Bone grafting improvements with the help of sea coral

(Press-News.org) Contact information: Michael Bishop
michael.bishop@iop.org
01-179-301-032
Institute of Physics
Bone grafting improvements with the help of sea coral Sea coral could soon be used more extensively in bone grafting procedures thanks to new research that has refined the material's properties and made it more compatible with natural bone.

By partially converting calcium carbonate―found in the exoskeleton of sea coral―into coralline hydroxyapatite (CHA), the refined material, called coralline hydroxyapatite/calcium carbonate (CHACC), has been shown to 'considerably improve' the outcome of bone grafts in 16 patients.

The results of the small clinical study, which have been published today, 29 November 2013, in IOP Publishing's journal Biomedical Materials, showed that bone healing was observed in each of the patients after four months and that the CHACC had fully biodegraded after two years.

CHA derived from sea coral has been used for many years as a successful bone graft material; however, its use has been limited to specific bones because it does not fully biodegrade.

The corresponding author of the research Zhidao Xia from Swansea University said: "Our methods have considerably improved the outcome of bone grafts by using the partial conversion technique, in which the biodegradable composition from natural coral is reserved. It works in a very similar way to commercially available CHA for conductive bone regeneration, but the better biodegradation properties are compatible with the host tissue's natural bone turnover process.

"When biomaterials do not biodegrade and remain in skeletal tissue, they may continuously cause problems in the host. In extreme conditions, it is possible that the different mechanical properties of the artificial bone graft may cause a re-fracture or become a source for bacterium growth in infection."

CHACC could become a promising alternative to an autograft, which uses pieces of bone from another part of the patient's body to regrow new bone in the injured area. Besides only having a limited stock, an autograft can cause discomfort, pain and long-term impairment in the area that the bone is taken from.

In their study, the researchers, from the UK and China, harvested sea coral from South China and partially converted the calcium carbonate into CHA to form CHACC.

According to the paper, the CHACC composition, which contains 15 per cent of CHA in a thin layer around the calcium carbonate, has the strong, porous structure that has made CHA commercially successful, but contains significantly improved biodegrading properties to support natural bone healing.

In their study, the researchers constructed CHACC and tested its physical and chemical properties using a number of microscopic and spectroscopic techniques. The CHACC was then mixed with human mesenchymal stem cells and implanted subcutaneously in mice for 10 weeks. The results showed that new bone formation was visible on the surface of the CHACC.

In a preliminary clinical study, 16 patients (11 male and five female) with a range of four different bone defects were surgically implanted with CHACC. Results showed there was clinical bone healing four months after surgery and the majority of the implanted CHACC degraded after 18 to 24 months in each patient.

Bone remodelling can be a complex and slow process by which old bone is continuously replaced by new bone tissue. In the case of fracture healing, the complete remodelling phase can take between three and five years depending on the individual, so a synthetic bone graft must biodegrade within a time window that relates to the natural bone remodelling cycle.

The researchers acknowledge that there is some way to go until the material can match the benefits of an autograft and be used on the several million people worldwide who undergo bone grafting procedures each year.

"Although our study has provided promising results, the CHACC material does not contain a bone organic matrix, living cells and the ability to induce, rather than conduct, new bone formation. Therefore, our future work is to combine controlled growth factor delivery and stem cell technology in order to develop an even better solution for bone graft materials." continued Xia.

### From 29 November 2013, this paper can be downloaded from http://iopscience.iop.org/1748-605X/8/6/065007/article

Notes to Editors

Contact

1. For further information, a full draft of the journal paper or contact with one of the researchers, contact IOP Press Officer, Michael Bishop: Tel: 0117 930 1032 E-mail: michael.bishop@iop.org

For more information on how to use the embargoed material above, please refer to our embargo policy.

IOP Publishing Journalist Area

2. The IOP Publishing Journalist Area gives journalists access to embargoed press releases, advanced copies of papers, supplementary images and videos. In addition to this, a weekly news digest is uploaded into the Journalist Area every Friday, highlighting a selection of newsworthy papers set to be published in the following week.

Login details also give free access to IOPscience, IOP Publishing's journal platform.

To apply for a free subscription to this service, please email Michael Bishop, IOP Press Officer, michael.bishop@iop.org, with your name, organisation, address and a preferred username.

Characterisation of a biodegradable coralline hydroxyapatite/calcium carbonate composite and its clinical implementation

3. The published version of the paper 'Characterisation of a biodegradable coralline hydroxyapatite/calcium carbonate composite and its clinical implementation' Kun Fu et al 2013 Biomed. Mater. 8 065007 will be freely available online from 29th November 2013. It will be available at http://iopscience.iop.org/1748-605X/8/6/065007/article

Biomedical Materials

4. Biomedical Materials (BMM) publishes original research findings that contribute to our knowledge about the composition, properties, and performance of materials for tissue engineering and regenerative medicine.

IOP Publishing

5. IOP Publishing provides a range of journals, magazines, websites and services that enable researchers and research organisations to reach the widest possible audience for their research.

We combine the culture of a learned society with global reach and highly efficient and effective publishing systems and processes. With offices in the UK, US, Germany, China and Japan, and staff in many other locations including Mexico and Russia, we serve researchers in the physical and related sciences in all parts of the world.

IOP Publishing is a wholly owned subsidiary of the Institute of Physics. The Institute is a leading scientific society promoting physics and bringing physicists together for the benefit of all. Any profits generated by IOP Publishing are used by the Institute to support science and scientists in both the developed and developing world. Go to ioppublishing.org.

The Institute of Physics

6. The Institute of Physics is a leading scientific society. We are a charitable organisation with a worldwide membership of more than 50,000, working together to advance physics education, research and application. We engage with policymakers and the general public to develop awareness and understanding of the value of physics and, through IOP Publishing, we are world leaders in professional scientific communications. Go to http://www.iop.org