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  • 1.
    Ahlinder, Astrid
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    Fuoco, Tiziana
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi, Polymerteknologi.
    Finne Wistrand, Anna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Medical grade polylactide, copolyesters and polydioxanone: Rheological properties and melt stability2018Inngår i: Polymer testing, ISSN 0142-9418, E-ISSN 1873-2348, Vol. 72, s. 214-222Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Rheological measurements have shown that lactide-based copolymers with L-lactide content between 50 and 100 mol% with varying comonomers, as well as polydioxanone (PDX), can be used in additive manufacturing analogously to poly(L-lactide) (PLLA) if their melt behaviour are balanced. The results indicate that copolymers can be melt processed if the temperature is adjusted according to the melting point, and parameters such as the speed are tuned to conteract the elastic response. Small amplitude oscillatory shear (SAOS) rheology, thermal and chemical characterisation allowed us to map the combined effect of temperature and frequency on the behaviour of six degradable polymers and their melt stability. Values of complex viscosity and Tan delta obtained through nine time sweeps by varying temperature and frequency showed that the molecular structure and the number of methylene units influenced the results, copolymers of L-lactide with D-Lactide (PDLLA) or glycolide (PLGA) had an increased elastic response, while copolymers with trimethylene carbonate (PLATMC) or epsilon-caprolactone (PCLA) had a more viscous behaviour than PLLA, with respect to their relative melting points. PDLLA and PLGA require an increased temperature or lower speed when processed, while PLATMC and PCLA can be used at a lower temperature and/or higher speed than PLLA. PDX showed an increased viscosity compared to PLLA but a similar melt behaviour. Negligible chain degradation were observed, apart from PLGA.

  • 2.
    Albertsson, Ann-Christine
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Finne-Wistrand, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Edlund, Ulrica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Degradable polymers with tailored properties for biomedical materials2009Inngår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 238Artikkel i tidsskrift (Annet vitenskapelig)
  • 3.
    Albertsson, Ann-Christine
    et al.
    KTH, Skolan för kemivetenskap (CHE).
    Odelius, Karin
    KTH, Skolan för kemivetenskap (CHE).
    Finne Wistrand, Anna
    KTH, Skolan för kemivetenskap (CHE). Royal Inst Technol, Sch Chem Sci & Engn, SE-10044 Stockholm, Sweden..
    POLY 554-Controlled synthesis of star-shaped homo- and co-polymers of aliphatic polyesters2006Inngår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 232Artikkel i tidsskrift (Annet vitenskapelig)
  • 4.
    Albertsson, Ann-Christine
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Odelius, Karin
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Finne-Wistrand, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Controlled synthesis of star-shaped homo- and co-polymers of aliphatic polyesters2006Inngår i: 7th International Biorelated Polymers Symposium, 2006, s. 37-38Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The challenges in finding a material with the proper characteristics for a given tissue engineering application are several. One solution is improving the ability to tailor the mechanical and physical properties along with the degradation profile of aliphatic polyesters, by for example alterations in their composition and architecture. In this study, well-defined star-shaped aliphatic polyesters constituted of four arms were synthesized. As a model system, L,L-lactide and a spirocyclic tin initiator was chosen and the affect of the solvent, temperature and monomer-to-initiator ratio on the number average molecular weight, the molecular weight distribution and the conversion of the polymers was shown. Consecutively, we proved that well-defined star-shaped block copolymers composed of 1,5-dioxepan-2-one and L,L-lactide with narrow molecular weight distributions and controlled block lengths can be synthesized using this system.

  • 5.
    Albertsson, Ann-Christine
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Varma, Indra Kumari
    Centre for Polymer Science and Engineering, Indian Institute of Technology, Dehli, India.
    Lochab, Bimlesh
    Centre for Polymer Science and Engineering, Indian Institute of Technology, Dehli, India.
    Finne Wistrand, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Kumar, Kamlesh
    Centre for Polymer Science and Engineering, Indian Institute of Technology, Dehli, India.
    Design and Syntesis of Different Types of Poly(Lactic acid)2010Inngår i: Poly(Lactic Acid): Synthesis, Structures, Properties, Processing and Applications / [ed] Rafael Auras, Loong-Tak Lim, Susan E. M. Selke, Hideto Tsuji, John Wiley & Sons, 2010, s. 43-58Kapittel i bok, del av antologi (Annet vitenskapelig)
  • 6.
    Andronova, Natalia
    et al.
    KTH, Tidigare Institutioner                               , Fiber- och polymerteknologi.
    Finne, Anna
    KTH, Tidigare Institutioner                               , Fiber- och polymerteknologi.
    Albertsson, Ann-Christine
    KTH, Tidigare Institutioner                               , Fiber- och polymerteknologi.
    Fibrillar structure of resorbable microblock copolymers based on 1,5-dioxepan-2-one and epsilon-caprolactone2003Inngår i: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 41, nr 15, s. 2412-2423Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The copolymerization of 1,5-dioxepan-2-one (DXO) and E-caprolactone, initiated by a five-membered cyclic tin alkoxide initiator, was performed in chloroform at 60 degreesC. Copolymers with different molar ratios of DXO (25, 40, and 60%) were synthesized and characterized. C-13 NMR spectroscopy of the carbonyl region revealed the formation of copolymers with a blocklike structure. Differential scanning calorimetry measurements showed that all the copolymers had a single glass transition between -57 and -49 degreesC and a melting temperature in the range of 30.1-47.7 degreesC, both of which were correlated with the amount of DXO. An increase in the amount of DXO led to an increase in the glass-transition temperature and to a decrease in the melting temperature. Dynamic mechanical thermal analysis measurements confirmed the results of the calorimetric analysis, showing a single sharp drop in the storage modulus in the temperature region corresponding to the glass transition. Tensile testing demonstrated good mechanical properties with a tensile strength of 27-39 MPa and an elongation at break of up to 1400%. The morphology of the copolymers was examined with polarized optical microscopy and atomic force microscopy; the films that crystallized from the melt showed a short fibrillar structure (with a length of 0.05-0.4 mum) in contrast to the untreated solution-cast films. (C) 2003 Wiley Periodicals, Inc.

  • 7. Arvidson, K.
    et al.
    Abdallah, B. M.
    Applegate, L. A.
    Baldini, N.
    Cenni, E.
    Gomez-Barrena, E.
    Granchi, D.
    Kassem, M.
    Konttinen, Y. T.
    Mustafa, K.
    Pioletti, D. P.
    Sillat, T.
    Finne-Wistrand, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Bone regeneration and stem cells2011Inngår i: Journal of Cellular and Molecular Medicine (Print), ISSN 1582-1838, E-ISSN 1582-4934, Vol. 15, nr 4, s. 718-746Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    Introduction Bone fracture healing and healing problems Biomaterial scaffolds and tissue engineering in bone formation Bone tissue engineering Biomaterial scaffolds Synthetic scaffolds Micro- and nanostructural properties of scaffolds Conclusion Mesenchymal stem cells and osteogenesis Bone tissue Origin of osteoblasts Isolation and characterization of bone marrow derived MSC In vitro differentiation of MSC into osteoblast lineage cells In vivo differentiation of MSC into bone Factors and pathways controlling osteoblast differentiation of hMSC Defining the relationship between osteoblast and adipocyte differentiation from MSC MSC and sex hormones Effect of aging on osteoblastogenesis Conclusion Embryonic, foetal and adult stem cells in osteogenesis Cell-based therapies for bone Specific features of bone cells needed to be advantageous for clinical use Development of therapeutic biological agents Clinical application concerns Conclusion Platelet-rich plasma (PRP), growth factors and osteogenesis PRP effects in vitro on the cells involved in bone repair PRP effects on osteoblasts PRP effects on osteoclasts PRP effects on endothelial cells PRP effects in vivo on experimental animals The clinical use of PRP for bone repair Non-union Distraction osteogenesis Spinal fusion Foot and ankle surgery Total knee arthroplasty Odontostomatology and maxillofacial surgery Conclusion Molecular control of osteogenesis TGF-beta signalling FGF signalling IGF signalling PDGF signalling MAPK signalling pathway Wnt signalling pathway Hedgehog signalling Notch signalling Ephrin signalling Transcription factors regulating osteoblast differentiation Conclusion Summary This invited review covers research areas of central importance for orthopaedic and maxillofacial bone tissue repair, including normal fracture healing and healing problems, biomaterial scaffolds for tissue engineering, mesenchymal and foetal stem cells, effects of sex steroids on mesenchymal stem cells, use of platelet-rich plasma for tissue repair, osteogenesis and its molecular markers. A variety of cells in addition to stem cells, as well as advances in materials science to meet specific requirements for bone and soft tissue regeneration by addition of bioactive molecules, are discussed.

  • 8. Bartaula-Brevik, Sushma
    et al.
    Pedersen, Torbjorn O.
    Blois, Anna L.
    Papadakou, Panagiota
    Finne-Wistrand, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Xue, Ying
    Bolstad, Anne Isine
    Mustafa, Kamal
    Leukocyte transmigration into tissue-engineered constructs is influenced by endothelial cells through Toll-like receptor signaling2014Inngår i: Stem Cell Research & Therapy, E-ISSN 1757-6512, Vol. 5, s. 143-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Introduction: Inflammation plays a crucial role in tissue regeneration, wound healing, and the success of tissue-engineered constructs. The aim of this study was to investigate the influence of human umbilical vein endothelial cells (ECs) on leukocyte transmigration when co-cultured with primary human bone marrow-derived multipotent stromal cells (MSCs). Methods: MSCs with and without ECs were cultured in poly (L-lactide-co-1, 5-dioxepan-2-one) (poly (LLA-co-DXO)) scaffolds for 1 week in vitro in a bioreactor system, after which they were implanted subcutaneously in non-obese diabetic/severe combined immunodeficient mice. After 1 and 3 weeks, scaffolds were retrieved, and the mRNA expression of interleukin 1-beta (IL-1 beta), IL-6, IL-10, hypoxia-inducible factor 1-alpha (HIF-1 alpha), HIF-1 beta, and mammalian target of rapamycin was examined by real-time reverse transcription-polymerase chain reaction. Furthermore, immunofluorescent staining was performed for IL-1 beta, IL-6, neutrophils, and CD11b. In addition, Western blotting was done for IL-1 beta and IL-6. Leukocyte transmigration genes and genes in Toll-like receptor pathways, expressed by MSCs cultured in vitro with or without ECs, were further investigated with a microarray dataset. Results: In vitro, genes involved in leukocyte transmigration and Toll-like receptor pathways were clearly influenced by the addition of ECs. Platelet/endothelial cell adhesion molecule-1 (PECAM-1) and cadherin-5 (CDH5), both genes involved in leukocyte transmigration, were expressed significantly higher in the MSC/EC group. In vivo, the MSC/EC group showed higher mRNA expression of hypoxia-inducible factors HIF-1 alpha and HIF-1 beta. The mRNA expression of anti-inflammatory cytokine IL-10 showed no significant difference, whereas the mRNA and protein expression of pro-inflammatory cytokines IL-1 beta and IL-6 were lower in the MSC/EC group. The quantitative analysis of immunofluorescent staining revealed a significant difference in the number of neutrophils migrating into constructs, with the highest density found in the MSC/EC group. The number of macrophages positive for IL-6 and CD11b was significantly reduced in the MSC/EC group. Conclusions: The recruitment of leukocytes into tissue-engineered constructs with MSCs is strongly influenced by the addition of ECs via activation of leukocyte transmigration and Toll-like receptor pathways.

  • 9. Bartaula-Brevik, Sushma
    et al.
    Pedersen, Torbjorn O.
    Finne-Wistrand, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Bolstad, Anne Isine
    Mustafa, Kamal
    Angiogenic and Immunomodulatory Properties of Endothelial and Mesenchymal Stem Cells2016Inngår i: Tissue Engineering. Part A, ISSN 1937-3341, E-ISSN 1937-335X, Vol. 22, nr 3-4, s. 244-252Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    It has been suggested that the effect of implanted cells on the local environment is important when selecting the appropriate cell type for tissue regeneration. Our aim was to compare the local tissue response to implanted human mesenchymal stem cells (MSC) and human umbilical vein endothelial cells (EC). MSC and EC were cultured in poly(l-lactide-co-1,5-dioxepan-2-one) scaffolds for 1 week in a bioreactor system, after which they were implanted subcutaneously in NOD/SCID mice. After 3 weeks, scaffolds were retrieved, and the mRNA expression of selected genes involved in hypoxia and inflammation was examined by real-time reverse transcription polymerase chain reaction and correlated with immunofluorescent staining for corresponding proteins. The Toll-like receptor signaling pathway was examined by superarray hybridization. The expression of 53 angiogenesis-related proteins was investigated by a proteome profiler angiogenesis antibody array kit. Vascularization was quantified using immunohistochemistry for CD31. The expression of hypoxia-inducible factors and biomarkers for angiogenesis was more strongly upregulated in response to implanted EC than to MSC, suggesting a higher sensitivity to low oxygen tension among EC. Hypoxic signaling was increased after implantation of EC compared with MSC, leading to a prolonged acute inflammatory phase that promoted ingrowth of vascular cells and establishment of the circulation. Inflammatory cytokines were also differently expressed at the gene and protein levels in the two experimental groups, resulting in altered recruitment of acute and chronic inflammatory cells. The end result of these differences was increased vessel formation within the constructs in the EC group.

  • 10. Danmark, Staffan
    et al.
    Finne Wistrand, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Wendel, Mikael
    Arvidson, Kristina
    Albertsson, Ann-Christine
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Mustafa, Kamal
    Osteogenic Differentiation by Rat Bone Marrow Stromal Cells on Customized Biodegradable Polymer Scaffolds2010Inngår i: Journal of bioactive and compatible polymers (Print), ISSN 0883-9115, E-ISSN 1530-8030, Vol. 25, nr 2, s. 207-223Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this report, poly(L-lactide-co-epsilon-caprolactone), poly(LLA-co-CL) and poly(L-lactide-co-1,5-dioxepan-2-one), poly(LLA-co-DXO) were evaluated and compared for potential use in bone tissue engineering constructs together with bone marrow stromal cells (BMSC). The copolymers were tailored to reduce the level of harmful tin residuals in the scaffolding. BMSC isolated from Sprague-Dawley rats were seeded onto the scaffolds and cultured in vitro for up to 21 days. Cell spreading and proliferation was analyzed after 72 h by scanning electron microscopy and thiazolyl blue tetrazolium bromide (MTT) conversion assay. Osteogenic differentiation of BMSC was evaluated by real-time PCR after 14 and 21 days of culture. Hydrophilicity was significantly different between poly(LLA-co-CL) and poly(LLA-co-DXO) with the latter being more hydrophilic. After 72 h, both scaffolds supported increased cell proliferation and the mRNA expression of osteocalcin and osteopontin was significantly increased after 21 days. Further investigation of these constructs, with lower levels of tin residuals, are being pursued.

  • 11.
    Dånmark, Staffan
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Finne-Wistrand, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Albertsson, Ann-Christine
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Patarroyo, Manuel
    Institutionen for Odontologi, Karolinska Institute.
    Mustafa, Kamal
    Insititutt for klinisk Odontologi, Medicinska och Odontologiska Fakulteten, Universitetet i Bergen, Norge.
    Integrin-mediated adhesion of human mesenchymal stem cells to extracellular matrix proteins adsorbed to polymer surfaces2012Inngår i: Biomedical Materials, ISSN 1748-6041, E-ISSN 1748-605X, Vol. 7, nr 3, s. 035011-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In vitro, degradable aliphatic polyesters are widely used as cell carriers for bone tissue engineering, despite their lack of biological cues. Their biological active surface is rather determined by an adsorbed layer of proteins from the surrounding media. Initial cell fate, including adhesion and proliferation, which are key properties for efficient cell carriers, is determined by the adsorbed layer of proteins. Herein we have investigated the ability of human bone marrow derived stem cells (hBMSC) to adhere to extracellular matrix (ECM) proteins, including fibronectin and vitronectin which are present in plasma and serum. hBMSC expressed integrins for collagens, laminins, fibronectin and vitronectin. Accordingly, hBMSC strongly adhered to these purified ECM proteins by using the corresponding integrins. Although purified fibronectin and vitronectin adsorbed to aliphatic polyesters to a lower extent than to cell culture polystyrene, these low levels were sufficient to mediate adhesion of hBMSC. It was found that plasma- and serum-coated polystyrene adsorbed significant levels of both fibronectin and vitronectin, and fibronectin was identified as the major adhesive component of plasma for hBMSC; however, aliphatic polyesters adsorbed minimal levels of fibronectin under similar conditions resulting in impaired cell adhesion. Altogether, the results suggest that the efficiency of aliphatic polyesters cell carriers could be improved by increasing their ability to adsorb fibronectin.

  • 12.
    Dånmark, Staffan
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Finne-Wistrand, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Edlund, Ulrica
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Albertsson, Ann-Christine
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Mustafa, Kamal
    Insititutt for klinisk Odontologi, Medicinska och Odontologiska Fakulteten, Universitetet i Bergen, Norge.
    Enhanced Osteoconductivity of Degradable co-Polyester Scaffolds through Covalent Immobilization of BMP-2Manuskript (preprint) (Annet vitenskapelig)
  • 13.
    Dånmark, Staffan
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Finne-Wistrand, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Schander, K.
    Hakkarainen, Minna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Arvidson, K.
    Mustafa, K.
    Albertsson, Ann-Christine
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    In vitro and in vivo degradation profile of aliphatic polyesters subjected to electron beam sterilization2011Inngår i: ACTA BIOMATERIALIA, ISSN 1742-7061, Vol. 7, nr 5, s. 2035-2046Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Degradation characteristics in response to electron beam sterilization of designed and biodegradable aliphatic polyester scaffolds are relevant for clinically successful synthetic graft tissue regeneration Scaffold degradation in vitro and in vivo were documented and correlated to the macroscopic structure and chemical design of the original polymer The materials tested were of inherently diverse hydrophobicity and crystallinity poly(L-lactide) (poly(LLA)) and random copolymers from L-lactide and epsilon-caprolactone or 1.5-dioxepan-2-one, fabricated into porous and non-porous scaffolds After sterilization, the samples underwent hydrolysis in vitro for up to a year In vivo, scaffolds were surgically implanted into rat calvarial defects and retrieved for analysis after 28 and 91 days In vitro, poly(L-lactide-co-1, 5-dioxepan-2-one) (poly(LLA-co-DXO)) samples degraded most rapidly during hydrolysis, due to the pronounced chain-shortening reaction caused by the sterilization. This was indicated by the rapid decrease in both mass and molecular weight of poly(LLA-co-DXO). Poly(L-lactide-co-epsilon-caprolactone) (poly(LLA-co-CL)) samples were also strongly affected by sterilization, but mass loss was more gradual; molecular weight decreased rapidly during hydrolysis Least affected by sterilization were the poly(LLA) samples, which subsequently showed low mass loss rate and molecular weight decrease during hydrolysis. Mechanical stability varied greatly. poly(LLA-co-CL) withstood mechanical testing for up to 182 days, while poly(LLA) and poly(LLA-co-DXO) samples quickly became too brittle Poly(LLA-co-DXO) samples unexpectedly degraded more rapidly in vitro than in vivo. After sterilization by electron beam irradiation, the three biodegradable polymers present widely diverse degradation profiles, both in vitro and in vivo. Each exhibits the potential to be tailored to meet diverse clinical tissue engineering requirements

  • 14.
    Dånmark, Staffan
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Gladnikoff, Micha
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Frisk, Thomas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik.
    Zelenina, Marina
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik.
    Mustafa, Kamal
    Russom, Aman
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Finne-Wistrand, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Development of a novel microfluidic device for long-term in situ monitoring of live cells in 3-dimensional matrices2012Inngår i: Biomedical microdevices (Print), ISSN 1387-2176, E-ISSN 1572-8781, Vol. 14, nr 5, s. 885-893Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Using the latest innovations in microfabrication technology, 3-dimensional microfluidic cell culture systems have been developed as an attractive alternative to traditional 2-dimensional culturing systems as a model for long-term microscale cell-based research. Most microfluidic systems are based on the embedding of cells in hydrogels. However, physiologically realistic conditions based on hydrogels are difficult to obtain and the systems are often too complicated. We have developed a microfluidic cell culture device that incorporates a biodegradable rigid 3D polymer scaffold using standard soft lithography methods. The device permits repeated high-resolution fluorescent imaging of live cell populations within the matrix over a 4 week period. It was also possible to track cell development at the same spatial location throughout this time. In addition, human primary periodontal ligament cells were induced to produce quantifiable calcium deposits within the system. This simple and versatile device should be readily applicable for cell-based studies that require long-term culture and high-resolution bioimaging.

  • 15.
    Dånmark, Staffan
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Gladnikoff, Micha
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Frisk, Thomas
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik.
    Zelenina, Marina
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik.
    Mustafa, Kamal
    Insititutt for klinisk Odontologi, Medicinska och Odontologiska Fakulteten, Universitetet i Bergen, Norge.
    Russom, Aman
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik, Cellens fysik.
    Finne-Wistrand, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Development of Novel Microfluidic Device for Long-Term in situ Monitoring of Live Cells in 3-dimensional MatricesManuskript (preprint) (Annet vitenskapelig)
  • 16.
    Fagerland, Jenny
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Finne-Wistrand, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Mapping the synthesis and the impact of low molecular weight PLGA-g-PEG on sol-gel properties to design hierarchical porous scaffolds2013Inngår i: Journal of polymer research, ISSN 1022-9760, E-ISSN 1572-8935, Vol. 21, nr 1, s. 337-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Bone morphogenetic protein 2 (BMP-2)-functionalized poly(l-lactide-co-epsilon-caprolactone) (PLCL) porous scaffolds have shown promising results in bone tissue regeneration studies. It is believed that even better results are achieved by hierarchical porous scaffolds and a designed sequential release of growth factors. We therefore synthesized (l-lactide-co-glycolide)-g-poly(ethylene glycol) (PLGA-g-PEG) oligomers which could be injected into PLCL porous scaffolds. They were synthesized by ring-opening polymerization and carefully characterized by nuclear magnetic resonance spectroscopy (NMR), matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS), and size exclusion chromatography (SEC). The sol-gel transition temperature, pH, and functional life were determined and correlated with the molecular structure of PLGA-g-PEG. We found that low molecular weight PLGA-g-PEG was obtained and poly(l-lactide-co-glycolide-co-poly(ethylene glycol) methyl ether) (PLGA-MPEG) appeared to contribute to gelation. It was possible to design a system that formed a hydrogel within 1 min at 37 A degrees C with a pH between 6 and 7 and with a functional life of around 1 month. These low molecular weight thermosensitive PLGA-g-PEG oligomers, which can be injected into PLCL scaffolds, appear promising for bone tissue engineering applications.

  • 17.
    Fagerland, Jenny
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Finne-Wistrand, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Numata, Keiji
    Short One-Pot Chemo-Enzymatic Synthesis of L-Lysine and L-Alanine Diblock Co-Oligopeptides2014Inngår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 15, nr 3, s. 735-743Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Amphiphilic diblock co-oligopeptides are interesting and functional macromolecular materials for biomedical applications because of their self-assembling properties. Here, we developed a synthesis method for diblock co-oligopeptides by using chemo-enzymatic polymerization, which was a relatively short (30 min) and efficient reaction (over 40% yield). Block and random oligo(L-lysine-co-L-alanine) [oligo(Lys-co-Ala)] were synthesized using activated papain as enzymatic catalyst. The reaction time was optimized according to kinetic studies of oligo(L-alanine) and oligo(L-lysine). Using H-1 NMR spectroscopy and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, we confirmed that diblock and random co-oligopeptides were synthesized. Optical microscopy further revealed differences in the crystalline morphology between random and block co-oligopeptides. Plate-like, hexagonal, and hollow crystals were formed due to the strong impact of the monomer distribution and pH of the solution. The different crystalline structures open up interesting possibilities to form materials for both tissue engineering and controlled drug/gene delivery systems.

  • 18.
    Fagerland, Jenny
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Finne-Wistrand, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Numata, Keiji
    Short one-pot chemo-enzymatic synthesis of L-lysine and L-alanine diblock copolypeptidesManuskript (preprint) (Annet vitenskapelig)
  • 19.
    Fagerland, Jenny
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Finne-Wistrand, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Pappalardo, Daniela
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. University of Sannio, Italy.
    Modulating the thermal properties of poly(hydroxybutyrate) by the copolymerization of rac-beta-butyrolactone with lactide2016Inngår i: New Journal of Chemistry, ISSN 1144-0546, E-ISSN 1369-9261, Vol. 40, nr 9, s. 7671-7679Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Biobased poly(hydroxybutyrate) is produced by microorganisms under controlled conditions. It is a linear, high molecular weight, fully isotactic and highly crystalline polymer. However, it has poor mechanical and thermal properties. We have modulated the thermal properties of this material by ring-opening co-polymerization of rac-beta-butyrolactone (BL) with lactide (LA) in the presence of salan-based yttrium and aluminum catalysts. The prepared poly(hydroxybutyrate-co-lactide) copolymers were characterized by proton and carbon nuclear magnetic resonance (H-1 and C-13 NMR), size exclusion chromatography (SEC) and differential scanning calorimetry (DSC) analyses. The salan-yttrium compound was a more effective catalyst compared to the aluminum compound, affording high molecular weight copolymers with higher monomer conversion and a monomodal distribution of the molecular weights. The kinetic experiments showed a higher rate of polymerization for the LA with respect to the BL. The copolymers were amorphous and DSC showed unique transition temperatures for all of the samples. The formation of a gradient copolymer is proposed.

  • 20.
    Finne, Anna
    KTH, Tidigare Institutioner                               , Polymerteknologi.
    Novel Possibilities for Advanced Molecular Structure Design for Polymers and Networks2003Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Synthetic and degradable polymers are an attractive choicein many areas, since it is possible to control the way in whichthey are manufactured; more specifically, pathways tomanipulate the architecture, the mechanical properties and thedegradation times have been identified. In this work,L-lactide, 1,5-dioxepan-2-one and ε-caprolactone were usedas monomers to synthesize polymers with different architecturesby ring-opening polymerization. By using novel initiators,triblock copolymers, functionalized linear macromonomers andstar-shaped aliphatic polyesters with well-defined structureshave been synthesized. To synthesize triblock copolymers,cyclic germanium initiators were studied. The polymerizationproceeded in a controlled manner although the reaction rateswere low. To introduce functionality into the polymer backbone,functionalized cyclic tin alkoxides were prepared and used asinitiators. During the insertion-coordination polymerization,the initiator fragment consisting mainly of a double bond wasincorporated into the polymer backbone. The double bond wasalso successfully epoxidized and this gave unique possibilitiesof synthesizing graft polymers with precise spacing. Themacromonomer technique is a very effective method for producingwell-defined graft polymers. Spirocyclic tin initiators weresynthesized and used to construct star-shaped polymers. Thestar-shaped polymers were subsequently crosslinked in apolycondensation reaction. These crosslinked structures swelledin water, and swelling tests showed that by changing thestructure of the hydrogel network, the degree of swelling canbe altered. A first evaluation of the surface characteristicsof the linear triblock copolymers was also performed. AFManalysis of the heat-treated surfaces revealed nanometer-scalefibers and tests showed that keratinocytes were able to growand proliferate on these surfaces.

  • 21.
    Finne, Anna
    et al.
    KTH, Tidigare Institutioner                               , Polymerteknologi.
    Albertsson, Ann-Christine
    KTH, Tidigare Institutioner                               , Polymerteknologi.
    Controlled synthesis of star-shaped L-lactide polymers using new spirocyclic tin initiators2002Inngår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 3, nr 4, s. 684-690Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The reaction between pentaerythritol ethoxylate compounds and dibutyltin oxide was developed as a route to synthesize two new spirocyclic tin initiators. The initiators were successfully synthesized and they were characterized by H-1 NMR and differential scanning calorimetry (DSC). The H-1 NMR spectra showed the characteristic signals for the methylene protons in the ether chains. Furthermore, the usefulness of the new initiators was examined in ring-opening polymerizations of L-lactide in chloroform at 60 degreesC. L-Lactide was polymerized at monomer-to-initiator ([M]/[I]) ratios between 20 and 500. The results indicated that the initiation was instantaneous and that the molecular weight distribution was very narrow, <1.13, The number average molecular weight could be controlled by the [M]/[I] ratio, and the yield was very high. H-1 NMR, size exclusion chromatography, and DSC were used to clarify the architecture, The expected results were obtained. The star-shaped polymers had a smaller hydrodynamic volume, and the melting point was lower than that obtained for the corresponding linear poly(L-lactide).

  • 22.
    Finne, Anna
    et al.
    KTH, Tidigare Institutioner                               , Polymerteknologi.
    Albertsson, Ann-Christine
    KTH, Tidigare Institutioner                               , Polymerteknologi.
    New functionalized polyesters to achieve controlled architectures2004Inngår i: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 42, nr 3, s. 444-452Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Following our continued interest in the production of bioerodible and biodegradable functional polymers for biomedical applications, we synthesized and characterized new unsaturated polyesters. The presence of functional groups in the polymer backbone provided sites for chemical modification, and through a variation in the structure, the physical properties, such as the hydrophilicity and solubility, could be affected. With 1,1-di-n-butyl-stanna-2,7-dioxacyclo-4-heptene as the initiator in the ring-opening polymerization of polyesters, a new set of functionalized polyesters was created. The polymerization of epsilon-caprolactone resulted in poly(epsilon-caprolactone) with a double bond incorporated into the structure. The polymers were obtained in a controlled manner with low molecular dispersities. The double bond was previously incorporated into L-lactide polymers, and the two reactions were compared in this study. The conversion of E-caprolactone, with a degree of polymerization of 50, was completed within 140 min, whereas for L-lactide, only a 45% conversion took place in the same period of time. The dispersities were somewhat higher with E-caprolactone because of the higher reaction rate and, therefore, lower selectivity. The incorporated C-C double bond in the polyesters provided a variety of opportunities for further modifications. In this case, the double bond of the L-lactide macromonomers was oxidized into epoxides. Epoxidation was carried out with m-chloroperoxybenzoic acid as a chemical reagent. The conversion of the double bonds into epoxides was completed, and the obtained yields were good (>95%). As a result of the mild reaction conditions, the epoxidation of the double bond was carried out quantitatively without any side reactions.

  • 23.
    Finne, Anna
    et al.
    KTH, Tidigare Institutioner                               , Polymerteknologi.
    Albertsson, Ann-Christine
    KTH, Tidigare Institutioner                               , Polymerteknologi.
    Polyester hydrogels with swelling properties controlled by the polymer architecture, molecular weight, and crosslinking agent2003Inngår i: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 41, nr 9, s. 1296-1305Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Hydrogels of poly(1,5-dioxepan-2-one) and hydrogels of block copolymers of poly(1,5-dioxepan-2-one) and poly(L-lactide) were synthesized. Both star-shaped polymers and linear polymers were polymerized with ring-opening polymerization and crosslinked in situ with a tetrafunctional acid chloride (1,2,3,4-cyclopentane tetracarboxylic acid chloride) or a difunctional acid chloride (succinyl chloride). Different network architectures were synthesized in this way. The initial monomer concentrations and the molecular weights of the macromonomers were also altered. The networks were characterized with H-1 NMR and differential scanning calorimetry, and the swelling abilities of the different hydrogels were investigated in water and dichloromethane. The ratio of the monomer to the crosslinking agent was assessed by the quantification of the signal intensities in the H-1 NMR spectra of the swelled network and agreed with the theoretical crosslinking density. Both the homopolymers of 1,5-dioxepan-2-one and the copolymers of 1,5-dioxepan-2-one and L-lactide swelled to a high degree in water. The swelling properties of the materials could be varied over a broad range by changes in the architecture, molecular weight, and content of the precursor in the network. Star-shaped poly(1,5-dioxepan-2-one) crosslinked with a difunctional acid chloride had the highest degree of swelling among the different homopolymer hydrogels. This network also had the lowest glass-transition temperature because of the flexible units in the structure. The same trends found for the homopolymer hydrogels were also seen in the hydrogels with block copolymers. The hydrogels swelled enormously in dichloromethane, and as in water, the star-shaped copolymer crosslinked with a difunctional acid chloride had the highest degree of swelling.

  • 24.
    Finne, Anna
    et al.
    KTH, Tidigare Institutioner                               , Polymerteknologi.
    Andronova, Natalia
    KTH, Tidigare Institutioner                               , Polymerteknologi.
    Albertsson, Ann-Christine
    KTH, Tidigare Institutioner                               , Polymerteknologi.
    Well-organized phase-separated nanostructured surfaces of hydrophilic/hydrophobic ABA triblock copolymers2003Inngår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 4, nr 5, s. 1451-1456Artikkel i tidsskrift (Fagfellevurdert)
  • 25.
    Finne, Anna
    et al.
    KTH, Tidigare Institutioner                               , Polymerteknologi.
    Reema,
    Albertsson, Ann-Christine
    KTH, Tidigare Institutioner                               , Polymerteknologi.
    Use of germanium initiators in ring-opening polymerization of L-lactide2003Inngår i: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 41, nr 19, s. 3074-3082Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Three different, new germanium initiators were used for ring-opening polymerization Of L-lactide. Chlorobenzene and 120 degreesC was a usable polymerization system for solution polymerization, and the results from the polymerizations depended on the initiator structure and bulkiness around the insertion site. The average molecular weights as measured by size exclusion chromatography increased linearly with the monomer conversion, and the molecular weight dispersity was around 1.2 for initiators 1 and 2, whereas it was around 1.4 for initiator 3. The average molecular weight of poly(L-lactide) could be controlled with all three initiators by adding different ratios of monomer and initiator. The reaction rate for the solution polymerization was, however, overall extremely slow. With an initial monomer concentration of 1 M and a monomer-to-initiator ratio of 50, the conversion was 93% after 161 h for the fastest initiator. In bulk polymerization, 160 degreesC, the conversion was 90% after 10 h.

  • 26.
    Finne Wistrand, Anna
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Albertsson, Ann-Christine
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    The use of polymer design in resorbable colloids2006Inngår i: Annual review of materials research (Print), ISSN 1531-7331, E-ISSN 1545-4118, Vol. 36, s. 369-395Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    During the past decade, researchers in the field of polymer chemistry have developed a wide range of very powerful procedures for constructing ever-more-sophisticated polymers. These methods subsequently have been used in suitable systems to solve specific medical problems. This is complicated, and many key factors such as mechanical properties, biocompatibility, biodegradation, stability, and degradation profile must be considered. Colloid particle systems can be used to solve many biomedical- and pharmaceutical-related problems, and it is expected that nanotechnology can be used to develop these materials, devices, and systems even further. For example, an injectible scaffold system with a defined release and degradation profile has huge potential for the repair and regeneration of damaged tissues. This short, nonexhaustive review presents examples of polymer architecture in resorbable particles that have been compared and tested in biomedical applications. We also discuss the design of polymers for core-shell structures.

  • 27.
    Finne Wistrand, Anna
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Albertsson, Ann-Christine
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Tuned mechanical properties achieved by varying polymer structure: Knowledge that generates new materials for tissue engineering2007Inngår i: Chinese Journal of Polymer Science, ISSN 0256-7679, E-ISSN 1439-6203, Vol. 25, nr 2, s. 113-118Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    By changing both the monomer composition and the polymer structure, we have varied the mechanical properties of resorbable polymers. The polymers were synthesized by ring-opening polymerization using L-lactide (LLA), epsilon-caprolactone (epsilon CL), trimethylene carbonate (TMC) and 1,5-dioxepan-2-one (DXO) as monomers. Well-defined triblock copolymers, microblock copolymers and networks have been evaluated, and comparisons between them show that it is possible to tune the mechanical properties. Triblock copolymers with an amorphous middle block of poly(1,5-dioxepan-2-one) (PDXO) and semi-crystalline end-blocks of poly(epsilon-caprolactone) (PCL) were stronger and had a higher strain at break than triblock copolymers with poly(L-lactide) (PLLA) as end-blocks. Polymers with both DXO and TMC in the amorphous middle-block and PLLA as end-blocks showed a lower stress at break, but the material gained elasticity, a property which is very valuable in tissue engineering. Mechanical properties of networks, synthesized by a novel method, containing PDXO and PCL are also presented. Although it is difficult to compare them with the uncross-linked polymers, this is an additional way to modify and widen the properties.

  • 28.
    Finne Wistrand, Anna
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Albertsson, Ann-Christine
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Kwon, Oh Hyeong
    Kawazoe, Naoki
    Chen, Guoping
    Kang, Inn-Kyu
    Hasuda, Hirokazu
    Gong, Jiansheng
    Ito, Yoshihiro
    Resorbable Scaffolds from Three Different Techniques: Electrospun Fabrics, Salt-Leaching Porous Films, and Smooth Flat Surfaces2008Inngår i: Macromolecular Bioscience, ISSN 1616-5187, E-ISSN 1616-5195, Vol. 8, nr 10, s. 951-959Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Nanofibrous scaffolds of poly[(L-lactide)-co-(1,5-dioxepan-2-one)] generated by electrospinning have been compared with porous films obtained by solvent cast/salt leaching and homogeneous films. A comparison between the fibrous materials and the homogeneous solvent-cast films revelead that the surface of the nanofibers was more hydrophobic and that the nanofibers were degraded more rapidly in the presence of proteinase. It was obvious that the strain-to-break was reduced by the nanofiber formation, it decreased from 370% to 130% independent of fiber diameter. These values were however considerably higher than the strain-to-break of the solvent-cast/salt leaching scaffold. In addition, the nanofibrous material accelerated the adhesion and growth of the mesenchymal stem cell compared to the smooth material.

  • 29.
    Finne Wistrand, Anna
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Hakkarainen, Minna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Polylactide:  2011Inngår i: Handbook of Engineering and Speciality Thermoplastics: Polyethers and Polyesters / [ed] S. Thomas and V. P.M., Hoboken, NJ, USA: John Wiley & Sons, 2011, s. 349-376Kapittel i bok, del av antologi (Annet vitenskapelig)
    Abstract [en]

    The production of durable functional products without using petroleumbased raw materials is a focus of much academic research today but it is also prioritized by many industries. Many questions still remain concerning the use, production and properties of bio-based and/or degradable polymers and whether or not they are more environmentally friendly than oil-based products. Polylactide is a bio-based compostable thermoplastic that is considered as one of the most promising materials for replacement of traditional volume plastics. The properties of polylactide can be tuned to resemble polystyrene, poly(ethylene terephthalate) or polyolefins by controlling the stereochemistry by copolymerization or blending. This chapter reviews the life-cycle of polylactide based materials as well as the properties and applications. The recent trends in the area are also discussed.

  • 30.
    Finne Wistrand, Anna
    et al.
    KTH, Tidigare Institutioner                               , Fiber- och polymerteknologi.
    Ryner, M.
    Albertsson, Ann-Christine
    KTH, Tidigare Institutioner                               , Polymerteknologi.
    Degradable polymers: Design, synthesis and testing2003Inngår i: Macromolecular Symposia, ISSN 1022-1360, E-ISSN 1521-3900, Vol. 195, s. 241-246Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The object for our research is to mimic Nature's perfectly designed resorbable materials to obtain important materials, which are biocompatible and degradable. We have therefore synthesized different architectures and copolymers of aliphatic polyesters with ring-opening polymerization. The first studies of these materials properties show that properties like hydrophilicity and tensile properties can be controlled.

  • 31.
    Fuoco, Tiziana
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Finne Wistrand, Anna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Enhancing the Properties of Poly(epsilon-caprolactone) by Simple and Effective Random Copolymerization of epsilon-Caprolactone with p-Dioxanone2019Inngår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 20, nr 8, s. 3171-3180Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We have developed a straightforward strategy to obtain semicrystalline and random copolymers of epsilon-caprolactone (CL) and p-dioxanone (DX) with thermal stabilities similar to poly(epsilon-caprolactone), PCL, but with a faster- hydrolytic degradation rate-CL/DX-copolymers-are promising inks when printing scaffolds aimed for tissue engineering. Such copolymers behave similar to PCL and resorb faster. The copolymers were synthesized by bulk ring-opening copolymerization, achieving a high yield; a molecular weight, M-n, of 57-176 kg mol(-1); and an inherent viscosity of 1.7-1.9 dL g(-1). The copolymer microstructure consisted of long CL blocks that are separated by isolated DX units. The block length and the melting point were a linear function of the DX content. The copolymers crystallize as an orthorhombic lattice that is typical for PCL, and they formed more elastic, softer, and less hydrophobic films with faster degradation rates than PCL. Relatively high thermal degradation temperatures (above 250 C), similar to PCL, were estimated by thermogravimetric analysis, and copolymer filaments for three-dimensional printing and scaffolds were produced without thermal degradation.

  • 32.
    Fuoco, Tiziana
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. University of Salerno, Italy.
    Finne-Wistrand, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Pappalardo, Daniela
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. University of Sannio, Italy.
    A Route to Aliphatic Poly(ester)s with Thiol Pendant Groups: From Monomer Design to Editable Porous Scaffolds2016Inngår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 17, nr 4, s. 1383-1394Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Biodegradable aliphatic polyesters such as poly(lactide) and poly(ϵ-caprolactone), largely used in tissue engineering applications, lack suitable functional groups and biological cues to enable interactions with cells. Because of the ubiquity of thiol groups in the biological environment and the pliability of thiol chemistry, we aimed to design and synthesize poly(ester) chains bearing pendant thiol-protected groups. To achieve this, 3-methyl-6-(tritylthiomethyl)-1,4-dioxane-2,5-dione, a lactide-type monomer possessing a pendant thiol-protected group, was synthesized. This molecule, when used as a monomer in controlled ring-opening polymerization in combination with lactide and ϵ-caprolactone, appeared to be a convenient "building block" for the preparation of functionalized aliphatic copolyesters, which were easily modified further. A polymeric sample bearing pyridyl disulfide groups, able to bind a cysteine-containing peptide, was efficiently obtained from a two-step modification reaction. Porous scaffolds were then prepared by blending this latter copolymer sample with poly(l-lactide-co-ϵ-caprolactone) followed by salt leaching. A further disulfide exchange reaction performed in aqueous medium formed porous scaffolds with covalently linked arginine-glycine-aspartic acid sequences. The scaffolds were characterized by thermal and mechanical tests, and scanning electron microscopy surface images revealed a highly porous morphology. Moreover, a cytotoxicity test indicated good cell viability.

  • 33.
    Fuoco, Tiziana
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Mathisen, T.
    Finne Wistrand, Anna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Minimizing the time gap between service lifetime and complete resorption of degradable melt-spun multifilament fibers2019Inngår i: Polymer degradation and stability, ISSN 0141-3910, E-ISSN 1873-2321, Vol. 163, s. 43-51Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We have succeeded to modulated the degradation rate of poly(L-lactide) (PLLA) melt-spun multifilament fibers to extend the service lifetime and increase the resorption rate by using random copolymers of L-lactide and trimethylene carbonate (TMC). The presence of TMC units enabled an overall longer service lifetime but faster degradation kinetics than PLLA. By increasing the amount of TMC up to 18 mol%, multifilament fibers characterized by a homogenous degradation profile could be achieved. Such composition allowed, once the mechanical integrity was lost, a much longer retention of mechanical integrity and a faster rate of mass loss than samples containing less TMC. The degradation profile of multifilament fibers consisting of (co)polymers containing 0, 5, 10 and 18 mol% of TMC has been identified during 45 weeks in vitro hydrolysis following the molecular weight decrease, mass loss and changes in microstructure, crystallinity and mechanical properties. The fibers degraded by a two-step, autocatalyzed bulk hydrolysis mechanism. A high rate of molecular weight decrease and negligible mass loss, with a consequent drop of the mechanical properties, was observed in the early stage of degradation for fibers having TMC content up to 10 mol%. The later stage of degradation was, for these samples, characterized by a slight increase in the mass loss and a negligible molecular weight decrease. Fibers prepared with the 18 mol% TMC copolymer showed instead a more homogenous molecular weight decrease ensuring mechanical integrity for longer time and faster mass loss during the later stage of degradation.

  • 34.
    Fuoco, Tiziana
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Mathisen, Torbjorn
    Finne Wistrand, Anna
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Fiber- och polymerteknologi.
    Poly(L-lactide) and Poly(L-lactide-co-trimethylene carbonate) Melt-Spun Fibers: Structure-Processing-Properties Relationship2019Inngår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 20, nr 3, s. 1346-1361Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    l-Lactide/trimethylene carbonate copolymers have been produced as multifilament fibers by high-speed melt-spinning. The relationship existing between the composition, processing parameters and physical properties of the fibers has been disclosed by analyzing how the industrial process induced changes at the macromolecular level, i.e., the chain microstructure and crystallinity development. A poly(l-lactide) and three copolymers having trimethylene carbonate contents of 5, 10 and 18 mol % were synthesized with high molecular weight (M n ) up to 377 kDa and narrow dispersity. Their microstructure, crystallinity and thermal properties were dictated by the composition. The spinnability was then assessed for all the as-polymerized materials: four melt-spun multifilament fibers with increasing linear density were collected for each (co)polymer at a fixed take-up speed of 1800 m min -1 varying the mass throughput during the extrusion. A linear correlation resulted between the as-spun fiber properties and the linear density. The as-spun fibers could be further oriented, developing more crystallinity and improving their tensile properties by a second stage of hot-drawing. This ability was dependent on the composition and crystallinity achieved during the melt-spinning and the parameters selected for the hot-drawing, such as temperature, draw ratio and input speed. The crystalline structure evolved to a more stable form, and the degree of crystallinity increased from 0-52% to 25-66%. Values of tensile strength and Young's modulus up to 0.32-0.61 GPa and 4.9-8.4 GPa were respectively achieved.

  • 35.
    Fuoco, Tiziana
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Pappalardo, Daniela
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi. Department of Science and Technology, University of Sannio, via dei Mulini 59/A, 82100 Benevento, Italy.
    Wistrand, Anna Finne
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi.
    Redox-Responsive Disulfide Cross-Linked PLA-PEG Nanoparticles2017Inngår i: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 50, nr 18, s. 7052-7061Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We have developed a strategy for the preparation of redox-responsive PEG PLA-based nanoparticles containing disulfide bonds that can be disassembled in the presence of cellular concentrations of glutathione. Functionalized poly-(lactide)s were prepared by ring-opening copolymerization of L-lactide and 3-methyl-6-(tritylthiomethyl)-1,4-dioxane-2,5-dione, a monomer bearing a pendant trityl-thiol group, followed by the postpolymerization modification of trityl-thiol into pyridyl disulfide groups. Polymeric networks composed of PLA and PEG blocks linked by disulfide bonds were prepared by a disulfide exchange reaction between the functionalized PLAs and telechelic PEG having thiol groups at both ends, HS-PEG-SH, in DMF. When dialyzed against water, they assembled into dispersible nanoparticles, with a flowerlike structure having a hydrophobic core and a hydrophilic shell, with sizes in the range 167-300 nm that are suitable for drug delivery. The effects of the number of functional groups, molecular weight, and concentration on the nanoparticle size were evaluated. The stability of the nanoparticles after dilution and the redox-responsive behavior in the presence of different concentrations of glutathione were assessed. The hydrophobic molecule Nile red could be encapsulated in the nanoparticles and then released in the presence of glutathione at cellular concentration.

  • 36.
    Glavas, Lidija
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Guo, Baolin
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Finne Wistrand, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Odelius, Karin
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Albertsson, Ann-Christine
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Tuned electrical conductivity by macromolecular architecture: Electroactive and degradable block copolymers based on polyesters and aniline oligomers2012Inngår i: Abstract of Papers of the American Chemical Society, ISSN 0065-7727, Vol. 244Artikkel i tidsskrift (Annet vitenskapelig)
  • 37.
    Guo, Baolin
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Finne-Wistrand, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Albertsson, Ann-Christine
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Degradable and Electroactive Hydrogels with Tunable Electrical Conductivity and Swelling Behavior2011Inngår i: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 23, nr 5, s. 1254-1262Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Degradable electrically conducting hydrogels (DECHs), which combine the unique properties of degradable polymers and electrically conducting hydrogels, were synthesized by introducing biodegradable segments into conductive hydrogels. These DECHs were obtained by joining together the photopolymerized macromer acrylated poly(D,L-lactide)-poly(ethylene glycol)-poly(D,L-lactide) (AC-PLA-PEG-PLA-AC), glycidyl methacrylate (GMA), ethylene glycol dimethacrylate (EGDMA) network and aniline tetramer (AT) by the coupling reaction between AT and the GMA The electrical conductivity and swelling behavior of these DECHs were tuned by changing the AT content in the hydrogels, the cross-linking degree, and the environmental pH value. The good electroactivity and thermal stability of these hydrogels were demonstrated by UV-vis spectroscopy, cyclic voltammetry, and TGA tests. The chemical structure and morphology of these polymers were characterized by NMR, FT-IR, SEC, and SEM. These hydrogels possessing both degradability and electrical conductivity represent a new class of biomaterial and will lead to various new possibilities in biomedical applications.

  • 38.
    Guo, Baolin
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Finne-Wistrand, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Albertsson, Ann-Christine
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Electroactive Hydrophilic Polylactide Surface by Covalent Modification with Tetraaniline2012Inngår i: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 45, nr 2, s. 652-659Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Covalent surface functionalization is presented as a versatile tool to increase the hydrophilicity and to introduce the electroactivity of polyester films. Acrylic acid and maleic anhydride were photografted onto a polylactide (PLA) surface with a "grafting from" method to increase the surface wettability, and the subsequent coupling of conductive aniline oligomer was used to introduce electroactivity to the PLA surface. The photopolymerization of maleic anhydride and acrylic acid and the coupling, of aniline tetramer (AT) were characterized by FT-IR, UV, and TGA. The surface morphology of the PLA surface before and after modification was examined by scanning electron microscopy (SEM) and atomic force microscopy (AFM). A medium hydrophilic surface of PLA was achieved by surface modification with maleic anhydride, acrylic acid, and AT. An electrically conductive surface was obtained after grafting with AT, and the conductivity increased with increasing AT content on the surface. The hydrophilic and electroactive surface of polyesters while retaining their bulk properties offers new possibilities in biomedical applications, such as bone, cartilage, neural, and cardiovascular tissue engineering.

  • 39.
    Guo, Baolin
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Finne-Wistrand, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Albertsson, Ann-Christine
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Enhanced Electrical Conductivity by Macromolecular Architecture: Hyperbranched Electroactive and Degradable Block Copolymers Based on Poly(epsilon-caprolactone) and Aniline Pentamer2010Inngår i: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 43, nr 10, s. 4472-4480Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present macromolecular architecture design as a useful tool to enhance the conductivity of degradable polymers. Linear and hyperbranched copolymers with electrical conductivity and biodegradability were synthesized by an "A(2) + B-n (n=2, 3, 4)" strategy using carboxyl-capped aniline pen tamer (CCAP) and branched poly(epsilon-caprolactone)s (PCLs) by coupling reactions. A more hydrophilic surface and lower crystallinity of the doped emeraldine state of aniline pentamer (EM A P) copolymer was achieved compared with PCLs, and TGA results demonstrated that the CCAP contents in the copolymers were almost the same. The structure of the polymers was characterized by FT-IR. NMR, and SEC. Good electroactivity of the copolymers was confirmed by UV and cyclic voltammetry (CV), and CV showed three pairs of redox peaks. The hyperbranched copolymers had a higher conductivity than the linear ones. It is suggested that the higher conductivity of the hyperbranched copolymer is due to the ordered distribution of peripheral EMAP segments that more easily form a conductive network. Therefore, the conductivity of the polymers is improved and controlled by the macromolecular architecture.

  • 40.
    Guo, Baolin
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Finne-Wistrand, Anna
    Albertsson, Ann-Christine
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Facile Synthesis of Degradable and Electrically Conductive Polysaccharide Hydrogels2011Inngår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 12, nr 7, s. 2601-2609Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Degradable and electrically conductive polysaccharide hydrogels (DECPHs) have been synthesized by functionalizing polysaccharide with conductive aniline oligomers. DECPHs based on chitosan (CS), aniline tetramer (AT), and glutaraldehyde were obtained by a facile one-pot reaction by using the amine group of CS and AT under mild conditions, which avoids the multistep reactions and tedious purification involved in the synthesis of degradable conductive hydrogels in our previous work. Interestingly, these one-pot hydrogels possess good film-forming properties, electrical conductivity, and a pH-sensitive swelling behavior. The chemical structure and morphology before and after swelling of the hydrogels were verified by FT-IR, NMR, and SEM. The conductivity of the hydrogels was tuned by adjusting the content of AT. The swelling ratio of the hydrogels was altered by the content of tetraaniline and crosslinker. The hydrogels underwent slow degradation in a buffer solution. The hydrogels obtained by this facile approach provide new possibilities in biomedical applications, for example, biodegradable conductive hydrogels, films, and scaffolds for cardiovascular tissue engineering and controlled drug delivery.

  • 41.
    Guo, Baolin
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Finne-Wistrand, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Albertsson, Ann-Christine
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Molecular Achitecture of electroactive and biodegradable copolymers composed of polyactide and carboxyl-capped aniline trimer2010Inngår i: Biomacromolecules, ISSN 1525-7797, E-ISSN 1526-4602, Vol. 11, nr 4, s. 855-863Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    wo-, four-, and six-armed branched copolymers with electroactive and biodegradable properties were synthesized by coupling reactions between poly(l-lactides) (PLLAs) with different architecture and carboxyl-capped aniline trimer (CCAT). The aniline oligomer CCAT was prepared from amino-capped aniline trimer and succinic anhydride. FT-IR, NMR, and SEC analyses confirmed the structure of the branched copolymers. UV−vis spectra and cyclic voltammetry of CCAT and copolymer solution showed good electroactive properties, similar to those of polyaniline. The water contact angle of the PLLAs was the highest, followed by the undoped copolymer and the doped copolymers. The values of doped four-armed copolymers were 54−63°. Thermal properties of the polymers were studied by DSC and TGA. The copolymers had better thermal stability than the pure PLLAs, and the Tg between 48−58 °C and Tm between 146−177 °C of the copolymers were lower than those of the pure PLLA counterparts. This kind of electroactive and biodegradable copolymer has a great potential for applications in cardiovascular or neuronal tissue engineering.

  • 42.
    Guo, Baolin
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Finne-Wistrand, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Albertsson, Ann-Christine
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Simple Route to Size-Tunable Degradable and Electroactive Nanoparticles from the Self-Assembly of Conducting Coil-Rod-Coil Triblock Copolymers2011Inngår i: Chemistry of Materials, ISSN 0897-4756, E-ISSN 1520-5002, Vol. 23, nr 17, s. 4045-4055Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A simple route to size-tunable nanoparticles from the self-assembly of degradable and electrically conductive coil rod coil triblock copolymers based on an aliphatic polyester and conducting species is presented. A series of coil rod coil triblock copolymers consisting of a middle aniline pentamer (AP) segment and two polycaprolactone (PCL) segments were easily synthesized by a combination of a ring-opening polymerization of CL initiated by an aniline dimer (AD) giving AD-PCL and an oxidative coupling reaction between the AD-PCL and p-phenylenediamine. This strategy avoids the multistep reaction used in previous work. The electroactivity of these copolymers was investigated by UV and cyclic voltammetry. The conductivity of the copolymers was dependent on the AP content and the conductivity mechanism of the triblock copolymers is discussed. Interestingly, these triblock copolymers can undergo self-assembly in selective solvent such as CHCl(3) as indicated by NMR and transmission electron microscope (TEM) observations. Dynamic light scattering (DLS) showed that the size of the nanoparticles was dependent on the molecular weight of the copolymers and on the oxidation state of the AP, The morphology of the nanoparticles was studied by TEM and SEM. These triblock copolymers and their size-tunable nanopartides with degradability and electroactivity offer new possibilities in biomedical applications, such as controlled drug delivery, biosensors, and cardiovascular and neural tissue engineering.

  • 43.
    Guo, Baolin
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Finne-Wistrand, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Albertsson, Ann-Christine
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Universal Two-Step Approach to Degradable and Electroactive Block Copolymers and Networks from Combined Ring-Opening Polymerization and Post-Functionalization via Oxidative Coupling Reactions2011Inngår i: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 44, nr 13, s. 5227-5236Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present a universal strategy for the facile synthesis of degradable and electroactive block copolymers and organogels (DEBCGs) based on aniline oligomers and polyesters in a two-step approach, here exemplified by the preparation of a series of DECBCGs based on aniline tetramer (AT) and poly(e-caprolactone) (PCL). Polyesters with an aniline dimer (AD) segment were first obtained by controlled ring-opening polymerization (ROP) of e-caprolactone initiated by the amine group of AD with or without 2,2-bis(epsilon-caprolactone-4-yl) propane (BCP). The postpolymerization modification via an oxidative coupling reaction between AD and a polyester was then used to form the electroactive segment AT in the copolymers or organogels. The molecular weight and conductivity of the block copolymers and organogels were controlled by the AT content. The chemical structure, electroactivity, and thermal properties of DEBCGs were investigated by FT-IR, NMR, SEC, UV, cyclic voltammetry, TGA, and DSC. Our general strategy for the synthesis of DECBCGs avoids the multiple step reactions and low efficiency involved in previous work.

  • 44.
    Guo, Baolin
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Finne-Wistrand, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Albertsson, Ann-Christine
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Versatile Functionalization of Polyester Hydrogels with Electroactive Aniline Oligomers2011Inngår i: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 49, nr 9, s. 2097-2105Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Functionalizing aliphatic polyester hydrogels with an aniline oligomer is a means of achieving electrically conductive and degradable hydrogels. To lower the aniline oligomer content while maintaining a high conductivity and to overcome the acidic degradation product from polylactide reported in our previous work, a series of electroactive and degradable hydrogels based on polycaprolactone (PCL) hydrogels and carboxyl-capped aniline pentamer (CCAP) were synthesized by a simple coupling reaction at room temperature. The reaction was carried out between the hydroxyl groups of hydroxyethylmethacrylate in a photopolymerized glycidyl methacrylate (GMA)-functionalized PCL-poly(ethylene glycol)-PCL degradable network and carboxyl group of CCAP, using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide as water-condensing agent and 4-dimethylamino-pyridine as catalyst. The electroactivity of the hydrogels was verified by cyclic voltammetry, which showed three pairs of redox peaks. The electrical conductivities and swelling ratios of these hydrogels were controlled by the CCAP content, the poly(ethylene glycol) molecular weight in the macromer, and the crosslinking density of the hydrogels.

  • 45.
    Guo, Baolin
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Sun, Yang
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Finne-Wistrand, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Mustafa, Kamal
    Albertsson, Ann-Christine
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Electroactive porous tubular scaffolds with degradability and non-cytotoxicity for neural tissue regeneration2011Inngår i: Acta Biomaterialia, ISSN 1742-7061, E-ISSN 1878-7568, Vol. 8, nr 1, s. 144-153Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Electroactive degradable porous tubular scaffolds were fabricated from the blends of polycaprolactone and a hyperbranched degradable conducting copolymer at different feed ratios by a solution-casting/salt-leaching method. Scaning electron microscopy (SEM) and microcomputed tomography tests indicated that these scaffolds had homogeneously distributed interconnected pores on the cross-section and surface. The electrical conductivity of films with the same composition as the scaffolds was between 3.4×10(-6) and 3.1×10(-7)Scm(-1), depending on the ratio of hyperbranched degradable conducting copolymer to polycaprolactone. A hydrophilic surface with a contact angle of water about 30° was achieved by doping the films with (±)-10-camphorsulfonic acid. The mechanical properties of the films were investigated by tensile tests, and the morphology of the films was studied by SEM. The scaffolds were subjected to the WST test (a cell proliferation and cytotoxicity assay using water-soluble tetrazolium salts) with HaCaT keratinocyte cells, and the results show that these scaffolds are non-cytotoxic. These degradable electroactive tubular scaffolds are good candidates for neural tissue engineering application.

  • 46.
    Hakkarainen, Minna
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Finne-Wistrand, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknologi, Polymerteknologi.
    Update on polylactide based materials2011 (oppl. 1)Bok (Annet vitenskapelig)
    Abstract [en]

    Today both scientists and industry are working to develop more environmentally friendly processes and materials. One of the most current topics is the development of energy and materials from renewable resources. There are fascinating developments in this area and advanced designed products can today be formed in an environmentally friendly way. Polylactide based materials are among the most promising synthetic renewable resource based materials. There is currently extensive research going on to develop polylactide based materials for different applications. These developments include both the use of new resources, development of more effective and environmentally friendly processes as well as modification and tailoring of material properties and degradability to broaden the application range.

    This book discusses recent developments in polylactide based materials including the whole spectra from different material modifications, applications and properties to new advanced synthesis procedures. When it comes to degradable materials, an important aspect is also the influence of different modifications on material properties, degradability and degradation products. The different chapters present new emerging processes and synthetic techniques as well as different material modifications obtained by copolymerization or blending with degradable or inert, natural or synthetic polymers. In addition advancements and developments in polylactide stereocomplexes, nanocomposites and biocomposites are presented. The book is of interest both from the basic and applied science point of view as it presents the latest trends and demonstrates the versatility and great potential of polylactide based materials. Hopefully the book can inspire the reader to further develop synthesis procedures or new ways to modify polylactide materials to broaden the properties to suit new applications.

  • 47. Idris, Shaza B.
    et al.
    Dånmark, Staffan
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Finne Wistrand, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Arvidson, Kristina
    Albertsson, Ann-Christine
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Bolstad, Anne Isine
    Mustafa, Kamal
    Biocompatibility of Polyester Scaffolds with Fibroblasts and Osteoblast-like Cells for Bone Tissue Engineering2010Inngår i: Journal of bioactive and compatible polymers (Print), ISSN 0883-9115, E-ISSN 1530-8030, Vol. 25, nr 6, s. 567-583Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The aim of this study was to evaluate the in vitro cytotoxicity and cytocompatibility of the developed aliphatic polyester co-polymer scaffolds: poly(L-lactide-co-epsilon-caprolactone) and poly(L-lactide-co-1,5-dioxepan-2-one). The scaffolds were produced by solvent casting and particulate leaching, and tested by direct and indirect contact cytotoxicity assays on human osteoblast-like cells and mouse fibroblasts. Cell morphology was documented by light and scanning electron microscopy. Viability was assessed by the MTT, neutral red uptake, lactic dehydrogenase and apoptosis assays. Extraction tests confirmed that the scaffolds did not have a cytotoxic effect on the cells. The cells grew and spread well on the test scaffolds with good cellular attachment and viability. The scaffolds are noncytotoxic and biocompatible with the two cell types and warrant continued investigation as potential constructs for bone tissue engineering.

  • 48. Idris, Shaza B.
    et al.
    Isine Bolstad, Anne
    Ibrahim, Saleh O.
    Dånmark, Staffan
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Finne Wistrand, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Albertsson, Ann-Christine
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Arvidsson, Kristina
    Mustafa, Kamal
    Global Gene Expression Profile of Osteoblast-Like Cells Grown on Polyester Copolymer Scaffolds2011Inngår i: Tissue Engineering. Part A, ISSN 1937-3341, Vol. 17, nr 21-22, s. 2817-2831Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    One of the principal goals in tissue engineering is to produce scaffold materials that will guide cells to differentiate and regenerate functional replacement tissue at the site of injury. Poly(l-lactide-co-1,5-dioxepan-2-one) [Poly(LLA-co-DXO)], a potential scaffolding material for bone tissue engineering, has high hydrophilicity. Previous in vitro studies using human osteoblast-like cells (HOBs) demonstrated greater cytocompatibility and enhanced osteogenic differentiation when HOBs were seeded onto Poly(LLA-co-DXO) compared to Poly(llactide) [P(LLA)] scaffolds. The aim of the study was to identify the gene expression profiles of HOBs obtained from alveolar bone and grown on Poly(LLA-co-DXO) biodegradable polymer scaffolds compared to P(LLA) one. Illumina HumanWG-6 v3.0 Expression BeadChips were used for the gene expression analysis. Several genes were found as differentially expressed at 24 h and at 21 days. Expression of genes related to cell adhesion, cytoskeleton, antiapoptosis, proliferation, and bone mineralization was influenced by adding the monomer 1,5-dioxepan-2-one to the l-lactide. Genes related to three biological pathways involving Integrin, Notch, and Ras were found to be upregulated. For selected genes, results were confirmed by quantitative reverse transcriptase– polymerase chain reaction. Further, calcium content analysis revealed a significant enhancement of calcium deposition on both tested scaffolds. This observation was confirmed by Von Kossa and Alizarin Red S staining. Findings of this study are relevant to a better understanding of the molecular mechanisms underlying the behavior of HOBs in bone regenerative procedure.

  • 49. Idris, Shaza Bushra
    et al.
    Arvidson, Kristina
    Plikk, Peter
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Ibrahim, Lah
    Finne-Wistrand, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Albertsson, Ann-Christine
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Bolstad, Anne Isine
    Mustafa, Kama
    Polyester copolymer scaffolds enhance expression of bone markers in osteoblast-like cells2010Inngår i: J BIOMED MATER RES PART A, ISSN 1549-3296, Vol. 94A, nr 2, s. 631-639Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In tissue engineering, the resorbable aliphatic polyester poly(L-lactide) (PLLA) is used as scaffolds in bone regeneration. Copolymers of poly(L-lactide)-co-(epsilon-caprolactone) [poly(LLA-co-CL)] and poly(L-lactide)-co-(1,5-dioxepan-2-one) [poly(LLA-co-DXO)], with superior mechanical properties to PLLA, have been developed to be used as scaffolds, but the influence on the osteogenic potential is unclear. This in vitro study of test scaffolds of poly(LLA-co-CL) and poly(LLA-co-DXO) using PLLA scaffolds as a control demonstrates the attachment and proliferation of human osteoblast-like cells (HOB) as measured by SEM and a methylthiazol tetrazolium (MTT) colorimetric assay, and the progression of HOB osteogenesis for up to 3 weeks; expressed as synthesis of the osteoblast differentiation markers: collagen type 1 (Col 1), alkaline phosphatase, bone sialoprotein, osteocalcin (OC), osteopontin and runt related gene 2 (Runx2). Surface analysis disclosed excellent surface attachment, spread and penetration of the cells into the pores of the test scaffolds compared to the PLLA. MTT results indicated that test scaffolds enhanced the proliferation of HOBs. Cells grown on the test scaffolds demonstrated higher synthesis of Col 1 and OC and also increased bone markers mRNA expression. Compared to scaffolds of PLLA, the poly(LLA-co-CL) and poly(LLA-co-DXO) scaffolds enhanced attachment, proliferation, and expression of osteogenic markers by HOBs in vitro. Therefore, these scaffolds might be appropriate carriers for bone engineering. (C) 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 94A: 631-639, 2010

  • 50. Kleinhans, C.
    et al.
    Vacun, G.
    Sun, Yang
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Haller, B.
    Kahlig, A
    Kluger, P. J.
    Finne-Wistrand, Anna
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik, Polymerteknologi.
    Walles, H.
    Hansmann, J.
    Evaluation of a perfusion bioreactor for efficient seeding and advanced culture conditions of large bone substitute materials addressing critical size defectsManuskript (preprint) (Annet vitenskapelig)
123 1 - 50 of 102
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