Fabrication and Characterization of Sr-doped Hydroxyapatite Porous Scaffold

Strontium (Sr) is a trace metal ion that exists in natural bones. It not only regulates metabolism but also promotes osteoblast differentiation and the formation of new bones. In this study, a new method was developed to prepare Sr-doped hydroxyapatite (HA) three-dimensional (3D) porous scaffolds. A preliminary scaffold was obtained by an extrusion 3D printing method using HA–sodium alginate composite slurry as printing ink. Then, the obtained scaffolds were immersed in a strontium chloride (SrCl 2 ·6H 2 O) solution of different concentrations (1 wt.%, 5 wt.%, 10 wt.%, and 15 wt.%) for 24 h. Finally, the scaffolds were dried and then sintered at 1200°C to obtain the final scaffolds. The Sr-doped scaffolds were characterized by scanning electron microscopy, x-ray diffraction, Fourier-transform infrared spectroscopy, mechanical testing, and cell culture testing. The results show that the Sr-doped HA scaffold has better compactness and compressive strength than the HA-0Sr scaffold, and promotes cell proliferation and osteoblast differentiation. This indicates that the alternative method is suitable for preparing ion-doping ceramic scaffolds for bone tissue engineering.