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Polyhydroxyalkanoates (PHAs) are a family of biocompatible and biodegradable polymers produced from renewable sources by many bacteria. They possess a wide range of material properties, which may be modulated by blending to achieve a suitable biomaterial. Where the polymers in a blend have been reported as immiscible, the phase separation may be ameliorated by the addition of Single Wall Carbon Nanotubes (SWCNT). The aim of this work was to produce a biodeuterated polymer to characterise phase separation in a blend, and determine the effect of SWCNT on polymer miscibility. Electrical and thermomechanical properties of the bionanocomposite films were investigated, and growth of olfactory ensheathing cells (OECs) on the films was assessed to indicate biocompatibility. Biodeuterated Polyhydroxyoctanoate (PHO) was produced from growth of Pseudomonas oleovorans on deuterated carbon source, and characterisation by 1H, 2H and 13C NMR spectroscopy showed partial deuteration at the α- and β-carbon atoms, while the side chain was fully deuterated. The biodeuterated polymer was blended with Polyhydroxybutyrate (PHB) into a solvent-cast film, and Infrared microspectroscopy (IRM) showed phase separation in cross-sections of the equimolar blend. Addition of SWCNT displayed some of the hypothesised improvement in miscibility of polymer phases compared to the SWCNT-free blend, however the mechanical properties of tensile strength and elongation at break did show any improvement over the blend, and deteriorated at loadings of 5 wt. % SWCNT and above. Increased conductivity (exceeding the electrical percolation threshold) was observed at 1 wt. % SWCNT loading in the equimolar blend, and preliminary studies showed that this bionanocomposite could support growth of olfactory ensheathing cells (OECs), indicating its suitability as a scaffold for neural cell regrowth. Biodeuteration was therefore shown to be a useful tool for characterising microbial synthesis and polymer miscibility, and the addition of SWCNT may be used to extend the range of future applications of these biopolymers.

The focal point of this thesis was to fabricate and characterize a nanofibrous scaffold with added functional particulates of monetite, a compound in the calcium phosphate family, using the electrospinning process. The material was developed to be tested as a potential bone tissue engineering scaffold. PLA and monetite were chosen for the development of the bionanocomposite because of their biocompatibility and biodegradability. The calcium present in the monetite is useful to enrich the environment for compatibility with bone extracellular matrix (ECM). Parameters influencing the electrospinning process were varied to find the optimum conditions for producing uniform fibers.Using characterization methods such as scanning electron microscopy (SEM), X-ray diffraction (XRD), and scanning transmission electron microscopy (STEM) the fiber morphology, chemical composition, and dispersion of monetite particles in the fibers were determined. Higher ratios of monetite to PLA in the fibers significantly affected the electrospinning process and the morphology of the fibers; lower monetite contentproduced nanofibers with a reduction in beads. Particles of monetite were randomly dispersed in the fiber matrix.The fibers that showed optimal characteristics for tissue culture were then tested for biocompatibility and osteoconductivity. A series of tests were undertaken including soaking in Tas-Simulated Body Fluid (t-SBF) [1] to form apatite coating, degradation in PBS and complete media, and cell culture testing. Positive results were obtained during all biocompatibility testing including apatite coating, pore formation during degradation, and cell infiltration into the fibrous scaffold material. The design and initial biological studies on this bone tissue engineering scaffold proved to have positive results.