丝素蛋白对磷酸钙骨水泥抗压强度及注射性的影响术

背景:高分子材料对磷酸钙骨水泥力学性能的增强作用已得到了一定的证实,但往往会同时减弱复合材料的注射性能,影响复合材料的临床应用.目的:将丝素蛋白加入磷酸钙骨水泥固相粉末中,观察其对骨水泥抗压强度和注射性的影响.设计、时间及地点:对照实验,于2007-09/12在苏州大学分析测试中心实验室完成.材料:磷酸钙骨水泥购自上海瑞邦生物材料有限公司,丝素蛋白为苏州大学材料工程学院自行合成.方法:按5,10,15,20,25,30 g/L的丝素蛋白质量比例,用自制的粉末搅拌器将丝素蛋白粉末和骨水泥固相粉末混合均匀,依次设为6个实验组,以单纯磷酸钙骨水泥为对照组,液固比均为0.4 mL/g.主要观察指标:测定丝素蛋白/磷酸钙骨水泥复合材料的抗压强度、注射系数,应用扫描电镜观察试件断裂面的微脱结构特征.结果:随着丝素蛋白质量比例增加,磷酸钙骨水泥的抗压强度呈现先上升后下降的趋势,当丝素蛋白质量比例为1%-2.5%时,抗压强度显著高于对照组(P<0.05).注射系数随着丝素蛋白质量比例增加而逐渐下降,当丝素蛋白质量比例为1.5%-3%时,注射系数显著低于对照组(P<0.05).扫描电镜发现,丝素蛋白呈网状,贯穿于磷酸钙水泥晶体间,并将磷酸钙水泥晶体紧密连接.结论:丝素蛋白能在不明显影响注射操作的情况下,显著提高丝素蛋白/磷酸钙骨水泥复合材料的抗压强度.

Influences of silk fibroin on the compressive strength and injectability of calcium phosphate cement

BACKGROUND: High molecular materials have been proved to enhance the mechanical properties of calcium phosphate bone cement, as well as attenuate the injectability of composite materials. It thereby influences the clinical application of composite materials.OBJECTIVE: To observe the compressive strength and injectability of silk fihroin compound calcium phosphate bone cement, to evaluate the effect of silk fibroin on calcium phosphate, and to investigate the feasibility of applying silk fibroin as an injectable hone substitute to repair hone defects.DESIGN, TIME AND SETTING: Controlled study was performed in the central laboratory of Analysis and Testing Center, Soochow University from September to December in 2007.MATERIALS: Calcium phosphate cement was purchased from Shanghai Rebone Biomaterials Co., Ltd; silk fibroin was offered by Institute of Material & Engineering, Soochow University.METHODS: Six groups were set with different mass fractions (0.5%, 1%, 1.5%, 2%, 2.5%, 3%) of silk fibroin, which were mixed with bone cement at a certain liquid/solid ratio of 0.4 mL/g to prepare the calcium phosphate composite. The calcium phosphate cement without silk fibroin was served as control group.MAIN OUTCOME MEASURES: The compressive strength and injectability were determined. The characteristic microstructure was observed using scanning electron microscope.RESULTS: The compressive strength increased firstly and then decreased with the addition of silk fibroin. The compressive strength of the experimental groups was remarkably higher than the control group when the silk fibroin content was 1%-2.5% (P<0.05). The injectability of the paste diminished with the addition of silk fibroin, which was statistically different when the silk fibroin content was 1.5%-3% (P<0.05). Scanning electron microscope result revealed that the silk fihroin penetrated throughout calcium phosphate crystals, which were tightly connected.CONCLUSION: Silk fibroin can improve the compressive strength of silk fibroin/calcium phosphate cement composites without significant influence of manipulation, and can widen the application field of calcium phosphate bone substitute.