eTheses Repository

# Silver, magnesium and zinc substituted hydroxyapatite for orthopaedic applications

Synthetic hydroxyapatite (HA) has been widely used for biomedical applications, in particular as a bone substitute and coating for implants, due to its similarity to the inorganic component of human bone. The aim of this study was to incorporate three divalent cations (silver, zinc and magnesium) into the hydroxyapatite structure via a wet chemical precipitation method to enhance its antibacterial properties, to avoid the need for the use of antibiotics. Material characterisation techniques such as XRD and Raman Spectroscopy confirmed that these ions were substituted within the crystal structure of HA, though did not follow the expected reaction stoichiometry and substitution ratios. HA material properties, such as crystal size, crystallinity and solubility were shown to change after ion substitution. Metal-substituted HA showed varying strengths of antibacterial properties against two bacterial strains of $$E$$.$$coli$$ and $$S$$.$$epidermidis$$, which was attributed to different type of ions and substitution ratios and also different release profiles from the solid phase to the culture medium. The results from cell biological studies confirmed that the rate of osteoblast cell proliferation and cell differentiation were improved after cells being incubated with disks of substituted HA.