Hydroxyapatite as a bioceramic
In some types of bone reconstruction operations, pieces of bone harvested from some other location in the body, such as the pelvis, are used to replace the damaged or diseased bone. This is a painful procedure and recuperation can be slow and protracted.
What are bioceramics and biomaterials?
Dr Michael Mucalo is a senior lecturer in chemistry at the University of Waikato. One of his research interests is in the bioceramics field, and in this video, Michael explains the meaning of terms commonly used in this field. He clarifies the difference in meaning between ‘bioceramic’ and ‘biomaterial’ as well as between ‘bioinert’ and ‘bioactive.
Dr Michael Mucalo from the University of Waikato Chemistry Department in association with Dr George Dias from the University of Otago have been researching an alternative method. This involves using bovine hydroxyapatite as a bioceramic in place of the harvested bone.
Cow bone research
University of Waikato’s Dr Michael Mucalo has been conducting research into the possibility of using cow bone as a suitable bone substitute. In this video, Michael gives the rationale for his research and explains how the body can colonise and absorb the bone substitute into healthy bone tissue.
The hydroxyapatite bioceramic is made from the spongy bone material from a cow femur.
Small cubes are cut out and then subjected to chemical and physical processes that remove all the fat and protein. The remaining material is then heated to 1,000°C for several hours. What remains is a sterile, open 3D mineral shell of pure hydroxyapatite.
Small cubes or cylinders of this material can be grafted into the damaged living bone site. Over a period of time, new bone develops and grows in and around the implant. Eventually, successful repair of the damaged bone is achieved.
Hydroxyapatite bioceramic at various stages of processing
Hydroxyapatite bioceramic is made from the spongy bone material from a cow femur. Small cubes are cut out and then subjected to chemical and physical processes.
At present, this novel method has only been tested on animals such as sheep and dogs. The results have been promising, and human clinical trials are not too far away.
One drawback of this method is that it can only be used in non load-bearing settings. However, Dougal Laird, one of Dr Michael Mucalo’s PhD students, is investigating the infiltration of the hydroxyapatite implant with other materials to improve its strength and bioactivity.
Dougal Laird’s research
One of the problems with cow bone hydroxyapatite is that it lacks strength. In this video, Dougal Laird, a University of Waikato PhD student, outlines his bioceramic research project, which involves infiltrating the sintered cow bone with certain organic materials in the hope that the strength of the implant can be improved.
Nature of science
Scientific research is frequently conducted across disciplines in a collaborative and co-ordinated way. Dr Michael Mucalo’s research project is a typical example of this.
Related content
What are minerals? A mineral is an element or chemical compound, normally crystalline, that is found in rocks or as natural deposits in the Earth’s crust. Minerals are often used in the production of ceramics. This resource investigates the structural features and physical properties of common minerals and the mineral content of rocks is also considered.
Bone and tooth minerals The minerals found in human teeth and bones that give them their hardness and strength belong to a mineral family known as biological apatites. The biological apatites are forms of calcium hydroxyapatite, which has the formula Ca10(PO4)6(OH)2. This resource looks at the chemical and physical properties of this mineral as found in tooth enamel, dentine and bone. Bioceramics are used to replace these hard tissues in the body.
Activity ideas
Bone minerals: investigate how bone strength varies with its mineral content and the solubility of bone minerals in neutral and acidic solutions.
Bone strength: create artificial bones made of paper to compare the relative strength of solid bones with hollow bones.
