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Title: Bioglass®-derived glass-ceramic scaffolds for bone tissue engineering
Author: Chen, Qizhi
ISNI:       0000 0004 2737 5283
Awarding Body: Imperial College London
Current Institution: Imperial College London
Date of Award: 2007
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Tissue engineering demands a highly porous scaffold that can replace mechanical function temporarily and degrade at rates appropriate to tissue regeneration, in addition to biocompatibility and cell delivering ability. Unfortunately this is not the way that the existing biocompatible materials usually behave in a biological environment. Mechanically stable materials tend to be bioinert, while degradable materials are generally fragile. Therefore, a novel materials science strategy is required to address the issue. In this study, 3D highly porous, mechanically competent scaffolds have been fabricated for the first time from 45S5 Bioglass® by a replication technique. Their mechanical strength is conferred by extensive densification of the foam struts and formation of fine crystalline particles during the sintering stage. Poly(D,L-lactic acid) (PDLLA) was incorporated as a coating onto the Bioglass®-based glass-ceramic foams by dipping them in PDLLA-dimethyl carbonate (DMC) solution. The work of fracture of the Bioglass®-based foams was significantly improved by the PDLLA coating. Surface silanization was applied to the scaffolds to improve cell attachment. A significant discovery is that the mechanically strong crystalline phase can transform into a degradable amorphous phase in a highly porous scaffold under biological conditions (tested in contact with simulated body fluid), which does not usually occur in dense materials at the body temperature. Moreover, it was found that the kinetics of the phase transformation, which was influenced by the sintering conditions and surface functionalisation conditions, was tailorable. This phase transformation effectively combines mechanical strength (associated with the crystalline phase) with tailorable biodegradability (associated with the amorphous phase) in one scaffold. In vitro cell culture demonstrated that cell proliferation was not hampered by crystallisation. The present work shows that the goal of an optimised scaffold for bone tissue engineering that provides mechanical support temporarily and biodegrades in a controlled manner upon implantation is achievable with the developed Bioglass®-based glass-ceramic scaffolds.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available