Resorbable Tricalcium Phosphates for Bone Tissue Engineering: Influence of SrO Doping

Tricalcium Phosphate (TCP) was doped with 0.5, 2.0, and 5.0 mol% Strontium Oxide (SrO) through the wet precipitation process to investigate the influence of SrO on the biological and mechanical properties of TCP. XRD results showed that SrO doping did not change the phase stability of the beta-phase of TCP during sintering at 1120 degrees C. The apparent density of TCP increased from 95.1 +/- 2.5% to 99.4 +/- 0.5% with the addition of 5.0 mol% SrO doping. SrO doping also increased the compressive strength of pure beta-TCP from 121.1 +/- 21.4 MPa to 185.9 +/- 16.7 MPa with 5 mol% SrO addition. Initially, the addition of 0.5 and 2.0 mol% SrO had a statistically insignificant impact on the as-processed samples' compressive strength. When the samples were immersed in a simulated body fluid for 12 weeks, the addition of SrO improved the compressive strength from 109.4 +/- 22.9 MPa for pure TCP to 208.8 +/- 34.6 MPa with 5.0 mol% SrO addition. An improvement in hFOB cell attachment and proliferation was observed for all dopant concentrations using field emission scanning electron microscope (FE-SEM) imaging and MTT assay studies, indicating excellent biocompatibility of all the samples. 2.0 mol% SrO doping showed the best cell differentiation and proliferation results. It was shown that SrO simultaneously improved mechanical properties of TCP such as compressive strength as well as biological properties via enhanced cell attachment and proliferation.