Multi-metallic layered double hydroxides functionalized degradable bone cement: Modulation of degradation, sustained ion release, antimicrobial, and osteogenic properties

Endowing materials with multifunctionality through the bioactivity of metal ions is a highly effective strategy. However, the study of the combined effects of multiple metal ions and their controlled release remained relatively underexplored. In this study, layered double hydroxides (LDH) were used as carriers for multi-metal ions—Mg ²⁺, Fe ³⁺ (MgFe-LDH), and Cu ²⁺, Mg ²⁺, Fe ³⁺ (CuMgFe-LDH)—to control ion release for antibacterial and osteogenic applications. The incorporation of LDH into degradable bone cement actively participated in the hydration process, resulting in a denser microstructure, increased compressive strength, and moderated degradation rate. As the CuMgFe-LDH content increased, the mass loss over 56 days increased from 27.07 % (CuMgFe-LDH 0 %) to 45.07 % (CuMgFe-LDH 0.3 wt%) and 54.65 % (CuMgFe-LDH 0.5 wt%). Calcium and magnesium ions were released consistently over 56 days, while copper ions were released over 7 days. The CuMgFe-LDH-loaded bone cement inhibited 99.99 % of S. aureus growth after 18 h of co-culture. Cellular assays showed that LDH-functionalized bone cement significantly enhanced cell proliferation. Furthermore, the inclusion of copper ions promoted cell differentiation, with calcium nodule deposition increasing by 1.29-fold compared to pure bone cement, and osteogenesis-related gene expression doubling.