Formation of biomimetic apatite on calcium phosphate foam ceramics in the concentrated model solution

By firing polyurethane foam templates (“STR” brand, 12 pores per cm, China) with a porosity of ~ 65 % at 1200 °С, an open-pore calcium phosphate foam ceramics was obtained using a highly concentrated suspension based on synthetic hydroxyapatite, heat-treated at 800 °С, monocalcium phosphate monohydrate and 0.8 % polyvinyl alcohol. The resulting calcium phosphate foam ceramics after modification in the SBF (Simulated Body Fluid) solution concentrated 5 times (SBF×5) consisted of β-tricalcium phosphate, β-calcium pyrophosphate and biomimetic apatite, had a porosity of 53 – 59 % and a static strength of ~ 0.05 MPa. The formed biomimetic apatite, consisting of amorphous calcium phosphate Ca9(PO4)6 and apatite tricalcium phosphate Ca9HPO4(PO4)5OH, crystallizes into β-tricalcium phosphate at 1200 °С. Calcium phosphate foam ceramics modified with biomimetic apatite, after soaking in 5 % hydroxyapatite gel and SBF×5, which simulating a bone defect in vitro, in parallel with the formation of biomimetic apatite, is partially destroyed, which confirmed its high bioactivity and degradation.