2.3. Soaking in SBF
In order to estimate the bioactivity of the ceramics, Kokubo et al.37 proposed in 2006 the Tris-buffered SBF, with an ion concentration nearly equal to that of human blood plasma. The ceramic disks were placed in polystyrene bottles containing 50 ml of SBF at pH = 7.40. The solid/liquid weight ratio was equal to 5 × 10−3. The bottles with SBF and samples were incubated at 37 ± 0.5 °C in a shaking water bath for predetermined intervals. After different soaking periods (up to 14 days) the disks were removed from SBF, rinsed with deionized water, and dried at room temperature.