Bioresorbable copolymers with tailored properies: innovative materials för soft tissuel engineering
2006 (English)Doctoral thesis, comprehensive summary (Other academic)
The emerging need for new synthetic materials for soft tissue engineering applications encourages the search for innovative polymers having interesting properties. Ring-opening polymerization of lactones and lactides initiated by tin alkoxides has received particular attention due to the versatility of the method for building up well-defined biodegradable structures. The controlled reactions together with a careful choice of comonomers and copolymer composition make it possible to create materials with desired molecular architecture and properties.The aim of the work described in this thesis was to design aliphatic bioresorbable copolymers with new structures and controlled properties for potential application in soft tissue engineering. The first part of the work was focused on the surface properties of the materials synthesized for biomedical application. Solution-cast film triblock copolymers of L-lactide (LLA) and 1,5-dioxepan-2-one (DXO), subjected to thermal treatment have been studied. The effects of molecular weight, polymer composition, cooling rate, and casting solution concentration on the nanostructure surface morphology and topography have been investigated by atomic force microscopy (AFM). The surface characterization of the annealed triblock copolymers revealed well-defined fiber features formed as a result of a melt-induced micro-phase separation during crystallization. The dimensions and shape of the formations could be related to the copolymer composition and annealing conditions, and this makes it possible to create controlled and well-defined surface structure. The results of cell adhesion studies on annealed triblock copolymers indicate that these materials favor fibroblast growth and spreading, which makes them promising candidates for applications as bioresorbable membranes.In the next stage of the work, linear and network copolymers of ε-caprolactone (CL) and DXO with a controlled composition and controlled hydrophilicity have been synthesized. The molar fraction of DXO in the copolymers affected their mechanical, thermal and surface properties. The hydrophilicity was tailored by changing the monomer composition in the copolymers. The AFM measurements on the linear copolymers showed that short fibrillar structures were formed upon crystallization from the melt. The supple CL-DXO networks were easy to cast and could easily be removed from the mould surface, so that it is possible to use this material for embossing procedures without the risk of damaging the surface pattern during removal from the mould.
Place, publisher, year, edition, pages
Stockholm: KTH , 2006. , 70 p.
Trita-FPT-Report, ISSN 1652-2443 ; 2006:18
poly(1, 5-dioxepan-2-one), poly(ε-caprolactone), poly(L-lactide), poly(trimethylene carbonate), triblock, network, cyclic tin alkoxide, controlled coordination-insertion ring-opening polymerization, thermoplastic elastomers
IdentifiersURN: urn:nbn:se:kth:diva-4042ISBN: 91-7178-378-4OAI: oai:DiVA.org:kth-4042DiVA: diva2:10528
2006-06-16, Aal K2, Teknikringen 28, Stockholm, 10:00 (English)
Dijkstra, Pieter, Professor
QC 201006292006-06-072006-06-072010-06-29Bibliographically approved
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