Novel nanocomposite materials for artificial bone implants
The aim of this project is to develop a series of novel nanocomposite materials for artificial bone implants. Such nano-structured organic/inorganic composites will be particularly useful in load bearing bone grafts. Among the approximately 90 million human fractures suffered in Australia every year, about 15% are difficult to heal. These cases are compounded by defects in load-bearing bone, for which there is no effective therapy. Current artificial materials are either too brittle (ceramics), too flexible (polymers), do not degrade (metals), or are difficult to form into the required porous structures.
The materials developed will contain nano-sized hydroxyapatite, and a suitable biodegradable polymer (eg, the polyhydroxybutrate or chitosan) as the organic phase. PHBV and chitosan have good mechanical properties and degrades slowly in the body, allowing for load-bearing capacity to be maintained over the healing period. Hydroxyapatite exists in living bone and can be easily resorbed and re-deposited. It is our aim to develop nanocomposites with the following key features: a high volume fraction of hydroxyapatite, nano-sized hydroxyapatite plates and other shapes with high aspect ratios, a discrete, even dispersion of aligned hydroxyapatite nanoparticles in the processed material. Moreover, the incorporations of suitable biological signalling molecules to enhance the regeneration of natural tissue within such implants, ‘Osteo-induction’, is also being investigated.
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