Enhanced Bioactivity and Mechanical Strength of Strontium-Doped Calcium Silicate Bioceramic Prepared Through Sol–Gel Combustion Synthesis

The field of material science is increasingly focused on developing advanced biomaterials for hard tissue engineering, addressing the growing prevalence of bone diseases and injuries. Calcium silicate bioceramics, known for their exceptional bioactivity, osteoconductivity, and mechanical stability, have emerged as a cornerstone in orthopedic applications. Strontium (Sr²⁺) doping has further emerged as a transformative approach for enhancing these properties. This study investigates the bioactivity and mechanical properties of strontium-doped rankinite (Ca_3-xSr_xSi₂O₇), synthesized via sol–gel combustion method. Strontium ions (Sr²⁺) were incorporated at the calcium (Ca²⁺) site in three concentrations: 1, 2, and 3 mol%. A single-phase rankinite structure was successfully achieved after calcination at 1200 °C for 6 h, as confirmed by XRD. XPS analysis further validated the effective incorporation of Sr²⁺ into the rankinite lattice. Bioactivity was evaluated by immersing rankinite pellets in stimulated body fluids (SBF) for nine days, during which the formation of hydroxyapatite was confirmed via XRD. Mechanical testing revealed that increasing Sr²⁺ concentrations enhanced compressive strength (ranging from 232 to 243 MPa) and Young’s modulus (from 2.35 to 2.88 GPa), indicating improved mechanical stability. These findings suggest that strontium-doped rankinite exhibits excellent bioactivity and mechanical strength, making it a promising candidate for load-bearing bone regeneration applications.

Graphical Abstract