Abstract
An experimental study was performed in order to investigate methods of preparation and mechanical properties of a potential bone graft substitute. This new composite material consists of porous hydoxyapatite coated with oxidised cellulose.
Porous hydoxyapatite has excellent osteoconductive properties and promising strength characteristics. Drawbacks include its lack of osteoinductive properties and its brittle nature. Oxidised cellulose can be functionalised to provide binding sites for proteins, drugs and cells, which would allow for increased osteoinductive activity. It has good tensile strength. By creating a composite of these two substances, it was proposed that a graft substitute could be created.
Hydroxyapatite samples were formed by processing and sintering bovine cancellous bone. A method was devised by which cellulose was brought into solution and infiltrated into hydoxyapatite samples. The cellulose was then regenerated (cured) and oxidised.
Infrared spectrometry confirmed the desired chemical reactions took place and that oxidised cellulose was formed. Scanning electron microscopy confirmed that the three-dimensional structure of the hydroxyapatite was satisfactorily coated. Crush testing showed that infiltrated samples were less brittle and more likely to hold their shape than control samples.
Further development and testing is required to assess this composite material for its biological activity and potential as a bone graft substitute.
Correspondence should be addressed to Associate Professor N. Susan Stott at Orthopaedic Department, Starship Children’s Hospital, Private Bag 92024, Auckland, New Zealand
