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- Yang, L., et al.
(författare)
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Biomimetic calcium phosphate coatings on recombinant spider silk fibres
- 2010
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Ingår i: Biomedical Materials. - : Institute of Physics (IOP). - 1748-6041 .- 1748-605X. ; 5:4
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Tidskriftsartikel (refereegranskat)abstract
- Calcium phosphate ceramic coatings, applied on surfaces of metallic and polymeric biomaterials, can improve their performance in bone repair and regeneration. Spider silk is biocompatible, strong and elastic, and hence an attractive biomaterial for applications in connective tissue repair. Recently, artificial spider silk, with mechanical and structural characteristics similar to those of native spider silk, has been produced from recombinant minispidroins. In the present study, supersaturated simulated body fluid was used to deposit calcium phosphate coatings on recombinant spider silk fibres. The mineralization process was followed in time using scanning electron microscopy equipped with an energy dispersive x-ray (EDX) detector and Raman spectroscope. Focused ion beam technology was used to produce a cross section of a coated fibre, which was further analysed by EDX. Preliminary in vitro experiments using a culture of bone marrow-derived human mesenchymal stem cells (hMSCs) on coated fibres were also performed. This study showed that recombinant spider silk fibres were successfully coated with a homogeneous and thick crystalline calcium phosphate layer. In the course of the mineralization process from modified simulated body fluid, sodium chloride crystals were first deposited on the silk surface, followed by the deposition of a calcium phosphate layer. The coated silk fibres supported the attachment and growth of hMSCs.
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- Yang, Sun, 1983-
(författare)
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The role of computer-aided design and surface chemistry on Cell-scaffold interactions
- 2012
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Cell interactions and cell response to three dimensional scaffolds based on poly(L-lactide-co-1,5-dioxepan-2-one) [poly(LLA-co-DXO)] and poly(L-lactide-co-e-caprolactone) [poly(LLA-co-CL)] wereimprovedstudiedby increasing surface hydrophilicity and by using computer-aided scaffold design. Different amounts of Tween 80 (3, 10, 20 wt%) were mixed with the copolymer and it was found that the water contact angle decreased significantly with the amount of Tween 80. The contact angle of poly(LLA-co-CL) and poly(LLA-co-DXO) decreased from 85° to 35° and 75° to 17° respectively by using 3 wt% Tween 80. Samples with 20% Tween 80 had a water contact angle of 15°. In addition, stiffness decreased when the amount of Tween 80 was increased and thermal properties changed significantly when the amount of Tween 80 was higher than 3 wt%. Cell response was evaluated using three dimensional scaffolds and homogenous films. It was clear in this study that a high amount of Tween 80 resulting in a very low water contact angle had a toxic effect and negative influence on attachment and spreading of bone marrow stromal cells (hBMSC), while a moderate water contact angle had a positive influence on hBMSC differentiation, with significantly higher expression of Runx2 and osteocalcin. A three-dimensional fiber deposition (3DF) technique was employed to make layer-based scaffolds in a reproducible fashion. The 3DF scaffolds manufactured in this way showed enhanced mechanical properties, with E-modulus ranging from about 3 to 5 MPa in tensile strength and 0,22 to 0,29 MPa in compression tests, compared with scaffolds formed by a salt leaching method which had values of 1 and 0,03 MPa, respectively. Degradation during printing was obvious but the decrease in molecular weight did not influence thermal properties or stability of the 3DF structure. After 1 and 7 days of in vitro cell culture fluorescence staining and scanning electron microscopy showed homogeneous distribution of human osteoblasts (hOBs) on the scaffolds. The 3DF technique thus appears to be a promising method for fabrication of computer designed scaffolds as the scaffold structure is reproducible and their design can be controlled to achieve tailor made products for clinical applications.
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