Calcium Phosphates for Bone Tissue Regeneration—Influence of Synthesis Method on Physicochemical and Biological Properties

Calcium phosphates, including hydroxyapatite, are widely used biomaterials in bone tissue regeneration due to their bioactivity, osteoconductivity, and similarity to the mineral phase of bone. In this study, various apatite calcium phosphate powders were synthesized using three precipitation methods, with controlled pH conditions and reagent ratios, to assess the effect of the synthesis method on their physicochemical and biological properties. Elemental composition (Ca/P ratio), FT-IR spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with EDS, and particle size measurements were used to determine the structure, morphology, and stoichiometry of the obtained powders. The results indicated that the synthesis method and pH significantly affect the phase composition of the material, particle size, and Ca/P ratio, which directly influence their solubility and bioactivity. Microbiological tests, NF-κB transcription factor activation, metabolic activity, and cell compatibility of mouse L929 fibroblasts and human hFOB 1.19 osteoblasts showed good biological tolerance of the obtained powders and no cytotoxic effects. The results confirm that a properly selected synthesis method allows for the control of material properties, which is crucial for applications in bone tissue engineering. The materials show potential for use as bioactive components in bone-related biomaterials.