Strontium substituted biomimetic calcium phosphate system derived from cuttlefish bone

Biomimetic triphasic strontium-substituted calcium phosphate (CaP) powders were prepared by wet precipitation method at 50 degrees C, using CaCO3 , (NH2 )2 COH3 PO4 , and Sr(NO3 )2 as reagents. Calcite was prepared from biogenic source (cuttlefish bone). The synthesized powders have been characterized by elemental analysis, Fourier transform infrared spectrometry, X-ray diffraction, Rietveld refinement studies and cell viability test. Phase transformation and ion release were analyzed during 7 days of incubation in simulated body fluid at 37 degrees C. The raw precipitated powders were composed of calcium deficient carbonated hydroxyapatite (HA), octacalcium phosphate (OCP), and amorphous calcium phosphate (ACP). After heat treatment at 1200 degrees C beta-tricalcium phosphate (beta-TCP) was detected. Strontium substitution for calcium results in an increase of lattice parameters in HA, OCP, and beta-TCP. Sr(2+) occupy the Ca(1) site in HA, Ca(3,4,7,8) sites in OCP and Ca(1,2,3,4) sites in beta-TCP. Along with Sr(2+) substitution, presence of Mg(2+) and Na(+) ions was detected as a result of using biogenic calcium carbonate. The culture of human embryonic kidney cells indicated noncytotoxicity of the prepared CaP powders with emphasis on the cell proliferation during 3 days of culture.