A comprehensive review on electrical properties of hydroxyapatite based ceramic composites.

Hydroxyapatite (Ca10(PO4)6(OH)2, HAP1) an immensely favoured biomaterial in the medical industry, is known for its extensive applications in orthopaedics and dentistry because of its bioactivity and osteoconductivity. Apart from bearing chemical resemblance to the inorganic content of bone, HAp exhibit piezoelectric and pyroelectric properties, that assist in responding to mechanical stress similar to bones which aid in speeding up the healing process of large defects in fractured bones. In the recent past, extensive impetus was put in for a systematic investigation of the electrical properties for considering its applicability in bio-electronic devices. Many interesting properties have rolled out from the ongoing researches which have been discussed at length in the article. In reviewing the electrical properties, substantial emphasis was laid on the biological significance of such properties, which is the focal point behind such explorations. An attempt has also been made to review critical issues like addition of suitable composites to HAp for optimized response to various external stimulus. Such areas are hot spots of further research for a comprehensive understanding of the underlying physical phenomena. It is expected that the understanding the electrical properties would play a deciding role in developing HAp based biocompatible electronics, bio sensing and MEMS2..