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  • 1.
    Abramavicius, V.
    et al.
    Vilnius University, Lithuania; Centre Phys Science and Technology, Lithuania.
    Pranculis, V.
    Centre Phys Science and Technology, Lithuania.
    Melianas, Armantas
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Gulbinas, V.
    Centre Phys Science and Technology, Lithuania.
    Abramavicius, D.
    Vilnius University, Lithuania.
    Role of coherence and delocalization in photo-induced electron transfer at organic interfaces2016In: Scientific Reports, E-ISSN 2045-2322, Vol. 6, no 32914Article in journal (Refereed)
    Abstract [en]

    Photo-induced charge transfer at molecular heterojunctions has gained particular interest due to the development of organic solar cells (OSC) based on blends of electron donating and accepting materials. While charge transfer between donor and acceptor molecules can be described by Marcus theory, additional carrier delocalization and coherent propagation might play the dominant role. Here, we describe ultrafast charge separation at the interface of a conjugated polymer and an aggregate of the fullerene derivative PCBM using the stochastic Schrodinger equation (SSE) and reveal the complex time evolution of electron transfer, mediated by electronic coherence and delocalization. By fitting the model to ultrafast charge separation experiments, we estimate the extent of electron delocalization and establish the transition from coherent electron propagation to incoherent hopping. Our results indicate that even a relatively weak coupling between PCBM molecules is sufficient to facilitate electron delocalization and efficient charge separation at organic interfaces.

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  • 2.
    Adam, Stefan
    et al.
    Leibniz Institute Polymerforsch eV, Germany; Technical University of Dresden, Germany.
    Koenig, Meike
    Leibniz Institute Polymerforsch eV, Germany; Technical University of Dresden, Germany; Karlsruhe Institute Technology, Germany.
    Rodenhausen, Keith Brian
    University of Nebraska, NE 68588 USA; Biolin Science Inc, NJ 07652 USA.
    Eichhorn, Klaus-Jochen
    Leibniz Institute Polymerforsch eV, Germany.
    Oertel, Ulrich
    Leibniz Institute Polymerforsch eV, Germany.
    Schubert, Mathias
    Linköping University, Department of Physics, Chemistry and Biology, Semiconductor Materials. Linköping University, Faculty of Science & Engineering. Leibniz Institute Polymerforsch eV, Germany; University of Nebraska, NE 68588 USA; University of Nebraska, NE 68588 USA.
    Stamm, Manfred
    Leibniz Institute Polymerforsch eV, Germany; Technical University of Dresden, Germany.
    Uhlmann, Petra
    Leibniz Institute Polymerforsch eV, Germany; University of Nebraska, NE 68588 USA.
    Quartz crystal microbalance with coupled Spectroscopic Ellipsometry-study of temperature-responsive polymer brush systems2017In: Applied Surface Science, ISSN 0169-4332, E-ISSN 1873-5584, Vol. 421, p. 843-851Article in journal (Refereed)
    Abstract [en]

    Using a combined setup of quartz crystal microbalance with dissipation monitoring together with spectroscopic ellipsometry, the thermo-responsive behavior of two different brush systems (poly(N-isopropyl acrylamide) and poly(2-oxazoline)s) was investigated and compared to the behavior of the free polymer in solution. Poly(2-oxazoline)s with three different hydrophilicities were prepared by changing the content of a hydrophilic comonomer. While both polymer types exhibit a sharp, discontinuous thermal transition in solution, in the brush state the transition gets broader in the case of poly(N-isopropyl acrylamide) and is transformed into a continuous transition for poly(2-oxazoline)s. The position of the transition in solution is influenced by the degree of hydrophilicity of the poly(2-oxazoline). The difference in areal mass detected by quartz crystal microbalance and by spectroscopic ellipsometry, has been attributed to the chain segment density profile of the polymer brushes. Applying this density profile information, for poly(N-isopropyl acrylamide) two different swelling stages could be identified, while for poly(2-oxazoline) the transition between a parabolic and more step-wise profile is found continuous. The different swelling characteristics were attributed to the different miscibility behavior types, with the brush state acting similar to a crosslinked system. (C) 2017 Elsevier B.V. All rights reserved.

  • 3.
    Ajjan, Fátima
    et al.
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Mecerreyes, David
    Univ Basque Country UPV EHU, Spain.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Enhancing Energy Storage Devices with Biomacromolecules in Hybrid Electrodes2019In: Biotechnology Journal, ISSN 1860-6768, E-ISSN 1860-7314, Vol. 14, no 12, article id 1900062Article, review/survey (Refereed)
    Abstract [en]

    The development of energy storage devices with higher energy and power outputs, and long cycling stability is urgently required in the pursuit of the expanding challenges of electrical energy storage. The utilization of biologically renewable redox compounds holds a great potential in designing sustainable energy storage systems and contributes in reducing the dependence on fossil fuels for energy materials. Quinones are the principal redox centers in natural organic materials and play a key role as charge storage electrode materials because of their abundance, multiple forms and integration into the materials flow through the biosphere. Electrical energy storage devices and systems can be significantly improved by the combination of scalable quinone-based biomaterials with good electronic conductors. This review uses recent examples to show how biopolymers are providing new directions in the development of renewable biohybrid electrodes for energy storage devices.

  • 4.
    Aleckovic, Ehlimana
    et al.
    Linköping University, Department of Physics, Chemistry and Biology.
    Andersson, Linnea
    Linköping University, Department of Physics, Chemistry and Biology.
    Chamoun, Sherley
    Linköping University, Department of Physics, Chemistry and Biology.
    Einarsson, Ellen
    Linköping University, Department of Physics, Chemistry and Biology.
    Ekstedt, Ebba
    Linköping University, Department of Physics, Chemistry and Biology.
    Eriksen, Emma
    Linköping University, Department of Physics, Chemistry and Biology.
    Madan-Andersson, Maria
    Linköping University, Department of Physics, Chemistry and Biology.
    Method Development for Determining the Stability of Heat Stable Proteins Combined with Biophysical Characterization of Human Calmodulin and the Disease Associated Variant D130G2016Independent thesis Basic level (degree of Bachelor), 10,5 credits / 16 HE creditsStudent thesis
    Abstract [en]

    Calmodulin is a highly conserved calcium ion binding protein expressed in all eukaryotic species. The 149 amino acid residues in the primary structure are organized in seven α helices with the highly flexible central α helix connecting the two non-cooperative domains of calmodulin. Each domain contains two EF-hand motifs to which calcium ions bind in a cooperative manner, hence the binding of four calcium ions saturate one calmodulin molecule. In the cardiovascular area calmodulin is involved in the activation of cardiac muscle contraction, and mutations that arise in the genetic sequence of the protein often have severe consequences. One such consequential mutation that can arise brings about the replacement of the highly conserved aspartic acid with glycine at position 130 in the amino acid sequence. In this research, the thermal and chemical stability within the C domain of the D130G variant of human calmodulin was investigated using a new method only requiring circular dichroism spectroscopic measurements. Affinity studies within the C domain of the D130G variant of human calmodulin were performed using fluorescence spectroscopy, and the ligands chosen for this purpose were trifluoperazine and p- HTMI. All analytical experiments were performed with the C domain of wild type human calmodulin as a reference. From the new method, it was concluded that the C domain of the D130G variant of human calmodulin has a slightly decreased stability in terms of Tm and Cm values compared to the C domain of wild type human calmodulin. The affinity analyses indicated that neither trifluoperazine nor p-HTMI discriminates between the C domain of the D130G variant of human calmodulin and the C domain of wild type human calmodulin in terms of dissociation constants. The pivotal outcome from this research is that the new method is applicable for determination of the stability parameters Tm and Cm of heat stable proteins. 

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  • 5.
    Amaia Beatriz, Ortega-Santos
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Sensor and Actuator Systems. Linköping University, Faculty of Science & Engineering.
    Martinez, Jose Gabriel
    Linköping University, Department of Physics, Chemistry and Biology, Sensor and Actuator Systems. Linköping University, Faculty of Science & Engineering.
    Jager, Edwin
    Linköping University, Department of Physics, Chemistry and Biology, Sensor and Actuator Systems. Linköping University, Faculty of Science & Engineering.
    Enzymatic biofuel cells embedded polymer-based soft actuators2022Conference paper (Other academic)
    Abstract [en]

    Enzymatic biofuel cells are presented as an untethered alternative energy source that could power small implantable or wearable medical devices. However, most of these catalytic processes do not provide with enough energy to power common small electronic-mechanical devices. On the other hand, conducting polymer-based actuators are of great interest for their biocompatibility, flexibility, processability, possibility to be miniaturized and low power consumption. So far, these artificial muscles have been driven by external power sources that prevent them for being completely autonomous. There is a need for a novel power source to elaborate actuators that could use physiological processes as a driving force. These soft actuators’ low power consumption matches the electrical power generated by the biocatalysis of some enzymes, such as glucose oxidase and laccase in presence of glucose and oxygen in aqueous media. Here, we present the latest results in the development of polypyrrole-based soft actuators powered by enzymatic biofuel cells. The actuator consists of a tri-layer conductive substrate on which the polypyrrole is electrodeposited in both sides. The polypyrrole layers act as the active part, expanding and contracting upon a redox reaction, resulting in a bending movement. Tetrathiofulvlene-7,7,8,8-tetracyanoquinodimethane (TTF-TCNQ) and 2,2′-azino-di-(3-ethylbenzthiazoline sulfonic acid) (ABTS) electron transfer mediators are cast on the surface of the polypyrrole to help the electron transmission. The glucose oxidase and laccase enzymes are immobilized in the modified-conducting polymer surface, integrating the electrode to the actuator. The bio-catalysis of enzymes in presence of glucose and oxygen in aqueous solution provides the actuator with the electrons needed for the redox reaction, converting the chemical energy into mechanical energy, i.e., movement. The glucose-self-powered soft actuator may contribute to the development of more complex implantable, ingestible, or wearable biomedical devices such as cardio-stimulators, insulin pumps, or muscle implants.

  • 6.
    Amaia Beatriz, Ortega-Santos
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Sensor and Actuator Systems. Linköping University, Faculty of Science & Engineering.
    Martinez, Jose Gabriel
    Linköping University, Department of Physics, Chemistry and Biology, Sensor and Actuator Systems. Linköping University, Faculty of Science & Engineering.
    Jager, Edwin
    Linköping University, Department of Physics, Chemistry and Biology, Sensor and Actuator Systems. Linköping University, Faculty of Science & Engineering.
    The effect of enzyme immobilization methods in polypyrrole-based soft actuators driven by glucose and O22023Conference paper (Other academic)
  • 7.
    Andersson, Felicia
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry.
    A Quantum Chemical Investigation of Chemical Vapour Deposition of Fe using Ferrocene and Plasma Electrons2023Independent thesis Advanced level (degree of Master (Two Years)), 40 credits / 60 HE creditsStudent thesis
    Abstract [en]

    Thin films provide a remarkable asset, as depositing a thin surface layer can completely alter a material’s characteristics and provide new, inexpensive, and valuable properties. In 2020, a new Chemical Vapour Deposition (CVD) approach was developed at Linköping University, using plasma electrons as reducing agents for the deposition of metallic thin films. To understand the CVD approach, comprehension of the deposition chemistry is crucial. In this thesis, I have performed a theoretical examination of the gas phase and surface chemistry of ferrocene in the recently developed CVD method to form metallic iron thin films, using plasma electrons as reducing agents. Results show that ferrocene anion formation and dissociation are probable in the gas phase, depending on the energy of the plasma electrons. It gets successively easier to dissociate the complex after gaining electrons. The most probable gas phase species leading to film formation was determined as FeCp2-, FeCp, and Cp− under the normal deposition parameters. An electron energy above 220 kJ/mol would suffice for ion formation and dissociation to form FeCp and Cp− fragments. On the surface, ferrocene’s vertical and horizontal adsorption is equally probable, with energies around -72 kJ/mol. Cp, Fe, and FeCp with Fe facing towards the surface interacts stronger with the surface than ferrocene, with adsorption energies of -179, -279 kJ/mol, and -284 kJ/mol. FeCp with Fe facing up from the surface had adsorption energy of -23 kJ/mol. As the surface bonding of Fe and FeCp with Fe facing the surface is stronger than for the other species, this poses a possible way of tuning the CVD method to limit carbon impurities. By providing above 180 kJ/mol energy, for example in the form of heating the substrate, the unwanted species FeCp2, Cp, and FeCp with the ring facing downwards would desorb from the surface, leaving the Fe and FeCp fragments with iron facing towards the surface still adsorbed. This poses a possible way of reducing carbon impurities.

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    A Quantum Chemical Investigation of Chemical Vapour Deposition of Fe using Ferrocene and Plasma Electrons
  • 8.
    Anusuyadevi, Prasaanth Ravi
    et al.
    Royal Inst Technol KTH, Sweden.
    Shanker, Ravi
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Cui, Yuxiao
    Royal Inst Technol KTH, Sweden.
    Riazanova, Anastasia V
    Royal Inst Technol KTH, Sweden.
    Järn, Mikael
    RISE Res Inst Sweden, Sweden.
    Jonsson, Magnus
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Svagan, Anna J.
    Royal Inst Technol KTH, Sweden.
    Photoresponsive and Polarization-Sensitive Structural Colors from Cellulose/Liquid Crystal Nanophotonic Structures2021In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 33, no 36, article id 2101519Article in journal (Refereed)
    Abstract [en]

    Cellulose nanocrystals (CNCs) possess the ability to form helical periodic structures that generate structural colors. Due to the helicity, such self-assembled cellulose structures preferentially reflect left-handed circularly polarized light of certain colors, while they remain transparent to right-handed circularly polarized light. This study shows that combination with a liquid crystal enables modulation of the optical response to obtain light reflection of both handedness but with reversed spectral profiles. As a result, the nanophotonic systems provide vibrant structural colors that are tunable via the incident light polarization. The results are attributed to the liquid crystal aligning on the CNC/glucose film, to form a birefringent layer that twists the incident light polarization before interaction with the chiral cellulose nanocomposite. Using a photoresponsive liquid crystal, this effect can further be turned off by exposure to UV light, which switches the nematic liquid crystal into a nonbirefringent isotropic phase. The study highlights the potential of hybrid cellulose systems to create self-assembled yet advanced photoresponsive and polarization-tunable nanophotonics.

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  • 9. Order onlineBuy this publication >>
    Aronsson, Christopher
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Physics. Linköping University, Faculty of Science & Engineering.
    Tunable and modular assembly of polypeptides and polypeptide-hybrid biomaterials2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Biomaterials are materials that are specifically designed to be in contact with biological systems and have for a long time been used in medicine. Examples of biomaterials range from sophisticated prostheses used for replacing outworn body parts to ordinary contact lenses. Currently it is possible to create biomaterials that can e.g. specifically interact with cells or respond to certain stimuli. Peptides, the shorter version of proteins, are excellent molecules for fabrication of such biomaterials. By following and developing design rules it is possible to obtain peptides that can self-assemble into well-defined nanostructures and biomaterials.

    The aim of this thesis is to create ”smart” and tunable biomaterials by molecular self-assembly using dimerizing –helical polypeptides. Two different, but structurally related, polypeptide-systems have been used in this thesis. The EKIV-polypeptide system was developed in this thesis and consists of four 28-residue polypeptides that can be mixed-and-matched to self-assemble into four different coiled coil heterodimers. The dissociation constant of the different heterodimers range from μM to < nM. Due to the large difference in affinities, the polypeptides are prone to thermodynamic social self-sorting. The JR-polypeptide system, on the other hand, consists of several 42-residue de novo designed helix-loop-helix polypeptides that can dimerize into four-helix bundles. In this work, primarily the glutamic acid-rich polypeptide JR2E has been explored as a component in supramolecular materials. Dimerization was induced by exposing the polypeptide to either Zn2+, acidic conditions or the complementary polypeptide JR2K.

    By conjugating JR2E to hyaluronic acid and the EKIV-polypeptides to star-shaped poly(ethylene glycol), respectively, highly tunable hydrogels that can be self-assembled in a modular fashion have been created. In addition, self-assembly of spherical superstructures has been investigated and were obtained by linking two thiol-modified JR2E polypeptides via a disulfide bridge in the loop region. ŒThe thesis also demonstrates that the polypeptides and the polypeptide-hybrids can be used for encapsulation and release of molecules and nanoparticles. In addition, some of the hydrogels have been explored for 3D cell culture. By using supramolecular interactions combined with bio-orthogonal covalent crosslinking reactions, hydrogels were obtained that enabled facile encapsulation of cells that retained high viability.

    The results of the work presented in this thesis show that dimerizing α–helical polypeptides can be used to create modular biomaterials with properties that can be tuned by specific molecular interactions. The modularity and the tunable properties of these smart biomaterials are conceptually very interesting andmake them useful in many emerging biomedical applications, such as 3D cell culture, cell therapy, and drug delivery

    .

    List of papers
    1. Self-sorting heterodimeric coiled coil peptides with defined and tuneable self-assembly properties
    Open this publication in new window or tab >>Self-sorting heterodimeric coiled coil peptides with defined and tuneable self-assembly properties
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    2015 (English)In: Scientific Reports, E-ISSN 2045-2322, Vol. 5, no 14063Article in journal (Refereed) Published
    Abstract [en]

    Coiled coils with defined assembly properties and dissociation constants are highly attractive components in synthetic biology and for fabrication of peptide-based hybrid nanomaterials and nanostructures. Complex assemblies based on multiple different peptides typically require orthogonal peptides obtained by negative design. Negative design does not necessarily exclude formation of undesired species and may eventually compromise the stability of the desired coiled coils. This work describe a set of four promiscuous 28-residue de novo designed peptides that heterodimerize and fold into parallel coiled coils. The peptides are non-orthogonal and can form four different heterodimers albeit with large differences in affinities. The peptides display dissociation constants for dimerization spanning from the micromolar to the picomolar range. The significant differences in affinities for dimerization make the peptides prone to thermodynamic social self-sorting as shown by thermal unfolding and fluorescence experiments, and confirmed by simulations. The peptides self-sort with high fidelity to form the two coiled coils with the highest and lowest affinities for heterodimerization. The possibility to exploit self-sorting of mutually complementary peptides could hence be a viable approach to guide the assembly of higher order architectures and a powerful strategy for fabrication of dynamic and tuneable nanostructured materials.

    Place, publisher, year, edition, pages
    NATURE PUBLISHING GROUP, 2015
    National Category
    Physical Sciences Electrical Engineering, Electronic Engineering, Information Engineering
    Identifiers
    urn:nbn:se:liu:diva-121739 (URN)10.1038/srep14063 (DOI)000361177400001 ()26370878 (PubMedID)
    Note

    Funding Agencies|Swedish Research Council (VR); Swedish Foundation for Strategic Research (SSF)

    Available from: 2015-10-06 Created: 2015-10-05 Last updated: 2022-09-15
    2. Tailoring Supramolecular Peptide-Poly(ethylene glycol) Hydrogels by Coiled Coil Self-Assembly and Self-Sorting
    Open this publication in new window or tab >>Tailoring Supramolecular Peptide-Poly(ethylene glycol) Hydrogels by Coiled Coil Self-Assembly and Self-Sorting
    2016 (English)In: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 17, no 6, p. 2260-2267Article in journal (Refereed) Published
    Abstract [en]

    Physical hydrogels are extensively used in a wide range of biomedical applications. However, different applications require hydrogels with different mechanical and structural properties. Tailoring these properties demands exquisite control over the supramolecular peptides with different affinities for dimerization. Four different mechanical properties of hydrogels using de novo designed coiled coil interactions involved. Here we show that it is possible to control the nonorthogonal peptides, designed to fold into four different coiled coil heterodimers with dissociation constants spanning from mu M to pM, were conjugated to star-shaped 4-arm poly(ethylene glycol) (PEG). The different PEG-coiled coil conjugates self-assemble as a result of peptide heterodimerization. Different combinations of PEG peptide conjugates assemble into PEG peptide networks and hydrogels with distinctly different thermal stabilities, supramolecular, and rheological properties, reflecting the peptide dimer affinities. We also demonstrate that it is possible to rationally modulate the self-assembly process by means of thermodynamic self-sorting by sequential additions of nonpegylated peptides. The specific interactions involved in peptide dimerization thus provides means for programmable and reversible self-assembly of hydrogels with precise control over rheological properties, which can significantly facilitate optimization of their overall performance and adaption to different processing requirements and applications.

    Place, publisher, year, edition, pages
    AMER CHEMICAL SOC, 2016
    National Category
    Polymer Chemistry
    Identifiers
    urn:nbn:se:liu:diva-130135 (URN)10.1021/acs.biomac.6b00528 (DOI)000377924800038 ()27219681 (PubMedID)
    Note

    Funding Agencies|Swedish Research Council [621-2011-4319]; Swedish Foundation for Strategic Research [ICA10-0002]; Linkoping University; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009 00971]

    Available from: 2016-07-12 Created: 2016-07-11 Last updated: 2019-01-22
    3. Zinc-Triggered Hierarchical Self-Assembly of Fibrous Helix-Loop-Helix Peptide Superstructures for Controlled Encapsulation and Release
    Open this publication in new window or tab >>Zinc-Triggered Hierarchical Self-Assembly of Fibrous Helix-Loop-Helix Peptide Superstructures for Controlled Encapsulation and Release
    2016 (English)In: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 49, no 18, p. 6997-7003Article in journal (Refereed) Published
    Abstract [en]

    We demonstrate a novel route for hierarchical self-assembly of sub-micrometer-sized peptide superstructures that respond to subtle changes in Zn2+ concentration. The self-assembly process is triggered by a specific folding-dependent coordination of Zn2+ by a de novo designed nonlinear helix-loop-helix peptide, resulting in a propagating fiber formation and formation of spherical superstructures. The superstructures further form larger assemblies that can be completely disassembled upon removal of Zn2+ or degradation of the nonlinear peptide. This flexible and reversible assembly strategy of the superstructures enables facile encapsulation of nanoparticles and drugs that can be released by means of different stimuli.

    Place, publisher, year, edition, pages
    AMER CHEMICAL SOC, 2016
    National Category
    Polymer Chemistry
    Identifiers
    urn:nbn:se:liu:diva-132215 (URN)10.1021/acs.macromol.6b01724 (DOI)000384399100030 ()
    Note

    Funding Agencies|Swedish Research Council [621-2011-4319]; Swedish Foundation for Strategic Research [ICA10-0002]; Linkoping University; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009 00971]

    Available from: 2016-10-26 Created: 2016-10-21 Last updated: 2019-01-22
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    Tunable and modular assembly of polypeptides and polypeptide-hybrid biomaterials
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  • 10.
    Arrigan, Damien
    et al.
    NMRC, University College, Cork, Ireland.
    Ghita, Mihaela
    University of Salford, UK.
    Beni, Valerio
    NMRC, University College, Cork, Ireland.
    Selective voltammetric detection of dopamine in the presence ofascorbate2004In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, no 6, p. 732-733Article in journal (Refereed)
    Abstract [en]

    The selective detection of dopamine in the presence of ascorbateis demonstrated based on the voltammetry of dopamine transferacross the interface between two immiscible electrolyte solutions(ITIES) facilitated by an organic-phase ionophore; ascorbatetransfer does not occur, leading to highly selectivedetection of dopamine in the presence of excess ascorbate.

  • 11.
    Arwin, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    Adsorption of proteins at solid surfaces2018In: Ellipsometry of functional organic surfaces and films / [ed] Karsten Hinrichs, Klaus-Jochen Eichhorn, Cham: Springer, 2018, 2, Vol. Sidorna 31-48, p. 31-48Chapter in book (Other academic)
    Abstract [en]

    Ellipsometry has a very high thin film sensitivity and can resolve sub-nm changes in the thickness of protein film on solid substrates. Being a technique based on photons in and photons out it can also be applied ad solid-liquid interfaces. Ellipsometry has therefore found many in situ applications on protein layer dynamics but studies of protein layer structure are also frequent. Numerous ex situ applications on detection and quantification of protein layers are found and several biosensing concepts have been proposed. In this chapter, the use of ellipsometry in the above mentioned areas is reviewed and experimental methodology including cell design is briefly discussed. The classical ellipsometric challenge to determine both thickness and refractive index of a thin film is addressed and an overview of strategies to determine surface mass density is given. Included is also a discussion about spectral representations of optical properties of a protein layer in terms of a model dielectric function concept and its use for analysis of protein layer structure.

  • 12.
    Arwin, Hans
    Linköping University, Department of Physics, Chemistry and Biology, Thin Film Physics. Linköping University, Faculty of Science & Engineering.
    TIRE and SPR-enhanced SE for adsorption processes2018In: Ellipsometry of functional organic surfaces and films / [ed] Karsten Hinrichs, Klaus-Jochen Eichhorn, Cham: Springer, 2018, Vol. Sidorna 419-435, p. 419-435Chapter in book (Other academic)
    Abstract [en]

    Ellipsometry configurations in internal reflection mode facilitate studies of adsorption processes without the light beam passing through the medium from which adsorption accurs. Monitoring of adsorption processes on surfaces in opaque media is thus possible. If the surface in addition has a thin semitransparent metal film in which surface plasmon polaritons can be excited, one can achieve very high sensitivity to small changes in surface mass density of an adsorbed biolayer. Thickness changes as small as on pm can be resolved. In this chapter the theory for Total Internal Reflection Ellipsometry (TIRE), also called surface plasmon resonance enhanced ellipsometry, will be described and instrumentation will be briefly discussed. TIRE applied in spectroscopic as well as in angle of incidence interrogation modes will be considered. Finally applications in the areas of bioadsorption processes, biosensing, gas adsorption and biolayer imaging will be reviewed.

  • 13.
    Ashaduzzaman, Md
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering. University of Dhaka, Bangladesh.
    Anto Antony, Aswathi
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Murugan, N. Arul
    Royal Institute Technology, Sweden.
    Deshpande, Swapneel R.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Tiwari, Ashutosh
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering. Tekidag AB, UCS, S-58330 Linkoping, Sweden.
    Studies on an on/off-switchable immunosensor for troponin T2015In: Biosensors & bioelectronics, ISSN 0956-5663, E-ISSN 1873-4235, Vol. 73, p. 100-107Article in journal (Refereed)
    Abstract [en]

    Regeneration is a key goal in the design of immunosensors. In this study, we report the temperature-regulated interaction of N-isopropylacrylamide (PNIPAAm) functionalised cardiac troponin T (cTnT) with anti-cTnT. Covalently bonded PNIPAAm on an anti-cTnT bioelectrode showed on/off-switchability, regeneration capacity and temperature triggered sensitivity for cTnT. Above the lower critical solution temperature (LCST), PNIPAAm provides a liphophilic microenvironment with specific volume reduction at the bioelectrode surface, making available binding space for cTnT, and facilitating analyte recognition. Computational studies provide details about the structural changes occurring at the electrode above and below the LCST. Furthermore, free energies associated with the binding of cTnT with PNIPAAm at 25 (Delta G(coil)=-6.0 Kcal/mole) and 37 degrees C (Delta G(globular)=-41.0 kcal/mole) were calculated to elucidate the interaction and stability of the antigen-antibody complex. The responsiveness of such assemblies opens the way for miniaturised, smart immuno-technologies with built-in programmable interactions of antigen-antibody upon receiving stimuli.

  • 14.
    Ashaduzzaman, Md.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering. UCS, Institute Adv Mat, Teknikringen 4A,Mjardevi Science Pk, SE-58330 Linkoping, Sweden.
    Deshpande, Swapneel R.
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering. UCS, Institute Adv Mat, Teknikringen 4A,Mjardevi Science Pk, SE-58330 Linkoping, Sweden.
    Arul Murugan, N.
    Royal Institute Technology, Sweden.
    Kumar Mishra, Yogendra
    University of Kiel, Germany.
    Turner, Anthony
    Linköping University, Department of Physics, Chemistry and Biology, Biosensors and Bioelectronics. Linköping University, Faculty of Science & Engineering.
    Tiwari, Ashutosh
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering. UCS, Institute Adv Mat, Teknikringen 4A,Mjardevi Science Pk, SE-58330 Linkoping, Sweden; Vinoba Bhave Research Institute, India.
    On/off-switchable LSPR nano-immunoassay for troponin-T2017In: Scientific Reports, E-ISSN 2045-2322, Vol. 7, article id 44027Article in journal (Refereed)
    Abstract [en]

    Regeneration of immunosensors is a longstanding challenge. We have developed a re-usable troponin-T (TnT) immunoassay based on localised surface plasmon resonance (LSPR) at gold nanorods (GNR). Thermosensitive poly(N-isopropylacrylamide) (PNIPAAM) was functionalised with anti-TnT to control the affinity interaction with TnT. The LSPR was extremely sensitive to the dielectric constant of the surrounding medium as modulated by antigen binding after 20 min incubation at 37 degrees C. Computational modelling incorporating molecular docking, molecular dynamics and free energy calculations was used to elucidate the interactions between the various subsystems namely, IgG-antibody (c. f., anti-TnT), PNIPAAM and/or TnT. This study demonstrates a remarkable temperature dependent immuno-interaction due to changes in the PNIPAAM secondary structures, i.e., globular and coil, at above or below the lower critical solution temperature (LCST). A series of concentrations of TnT were measured by correlating the lambda(LSPR) shift with relative changes in extinction intensity at the distinct plasmonic maximum (i. e., 832 nm). The magnitude of the red shift in lambda(LSPR) was nearly linear with increasing concentration of TnT, over the range 7.6 x 10(-15) to 9.1 x 10(-4) g/mL. The LSPR based nano-immunoassay could be simply regenerated by switching the polymer conformation and creating a gradient of microenvironments between the two states with a modest change in temperature.

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  • 15.
    Atakan, Aylin
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Erdtman, Edvin
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Mäkie, Peter
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Ojamäe, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Odén, Magnus
    Linköping University, Department of Physics, Chemistry and Biology, Nanostructured Materials. Linköping University, Faculty of Science & Engineering.
    Time evolution of the CO2 hydrogenation to fuels over Cu-Zr-SBA-15 catalysts2018In: Journal of Catalysis, ISSN 0021-9517, E-ISSN 1090-2694, Vol. 362, p. 55-64Article in journal (Refereed)
    Abstract [en]

    Time evolution of catalytic CO2 hydrogenation to methanol and dimethyl ether (DME) has been investigated in a high-temperature high-pressure reaction chamber where products accumulate over time. The employed catalysts are based on a nano-assembly composed of Cu nanoparticles infiltrated into a Zr doped SiOx mesoporous framework (SBA-15): Cu-Zr-SBA-15. The CO2 conversion was recorded as a function of time by gas chromatography-mass spectrometry (GC-MS) and the molecular activity on the catalyst’s surface was examined by diffuse reflectance in-situ Fourier transform infrared spectroscopy (DRIFTS). The experimental results showed that after 14 days a CO2 conversion of 25% to methanol and DME was reached when a DME selective catalyst was used which was also illustrated by thermodynamic equilibrium calculations. With higher Zr content in the catalyst, greater selectivity for methanol and a total 9.5% conversion to methanol and DME was observed, yielding also CO as an additional product. The time evolution profiles indicated that DME is formed directly from methoxy groups in this reaction system. Both DME and methanol selective systems show the thermodynamically highest possible conversion.

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  • 16.
    Augusto Berrocal, Jose
    et al.
    Eindhoven University of Technology, Netherlands.
    Di Meo, Florent
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Chemistry. Linköping University, Faculty of Science & Engineering. University of Limoges, France.
    Garcia-Iglesias, Miguel
    Eindhoven University of Technology, Netherlands.
    Gosens, Ronald P. J.
    Eindhoven University of Technology, Netherlands.
    Meijer, E. W.
    Eindhoven University of Technology, Netherlands.
    Linares, Mathieu
    Linköping University, Department of Physics, Chemistry and Biology, Bioinformatics. Linköping University, Faculty of Science & Engineering.
    Palmans, Anja R. A.
    Eindhoven University of Technology, Netherlands.
    Consequences of conformational flexibility in hydrogen-bond-driven self-assembly processes2016In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 52, no 72, p. 10870-10873Article in journal (Refereed)
    Abstract [en]

    We report the synthesis and self-assembly of chiral, conformationally flexible C-3-symmetrical trisamides. A strong Cotton effect is observed for the supramolecular polymers in linear alkanes but not in cyclic alkanes. MD simulations suggest 2:1 conformations of the amides within the aggregates in both types of solvents, but a chiral bias in only linear alkanes.

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  • 17.
    Baldwin, William J.
    et al.
    Univ Cambridge, England.
    Liang, Xia
    Imperial Coll London, England.
    Klarbring, Johan
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering. Imperial Coll London, England.
    Dubajic, Milos
    Univ Cambridge, England.
    Dell Angelo, David
    Unita Cagliari, Italy.
    Sutton, Christopher
    Univ South Carolina, SC 29208 USA.
    Caddeo, Claudia
    Unita Cagliari, Italy.
    Stranks, Samuel D.
    Univ Cambridge, England.
    Mattoni, Alessandro
    Unita Cagliari, Italy.
    Walsh, Aron
    Imperial Coll London, England.
    Csanyi, Gabor
    Univ Cambridge, England.
    Dynamic Local Structure in Caesium Lead Iodide: Spatial Correlation and Transient Domains2023In: Small, ISSN 1613-6810, E-ISSN 1613-6829Article in journal (Refereed)
    Abstract [en]

    Metal halide perovskites are multifunctional semiconductors with tunable structures and properties. They are highly dynamic crystals with complex octahedral tilting patterns and strongly anharmonic atomic behavior. In the higher temperature, higher symmetry phases of these materials, several complex structural features are observed. The local structure can differ greatly from the average structure and there is evidence that dynamic 2D structures of correlated octahedral motion form. An understanding of the underlying complex atomistic dynamics is, however, still lacking. In this work, the local structure of the inorganic perovskite CsPbI3 is investigated using a new machine learning force field based on the atomic cluster expansion framework. Through analysis of the temporal and spatial correlation observed during large-scale simulations, it is revealed that the low frequency motion of octahedral tilts implies a double-well effective potential landscape, even well into the cubic phase. Moreover, dynamic local regions of lower symmetry are present within both higher symmetry phases. These regions are planar and the length and timescales of the motion are reported. Finally, the spatial arrangement of these features and their interactions are investigated and visualized, providing a comprehensive picture of local structure in the higher symmetry phases.

  • 18.
    Bantikassegn, W.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, Faculty of Science & Engineering.
    Dannetun, Per
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Applied Physics. Linköping University, Faculty of Science & Engineering.
    Salaneck, William R.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering.
    Absence of Schottky barrier formation in junctions of Al and polypyrrole-polyelectrolyte polymer complexes1993In: Thin Solid Films, ISSN 0040-6090, E-ISSN 1879-2731, Vol. 224, no 2, p. 232-236Article in journal (Refereed)
    Abstract [en]

    Thin films of conducting polypyrrole doped with large polymeric anions of polystyrene-sulphonate are electrochemically prepared to study the metal/polymer junctions. Aluminium and gold contacts are vacuum deposited to form metal/polymer/gold sandwich structures for current-voltage characterization. Photoelectron spectroscopy, using UV and X-ray photons, is carried out to investigate the possible causes of current limitation in the Al/PPy(PSS) junction.

  • 19.
    Bantikassegn, W.
    et al.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering.
    Dannetun, Per
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering.
    Salaneck, William R.
    Linköping University, Department of Physics, Chemistry and Biology. Linköping University, Faculty of Science & Engineering.
    Proceedings of the International Conference on Science and Technology of Synthetic Metals Electronic properties of polypyrrole (polystyrene-sulphonate)/metal junctions1993In: Synthetic metals, ISSN 0379-6779, E-ISSN 1879-3290, Vol. 55, no 1, p. 36-42Article in journal (Refereed)
    Abstract [en]

    The nature of polymer/metal interfaces is decisive for the operation of polymer based electronic devices. At such interfaces charge transport may be affected by barrier formation, or by formation of insulating interfaces of various types. We have prepared thin films of conducting polypyrrole doped with large polymeric anions of polystyrenesulphonate for studies in metal/polymer junctions. Aluminium and gold contacts are vacuum deposited to form metal/polymer/gold sandwich structures. The current-voltage characteristics show that the interface between polypyrrole and gold is ohmic with no current limitation. However, the aluminium/polypyrrole interface forms highly resistive and nonohmic contacts. Photoelectron spectroscopy using UV and X-ray photons reveals a decrease of the work function upon Al deposition, reactions between Al and the sulphonate anions, and immediate oxidation of the aluminium upon exposure to oxygen. These observations corroborate the interpretation that the current limitation found at Al/polypyrrole junctions is due to formation of insulating aluminium oxide, not excluding reactions between the metal and dopant. It is also pointed out that interfaces between reactive metals and polymers are prone to such oxide interface formation, considering the high diffusivity of oxygen in many polymers.

  • 20.
    Bao, Qinye
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering. Key Laboratory of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai, P.R. China.
    Liu, Xianjie
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Braun, Slawomir
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Yanqing, Li
    Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, P.R. China.
    Jianxin, Tang
    Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, P.R. China.
    Chungang, Duan
    Key Laboratory of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai, P.R. China.
    Fahlman, Mats
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Intermixing Effect on Electronic Structures of TQ1:PC71BM Bulk Heterojunction in Organic Photovoltaics2017In: Solar RRL, E-ISSN 2367-198X, Vol. 1, no 10, article id 1700142Article in journal (Refereed)
    Abstract [en]

    The interface energetics and intermixing effects of the donor/acceptor bulk heterojunction (BHJ) blends of poly[2,3‐bis‐(3‐octyloxyphenyl) quinoxaline‐5, 8‐dilyl‐alt‐thiophene‐2, 5‐diyl]: [6,6]‐phenyl C71butyric acid methyl ester (TQ1:PC71BM) have been investigated using ultraviolet photoemission spectroscopy (UPS) in combination with the integer charge transfer model. The TQ1:PC71BM represents the useful model system for BHJ organic photovoltaics featuring effective charge generation and transport. It finds out that the positive integer charge state of TQ1 are equal in energy to the negative integer charge state of PC71BM, leading to a negligible potential step at TQ1:PC71BM interface and thus the vacuum level alignment. It is observed that the TQ1 accumulates on the top of TQ1:PC71BM BHJ and UPS spectra as function of various blend ratios suggest that the TQ1 mixes finely with PC71BM with the little work function modification in a wide range. In addition, no significant influence of the long‐range Coulomb interactions or the intermolecular hybridization on the occupied electronic structures is present for the well‐intermixed TQ1:PC71BM BHJs. These findings provide deep insights into the properties of BHJ blends and are beneficial for the performance optimization in organic photovoltaics.

  • 21.
    Beek, WJE
    et al.
    Eindhoven University of Technology, Netherlands.
    Wienk, MM
    Eindhoven University of Technology, Netherlands.
    Kemerink, Martijn
    Eindhoven University of Technology, Netherlands.
    Yang, XN
    Eindhoven University of Technology, Netherlands.
    Janssen, RAJ
    Eindhoven University of Technology, Netherlands.
    Hybrid zinc oxide conjugated polymer bulk heterojunction solar cells2005In: Journal of Physical Chemistry B, ISSN 1520-6106, E-ISSN 1520-5207, Vol. 109, no 19, p. 9505-9516Article in journal (Refereed)
    Abstract [en]

    Bulk heterojunction photovoltaic devices based on blends of a conjugated polymer poly [2-methoxy-5-(3,7-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV) as electron donor and crystalline ZnO nanoparticles (nc-ZnO) as electron acceptor have been studied. Composite nc-ZnO:MDMO-PPV films were cast from a common solvent mixture. Time-resolved pump-probe spectroscopy revealed that a photoinduced electron transfer from MDMO-PPV to nc-ZnO occurs in these blends on a sub-picosecond time scale and produces a long-lived (milliseconds) charge-separated state. The photovoltaic effect in devices, made by sandwiching the active nc-ZnO:MDMO-PPV layer between charge-selective electrodes, has been studied as a function of the ZnO concentration and the thickness of the layer. We also investigated changing the degree and type of mixing of the two components through the use of a surfactant for ZnO and by altering the size and shape of the nc-ZnO particles. Optimized devices have an estimated AM1.5 performance of 1.6% with incident photon to current conversion efficiencies up to 50%. Photoluminescence spectroscopy, atomic force microscopy, and transmission electron microscopy have been used to gain insight in the morphology of these blends.

  • 22.
    Belonoshko, Anatoly B.
    et al.
    Royal Inst Technol KTH, Sweden.
    Fu, Jie
    Ningbo Univ, Peoples R China.
    Bryk, Taras
    Natl Acad Sci Ukraine, Ukraine.
    Simak, Sergey
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    Mattesini, Maurizio
    Univ Complutense Madrid, Spain; UCM, Spain.
    Low viscosity of the Earths inner core2019In: Nature Communications, E-ISSN 2041-1723, Vol. 10, article id 2483Article in journal (Refereed)
    Abstract [en]

    The Earths solid inner core is a highly attenuating medium. It consists mainly of iron. The high attenuation of sound wave propagation in the inner core is at odds with the widely accepted paradigm of hexagonal close-packed phase stability under inner core conditions, because sound waves propagate through the hexagonal iron without energy dissipation. Here we show by first-principles molecular dynamics that the body-centered cubic phase of iron, recently demonstrated to be thermodynamically stable under the inner core conditions, is considerably less elastic than the hexagonal phase. Being a crystalline phase, the body-centered cubic phase of iron possesses the viscosity close to that of a liquid iron. The high attenuation of sound in the inner core is due to the unique diffusion characteristic of the body-centered cubic phase. The low viscosity of iron in the inner core enables the convection and resolves a number of controversies.

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  • 23. Order onlineBuy this publication >>
    Bengtsson, Katarina
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, Faculty of Science & Engineering.
    Additive manufacturing methods and materials for electrokinetic systems2015Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Fabrication of miniaturized devices is usually time-consuming, costly, and the materials commonly used limit the structures that are possible to create. The techniques most often used to make microsystems involve multiple steps, where each step takes considerable time, and if only a few systems are to be made, the price per device becomes excessive. This thesis describes how a simple syringebased 3D-printer, in combination with an appropriate choice of materials, can reduce the delay between design and prototype and simplify fabrication of microsystems. This thesis suggest two types of materials that we propose be used in combination with 3D-printing to further develop microsystems for biology and biochemistry.

    Analytical applications in biology and biochemistry often contain electrodes, such as in gel electrophoresis. Faradaic (electrochemical) reactions have to occur at the metal electrodes to allow electron-to-ion transduction through an electrolyte-based system to drive a current when a potential is applied to the electrodes in an electrolyte-based system. These electrochemical reactions at the electrodes, such as water electrolysis, are usually problematic when miniaturizing devices and analytical systems. An alternative to metal electrodes can be electrochemicallyactive conducting polymers, e.g. poly(3,4-ethylenedioxythiophene) (PEDOT), which can be used to reduce electrolysis when driving a current through water-based systems. Paper 1 describes gel electrophoresis where the platinum electrodes were replaced with the conductive polymer PEDOT, without affecting the separation.

    Manufacturing and prototyping of microsystems can be simplified by using 3Dprinting in combination with a sacrificial material. A sacrificial template material can further simplify bottom-up manufacturing of more complicated forms such as protruding and overhanging structures. We showed in paper 2 that polyethylene glycol (PEG), in combination with a carbonate-based plasticizer, functions well as a 3D-printable sacrificial template material. PEG2000 with between 20 wt% and 30 wt% ethylene carbonate or propylene carbonate has properties advantageous for 3D-printing, such as shear-thinning rheology, mechanical and chemical stability, and easy dissolution in water.

    List of papers
    1. Conducting Polymer Electrodes for Gel Electrophoresis
    Open this publication in new window or tab >>Conducting Polymer Electrodes for Gel Electrophoresis
    2014 (English)In: PLOS ONE, E-ISSN 1932-6203, Vol. 9, no 2, p. 0089416-Article in journal (Refereed) Published
    Abstract [en]

    In nearly all cases, electrophoresis in gels is driven via the electrolysis of water at the electrodes, where the process consumes water and produces electrochemical by-products. We have previously demonstrated that p-conjugated polymers such as poly(3,4-ethylenedioxythiophene) (PEDOT) can be placed between traditional metal electrodes and an electrolyte to mitigate electrolysis in liquid (capillary electroosmosis/electrophoresis) systems. In this report, we extend our previous result to gel electrophoresis, and show that electrodes containing PEDOT can be used with a commercial polyacrylamide gel electrophoresis system with minimal impact to the resulting gel image or the ionic transport measured during a separation.

    Place, publisher, year, edition, pages
    Public Library of Science, 2014
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-105901 (URN)10.1371/journal.pone.0089416 (DOI)000331711900141 ()
    Available from: 2014-04-14 Created: 2014-04-12 Last updated: 2021-06-14Bibliographically approved
    2. Plasticized polyethylene glycol as sacrificial support and template material for syringe-based 3D-printing
    Open this publication in new window or tab >>Plasticized polyethylene glycol as sacrificial support and template material for syringe-based 3D-printing
    2015 (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    Syringe-based 3D-printing is a powerful additive manufacturing method for fabricating short runs (small volumes) of components from multiple materials with a wide range of viscosities. However, objects that are hollow or not in complete contact with the printer’s stage are difficult to fabricate. Using a sacrificial template as a supporting layer enables bottom-up construction of complex structures. Template materials based on polyethylene glycol (PEG) plasticized with organic carbonates to tune their rheological (shear-thinning) and thermal (crystallization) properties have been evaluated, including results from rheometry, differential scanning calorimetry, dissolution rate, chemical compatibility with  polydimethylsiloxane (PDMS), and general functionality in a syringe-based 3D-printer. A family of such blends yields material that is easily printed, is stable over time, is soluble in water, and can support other materials and larger structures without collapsing. These mixtures are proposed for use with other extrudable or mouldable materials to enable 3D-printed devices with complex unsupported geometries.

    Keywords
    3D-Printing, polyethylene glycol, organic carbonates, sacrificial template, extrusion
    National Category
    Physical Sciences Physical Chemistry
    Identifiers
    urn:nbn:se:liu:diva-121250 (URN)
    Available from: 2015-09-10 Created: 2015-09-10 Last updated: 2015-09-10Bibliographically approved
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    Additive manufacturing methods and materials for electrokinetic systems
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  • 24.
    Bengtsson, Katarina
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Mindemark, Jonas
    Department of Chemistry – Ångström Laboratory, Uppsala University, Uppsala, Sweden.
    Brandell, Daniel
    Department of Chemistry – Ångström Laboratory, Uppsala University, Uppsala, Sweden.
    Robinson, Nathaniel D
    Linköping University, Department of Physics, Chemistry and Biology, Surface Physics and Chemistry. Linköping University, The Institute of Technology.
    Plasticized polyethylene glycol as sacrificial support and template material for syringe-based 3D-printing2015Manuscript (preprint) (Other academic)
    Abstract [en]

    Syringe-based 3D-printing is a powerful additive manufacturing method for fabricating short runs (small volumes) of components from multiple materials with a wide range of viscosities. However, objects that are hollow or not in complete contact with the printer’s stage are difficult to fabricate. Using a sacrificial template as a supporting layer enables bottom-up construction of complex structures. Template materials based on polyethylene glycol (PEG) plasticized with organic carbonates to tune their rheological (shear-thinning) and thermal (crystallization) properties have been evaluated, including results from rheometry, differential scanning calorimetry, dissolution rate, chemical compatibility with  polydimethylsiloxane (PDMS), and general functionality in a syringe-based 3D-printer. A family of such blends yields material that is easily printed, is stable over time, is soluble in water, and can support other materials and larger structures without collapsing. These mixtures are proposed for use with other extrudable or mouldable materials to enable 3D-printed devices with complex unsupported geometries.

  • 25.
    Bertilsson, Lars
    Linköping University, Department of Physics, Measurement Technology, Biology and Chemistry. Linköping University, The Institute of Technology.
    Molecular Adsorption on Self Assembled Monolayers studied by Surface Acoustic Waves and Infrared Spectroscopy1997Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Chemical sensors based on the selective absorption of gas/vapors in polymer layers rely on molecular interactions. Details of the mechanisms involved can be obtained by studying the adsorption on well defined model organic surfaces. In this thesis, the adsorption of dimethylmethylphosphonate (DMMP), a model molecule for the nerve gas, sarin, and the influence of humidity on the interaction, have been studied. Well defined organic interfaces were obtained by solution self assembly of long chain co-substituted thiol molecules, SH-(CH2)m-X, on gold surfaces. The interfacial properties are given by the tail group X and the following three different functional groups, -CH3, -OH, -COOH, have been analyzed.

    In the first paper, the properties of the self assembled monolayers (SAMs) were examined. The monolayers form ordered semi-crystalline layers with the tail groups defining the chemical properties of the interfaces. In mixed monolayers the surface concentration of the OH and CH3 terminated thiols corresponds to that of the preparation solution and no signs of macroscopic phase separation could be observed.

    The equilibrium adsorption of DMMP was analyzed under sensor conditions by a surface acoustic wave sensor (SAW), sensitive to changes in surface mass, and infrared reflection absorption spectroscopy (IRAS). It was found that DMMP interacts with hydrogen bond donating groups and that the lone pair electrons of the P=O oxygen is the main interacting part of the molecule. Both the temperature programmed desorption of DMMP adsorbed at 100 K and the SAW results from room temperature measurements indicate that the strongest interaction is on the -COOH surface followedby -OH and -CH3. For the -OH surface there is also a surface coverage dependent in the strength of interaction.

    The influence of humidity on the interaction was studied as DMMP was allowed to adsorb at different levels of relative humidity. For the -OH surface, an increase in the DMMP coverage proportional to the relative humidity was observed both with the SAW and with IRAS. A closer examination, however, revealed that a loss of water occurred during adsorption of DMMP. The conclusion from this experiment is that SAW results and other mass sensitive devices must be corrected if competing adsorption takes place. For the -COOH surface, low humidities tend to increase the DMMP coverage but at higher humidities a clear loss was registered by IRAS and the SAW sensor even after compensation for changes in water coverage. As water is present, the increased interaction can be explained by hydrogen bonding to free OH of the water. On the -COOH surface, the adsorption sites become blocked by water, which is more tightly bound on this surface. In the mixed (OH / CH3) monolayers water vapor starts to influence the DMMP adsorption above a critical concentration of OH groups of 0.6. This is also the OH concentration above which total wetting with DMMP occurs.

    The well defined organic monolayers formed by solution self-assembly was found to be suitable for interaction studies of the hydrogen bond accepting DMMP molecule and the influence of humidity on the interaction. The complementary information resulting from the chosen analytical techniques can be used for both qualitative and quantitative evaluation of the adsorption. For example, an optimal composition for the mixed (OH/CH3) SAM has been identified, where the number of adsorption sites and the interaction is sufficiently high, and the influence from humidity still low.

    List of papers
    1. Interaction of dimethyl methylphosphonate with alkanethiolate monolayers studied by temperature-programmed desorption and infrared spectroscopy
    Open this publication in new window or tab >>Interaction of dimethyl methylphosphonate with alkanethiolate monolayers studied by temperature-programmed desorption and infrared spectroscopy
    1997 (English)In: JOURNAL OF PHYSICAL CHEMISTRY B, ISSN 1089-5647, Vol. 101, no 31, p. 6021-6027Article in journal (Refereed) Published
    Abstract [en]

    The adsorption of dimethyl methylphosphonate (DMMP) on well-defined organic surfaces consisting of self-assembled monolayers (SAMs) of omega-substituted alkanethiolates on gold has been studied. Three different surfaces were examined: one terminated with -OH groups (Au/S-(CH2)(16)-OH), one with -CH3 (Au/S-(CH2)(15)-CH3), and one mixed surface with approximately equal amounts of -OH and -CH3 terminated thiols. Detailed information about the nature and strength of the interaction was gathered by infrared reflection-absorption spectroscopy and temperature-programmed desorption under ultrahigh-vacuum conditions. It is found that the outermost functional groups of the thiol monolayer have a pronounced impact on the interaction with DMMP at low coverage. The -OH surface, allowing for hydrogen bonds with the P=O part of the DMMP molecule, increases the strength of interaction by approximately 3.8 kJ/mol as compared to the -CH3 surface. A preadsorbed layer of D2O leads to stronger interaction on all surfaces. This is explained by additional hydrogen bond formation between free O-D at the ice-vacuum interface and DMMP.

    Place, publisher, year, edition, pages
    AMER CHEMICAL SOC, 1997
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-76335 (URN)10.1021/jp9707605 (DOI)A1997XP10700015 ()
    Available from: 2012-04-04 Created: 2012-04-03 Last updated: 2022-02-09
    2. Adsorption of dimethyl methylphosphonate on self-assembled alkanethiolate monolayers
    Open this publication in new window or tab >>Adsorption of dimethyl methylphosphonate on self-assembled alkanethiolate monolayers
    Show others...
    1998 (English)In: JOURNAL OF PHYSICAL CHEMISTRY B, ISSN 1089-5647, Vol. 102, no 7, p. 1260-1269Article in journal (Refereed) Published
    Abstract [en]

    The adsorption of dimethyl methylphosphonate (DMMP), a model molecule for sarin, on three different organic interfaces, prepared by solution self-assembly of alkanethiols on gold, was followed by a surface acoustic wave mass sensor and infrared reflection-absorption spectroscopy at room temperature. The surfaces, characterized by the following tail groups (-OH, -CH3, -COOH), show both quantitative and qualitative differences concerning the interaction with DMMP, the acid surface giving rise to the strongest adsorption. Results obtained in UHV, at low temperatures using infrared spectroscopy and temperature-programmed desorption, support this observation and give complementary information about the nature of the interaction. The hydrogen-bond-accepting properties of the P=O part of DMMP and its impact on the design of sensing interfaces based on hydrogen bonding, as well as the use of self-assembled monolayers to study molecular interactions, are discussed.

    Place, publisher, year, edition, pages
    AMER CHEMICAL SOC, 1998
    National Category
    Engineering and Technology
    Identifiers
    urn:nbn:se:liu:diva-76333 (URN)10.1021/jp973215c (DOI)000072131500027 ()
    Available from: 2012-04-04 Created: 2012-04-03 Last updated: 2022-02-09
  • 26.
    Bian, Bian
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Electronic and photonic materials. Linköping University, Faculty of Science & Engineering.
    Musumeci, Chiara
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Wang, Chuan Fei
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Skallberg, Andreas
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Chen, Yongzhen
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Hu, Zhang-Jun
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Münger, Peter
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    Uvdal, Kajsa
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Surface Physics and Nano Science. Linköping University, Faculty of Science & Engineering.
    Fahlman, Mats
    Linköping University, Department of Science and Technology, Laboratory of Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Inganäs, Olle
    Linköping University, Department of Physics, Chemistry and Biology, Electronic and photonic materials. Linköping University, Faculty of Science & Engineering.
    Nanocontacts give efficient hole injection in organic electronics2021In: Science Bulletin, ISSN 2095-9273, Vol. 66, no 9, p. 875-879Article in journal (Other academic)
    Abstract [en]

    n/a

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  • 27.
    Björk, Jonas
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Chemistry. Linköping University, Faculty of Science & Engineering.
    Formation mechanisms of covalent nanostructures from density functional theory2016In: Proceedings of International Workshop on On-Surface Synthesis, Cham: Springer, 2016, p. 269-287Conference paper (Refereed)
    Abstract [en]

    In this chapter, it is demonstrated how electronic structure calculations, with focus on density functional theory, can be used to gain insight about on-surface reactions. I first give a brief introduction to how density functional theory can be used to study reactions. The focus is then shifted to two different types of on-surface reactions, highlighting the theoretical work that has been performed to gain detailed atomistic insight into them. First, the state of the art of the theory behind on-surface Ullmann coupling is described. In this reaction, molecular building blocks dehalogenate, which enables them to covalently couple. The most crucial reaction parameters are identified—the diffusion and coupling barriers of surface-supported radicals—and the potential for theory to optimize these is discussed. We then concentrate on the homo-coupling between terminal alkynes, a rudimentarily different process where molecules initially couple before undergoing a dehydrogenation step. The theory of the mechanism behind this coupling strategy is less developed than that of the on-surface Ullmann coupling, where fundamental questions remain to be unraveled. For example, by the subtle change of substrate from Ag to Au, the on-surface alkyne chemistry is completely altered from the homo-coupling to a cyclodehydrogenation reaction for the same molecular building block, of which origin remains unknown. The main objective of the chapter is to give an impression of what kind of information theory can obtain about reaction on surface, as well as to motivate and inspire for future theoretical studies, which will be needed to turn on-surface synthesis into a more predictive discipline.

  • 28.
    Björk, Jonas
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Chemistry. Linköping University, Faculty of Science & Engineering.
    Reaction mechanisms for on-surface synthesis of covalent nanostructures2016In: Journal of Physics: Condensed Matter, ISSN 0953-8984, E-ISSN 1361-648X, Vol. 28, no 8, p. 083002-Article, review/survey (Refereed)
    Abstract [en]

    In recent years, on-surface synthesis has become an increasingly popular strategy to form covalent nanostructures. The approach has great prospects for facilitating the manufacture of a range of fascinating materials with atomic precision. However, the on-surface reactions are enigmatic to control, currently restricting its bright perspectives and there is a great need to explore how the reactions are governed. The objective of this topical review is to summarize theoretical work that has focused on comprehending on-surface synthesis protocols through studies of reaction mechanisms.

  • 29.
    Björk, Jonas
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Chemistry. Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    Thermodynamics of an Electrocyclic Ring-Closure Reaction on Au(111)2016In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 120, no 38, p. 21716-21721Article in journal (Refereed)
    Abstract [en]

    We have computationally studied the effects of temperature on the reaction pathway of an electrocyclic ring-closure reaction on the Au(111) surface, particularly focusing on thermodynamic aspects of the reaction. The electrocyclic ring closure is accompanied by a series of dehydrogenation steps, and while it is found that temperature, in terms of vibrational entropy and enthalpy, has a reducing effect on most energy barriers, it does not alter the qualitative appreciation of the reaction kinetics. However, it is found that the way the abstracted hydrogen atoms are treated is crucial for the thermodynamics of the reaction. The overall reaction is highly endothermic but becomes thermodynamically favorable due to the entropy gain of the hydrogen byproducts, which desorb associatively from the surface as H2. The study provides new outlooks for the theoretical treatment of reactions related to on-surface synthesis, anticipated to be instructive for future studies.

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  • 30.
    Björk, Jonas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Computational Physics. Linköping University, The Institute of Technology.
    Hanke, Felix
    Accelrys, 334 Science Park, Cambridge, CB4 0WN, United Kingdom.
    Towards Design Rules for Covalent Nanostructures on Metal Surfaces2014In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 20, no 4, p. 928-934Article in journal (Refereed)
    Abstract [en]

    The covalent molecular assembly on metal surfaces is explored, outlining the different types of applicable reactions. Density functional calculations for on-surface reactions are shown to yield valuable insights into specific reaction mechanisms and trends across the periodic table. Finally, it is shown how design rules could be derived for nanostructures on metal surfaces.

  • 31.
    Björk, Jonas
    et al.
    University of Liverpool, UK.
    Hanke, Felix
    University of Liverpool, UK.
    Palma, Carlos-Andres
    University de Strasbourg, France.
    Samorì, Paolo
    University de Strasbourg, France.
    Cecchini, Marco
    University de Strasbourg, France.
    Persson, Mats
    University of Liverpool, UK.
    Adsorption of Aromatic and Anti-Aromatic Systems on Graphene through π−π Stacking2010In: Journal of Physical Chemistry Letters, ISSN 1948-7185, E-ISSN 1948-7185, Vol. 1, p. 3407-3412Article in journal (Refereed)
    Abstract [en]

    The adsorption of neutral (poly)-aromatic, antiaromatic, and more generally π-conjugated systems on graphene is studied as a prototypical case of π-π stacking. To account for dispersive interactions, we compare the recent van der Waals density functional (vdw-DF) with three semiempirical corrections to density functional theory and two empirical force fields. The adsorption energies of the molecules binding to graphene predicted by the vdw-DFwere found to be in excellent agreement with temperature desorption experiments reported in litera- ture,whereas the results of theremaining functionals andforce fields only preserve the correct trends. The comparison of the dispersive versus electrostatic contribu- tions to the total binding energies in the aromatic and antiaromatic systems suggests that π-π interactions can be regarded as being prevalently dispersive in nature at large separations, whereas close to the equilibrium bonding distance, it is a complex interplay between dispersive and electrostatic Coulombic interactions. Moreover our results surprisingly indicate that the magnitude of π-π interactions normalized both per number of total atoms and carbon atoms increases signifi- cantly with the relative number of hydrogen atoms in the studied systems.

  • 32.
    Björk, Jonas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Computational Physics. Linköping University, The Institute of Technology.
    Hanke, Felix
    Surface Science Research Centre, University of Liverpool, UK.
    Stafström, Sven
    Linköping University, Department of Physics, Chemistry and Biology, Computational Physics. Linköping University, The Institute of Technology.
    Mechanisms of halogen-based covalent self-assembly on metal surfaces2013In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 135, no 15, p. 5768-5775Article in journal (Refereed)
    Abstract [en]

    We computationally study the reaction mechanisms of halogen-based covalent self-assembly, a major route for synthesizing molecular nanostructures and nanographenes on surfaces. Focusing on biphenyl as a small model system, we describe the dehalogenation, recombination, and diffusion processes. The kinetics of the different processes are also investigated, in particular how diffusion and coupling barriers affect recombination rates. Trends across the periodic table are derived from three commonly used close-packed (111) surfaces (Cu, Ag, and Au) and two halogens (Br and I). We show that the halogen atoms can poison the surface, thus hindering long-range ordering of the self-assembled structures. Finally, we present core-level shifts of the relevant carbon and halogen atoms, to provide reference data for reliably detecting self-assembly without the need for atomic-resolution scanning tunneling microscopy.

  • 33.
    Björk, Jonas
    et al.
    University of Liverpool, UK.
    Matena, Manfred
    University of Basel, Switzerland.
    Dyer, Matthew S.
    University of Liverpool, UK.
    Enache, Mihaela
    University of Basel, Switzerland.
    Lobo-Checa, Jorge
    University of Basel, Switzerland.
    Gade, Lutz H.
    University of Heidelberg, Germany.
    Jung, Thomas A.
    Paul-Scherrer-Institute, Villigen, Switzerland.
    Stöhr, Meike
    University of Basel, Switzerland.
    Persson, Mats
    University of Liverpool, UK.
    STM fingerprint of molecule-adatom interactions in a self-assembled metal-organic surface coordination network on Cu(111)2010In: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 12, p. 8815-8821Article in journal (Refereed)
    Abstract [en]

    A novel approach of identifying metal atoms within a metal-organic surface coordination network using scanning tunnelling microscopy (STM) is presented. The Cu adatoms coordinated in the porous surface network of 1,3,8,10-tetraazaperopyrene (TAPP) molecules on a Cu(111) surface give rise to a characteristic electronic resonance in STM experiments. Using density functional theory calculations, we provide strong evidence that this resonance is a fingerprint of the interaction between the molecules and the Cu adatoms. We also show that the bonding of the Cu adatoms to the organic exodentate ligands is characterised by both the mixing of the nitrogen lone-pair orbitals of TAPP with states on the Cu adatoms and the partial filling of the lowest unoccupied molecular orbital (LUMO) of the TAPP molecule. Furthermore, the key interactions determining the surface unit cell of the network are discussed.

  • 34.
    Björk, Jonas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Computational Physics. Linköping University, The Institute of Technology.
    Stafström, Sven
    Linköping University, Department of Physics, Chemistry and Biology, Computational Physics. Linköping University, The Institute of Technology.
    Adsorption of large hydrocarbons on coinage metals: a van der Waals density functional study2014In: ChemPhysChem, ISSN 1439-4235, E-ISSN 1439-7641, Vol. 15, no 13, p. 2851-2858Article in journal (Refereed)
    Abstract [en]

    The adsorption of organic molecules onto the close-packed facets of coinage metals is studied, and how accurately adsorption heights can be described by using recent advances of the van der Waals density functional (vdWDF), with optPBE/vdWDF, optB86b/vdWDF, vdWDF2, and rev/vdWDF2 functionals is illustrated. The adsorption of two prototypical aromatic hydrocarbons is investigated, and the calculated adsorption heights are compared to experimental literature values from normal incident X-ray standing wave absorption and a state-of-the-art semi-empirical method. It is shown that both the optB86b/vdWDF and rev/vdWDF2 functionals describe adsorption heights with an accuracy of 0.1 Å, compared to experimental values, and are concluded as reliable methods of choice for related systems.

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  • 35.
    Björk, Jonas
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Computational Physics. Linköping University, The Institute of Technology.
    Zhang, Yi-Qi
    Technische Universität München, Garching, Germany.
    Klappenberger, Florian
    Technische Universität München, Garching, Germany.
    Barth, Johannes V.
    Technische Universität München, Garching, Germany.
    Stafström, Sven
    Linköping University, Department of Physics, Chemistry and Biology, Computational Physics. Linköping University, The Institute of Technology.
    Unraveling the Mechanism of the Covalent Coupling Between Terminal Alkynes on a Noble Metal2014In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 118, no 6, p. 3181-3187Article in journal (Refereed)
    Abstract [en]

    The mechanism of the newly reported route for surface-assisted covalent coupling of terminal alkynes on Ag(111) is unraveled by density functional theory based transition state calculations. We illustrate that the reaction path is fundamentally different from the classical coupling schemes in wet chemistry. It is initiated by the covalent coupling between two molecules instead of single-molecule dehydrogenation. The silver substrate is found to play an important role stabilizing the intermediate species by chemical bonds, although it is hardly active electronically in the actual coupling step. The dimer intermediate is concluded to undergo two subsequent dehydrogenation processes expected to be rate-limiting according to the comparatively large barriers, which origin is discussed.

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  • 36.
    Borga, Magnus
    et al.
    Linköping University, Department of Biomedical Engineering, Medical Informatics. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Dahlqvist, Leinhard Olof
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics.
    Lundberg, Peter
    Linköping University, Department of Medical and Health Sciences, Division of Radiological Sciences. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV). Östergötlands Läns Landsting, Center for Surgery, Orthopaedics and Cancer Treatment, Department of Radiation Physics.
    Improvement in Magnetic Resonance Imaging Relating to Correction of Chemical Shift Artifact and Intensity Inhomogeneity2011Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    Present invention discloses systems and methods for improvement of magnetic resonance images. Correction of a chemical shift artefact in an image acquired from a magnetic resonance imaging system is obtained by a system and a method involving iterative - compensation for the misregistration effect in an image domain. Correction of an intensity inhomogeneity in such images is obtained by a system and a method involving locating voxels corresponding to pure adipose tissue and estimating correction field from these points.

  • 37.
    Bounechada, Djamela
    et al.
    Chalmers Institute of Technology, Gothenburg.
    Darmastuti, Zhafira
    Linköping University, Department of Physics, Chemistry and Biology, Applied Sensor Science. Linköping University, The Institute of Technology.
    Ojamae, Lars
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, The Institute of Technology.
    Andersson, Mike
    Linköping University, Department of Physics, Chemistry and Biology, Applied Sensor Science. Linköping University, The Institute of Technology.
    Lloyd Spetz, Anita
    Linköping University, Department of Physics, Chemistry and Biology, Applied Sensor Science. Linköping University, The Institute of Technology.
    Skoglundh, Magnus
    Competence Centre for Catalysis / Department of Chemical and Biological Engineering, Chalmers University of Technology, Göteborg, Sweden.
    Carlsson, P-A
    Competence Centre for Catalysis / Department of Chemical and Biological Engineering, Chalmers University of Technology, Göteborg, Sweden.
    Vibrational analysis of SO2 on Pt / SiO2 systemManuscript (preprint) (Other academic)
    Abstract [en]

    In situ diffuse reflectance infrared Fourier transformed spectroscopy was used to study the interactions of SOx species with Pt/SiO2 between 200 and 400°C, and for SO2 concentrations between 10 and 50 ppm, which represents a concentration range where MISFET sensors exhibit good responses. In parallel, first-principles calculations have been carried out to support the experimental interpretations. It was found that sulfate species were formed on the silica surface, accompanied with removal/rearrangement of silanol groups upon exposure to SO2. Both experimental and theoretical calculations also suggest that the surface species were only formed after SO2 oxidation to SO3 on the metal surface. These evidences support the idea of SO2 oxidation to SO3 as the first step in the process of sulfate formation, followed by spillover of SO3 to the oxide, and finally the formation of sulfate species on the hydroxyl positions on the oxide. The results also indicate that the sulfate formation on silica depends both on the temperature and the SO2 concentration. Furthermore, hydrogen exposure was shown to be efficient for sulfur removal from the silica surface.

  • 38.
    Bronner, Christopher
    et al.
    Heidelberg Univ, Phys Chem Inst, D-69120 Heidelberg, Germany ; Free Univ Berlin, Fachbereich Phys, D-14195 Berlin, Germany.
    Björk, Jonas
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Chemistry. Linköping University, The Institute of Technology.
    Tegeder, Petra
    Heidelberg Univ, Phys Chem Inst, D-69120 Heidelberg, Germany ; Free Univ Berlin, Fachbereich Phys, D-14195 Berlin, Germany.
    Tracking and removing Br during the on-surface synthesis of a graphene nanoribbon2015In: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 119, no 1, p. 486-493Article in journal (Refereed)
    Abstract [en]

    The fabrication of graphene nanoribbons (GNRs) requires a high degree of precision due to the sensitivity of the electronic structure on the edge shape. Using Br-substituted molecular precursors, this atomic precision can be achieved in a thermally induced two-step reaction following Br dissociation on a Au(111) surface. Using DFT, we find evidence that the Br atoms are bound to the intermediate polyanthrylene chains. We employ temperature-programmed desorption to demonstrate the associative desorption of HBr and molecular hydrogen during the final cyclodehydrogenation step of the reaction. Both processes are found to have similar activation barriers. Furthermore, we are able to remove Br atoms from the polyanthrylene chains by providing molecular hydrogen. The subsequent formation of GNR via a cyclodehydrogenation demonstrates that Br does not influence this part of the overall reaction.

  • 39. Order onlineBuy this publication >>
    Bur, Christian
    Linköping University, Department of Physics, Chemistry and Biology, Applied Sensor Science. Linköping University, The Institute of Technology. Department of Physics and Mechatronics Engineering, Lab for Measurement Technology, Saarland University, Saarbrücken, Germany.
    Selectivity Enhancement of Gas Sensitive Field Effect Transistors by Dynamic Operation2015Doctoral thesis, monograph (Other academic)
    Abstract [en]

    Gas sensitive field effect transistors based on silicon carbide, SiC-FETs, have been applied to various applications mainly in the area of exhaust and combustion monitoring. So far, these sensors have normally been operated at constant temperatures and adaptations to specific applications have been done by material and transducer platform optimization.

    In this thesis, the methodology of dynamic operation for selectivity enhancement is systematically developed for SiC-FETs. Temperature cycling, which is well known for metal oxide gas sensors, is transferred to SiC-FETs. Additionally, gate bias modulation is introduced increasing the performance further.

    The multi-dimensional sensor data are evaluated by use of pattern recognition mainly based on multivariate statistics. Different strategies for feature selection, crossvalidation, and classification methods are studied.

    After developing the methodology of dynamic operation, i.e., applying the virtual multi-sensor approach on SiC-FETs, the concept is validated by two different case studies under laboratory conditions: Discrimination of typical exhaust gases and quantification of nitrogen oxides in a varying background is presented. Additionally, discrimination and quantification of volatile organic compounds in the low parts-perbillion range for indoor air quality applications is demonstrated. The selectivity of SiC-FETs is enhanced further by combining temperature and gate bias cycled operation. Stability is increased by extended training.

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  • 40.
    Burakovsky, L.
    et al.
    Los Alamos National Lab, NM 87545 USA.
    Cawkwell, M. J.
    Los Alamos National Lab, NM 87545 USA.
    Preston, D. L.
    Los Alamos National Lab, NM 87545 USA.
    Errandonea, D.
    University of Valencia, Spain.
    Simak, Sergey
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Physics. Linköping University, Faculty of Science & Engineering.
    Recent ab initio phase diagram studies: Iridium2017In: JOINT AIRAPT-25TH and EHPRG-53RD INTERNATIONAL CONFERENCE ON HIGH PRESSURE SCIENCE AND TECHNOLOGY, 2015, IOP PUBLISHING LTD , 2017, Vol. 950, article id UNSP 042021Conference paper (Refereed)
    Abstract [en]

    The phase diagram of iridium is investigated using the Z methodology in conjunction with the VASP ab initio molecular dynamics package. The Z methodology is a novel technique for phase diagram studies which combines the direct Z method for the computation of melting curves and the inverse Z method for the calculation of solid-solid phase boundaries. We compare our results to the available experimental data on iridium. We offer explanation for the 14-layer hexagonal structure observed in experiments by Cerenius and Dubrovinsky.

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  • 41.
    Busch, Christian
    et al.
    Applied Physical Chemistry, Institute for Physical Chemistry, Heidelberg University, Heidelberg, Germany.
    Nagy, Bela
    Linköping University, Department of Physics, Chemistry and Biology, Biophysics and bioengineering. Linköping University, Faculty of Science & Engineering.
    Stöcklin, Andreas
    Applied Physical Chemistry, Institute for Physical Chemistry, Heidelberg University, Heidelberg, Germany.
    Gutfreund, Philipp
    Institut Laue-Langevin, France.
    Dahint, Reiner
    Applied Physical Chemistry, Institute for Physical Chemistry, Heidelberg University, Heidelberg, Germany.
    Ederth, Thomas
    Linköping University, Department of Physics, Chemistry and Biology, Biophysics and bioengineering. Linköping University, Faculty of Science & Engineering.
    A mobile setup for simultaneous and in situ neutron reflectivity, infrared spectroscopy, and ellipsometry studies2022In: Review of Scientific Instruments, ISSN 0034-6748, E-ISSN 1089-7623, Vol. 93, no 11Article in journal (Refereed)
    Abstract [en]

    Neutron reflectivity at the solid/liquid interface offers unique opportunities for resolving the structure–function relationships of interfacial layers in soft matter science. It is a non-destructive technique for detailed analysis of layered structures on molecular length scales, providing thickness, density, roughness, and composition of individual layers or components of adsorbed films. However, there are also some well-known limitations of this method, such as the lack of chemical information, the difficulties in determining large layer thicknesses, and the limited time resolution. We have addressed these shortcomings by designing and implementing a portable sample environment for in situ characterization at neutron reflectometry beamlines, integrating infrared spectroscopy under attenuated total reflection for determination of molecular entities and their conformation, and spectroscopic ellipsometry for rapid and independent measurement of layer thicknesses and refractive indices. The utility of this combined setup is demonstrated by two projects investigating (a) pH-dependent swelling of polyelectrolyte layers and (b) the impact of nanoparticles on lipid membranes to identify potential mechanisms of nanotoxicity. 

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  • 42.
    Bushnell, Eric A. C.
    et al.
    Department of Chemistry and Biochemistry, University of Windsor, Windsor, ON, Canada.
    Erdtman, Edvin
    Örebro universitet, Akademin för naturvetenskap och teknik, Örebro Universitet, Örebro, Sweden.
    Llano, Jorge
    Department of Chemistry and Biochemistry, University of Windsor, Windsor, ON, Canada.
    Eriksson, Leif A.
    Örebro universitet, Akademin för naturvetenskap och teknik; School of Chemistry, National University of Ireland, Galway, Ireland.
    Gauld, James W.
    Department of Chemistry and Biochemistry, University of Windsor, Windsor, ON, Canada.
    The first branching point in porphyrin biosynthesis: a systematic docking, molecular dynamics and quantum mechanical/molecular mechanical study of substrate binding and mechanism of uroporphyrinogen-III decarboxylase2011In: Journal of Computational Chemistry, ISSN 0192-8651, E-ISSN 1096-987X, Vol. 32, no 5, p. 822-834Article in journal (Refereed)
    Abstract [en]

    In humans, uroporphyrinogen decarboxylase is intimately involved in the synthesis of heme, where the decarboxylation of the uroporphyrinogen-III occurs in a single catalytic site. Several variants of the mechanistic proposal exist; however, the exact mechanism is still debated. Thus, using an ONIOM quantum mechanical/molecular mechanical approach, the mechanism by which uroporphyrinogen decarboxylase decarboxylates ring D of uroporphyrinogen-III has been investigated. From the study performed, it was found that both Arg37 and Arg50 are essential in the decarboxylation of ring D, where experimentally both have been shown to be critical to the catalytic behavior of the enzyme. Overall, the reaction was found to have a barrier of 10.3 kcal mol−1 at 298.15 K. The rate-limiting step was found to be the initial protontransfer from Arg37 to the substrate before the decarboxylation. In addition, it has been found that several key interactions exist between the substrate carboxylate groups and backbone amides of various activesite residues as well as several other functional groups.

  • 43.
    Bäcklund, Fredrik
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Preparation and Application of Functionalized Protein Fibrils2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Many proteins have an innate ability to self-assemble into fibrous structures known as amyloid fibrils. From a material science perspective, fibrils have several interesting characteristics, including a high stability, a distinct shape and tunable surface properties. Such structures can be given additional properties through functionalization by other compounds such as fluorophores. Combination of fibrils with a function yielding compound can be achieved in several ways. Covalent bond attachment is specific, but cumbersome. External surface adhesion is nonspecific, but simple. However, in addition, internal non-covalent functionalization is possible. In this thesis, particular emphasis is put on internal functionalization of fibrils; by co-grinding fibril forming proteins with a hydrophobic molecule, a protein-hydrophobic compound molecule composite can be created that retains the proteins innate ability to form fibrils. Subsequently formed fibrils will thus have the structural properties of the protein fibril as well as the properties of the incorporated compound. The functionalization procedures used throughout this thesis are applicable for a wide range of chromophores commonly used for organic electronics and photonics. The methods developed and the prepared materials are useful for applications within optoelectronics as well as biomedicine.

    Regardless of the methodology of functionalization, using functionalized fibrils in a controlled fashion for material design requires an intimate understanding of the formation process and knowledge of the tools available to control not only the formation but also any subsequent macroscale assembly of fibrils. The development and application of such tools are described in several of the papers included in this thesis. With the required knowledge in hand, the possible influence of fibrils on the functionalizing agents, and vice versa, can be probed. The characteristic traits of the functionalized fibril can be customized and the resulting material can be organized and steered towards a specific shape and form. This thesis describes how control over the process of formation, functionalization and organization of functionalized fibrils can be utilized to influence the hierarchical assembly of fibrils – ranging from spherical structures to  spirals; the function – fluorescent or conducting; and macroscopic properties – optical birefringence and specific arrangement of functionalized fibrils in the solid state. In conclusion, the use of amyloid fibrils in material science has great potential. Herein is presented a possible route towards a fully bottom up approach ranging from the nanoscale to the macroscale.

    List of papers
    1. Controlling Amyloid Fibril Formation by Partial Stirring
    Open this publication in new window or tab >>Controlling Amyloid Fibril Formation by Partial Stirring
    2016 (English)In: Biopolymers, ISSN 0006-3525, E-ISSN 1097-0282, Vol. 105, no 5, p. 249-259Article in journal (Refereed) Published
    Abstract [en]

    Many proteins undergoes self-assembly into fibrillar structures known as amyloid fibrils. During the self-assembly process related structures, known as spherulites, can be formed. Herein we report a facile method where the balance between amyloid fibrils and spherulites can be controlled by stirring of the reaction mixture during the initial stages of the self-assembly process. Moreover, we report how this methodology can be used to prepare non-covalently functionalized amyloid fibrils. By stirring the reaction mixture continuously or for a limited time during the lag phase the fibril length, and hence the propensity to form liquid crystalline phases, can be influenced. This phenomena is utilized by preparing films consisting of aligned protein fibrils incorporating the laser dye Nile red. The resulting films display polarized Nile red fluorescence.

    Place, publisher, year, edition, pages
    Wiley-Blackwell, 2016
    National Category
    Organic Chemistry Biomaterials Science
    Identifiers
    urn:nbn:se:liu:diva-121017 (URN)10.1002/bip.22803 (DOI)000371690100001 ()
    Note

    Funding agencies:  Swedish Government [2009-00971]; Knut and Alice Wallenberg foundation

    Vid tiden för disputation förelåg publikationen endast som manuskript

    Available from: 2015-09-02 Created: 2015-09-02 Last updated: 2017-12-04Bibliographically approved
    2. Amyloid fibrils as dispersing agents for oligothiophenes: control of photophysical properties through nanoscale templating and flow induced fibril alignment
    Open this publication in new window or tab >>Amyloid fibrils as dispersing agents for oligothiophenes: control of photophysical properties through nanoscale templating and flow induced fibril alignment
    Show others...
    2014 (English)In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 2, no 37, p. 7811-7822Article in journal (Refereed) Published
    Abstract [en]

    Herein we report that protein fibrils formed from aggregated proteins, so called amyloid fibrils, serve as an excellent dispersing agent for hydrophobic oligothiophenes such as alpha-sexithiophene (6T). Furthermore, the protein fibrils are capable of orienting 6T along the fibril long axis, as demonstrated by flow-aligned linear dichroism spectroscopy and polarized fluorescence microscopy. The materials are prepared by solid state mixing of 6T with a protein capable of self-assembly. This results in a water soluble composite material that upon heating in aqueous acid undergoes self-assembly into protein fibrils non-covalently functionalized with 6T, with a typical diameter of 5-10 nm and lengths in the micrometre range. The resulting aqueous fibril dispersions are a readily available source of oligothiophenes that can be processed from aqueous solvent, and we demonstrate the fabrication of macroscopic structures consisting of aligned 6T functionalized protein fibrils. Due to the fibril induced ordering of 6T these structures exhibit polarized light emission.

    Place, publisher, year, edition, pages
    Royal Society of Chemistry, 2014
    National Category
    Biological Sciences
    Identifiers
    urn:nbn:se:liu:diva-111311 (URN)10.1039/c4tc00692e (DOI)000341458000013 ()
    Note

    Funding Agencies|Swedish Research Council [20114324]; Swedish Strategic Research Foundation (SSF); Knut and Alice Wallenberg foundation through a Wallenberg Scholar grant; Chalmers Area of Advance in Nanoscience and Nanotechnology; Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009-00971]

    Available from: 2014-10-14 Created: 2014-10-14 Last updated: 2017-12-05
    3. Development and Application of Methodology for Rapid Screening of Potential Amyloid Probes
    Open this publication in new window or tab >>Development and Application of Methodology for Rapid Screening of Potential Amyloid Probes
    2014 (English)In: ACS COMBINATORIAL SCIENCE, ISSN 2156-8952, Vol. 16, no 12, p. 721-729Article in journal (Refereed) Published
    Abstract [en]

    Herein, we demonstrate that it is possible to rapidly screen hydrophobic fluorescent aromatic molecules with regards to their properties as amyloid probes. By grinding the hydrophobic molecule with the amyloidogenic protein insulin, we obtained a water-soluble composite material. When this material is dissolved and exposed to conditions promoting amyloid formation, the protein aggregates into amyloid fibrils incorporating the hydrophobic molecule. As a result, changes in the fluorescence spectra of the hydrophobic molecule can be correlated to the formation of amyloid fibrils, and the suitability of the hydrophobic molecular skeleton as an amyloid probe can thus be assessed. As a result, we discovered two new amyloid probes, of which one is the well-known laser dye DCM. The grinding method can also be used for rapid preparation of novel composite materials between dyes and proteins, which can be used in materials science applications such as organic electronics and photonics.

    Place, publisher, year, edition, pages
    ACS Publications, 2014
    Keywords
    amyloid probes; rapid screening; fluorescent; aromatic molecules; laser dye DCM
    National Category
    Biological Sciences
    Identifiers
    urn:nbn:se:liu:diva-113169 (URN)10.1021/co5001212 (DOI)000346114600009 ()25383488 (PubMedID)
    Note

    Funding Agencies|Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University [2009-00971]; Knut and Alice Wallenberg Foundation

    Available from: 2015-01-14 Created: 2015-01-12 Last updated: 2015-09-02
    4. Tuning the aqueous self-assembly process of insulin by a hydrophobic additive
    Open this publication in new window or tab >>Tuning the aqueous self-assembly process of insulin by a hydrophobic additive
    2015 (English)In: RSC ADVANCES, ISSN 2046-2069, Vol. 5, no 112, p. 92254-92262Article in journal (Refereed) Published
    Abstract [en]

    Biomolecular self-assembly is an efficient way of preparing soft-matter based materials. Herein we report a novel method, based on the use of insoluble additives in aqueous media, for influencing the self-assembly process. Due to their low solubility, the use of hydrophobic additives in aqueous media is problematic; however, by mixing the additive with the biomolecule in the solid state, prior to solvation, this problem can be circumvented. In the investigated self-assembly system, where bovine insulin self-assembles into spherical structures, the inclusion of the hydrophobic material α-sexithiophene (6T) results in significant changes in the self-assembly process. Under our reaction conditions, in the case of materials prepared from insulin-only the growth of spherulites typically stops at a diameter of 150μm. However, by adding 2 weight % of hydrophobic material, spherulite growth continues up to diameters in the mm-range. The spherulites incorporate 6T and are thus fluorescent. The method reported herein should be of interest to all scientists working in the field of self-assembly as the flexible materials preparation, based simply on co-grinding of commercially available materials, adds another option to influence the structure and properties of products formed by  self-assembly reactions.

    Place, publisher, year, edition, pages
    Royal Society of Chemistry, 2015
    National Category
    Organic Chemistry Biomaterials Science
    Identifiers
    urn:nbn:se:liu:diva-121018 (URN)10.1039/c5ra16144d (DOI)000364032500040 ()
    Note

    Funding agencies: Swedish Government Strategic Research Area in Materials Science on Functional Materials at Linkoping University (Faculty Grant SFO-Mat-LiU) [2009-00971]; Knut and Alice Wallenberg foundation

    Available from: 2015-09-02 Created: 2015-09-02 Last updated: 2015-12-03
    5. Convection Induced Air-Water Interface Assembly of Amyloid Fibrils
    Open this publication in new window or tab >>Convection Induced Air-Water Interface Assembly of Amyloid Fibrils
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    We report that hydrophobically modified amyloid fibrils form macroscopic films at the air-water interface. The hydrophobically modified fibrils are prepared in a two step process. First bovine insulin is ground with a hydrophobic compound. The resulting material is dissolved in acidic water and heated to induce assembly into fibrils incorporating the hydrophobic compounds. Upon dilution followed by asymmetric heating, resulting in convection flow, the fibrills form highly ordered films with thicknesses from 80 nm and up. The thickness of the film can be controlled by the fibril concentration and/or reaction time. The films contain anisotropic domains spanning several square centimeters. In addition, the films contains ordered assemblies of dyes that display emission of polarized light.

    National Category
    Organic Chemistry Biomaterials Science
    Identifiers
    urn:nbn:se:liu:diva-121019 (URN)
    Available from: 2015-09-02 Created: 2015-09-02 Last updated: 2015-09-02
    6. Protein nanowires with conductive properties
    Open this publication in new window or tab >>Protein nanowires with conductive properties
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    2015 (English)In: Journal of Materials Chemistry C, ISSN 2050-7526, E-ISSN 2050-7534, Vol. 3, no 25, p. 6499-6504Article in journal (Refereed) Published
    Abstract [en]

    Herein we report on the investigation of self-assembled protein nanofibrils functionalized with metallic organic compounds. We have characterized the electronic behaviour of individual nanowires using conductive atomic force microscopy. In order to follow the self assembly process we have incorporated fluorescent molecules into the protein and used the energy transfer between the internalized dye and the metallic coating to probe the binding of the polyelectrolyte to the fibril.

    Place, publisher, year, edition, pages
    Royal Society of Chemistry, 2015
    National Category
    Biological Sciences
    Identifiers
    urn:nbn:se:liu:diva-120179 (URN)10.1039/c5tc00896d (DOI)000356529100010 ()
    Note

    Funding Agencies|Knut and Alice Wallenberg Foundation through a Wallenberg Scholar grant

    Available from: 2015-07-13 Created: 2015-07-13 Last updated: 2024-01-10
    7. PEDOT-S coated protein fibril microhelices
    Open this publication in new window or tab >>PEDOT-S coated protein fibril microhelices
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    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    We show here the preparation and characterization of micrometer sized conductive helices. We utilize protein fibrils as structural templates to create chiral helices with either right or left handed helicity. The helices are coated with the conductive polymer alkoxysulfonate poly(ethylenedioxythiophene) (PEDOT-S) to create micrometer sized conductive helices. The coating acts as a stabilizer for the template structure, facilitates the preparation of solid state films and shows significant conductivity. The helices have been investigated using Circular Dichroism (CD) and scanning electron microscopy (SEM) and the conductivity have been measured for solid state films.

    National Category
    Biochemistry and Molecular Biology
    Identifiers
    urn:nbn:se:liu:diva-121020 (URN)
    Available from: 2015-09-02 Created: 2015-09-02 Last updated: 2015-09-02Bibliographically approved
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  • 44.
    Börjesson, L.
    et al.
    Linköping University, Department of Neuroscience and Locomotion, Neurology. Linköping University, Faculty of Health Sciences.
    Stockhaus, J.
    Linköping University, Department of Neuroscience and Locomotion, Neurology. Linköping University, Faculty of Health Sciences.
    Gauffin, Helena
    Linköping University, Department of Neuroscience and Locomotion, Neurology. Linköping University, Faculty of Health Sciences. Östergötlands Läns Landsting, Local Health Care Services in Central Östergötland, Department of Neurology.
    Ragnehed, Mattias
    Linköping University, Department of Medicine and Care, Medical Radiology. Linköping University, Faculty of Health Sciences.
    Lundberg, Peter
    Linköping University, Department of Medicine and Care, Radiation Physics. Linköping University, Faculty of Health Sciences. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Söderfeldt, Birgitta
    Linköping University, Department of Neuroscience and Locomotion, Neurology. Linköping University, Faculty of Health Sciences.
    Comparison between fMRI and Wada test2004In: Epilepsia, ISSN 0013-9580, E-ISSN 1528-1167, Vol. 45, no Suppl. 3, p. 84-84Article in journal (Refereed)
    Abstract [en]

    Purpose: Language lateralisation in patients with epilepsy is more often atypical compared to a normal population. The Wada procedure for testing language and memory has some shortcomings; it is invasive and there is always a risk that the patient becomes too sedated, leading to difficulties in performing the tests. fMR1have shown promising results, showing good correlation to the Wadaprocedure concerning language-lateralisation. The aim of this studywas to investigate if fMRI could be used to determine which hemisphere was language dominant and compare the fMR1 results with the Wada-tests with a focus on patients with a complicated lateralisation.

    Method: 4 subjects were tested and they had a heterogeneous (I left handed, I ambidexter and 2 right handed) lateralisation and one had a severe dyslexia. A standard Wada procedure was used and compared with a fMRl investigation using a language paradigm.

    Results: The patients studied showed different language lateralisation patterns (2 left hemisphere and 2 bilateral). In two patients the two tests were fully concordant, in the others the fMRI showed a more bilateral pattern.

    Conclusion: fMR1 adds valuable information in the pre-surgical investigation for patients with a complex language lateralisation.

  • 45.
    Cai, Yunhao
    et al.
    Beihang Univ, Peoples R China.
    Zhang, Huotian
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Ye, Linglong
    Beihang Univ, Peoples R China.
    Zhang, Rui
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Xu, Jinqiu
    Shanghai Jiao Tong Univ, Peoples R China.
    Zhang, Kangning
    Shandong Univ, Peoples R China.
    Bi, Pengqing
    Shandong Univ, Peoples R China.
    Li, Tengfei
    Peking Univ, Peoples R China.
    Weng, Kangkang
    Beihang Univ, Peoples R China.
    Xu, Ke
    Wuhan Univ Technol, Peoples R China.
    Xia, Jianlong
    Wuhan Univ Technol, Peoples R China.
    Bao, Qinye
    East China Normal Univ, Peoples R China.
    Liu, Feng
    Shanghai Jiao Tong Univ, Peoples R China.
    Hao, Xiaotao
    Shandong Univ, Peoples R China.
    Tan, Songting
    Xiangtan Univ, Peoples R China.
    Gao, Feng
    Linköping University, Department of Physics, Chemistry and Biology, Biomolecular and Organic Electronics. Linköping University, Faculty of Science & Engineering.
    Zhan, Xiaowei
    Peking Univ, Peoples R China.
    Sun, Yanming
    Beihang Univ, Peoples R China.
    Effect of the Energy Offset on the Charge Dynamics in Nonfullerene Organic Solar Cells2020In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 12, no 39, p. 43984-43991Article in journal (Refereed)
    Abstract [en]

    The energy offset, considered as the driving force for charge transfer between organic molecules, has significant effects on both charge separation and charge recombination in organic solar cells. Herein, we designed material systems with gradually shifting energy offsets, including both positive and negative values. Time-resolved spectroscopy was used to monitor the charge dynamics within the bulk heterojunction. It is striking to find that there is still charge transfer and charge generation when the energy offset reached -0.10 eV (ultraviolet photoelectron spectroscopy data). This work not only indicates the feasibility of the free carrier generation and the following charge separation under the condition of a negative offset but also elucidates the relationship between the charge transfer and the energy offset in the case of polymer chlorination.

  • 46.
    Cao, Danfeng
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Sensor and Actuator Systems. Linköping University, Faculty of Science & Engineering.
    Martinez, Jose Gabriel
    Linköping University, Department of Physics, Chemistry and Biology, Sensor and Actuator Systems. Linköping University, Faculty of Science & Engineering.
    Hara, Emilio Satoshi
    Department of Biomaterials Graduate School of Medicine, Dentistry and Pharmaceutical Sciences,Okayama University, Japan.
    Jager, Edwin
    Linköping University, Department of Physics, Chemistry and Biology, Sensor and Actuator Systems. Linköping University, Faculty of Science & Engineering.
    Biohybrid Variable-Stiffness Soft Actuators that Self-Create Bone2022In: International conference on Electromechanically Active Polymer(EAP) transducers & artificial muscles, Tuscany, June 7-9, 2022, EuroEAP 2022 , 2022, article id 1.3.7Conference paper (Other (popular science, discussion, etc.))
    Abstract [en]

    We herein describe the fabrication, optimisation and characterisation of a biohybrid variable stiffness actuator that creates its own bone. By combining the electroresponsive properties of polypyrrole (PPy) with the compliant response of alginate gels functionalised with cell-derived plasma membrane nanofragments (PMNFs) it was possible to obtain bio-induced variable stiffness actuators. When the PMNFs were incubated into MEM, i.e. exposure to Ca, this caused the formation of calcium-phosphate minerals (i.e. amorphous calcium phosphate and hydroxyapatite) in the alginate gel, resulting in a more rigid layer and thus reducing and finally impeding the movement of the actuator, locking it in a fixed position within only 2 days. These actuators could morph in various, pre-programmed shapes and change their properties from soft to rigid. Adding different patterns to the actuator allowed locking the device in a predetermined shape without energy consumption, facilitating its application as soft-to-hard robotics as a biohybrid variant of so-called 4D manufacturing. The devices could wrap around and integrate into bone by the induced mineralisation in and on the gel layer. This illustrates its use as a potential tool to repair bone or in bone tissue engineering. 

  • 47.
    Cao, Danfeng
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Sensor and Actuator Systems. Linköping University, Faculty of Science & Engineering.
    Martinez, Jose Gabriel
    Linköping University, Department of Physics, Chemistry and Biology, Sensor and Actuator Systems. Linköping University, Faculty of Science & Engineering.
    Hara, Emilio Satoshi
    Department of Biomaterials, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.
    Jager, Edwin
    Linköping University, Department of Physics, Chemistry and Biology, Sensor and Actuator Systems. Linköping University, Faculty of Science & Engineering.
    Biohybrid Variable-Stiffness Soft Actuators that Self-Create Bone2022In: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 34, no 8, article id 2107345Article in journal (Refereed)
    Abstract [en]

    Inspired by the dynamic process of initial bone development, in which a soft tissue turns into a solid load-bearing structure, the fabrication, optimization, and characterization of bioinduced variable-stiffness actuators that can morph in various shapes and change their properties from soft to rigid are hereby presented. Bilayer devices are prepared by combining the electromechanically active properties of polypyrrole with the compliant behavior of alginate gels that are uniquely functionalized with cell-derived plasma membrane nanofragments (PMNFs), previously shown to mineralize within 2 days, which promotes the mineralization in the gel layer to achieve the soft to stiff change by growing their own bone. The mineralized actuator shows an evident frozen state compared to the movement before mineralization. Next, patterned devices show programmed directional and fixated morphing. These variable-stiffness devices can wrap around and, after the PMNF-induced mineralization in and on the gel layer, adhere and integrate onto bone tissue. The developed biohybrid variable-stiffness actuators can be used in soft (micro-)robotics and as potential tools for bone repair or bone tissue engineering.

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  • 48.
    Cao, Danfeng
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Sensor and Actuator Systems. Linköping University, Faculty of Science & Engineering.
    Martinez, Jose Gabriel
    Linköping University, Department of Physics, Chemistry and Biology, Sensor and Actuator Systems. Linköping University, Faculty of Science & Engineering.
    Hara, Emilio Satoshi
    Department of Biomaterials, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.
    Jager, Edwin W. H.
    Linköping University, Department of Physics, Chemistry and Biology, Sensor and Actuator Systems. Linköping University, Faculty of Science & Engineering.
    Soft actuators that self-create bone for biohybrid (micro)robotics2022In: Proceedings of The 5th International Conference on Manipulation, Automation, And Robotics at Small Scales (MARSS 2022), Institute of Electrical and Electronics Engineers (IEEE), 2022, p. 1-6Conference paper (Refereed)
    Abstract [en]

    Here we present a new class of variable stiffness actuators for soft robotics based on biohybrid materials that change their state from soft-to-hard by creating their own bones. The biohybrid variable stiffness soft actuators were fabricated by combining the electromechanically active polymer polypyrrole (PPy) with a soft substrate of polydimethylsiloxane or alginate gel. These actuators were functionalized with cell-derived plasma membrane nanofragments (PMNFs), which promote rapid mineralization within 2 days. These actuators were used in robotic devices, and PMNF mineralization resulted in the robotic devices to achieve a soft to stiff state change and thereby a decreased or stopped actuation. Moreover, perpendicularly and diagonally patterned actuators were prepared. The patterned actuators showed programmed directional actuation motion and could be fixated in this programmed state. Finally, patterned actuators that combined soft and rigid parts in one actuator showed more complex actuation motion. Together, these variable stiffness actuators could expand the range of applications of morphing robotics with more complex structures and functions. 

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    fulltext
  • 49.
    Cheung, Kitt
    et al.
    Linköping University, Department of Clinical and Experimental Medicine, Division of Cell Biology. Linköping University, Faculty of Medicine and Health Sciences.
    Lai, Kwok Kei
    Hong Kong Univ Sci and Technol, Peoples R China.
    Mak, Wing Cheung
    Linköping University, Department of Physics, Chemistry and Biology, Sensor and Actuator Systems. Linköping University, Faculty of Science & Engineering.
    Fabrication of Protein Microparticles and Microcapsules with Biomolecular Tools2018In: Zeitschrift fur physikalische Chemie (Munchen. 1991), ISSN 0942-9352, Vol. 232, no 5-6, p. 759-771Article in journal (Refereed)
    Abstract [en]

    Microparticles have attracted much attention for medical, analytical and biological applications. Calcium carbonate (CaCO3) templating method with the advantages of having narrow size distribution, controlled morphology and good biocompatibility that has been widely used for the synthesis of various protein-based microparticles. Despite CaCO3 template is biocompatible, most of the conventional methods to create stable protein microparticles are mainly driven by chemical crosslink reagents which may induce potential harmful effect and remains undesirable especially for biomedical or clinical applications. In this article, we demonstrate the fabrication of protein microparticles and microcapsules with an innovative method using biomolecular tools such as enzymes and affinity molecules to trigger the assembling of protein molecules within a porous CaCO3 template followed by a template removal step. We demonstrated the enzyme-assisted fabrication of collagen microparticles triggered by transglutaminase, as well as the affinity-assisted fabrication of BSA-biotin avidin microcapsules triggered by biotin-avidin affinity interaction, respectively. Based on the different protein assemble mechanisms, the collagen microparticles appeared as a solid-structured particles, while the BSA-biotin avidin microcapsules appeared as hollow-structured morphology. The fabrication procedures are simple and robust that allows producing protein microparticles or microcapsules under mild conditions at physiological pH and temperature. In addition, the microparticle morphologies, protein compositions and the assemble mechanisms were studied. Our technology provides a facile approach to design and fabricate protein microparticles and microcapsules that are useful in the area of biomaterials, pharmaceuticals and analytical chemistry.

  • 50.
    Cirera, Borja
    et al.
    IMDEA Nanoscience, c/Faraday 9, Cantoblanco,Madrid, Spain.
    Giménez-Agulló, Nelson
    Institute of Chemical Research of Catalonia, Barcelona Institute of Science and Technology, Avinguda Pa¨ısos Catalans 16, Tarragona, Spain.
    Björk, Jonas
    Linköping University, Department of Physics, Chemistry and Biology, Theoretical Chemistry. Linköping University, Faculty of Science & Engineering.
    Martínez-Peña, Francisco
    IMDEA Nanoscience, c/Faraday 9, Cantoblanco,Madrid, Spain..
    Martin-Jimenez, Alberto
    IMDEA Nanoscience, c/Faraday 9, Cantoblanco,Madrid, Spain..
    Rodriguez-Fernandez, Jonathan
    Departamento de F´ısica de la Materia Condensada, Universidad Auto´noma de Madrid, c/Francisco Toma´s y Valiente.
    Pizarro, Ana M.
    IMDEA Nanoscience, c/Faraday 9, Cantoblanco,Madrid, Spain..
    Otero, Roberto
    IMDEA Nanoscience, c/Faraday 9, Cantoblanco, 28049 Madrid, Spain,Universidad Auto´noma de Madrid, c/Francisco Toma´s y Valiente.
    Gallego, José M.
    Instituto de Ciencia de Materiales de Madrid, c/ Sor Juana Ine´s de la Cruz 3, Cantoblanco,Madrid, Spain..
    Ballester, Pablo
    Institute of Chemical Research of Catalonia, Barcelona Institute of Science and Technology, Avinguda Pa¨ısos Catalans 16, Tarragona, Spain/Catalan Institutionfor Research and Advanced Studies, Passeig Lluis Companys 23, Barcelona, Spain..
    Galan-Mascaros, José R.
    Institute of Chemical Research of Catalonia, Barcelona Institute of Science and Technology, Avinguda Pa¨ısos Catalans 16, Tarragona, Spain/Catalan Institutionfor Research and Advanced Studies, Passeig Lluis Companys 23, Barcelona, Spain..
    Ecija, David
    IMDEA Nanoscience, c/Faraday 9, Cantoblanco, Madrid, Spain.
    Thermal selectivity of intermolecular versus intramolecular reactions on surfaces2016In: Nature Communications, E-ISSN 2041-1723, Vol. 7, no 11002Article in journal (Refereed)
    Abstract [en]

    On-surface synthesis is a promising strategy for engineering heteroatomic covalent nanoarchitectures with prospects in electronics, optoelectronics and photovoltaics. Here we report the thermal tunability of reaction pathways of a molecular precursor in order to select intramolecular versus intermolecular reactions, yielding monomeric or polymeric phthalocyanine derivatives, respectively. Deposition of tetra-aza-porphyrin species bearing ethyl termini on Au(111) held at room temperature results in a close-packed assembly. Upon annealing from room temperature to 275 °C, the molecular precursors undergo a series of covalent reactions via their ethyl termini, giving rise to phthalocyanine tapes. However, deposition of the tetra-aza-porphyrin derivatives on Au(111) held at 300 °C results in the formation and self-assembly of monomeric phthalocyanines. A systematic scanning tunnelling microscopy study of reaction intermediates, combined with density functional calculations, suggests a [2+2] cycloaddition as responsible for the initial linkage between molecular precursors, whereas the monomeric reaction is rationalized as an electrocyclic ring closure.

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