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  • 301.
    Olsen, Peter
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Jawerth, Marcus
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Lawoko, Martin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Johansson, Mats
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Berglund, Lars
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Biokompositer. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Transforming technical lignins to structurally defined star-copolymers under ambient conditions2019Ingår i: Green Chemistry, ISSN 1463-9262, E-ISSN 1463-9270, Vol. 21, nr 9, s. 2478-2486Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Transforming biomass derived components to materials with controlled and predictable properties is a major challenge. Current work describes the controlled synthesis of starcopolymers with functional and degradable arms from the Lignoboost (R) process. Macromolecular control is achieved by combining lignin fractionation and characterization with ring-opening copolymerization (ROCP). The cyclic monomers used are epsilon-caprolactone (epsilon CL) and a functional carbonate monomer, 2-allyloxymethyl-2-ethyltrimethylene carbonate (AOMEC). The synthesis is performed at ambient temperature, under bulk conditions, in an open flask, and the graft composition and allyl functionality distribution are controlled by the copolymerization kinetics. Emphasis is placed on understanding the initiation efficiency, structural changes to the lignin backbone and the final macromolecular architecture. The present approach provides a green, scalable and cost effective protocol to create well-defined functional macromolecules from technical lignins.

  • 302.
    Ottenhall, Anna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Antimicrobial materials from cellulose using environmentally friendly techniques2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    Satsningen på ett mer biobaserat samhälle, där vi ersätter icke-förnybara material med förnyelsebara alternativ, är en pusselbit för en mer hållbar framtid samtidigt som den medför nya utmaningar. En viktig uppgift är att minska och kontrollera mikrobiell tillväxt, både för att skydda material från biologisk nedbrytning men också för att förhindra spridning av infektioner och toxiner.

    Cellulosabaserade material har behandlats med miljövänliga alternativ till traditionella biocider för att förhindra mikrobiell tillväxt och för ta bort bakterier från vatten. Två typer av antimikrobiella system har använts varefter den antimikrobiella effekten mot både mögel och bakterier utvärderats, med hjälp av både modellorganismer och mikrobiella odlingar från naturen.

    Den första typen av antimikrobiell metod som använts baseras på en kontakt-aktivt teknik. Cellulosafibrer har modifierats genom lager-på-lager polyelektrolytadsorption för att skapa en positiv ytladdning som kan attrahera och binda bakterier till fiberytan. Studien visar att modifierade pappersfilter, med porer som är mycket större än bakterier, kan filtrera bort mer än 99,9 % av E. coli från kontaminerat vatten. De polyelektrolyt-modifierade cellulosamaterialen påvisade goda antibakteriella egenskaper men förhindrade inte tillväxt av mögel.

    Den andra metoden som undersökts var att tillsätta biobaserade ämnen med antimikrobiella egenskaper till cellulosabaserade fiberskum. Kitosan och extraktivämnen från björkbark valdes ut som miljövänliga alternativ till vanliga biocider. Två typer av cellulosabaserade fiberskum har tagits fram och utvärderats för deras antimikrobiella egenskaper.

    Avhandlingen visar hur viktigt det är att veta hur materialet är tänkt att användas och vilken typ av mikroorganism som skall undvikas när man väljer antimikrobiell behandling av biobaserade material. God förståelse för både materialvetenskap och mikrobiologi är nödvändig när nya biobaserade material med antimikrobiella egenskaper skall designas.

  • 303.
    Ottenhall, Anna
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Henschen, Jonatan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Illergård, Josefin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Ek, Monica
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Cellulose-based water purification using paper filters modified with polyelectrolyte multilayers to remove bacteria from water through electrostatic interactions2018Ingår i: Environmental Science: Water Research & Technology, ISSN 20531400Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Filtration is a common way to obtain pure drinking water by removing particles and microorganisms based on size exclusion. Cellulose-based filters are affordable and biobased option for the removal of particles but bacteria are usually too small to be removed by size exclusion alone. In this article, the surfaces of cellulose fibres in two types of commercial paper filters have been given a positive net charge to trap bacteria through electrostatic interactions without releasing any biocides. The fibres were modified with the cationic polyelectrolyte polyvinylamine polymer in single layers (1 L) or in multilayers together with the anionic polyelectrolyte polyacrylic acid (3 L or 5 L) using a water-based process at room temperature. Filtration tests show that all filters, using both types of filter papers and a number of layers, can physically remove more than 99.9% of E. coli from water and that the 3 L modified filters can remove more than 97% of cultivatable bacteria from natural water samples. The bacterial reduction increased with increasing number of filter sheets used for the filtration and the majority of the bacteria were trapped in the top sheets of the filter. The results show the potential for creating water purification filters from bio-based everyday consumable products with a simple modification process. The filters could be used in the future for point-of-use water purification that may be able to save lives without releasing bactericides.

  • 304.
    Ottenhall, Anna
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Illergård, Josefin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Ek, Monica
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Water Purification Using Functionalized Cellulosic Fibers with Nonleaching Bacteria Adsorbing Properties2017Ingår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 51, s. 7616-7623Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Portable purification systems are easy ways to obtain clean drinking water when there is no large-scale water treatment available. In this study, the potential to purify water using bacteria adsorbing cellulosic fibers, functionalized with polyelectrolytes according to the layer-by-layer method, is investigated. The adsorbed polyelectrolytes create a positive charge on the fiber surface that physically attracts and bonds with bacteria. Three types of cellulosic materials have been modified and tested for the bacterial removal capacity in water. The time, material-water ratio and bacterial concentration dependence, as well as the bacterial removal capacity in water from natural sources, have been evaluated. Freely dispersed bacteria adsorbing cellulosic fibers can remove greater than 99.9% of Escherichia coli from nonturbid water, with the most notable reduction occurring within the first hour. A filtering approach using modified cellulosic fibers is desirable for purification of natural water. An initial filtration test showed that polyelectrolyte multilayer modified cellulosic fibers can remove greater than 99% of bacteria from natural water. The bacteria adsorbing cellulosic fibers do not leach any biocides, and it is an environmentally sustainable and cheap option for disposable water purification devices.

  • 305.
    Ottenhall, Anna
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Träkemi och massateknologi.
    Seppänen, Tiinamari
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Ek, Monica
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Water-stable cellulose fiber foam with antimicrobial properties for bio based low-density materials2016Ingår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 5, s. 2599-2613Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    New bio-based packaging materials are highly interesting for replacing conventional fossil based products for a more sustainable society. Water-stable cellulose fiber foams have been produced in a simple one-batch foam-forming process with drying under ambient conditions. The cellulose fiber foams have a low density (33–66 kg/m3) and can inhibit microbial growth; two highly valuable features for insulating packaging materials, especially in combination with stability in water. Cationic chitosan and/or polyvinylamine have been added during the foam-forming process to give the foams water-stability and antimicrobial properties. The structural and mechanical properties of the cellulose fiber foams have been studied and the antimicrobial properties have been evaluated with respect to both Escherichia coli, a common model bacteria and Aspergillus brasiliensis, a sporulating mold. The cellulose foams containing chitosan had both good water-stability and good antibacterial and antifungal properties, while the foams containing PVAm did disintegrate in water and did not inhibit fungal growth when nutrients were added to the foam, showing that it is possible to produce a bio-based foam material with the desired characters. This can be an interesting low-density packaging material for protection from both mechanical and microbial damage without using any toxic compounds.

  • 306.
    Ottenhall, Anna
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Seppänen, Tiinamari
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Ek, Monica
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Water-stable cellulose fiber foam with antimicrobial properties for bio based low-density materials2018Ingår i: Cellulose (London), ISSN 0969-0239, E-ISSN 1572-882X, Vol. 25, nr 4, s. 2599-2613Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    New bio-based packaging materials are highly interesting for replacing conventional fossil based products for a more sustainable society. Water-stable cellulose fiber foams have been produced in a simple one-batch foam-forming process with drying under ambient conditions. The cellulose fiber foams have a low density (33–66 kg/m3) and can inhibit microbial growth; two highly valuable features for insulating packaging materials, especially in combination with stability in water. Cationic chitosan and/or polyvinylamine have been added during the foam-forming process to give the foams water-stability and antimicrobial properties. The structural and mechanical properties of the cellulose fiber foams have been studied and the antimicrobial properties have been evaluated with respect to both Escherichia coli, a common model bacteria and Aspergillus brasiliensis, a sporulating mold. The cellulose foams containing chitosan had both good water-stability and good antibacterial and antifungal properties, while the foams containing PVAm did disintegrate in water and did not inhibit fungal growth when nutrients were added to the foam, showing that it is possible to produce a bio-based foam material with the desired characters. This can be an interesting low-density packaging material for protection from both mechanical and microbial damage without using any toxic compounds.

  • 307.
    Ouyang, Liangqi
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Fiberteknologi. Linkoping Univ, IFM, Linkoping, Sweden..
    Elfwing, Anders
    Linkoping Univ, IFM, Linkoping, Sweden..
    Ponseca, Carlito
    Linkoping Univ, IFM, Linkoping, Sweden..
    Cai, Wanzhu
    Linkoping Univ, IFM, Linkoping, Sweden..
    Inganas, Olle
    Linkoping Univ, IFM, Linkoping, Sweden..
    Decorating biomolecules and bio-structures with metallic conducting polymers2018Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 256Artikel i tidskrift (Övrigt vetenskapligt)
  • 308.
    Ozeren, Husamettin Deniz
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Nilsson, Fritjof
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Olsson, Richard
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Hedenqvist, Mikael S.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Prediction of plasticization mechanisms for biobased plastics through a combined experimental and molecular dynamics simulations approach2018Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 256Artikel i tidskrift (Övrigt vetenskapligt)
  • 309.
    Panzer, Matthew B.
    et al.
    Univ Virginia, Ctr Appl Biomech, Charlottesville, VA USA..
    Giudice, J. Sebastian
    Univ Virginia, Ctr Appl Biomech, Charlottesville, VA USA..
    Caudillo, Adrian
    Univ Virginia, Ctr Appl Biomech, Charlottesville, VA USA..
    Mukherjee, Sayak
    Univ Virginia, Ctr Appl Biomech, Charlottesville, VA USA..
    Kong, Kevin
    Univ Virginia, Ctr Appl Biomech, Charlottesville, VA USA..
    Cronin, Duane S.
    Univ Waterloo, Waterloo, ON, Canada..
    Barker, Jeffrey
    Univ Waterloo, Waterloo, ON, Canada..
    Gierczycka, Donata
    Univ Waterloo, Waterloo, ON, Canada..
    Bustamante, Michael
    Univ Waterloo, Waterloo, ON, Canada..
    Bruneau, David
    Univ Waterloo, Waterloo, ON, Canada..
    Corrales, Miguel
    Univ Waterloo, Waterloo, ON, Canada..
    Halldin, Peter
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Neuronik. KTH Royal Inst Technol, Stockholm, Sweden..
    Fahlstedt, Madelen
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Medicinteknik och hälsosystem, Neuronik.
    Arnesen, Marcus
    Jungstedt, Erik
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Biokompositer. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Gayzik, F. Scott
    Wake Forest Univ, Bowman Gray Sch Med, Winston Salem, NC USA..
    Stitzel, Joel D.
    Wake Forest Univ, Bowman Gray Sch Med, Winston Salem, NC USA..
    Decker, William
    Wake Forest Univ, Bowman Gray Sch Med, Winston Salem, NC USA..
    Baker, Alex M.
    Wake Forest Univ, Bowman Gray Sch Med, Winston Salem, NC USA..
    Ye, Xin
    Wake Forest Univ, Bowman Gray Sch Med, Winston Salem, NC USA..
    Brown, Philip
    Wake Forest Univ, Bowman Gray Sch Med, Winston Salem, NC USA..
    NUMERICAL CROWDSOURCING OF NFL FOOTBALL HELMETS2018Ingår i: Journal of Neurotrauma, ISSN 0897-7151, E-ISSN 1557-9042, Vol. 35, nr 16, s. A148-A148Artikel i tidskrift (Övrigt vetenskapligt)
  • 310.
    Pappalardo, Daniela
    et al.
    Univ Sannio, Dept Sci & Technol, Via Mulini, I-82100 Benevento, Italy..
    Mathisen, Torbjorn
    Novus Sci AB, Virdings Alle 2, S-75450 Uppsala, Sweden..
    Finne Wistrand, Anna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Biocompatibility of Resorbable Polymers: A Historical Perspective and Framework for the Future2019Ingår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 20, nr 4, s. 1465-1477Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The history of resorbable polymers containing glycolide, lactide, e-caprolactone and trimethylene carbonate, with a special emphasis being placed on the time frame of the 1960s-1990s is described. Reviewing the history is valuable when looking into the future perspectives regarding how and where these monomers should be used. This story includes scientific evaluations indicating that these polymers are safe to use in medical devices, while the design of the medical device is not considered in this report. In particular, we present the data regarding the tissue response to implanted polymers, as well as the toxicity and pharmacokinetics of their degradation products. In the translation of these polymers from "the bench to the bedside," various challenges have been faced by surgeons, medical doctors, biologists, material engineers and polymer chemists. This Perspective highlights the visionary role played by the pioneers, addressing the problems that occurred on a case by case basis in translational medicine.

  • 311.
    Paulraj, T.
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Riazanova, A. V.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Svagan, A. J.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center. KTH Royal Inst Technol, Wallenberg Wood Sci Ctr, SE-10044 Stockholm, Sweden. KTH Royal Inst Technol, Dept Fiber & Polymer Technol, SE-10044 Stockholm, Sweden..
    Bioinspired capsules based on nanocellulose, xyloglucan and pectin - The influence of capsule wall composition on permeability properties2018Ingår i: Acta Biomaterialia, ISSN 1742-7061, E-ISSN 1878-7568, Vol. 69, s. 196-205Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Materials based on renewable biopolymers, selective permeability and stimuli-responsive release/loading properties play an important role in biomedical applications. Here, in order to mimic the plant primary cell-wall, microcapsules have been fabricated using cell wall polysaccharides, namely pectin, xyloglucan and cellulose nanofibers. For the first time, a large amount of xyloglucan was successfully included in such capsules. These capsules demonstrated stimuli-responsive (ON/OFF) permeability and biocompatibility. The live cell staining revealed that the microcapsules' surface enhanced cell growth and also the non-toxic nature of the microcapsules. In water, the microcapsules were completely and partially permeable to fluorescent dextrans with an average molecular weight of 70 kDa (hydrodynamic diameter of ca. 12 nm) and 2000 kDa (ca. 54 nm), respectively. On the other hand, the permeability dropped quickly when the capsules were exposed to 250 mM NaCl solution, trapping a fraction of the 70 kDa dextrans in the capsule interior. The decrease in permeability was a direct consequence of the capsule-wall composition, i.e. the presence of xyloglucan and a low amount of charged molecules such as pectin. The low permeability of capsules in saline conditions (and in a model biological medium), combined with a capsule wall that is made from dietary fibers only, potentially enables their use in biological applications, such as colon targeted delivery in the gastro-intestinal tract. 

  • 312.
    Paulraj, Thomas
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Crespo, Gaston
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi.
    Svagan, Anna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Cage-like cellulose nanofiber-based microcapsules for electrochemical and biosensor applications2018Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 256Artikel i tidskrift (Övrigt vetenskapligt)
  • 313.
    Paulraj, Thomas
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Svagan, Anna Justina
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Bioinspired capsules based on nanocellulose, xyloglucan and pectin for biomedical applications2018Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 255Artikel i tidskrift (Övrigt vetenskapligt)
  • 314.
    Paulraj, Thomas
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Wennmalm, Stefan
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Experimentell biomolekylär fysik. KTH, Centra, Science for Life Laboratory, SciLifeLab. ..
    Riazanova, Anastasia, V
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Wu, Qiong
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Crespo, Gaston A.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Tillämpad fysikalisk kemi.
    Svagan, Anna J.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Porous Cellulose Nanofiber-Based Microcapsules for Biomolecular Sensing2018Ingår i: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 10, nr 48, s. 41146-41154Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Cellulose nanofibers (CNFs) have recently attracted a lot of attention in sensing because of their multifunctional character and properties such as renewability, nontoxicity, biodegradability, printability, and optical transparency in addition to unique physicochemical, barrier, and mechanical properties. However, the focus has exclusively been devoted toward developing two-dimensional sensing platforms in the form of nanopaper or nanocellulose-based hydrogels. To improve the flexibility and sensing performance in situ, for example, to detect biomarkers in vivo for early disease diagnostics, more advanced CNF-based structures are needed. Here, we developed porous and hollow, yet robust, CNF-based microcapsules using only the primary plant cell wall components, CNF, pectin, and xyloglucan, to assemble the capsule wall. The fluorescein isothiocyanate-labeled dextrans with M-w of 70 and 2000 kDa could enter the hollow capsules at a rate of 0.13 +/- 0.04 and 0.014 +/- 0.009 s(-1), respectively. This property is very attractive because it minimizes the influence of mass transport through the capsule wall on the response time. As a proof of concept, glucose oxidase (GOx) enzyme was loaded (and cross-linked) in the microcapsule interior with an encapsulation efficiency of 68 +/- 2%. The GOx-loaded microcapsules were immobilized on a variety of surfaces (here, inside a flow channel, on a carbon-coated sensor or a graphite rod) and glucose concentrations up to 10 mM could successfully be measured. The present concept offers new opportunities in the development of simple, more efficient, and disposable nanocellulose-based analytical devices for several sensing applications including environmental monitoring, healthcare, and diagnostics.

  • 315. Pavlidis, I. V.
    et al.
    Hendrikse, Natalie
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Syrén, Per-Olof
    KTH, Centra, Science for Life Laboratory, SciLifeLab.
    Chapter 5: Computational Techniques for Efficient Biocatalysis2018Ingår i: RSC Catalysis Series, nr 32, s. 119-152Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Addressing some of the most challenging problems that we face today, including depletion of natural resources, sustainable energy production and the generation of green polymeric materials by the biocatalytic upcycling of renewable synthons, requires an expansion of the current available biochemical reaction space. Creating biocatalysts harboring novel chemistries - whether inside or outside the cell - is dependent on the discovery of novel enzymes and metabolic pathways, together with the de novo design of enzymes and directed evolution. Herein we review the high potential of using bioinformatics and in silico computer modelling tools to guide protein engineering and to enhance our fundamental understanding of biocatalysis. Following an overview of technical considerations and the current state-of-the art in sequence- and structure-based protein engineering methodologies, we highlight recent successful examples of their implementation in biocatalysis and synthetic biology. Moreover, we discuss how selected computational tools in concert with experimental biocatalysis could decipher how the sequence, structure and dynamics of proteins dictate their function. Using the methodologies discussed in this chapter, an accelerated biocatalytic manufacturing of chemicals, pharmaceuticals, biofuels and monomeric building blocks is envisioned.

  • 316.
    Pendergraph, Samuel A.
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Klein, Gregor
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH Royal Inst Technol, Stockholm, Sweden..
    Johansson, Mats
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH Royal Inst Technol, Stockholm, Sweden..
    Carlmark, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH Royal Inst Technol, Stockholm, Sweden..
    Surface-initiated ring opening polymerization of carbonates and siloxanes from cellulose surfaces2015Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 249Artikel i tidskrift (Övrigt vetenskapligt)
  • 317.
    Percec, Simona
    et al.
    Temple Univ, Philadelphia, PA 19122 USA..
    Albertsson, Ann-Christine
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Rational Design of Multifunctional Renewable-Resourced Materials2019Ingår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 20, nr 2, s. 569-572Artikel i tidskrift (Refereegranskat)
  • 318.
    Petre, Daniela-Geta
    et al.
    Radboud Univ Nijmegen, Med Ctr, Dept Regenerat Biomat, Philips Leydenlaan 25, NL-6525 EX Nijmegen, Netherlands..
    Kucko, Nathan W.
    Radboud Univ Nijmegen, Med Ctr, Dept Regenerat Biomat, Philips Leydenlaan 25, NL-6525 EX Nijmegen, Netherlands.;CAM Bioceram BV, Zernikedreef 6, NL-2333 CL Leiden, Netherlands..
    Abbadessa, Anna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. Univ Utrecht, Fac Sci, UIPS, Dept Pharmaceut, NL-3508 TB Utrecht, Netherlands..
    Vermonden, Tina
    Univ Utrecht, Fac Sci, UIPS, Dept Pharmaceut, NL-3508 TB Utrecht, Netherlands..
    Polini, Alessandro
    Radboud Univ Nijmegen, Med Ctr, Dept Regenerat Biomat, Philips Leydenlaan 25, NL-6525 EX Nijmegen, Netherlands..
    Leeuwenburgh, Sander C. G.
    Radboud Univ Nijmegen, Med Ctr, Dept Regenerat Biomat, Philips Leydenlaan 25, NL-6525 EX Nijmegen, Netherlands..
    Surface functionalization of polylactic acid fibers with alendronate groups does not improve the mechanical properties of fiber-reinforced calcium phosphate cements2019Ingår i: Journal of The Mechanical Behavior of Biomedical Materials, ISSN 1751-6161, E-ISSN 1878-0180, Vol. 90, s. 472-483Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Calcium phosphate cements (CPCs) are frequently used as synthetic bone substitute, but their intrinsic low fracture toughness impedes their application in highly loaded skeletal sites. However, fibers can be used to reduce the brittleness of these CPCs provided that the affinity between the fibers and cement matrix facilitates the transfer of loads from the matrix to the fibers. The aim of the present work was to improve the interface between hydrophobic polylactic acid (PLA) microfibers and hydrophilic CPC. To this end, calcium-binding alendronate groups were conjugated onto the surface of PLA microfibers via different strategies to immobilize a tunable amount of alendronate onto the fiber surface. CPCs reinforced with PLA fibers revealed toughness values which were up to 50-fold higher than unreinforced CPCs. Nevertheless, surface functionalization of PLA microfibers with alendronate groups did not improve the mechanical properties of fiber-reinforced CPCs.

  • 319.
    Petrou, Georgia
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Glykovetenskap.
    Jansson, Ronnie
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap, Protein Engineering.
    Hogqvist, Mark
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH).
    Erlandsson, Johan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Wågberg, Lars
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Hedhammar, My
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Proteinvetenskap, Proteinteknologi.
    Crouzier, Thomas
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Glykovetenskap.
    Genetically Engineered Mucoadhesive Spider Silk2018Ingår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 19, nr 8, s. 3268-3279Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Mucoadhesion is defined as the adhesion of a material to the mucus gel covering the mucous membranes. The mechanisms controlling mucoadhesion include nonspecific electrostatic interactions and specific interactions between the materials and the mucins, the heavily glycosylated proteins that form the mucus gel. Mucoadhesive materials can be used to develop mucosal wound dressings and noninvasive transmucosal drug delivery systems. Spider silk, which is strong, biocompatible, biodegradable, nontoxic, and lightweight would serve as an excellent base for the development of such materials. Here, we investigated two variants of the partial spider silk protein 4RepCT genetically engineered in order to functionalize them with mucoadhesive properties. The pLys-4RepCT variant was functionalized with six cationically charged lysines, aiming to provide nonspecific adhesion from electrostatic interactions with the anionically charged mucins, while the hGal3-4RepCT variant was genetically fused with the Human Galectin-3 Carbohydrate Recognition Domain which specifically binds the mucin glycans Gal beta 1-3GlcNAc and Gal beta 1-4GlcNAc. First, we demonstrated that coatings, fibers, meshes, and foams can be readily made from both silk variants. Measured by the adsorption of both bovine submaxillary mucin and pig gastric mucin, the newly produced silk materials showed enhanced mucin binding properties compared with materials of wild-type (4RepCT) silk. Moreover, we showed that pLys-4RepCT silk coatings bind mucins through electrostatic interactions, while hGal3-4RepCT silk coatings bind mucins through specific glycan-protein interactions. We envision that the two new mucoadhesive silk variants pLys-4RepCT and hGal3-4RepCT, alone or combined with other biofunctional silk proteins, constitute useful new building blocks for a range of silk protein-based materials for mucosal treatments.

  • 320.
    Pettersson, Torbjörn
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Erlandsson, Johan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Larsson, Per
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH Royal Inst Technol, Fibre & Polymer Technol, Stockholm, Sweden..
    Wågberg, Lars
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    On the mechanism of freeze-induced crosslinking of aerogels made from periodate-oxidised cellulose nanofibrils2018Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 255Artikel i tidskrift (Övrigt vetenskapligt)
  • 321.
    Pettersson, Torbjörn
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Pendergraph, Samuel A.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Utsel, Simon
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. KTH Royal Inst Technol, Fibre & Polymer Technol, Stockholm, Sweden..
    Marais, Andrew
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Gustafsson, Emil
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Wågberg, Lars
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Robust and tailored wet adhesion in biopolymer thin film with wet adhesion and toughness superior to wet adhesion in bone2015Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 249Artikel i tidskrift (Övrigt vetenskapligt)
  • 322. Piri, Imelda Saran
    et al.
    Das, Oisik
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Hedenqvist, Mikael S.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Vaisanen, Taneli
    Ikram, Shafaq
    Bhattacharyya, Debes
    Imparting resiliency in biocomposite production systems: A system dynamics approach2018Ingår i: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 179, s. 450-459Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A biocomposite production system (BPS) contains a wide range of elements that are vulnerable to internal as well as external factors that may stimulate a system to be disrupted. Hence, there is a need to manifest resiliency in order to withstand the inevitable change without affecting its robustness and stability. The three aspects of a resilient BPS are interconnectivity, adaptability and transformability. The interconnectivity concept deals with the reliability and effectiveness of the supply chain network and production systems' resourcefulness. The adaptability aspect reinforces the agility and adjusting capacity of a system towards versatility and flexibility across the range of elements involved in the production system. Transformability deals with the capacity of a system to alter into a new system based on research, innovation and creativity. Therefore, the core aspects of resiliency in a BPS would result in increased stability and effectiveness. System dynamics models have been developed depicting the cause and effect of each of the three aspects. Finally, a model has been presented which could enable researchers and organizations to take guided decision towards a more robust and resilient BPS.

  • 323. Podkościelna, B.
    et al.
    Gordobil, O.
    Riazanova, Anastasiia
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Dobele, G.
    Labidi, J.
    Lindström, Mikael
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Gun'ko, V. M.
    Sevastyanova, Olena
    Novel Porous Materials Obtained from Technical Lignins and Their Methacrylate Derivatives Copolymerized with Styrene and Divinylbenzene2017Ingår i: ChemistrySelect, ISSN 2365-6549, Vol. 2, nr 7, s. 2257-2264Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The increasing availability of various types of technical lignins as result of the emergence of new biorefinery technologies has boosted the interest in the commercialization of lignin-based materials. Here we suggest a novel method for the preparation of uniform porous microspheres through emulsion-suspension polymerization of various technical lignins and related methacrylates with styrene (St) and divinylbenzene (DVB). Obtained microspheres have diameters in the range of 5–50 μm, with a more uniform shape for copolymers that contains lignin derivatives. Nitrogen sorption with DFT theory indicates that the microspheres are mesoporous materials with specific surface areas in the range of 230–270 m2g−1 but with significant differences in pore volume, especially in the mesopores size range (0–0.65 cm3g−1). Theoretical modeling of lignin alone and in St-DVB composites shows changes in polarity of the structures, which have become mosaics with hydrophilic and hydrophobic functionalities. This structure affects the properties of the interfacial water and, therefore, can affect the adsorption of both polar and nonpolar adsorbates in solid-phase extraction.

  • 324.
    Popov, Sergei
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik.
    Marinins, Aleksandrs
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Material- och nanofysik.
    Sychugov, Ilya
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Yan, Max
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik.
    Vasileva, Elena
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Fotonik.
    Li, Yuanyuan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Berglund, Lars
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Biokompositer.
    Udalcovs, Aleksejs
    RISE Acreo AB, Stockholm, Sweden..
    Ozolins, Oskars
    RISE Acreo AB, Stockholm, Sweden..
    Polymer photonics and nano-materials for optical communication2018Ingår i: 2018 17TH WORKSHOP ON INFORMATION OPTICS (WIO), Institute of Electrical and Electronics Engineers (IEEE), 2018Konferensbidrag (Refereegranskat)
    Abstract [en]

    Polymer materials offer process compatibility, design flexibility, and low cost technology as a multi-functional platform for optical communication and photonics applications. Design and thermal reflowing technology of low loss polymer waveguides, as well as demonstration of transparent wood laser are presented in this paper.

  • 325.
    Pourmand, Payam
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Kemi.
    Hedenqvist, Mikael S.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Furo, Istvan
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Kemi.
    Gedde, Ulf W
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Deterioration of highly filled EPDM rubber by thermal ageing in air: Kinetics and non-destructive monitoring2017Ingår i: Polymer testing, ISSN 0142-9418, E-ISSN 1873-2348, Vol. 64, s. 267-276Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The effects of air ageing at different temperatures between 110 and 170 degrees C on cable transit seals based on highly filled EPDM rubber used in nuclear power plants were studied. The changes of the macroscopic mechanical properties (Young's modulus, indentation modulus and strain-at-break) were in accordance with the Arrhenius equation with an activation energy of 110 kJ mol(-1). Profiling to assess the structure and property gradients within aged blocks was performed via IR spectroscopy, micro-indentation, gravimetric analysis of n-heptane-extracted samples and non-invasive portable NMR spectroscopy. A previously developed methodology was used to separate the deterioration into three different processes: polymer oxidation that was diffusion-limited at all temperatures, migration of low-molar-mass species to the surrounding media and anaerobic changes to the polymer network. The methodology allowed the assessment of the kinetics (rate as a function of time and temperature) of the different processes. It was noticed that polymer oxidation yielded more crosslinking at higher temperatures than at lower temperatures. The data obtained by both the portable NMR (a non-invasive method) and the indentation modulus profiling showed correlations with strain-at-break data, indicating their usefulness as condition monitoring methods.

  • 326.
    Pourrahimi, Amir Masoud
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Olsson, Richard
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymera material.
    Hedenqvist, Mikael S.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    The Role of Interfaces in Polyethylene/Metal-Oxide Nanocomposites for Ultrahigh-Voltage Insulating Materials2018Ingår i: Advanced Materials, ISSN 0935-9648, E-ISSN 1521-4095, Vol. 30, nr 4, artikel-id 1703624Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Recent progress in the development of polyethylene/metal-oxide nanocomposites for extruded high-voltage direct-current (HVDC) cables with ultrahigh electric insulation properties is presented. This is a promising technology with the potential of raising the upper voltage limit in today's underground/submarine cables, based on pristine polyethylene, to levels where the loss of energy during electric power transmission becomes low enough to ensure intercontinental electric power transmission. The development of HVDC insulating materials together with the impact of the interface between the particles and the polymer on the nanocomposites electric properties are shown. Important parameters from the atomic to the microlevel, such as interfacial chemistry, interfacial area, and degree of particle dispersion/aggregation, are discussed. This work is placed in perspective with important work by others, and suggested mechanisms for improved insulation using nanoparticles, such as increased charge trap density, adsorption of impurities/ions, and induced particle dipole moments are considered. The effects of the nanoparticles and of their interfacial structures on the mechanical properties and the implications of cavitation on the electric properties are also discussed. Although the main interest in improving the properties of insulating polymers has been on the use of nanoparticles, leading to nanodielectrics, it is pointed out here that larger microscopic hierarchical metal-oxide particles with high surface porosity also impart good insulation properties. The impact of the type of particle and its inherent properties (purity and conductivity) on the nanocomposite dielectric and insulating properties are also discussed based on data obtained by a newly developed technique to directly observe the charge distribution on a nanometer scale in the nanocomposite.

  • 327.
    Pourrahimi, Amir Massoud
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Göteborg, 41296, Sweden.
    Andersson, Richard L.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Tjus, Kåre
    Ström, Valter
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap.
    Björk, A.
    Olsson, Richard T.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Making an ultralow platinum content bimetallic catalyst on carbon fibres for electro-oxidation of ammonia in wastewater2019Ingår i: Sustainable Energy and Fuels, ISSN 2398-4902, Vol. 3, nr 8, s. 2111-2124Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Electrocatalysis of wastewater containing ammonia is a promising alternative to chemical and biological water purification for several reasons, one being that energy-rich hydrogen gas is generated as a by-product while the reaction can be strictly controlled to meet demands. An objective has been to reduce the loading of expensive platinum (Pt) in the catalyst electrodes, and to reduce the poisoning of the metal surface during the electrolysis. Herein, the co-deposition of a copper-platinum (Cu-Pt) bimetallic alloy onto carbon filaments, stripped from their polymeric coating, is shown to give an electrocatalytic performance superior to that of pure Pt at a content of less than 3 wt% Pt. The key to the enhanced performance was to take advantage of micrometer-sized carbon filaments to distribute a very large bimetallic alloy surface uniformly over the filaments. The Cu-Pt-alloy-coated filaments also suffer less electrode poisoning than pure Pt, and are bonded more strongly to the carbon fibre due to better mechanical interlocking between the bimetallic alloy and the carbon filaments. High-resolution electron microscopy studies combined with a tuned electro-deposition process made it possible to tailor the catalyst micro/nano morphology to reach a uniform coverage, surrounding the entire carbon filaments. The results are promising steps towards large-scale wastewater treatment, combined with clean energy production from regenerated hydrogen.

  • 328.
    Puziy, Alexander M.
    et al.
    NAS Ukraine, Inst Sorpt & Problems Endoecol, Naumov St 13, UA-03164 Kiev, Ukraine..
    Poddubnaya, Olga I.
    NAS Ukraine, Inst Sorpt & Problems Endoecol, Naumov St 13, UA-03164 Kiev, Ukraine..
    Sevastyanova, Olena
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Carbon Materials from Technical Lignins: Recent Advances2018Ingår i: Topics in Current Chemistry, ISSN 2365-0869, Vol. 376, nr 4, artikel-id 33Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Lignin, a major component of lignocellulosic biomass, is generated in enormous amounts during the pulp production. It is also a major coproduct of second generation biofuels. The effective utilization of lignin is critical for the accelerated development of the advanced cellulosic biorefinery. Low cost and availability of lignin make it attractive precursor for preparation of a range of carbon materials, including activated carbons, activated carbon fibers (CF), structural CF, graphitic carbons or carbon black that could be used for environmental protection, as catalysts, in energy storage applications or as reinforcing components in advanced composite materials. Technical lignins are very diverse in terms of their molecular weight, structure, chemical reactivity, and chemical composition, which is a consequence of the different origin of the lignin and the various methods of lignin isolation. The inherent heterogeneity of lignin is the main obstacle to the preparation of high-performance CF. Although lignin-based CF still do not compete with polyacrylonitrile-derived CF in mechanical properties, they nevertheless provide new markets through high availability and low production costs. Alternatively, technical lignin could be used for production of carbon adsorbents, which have very high surface areas and pore volumes comparable to the best commercial activated carbons. These porous carbons are useful for purifying gas and aqueous media from organic pollutants or adsorption of heavy metal ions from aqueous solutions. They also could be used as catalysts or electrodes in electrochemical applications.

  • 329.
    Qin, Shuang
    et al.
    3123 TAMU, Dept Mat Sci & Engn, College Stn, TX 77843 USA..
    Ghanadpour, Maryam
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Lazar, Simone
    3123 TAMU, Dept Chem, College Stn, TX 77843 USA..
    Köklükaya, Oruç
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Gerringer, Joseph
    3123 TAMU, Dept Mat Sci & Engn, College Stn, TX 77843 USA..
    Song, Yixuan
    3123 TAMU, Dept Mat Sci & Engn, College Stn, TX 77843 USA..
    Wågberg, Lars
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Grunlan, Jaime C.
    3123 TAMU, Dept Mat Sci & Engn, College Stn, TX 77843 USA.;3123 TAMU, Dept Chem, College Stn, TX 77843 USA..
    Super Gas Barrier and Fire Resistance of Nanoplatelet/Nanofibril Multilayer Thin Films2019Ingår i: Advanced Materials Interfaces, ISSN 2196-7350, Vol. 6, nr 2, artikel-id 1801424Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Cellulose nanofibrils (CNF) are abundant in the fiber cell walls of many plants and are considered a nearly inexhaustible resource. With the goal of improving the flame resistance and gas barrier properties of cellulose-based films, cationic CNF are assembled with anionic vermiculite (VMT) clay using the layer-by-layer deposition process. The highly aligned VMT nanoplatelets, together with cellulose nanofibrils, form a nanobrick wall structure that exhibits high optical transparency, flame resistance, super oxygen barrier, and high modulus. A 20 CNF/VMT bilayer (BL) nanocoating, with a thickness of only 136 nm, exhibits an oxygen transmission rate of 0.013 cc (m(2) day atm)(-1). With only 2 BL of CNF/VMT, the melting of flexible polyurethane foam exposed to a butane torch is prevented. These nanocoatings also exhibit a high elastic modulus (20 GPa) and hardness (1 GPa). This study demonstrates a unique, renewable, cellulose-based nanocoating that could be used in a variety of packaging and protection applications.

  • 330.
    Qin, Shuang
    et al.
    Texas A&M Univ, College Stn, TX USA..
    Pour, Maryam
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Lazar, Simone
    Texas A&M Univ, College Stn, TX USA..
    Song, Yixuan
    Texas A&M Univ, College Stn, TX USA..
    Gerringer, Joseph
    Texas A&M Univ, College Stn, TX USA..
    Wågberg, Lars
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Grunlan, Jaime
    Texas A&M Univ, College Stn, TX USA..
    Super gas barrier and flame retardant behavior of clay/cellulose nanofibril multilayer thin films2018Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 256Artikel i tidskrift (Övrigt vetenskapligt)
  • 331. Qu, M.
    et al.
    Nilsson, Fritjof
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Schubert, D. W.
    Effect of filler orientation on the electrical conductivity of carbon Fiber/PMMA composites2018Ingår i: Fibers, ISSN 2079-6439, Vol. 6, nr 1, artikel-id 3Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The electrical conductivity of extruded carbon fiber (CF)/Polymethylmethacrylate (PMMA) composites with controlled CF aspect ratio and filler fractions ranging from 0 to 50 vol. % has been investigated and analyzed. The composites were extruded through a capillary rheometer, utilizing either 1-mm or 3-mm diameter extrusion dies, resulting in cylindrical composite filaments of two different diameters. Since the average CF orientation becomes more aligned with the extrusion flow when the diameter of the extrusion dies decreases, the relationship between conductivity and average fiber orientation could therefore be examined. The room temperature conductivities of the extruded filaments as a function of CF fractions were fitted to theMcLachlan general effective medium (GEM) equation and the percolation thresholds were determined to 20.0 ± 2.5 vol. % and 32.0 ± 5.9 vol. % for the 3-mm (with CFs oriented less) and 1-mm(with CFs orientedmore) filaments, respectively. It turned out that the oriented CFs in the composite shift the percolation threshold to a higher value, however, the conductivity above the percolation threshold is higher for composites with oriented CFs. A novel approach based on the Balberg excluded volume theory was proposed to explain this counterintuitive phenomenon. 

  • 332.
    Qu, Muchao
    et al.
    Friedrich Alexander Univ Erlangen Nuremberg, Inst Polymer Mat, Martensstr 7, D-91058 Erlangen, Germany.;BPI, Key Lab Adv Fiber Technol, Dr Mack Str 77, D-90762 Furth, Germany..
    Nilsson, Fritjof
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Schubert, Dirk W.
    Friedrich Alexander Univ Erlangen Nuremberg, Inst Polymer Mat, Martensstr 7, D-91058 Erlangen, Germany.;BPI, Key Lab Adv Fiber Technol, Dr Mack Str 77, D-90762 Furth, Germany..
    Novel definition of the synergistic effect between carbon nanotubes and carbon black for electrical conductivity2019Ingår i: Nanotechnology, ISSN 0957-4484, E-ISSN 1361-6528, Vol. 30, nr 24, artikel-id 245703Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Anisotropic ternary composites comprising poly(methy-methacrylate) (PMMA), carbon black (CB), and carbon nanotubes (CNTs) were extruded using a capillary rheometer and the electrical conductivities of the composites were measured and presented in a detailed contour plot covering a large range of filler fractions (up to 30 vol% CNTs, 20 vol% CB). A recent generic conductivity model for ternary composites was successfully validated using the conductivity measurements. When analyzing the conductivity measurements using four traditional definitions of 'synergy' between two conductive fillers, no clear synergetic effect was observed between CB and CNT. Also, when all the conductivity data for ternary CNT/CB composites from the existing literature was carefully gathered and analyzed, the number of confirmed occurrences of strong and convincing CNT/CB synergies was surprisingly low. Finally, a novel definition of synergy based on the physical aspect, in particular, its maximum, the 'synergasm', was defined in order to obtain a more precise instrument for revealing regions of potential synergy.

  • 333.
    Quero, Franck
    et al.
    Univ Chile, Fac Ciencias Fis & Matemat, Dept Ingn Quim Biotecnol & Mat, Lab Nanocelulosa & Biomat, Beauchef 851, Santiago, Chile..
    Opazo, Genesis
    Univ Chile, Fac Ciencias Fis & Matemat, Dept Ingn Quim Biotecnol & Mat, Lab Nanocelulosa & Biomat, Beauchef 851, Santiago, Chile..
    Zhao, Yadong
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Feschotte-Parazon, Aymeric
    Univ Chile, Fac Ciencias Fis & Matemat, Dept Ingn Quim Biotecnol & Mat, Lab Nanocelulosa & Biomat, Beauchef 851, Santiago, Chile..
    Fernandez, Jeimy
    Univ Chile, Fac Ciencias Fis & Matemat, Dept Ingn Quim Biotecnol & Mat, Lab Nanocelulosa & Biomat, Beauchef 851, Santiago, Chile..
    Quintro, Abraham
    Univ Chile, Fac Ciencias Fis & Matemat, Dept Ingn Quim Biotecnol & Mat, Lab Nanocelulosa & Biomat, Beauchef 851, Santiago, Chile..
    Flores, Marcos
    Univ Chile, Fac Ciencias Fis & Matemat, Dept Fis, Lab Superficies & Nanomat, Beauchef 850, Santiago, Chile..
    Top-down Approach to Produce Protein Functionalized and Highly Thermally Stable Cellulose Fibrils2018Ingår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 19, nr 8, s. 3549-3559Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Protein-functionalized cellulose fibrils, having various amounts of covalently bonded proteins at their surface, were successfully extracted from the tunic of Pyura chilensis tunicates using successive alkaline extractions. Pure cellulose fibrils were also obtained by further bleaching and were used as reference material. Extraction yields of protein-functionalized cellulose fibrils were within the range of 62-76% by weight based on the dry initial tunic powder. Fourier-transform infrared and Raman spectroscopy confirmed the preservation of residual protein at the surface of cellulose fibrils, which was then quantified by X-ray photoelectron spectroscopy. The protein-functionalized cellulose fibrils were found to have relatively high crystallinity and their cellulose I crystalline structure was preserved upon applying alkaline treatments. The extracted cellulosic materials were found to be constituted of fibrils having a ribbon-like morphology with widths ranging from 30 nm up to similar to 400 nm. These protein-functionalized cellulose fibrils were found to have outstanding thermal stability with one of them having onset and peak degradation temperatures of similar to 350 and 374 degrees C, respectively. These values were found to be 24 and 41 degrees C higher than for bleached cellulose.

  • 334.
    Rahm, Martin
    et al.
    KTH, Skolan för kemivetenskap (CHE).
    Westlund, Robert
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Malmström, Eva
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    POLY 41-Dumbbell shaped tri-block copolymers of hyperbranched poly-3-ethyl-3-(hydroxymethyl)oxetane and polyethylene glycol through cationic ring opening polymerization2009Ingår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 238Artikel i tidskrift (Övrigt vetenskapligt)
  • 335. Ramani-Mohan, R. -K
    et al.
    Schwedhelm, I.
    Wistrand, Anna Finne
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Krug, M.
    Schwarz, T.
    Jakob, F.
    Walles, H.
    Hansmann, J.
    Deformation strain is the main physical driver for skeletal precursors to undergo osteogenesis in earlier stages of osteogenic cell maturation2018Ingår i: Journal of Tissue Engineering and Regenerative Medicine, ISSN 1932-6254, E-ISSN 1932-7005, Vol. 12, nr 3, s. e1474-e1479Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Mesenchymal stem cells play a major role during bone remodelling and are thus of high interest for tissue engineering and regenerative medicine applications. Mechanical stimuli, that is, deformation strain and interstitial fluid-flow-induced shear stress, promote osteogenic lineage commitment. However, the predominant physical stimulus that drives early osteogenic cell maturation is not clearly identified. The evaluation of each stimulus is challenging, as deformation and fluid-flow-induced shear stress interdepend. In this study, we developed a bioreactor that was used to culture mesenchymal stem cells harbouring a strain-responsive AP-1 luciferase reporter construct, on porous scaffolds. In addition to the reporter, mineralization and vitality of the cells was investigated by alizarin red staining and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide. Quantification of the expression of genes associated to bone regeneration and bone remodelling was used to confirm alizarin red measurements. Controlled perfusion and deformation of the 3-dimensional scaffold facilitated the alteration of the expression of osteogenic markers, luciferase activity, and calcification. To isolate the specific impact of scaffold deformation, a computational model was developed to derive a perfusion flow profile that results in dynamic shear stress conditions present in periodically loaded scaffolds. In comparison to actually deformed scaffolds, a lower expression of all measured readout parameters indicated that deformation strain is the predominant stimulus for skeletal precursors to undergo osteogenesis in earlier stages of osteogenic cell maturation. 

  • 336.
    Rashad, Ahmad
    et al.
    Univ Bergen, Dept Clin Dent, Bergen, Norway..
    Mohamed-Ahmed, Samih
    Univ Bergen, Dept Clin Dent, Bergen, Norway..
    Ojansivu, Miina
    Univ Bergen, Dept Clin Dent, Bergen, Norway.;Univ Tampere, Fac Med & Life Sci, Adult Stem Cell Res Grp, Tampere, Finland.;Univ Tampere, BioMediTech Inst, Tampere, Finland..
    Berstad, Kaia
    Univ Bergen, Dept Clin Dent, Bergen, Norway..
    Yassin, Mohammed A.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. Univ Bergen, Dept Clin Dent, Bergen, Norway..
    Kivijärvi, Tove
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Heggset, Ellinor Baevre
    RISE PFI, Trondheim, Norway..
    Syverud, Kristin
    RISE PFI, Trondheim, Norway.;Norwegian Univ Sci & Technol NTNU, Dept Chem Engn, Trondheim, Norway..
    Mustafa, Kamal
    Univ Bergen, Dept Clin Dent, Bergen, Norway..
    Coating 3D Printed Polycaprolactone Scaffolds with Nanocellulose Promotes Growth and Differentiation of Mesenchymal Stem Cells2018Ingår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 19, nr 11, s. 4307-4319Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    3D printed polycaprolactone (PCL) has potential as a scaffold for bone tissue engineering, but the hydrophobic surface may hinder optimal cell responses. The surface properties can be improved by coating the scaffold with cellulose nanofibrils material (CNF), a multiscale hydrophilic biocompatible biomaterial derived from wood. In this study, human bone marrow-derived mesenchymal stem cells were cultured on tissue culture plates (TCP) and 3D printed PCL scaffolds coated with CNF. Cellular responses to the surfaces (viability, attachment, proliferation, and osteogenic differentiation) were documented. CNF significantly enhanced the hydrophilic properties of PCL scaffolds and promoted protein adsorption. Live/dead staining and lactate dehydrogenase release assays confirmed that CNF did not inhibit cellular viability. The CNF between the 3D printed PCL strands and pores acted as a hydrophilic barrier, enhancing cell seeding efficiency, and proliferation. CNF supported the formation of a well-organized actin cytoskeleton and cellular production of vinculin protein on the surfaces of TCP and PCL scaffolds. Moreover, CNF-coated surfaces enhanced not only alkaline phosphatase activity, but also collagen Type-I and mineral formation. It is concluded that CNF coating enhances cell attachment, proliferation, and osteogenic differentiation and has the potential to improve the performance of 3D printed PCL scaffolds for bone tissue engineering.

  • 337.
    Rasheed, Faiza
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymera material. Swedish Univ Agr Sci, Dept Plant Breeding, Växtskyddsvägen 1, SE-23053 Alnarp, Sweden.
    Plivelic, Tomas S.
    Lund Univ, MAX IV Lab, Box 118, SE-22100 Lund, Sweden..
    Kuktaite, Ramune
    Swedish Univ Agr Sci, Dept Plant Breeding, Vaxtskyddsvagen 1, SE-23053 Alnarp, Sweden..
    Hedenqvist, Mikael S.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymera material.
    Johansson, Eva
    Swedish Univ Agr Sci, Dept Plant Breeding, Vaxtskyddsvagen 1, SE-23053 Alnarp, Sweden..
    Unraveling the Structural Puzzle of the Giant Glutenin Polymer-An Interplay between Protein Polymerization, Nanomorphology, and Functional Properties in Bioplastic Films2018Ingår i: ACS OMEGA, ISSN 2470-1343, Vol. 3, nr 5, s. 5584-5592Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A combination of genotype, cultivation environment, and protein separation procedure was used to modify the nanoscale morphology, polymerization, and chemical structure of glutenin proteins from wheat. A low-polymerized glutenin starting material was the key to protein-protein interactions mainly via SS cross-links during film formation, resulting in extended beta-sheet structures and propensity toward the formation of nanoscale morphologies at molecular level. The properties of glutenin bioplastic films were enhanced by the selection of a genotype with a high number of cysteine residues in its chemical structure and cultivation environment with a short grain maturation period, both contributing positively to gluten strength. Thus, a combination of factors affected the structure of glutenins in bioplastic films by forming crystalline beta-sheets and propensity toward the ordered nanostructures, thereby resulting in functional properties with high strength, stiffness, and extensibility.

  • 338. Rehman, Hafeez Ur
    et al.
    Chen, Yujie
    Hedenqvist, Mikael S.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Li, Hua
    Xue, Wenchao
    Guo, Yunlong
    Guo, Yiping
    Duan, Huanan
    Liu, Hezhou
    Self-Healing Shape Memory PUPCL Copolymer with High Cycle Life2018Ingår i: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 28, nr 7, artikel-id 1704109Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    New polyurethane-based polycaprolactone copolymer networks, with shape recovery properties, are presented here. Once deformed at ambient temperature, they show 100% shape fixation until heated above the melting point, where they recover the initial shape within 22 s. In contrast to current shape memory materials, the new materials do not require deformation at elevated temperature. The stable polymer structure of polyurethane yields a copolymer network that has strength of 10 MPa with an elongation at break of 35%. The copolymer networks are self-healing at a slightly elevated temperature (70 degrees C) without any external force, which is required for existing self-healing materials. This allows for the new materials to have a long life of repeated healing cycles. The presented copolymers show features that are promising for applications as temperature sensors and activating elements.

  • 339.
    Requena, Raquel
    et al.
    Univ Politecn Valencia, Inst Food Engn Dev, E-46022 Valencia, Spain.
    Jimenez-Quero, Amparo
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Glykovetenskap.
    Vargas, Maria
    Moriana Torro, Rosana
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymera material. SLU Swedish Univ Agr Sci, Dept Mol Sci, S-75007 Uppsala, Sweden.
    Chiralt, Amparo
    Vilaplana, Francisco
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemi, Glykovetenskap. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Integral Fractionation of Rice Husks into Bioactive Arabinoxylans, llulose Nanocrystals, and Silica Particles2019Ingår i: ACS Sustainable Chemistry and Engineering, ISSN 2168-0485, Vol. 7, nr 6, s. 6275-6286Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Rice husk is an important agricultural by-product that has not been exploited yet to full capacity for advanced applications. The feasibility of obtaining high-value products such as bioactive hemicelluloses and cellulose nanocrystals (CNCs) from rice husk is here demonstrated in a cascade biorefinery process using subcritical water extraction (SWE) prior to bleaching and acid hydrolysis and compared to traditional alkali pretreatments. The proposed SWE process enables the isolation of bioactive arabinoxylans with phenolic acid moieties, thus preserving their antioxidant and anti- bacterial properties that are lost during alkaline conditions. Bioactive Additionally, SWE can be combined with subsequent arabinoxylan Silica particles bleaching and acid hydrolysis to obtain CNCs with large aspect ratio, high crystallinity, and thermal stability. The hydrothermal process also enables the recovery of silica particles that are lost during the alkali step but can be recovered after the isolation of the CNCs. Our biorefinery strategy results in the integral valorization of rice husk into their molecular components (bioactive arabinoxylans, cellulose nanocrystals, and silica particles), which can be used as additives for food applications and as reinforcing agents in biocomposite materials, respectively.

  • 340. Reverdy, C.
    et al.
    Belgacem, N.
    Moghaddam, M. S.
    Sundin, M.
    Swerin, Agne
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik. RISE Research Institutes of Sweden – Bioscience and Materials, Box 5607, Stockholm, Sweden.
    Bras, J.
    One-step superhydrophobic coating using hydrophobized cellulose nanofibrils2018Ingår i: Colloids and Surfaces A: Physicochemical and Engineering Aspects, ISSN 0927-7757, E-ISSN 1873-4359, Vol. 544, s. 152-158Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Superhydrophobic surfaces have high potential in self-cleaning and anti-fouling applications. We developed a one-step superhydrophobic coating formulation containing sodium oleate (NaOl), hydrophobized precipitated calcium carbonate and biobased cellulose nanofibrils (CNFs) hydrophobized with either alkyl ketene dimer (AKD) or amino propyl trimethoxy silane (APMS) as a binder to fix and distribute the particles. Coatings were made on paperboard and the wetting behavior of the surface was assessed. Static, advancing and receding contact angles with water as well as roll-off and water shedding angle were compared to coatings made with styrene butadiene latex as binder instead of CNFs. Modifications with alkyl ketene dimer showed most promising results for a viable process in achieving superhydrophobic paperboard but required reformulation of the coating with optimized and reduced amount of NaOl to avoid surfactant-induced wetting via excess NaOl. A static water contact angle of 150° was reached for the CNF-AKD. The use of CNFs enables the improvement of coating quality avoiding cracking with the use of nanocellulose as a renewable binder.

  • 341.
    Rosén, Tomas
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Centra, Linné Flow Center, FLOW. KTH, Skolan för teknikvetenskap (SCI), Mekanik. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center. SUNY Stony Brook.
    Brouzet, Christophe
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center. KTH, Skolan för teknikvetenskap (SCI), Centra, Linné Flow Center, FLOW. KTH, Skolan för teknikvetenskap (SCI), Mekanik.
    Roth, Stephan V.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. DESY.
    Lundell, Fredrik
    KTH, Skolan för teknikvetenskap (SCI), Centra, Linné Flow Center, FLOW. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center. KTH, Skolan för teknikvetenskap (SCI), Mekanik.
    Söderberg, Daniel
    KTH, Skolan för teknikvetenskap (SCI), Mekanik. KTH, Skolan för teknikvetenskap (SCI), Centra, Linné Flow Center, FLOW. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Three-Dimensional Orientation of Nanofibrils in Axially Symmetric Systems Using Small-Angle X-ray Scattering2018Ingår i: The Journal of Physical Chemistry C, ISSN 1932-7447, E-ISSN 1932-7455, Vol. 122, nr 12, s. 6889-6899Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The increased availability and brilliance of new X-ray facilities have in the recent years opened up the possibility to characterize the alignment of dispersed anisotropic nanoparticles in various microfluidic applications, from hydrodynamic self-assemblies to flows in complex geometries. In such applications, it is vital to study the alignment of the nanoparticles in the flow, as this in turn affects the final properties of the self-assembled superstructures or those of the flow itself. Small-angle X-ray scattering (SAXS) is a well-suited characterization technique for this but typically provides the alignment in a projected plane perpendicular to the beam direction. In this work, we demonstrate a simple method to reconstruct the full three-dimensional orientation distribution function from a SAXS experiment through the assumption that the azimuthal angle of the nanoparticles around the flow direction is distributed uniformly, an assumption that is valid for a large range of nanoparticle flow processes. For demonstration purposes, the experimental results from previous works on hydrodynamic self-assembly of cellulose nanofibrils (CNFs) into filaments have been revised, resulting in a small correction to the presented order parameters. The results are then directly compared with simple numerical models to describe the increased alignment of CNFs both in the flowing system and during the drying of the filament. The proposed reconstruction method will allow for further improvements of theoretical or numerical simulations and consequently open up new possibilities for optimizing assembly processes, which include flow alignment of elongated nanoparticles.

  • 342.
    Rovera, Cesare
    et al.
    Univ Milan, Dept Food Environm & Nutr Sci, DeFENS, Via Celoria 2, I-20133 Milan, Italy..
    Ghaani, Masoud
    Univ Milan, Dept Food Environm & Nutr Sci, DeFENS, Via Celoria 2, I-20133 Milan, Italy..
    Santo, Nadia
    Univ Milan, Dept Biosci, Via Celoria 26, I-20133 Milan, Italy..
    Trabattoni, Silvia
    Univ Milano Bicocca, Dept Mat Sci, Via R Cozzi 55, I-20125 Milan, Italy..
    Olsson, Richard
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymera material.
    Romano, Diego
    Univ Milan, Dept Food Environm & Nutr Sci, DeFENS, Via Celoria 2, I-20133 Milan, Italy.;Univ Milan, Local Unit, Natl Consortium Mat Sci & Technol, INSTM, Via Celoria 2, I-20133 Milan, Italy..
    Farris, Stefano
    Univ Milan, Dept Food Environm & Nutr Sci, DeFENS, Via Celoria 2, I-20133 Milan, Italy.;Univ Milan, Local Unit, Natl Consortium Mat Sci & Technol, INSTM, Via Celoria 2, I-20133 Milan, Italy..
    Enzymatic Hydrolysis in the Green Production of Bacterial Cellulose Nanocrystals2018Ingår i: ACS SUSTAINABLE CHEMISTRY & ENGINEERING, ISSN 2168-0485, Vol. 6, nr 6, s. 7725-7734Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study, we extensively describe experimental models, with correlating experimental conditions, which were used to investigate the enzymatic hydrolysis of bacterial cellulose (BC) to obtain nanocrystals. Cellulase from Trichoderma reesei was used in five enzyme/BC ratios over a period of 74 h. The turbidity data was modeled using both logistic regression and empirical regression to determine the fractal kinetics, resulting in unique kinetic patterns for the mixtures that were richest in BC and in enzymes. The evolution of the yield was inversely related to the turbidity, as confirmed through a semiempirical approach that was adopted to model the experimental data. The yield values after 74 h of hydrolysis were higher for the substrate-rich mixtures (similar to 20%) than for the enzyme rich mixtures (similar to 5%), as corroborated by cellobiose and glucose quantification. Transmission electron microscopy and atomic force microscopy analyses revealed a shift from a fibril network to a needle-like morphology (i.e., aggregated nanocrystals or individual nanocrystals similar to 6 nm width and 200-800 nm in length) as the enzyme/BC ratios went from lower to higher. These results were explained in terms of the heterogeneous substrate model and the erosion model. This work initiated a promising, environmentally friendly method that could serve as an alternative to the commonly used chemical hydrolysis routes.

  • 343.
    Rozenbaum, Rene T.
    et al.
    Univ Groningen, Dept Biomed Engn, POB 196, NL-9700 AD Groningen, Netherlands.;Univ Med Ctr Groningen, POB 196, NL-9700 AD Groningen, Netherlands..
    Andrén, Oliver C. J.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    van der Mei, Henny C.
    Univ Groningen, Dept Biomed Engn, POB 196, NL-9700 AD Groningen, Netherlands.;Univ Med Ctr Groningen, POB 196, NL-9700 AD Groningen, Netherlands..
    Woudstra, Willem
    Univ Groningen, Dept Biomed Engn, POB 196, NL-9700 AD Groningen, Netherlands.;Univ Med Ctr Groningen, POB 196, NL-9700 AD Groningen, Netherlands..
    Busscher, Henk J.
    Univ Groningen, Dept Biomed Engn, POB 196, NL-9700 AD Groningen, Netherlands.;Univ Med Ctr Groningen, POB 196, NL-9700 AD Groningen, Netherlands..
    Malkoch, Michael
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Sharma, Prashant K.
    Univ Groningen, Dept Biomed Engn, POB 196, NL-9700 AD Groningen, Netherlands.;Univ Med Ctr Groningen, POB 196, NL-9700 AD Groningen, Netherlands..
    Penetration and Accumulation of Dendrons with Different Peripheral Composition in Pseudomonas aeruginosa Biofilms2019Ingår i: Nano letters (Print), ISSN 1530-6984, E-ISSN 1530-6992, Vol. 19, nr 7, s. 4327-4333Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Multidrug resistant bacterial infections threaten to become the number one cause of death by the year 2050. Development of antimicrobial dendritic polymers is considered promising as an alternative infection control strategy. For antimicrobial dendritic polymers to effectively kill bacteria residing in infectious biofilms, they have to penetrate and accumulate deep into biofilms. Biofilms are often recalcitrant to antimicrobial penetration and accumulation. Therefore, this work aims to determine the role of compact dendrons with different peripheral composition in their penetration into Pseudomonas aeruginosa biofilms. Red fluorescently labeled dendrons with pH-responsive NH3+ peripheral groups initially penetrated faster from a buffer suspension at pH 7.0 into the acidic environment of P. aeruginosa biofilms than dendrons with OH or COO- groups at their periphery. In addition, dendrons with NH3+ peripheral groups accumulated near the top of the biofilm due to electrostatic double-layer attraction with negatively charged biofilm components. However, accumulation of dendrons with OH and COO- peripheral groups was more evenly distributed across the depth of the biofilms than NH3+ composed dendrons and exceeded accumulation of NH3+ composed dendrons after 10 min of exposure. Unlike dendrons with NH3+ groups at their periphery, dendrons with OH or COO- peripheral groups, lacking strong electrostatic double-layer attraction with biofilm components, were largely washed-out during exposure to PBS without dendrons. Thus, penetration and accumulation of dendrons into biofilms is controlled by their peripheral composition through electrostatic double-layer interactions, which is an important finding for the further development of new antimicrobial or antimicrobial-carrying dendritic polymers.

  • 344.
    Sanchez, Carmen
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Wåhlander, Martin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Karlsson, Mattias E.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Quintero, Diana C. Marin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Hillborg, Henrik
    ABB Power Technol, SE-72178 Vasteras, Sweden..
    Malmström, Eva
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Nilsson, Fritjof
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Characterization of Reduced and Surface-Modified Graphene Oxide in Poly(Ethylene-co-Butyl Acrylate) Composites for Electrical Applications2019Ingår i: Polymers, ISSN 2073-4360, E-ISSN 2073-4360, Vol. 11, nr 4, artikel-id 740Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Promising electrical field grading materials (FGMs) for high-voltage direct-current (HVDC) applications have been designed by dispersing reduced graphene oxide (rGO) grafted with relatively short chains of poly (n-butyl methacrylate) (PBMA) in a poly(ethylene-co-butyl acrylate) (EBA) matrix. All rGO-PBMA composites with a filler fraction above 3 vol.% exhibited a distinct non-linear resistivity with increasing electric field; and it was confirmed that the resistivity could be tailored by changing the PBMA graft length or the rGO filler fraction. A combined image analysis- and Monte-Carlo simulation strategy revealed that the addition of PBMA grafts improved the enthalpic solubility of rGO in EBA; resulting in improved particle dispersion and more controlled flake-to-flake distances. The addition of rGO and rGO-PBMAs increased the modulus of the materials up to 200% and the strain did not vary significantly as compared to that of the reference matrix for the rGO-PBMA-2 vol.% composites; indicating that the interphase between the rGO and EBA was subsequently improved. The new composites have comparable electrical properties as today's commercial FGMs; but are lighter and less brittle due to a lower filler fraction of semi-conductive particles (3 vol.% instead of 30-40 vol.%).

  • 345. Scaffaro, R.
    et al.
    Maio, A.
    Lo Re, Giada
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Biokompositer.
    Parisi, A.
    Busacca, A.
    Advanced piezoresistive sensor achieved by amphiphilic nanointerfaces of graphene oxide and biodegradable polymer blends2018Ingår i: Composites Science And Technology, ISSN 0266-3538, E-ISSN 1879-1050, Vol. 156, s. 166-176Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This work focuses on the preparation of a piezoresistive sensor device, by exploiting an amphiphilic sample of graphene oxide (GO) as a compatibilizer for poly (lactic acid) (PLA)-Poly (ethylene-glycol) (PEG) blends. The presence of GO determined a high stiffening and strengthening effect, without affecting toughness, and allowed a good stability of mechanical properties up to 40 days. Moreover, GO endowed the materials with electrical properties highly sensitive to pressure and strain variations: the biodegradable pressure sensor showed a responsivity of 35 μA/MPa from 0.6 to 8.5 MPa, a responsivity around 19 μA/MPa from 8.5 to 25 MPa. For lower pressure values (around 0.16–0.45 MPa), instead, the responsivity increases up to 220 μA/MPa in terms of ΔI/ΔP (i.e. (ΔI/ΔI0)/P close to 1 kPa−1). Furthermore, this novel sensor is able to monitor submicrometric displacements with an impressive sensitivity (up to 25 μA/μm in terms of ΔI/ΔL, or 70 in terms of (ΔI/I0)/ε). We implemented a model able to predict pressure changes up to 25 MPa, by monitoring and measuring variations in electrical conductivity, thus paving the road to use these biodegradable, ecofriendly materials as low-cost sensors for a large pressure range.

  • 346.
    Schneider, Lynn M.
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik. KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Lättkonstruktioner.
    Ihrner, Niklas
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Ytbehandlingsteknik.
    Zenkert, Dan
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg, Lättkonstruktioner.
    Johansson, Mats
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Bicontinuous electrolytes via thermally initiated polymerization for structural lithium ion batteries.Manuskript (preprint) (Övrigt vetenskapligt)
  • 347.
    Schneider, Lynn M.
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Ihrner, Niklas
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Zenkert, Dan
    KTH, Skolan för teknikvetenskap (SCI), Farkost och flyg.
    Johansson, Mats
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Bicontinuous Electrolytes via Thermally Initiated Polymerization for Structural Lithium Ion Batteries2019Ingår i: ACS Applied Energy Materials, ISSN 2574-0962, Vol. 2, nr 6, s. 4362-4369Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Structural batteries (SBs) are a growing research subject worldwide. The idea is to provide massless energy by using a multifunctional material. This technology can provide a new pathway in electrification and offer different design opportunities and significant weight savings in vehicle applications. The type of SB discussed here is a multifunctional material that can carry mechanical loads and simultaneously provide an energy storage function. It is a composite material that utilizes carbon fibers (CFs) as electrodes and structural reinforcement which are embedded in a multifunctional polymer matrix (i.e., structural battery electrolyte). A feasible composite manufacturing method still needs to be developed to realize a full-cell SB. UV initiated polymerization induced phase separation (PIPS) has previously been used to make bicontinuous structural battery electrolytes (SBE) with good ionic conductivity and mechanical performance. However, UV-curing cannot be used for fabrication of a full cell SB since a full-cell is made of multiple layers of nontransparent CFs. The present paper investigates thermally initiated PIPS to prepare a bicontinuous SBE and an SB half-cell. In addition, the effect of curing temperature was examined with respect to curing performance, morphology, ionic conductivity, and mechanical and electrochemical performance. The study revealed that thermally initiated PIPS provides a robust and scalable process route to fabricate SBs. The results of this study are an important milestone in the development of SB technology as they allow for the SB fabrication for an actual application. However, other challenges still remain to be solved before this technology can be introduced into an application.

  • 348.
    Schuurmans, C. C. L.
    et al.
    Netherlands.
    Abbadessa, Anna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Bengtson, M. A.
    Netherlands.
    Pletikapic, G.
    Netherlands.
    Eral, H. B.
    Netherlands.
    Koenderink, G.
    Netherlands.
    Masereeuw, R.
    Netherlands.
    Hennink, W. E.
    Netherlands.
    Vermonden, T.
    Netherlands.
    Complex coacervation-based loading and tunable release of a cationic protein from monodisperse glycosaminoglycan microgels2018Ingår i: Soft Matter, ISSN 1744-683X, E-ISSN 1744-6848, Vol. 14, nr 30, s. 6327-6341Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Glycosaminoglycans (GAGs) are of interest for biomedical applications because of their ability to retain proteins (e.g. growth factors) involved in cell-to-cell signaling processes. In this study, the potential of GAG-based microgels for protein delivery and their protein release kinetics upon encapsulation in hydrogel scaffolds were investigated. Monodisperse hyaluronic acid methacrylate (HAMA) and chondroitin sulfate methacrylate (CSMA) micro-hydrogel spheres (diameters 500-700 μm), were used to study the absorption of a cationic model protein (lysozyme), microgel (de)swelling, intra-gel lysozyme distribution and its diffusion coefficient in the microgels dispersed in buffers (pH 7.4) of varying ionic strengths. Upon incubation in 20 mM buffer, lysozyme was absorbed up to 3 and 4 mg mg−1 dry microspheres for HAMA and CSMA microgels respectively, with loading efficiencies up to 100%. Binding stoichiometries of disaccharide : lysozyme (10.2 : 1 and 7.5 : 1 for HAMA and CSMA, respectively) were similar to those for GAG-lysozyme complex coacervates based on soluble GAGs found in literature. Complex coacervates inside GAG microgels were also formed in buffers of higher ionic strengths as opposed to GAG-lysozyme systems based on soluble GAGs, likely due to increased local anionic charge density in the GAG networks. Binding of cationic lysozyme to the negatively charged microgel networks resulted in deswelling up to a factor 2 in diameter. Lysozyme release from the microgels was dependent on the ionic strength of the buffer and on the number of anionic groups per disaccharide, (1 for HAMA versus 2 for CSMA). Lysozyme diffusion coefficients of 0.027 in HAMA and <0.006 μm2 s−1 in CSMA microgels were found in 170 mM buffer (duration of release 14 and 28 days respectively). Fluorescence Recovery After Photobleaching (FRAP) measurements yielded similar trends, although lysozyme diffusion was likely altered due to the negative charges introduced to the protein through the FITC-labeling resulting in weaker protein-matrix interactions. Finally, lysozyme-loaded CSMA microgels were embedded into a thermosensitive hydrogel scaffold. These composite systems showed complete lysozyme release in ∼58 days as opposed to only 3 days for GAG-free scaffolds. In conclusion, covalently crosslinked methacrylated GAG hydrogels have potential as controlled release depots for cationic proteins in tissue engineering applications.

  • 349. Senf, Deborah
    et al.
    Ruprecht, Colin
    Farahani, Saina Kishani
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Matic, Aleksandar
    Toriz, Guillermo
    Gatenholm, Paul
    Wågberg, Lars
    KTH, Tidigare Institutioner (före 2005), Fiber- och polymerteknologi.
    Pfrengle, Fabian
    Tailormade Polysaccharides with Defined Branching Patterns:Enzymatic Polymerization of Arabinoxylan Oligosaccharides2018Ingår i: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, s. 12163-12168Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
    Abstract [en]

    The heterogeneous nature of non-cellulosic polysaccharides,such as arabinoxylan, makes it difficult tocorrelate molecular structure with macroscopic properties. Tostudy the impact of specific structural features of the polysaccharideson crystallinity or affinity to other cell wall components,collections of polysaccharides with defined repeatingunits are required. Herein, a chemoenzymatic approach toartificial arabinoxylan polysaccharides with systematicallyaltered branching patterns is described. The polysaccharideswere obtained by glycosynthase-catalyzed polymerization ofglycosyl fluorides derived from arabinoxylan oligosaccharides.X-ray diffraction and adsorption experiments on cellulosicsurfaces revealed that the physicochemical properties of thesynthetic polysaccharides strongly depend on the specificnature of their substitution patterns. The artificial polysaccharidesallow structure–property relationship studies that are notaccessible by other means.

  • 350.
    Senf, Deborah
    et al.
    Max Planck Inst Colloids & Interfaces, Dept Biomol Syst, Muhlenberg 1, D-14476 Potsdam, Germany.;Free Univ Berlin, Inst Chem & Biochem, Arnimallee 22, D-14195 Berlin, Germany..
    Ruprecht, Colin
    Max Planck Inst Colloids & Interfaces, Dept Biomol Syst, Muhlenberg 1, D-14476 Potsdam, Germany..
    Kishani, Saina
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Matic, Aleksandar
    Max Planck Inst Colloids & Interfaces, Dept Biomol Syst, Muhlenberg 1, D-14476 Potsdam, Germany.;Univ Potsdam, Dept Chem, Karl Liebknecht Str 24-25, D-14476 Potsdam, Germany..
    Toriz, Guillermo
    Chalmers Univ Technol, Dept Chem & Chem Engn, Wallenberg Wood Sci Ctr & Biopolymer Technol, S-41296 Gothenburg, Sweden..
    Gatenholm, Paul
    Chalmers Univ Technol, Dept Chem & Chem Engn, Wallenberg Wood Sci Ctr & Biopolymer Technol, S-41296 Gothenburg, Sweden..
    Wågberg, Lars
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi. KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center.
    Pfrengle, Fabian
    Max Planck Inst Colloids & Interfaces, Dept Biomol Syst, Muhlenberg 1, D-14476 Potsdam, Germany.;Free Univ Berlin, Inst Chem & Biochem, Arnimallee 22, D-14195 Berlin, Germany..
    Tailormade Polysaccharides with Defined Branching Patterns: Enzymatic Polymerization of Arabinoxylan Oligosaccharides2018Ingår i: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 57, nr 37, s. 11987-11992Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The heterogeneous nature of non-cellulosic polysaccharides, such as arabinoxylan, makes it difficult to correlate molecular structure with macroscopic properties. To study the impact of specific structural features of the polysaccharides on crystallinity or affinity to other cell wall components, collections of polysaccharides with defined repeating units are required. Herein, a chemoenzymatic approach to artificial arabinoxylan polysaccharides with systematically altered branching patterns is described. The polysaccharides were obtained by glycosynthase-catalyzed polymerization of glycosyl fluorides derived from arabinoxylan oligosaccharides. X-ray diffraction and adsorption experiments on cellulosic surfaces revealed that the physicochemical properties of the synthetic polysaccharides strongly depend on the specific nature of their substitution patterns. The artificial polysaccharides allow structure-property relationship studies that are not accessible by other means.

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