纳米羟基磷灰石/硫酸钙人工骨在模拟体液浸泡环境下的行为研究

Behavior of a Nano-sized Hydroxyapatite and Calcium Sulphate Bone Substitute Composite Soaked in Simulated Body Fluid

目的将纳米羟基磷灰石与半水硫酸钙组合构建一种可注射的人工骨材料,研究其在模拟体液环境中的降解与物质变化,并探讨该变化与材料成骨活性的关系。方法采用模拟人体体液SBF9#浸泡两种晶体物质和不同成分组合的复合材料样品,测定失重率、钙磷元素释放速率,并对材料表面形态和晶体变化作扫描电镜观察和XRD分析。结果纯羟基磷灰石在早期快速失重后保持稳定,其余材料均稳定降解,复合材料的HA含量越高,降解速率越快。纳米羟基磷灰石组的溶液Ca浓度始终较低;各组均有P元素释出,但随时间减少。XRD分析发现复合材料浸泡中CS峰下降,HA峰强度增高。扫描电镜观察到浸泡后复合材料表面呈现新的晶体形态。结论CSD与HA在SBF环境下可能出现表面Ca、P的释放-吸附动态过程,材料的降解速度主要取决于CSD,可通过调节成分配比而加以控制。

Objective To evaluate the degradative and structual characteristics of a new injectable nano- hydroxyapatite/calcium sulphate bone substitute under simulated body fluid environment, and to study it＇s correlation to bone-inducing activity. Methods Sample 1 to 5 （CSD, n-HA and CSD ＋ 10% HA, CSD ＋ 20% HA, CSD ＋ 40%HA, respectively） were soaked into SBF9# solutions. Daily losing mass of all samples, Calcium and Phosphorus element concentration of solutions were measured. Scaning electron microscope observation and XRD analysis were also performed. Results Sample of n-HA underwent a rapid weight losing within the first 24h after soaking and then kept stable. The higher content of HA, the more rapid weight losing of composite material was observed in Samplel and 3-5. A sustaining lower Ca^2＋ concentration was observed in solutions for Sample 2. Phosphorus content was released from all samples and decreased when soaking time was increased. XRD indicated that the diffractive waves of HA enhanced in sample 3-5, while SEM showed HA gathering-like formation on the composite surfaces. Conclusion A Interactions between CSD and n-HA may exist in composite and result in a dynamic equilibrium of Ca/P releasing-adsorpsion occurring on material surface, lead to a new apatite layer formed. The degradation rate of composite may correlate with CSD content and would be adjusted by regulating its proportion.