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Development of injectable material technology for spinal applications
2009 (English)Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
Abstract [en]

Degeneration of the intervertebral disc constitutes one of the major causes of low back pain in adults between 20 and 50 years old. Improved reliability and a minimum of postoperative complications are the current issues for the development of new methods for treating degenerated intervertebral discs. The aim is to develop a minimally invasive procedure for the implantation of materials that stabilize the tissues around the injury zone, transfer the loads, and eventually resorbs while the tissues are regenerated. Injectable, self-curing, degradable composites were prepared for this purpose. A polymeric matrix was synthesized via ring-opening copolymerization of D,L-lactide and epsilon-caprolactone using 1,4-butanediol as co-initiator. The feed relative amounts were 5:5:1 respectively. Low molecular weight oligomers were produced. These hydroxyl end-capped oligomers were later converted to acrylic-terminated oligomers in order to make them crosslinkable. Porous beta-TCP and calcium carbonate were manually incorporated into the prepolymers. Different formulations including 0, 5 and 30 wt% filler were prepared for testing. The crosslinking was done at room temperature by the incorporation of benzoyl peroxide and N,N-dimethyl-p-toluidine into two separate pastes which reacted after mixing them together in equal amounts. The structure of the prepolymers was confirmed by 1H NMR spectroscopy and the number average molar mass was calculated. The calcium carbonate particles were characterized by XRD and showed to be pure calcite. Most of the composites exhibited a curing time of 20 minutes. The cut surface of the composites was examined via SEM and a good dispersion of the ceramic fillers was observed. The porous beta-TCP particles also showed good mechanical attachment to the matrix due to penetration of the polymer into the porous structure. In-vitro degradation test showed that the composites containing beta-TCP degraded easily whereas the composites containing CaCO3 were more likely to absorb water. It was found that these properties can be controlled by changing the particle size, morphology and the type of fillers. The incorporation of fillers also increased both the elasticity modulus and the maximum compressive strength of the composites. These materials proved to have potential for long term intervertebral disc replacements and regenerative scaffolds due to their low degradation rates, water uptake capacity and Young’s modulus similar to that of the tissues found in the intervertebral disc.

Place, publisher, year, edition, pages
Keyword [en]
Technology, composites, degradable polymers, injectable, resorbable, ceramics, intervertebral disc
Keyword [sv]
URN: urn:nbn:se:ltu:diva-49961ISRN: LTU-PB-EX--09/094--SELocal ID: 742eec4e-a83d-4eb9-badc-556b6cda388fOAI: diva2:1023314
Subject / course
Student thesis, at least 30 credits
Educational program
Materials Engineering, master's level
Validerat; 20101217 (root)Available from: 2016-10-04 Created: 2016-10-04Bibliographically approved

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