Methods: nHA paste was prepared using a wet precipitation method based on Prakash et al. [1]. The nHA suspension was dried in an oven at 60 °C until a paste consistency was obtained. A silver-doped nHA paste was prepared in the same manner by dissolving 2 mol.% silver nitrate in the calcium suspension. X-ray diffraction (XRD), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and transmission electron microscopy (TEM) were carried out to analyse the materials produced. The antibacterial activities of the pastes against Staphylococcus aureus and Pseudomonas aeruginosawere analysed.
Results: XRD, ATR-FTIR and TEM results displayed the formation of nHA in all the samples produced. High temperature sintering caused the partial decomposition of the silver-doped nHA into β-tricalcium phosphate. The agar diffusion model demonstrated that only the silver-doped nHA paste was effective against Staphylococcus aureus and Pseudomonas aeruginosa. This suggested that the silver was highly likely to be responsible for this effect, and that the silver ions were also diffusible.
Conclusion: A silver-doped nHA paste which possessed antibacterial activity was successfully produced using a wet precipitation method. This paste has great potential to reduce bone infection rates and encourage optimal bone healing.
Acknowledgments: The authors would like to acknowledge Ceramisys Ltd. and EPSRC (EP/I501657/1) for funding this project.
References: [1] Prakash K. H. et al. Langmuir. 2006, 22, 11002.