Sophie Cox, a doctoral researcher at WMG undertook an internship with Ceram, an independent materials technology company. Sophie is now employed as a Project Engineer on the High Value Manufacturing Catapult project at WMG and is using the knowledge of materials she developed during her PhD to support Catapult projects.
Sophie joined Ceram’s biomaterials innovation team to further her commercial understanding of the synthesis and testing of medical materials, specifically hydroxyapatite (HA). HA is a popular bone replacement material because it is chemically and crystallographically similar to native bone mineral. It is used in a number of clinical applications, including inert implant coatings, void or defect fillers, bone grafts, hard tissue scaffolds and drug delivery entities.
Control of chemical (e.g. crystallinity) and physical (e.g. particle size) characteristics of HA is important as such properties ultimately define in-service performance e.g. bioactivity and mechanical strength.
During the internship Sophie investigated and compared a range of common HA synthesis methods according to a pre-defined set of criteria that culminated with a white paper published on Ceram’s website. Furthermore, utilising Ceram’s state-of-the-art reaction vessel Sophie was able to produce HA under a range of controlled conditions to further understand the influence of these parameters on the characteristic properties of the resultant product. Further investigation was completed at WMG as part of Sophie’s doctoral thesis.
In addition to the synthesis of HA, Sophie also investigated the potential to improve a standardised testing procedure during her time at Ceram. Vigorous regulatory tests are employed in the medical device industry, which are generally very expensive and time consuming. In contrast, ISO23317:2007 ‘implants for surgery – in vitro evaluation for apatite forming ability of implant materials’ offers a relatively quick and cheap assessment of material bioactivity. However, the procedure (an examination of new HA deposition following sample immersion in simulated body fluid) does not enable the bioactivity of different samples to be quantitatively distinguished.
To assess the feasibility of using advanced x-ray diffraction analysis to quantify HA deposition, Bioglass disc samples were immersed in simulated body fluid in accordance to ISO23317:2007 for up to 28 days. The experimental results collected by Sophie were analysed at Ceram and presented in a scientific paper.