Objective: To extend its application in the field of bone repair by adding oxygen-carboxymethylated chitosan (O-CMC) and gentamicin for modification of the calcium sulfate cement (CSC).
Methods: The O-CMC/CSC was prepared by adding O-CMC with different concentrations (0.1wt%, 0.3wt%, 0.5wt%, 0.7wt%, and 1.0wt%) in the CSC liquid phase. The effect of O-CMC on the CSC was evaluated by testing the injectability, compressive strength, degradation rate, pH value, cytotoxicity and osteogenesis. After the optimal concentration of O-CMC was determined, gentamicin with different concentrations (0.5wt%, 1.5wt%, and 2.5wt%) was added in the O-CMC/CSC, and then the compressive strength and antibacterial properties were investigated.
Results: After adding O-CMC in the CSC liquid phase, the injection time of O-CMC/CSC was increased to more than 5 minutes; it significantly prolonged with increased concentration of O-CMC ( P<0.05). The compressive strength of the modified bone cement was in the range of 11-18 MPa and it was the highest when the concentration of O-CMC was 0.5wt% ( P<0.05). The degradation rate of O-CMC/CSC was not influenced obviously by O-CMC ( P>0.05). The pH value was in the range of 7.2-7.4 and Ca 2+ concentration was in the range of 6-8 mmol/L. In vitro mineralization experiment indicated that the induced mineralization ability of O-CMC/CSC was much higher than that of pure CSC. The 0.5wt% O-CMC/CSC had the best performance; the compressive strength of the composite bone cement was above 5 MPa after gentamicin was added, which had antibacterial effect.
Conclusion: O-CMC is able to effectively improve the injection, compressive strength, and osteogenic activity of CSC; in addition, antibacterial properties is obtained in the CSC after adding gentamicin.
目的: 通过添加 O-羧甲基壳聚糖（oxygen-carboxymethylated chitosan，O-CMC）和庆大霉素对硫酸钙骨水泥（calcium sulfate cement，CSC）进行改性，提高其在骨修复领域应用的可行性。.
方法: 通过在 CSC 液相中添加不同浓度 O-CMC（0.1wt%、0.3wt%、0.5wt%、0.7wt%、1.0wt%），制备 O-CMC/CSC。通过可注射性、抗压强度、降解率、模拟体液 pH 值及Ca 2+ 浓度测试、成分与形貌表征观察以及细胞毒性测试，分析 O-CMC 浓度对 CSC 在可注射性、抗压强度、降解行为及成骨活性方面的影响。综合以上检测指标，确定最佳性能的 O-CMC/CSC，并以此复合不同浓度庆大霉素（0.5wt%、1.5wt%、2.5wt%），探究其抗压强度和抗菌性。.
结果: O-CMC/CSC 可注射时间均超过 5 min，且随 O-CMC 浓度的增加而显著延长（ P<0.05）。改良后的骨水泥抗压强度介于 11～18 MPa 之间，0.5wt%O-CMC/CSC 抗压强度最高（ P<0.05）。O-CMC/CSC 降解速率随 O-CMC 浓度增加而呈减小趋势，但组间比较差异无统计学意义（ P>0.05）。浸泡液 pH 值变化在 7.2～7.4 之间，Ca 2+ 浓度稳定在 6～8 mmol/L。成分与形貌表征观察显示，相比于 CSC，O-CMC/CSC 在模拟体液中的诱导矿化能力更强，具有更好生物活性。综合以上检测指标结果，确定 0.5wt%O-CMC/CSC 性能最佳，加入庆大霉素后其抗压强度均大于 5 MPa 且具有抗菌性。.
结论: O-CMC 能够有效提高 CSC 的可注射性、抗压强度和成骨活性，加入庆大霉素后复合骨水泥具有抗菌性。.
Keywords: Calcium sulfate cement; antibacterial property; gentamicin; oxygen-carboxymethylated chitosan.