2.4.1. Biominerilization Studies

To evaluate the apatite-forming ability (bioactivity), the substrates were immersed in 30 mL of simulated body fluid (SBF) with material composition and composition nearly equal to human blood plasma for 14 days. The SBF solution is prepared in the laboratory by mixing laboratory-grade chemicals (NaCl, NaHCO3, KCl, K2HPO4·3H2O, MgCl2·6H2O, CaCl2, and Na2SO4) in deionized water and maintained at pH 7.4 with tris (hydroxy-methyl) aminomethane and 1 M HCl. The detailed information on ion concentrations of SBF proposed by Kokubo et al. without organic species and its correlation with human blood plasma can be found elsewhere [35]. The falcon tubes containing SBF and substrates were immersed in water bath, maintained at static conditions at 37 ◦C. After immersing for 14 days, the substrates were carefully taken out from the SBF solution, washed with deionized water and freeze dried at room temperature for further morphological and elemental analysis.
