Investigation of bacterial attachment on hydroxyapatite-coated titanium and tantalum

Titanium and tantalum have been widely employed in many load- bearing orthopaedic applications due to their excellent strength and corrosion resistance. The bio-function properties of titanium and tantalum can be enhanced to improve the healing process after implantation by incorporating a bioactive coating onto their surfaces. For this purpose, thin films of 200 nm thick silicon dioxide (SiO2) and 2 mu m thick hydroxyapatite (HA) were deposited onto titanium and tantalum surfaces using electron beam evaporation and magnetron sputtering, respectively. The surface morphology, elemental composition and crystal structure of HA-SiO2 coated titanium and tantalum were characterised using scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffractometry. Pseudomonas aeruginosa and Staphylococcus aureus strains were used to investigate the bacterial attachment onto these surfaces. The HA thin films deposited onto titanium and tantalum surfaces were homogenous. The desirable crystalline phase of HA was also identified on the titanium and tantalum surfaces. Bacterial attachment results indicate that HA-SiO2 coated surfaces were less preferable for the adhesion of bacteria compared to the non-coated surfaces.