Hydroxyapatite (HAp), one of the calcium phosphate minerals, has been
widely used for biomedical applications because of its similarity to bone mineral
content. Synthetic nano HAp, despite being made from chemical precursors, differs in
composition from that of natural hard tissues such as bone and teeth. The properties of
synthetic HAp solely depend on the precursors and production processes employed.
Biogenic calcium resources such as fish scales, bones of animals and fish, and shells
from land, freshwater, and marine origin can be used to synthesise HAp, which has
trace elements that mimic the constituents of bone. Also, we have emphasised that HAp
can be synthesised economically from one of the abundantly available low-cost
biowastes, namely eggshells. There are numerous biomedical uses like bone substitute
material, scaffold for bone tissue engineering, drug delivery agent, etc., and
environmental uses, notably as an adsorbent for heavy metal removal, dye degradation,
etc. This chapter will help readers understand the significance of natural resources and
methods for producing HAp from biogenic sources.
Keywords: Biomedical applications, Calcination, Calcium phosphates, Hydroxyapatite.
