Synthesis and characterization of tricalcium phosphate with Zn and Mg based dopants

The purpose of this study is to prepare tricalcium phosphate (TCP) ceramic by dual dopants of magnesium (Mg) and zinc (Zn), and investigate the influence of dopants on the physical, mechanical and biological properties of TCP. TCP were synthesized with 1 wt% Mg, 0.3 wt% Zn and dual dopants using the precipitation process. Phase composition and microstructures were characterized. Mechanical properties and dissolution behavior in vitro were investigated. Human osteoblast cell culture was used to determine the influence of dopants on cell-materials interactions. XRD analysis indicated that Mg delayed phase transformation from beta to alpha-TCP and pure beta-TCP phase was obtained for Mg-doped TCP after sintered at 1250 degrees C. Addition of Mg improved densification behavior of TCP. Compression strength also increased from 24.0 MPa to 77.2 MPa after doping with Mg and Zn. Furthermore, Mg additive reduced the solubility of TCP in vitro. Osteoblast culture studies indicated that the presence of Mg stabilized the cell-material interface and thus improved cell attachment and growth. Zn-doped TCP exhibited good bioactivity, which enhanced cell differentiation and alkaline phosphatase (ALP) expression. The highest cell proliferation and ALP expression were found on dual Mg and Zn doped TCP. The results indicate that Mg and Zn dopants play a significant role towards improving mechanical properties and cell-materials interactions of TCP. This work also demonstrates the potential for dual Mg and Zn doped TCP to be used in orthopedics and dentistry, which displays high mechanical strength, low resorption and improved cell-material interaction.