Strontium Substituted β-Tricalcium Phosphate Ceramics: Physiochemical Properties and Cytocompatibility

Bone graft materials must support cell activity and degrade safely. Traditional ceramics like β-tricalcium phosphate (β-TCP) are widely used but lack long-term osteogenic support. Researchers have explored modifying β-TCP with strontium to enhance its biological performance. However, the physiochemical and biological effects of strontium substitution remain unclear. Prior studies have shown that strontium can influence bone formation and resorption. Yet, the impact of varying strontium concentrations on ceramic phase stability and cell interactions is not fully understood. This gap motivated the current investigation into strontium-substituted β-TCP ceramics. The study aimed to assess how strontium affects phase composition, microstructure, and cell behavior. No prior work had resolved the relationship between strontium content and in vitro cytocompatibility. Understanding these factors is essential for developing advanced bone graft materials.

This research aimed to evaluate the physiochemical and biological properties of strontium-substituted β-tricalcium phosphate ceramics. The goal was to determine how strontium content influences phase stability, microstructure, and cell compatibility. The researchers focused on two strontium concentrations: 3.33 mol.% and 16.67 mol.%. The study used human osteosarcoma MG-63 cells to assess viability and adhesion. The motivation was to improve the performance of β-TCP in bone regeneration applications. The team wanted to understand the relationship between strontium substitution and ceramic degradation. They also sought to measure strontium ion release over time. This work provides a foundation for future in vivo testing of these materials.

The researchers used mechano-chemical activation to synthesize strontium-substituted β-TCP powders. The samples were pressed and sintered to form ceramic specimens. Three compositions were tested: 0 mol.%, 3.33 mol.%, and 16.67 mol.% strontium. Energy-dispersive X-ray spectrometry confirmed the chemical composition of the samples. Inductively coupled plasma optical emission spectroscopy measured strontium content. Powder X-ray diffraction analyzed the phase composition of the ceramics. The ceramics were soaked in saline solution for 21 days to simulate in vivo conditions. Phase changes and microstructural evolution were monitored during this period. Strontium ion release was quantified using ICP-OES. Cell-based assays evaluated MG-63 cell viability and adhesion on the ceramic surfaces.

The phase composition analysis showed β-TCP as the main phase in non-substituted and 0.5SrTCP samples. The 0.1SrTCP sample exhibited a dominant apatite-type phase. Soaking in saline led to partial dissolution of β-TCP and formation of apatite in TCP and 0.5SrTCP. Microstructural changes were observed in all samples after 21 days. Strontium ion release was measured using ICP-OES, with values increasing over time. The 0.5SrTCP sample released the highest amount of strontium ions. MG-63 cell viability was significantly higher on strontium-substituted samples. Cell adhesion and spreading improved with increasing strontium content. The 0.5SrTCP sample showed the best cytocompatibility. These findings suggest that strontium substitution enhances the biological performance of β-TCP.

The study demonstrated that strontium substitution alters the phase composition and microstructure of β-TCP ceramics. The 0.5SrTCP sample showed the most favorable changes in phase and ion release. The presence of strontium improved cell viability and adhesion on the ceramic surfaces. The researchers propose that strontium enhances the biological compatibility of β-TCP. The findings suggest that strontium-substituted ceramics may be suitable for bone graft applications. The observed apatite formation supports the potential for in vivo integration. The study provides a basis for further in vivo experiments with these materials. The authors suggest that the results may inform the design of next-generation bone grafts.