Study on strontium doped tricalcium silicate synthesized through sol-gel process

Abstract

We successfully synthesized a strontium-doped tricalcium silicate (Sr_xCa_3-xSiO₅, Sr = 0 to 2 mol%) bone cement using the sol-gel process. The material properties including crystallinity, setting time, mechanical strength, and hydration products were characterized. Release of ions and pH values of simulated body fluid soaked with the bone cement were measured. In vitro biocompatibility of different concentrations of the material was evaluated by the viability of L929 cells. The setting times of as-prepared slurries were all <70 min. Doping with 0.5 mol% Sr reduced the final setting time by 20 min. After 14 days curing, 0.25 mol% Sr-doped Sr_xCa_3-xSiO₅ possessed the highest compressive strength of 45 MPa among all the Sr-doped groups with no statistical difference to Ca₃SiO₅. The bioactivity of the materials was confirmed with the formation of an apatite layer on the surface of the materials after immersion in simulated body fluid. In addition, the proliferation of L929 cells exposed to 1 mol% Sr was significantly promoted as compared to no Sr doping. Sr_xCa_3-xSiO₅ is a novel and advanced material that has the potential to serve as a bone cement in bone restoration with appropriate mechanical strength and favorable biocompatibility.

Keywords: Biocompatibility; Bone cement; Sol-gel process; Strontium; Tricalcium silicate.