Tannic acid-modified magnesium oxychloride bone cement with high water resistance and osteogenic properties

Magnesium oxychloride bone cement (MOC) is a bone replacement material that exhibits excellent mechanical properties and is non-toxic. However, the material exhibits poor water resistance, as the 5-phase composition of MOC decomposes readily in the presence of water. Tannic acid (TA) is an organic acid with favorable biocompatibility, containing a large amount of-OH that can form chelates with metal ions. Therefore, we plan to control spill Mg2+ in MOC using TA to improve its water resistance. The results demonstrate that the addition of TA resulted in a denser structure of MOC, an improved stability of the 5-phase in solution, a reduced degradation rate and pH value of MOC in body fluids, and the generation of hydroxyapatite in vitro. Furthermore, the MOC modified with TA demonstrated enhanced cell proliferation and increased new bone formation in cellular and animal experiments. This high-strength, highly bioactive material system is adaptable to patient-specific requirements and has significant potential for clinical translation.