58183 Linkoping, Sweden Univ Gothenburg, Inst Anat & Cell Biol, SE-40530 Gothenburg, Sweden.
    On the formation of fibrous capsule and fluid space around machined and porous blood plasma clot coated titanium2001In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 12, no 10-12, p. 1019-1024Article in journal (Refereed)
    Abstract [en]

    Machined and machined submicron porous titanium, with and without a thin blood plasma coating (100 nm), were implanted for 7 or 28 days in subcutaneous pockets on the back of the rat. After explantation the specimens were analyzed by light microscopy with respect to thickness of the fibrous capsule, the fluid space width between implants and fibrous capsule, and formation of blood vessels. The results at 7 days indicate a thinnest fluid space for the plasma clot coated porous titanium surface, and the spaces vanished at the light microscopic level after 28 days outside all the analyzed surfaces. The thickness of the fibrous capsule increased outside the different surfaces at 7-28 days, and in this respect no significant differences were observed between the different surfaces at any time. Analysis of neovascularization showed that the number of vessels and proportion of vessels in the fibrous capsule increased with time at all surfaces, except machined Ti where the number instead decreased from 7 to 28 days. The average distance between the blood vessels and the fluid space increased with time for all types of surfaces. The results in the present study indicate that the healing process around titanium can be modulated by porosity and thin pre-prepared plasma coatings. (C) Kluwer Academic Publishers.

  • 36. Jansson, E.
    et al.
    Kalltorp, M.
    Källtorp, M., Institute of Anatomy and Cell Biology, Göteborg University, Box 420, SE-405 30 Göteborg, Sweden.
    Thomsen, P.
    Institute of Anatomy and Cell Biology, Göteborg University, Box 420, SE-405 30 Göteborg, Sweden.
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Ex vivo PMA-induced respiratory burst and TNF-a secretion elicited from inflammatory cells on machined and porous blood plasma clot-coated titanium2002In: Biomaterials, ISSN 0142-9612, E-ISSN 1878-5905, Vol. 23, no 13, p. 2803-2815Article in journal (Refereed)
    Abstract [en]

    The release of inflammatory mediators around implants and normal wounds may differ due to the presence of the solid surface. In this study, machined and sub-micron porous titanium implants with and without a 100nm thick blood plasma clot were inserted subcutaneously in rat for 3 or 24h. The cell recruitment to the interfaces, in vivo secretion of TNF-a and the ex vivo PMA-induced production of reactive oxygen species were subsequently investigated. The thin plasma clot coating gave rise to an increased ex vivo PMA-stimulated oxygen radical production by implant-associated cells at both implantation times, and an increased cell recruitment at 24h. The total TNF-a secretion was highest at sham sites and plasma clot-coated porous titanium at 24h. After 24h, the cell-type pattern in the exudate around the porous plasma-coated implant was more similar to that found at sham sites than that adjacent to the non-coated implants. No differences were observed between the machined Ti and the machined sub-micron porous Ti. © 2002 Elsevier Science Ltd. All rights reserved.

  • 37.
    Jansson, Eva
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Adsorption of albumin and IgG to porous and smooth titanium2004In: Colloids and Surfaces B: Biointerfaces, ISSN 0927-7765, E-ISSN 1873-4367, Vol. 35, no 1, p. 45-51Article in journal (Refereed)
    Abstract [en]

    The possibility to load submicrometer porous titanium surfaces with relatively small proteins, albumin and immunoglobulin G (IgG) was investigated. The loading ability is of interest due to the possibility of slow release of molecules from biomaterial surfaces, and may be important for the manipulation of wound healing around prostheses. Iodine-125 (125I) labeled albumin and IgG were adsorbed onto smooth and to porous titanium with a pore diameter of 200-300 nm. The smooth and porous surfaces were divided into three groups: hydrophilic, hydrophobic, or to amine-terminated silane (3- aminopropyltriethoxysilane) that bound proteins via glutaraldehyde. The protein solution pH and protein concentrations were varied, and the adsorption experiments made without or in the presence of calcium and magnesium ions. The adsorbed amounts were quantified with a gamma counter. Two to eleven times more proteins adsorbed onto porous than smooth surfaces and the adsorbed amounts increased with increasing protein concentration (0.1-10 mg/ml) during a constant incubation time. The elutability by sodium dodecyl sulphate (SDS) was incomplete on porous surfaces. © 2004 Elsevier B.V. All rights reserved.

  • 38.
    Jansson, Eva
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    In vitro preparation and ellipsometric characterization of thin blood plasma clot films on silicon2001In: Biomaterials, ISSN 0142-9612, E-ISSN 1878-5905, Vol. 22, no 13, p. 1803-1808Article in journal (Refereed)
    Abstract [en]

    The wound-healing process around implants differs from that of a normal healing without the inserted material. In this work, the composition of a natural wound surface was mimicked through clotting of a thin human blood plasma film with approximate ellipsometric thickness of 100nm onto differently pretreated silicon surfaces. Their stability was investigated by incubations in sodium dodecyl sulphate (SDS) solutions. The enzymatic clot degradation was induced through addition of human tissue plasminogen activator (t-PA) to the plasma and the surface protein remnants after the degradation were analyzed with polyclonal antibodies. The results show that the plasma films were not SDS resistant on hydrophilic silicon. However, stability was obtained after preparation on hydrophobic silicon or when albumin or fibrinogen was immobilized to silicon before the plasma incubations. Different surfaces bound different polyclonal antibodies after the clot film degradation. The methods indicate a simple means to improve or reestablish a normal tissue inflammatory response around biomaterials. Copyright © 2001 Elsevier Science Ltd.

  • 39. Kalltorp, M
    et al.
    Carlen, A
    Thomsen, P
    Olsson, J
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Analysis of rat plasma proteins desorbed from gold and methyl- and hydroxyl-terminated alkane thiols on gold surfaces2000In: Journal of materials science. Materials in medicine, ISSN 0957-4530, E-ISSN 1573-4838, Vol. 11, no 3, p. 191-199Article in journal (Refereed)
    Abstract [en]

    It is believed that adsorbed blood or plasma components, such as water, peptides, carbohydrates and proteins, determine key events in the concomitant inflammatory tissue response close to implants. The aim of the present study was to develop a procedure for the collection and analysis of minor amounts of proteins bound to solid metal implant surfaces. The combination of a sodium dodecyl sulfate washing method coupled with a polyacylamide gel electrophoretic protein separation technique (SDS-PAGE), Western blot and image analysis enabled the desorption, identification and semiquantification of specific proteins. The analyzed proteins were albumin, immunoglobulin G, fibrinogen and fibronectin. Concentration procedures of proteins were not required with this method despite the small area of the test surfaces. The plasma proteins were adsorbed to pure gold and hydroxylated and methylated gold surfaces, which elicit different tissue responses in vivo and plasma protein adsorption patterns in vitro. The image analysis revealed that the pure gold surfaces adsorbed the largest amount of total and specific proteins. This is in accordance with previous ellipsometry/antibody experiments in vitro. Further, the principles described for the protein analysis can be applied on implant surfaces ex vivo. (C) 2000 Kluwer Academic Publishers.

  • 40.
    Karlsson, L M
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics.
    Lundström, Ingemar
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics.
    Arwin, Hans
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Optics .
    Adsorption of human serum albumin in porous silicon gradients2003Conference paper (Other academic)
    Abstract [en]

    Backside etching has been utilized to produce gradients of pore size and layer thickness in porous silicon. Human serum albumin (HSA) was adsorbed on such gradients at two different pH values: 4.9, the pI of HSA, and 7.4, the physiological pH. The samples were investigated by scanning electron microscopy, spectroscopic ellipsometry, and autoradiography. The results show that the protein adsorbed displays a gradient along with the pore size and the thickness gradient. The higher than current density used during etching, the more sway-back shaped curves were seen for the protein adsorption pattern, independent of pH. When 50 mA/cm2 current density was used during etching, the quota between the maximal intensity value and the plateau value seen after adsorption of the HSA increased for pH 7.4.

  • 41.
    Karlsson, L M
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics.
    Lundström, Ingemar
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics.
    Arwin, Hans
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Optics .
    Back-side etching A tool for making morphology gradients in porous silicon2002In: Journal of the Electrochemical Society, ISSN 0013-4651, E-ISSN 1945-7111, Vol. 149, no 12Article in journal (Refereed)
    Abstract [en]

    A new method for preparing morphology gradients in electrochemically etched porous silicon layers in presented. The idea is to etch on the back side of the anode and thus utilize and inhomogenous electric field to control the pore size along a surface. The etching procedure resulted in a complex gradient in pore size, porosity, and porous layer thickness, which was studied by spectroscopic ellipsometry and scanning electron microscopy. The gradients are of interest, e.g., for biomaterials research, bio-sensor applications, and for basic studies of adsorption of organic molecules, like proteins. In order to investigate the potential of the gradient surfaces for protein adsorption studies, these were exposed to human serum albumin, and a gradient in the amount of adsorbed protein was observed.

  • 42.
    Karlsson, L M
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology.
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics.
    Lundström, Ingemar
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics.
    Arwin, Hans
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Optics .
    Penetration and loading of human serum albumin in porous silicon layers with different pore sizes and thicknesses2003In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 266, no 1, p. 40-47Article in journal (Refereed)
    Abstract [en]

    Human serum albumin was adsorbed into porous silicon layers with thickness up to 3 µm and with different mean pore radius in the range 4.5-10 nm. The adsorbed amount of protein was quantified by I125 radioactive labeling techniques and ellipsometry. The results show that albumin penetrated into the pores when the mean pore radius was larger than 5.5 nm, but could not totally occupy the available surface area when the layer thickness was larger than 1 µm. Loading of albumin both into porous layers and onto plane silicon as a function of albumin concentration was also investigated. These measurements show that loading of protein increased with protein concentration at least up to 10 mg/ml for porous silicon and up to 1 mg/ml for plane silicon. The maximum deposition into the type of porous layers used here was 28 µg/cm2, compared to 0.36 µg/cm2 for plane silicon. © 2003 Elsevier Inc. All rights reserved.

  • 43.
    Larsson, Jenny
    et al.
    Linköping University, Department of Neuroscience and Locomotion, Pathology. Linköping University, Faculty of Health Sciences.
    Persson, Carina
    Linköping University, Department of Neuroscience and Locomotion, Pathology. Linköping University, Faculty of Health Sciences.
    Tengvall, Pentti
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Lundqvist Gustafsson, Helen
    Linköping University, Department of Neuroscience and Locomotion, Pathology. Linköping University, Faculty of Health Sciences.
    Anti-inflammatory effects of a titanium-peroxy gel: role of oxygen metabolites and apoptosis2004In: Journal of Biomedical Materials Research, ISSN 0021-9304, E-ISSN 1097-4636, Vol. 68, no 3, p. 448-457Article in journal (Refereed)
    Abstract [en]

    Polymorphonuclear neutrophils (PMN) are among the first inflammatory cells to arrive at an implant interface, where they encounter with the foreign material and may produce reactive oxygen species (ROS). During the interaction between titanium and ROS, titanium-peroxy (Ti-peroxy) compounds may be formed. We used a Ti-peroxy gel, made from titanium and hydrogen peroxide, to study the effects of Ti-peroxy compounds on PMN. In the absence of serum, the Ti-peroxy gel decreased the oxidative response of PMN to yeast and PMA and reduced PMN apoptosis without inducing necrosis. These effects could not be ascribed to the release of hydrogen peroxide from the Ti-peroxy gel, because a steady-state hydrogen peroxide producing system failed to mimic the effects of the gel. The effects were similarly unaffected when PMN were preincubated with β2-integrin antibodies, questioning the involvement of adhesion molecules. Nevertheless, when a filter was used to separate the Ti-peroxy gel from the cells, the gel effect on PMN life span was abolished, pointing to a contact-dependent mechanism. In the presence of serum, the Ti-peroxy gel had no effect on the PMN oxidative response and life span, but appeared rather inert. In summary, this study demonstrates that the Ti-peroxy gel has potentially anti-inflammatory properties through a combined peroxide and physical contact effect, supporting the notion that interactions between titanium and inflammatory cells are responsible for the good performance of titanium in vivo.

  • 44.
    Lestelius, Magnus
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Engquist, Isak
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Tengvall, Pentti
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Chaudhury, M. K.
    Lehigh university, USA.
    Liedberg, Bo
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, The Institute of Technology.
    Order/disorder gradients of n-alkanethiols on gold1999In: Colloids and Surfaces B: Biointerfaces, ISSN 0927-7765, E-ISSN 1873-4367, Vol. 15, no 1, p. 57-70Article in journal (Refereed)
    Abstract [en]

    This paper explores the interfacial properties of one-dimensional molecular gradients of alkanethiols (HS-(CH2)(n)- X) on gold. The kinetics and thermodynamics of monolayer formation are important issues for these types of mixed molecular assemblies. The influence of chain length difference on the contact angles with hexadecane (HD), theta(a) and theta(r), and the hysteresis, has been studied by employing alkanethiols HS-(CH2)(n)-CH3, with n = 9, 11, 13, 15 and 17, in the preparation of the self-assembled monolayers (SAM) gradients. The contact angles with hexadecane, at the very extreme ends of the gradients, show characteristic values of a highly ordered CH3-like assembly: theta(a) = 45-50 degrees. In the middle of the gradients theta(a) drops noticeably and exhibits values representative for CH2-like polymethylenes, theta(a) = 20-30 degrees, indicating a substantial disordering of the protruding chains of the longer component in the gradient assembly. As expected, the exposure of CH2-groups to the probing liquid increases with increasing differential chain length of the two n-alkanethiol used, in this case eight methylene units. However, the contact angles always display a non-zero value which means that even at a chain length difference of eight methylene units there is a substantial exposure of methyl (CH3) groups to the probing liquid. With infrared reflection-absorption spectroscopy (IRAS) we have monitored the structural behavior of the polymethylene chains along the gradient. We find complementary evidence for disordered chains in the gradient region, and the IRAS results correlate well with the contact angle measurements. (C) 1999 Elsevier Science B.V. All rights reserved.

  • 45.
    Linderbäck, Paula
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Agholme, Fredrik
    Linköping University, Department of Clinical and Experimental Medicine, Orthopaedics and Sports Medicine. Linköping University, Faculty of Health Sciences.
    Wermelin, Karin
    Linköping University, Department of Clinical and Experimental Medicine, Orthopaedics and Sports Medicine. Linköping University, Faculty of Health Sciences.
    Närhi, Timo
    Turku Clinical Biomaterial Centre, The University of Turku, FI-20520 Turku, Finland.
    Tengvall, Pentti
    University of Gothenburg.
    Aspenberg, Per
    Linköping University, Department of Clinical and Experimental Medicine, Orthopaedics and Sports Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Centre for Surgery, Orthopaedics and Cancer Treatment, Department of Orthopaedics in Linköping.
    Weak effect of strontium on early implant fixation in rat tibia2012In: Bone, ISSN 8756-3282, E-ISSN 1873-2763, Vol. 50, no 1, p. 350-356Article in journal (Refereed)
    Abstract [en]

    Strontium ranelate increases bone mass and is used in the treatment of osteoporosis. Its effects in metaphyseal bone repair are largely unknown. We inserted a stainless steel and a PMMA screw into each tibia of male Sprague-Dawley rats. The animals were fed with ordinary feed (n =40) or with addition of strontium ranelate (800mg/kg/day; n = 20). As a positive control, half of the animals on control feed received alendronate subcutaneously. The pullout force of the stainless steel screws was measured after 4 and 8 weeks, and μCT was used to assess bone formation around the PMMA screws. No significant effects of strontium treatment on pullout force were observed, but animals treated with bisphosphonate showed a doubled pullout force. Strontium improved the microarchitecture of the cancellous bone below the primary spongiosa at the growth plate, but no significant effects were found around the implants. Strontium is known to improve bone density, but it appears that this effect is weak in conjunction with metaphyseal bone repair and early implant fixation.

  • 46.
    Linderbäck, Paula
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Areva, Sami
    University of Turku.
    Aspenberg, Per
    Linköping University, Department of Clinical and Experimental Medicine, Orthopaedics and Sports Medicine. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Orthopaedic Centre, Department of Orthopaedics Linköping.
    Tengvall, Pentti
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics . Linköping University, The Institute of Technology.
    Sol-gel derived titania coating with immobilized bisphosphonate enhances screw fixation in rat tibia2010In: JOURNAL OF BIOMEDICAL MATERIALS RESEARCH PART A, ISSN 1549-3296, Vol. 94A, no 2, p. 389-395Article in journal (Refereed)
    Abstract [en]

    A variety of surface modifications have been tested for the enhancement of screw fixation in bone, and locally delivered anti-osteoporosis drugs such as bisphosphonates (BP) are then of interest. In this in vivo study, the impact of surface immobilized BP was compared with systemic BP delivery and screws with no BP. After due in vitro characterization, differently treated stainless steel (SS) screws were divided into four groups with 10 rats each. Three of the groups received screws coated with sol gel derived TiO2 and calcium phosphate (SS+TiO2+CaP). One of these had no further treatment, one had alendronate (BP) adsorbed to calcium phosphate mineral, and one received systemic BP treatment. The fourth group received uncoated SS screws and no BP (control). The screw pullout force was measured after 4 weeks of implantation in rat tibiae. The immobilized amount and release rate of alendronate could be controlled by different immersion times. The SS+TiO2+CaP coating did not increase the pullout force compared to SS alone. Surface delivered alendronate enhanced the pullout force by 93% [p = 0.000; 95% Confidence Interval (CI): 67-118%] compared to SS, and by 39% (p = 0.044; 95% CI: 7-71%) compared to systemic alendronate delivery. Both surface immobilized and systemically delivered alendronate improved implant fixation. Also, locally delivered, that is, surface immobilized alendronate showed a better fixation than systemically delivered. Using sot gel derived TiO2 as a platform, it is possible to administer controllable amounts of a variety of BPs.

  • 47.
    Linderbäck, Paula
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Areva, Sami
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Pamidronate release kinetics of SBF immersed TiO2 sol-gel coatings2007In: 21st European Conference on Biomaterials,2007, 2007Conference paper (Other academic)
    Abstract [en]

        

  • 48.
    Linderbäck, Paula
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Ericsson, Emma
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics .
    Alendronate release and binding at CaP interfaces2007In: ScanBalt Biomaterials Days,2007, 2007Conference paper (Other academic)
  • 49.
    Lundström, Ingemar
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics.
    Tengvall, Pentti
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Applied Physics.
    Surface Properties and Osseointegration2005In: The Osseointegration Book from Calvarium to Calcaneus / [ed] Per-Ingvar Brånemark, Berlin: Quintessenz VerlagsGmbH , 2005, 1, p. 133-141Chapter in book (Other academic)
    Abstract [en]

      Branemark Osseointegration Center, Goteborg, Sweden. Comprehensive reference brings together the background and history of the subject and covers osseointegration from its origins, through theory to practice. Presents a wealth of data about the current applications and covers its origins in dentistry to facial reconstruction and orthopedics. High-quality color images

  • 50.
    Pasternak, Björn
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Orthopaedics and Sports Medicine . Linköping University, Faculty of Health Sciences.
    Missios, Anna
    Askendal, Agneta
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, The Institute of Technology.
    Tengvall, Pentti
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics . Linköping University, The Institute of Technology.
    Aspenberg, Per
    Linköping University, Department of Clinical and Experimental Medicine, Orthopaedics and Sports Medicine . Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Orthopaedic Centre, Department of Orthopaedics Linköping.
    Doxycycline-coated sutures improve the suture-holding capacity of the rat Achilles tendon2007In: Acta Orthopaedica, ISSN 1745-3674, Vol. 78, no 5, p. 680-686Article in journal (Refereed)
    Abstract [en]

    There is evidence of high matrix metalloproteinase (MMP) activity around sutures inserted into tendons. This probably results in tissue breakdown, allowing the suture to cut through the tendon, and thus contributes to repair-site elongation and gap formation. We therefore hypothesized that treatment with the MMP inhibitor doxycycline would improve the sutureholding capacity of tendon. Animals, methods and results In the first sub-study, rats received a suture in the Achilles tendon. One group was treated with systemic doxycycline and the other received no treatment. At 3, 5, and 7 days, suture-holding capacity was measured mechanically. The pull-out force and energy were reduced in all tendons, at 3 days compared to freshly inserted sutures, but no further reduction was detected at later time points. Doxycycline- treated tendons showed improved suture-holding capacity as measured by higher energy uptake than in untreated tendons. Force at failure showed a trend towards improvement. The effect was most evident on day 3. In the second sub-study, sutures were coated with doxycycline. At 3 days, local doxycycline treatment caused improved suture-holding capacity—as measured by higher force at failure and higher energy uptake.

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