Precipitation of biomimetic fluorhydroxyapatite/polyacrylic acid nanostructures

• Biomimetic fluorhydroxyapatite/polyacrylic acid nanostructures were prepared by a wet precipitation route.
• The nanostructures are composed of ordered bundles of nanorods similar to natural tooth enamel.
• The formation of these nanostructures was explained by examining the interactions between COO− of PAA and Ca2+ of FHA.

Ordered structures of fluorhydroxyapatite (FHA) nanoparticles that resemble the nanostructure of natural human enamel have been prepared. Wet precipitation in the presence of polyacrylic acid (PAA) was used, and the particle morphology was altered by varying several reaction conditions. High molecular weight PAA increased particle length from around 54 nm to several hundred nanometres, while maintaining particle width at 15 nm. PAA concentration and the order of mixing the reactants also influenced crystal morphology. Optimum conditions produced dense, aligned bundles of highly elongated nanorods, which are very similar to the hierarchical nanostructure of human tooth enamel.