Improvement of in vitro degradation of magnesium oxychloride cement for bone repair by chitosan

Ideal inorganic bone cement used for bone repair should have high strength, and the speed of degradation should match the formation rate of new bone tissue. Magnesium oxychloride cement has excellent mechanical properties and non-toxicity to bone marrow stromal cells; however, its application has been hindered by its poor water resistance. In this study, the high-degradation material chitosan (CS) was added to magnesium oxychloride cement (MOC). The compressive strength, mass loss, ion release, and pH value of the composite MOC were analyzed and scanning electron microscopy, energy dispersive spectroscopy, X-ray diffraction, and Fourier transform infrared spectroscopy were conducted. The compressive strength was 45.4 ± 5.3 MPa in cements with 0.5-wt% CS and 2-wt% KH₂PO₄ soaked in SBF for 28 d, and the degradation rate reached 12.67 ± 0.5%. SEM observations showed good apatite formation of the surfaces of the MOC with 2-wt% KH₂PO₄ and with 0.5-wt% CS and 2-wt% KH₂PO₄. The results indicate that the modified MOC possesses good mechanical properties, degradation rate and biological properties. Therefore, it is a promising material for degradable bone filling.