Comparative Study of the Effects of Strontium and Magnesium Ions on Physical and Chemical Properties of Calcium Phosphate-Gelatin Biomimetic Scaffolds in Bone Tissue Engineering

In this study, biomimetic scaffolds were designed to study the formation of calcium phosphate deposits by using a double diffusion method into gelatin hydrogel in temperature and pH similar to body conditions. Moreover, the effect of magnesium (Mg) and strontium (Sr) ions on properties was investigated. Five different types of specimens with different Sr and Mg ions percentage were synthesized and then porous scaffolds were prepared by freeze-drying method. The scaffolds microstructures were examined by scanning electron microscopy (SEM), which showed a smooth and needle-shaped surface of specimens. Fourier transform infrared spectroscopy (FTIR) results indicated the presence of phosphate and hydroxyl bonds in the structure of the scaffolds, due to the formation of calcium phosphate phases such as HA. The presence of metal ions in the structure caused the displacement of the peaks in X-ray diffraction (XRD) analysis and lattice parameters. Additionally, osteoblast cell culture results also demonstrated M10 and S10 specimens had proper biocompatibility. Additionally, alkaline phosphate (ALP) activity revealed the optimal amount of 10 mol. % Mg and Sr (M10 and S10), which led to the significantly (**p< 0.01, ***p <0.001) growth, proliferation, and differentiation of 292G osteoblasts cells in scaffolds. Moreover, the presence of calcium phosphate improved the biological properties of the specimens. Finally, the results of various analyses confirmed the high capability of the synthesized scaffold as a promising substitute for bone tissue.