Zinc-substituted hydroxyapatite

Abstract Biological apatite differs in composition when compared with synthetic hydroxyapatite (HA). The mineral component of teeth and bone is referred to as biological apatite. As compared with synthetic HA, it contains additional ions. These ions play important biological functions, and these include the zinc ion. Zinc plays a key role in development of bone and affects cells in the positive manner; therefore, zinc substitution into HA has been a relevant subject of research and development. This chapter highlights the importance of zinc from a biological standpoint (in the human body) and the influence of its substitution in HA (e.g., on solubility, crystallinity, and thermal properties). Different methods for synthesis of zinc-substituted HA (Zn-HA) as well as different techniques used for its characterization have also been introduced. These include electron microscopy, surface area analysis, X-ray diffraction, Fourier-transform infrared and Raman spectroscopy, and thermogravimetric analysis. Key in vitro and in vivo studies undertaken for assessment of Zn-HA from a biological standpoint have also been discussed.