As people around the world are living longer, we are seeing an increased demand for bone substitutes and graft for surgical treatment of orthopaedic conditions. More than two million bone grafting procedures to treat bone defects are performed annually worldwide, making it the second most frequent tissue transplantation.
Ideal graft material is autograft from the patient’s own source but the need for extra invasive procedures for sourcing of autograft material, sometimes resulting in donor site morbidity, presents significant clinical and economic disadvantages. Allograft or xenograft (using biochemical processed bone sourcing from deceased people or from animals) have always presented a risk of transmitted diseases and potential immunogenic reaction.
Synthetic bone substitutes, on the other hand, have the problem of effective osseointegration. There is an unmet need to address the limitations of bone substitute and to improve its bio-functional properties.
Nacre is a natural organic-inorganic component, which forms the shell of molluscs, such as pearl. This process shares an equal position with the animal and human bone formation as the only two natural bio-mineralisations ever discovered.
Inspired from an intriguing archaeological discovery of ancient Mayan skulls, which have perfectly fitting teeth made of nacre that radiographs showed had roots perfectly integrated into the surrounding bone, the marriage of bone and nacre has been highlighted as a promising solution to a shortage of bone implant materials.
A study at the University of Western Australia by Dr Rui Ruan and myself has shown that nacre possesses potent osteogenic properties and could potentially be suitable as a source for bone substitute material. Others have also shown that there are bioactive components in nacre that have potent osteogenicity to grow human bone.
Broome is the home of Australian South Sea Pearl production. Pearl production is the primary objective of the industry and a large quantity of shells, nacre, is produced as by-product.
The study discovered that nacre from Broome was rich in trace elements and free of any environmental contamination, and the best in enhancement of biomineralisation and bone formation. The team has subsequently developed a patented technology of using nacre to make a bone substitute named PearlBone.
In the preclinical study of a rabbit critical bone defect model, PearlBone displayed better bone healing efficacy when compared to the most commonly used bone substitute, hydroxyapatite.
A Broome-based biotech company, Marine Biomedical, has now been established based on the PearlBone technology. The company will use nacre from Broome to manufacture PearlBone under the good manufacture practice (GMP) guidelines to obtain FDA market authorisation of the product for orthopaedic use. This is the first medical manufacturing company set up in Kimberley region and will shine a light on the local pearling industry.
Key messages
- An ageing population sees increased demand for bone grafting
- Autograft is ideal but there is a need for other options
- Nacre can be converted into a bone substitute material with enhanced biological performance.
Author competing interests – Author is the inventor of the product described