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Title: Development of poly (3-hydroxybutyrate) (P(3HB))/bioactive glass composite system for biomedical applications
Author: Misra, Superb K.
ISNI:       0000 0004 2670 2115
Awarding Body: Imperial College London
Current Institution: Imperial College London
Date of Award: 2009
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P(3HB) was produced from a novel gram-positive micro-organism (Bacillus cereus SPV) using biotechnology routes based on a 14 L fermentation strategy. 45S5 Bioglass (BG) particles of micrometer (<5 μm) and nanometer (<50 nm) sizes were added in different concentrations (5-30 wt%) to the P(3HB) matrix to prepare composites (films and foams) using the solvent casting/particulate leaching technique. Addition of nanosized bioactive glass particles increased the Young's modulus (up to 57%), enhanced the hydrophilicity (up to 58%), improved the total protein adsorption (up to 186%) and induced nanostructured topography on the surface of the composites. The in vitro degradation study in simulated body fluid (SBF) showed the P(3HB)/BG composites to be highly bioactive and to exhibit improved water absorption behaviour. Cytocompatibility studies using MG-63 human osteoblasts revealed the P(3HB)/BG composites to be a suitable substrate for cell attachment, proliferation and differentiation. Implanting P(3HB)/BG composites subcutaneously in rats (up to 2 weeks) provoked a foreign body and a non-toxic response. The presence of BG in the polymeric matrix also showed a strong antibacterial effect on the growth of S. aureus. Inclusion of Vitamin E i.e. a biological antioxidant, significantly improved the wettability (up to 22%), increased the total protein adsorption (up to 300%) and rendered the P(3HB)/BG composites suitable for cell growth. The presence of MWCNTs (2-7 wt%) induced electrical conductivity in the P(3HB)/BG composites without hindering the bioactivity. The presence of MWCNTs in P(3HB)/BG composites in high concentration (>2 wt%) caused MG-63 osteoblast cell death, whereas in low concentrations MWCNTs increased the cell proliferation. Overall, the novel composites developed in this project represent a very attractive group of materials for bone tissue engineering applications.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available