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  • 51.
    Chey, Chan Oeurn
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Patra, Hirak K
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biosensorer och bioelektronik. Linköpings universitet, Tekniska högskolan.
    Tengdelius, Mattias
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska högskolan.
    Golabi, Mohsen
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biosensorer och bioelektronik. Linköpings universitet, Tekniska högskolan.
    Parlak, Onur
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biosensorer och bioelektronik. Linköpings universitet, Tekniska högskolan.
    Imani, Roghayeh
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biosensorer och bioelektronik. Linköpings universitet, Tekniska högskolan.
    Elhag, Sami A. I.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Fysik och elektroteknik. Linköpings universitet, Tekniska högskolan.
    Yandi, Wetra
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Tiwari, Ashutosh
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biosensorer och bioelektronik. Linköpings universitet, Tekniska högskolan.
    Impact of nanotoxicology towards technologists to end users2013Ingår i: Advanced Materials Letters, ISSN 0976-3961, E-ISSN 0976-397X, Vol. 4, nr 8, s. 591-597Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The length scale for nanomaterial is small enough to be invisible and presume innocence for the initial avoidance of the toxicity issues. Again it was beyond the understanding of the time frame when nanotechnology just blooms that a length scale itself might be an important toxic parameter apart from its materialistic properties. We present this report to address the fundamental issues and questions related to the nanotoxicity issues from laboratory to the land of applications. We emphasize about the basic nanoscale materials that are regularly being used by the scientific community and the nanotechnology based materials that has already in the market or will come soon.

  • 52.
    Dahlstedt, E.
    et al.
    Dept. of Chem., Organic Chemistry, Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
    Hellberg, J.
    Dept. of Chem., Organic Chemistry, Royal Institute of Technology, SE-100 44 Stockholm, Sweden.
    Petoral, Rodrigo Jr
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Uvdal, Kajsa
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Synthesis of tetrathiafulvalenes suitable for self-assembly applications2004Ingår i: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 14, nr 1, s. 81-85Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A series of new tetrathiafulvalenes, with double alkylthiol or alkyldisulfide substitution, have been prepared with a synthetic procedure that allows variation of different substituents. The target compounds 6a-e and 15e-i are sparsely soluble in organic solvents, but TTFs 6d and 15g gave a relatively dense packed monolayer upon exposure to gold surfaces.

  • 53. Demers, LM
    et al.
    Östblom, Mattias
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Zhang, Hanmin
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Jang, NH
    Liedberg, Bo
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Mirkin, CA
    Thermal desorption behavior and binding properties of DNA bases and nucleosides on gold2002Ingår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 124, nr 38, s. 11248-11249Artikel i tidskrift (Refereegranskat)
  • 54. Dunér, G
    et al.
    Andersson, H
    Myrskog, Annica
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Hedlund, M
    Aastrup, T
    Ramstrom, o
    Surface-confined photopolymerization of pH-responsive acrylamide/acrylate brushes on polymer thin films2008Ingår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 24, nr 14, s. 7559-7564Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Dynamic acrylamide/acrylate polymeric brushes were synthesized at gold-plated quartz crystal surfaces. The crystals were initially coated with polystyrene-type thin films, derivatized with photolabile iniferter groups, and subsequently subjected to photoinitiated polymerization in acrylamide/acrylate monomer feeds. This surface-confined polymerization method enabled direct photocontrol over the polymerization, as followed by increased frequency responses of the crystal oscillations in a quartz crystal microbalance (QCM). The produced polymer layers were also found to be highly sensitive to external acid/base stimuli. Large oscillation frequency shifts were detected when the brushes were exposed to buffer solutions of different pH. The dynamic behavior of the resulting polymeric brushes was evaluated, and the extent of expansion and contraction of the films was monitored by the QCM setup in situ in real time. The resulting responses were rapid, and the effects were fully reversible. Low pH resulted in full contractions of the films, whereas higher pH yielded maximal expansion in order to minimize repulsion around the charged acrylate centers. The surfaces also proved to be very robust because the responsiveness was reproducible over many cycles of repeated expansion and contraction. Using ellipsometry, copolymer layers were estimated to be ∼220 nm in a collapsed state and ∼340 nm in the expanded state, effectively increasing the thickness of the film by 55%. © 2008 American Chemical Society.

  • 55.
    Ederth, T.
    et al.
    Department of Chemistry, Surface Chemistry, Royal Institute of Technology, SE-100 44 Stokholm, Sweden, Institute for Surface Chemistry, Box 5607, SE-114 86 Stockholm, Sweden, Phys. and Theor. Chem. Laboratory, South Parks Road, Oxford OX1 3Q2, United Kingdom.
    Liedberg, Bo
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Influence of wetting properties on the long-range `hydrophobic' interaction between self-assembled alkylthiolate monolayers2000Ingår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 16, nr 5, s. 2177-2184Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The effect of solid-liquid interfacial energy on the long-range attraction between self-assembled thiolate monolayers in water has been studied by direct force measurements. The solid-liquid interfacial energy was tuned by changing the properties of the solid surface: the thiolate monolayers were prepared by self-assembly of mixtures of methyl- and hydroxyl-functionalized alkylthiols onto thin gold films. The wetting properties were examined by contact angle measurements with the Wilhelmy plate method. Our results show that the shape of the long-ranged attractive force is sensitive to the advancing solid-liquid contact angle: whenever it exceeds 90° the force profiles are discontinuous and contains steps, whereas no attraction beyond the van der Waals force is observed for contact angles lower than 90°. We attribute the steps in the long-range attraction between hydrophobic surfaces to bridging of microscopic bubbles residing on the surfaces, and we conclude that the stability of these bubbles are related to macroscopic contact angles.

  • 56.
    Ederth, Thomas
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Ekblad, Tobias
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Swelling of grafted poly(ethylene glycol)-containing hydrogels: a neutron re°ectivity studyManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    Hydrogels are used to enhance biocompatibility and reduce inflammation in biomedical applications, and as area-enlarging matrices in bioanalytical devices. For either of these applications, the structure of the hydrogel is important for the function, and thus structural understanding of hydrogels in their wet state is highly relevant for the use and development of these materials. Also, processing of these materials is frequently made in ambient air, and it is of interest to relate the properties of dry, or humid air-swollen hydrogels, to their wet properties.

    We use neutron reflectometry to follow the swelling of hydrogels in air of controlled humidity. Comparing hydrogels prepared on silica and gold substrates { both of relevance to bioanalytical applications { we observe that the swelling is different, reflecting a structural difference between these polymers, but that the water content of the polymer films near saturation is near 33% in both cases. Upon immersion in water, the swelling is estimated to approximately 2 x the dry thickness of the polymer, though a consistent quantitative determination of the polymer profile could not be made. Finally, we observe that the hydrogels are unaffected by either positively and negatively charged proteins.

  • 57.
    Ederth, Thomas
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Liedberg, Bo
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Porous nanoparticle assemblies as permeable supports for lipid bilayer membranes (Poster)2005Övrigt (Övrig (populärvetenskap, debatt, mm))
    Abstract [en]

    Nanoscale Surface Self-Assembly (EuChem Conference, June 19-23, 2005, Sigtuna, Sweden

  • 58.
    Ederth, Thomas
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Nygren, Patrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Ekblad, Tobias
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Östblom, Mattias
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Liedberg, Bo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Pettitt, M.E.
    The University of Birmingham, School of Biosciences, Birmingham, UK.
    Callow, M.E.
    The University of Birmingham, School of Biosciences, Birmingham, UK.
    Callow, J.A.
    The University of Birmingham, School of Biosciences, Birmingham, UK.
    Interactions of algal spores and diatoms with mixed synthetic peptide SAMs2007Konferensbidrag (Övrigt vetenskapligt)
    Ladda ner fulltext (pdf)
    fulltext
  • 59.
    Ederth, Thomas
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Nygren, Patrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Pettitt, M. E.
    University of Birmingham.
    Oumlstblom, M.
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    Du, Chun-Xia
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    Broo, Klas
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    Callow, M. E.
    University of Birmingham.
    Callow, J.
    University of Birmingham.
    Liedberg, Bo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Anomalous settlement behavior of Ulva linza zoospores on cationic oligopeptide surfaces2008Ingår i: Biofouling (Print), ISSN 0892-7014, E-ISSN 1029-2454, Vol. 24, nr 4, s. 303-312Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 60.
    Ederth, Thomas
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Pettitt, M E
    University of Birmingham.
    Nygren, Patrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Du, Chun-Xia
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär fysik. Linköpings universitet, Tekniska fakulteten.
    Ekblad, Tobias
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Zhou, Ye
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Falk, Magnus
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär fysik. Linköpings universitet, Tekniska fakulteten.
    Callow, M E
    University of Birmingham.
    Callow, J A
    University of Birmingham.
    Liedberg, Bo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Interactions of Zoospores of Ulva linza with Arginine-Rich Oligopeptide Monolayers2009Ingår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 25, nr 16, s. 9375-9383Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 61. Beställ onlineKöp publikationen >>
    Ekblad, Tobias
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Hydrogel coatings for biomedical and biofouling applications2010Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Many applications share a substantial and yet unmet need for prediction and control of interactions between surfaces and proteins or living cells. Examples are blood-contacting biomaterials, biosensors, and non-toxic anti-biofouling coatings for ship hulls. The main focus of this thesis work has been the synthesis, characterization and properties of a group of coatings, designed for such applications. Many types of substrates, particularly plastics, were coated directly with ultrathin, hydrophilic polymer coatings, using a newly developed polymerization method initiated by short-wavelength ultraviolet light.

    The thesis contains eight papers and an introduction aimed to provide a context for the research work. The common theme, discussed and analyzed throughout the work, has been the minimization of non-specific binding of proteins to surfaces, thereby limiting the risk of uncontrolled attachment of cells and higher organisms. This has mainly been accomplished through the incorporation of monomer units bearing poly(ethylene glycol) (PEG) side chains in the coatings. Such PEG-containing “protein resistant” coatings have been used in this work as matrices for biosensor applications, as blood-contacting inert surfaces and as antibiofouling coatings for marine applications, with excellent results. The properties of the coatings, and their interactions with proteins and cells, have been thoroughly characterized using an array of techniques such as infrared spectroscopy, ellipsometry, atomic force microscopy, surface plasmon resonance and neutron reflectometry. In addition, other routes to fabricate coatings with high protein resistance have also been utilized. For instance, the versatility of the fabrication method has enabled the design of gradients with varying electrostatic charge, affecting the protein adsorption and leading to protein resistance in areas where the charges are balanced.

    This thesis also describes a novel application of imaging surface plasmon resonance for the investigation of the surface exploration behavior of marine biofouling organisms, in particular barnacle larvae. This technique allows for real-time assessment of the rate of surface exploration and the deposition of protein-based adhesives onto surfaces, a process which was previously very difficult to investigate experimentally. In this thesis, the method was applied to several model surface chemistries, including the hydrogels described above. The new method promises to provide insights into the interactions between biofouling organisms and a surface during the critical stages prior to permanent settlement, hopefully facilitating the development of antibiofouling coatings for marine applications.

    Delarbeten
    1. Photografted poly(ethylene glycol) matrix for affinity interaction studies
    Öppna denna publikation i ny flik eller fönster >>Photografted poly(ethylene glycol) matrix for affinity interaction studies
    2007 (Engelska)Ingår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 8, nr 1, s. 287-295Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    A poly(ethylene glycol) (PEG)-based matrix for studies of affinity interactions is developed and demonstrated. The PEG matrix, less than 0.1 μm thick, is graft copolymerized onto a cycloolefin polymer from a mixture of PEG methacrylates using a free radical reaction initiated by UV light at 254 nm. The grafting process is monitored in real time, and characteristics such as thickness, homogeneity, relative composition, photostability, and performance in terms of protein resistance in complex biofluids and sensor qualities are investigated with null ellipsometry, infrared spectroscopy, and surface plasmon resonance. The matrix is subsequently modified to contain carboxyl groups, thereby making it possible to immobilize ligands in a controlled and functional manner. Human serum albumin and fibrinogen are immobilized and successfully detected by antibody recognition using surface plasmon resonance. The results are encouraging and suggest that the PEG matrix is suitable for biochip and biosensor applications in demanding biofluids.

    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-14606 (URN)10.1021/bm060685g (DOI)
    Tillgänglig från: 2007-10-12 Skapad: 2007-10-12 Senast uppdaterad: 2017-12-13
    2. Poly(ethylene glycol)-Containing Hydrogel Surfaces for Antifouling Applications in Marine and Freshwater Environments
    Öppna denna publikation i ny flik eller fönster >>Poly(ethylene glycol)-Containing Hydrogel Surfaces for Antifouling Applications in Marine and Freshwater Environments
    Visa övriga...
    2008 (Engelska)Ingår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 9, nr 10, s. 2775-2783Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

       

    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-43901 (URN)10.1021/bm800547m (DOI)75058 (Lokalt ID)75058 (Arkivnummer)75058 (OAI)
    Tillgänglig från: 2009-10-10 Skapad: 2009-10-10 Senast uppdaterad: 2017-12-13
    3. Lateral Control of Protein Adsorption on Charged Polymer Gradients
    Öppna denna publikation i ny flik eller fönster >>Lateral Control of Protein Adsorption on Charged Polymer Gradients
    Visa övriga...
    2009 (Engelska)Ingår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 25, nr 6, s. 3755-3762Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    This work describes the fabrication, characterization, and protein adsorption behavior of charged polymer gradients. The thin gradient films were fabricated by a two-step technique using UV-initiated free-radical polymerization in a reactor with a moving shutter. A homogeneous layer of cationic poly(2-aminoethyl methacrylate hydrochloride) was first formed, followed by a layer of oppositely charged poly(2-carboxyethyl acrylate) with a continuously increasing thickness. Adsorption from protein solutions as well as human blood plasma was investigated by imaging surface plasmon resonance and infrared microscopy. The results showed excessive protein adsorption in the areas where one of the polymers dominated the composition, while there was a clear minimum at an intermediate position of the gradient. The charge of the surface was estimated by direct force measurements and found to correlate well with the protein adsorption, showing the lowest net charge in the same area as the protein adsorption minimum. We therefore hypothesize that a combination of the charged polymers, in the right proportions, can result in a protein-resistant surface due to balanced charges.

    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-17501 (URN)10.1021/la803443d (DOI)
    Tillgänglig från: 2009-03-27 Skapad: 2009-03-27 Senast uppdaterad: 2019-04-24
    4. Blood compatibility of photografted hydrogel coatings
    Öppna denna publikation i ny flik eller fönster >>Blood compatibility of photografted hydrogel coatings
    2010 (Engelska)Ingår i: ACTA BIOMATERIALIA, ISSN 1742-7061, Vol. 6, nr 7, s. 2599-2608Artikel i tidskrift (Övrigt vetenskapligt) Published
    Abstract [en]

    In this work we have evaluated the haemocompatibility of different surface modifications, intended for biomaterials and biosensor applications. Polystyrene slides were coated with thin hydrogel films by self-initiated photografting of four different monomers. The hydrogel surface modifications were thoroughly characterized and tested for their protein resistance and ability to facilitate platelet adhesion and activation of the coagulation system. There was very little protein adsorption from human plasma on the hydrogels formed from poly(ethylene glycol) methacrylate (PEGMA) and 2-hydroxyethyl methacrylate (HEMA). Platelet adhesion tests performed under both static and flow conditions showed that these coatings also demonstrated very high resistance towards platelet adhesion. A small amount of platelets were found to adhere to hydrogels formed from ethylene glycol methyl ether methacrylate (EGMEMA) and 2-carboxyethyl methacrylate (CEA). The polystyrene substrates themselves facilitated large amounts of platelet adhesion under both static and flow conditions. Utilizing a novel setup for imaging of coagulation, it was shown that none of the hydrogel surfaces activated the coagulation system to any great extent. We suggest that this simple fabrication method can be used to produce hydrogel coatings with unusually high blood compatibility, suitable for demanding biomaterials applications.

    Ort, förlag, år, upplaga, sidor
    Elsevier Science B.V. Amsterdam, 2010
    Nyckelord
    Hydrogel; Biomaterial; Protein adsorption; Coagulation; Platelet
    Nationell ämneskategori
    Medicin och hälsovetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-19175 (URN)10.1016/j.actbio.2009.12.046 (DOI)000278868000027 ()
    Tillgänglig från: 2009-06-12 Skapad: 2009-06-12 Senast uppdaterad: 2011-03-23Bibliografiskt granskad
    5. Patterned Hydrogels for Controlled Platelet Adhesion from Whole Blood and Plasma
    Öppna denna publikation i ny flik eller fönster >>Patterned Hydrogels for Controlled Platelet Adhesion from Whole Blood and Plasma
    Visa övriga...
    2010 (Engelska)Ingår i: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 20, nr 15, s. 2396-2403Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    This work describes the preparation and properties of hydrogel surface chemistries enabling controlled and well-defined cell adhesion. The hydrogels may be prepared directly on plastic substrates, such as polystyrene slides or dishes, using a quick and experimentally simple photopolymerization process, compatible with photolithographic and microfluidic patterning methods. The intended application for these materials is as substrates for diagnostic cell adhesion assays, particularly for the analysis of human platelet function. The adsorption of fibrinogen and other platelet promoting molecules is shown to be completely inhibited by the hydrogel, provided that the film thickness is sufficient (>5 nm). This allows the hydrogel to be used as a matrix for presenting selected bioactive ligands without risking interference from nonspecifically adsorbed platelet adhesion factors, even in undiluted whole blood and blood plasma. This concept is demonstrated by preparing patterns of proteins on hydrogel surfaces, resulting in highly controlled platelet adhesion. Further insights into the protein immobilization and platelet adhesion processes are provided by studies using imaging surface plasmon resonance. The hydrogel surfaces used in this work appear to provide an ideal platform for cell adhesion studies of platelets, and potentially also for other cell types.

    Ort, förlag, år, upplaga, sidor
    John Wiley & Sons, 2010
    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-54301 (URN)10.1002/adfm.201000083 (DOI)000281058900003 ()
    Tillgänglig från: 2010-03-08 Skapad: 2010-03-08 Senast uppdaterad: 2017-12-12
    6. Swelling of grafted poly(ethylene glycol)-containing hydrogels: a neutron re°ectivity study
    Öppna denna publikation i ny flik eller fönster >>Swelling of grafted poly(ethylene glycol)-containing hydrogels: a neutron re°ectivity study
    (Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    Hydrogels are used to enhance biocompatibility and reduce inflammation in biomedical applications, and as area-enlarging matrices in bioanalytical devices. For either of these applications, the structure of the hydrogel is important for the function, and thus structural understanding of hydrogels in their wet state is highly relevant for the use and development of these materials. Also, processing of these materials is frequently made in ambient air, and it is of interest to relate the properties of dry, or humid air-swollen hydrogels, to their wet properties.

    We use neutron reflectometry to follow the swelling of hydrogels in air of controlled humidity. Comparing hydrogels prepared on silica and gold substrates { both of relevance to bioanalytical applications { we observe that the swelling is different, reflecting a structural difference between these polymers, but that the water content of the polymer films near saturation is near 33% in both cases. Upon immersion in water, the swelling is estimated to approximately 2 x the dry thickness of the polymer, though a consistent quantitative determination of the polymer profile could not be made. Finally, we observe that the hydrogels are unaffected by either positively and negatively charged proteins.

    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-54302 (URN)
    Tillgänglig från: 2010-03-08 Skapad: 2010-03-08 Senast uppdaterad: 2017-01-11
    7. Novel application of imaging surface plasmon resonance for in situ studies of the surface exploration of marine organisms
    Öppna denna publikation i ny flik eller fönster >>Novel application of imaging surface plasmon resonance for in situ studies of the surface exploration of marine organisms
    Visa övriga...
    2009 (Engelska)Ingår i: BIOINTERPHASES, ISSN 1559-4106, Vol. 4, nr 4, s. 65-68Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    The surface interactions of exploring cyprids of the barnacle Semibalanus balanoides were studied in situ using imaging surface plasmon resonance. It was demonstrated how the deposition of a proteinaceous adhesive could be followed in real time as the cyprids explored and temporarily attached to a surface. Furthermore, the amount of protein left on the surface when the cyprids moved on could be quantified. Clear differences were demonstrated between an oligo(ethyleneglycol) coated surface and a bare gold substrate. It is anticipated that this technique will be a valuable tool in the development of novel surface chemistries that can prevent biofouling.

    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-53839 (URN)10.1116/1.3274060 (DOI)000273820500002 ()
    Tillgänglig från: 2010-02-05 Skapad: 2010-02-05 Senast uppdaterad: 2010-03-08
    8. In situ study of surface exploration by barnacle cyprids (Semibalanus balanoides) using imaging surface plasmon resonance
    Öppna denna publikation i ny flik eller fönster >>In situ study of surface exploration by barnacle cyprids (Semibalanus balanoides) using imaging surface plasmon resonance
    Visa övriga...
    (Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    Imaging surface plasmon resonance (iSPR) was employed to investigate the interfacial adhesion phenomena that occur during the exploration of immersed surfaces by barnacle cyprids (Semibalanus balanoides). It was hypothesised that since the footprint material used by cyprids for temporary adhesion has previously been related to a large cuticular glycoprotein (SIPC), the passive deposition of cyprid footprints and the binding of SIPC to surfaces might correlate. Increased surface exploration (and footprint deposition) has also been related to increased likelihood of settlement in barnacle cyprids. If a correlation between footprint deposition and SIPC binding were to exist, therefore, there would be potential for the development of a high‐throughput assay to determine the efficacy of putative antifouling chemistries against cyprids prior to, or instead of, lengthy bio‐assays. Footprints were deposited in large numbers on carboxyl‐terminated self‐assembled monolayers (SAMs) and in very small numbers on ethylene glycol‐containing SAMs and hydrogel coatings. SIPC binding also followed the same trend. An exception to the correlation was an amineterminated SAM that accumulated few cyprid footprints, but bound SIPC strongly. It is concluded that there is great potential for the iSPR technique to be used in the evaluation of putatively non‐fouling surfaces as well as improving our understanding of the nature of the cyprid footprint material and its interactions with surfaces of different chemistry. However, the use of SIPC binding as a predictor of footprint accumulation/likelihood of settlement of cyprids to surfaces would be premature at this stage without first understanding the exceptions highlighted in this study.

    Nationell ämneskategori
    Naturvetenskap
    Identifikatorer
    urn:nbn:se:liu:diva-54303 (URN)
    Tillgänglig från: 2010-03-08 Skapad: 2010-03-08 Senast uppdaterad: 2010-03-08
    Ladda ner fulltext (pdf)
    Hydrogel coatings for biomedical and biofouling applications
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    Cover
  • 62.
    Ekblad, Tobias
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Andersson, Olof
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Tai, Feng-i
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Ederth, Thomas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Liedberg , Bo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Lateral Control of Protein Adsorption on Charged Polymer Gradients2009Ingår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 25, nr 6, s. 3755-3762Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This work describes the fabrication, characterization, and protein adsorption behavior of charged polymer gradients. The thin gradient films were fabricated by a two-step technique using UV-initiated free-radical polymerization in a reactor with a moving shutter. A homogeneous layer of cationic poly(2-aminoethyl methacrylate hydrochloride) was first formed, followed by a layer of oppositely charged poly(2-carboxyethyl acrylate) with a continuously increasing thickness. Adsorption from protein solutions as well as human blood plasma was investigated by imaging surface plasmon resonance and infrared microscopy. The results showed excessive protein adsorption in the areas where one of the polymers dominated the composition, while there was a clear minimum at an intermediate position of the gradient. The charge of the surface was estimated by direct force measurements and found to correlate well with the protein adsorption, showing the lowest net charge in the same area as the protein adsorption minimum. We therefore hypothesize that a combination of the charged polymers, in the right proportions, can result in a protein-resistant surface due to balanced charges.

  • 63.
    Ekblad, Tobias
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Bergström, Gunnar
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Teknisk biologi.
    Ederth, Thomas
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Conlan, Sheelagh L.
    Liu, Yunli
    Zhao, Qi
    DSouza, Fraddry
    Donnelly, GlenT.
    Willemsen, Peter R.
    Pettitt, Michala E.
    Callow, Maureen E.
    Callow, James A.
    Liedberg, Bo
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Poly(ethylene glycol)-Containing Hydrogel Surfaces for Antifouling Applications in Marine and Freshwater Environments2008Ingår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 9, nr 10, s. 2775-2783Artikel i tidskrift (Refereegranskat)
    Abstract [en]

       

  • 64.
    Ekblad, Tobias
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Faxälv, Lars
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Klinisk kemi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Laboratoriemedicinskt centrum, Klinisk kemi.
    Andersson, Olof
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Wallmark, Nanny
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär fysik. Linköpings universitet, Tekniska fakulteten.
    Larsson (Kaiser), Andréas
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Lindahl, Tomas L.
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Klinisk kemi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Laboratoriemedicinskt centrum, Klinisk kemi.
    Liedberg, Bo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Patterned Hydrogels for Controlled Platelet Adhesion from Whole Blood and Plasma2010Ingår i: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 20, nr 15, s. 2396-2403Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This work describes the preparation and properties of hydrogel surface chemistries enabling controlled and well-defined cell adhesion. The hydrogels may be prepared directly on plastic substrates, such as polystyrene slides or dishes, using a quick and experimentally simple photopolymerization process, compatible with photolithographic and microfluidic patterning methods. The intended application for these materials is as substrates for diagnostic cell adhesion assays, particularly for the analysis of human platelet function. The adsorption of fibrinogen and other platelet promoting molecules is shown to be completely inhibited by the hydrogel, provided that the film thickness is sufficient (>5 nm). This allows the hydrogel to be used as a matrix for presenting selected bioactive ligands without risking interference from nonspecifically adsorbed platelet adhesion factors, even in undiluted whole blood and blood plasma. This concept is demonstrated by preparing patterns of proteins on hydrogel surfaces, resulting in highly controlled platelet adhesion. Further insights into the protein immobilization and platelet adhesion processes are provided by studies using imaging surface plasmon resonance. The hydrogel surfaces used in this work appear to provide an ideal platform for cell adhesion studies of platelets, and potentially also for other cell types.

  • 65.
    Ekblad, Tobias
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Liedberg, Bo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Protein adsorption and surface patterning2010Ingår i: CURRENT OPINION IN COLLOID and INTERFACE SCIENCE, ISSN 1359-0294, Vol. 15, nr 6, s. 499-509Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Surface patterning has become an important discipline of biologically oriented surface science over the past decades Many methods have been developed that allow the formation of patterns on the micro- and nanoscalle This Opinion discusses the role of protein adsorption in patterning technologies highlighting how it can be used as an integrated part of the patterning process how it can be controlled by patterns with appropriate properties and how it may lead to disruption of formed patterns if not properly accounted for Recent examples from literature are used to emphasize some of the most interesting developments in the field such as novel surface chemistries only allowing specific protein adsorption directed self-sorting adsorption of proteins on patterned surfaces and control of protein adsorption through nanopatterning

  • 66.
    Ekeroth, Johan
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Björefors, Fredrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Borgh, Annika
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Lundström, Ingemar
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik. Linköpings universitet, Tekniska högskolan.
    Liedberg, Bo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Konradsson, Peter
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Organisk Kemi. Linköpings universitet, Tekniska högskolan.
    Electrochemical Evaluation of the Interfacial Capacitance upon Phosphorylation of Amino Acid Analogue Molecular Films2001Ingår i: Analytical Chemistry, ISSN 0003-2700, Vol. 73, nr 18, s. 4463-4468Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An approach based on electrochemistry to differentiate between phosphorylated and nonphosphorylated amino acid analogues adsorbed on gold is presented. Analogues of serine, threonine, and tyrosine, containing thiohexadecyl headgroups, were synthesized and assembled on gold, and the surface capacitance was evaluated using electrochemical impedance spectroscopy. A procedure for deprotection of tert-butyl phosphate protecting groups, on the monolayer, is also described. Characterizations of the assembled analogues by cyclic voltammetry, infrared spectroscopy, and ellipsometry are used to confirm the insulating properties of the monolayers and the outcome of surface modifications. The results from cyclic voltammetry show good insulating properties for the monolayers even after phosphate deprotection. The infrared measurements reveal well-ordered monolayers, and the thickness from ellipsometry is in good agreement with expectations from molecular modeling. The impedance experiments show a capacitance increase up to 0.6 μF/cm2 as phosphate groups are introduced. The results in this study indicate the possibility of using a surface chemical and impedance spectroscopy approach to detect the kinase/phosphatase activity and kinetics involved in phosphorylation reactions.

  • 67.
    Ekeroth, Johan
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    Borgh, Annika
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Konradsson, Peter
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Organisk Kemi. Linköpings universitet, Tekniska högskolan.
    Liedberg, Bo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Synthesis and Monolayer Characterization of Phosphorylated Amino Acid Analogs2002Ingår i: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 254, nr 2, s. 322-330Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The synthesis of a series of thiols containing phosphorylated and non-phosphorylated serine, threonine, and tyrosine amino acid residues is described. The synthesized molecules, based on 3-mercaptopropionic acid, were assembled onto gold and subsequently characterized using infrared reflection-absorption spectroscopy, ellipsometry, X-ray photoelectron spectroscopy, and contact angle goniometry. The ellipsometric analysis indicates that they form densely packed and well-oriented monolayers on gold, with thicknesses that are in good agreement with estimated values from space-filling models. The bulky and space-demanding phosphorylated threonine analog was, however, found to be an exception. The increase in layer thickness when adding a phosphate group to the threonine is only 35% of that observed for the two other analogs. A detailed infrared examination of the influence of cation coordination to the phosphorylated serine analog using calcium and magnesium reveals structural similarities to those of the inorganic phosphate compound calcium hydroxy apatite. We furthermore discuss the application of these monolayers as soft templates for biomineralization.

  • 68.
    Ekeroth, Johan
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska högskolan.
    Konradsson, Peter
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Organisk Kemi. Linköpings universitet, Tekniska högskolan.
    Björefors, Fredrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Lundström, Ingemar
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik. Linköpings universitet, Tekniska högskolan.
    Liedberg, Bo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Monitoring the interfacial capacitance at self-assembled phosphate monolayers on gold electrodes upon interaction with calcium and magnesium2002Ingår i: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 74, nr 9, s. 1979-1985Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Electrochemical impedance spectroscopy has been used to evaluate the change in interracial capacitance upon calcium and magnesium coordination to a phosphate-modified electrode. The phosphate electrode was prepared via immobilization of phosphorylated, thiol-containing, serine analogues onto gold. Upon subjection to calcium and magnesium, a substantial drop in capacitance was observed. Magnesium displayed the largest influence on the capacitance: a 27% capacitance drop was observed upon introduction of a 1 mM solution of magnesium ions. The lowered capacitance is a result of a change in the potential and charge distribution at the film/electrolyte interface as the cations coordinate to the phosphate groups. Moreover, the relationship between electrode potential and capacitance has been investigated and reveals a significant difference between monovalent and divalent cations. As complementary information, infrared reflection absorption spectra of the phosphorylated monolayer having different counterions are presented. The results reported in this paper indicate that the phosphorylated amino acid analogue monolayers could be used in investigations of the biochemically important coordination of calcium and magnesium to phosphates and phosphorylated amino acids.

  • 69.
    Enander, Karin
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Strategies for improved target quantification in protein microarrays2008Ingår i: 2nd Label-Free Protein Array Workshop,2008, 2008Konferensbidrag (Övrigt vetenskapligt)
  • 70.
    Enander, Karin
    et al.
    Division of Organic Chemistry, Uppsala University.
    Aili, Daniel
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Baltzer, Lars
    Division of Organic Chemistry, Department of Chemistry, BMC, Uppsala University, Uppsala, Sweden.
    Lundström, Ingemar
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik. Linköpings universitet, Tekniska högskolan.
    Liedberg, Bo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Alpha-helix-inducing dimerization of synthetic polypeptide scaffolds on gold2005Ingår i: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 21, nr 6, s. 2480-2487Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Designed, synthetic polypeptides that assemble into four-helix bundles upon dimerization in solution were studied with respect to folding on planar gold surfaces. A model system with controllable dimerization properties was employed, consisting of negatively and positively charged peptides. Circular dichroism spectroscopy and surface plasmon resonance based measurements showed that at neutral pH, the peptides were able to form heterodimers in solution, but unfavorable electrostatic interactions prevented the formation of homodimers. The dimerization propensity was found to be both pH- and buffer-dependent. A series of infrared absorption−reflection spectroscopy experiments of the polypeptides attached to planar gold surfaces revealed that if the negatively charged peptide was immobilized from a loading solution where it was folded, its structure was retained on the surface provided it had a cysteine residue available for anchoring to gold. If it was immobilized as random coil, it remained unstructured on the surface but was able to fold through heterodimerization if subsequently exposed to a positively charged polypeptide. When the positively charged peptide was immobilized as random coil, heterodimerization could not be induced, probably because of high-affinity interactions between the charged primary amine groups and the gold surface. These observations are intended to pave the way for future engineering of functional surfaces based on polypeptide scaffolds where folding is known to be crucial for function.

  • 71.
    Enander, Karin
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Andersson, Linda
    Göteborg universitet.
    Dolphin, Gunnar
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Liedberg, Bo
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Lundström, Ingemar
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik.
    Baltzer, Lars
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Designed, folded polypeptides for bioanalytical purposes - molecular scaffolds that combine recognition and reporting2001Ingår i: 4th International Conference on Structural Molecular Biology,2001, 2001Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

      

  • 72.
    Enander, Karin
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Choulier, L
    Université Louis Pasteur.
    Olsson, Linnéa
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Yushchenko, Dmitry
    Université Louis Pasteur.
    Kanmert, Daniel
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Klymchenko, Andrey
    Université Louis Pasteur.
    Demchenko, A
    Palladin Institute of Biochemistry.
    Mély, Yves
    Université Louis Pasteur.
    Altschuh, Danièle
    Université Louis Pasteur.
    Development of peptide-based ratiometric biosensor constructs for direct fluorescence detection of protein analytes2007Ingår i: VII European Symposium of the Protein Society,2007, 2007Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

        

  • 73.
    Enander, Karin
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Choulier, Laurence
    Université Louis Pasteur.
    Selegård, Linnéa
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Yushchenko, Dmitry
    Université Louis Pasteur.
    Kanmert, Daniel
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Klymchenko, Andrey
    Université Louis Pasteur.
    Demchenko, Alexander
    Palladin Institute of Biochemistry.
    Mély, Yves
    Université Louis Pasteur.
    Altschuh, Danièle
    Université Louis Pasteur.
    A peptide-based, ratiometric biosensor construct for direct fluorescence detection of a protein analyte2008Ingår i: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 19, nr 9, s. 1864-1870Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We present the design, synthesis, and functional evaluation of peptide-based fluorescent constructs for wavelength-ratiometric biosensing of a protein analyte. The concept was shown using the high-affinity model interaction between the 18 amino acid peptide pTMVP and a recombinant antibody fragment, Fab57P. pTMVP was functionalized in two different positions with 6-bromomethyl-2-(2-furanyl)-3-hydroxychromone, an environmentally sensitive fluorophore with a two-band emission. The equilibrium dissociation constant of the interaction between pTMVP and Fab57P was largely preserved upon labeling. The biosensor ability of the labeled peptide constructs was evaluated in terms of the relative intensity change of the emission bands from the normal (N*) and tautomer (T*) excited-state species of the fluorophore (IN*/IT*) upon binding of Fab57P. When the peptide was labeled in the C terminus, the IN*/I T* ratio changed by 40% upon analyte binding, while labeling close to the residues most important for binding resulted in a construct that completely lacked ratiometric biosensor ability. Integrated biosensor elements for reagentless detection, where peptides and ratiometric fluorophores are combined to ensure robustness in both recognition and signaling, are expected to become an important contribution to the design of future protein quantification assays in immobilized formats. © 2008 American Chemical Society.

  • 74.
    Enander, Karin
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Dolphin, Gunnar
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Baltzer, Lars
    Uppsala universitet.
    Structure-dependent signalling in fluorescent biosensor units based on designed, folded polypeptide scaffolds2004Ingår i: 19:e Organikerdagarna,2004, 2004Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

      

  • 75.
    Enander, Karin
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska högskolan.
    Dolphin, Gunnar
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska högskolan.
    Liedberg, Bo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Lundström, Ingemar
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik. Linköpings universitet, Tekniska högskolan.
    Baltzer, Lars
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska högskolan.
    A versatile polypeptide platform for integrated recognition and reporting: affinity arrays for protein-ligand interaction analysis2004Ingår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 10, nr 10, s. 2375-2385Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A molecular platform for protein detection and quantification is reported in which recognition has been integrated with direct monitoring of target-protein binding. The platform is based on a versatile 42-residue helix–loop–helix polypeptide that dimerizes to form four-helix bundles and allows site-selective modification with recognition and reporter elements on the side chains of individually addressable lysine residues. The well-characterized interaction between the model target-protein carbonic anhydrase and its inhibitor benzenesulfonamide was used for a proof-of-concept demonstration. An affinity array was designed where benzenesulfonamide derivatives with aliphatic or oligoglycine spacers and a fluorescent dansyl reporter group were introduced into the scaffold. The affinities of the array members for human carbonic anhydrase II (HCAII) were determined by titration with the target protein and were found to be highly affected by the properties of the spacers (dissociation constant Kd=0.02–3 μM). The affinity of HCAII for acetazolamide (Kd=4 nM) was determined in a competition experiment with one of the benzenesulfonamide array members to address the possibility of screening substance libraries for new target-protein binders. Also, successful affinity discrimination between different carbonic anhydrase isozymes highlighted the possibility of performing future isoform-expression profiling. Our platform is predicted to become a flexible tool for a variety of biosensor and protein-microarray applications within biochemistry, diagnostics and pharmaceutical chemistry.

  • 76.
    Enander, Karin
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Dolphin, Gunnar
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Lundström, Ingemar
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik.
    Liedberg, Bo
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Baltzer, Lars
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    De novo designed helix-loop-helix polypeptides - a structure-function-based design strategy for microarray and biosensor applications2003Ingår i: 1st World Congress on Synthetic Receptors,2003, 2003Konferensbidrag (Refereegranskat)
  • 77.
    Enander, Karin
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Dolphin, Gunnar
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Lundström, Ingemar
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik.
    Liedberg, Bo
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Baltzer, Lars
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Designed, folded polypeptides as functional units in biosensor applications2002Ingår i: 18:e Organikerdagarna,2002, 2002Konferensbidrag (Övrigt vetenskapligt)
  • 78.
    Enander, Karin
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Dolphin, Gunnar
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Löfdahl, Mikael
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Lundström, Ingemar
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik.
    Liedberg, Bo
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Baltzer, Lars
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Designed, folded polypeptides as functional units in surface-based biosensors - versatile scaffolds connecting recognition and reporting2002Ingår i: Europtrode VI,2002, 2002Konferensbidrag (Refereegranskat)
  • 79.
    Enander, Karin
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Dolphin, Gunnar
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Löfdahl, Mikael
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik.
    Lundström, Ingemar
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik.
    Liedberg, Bo
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Baltzer, Lars
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Helix-loop-helix polypeptides as scaffolds for designed biosensing surfaces2002Ingår i: 6th World Congress on Biosensors,2002, 2002Konferensbidrag (Övrigt vetenskapligt)
  • 80.
    Engström, Maria
    et al.
    Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiologi. Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Klasson, Anna
    Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiologi. Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Pedersen, Henrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Vahlberg, Cecillia
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Käll, Per-Olov
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Fysikalisk Kemi. Linköpings universitet, Tekniska högskolan.
    Uvdal, Kajsa
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    High Proton Relaxivity for Gadolinium Oxide Nanoparticles2006Ingår i: Magnetic Resonance Materials in Physics, Biology and Medicine, ISSN 0968-5243, E-ISSN 1352-8661, Vol. 19, nr 4, s. 180-186Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Objective: Nanosized materials of gadolinium oxide can provide high-contrast enhancement in magnetic resonance imaging (MRI). The objective of the present study was to investigate proton relaxation enhancement by ultrasmall (5 to 10 nm) Gd2O3 nanocrystals.

    Materials and methods: Gd2O3 nanocrystals were synthesized by a colloidal method and capped with diethylene glycol (DEG). The oxidation state of Gd2O3 was confirmed by X-ray photoelectron spectroscopy. Proton relaxation times were measured with a 1.5-T MRI scanner. The measurements were performed in aqueous solutions and cell culture medium (RPMI).

    Results: Results showed a considerable relaxivity increase for the Gd2O3–DEG particles compared to Gd-DTPA. Both T 1 and T 2 relaxivities in the presence of Gd2O3–DEG particles were approximately twice the corresponding values for Gd–DTPA in aqueous solution and even larger in RPMI. Higher signal intensity at low concentrations was predicted for the nanoparticle solutions, using experimental data to simulate a T1-weighted spin echo sequence.

    Conclusion: The study indicates the possibility of obtaining at least doubled relaxivity compared to Gd–DTPA using Gd2O3–DEG nanocrystals as contrast agent. The high T 1 relaxation rate at low concentrations of Gd2O3 nanoparticles is very promising for future studies of contrast agents based on gadolinium-containing nanocrystals.

  • 81. Beställ onlineKöp publikationen >>
    Ericsson, Emma
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Biosensor surface chemistry for oriented protein immobilization and biochip patterning2013Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    This licentiate thesis is focused on two methods for protein immobilization to biosensor surfaces for future applications in protein microarray formats. The common denominator is a surface chemistry based on a gold substrate with a self-assembled monolayer (SAM) of functionalized alkanethiolates. Both methods involve photochemistry, in the first case for direct immobilization of proteins to the surface, in the other for grafting a hydrogel, which is then used for protein immobilization.

    Paper I describes the development and characterization of Chelation Assisted Photoimmobilization (CAP), a three-component surface chemistry that allows for covalent attachment and controlled orientation of the immobilized recognition molecule (ligand) and thereby provides a robust sensor surface for detection of analyte in solution. The concept was demonstrated using His-tagged IgG-Fc as the ligand and protein A as the analyte. Surprisingly, as concluded from IR spectroscopy and surface plasmon resonance (SPR) analysis, the binding ability of this bivalent ligand was found to be more than two times higher with random orientation obtained by amine coupling than with homogeneous orientation obtained by CAP. It is suggested that a multivalent ligand is less sensitive to orientation effects than a monovalent ligand and that island formation of the alkanethiolates used for CAP results in a locally high ligand density and steric hindrance.

    Paper II describes the development of nanoscale hydrogel structures. These were photografted on a SAM pattern obtained by dip-pen nanolithography (DPN) and subsequent backfilling. The hydrogel grew fast on the hydrophilic patterns and slower on the hydrophobic background, which contained a buried oligo(ethylene glycol) (OEG) chain. Using IR spectroscopy, it was found that the OEG part was degraded during UV light irradiation and acted as a sacrificial layer. In this process other OEG residues were exposed and acted as new starting points for the self-initiated photografting and photopolymerization (SIPGP). A biotin derivative was immobilized to the hydrogel density pattern and interaction with streptavidin was demonstrated by epifluorescence microscopy.

    Delarbeten
    1. Controlled Orientation and Covalent Attachment of Proteins on Biosensor Surfaces by Chelation Assisted Photoimmobilization
    Öppna denna publikation i ny flik eller fönster >>Controlled Orientation and Covalent Attachment of Proteins on Biosensor Surfaces by Chelation Assisted Photoimmobilization
    Visa övriga...
    2013 (Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    This report presents a novel method for uniform orientation and covalent attachment of proteins to sensing surfaces, termed Chelation Assisted Photoimmobilization (CAP). Alkanethiols terminated with either nitrilotriacetic acid (NTA), benzophenone (BP) or oligo(ethylene glycol) were synthesized and mixed self-assembled monolayers (SAMs) were prepared on gold and thoroughly characterized by infrared reflection absorption spectroscopy (IRAS), ellipsometry and contact angle goniometry. In the process of CAP, NTA chelates Ni2+ and the complex coordinates a His-tagged ligand in an oriented assembly. The ligand is then photoimmobilized via BP, which forms covalent bonds upon UV light activation. The CAP concept was demonstrated using human IgG-Fc modified with C-terminal hexahistidine tags (His-IgGFc) as the ligand and protein A as the analyte.

    In the development of affinity biosensors, uniform orientation of ligand molecules where all analyte binding sites are accessible is often preferred to random orientation. In order to monitor the effect of ligand orientation on analyte response, the ligand-analyte interaction was quantified by surface plasmon resonance analysis, both in the case of CAP and when the ligand was attached by conventional amine coupling on surfaces presenting NTA. Responses were adjusted for differences in ligand immobilization level using IRAS. The normalized analyte response with randomly oriented ligand was 2.5 times higher than that with ligand immobilized by CAP, probably due to molecular crowding effects on the surface and the fact that His-IgGFc is bivalent for protein A. This is a reminder that many other factors than orientation alone may play a decisive role in analyte binding on biosensor surfaces.

    Nyckelord
    Biosensor, Surface chemistry, Protein immobilization, Orientation
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-87929 (URN)
    Tillgänglig från: 2013-01-29 Skapad: 2013-01-28 Senast uppdaterad: 2013-01-31
    2. Functional Hydrogel Density Patterns Fabricated by Dip-Pen Nanolithography and Photografting
    Öppna denna publikation i ny flik eller fönster >>Functional Hydrogel Density Patterns Fabricated by Dip-Pen Nanolithography and Photografting
    Visa övriga...
    2011 (Engelska)Ingår i: SMALL, ISSN 1613-6810, Vol. 7, nr 15, s. 2153-2157Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    n/a

    Ort, förlag, år, upplaga, sidor
    Wiley-VCH Verlag Berlin, 2011
    Nationell ämneskategori
    Teknik och teknologier
    Identifikatorer
    urn:nbn:se:liu:diva-70751 (URN)10.1002/smll.201002278 (DOI)000294361200003 ()
    Anmärkning

    |

    Tillgänglig från: 2011-09-16 Skapad: 2011-09-16 Senast uppdaterad: 2015-05-29
    Ladda ner fulltext (pdf)
    Biosensor surface chemistry for oriented protein immobilization and biochip patterning
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  • 82.
    Ericsson, Emma
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Bui, Lan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Organisk Kemi. Linköpings universitet, Tekniska högskolan.
    Enander, Karin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Konradsson, Peter
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Organisk Kemi. Linköpings universitet, Tekniska högskolan.
    Liedberg, Bo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Oriented Protein Immobilization by Chelate Associated PhotochemistryManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    We demonstrate herein the synthesis, characterization and application of a novel chelateassociated photochemistry (CAP) for oriented and robust attachment of biomolecular ligandsto sensing surfaces. The chelation agent is nitrilotriacetic acid (NTA) which is capable ofcoordinating two histidine (His) molecules in the presence of Nickel. Therefore a ligandmodified with a His-sequence can be attached to NTA to form an oriented assembly ofligands on the sensor surface. The ligand is then covalently bound to the surface via a nearbyphotolabile benzophenone (BP) which attacks C-H bonds upon UV light activation. Theligand is then available for analyte interaction. The synthesized compounds used in this studyare based on the well-known organosulphur surface chemistry for proper attachment to goldsurfaces. Besides the two BP and NTA alkane thiols/disulphides we also synthesized a fillermolecule with an oligo (ethylene glycol) (OEG) tail to fine tune the surface composition andto reduce non-specific binding. Results from surface plasmon resonance (SPR) measurementsusing a Biacore 3000 instrument indicate that up to 55% larger analyte response is obtainedwith CAP as compared to the response obtained with the random orientation achieved byphotoimmobilization alone.

  • 83.
    Ericsson, Emma
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Enander, Karin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Bui, Lan
    Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany.
    Lundström, Ingemar
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik. Linköpings universitet, Tekniska högskolan.
    Konradsson, Peter
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Organisk Kemi. Linköpings universitet, Tekniska högskolan.
    Liedberg, Bo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Controlled Orientation and Covalent Attachment of Proteins on Biosensor Surfaces by Chelation Assisted Photoimmobilization2013Manuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    This report presents a novel method for uniform orientation and covalent attachment of proteins to sensing surfaces, termed Chelation Assisted Photoimmobilization (CAP). Alkanethiols terminated with either nitrilotriacetic acid (NTA), benzophenone (BP) or oligo(ethylene glycol) were synthesized and mixed self-assembled monolayers (SAMs) were prepared on gold and thoroughly characterized by infrared reflection absorption spectroscopy (IRAS), ellipsometry and contact angle goniometry. In the process of CAP, NTA chelates Ni2+ and the complex coordinates a His-tagged ligand in an oriented assembly. The ligand is then photoimmobilized via BP, which forms covalent bonds upon UV light activation. The CAP concept was demonstrated using human IgG-Fc modified with C-terminal hexahistidine tags (His-IgGFc) as the ligand and protein A as the analyte.

    In the development of affinity biosensors, uniform orientation of ligand molecules where all analyte binding sites are accessible is often preferred to random orientation. In order to monitor the effect of ligand orientation on analyte response, the ligand-analyte interaction was quantified by surface plasmon resonance analysis, both in the case of CAP and when the ligand was attached by conventional amine coupling on surfaces presenting NTA. Responses were adjusted for differences in ligand immobilization level using IRAS. The normalized analyte response with randomly oriented ligand was 2.5 times higher than that with ligand immobilized by CAP, probably due to molecular crowding effects on the surface and the fact that His-IgGFc is bivalent for protein A. This is a reminder that many other factors than orientation alone may play a decisive role in analyte binding on biosensor surfaces.

  • 84.
    Ericsson, Emma M
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Bui, Lan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska högskolan.
    Lundström, Ingemar
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik. Linköpings universitet, Tekniska högskolan.
    Konradsson, Peter
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Kemi. Linköpings universitet, Tekniska högskolan.
    Liedberg, Bo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär fysik. Linköpings universitet, Tekniska högskolan.
    Enander, Karin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär fysik. Linköpings universitet, Tekniska högskolan.
    Controlled orientation and covalent attachment of proteins on biosensor surfaces by Chelation Assisted Photoimmobilization2013Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    In the context of surface chemistry for affinity biosensor chips, it is widely accepted that uniform orientation of the immobilized recognition element (ligand) is preferred over random orientation. However, this assumption has often been based on studies where differences in ligand immobilization level have not been taken into account. In this contribution, we present a novel two-step method for homogenous orientation and covalent attachment of proteins to sensing surfaces, called Chelation Assisted Photoimmobilization (CAP). Careful quantification of the effect of ligand orientation on analyte responses was performed by comparing this strategy to immobilization by conventional amine coupling.

     In CAP, the chelation agent is nitrilotriacetic acid (NTA) which chelates Ni2+. A His-tagged ligand forms an oriented assembly when binding Ni2+-NTA and is then covalently bound to the surface via photolabile benzophenone (BP), which attacks C-H bonds upon UV light activation. We relied on a surface chemistry based on self-assembled monolayers (SAMs) of oligo(ethylene glycol) (OEG)-containing alkanethiolates on gold. Alkanethiols terminated with either NTA, BP or OEG were synthesized and mixed SAMs were characterized by infrared reflection absorption spectroscopy (IRAS), ellipsometry and contact angle goniometry. IRAS was also used to quantify ligand immobilization levels obtained either by CAP or by amine coupling via the carboxyl groups of an NTA-presenting surface. The model ligand was human IgG-Fc modified with a C-terminal 6xHis-tag and the analyte was Protein A. The ligand-analyte interaction was quantified by a surface plasmon resonance biosensor.

     Analyte responses were normalized with respect to the ligand amounts obtained by the two immobilization strategies. Interestingly, the normalized analyte response with randomly oriented ligand was >2 times higher than that with ligand immobilized by CAP. This shows that oriented ligand immobilization is not necessarily a means of increasing the sensitivity of a biosensor. Factors that may influence performance include the valency of the ligand and constraints related to the surface chemistry used for orientation.

  • 85.
    Eskhult, Jonas
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    Ulrich, Christian
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik. Linköpings universitet, Tekniska högskolan.
    Björefors, Fredrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Nyholm, Leif
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    Current oscillations during chronoamperometric and cyclic voltammetric measurements in alkaline Cu(II)-citrate solutions2008Ingår i: Electrochimica Acta, ISSN 0013-4686, E-ISSN 1873-3859, Vol. 53, nr 5, s. 2188-2197Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    It is demonstrated that current oscillations can be observed during chronoamperometric and cyclic voltammetric experiments in solutions containing 0.4 M CuSO4 and 1.2 M citrate at pH 11 and 50 °C. The oscillations, which are shown to originate from local variations in the pH, result in the deposition of nanostructured Cu and Cu2O materials. It is concluded that the current oscillations are analogous to the previously described potential oscillations obtained under controlled current conditions in alkaline Cu(II)-lactate, -tartrate and -citrate solutions. Rotating disk electrode results clearly show that the reduction of the Cu(II)-complexes is kinetically controlled and that the rate of the reduction increases with increasing pH and temperature. It is also shown that the presence of a cathodic peak on the anodic scan in the cyclic voltammograms can be used to identify the experimental conditions leading to the spontaneous current (or potential) oscillations. Electrochemical quartz crystal microbalance results indicate that the cathodic peak stems from an increased rate of the reduction of the Cu(II)-citrate complexes due to a rapid increase in the local pH. This causes Cu2O rather than Cu to be deposited which, however, results in a decrease in the local pH and a decreasing current. In situ ellipsometry data confirm that Cu2O deposition replaces that of Cu in the potential region of the cathodic peak. The present findings should facilitate syntheses of nanolayered materials based on spontaneous potential or current oscillations.

  • 86.
    Faxälv, Lars
    et al.
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Klinisk kemi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Laboratoriemedicinskt centrum, Klinisk kemi.
    Ekblad, Tobias
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Liedberg, Bo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Lindahl, Tomas L.
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Klinisk kemi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Laboratoriemedicinskt centrum, Klinisk kemi.
    Blood compatibility of photografted hydrogel coatings2010Ingår i: ACTA BIOMATERIALIA, ISSN 1742-7061, Vol. 6, nr 7, s. 2599-2608Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    In this work we have evaluated the haemocompatibility of different surface modifications, intended for biomaterials and biosensor applications. Polystyrene slides were coated with thin hydrogel films by self-initiated photografting of four different monomers. The hydrogel surface modifications were thoroughly characterized and tested for their protein resistance and ability to facilitate platelet adhesion and activation of the coagulation system. There was very little protein adsorption from human plasma on the hydrogels formed from poly(ethylene glycol) methacrylate (PEGMA) and 2-hydroxyethyl methacrylate (HEMA). Platelet adhesion tests performed under both static and flow conditions showed that these coatings also demonstrated very high resistance towards platelet adhesion. A small amount of platelets were found to adhere to hydrogels formed from ethylene glycol methyl ether methacrylate (EGMEMA) and 2-carboxyethyl methacrylate (CEA). The polystyrene substrates themselves facilitated large amounts of platelet adhesion under both static and flow conditions. Utilizing a novel setup for imaging of coagulation, it was shown that none of the hydrogel surfaces activated the coagulation system to any great extent. We suggest that this simple fabrication method can be used to produce hydrogel coatings with unusually high blood compatibility, suitable for demanding biomaterials applications.

  • 87.
    Filippini, Daniel
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik. Linköpings universitet, Tekniska högskolan.
    Liedberg, Bo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    SENSORS and ACTUATORS B: Chemical Special Issue: in SENSORS AND ACTUATORS B-CHEMICAL, vol 142, issue 2, pg 4052009Övrigt (Övrigt vetenskapligt)
    Abstract [en]

    n/a

  • 88.
    Fortin, Marc-Andre
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Petoral, Rodrigo Jr
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Söderlind, Fredrik
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Käll, Per-Olov
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Fysikalisk Kemi.
    Engström, Maria
    Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för medicin och vård, Medicinsk radiologi. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Uvdal, Kajsa
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Synthesis of gadolinium oxide nanoparticles as a contrast agent in MRI2006Ingår i: Trends in Nanotechnology,2006, 2006Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

           

  • 89.
    Fyrner, Timmy
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Organisk Kemi. Linköpings universitet, Tekniska fakulteten.
    Magnusson, Karin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Organisk Kemi. Linköpings universitet, Tekniska fakulteten.
    Nilsson, Peter
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Organisk Kemi. Linköpings universitet, Tekniska högskolan.
    Hammarström, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biokemi. Linköpings universitet, Tekniska högskolan.
    Aili, Daniel
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Konradsson, Peter
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Organisk Kemi. Linköpings universitet, Tekniska högskolan.
    Derivatization of a bioorthogonal protected trisaccharide linker: towards multimodal tools for chemical biology2012Ingår i: Bioconjugate chemistry, ISSN 1043-1802, E-ISSN 1520-4812, Vol. 23, nr 6, s. 1333-1340Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    When cross-linking biomolecules to surfaces or to other biomolecules, the use of appropriate spacer molecules is of great importance. Mimicking the naturally occurring spacer molecules will give further insight into their role and function, possibly unveil important issues regarding the importance of the specificity of carbohydrate-based anchor moieties, in e.g., glycoproteins and glycosylphosphatidylinositols. Herein, we present the synthesis of a lactoside-based trisaccharide, potentially suitable as a heterobifunctional bioorthogonal linker molecule whereon valuable chemical handles have been conjugated. An amino-derivative having thiol functionality shows promise as novel SPR-surfaces. Furthermore, the trisaccharide has been conjugated to a cholesterol moiety in combination with a fluorophore which successfully assemble on the cell surface in lipid microdomains, possibly lipid-rafts. Finally, a CuI-catalyzed azide-alkyne cycloaddition reaction (CuAAC) confirms the potential use of oligosaccharides as bioorthogonal linkers in chemical biology.

  • 90.
    Gavutis, Martynas
    et al.
    Department of Nanoengineering, Center for Physical Sciences and Technology, Savanorių 231, LT-02300 Vilnius, Lithuania.
    Lee, Hung-Hsun
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    Ruželė, Živilė
    Department of Nanoengineering, Center for Physical Sciences and Technology, Savanorių 231, LT-02300 Vilnius, Lithuania.
    Liedberg, Bo
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Valiokas, Ramūnas
    Department of Nanoengineering, Center for Physical Sciences and Technology, Savanorių 231, LT-02300 Vilnius, Lithuania.
    Tethered Lipid Membrane Formation on Assemblies with Controlled Presentation of Anchor Molecules: A QCM-D StudyManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    We have recently described a binary self-assembled monolayer (SAM) platform for studies of tethered bilayer lipid membrane (tBLM) formation using surface analysis techniques (Lee et al). Namely, this type of mixed SAMs consisted of a matrix molecule, HS-(CH2)15-CONHCH2CH2OH, and an anchor molecule, HS-(CH2)15-CONH-(CH2CH2O)6-CH2CONH-X, where X is -(CD2)7CD3 or -(CD2)15CD3. In the present work, we have employed quartz crystal microbalance with dissipation monitoring (QCM-D) to study in more detail small unilamellar vesicle (SUV) fusion on such SAMs formed from solutions with a range of mole fractions of the anchor. Using the QCM frequency and dissipation signals we were able to relate tBLM formation to the density of surface anchors. The QCM-D analysis revealed a critical SUV concentration on the surface is necessary for vesicle rupture and bilayer formation. We found that the critical SUV concentration decreased with increasing density of anchoring groups. Dissipation signal indicated the most pronounced release of water enclosed by the SUVs (related to vesicle rupturing) for the SAMs formed in the range of mole fractions between 1 and 10%. Also, we observed only minute differences in the behavior of the SUVs on SAMs terminated with -(CD2)7CD3 or -(CD2)15CD3 anchors, respectively.

  • 91.
    Gedefaw, Desta
    et al.
    Gothenburg University.
    Zhou, Yi
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Hellstrom, Stefan
    Chalmers Institute of Technology.
    Lindgren, Lars
    Chalmers Institute of Technology.
    Andersson, L.Mattias
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Zhang, Fengling
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Mammo, Wendimagegn
    Chalmers Institute of Technology.
    Inganäs, Olle
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Andersson, Mats R
    Chalmers Institute of Technology.
    Alternating copolymers of fluorene and donor-acceptor-donor segments designed for miscibility in bulk heterojunction photovoltaics2009Ingår i: JOURNAL OF MATERIALS CHEMISTRY, ISSN 0959-9428, Vol. 19, nr 30, s. 5359-5363Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A novel copolymer based on alternating fluorene and donor-acceptor-donor segments is reported, together with its photovoltaic properties in blends with fullerene derivatives. The balanced electron and hole mobility of the blends leads to a power-conversion efficiency of 2-3% under solar illumination.

  • 92.
    Hamedi, Mahiar
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Wigenius, Jens
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Tai, Feng-i
    Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    Björk, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biomolekylär och Organisk Elektronik. Linköpings universitet, Tekniska högskolan.
    Aili, Daniel
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Polypeptide-guided assembly of conducting polymer nanocomposites2010Ingår i: NANOSCALE, ISSN 2040-3364, Vol. 2, nr 10, s. 2058-2061Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A strategy for fabrication of electroactive nanocomposites with nanoscale organization, based on self-assembly, is reported. Gold nanoparticles are assembled by a polypeptide folding-dependent bridging. The polypeptides are further utilized to recruit and associate with a water soluble conducting polymer. The polymer is homogenously incorporated into the nanocomposite, forming conducting pathways which make the composite material highly conducting.

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  • 93.
    Hansson, Kenny
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Johansen, Knut
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Wetterö, Jonas
    Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för molekylär och klinisk medicin, Reumatologi.
    Klenkar, Goran
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Benesch, Johan
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Lundström, Ingemar
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik.
    Lindahl, Tomas
    Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för biomedicin och kirurgi, Avdelningen för klinisk kemi. Östergötlands Läns Landsting, Laboratoriemedicinskt centrum, Klinisk kemi.
    Tengvall, Pentti
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik.
    Surface plasmon resonance detection of blood coagulation and platelet adhesion under venous and arterial shear conditions2007Ingår i: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 23, nr 2, s. 261-268Artikel i tidskrift (Refereegranskat)
    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.

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  • 94.
    Hedlund, Anna
    et al.
    Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiologi. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Hälsouniversitetet.
    Ahrén, Maria
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Ytors Fysik och Kemi. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Tekniska högskolan.
    Gustafsson, Håkan
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiologi. Linköpings universitet, Hälsouniversitetet.
    Abrikossova, Natalia
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för fysik, kemi och biologi. Linköpings universitet, Tekniska högskolan.
    Warntjes, Marcel
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för medicin och hälsa, Klinisk fysiologi. Linköpings universitet, Hälsouniversitetet.
    Jönsson, Jan-Ingvar
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Experimentell hematologi. Linköpings universitet, Hälsouniversitetet.
    Uvdal, Kajsa
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan.
    Engström, Maria
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för medicin och hälsa, Medicinsk radiologi. Linköpings universitet, Hälsouniversitetet.
    Detection of Gd2O3 Nanoparticles in Hematopoietic Cells for MRI Contrast EnhancementManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    As the utility of magnetic resonance imaging (MRI) broadens, the importance of having specific and efficient contrast agents increases and there has been a huge development in the fields of molecular imaging and intracellular markers.

    Previous studies have shown that gadolinium oxide (Gd2O3 ) nanoparticles generate higher relaxivity than currently available Gd chelates. The Gd2O3 nanoparticles are also promising for MRI cell tracking. The aim of the present work was to study cell labeling with Gd2O3 nanoparticles and to improve techniques for monitoring hematopoietic stem cell migration by MRI.

    We studied particle uptake in two cell lines; the hematopoietic progenitor cell line Ba/F3 and the monocytic cell line THP-1. Cells were incubated with Gd2O3 nanoparticles as well as superparamagnetic iron oxide particles (SPIOs) for comparison. In addition, it was investigated whether the transfection agent protamine sulfate increased the particle uptake. Treated cells were examined by microscopic techniques, MRI and analyzed for particle content.

    Results showed that particles were intracellular, however in Ba/F3 only sparsely. The relaxation times were shortened with increasing particle concentration. Overall relaxivities, r1 and r2 for Gd2O3 nanoparticles in all cell samples measured were 5.1 ± 0.3 and 14.9 ± 0.7 (s-1mM-1) respectively. Goodness of fit was 0.97 in both cases. Protamine sulfate treatment increased the uptake in both Ba/F3 cells and THP-1 cells.

    Viability of treated cells was not significantly decreased and thus, we conclude that the use of Gd2O3 nanoparticles is suitable for this type of cell labeling by means of detecting and monitoring hematopoietic cells.

  • 95. Hellgren, N.
    et al.
    Johansson, Mats P
    Hjorvarsson, B.
    Hjörvarsson, B., Materials Physics, Royal Institute of Technology, Teknikringen 14, S-100 44 Stockholm, Sweden.
    Broitman, E.
    Östblom, Mattias
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Liedberg, Bo
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Hultman, Lars
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik.
    Sundgren, J.-E.
    Growth, structure, and mechanical properties of CNxHy films deposited by dc magnetron sputtering in N2/Ar/H2 discharges2000Ingår i: Journal of Vacuum Science & Technology. A. Vacuum, Surfaces, and Films, ISSN 0734-2101, E-ISSN 1520-8559, Vol. 18, nr 5, s. 2349-2358Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 96.
    Islam, Mohammad Mirazul
    et al.
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelningen för cellbiologi. Linköpings universitet, Medicinska fakulteten. Karolinska Institute, Sweden.
    Ravichandran, Ranjithkumar
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär fysik. Linköpings universitet, Tekniska fakulteten.
    Olsen, D.
    FibroGen Inc, CA 94158 USA.
    Kozak Ljunggren, Monika
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelningen för cellbiologi. Linköpings universitet, Medicinska fakulteten.
    Fagerholm, Per
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelningen för neuro- och inflammationsvetenskap. Linköpings universitet, Medicinska fakulteten. Region Östergötland, Sinnescentrum, Ögonkliniken US/LiM.
    Lee, Chyan-Jang
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik. Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för klinisk och experimentell medicin. Linköpings universitet, Medicinska fakulteten.
    Griffith, May
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelningen för cellbiologi. Linköpings universitet, Medicinska fakulteten. Karolinska Institute, Sweden.
    Phopase, Jaywant
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär fysik. Linköpings universitet, Tekniska fakulteten.
    Self-assembled collagen-like-peptide implants as alternatives to human donor corneal transplantation2016Ingår i: RSC Advances, ISSN 2046-2069, E-ISSN 2046-2069, Vol. 6, nr 61, s. 55745-55749Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Extracellular matrix proteins like collagen promote regeneration as implants in clinical studies. However, collagens are large and unwieldy proteins, making small functional peptide analogs potentially ideal substitutes. Self-assembling collagen-like-peptides conjugated with PEG-maleimide were assembled into hydrogels. When tested pre-clinically as corneal implants in mini-pigs, they promoted cell and nerve regeneration, forming neo-corneas structurally and functionally similar to natural corneas.

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  • 97. Johansen, K
    et al.
    Arwin, Hans
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad optik.
    Lundström, Ingemar
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik.
    Liedberg, Bo
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Imaging surface plasmon resonance sensor based on multiple wavelengths: Sensitivity considerations2000Ingår i: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 71, nr 9, s. 3530-3538Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A new, multiple wavelength surface plasmon resonance apparatus for imaging applications is presented. It can be used for biosensing, e.g., for monitoring of chemical and biological reactions in real time with label-free molecules. A setup with a fixed incident angle in the Kretschmann configuration with gold as the supporting metal is described, both theoretically and experimentally. Simulations of the sensor response based on independently recorded optical (ellipsometric) data of gold show that the sensitivity for three-dimensional recognition layers (bulk) increases with increasing wavelength. For two-dimensional recognition layers (adlayer) maximum sensitivity is obtained within a limited wavelength range. In this situation, the rejection of bulk disturbances, e.g., emanating from temperature variations, decreases, with increasing wavelength. For imaging surface plasmon resonance the spatial resolution decreases with increasing wavelength. Hence, there is always a compromise between spatial resolution, bulk disturbance rejection, and sensitivity. Most importantly, by simultaneously using multiple wavelengths, it is possible to maintain a high sensitivity and accuracy over a large dynamic range. Furthermore, our simulations show that the sensitivity is independent of the refractive index of the prism. (C) 2000 American Institute of Physics. [S0034-6748(00)02909-9].

  • 98.
    Johansen, Knut
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Lundström, Ingemar
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik.
    Liedberg, Bo
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Sensitivity deviation: Instrumental linearity errors that influence concentration analyses and kinetic evaluation of biomolecular interactions2000Ingår i: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 15, nr 9-10, s. 503-509Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Many scientific instruments utilise multiple element detectors, e.g. CCD's or photodiode arrays, to monitor the change in a position of an optical pattern. For example, instruments for affinity biosensing based on surface plasmon resonance (SPR) or resonant mirror are equipped with such detectors. An important and desired property of these bioanalytical instruments is that the calculation of the movement or change in shape follows the true change. This is often not the case and it may lead to linearity errors, and to sensitivity errors. The sensitivity is normally defined as the slope of the calibration curve. A new parameter is introduced to account for the linearity errors, the sensitivity deviation, defined as the deviation from the undistorted slope of the calibration curve. The linearity error and the sensitivity deviation are intimately related and the sensitivity deviation may lead to misinterpretation of kinetic data, mass transport limitations and concentration analyses. Because the linearity errors are small (e.g. 10 pg/mm2 of biomolecules on the sensor surface) with regard to the dynamic range (e.g. 30 000 pg/mm2), they can be difficult to discover. However, the linearity errors are often not negligible with regard to a typical response (e.g. 0-100 pg/mm2), and may therefore cause serious problems. A method for detecting linearity errors is outlined. Further on, this paper demonstrates how integral linearity errors of less than 1% can result in a sensitivity deviation of 10%, a value that in our opinion cannot be ignored in biospecific interaction analysis (BIA). It should also be stressed out that this phenomenon also occurs in other instruments using array detectors. (C) 2000 Elsevier Science S.A.Many scientific instruments utilize multiple element detectors, e.g. CCD's or photodiode arrays, to monitor the change in a position of an optical pattern. For example, instruments for affinity biosensing based on surface plasmon resonance (SPR) or resonant mirror are equipped with such detectors. An important and desired property of these bioanalytical instruments is that the calculation of the movement or change in shape follows the true change. This is often not the case and it may lead to linearity errors, and to sensitivity errors. The sensitivity is normally defined as the slope of the calibration curve. A new parameter is introduced to account for the linearity errors, the sensitivity deviation, defined as the deviation from the undistorted slope of the calibration curve. The linearity error and the sensitivity deviation are intimately related and the sensitivity deviation may lead to misinterpretation of kinetic data, mass transport limitations and concentration analyses. Because the linearity errors are small (e.g. 10 pg/mm2 of biomolecules on the sensor surface) with regard to the dynamic range (e.g. 30 000 pg/mm2), they can be difficult to discover. However, the linearity errors are often not negligible with regard to a typical response (e.g. 0-100 pg/mm2), and may therefore cause serious problems. A method for detecting linearity errors is outlined. Further on, this paper demonstrates how integral linearity errors of less than 1% can result in a sensitivity deviation of 10%, a value that in our opinion cannot be ignored in biospecific interaction analysis (BIA). It should also be stressed out that this phenomenon also occurs in other instruments using array detectors.

  • 99.
    Johansen, Knut
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi.
    Stalberg, R.
    Stålberg, R., Høgskolen i Telemark, Hallvard Eikas plass, 3800 Bø, Norway.
    Lundström, Ingemar
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Tillämpad Fysik.
    Liedberg, Bo
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Surface plasmon resonance: Instrumental resolution using photo diode arrays2000Ingår i: Measurement science and technology, ISSN 0957-0233, E-ISSN 1361-6501, Vol. 11, nr 11, s. 1630-1638Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Surface plasmon resonance (SPR) sensors are used to study biomolecular interactions. We have performed a theoretical analysis of a SPR instrument using a convergent beam, a linear detector with various numbers of pixels and various analogue-to-digital converters (ADCs) with a corresponding resolution ranging from 8 to 16 bits. Studies of small molecules at low concentrations or with low affinities are limited by the instrumental set-up, e.g. by the resolution, linearity and noise. The amplitudes of these parameters are highly dependent on the detector, ADC and dip-finding algorithm used. We have studied several dip-finding algorithms, e.g. intensity measurements, second- and third-order polynomial fits and centroid algorithms. Each algorithm used with the ADC and the detector has a resolution associated with it. Some algorithms also have an intrinsic algorithm error that is dependent on the number of pixels and the shape of the dip. A weighted centroid algorithm that has an excellent overall performance is described. If an accuracy of 10-6 refractive index units (RIU) is satisfactory, a 12-bit ADC and a 64-pixel detector are appropriate. Theoretically, by using a 16-bit ADC and a 1024-pixel detector, a resolution of better than 10-9 RIU is obtainable.

  • 100.
    Jonsson, Bengt-Harald
    et al.
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär Bioteknik.
    Broo, Klas
    Lundqvist, Martin
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Molekylär Bioteknik.
    Nygren, Patrik
    Linköpings universitet, Tekniska högskolan. Linköpings universitet, Institutionen för fysik, kemi och biologi, Sensorvetenskap och Molekylfysik.
    Design of Functional Peptide-Nanoparticle Complexes with Potential Applications in Targeted Drug Delivery2008Ingår i: BITs 6th annual congress of 2008 International drug discovery science and technology,2008, 2008, s. 142-143Konferensbidrag (Övrigt vetenskapligt)
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