The aim of this thesis was to develop a bioactive and resorbable nanoscale composite
that mimics the properties of bone and will have the potential to regenerate bone. In
conventional composites, the polymer phase can mask the bioactive phase and often
degrades faster than the ceramic phase due to the weak interfacial bonding between
the polymer and ceramic. Here in this thesis an organic/inorganic nanocomposite
with stronger interfacial bonding between the two phases has been produced using
the sol-gel route.
Glasses containing SiO2 and CaO were used as the inorganic while the amino acid
poly-γ−glutamic acid (γ−PGA) was used as the organic. This is the first time an
inorganic/organic hybrid with enzymatically degradable polymer covalently
crosslinked to the inorganic has been produced. Several factors contributed to the
homogeneity of the nanocomposites; most important of all was the extent of
integration (homogeneity and phase miscibility) of the organic into the inorganic sol.
The main focus of this thesis was to synthesise this new material and to develop an
understanding of the nanoscale interactions of the two phases. The chemical structure
of the nanocomposites were characterised with Fourier transform infrared
spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (NMR) and the
nanostructure was characterised with scanning and transmission electron microscopy
(SEM and TEM). Bioactivity studies of the nanocomposites in simulated body fluid
(SBF) showed that the nanocomposites containing calcium were bioactive. Initial in
vitro cell response studies also showed that the nanocomposites were not toxic to
cells.
Nanocomposites were also foamed to create the first porous bioactive
inorganic/organic scaffolds with covalent bonding between the organic and
inorganic. Micro-computed tomography (μCT) was used to non-destructively image
and quantify the internal pore structure of the bioactive nanocomposite scaffolds.
The three-dimensional images of the scaffolds show that the nanocomposites have
large macropores with multiple connections between them giving a suitable pore
structure for tissue engineering
