Understanding the influence of MgO and SrO binary doping on the mechanical and biological properties of β-TCP ceramics

The objective of this study was to evaluate the influence of MgO and SrO doping on the mechanical and biological properties of β-tricalcium phosphate (β-TCP). β-TCP was doped with two different binary compositions, 0.25 and 1.0 wt.% SrO along with 1.0 wt.% MgO. MgO and SrO doping increased the β phase stability at a sintering temperature of 1250 °C and marginally decreased the compressive strength of β-TCP. An in vitro cell–material interaction study, using human fetal osteoblast cells (hFOB), indicated that doped β-TCP was non-toxic, and MgO/SrO dopants improved cell attachment and growth. β-TCP implants doped with 1.0 wt.% MgO and 1.0 wt.% SrO showed good in vivo biocompatibility when tested in male Sprague–Dawley rats for 16 weeks. Histomorphology analysis indicated that MgO/SrO-doped β-TCP promoted more osteogenesis than pure β-TCP. In vivo osteocalcin and type I collagen assay also revealed faster bone formation in rats with doped β-TCP implant compared to rats with pure β-TCP implant. Low Ca2+ concentration in the urine of rats with doped β-TCP implant confirmed slower degradation of MgO/SrO-doped β-TCP than pure β-TCP.