Effects of Si/Zn Co‐Substitution on the Physicochemical Properties, In Vitro Angiogenic Potential, and Osteogenic Activity of β‐Tricalcium Phosphate

Abstract

Zinc ions have shown promising osteogenic activity, while silicon ions promote angiogenesis. In this study, the effects of silicon doping, zinc doping, and their co‐doping on the physicochemical properties, as well as the in vitro angiogenic and osteogenic activities of β‐tricalcium phosphate (β‐TCP), are investigated. In the findings, it is revealed that silicon doping primarily occurs on the P1 site, leading to lattice stability disruption in β‐TCP and favoring its transformation into α‐TCP (α‐TCP). Notably, a significant portion of silicon ions is distributed on the particle surface. As a result, silicon‐doped TCP (Si–TCP) exhibits remarkable in vitro mineralization activity. Conversely, zinc doping contributes to stabilizing the β‐TCP phase, even at a sintering temperature of 1200 °C, preventing the formation of α‐TCP. Silicon/zinc‐co‐doped TCP (Si/Zn–TCP) displays comparable physicochemical properties to zinc‐doped TCP (Zn–TCP), thus demonstrating higher thermal stability than pure β‐TCP. Cell response evaluations indicate excellent biocompatibility for Si–TCP, Zn–TCP, and Si/Zn–TCP. Silicon doping significantly enhances in vitro angiogenic capability, while zinc doping notably improves osteogenic potential of β‐TCP. Furthermore, the bifunctional ion‐co‐doping approach in Si/Zn–TCP results in combined angiogenic promoting from Si–TCP and osteogenic stimulation from Zn–TCP. In these results, the considerable potential of Si/Zn–TCP is highlighted for bone defect repair applications.