Abstract:
In order to maximize the bioactivity of prosthetic materials, synthesis of
nanosized hydroxyapatite is required. In addition, it is highly desirable the
synthetic hydroxyapatite to have similar chemical substitutions and morphology
of biological apatites. A novel method has been developed to produce single
phase, nano sized, plate-like, mixed A-B type carbonate containing apatite
(CAp) similar to bone apatite for effective bone tissue integration. The
methodology emulates biomineralization, where topotactic transition from
octacalcium phosphate (OCP) to hydroxyapatite (HAp), which is believed to
occur in vivo. The process involves formation of thin (-1.4 nm) layered calcium
phosphonate salts by a self-assembly process. The thermal decomposition of
these layered salts leads to formation of plate-like carbonated apatite. The
overall carbonate content varies from 6.4 to 4 wtOk), within the temperature range
of 500 - 700 DC. This carbonate content corresponds well with the amount found
in mammalian hard tissues.
