Associate Professor Michael Mucalo (centre of photo) in the School of Science at the University of Waikato are developing human biomedical applications from bovine bone.
His research has centred on the use of animal-derived bone for bone regenerative healing, namely the use of cancellous bone normally sourced from the bovine condyle as a bone xenograft. Such bone is plentiful in New Zealand owing to the country’s large cattle populations on dairy farms and to the fact that most of the bone is used for low-value applications such as fertilisers. The research provides a value-added application for this bone and has an additional appeal for export in that New Zealand is BSE-free. Other sources of mineral material such as from seashells have also been researched.
Initial work focused on the development of a method to process the raw bovine bone into what was effectively hydroxycarbonate apatite with retention of the osseous, porous framework, which, when clinically implanted into sheep and trialled in companion animals, proved to be osteoconductive. Subsequent work focused on sintering of the cancellous bone to form crystallised hydroxyapatite with the porous framework intact. Sintering causes major losses in the strength of the bone hence Associate Professor Mucalo’s group developed processes for infiltrating the sintered bone with natural organic macromolecules like chitosan or synthetically produced biocompatible polymers like polycaprolactone. This effectively served to replace what was once collagen (removed via sintering) with another material that was still biocompatible but without the potential issues associated with collagen, such as BSE, even though New Zealand has no known instances of these prions. The removal of collagen and infiltration with other materials was done to increase user acceptability of these materials.
This work was done collaboratively with Associate-Professor George Dias at the University of Otago with whom current interests involve projects into forming substituted hydroxyapatites from cattle bone. Other interests of Associate-Professor Mucalo in the biomedical sphere include controlled release drug delivery and gels.