Template directed synthesis of nanosized bone-like apatite

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.