Synthesis and characterization of Mg and Sr-modified calcium phosphate/gelatin biomimetic scaffolds for bone tissue engineering

In this study, biomimetic scaffolds were designed and synthesized by the double diffusion method to study the formation of calcium phosphate deposits into gelatin hydrogel in similar body temperature and pH conditions. Moreover, the effect of the presence of magnesium (Mg) and strontium (Sr) ions as modifiers was evaluated on their properties. Five types of specimens were synthesized by changing the Mg and Sr ions ratio and were shaped into porous scaffolds by the freeze-drying method. Scanning electron microscopy (SEM) examined the scaffolds' microstructure, which showed a smooth and needle-shaped surface. The results of Fourier transform infrared spectroscopy (FTIR) indicated the presence of phosphate and hydroxyl bonds in the structure of the scaffolds, which could be due to the formation of calcium phosphate (CP) phases such as hydroxyapatite (HA). The presence of metal ions in the structure caused the formation of HA after 3 days in the simulated body fluid (SBF). The results of bone cell culture also demonstrated significant biocompatibility of specimens containing 5 mol.% Sr and Mg with G292 osteoblasts. Additionally, the result obtained from alkaline phosphate (ALP) activity showed that the specimens contained 5 mol. % Mg and Sr had significant ALP activity compared to other specimens. These fabricated scaffolds revealed better biological and structural properties. Finally, the results confirmed the high capability of the fabricated scaffold as a suitable substitute for bone tissue.