柠檬酸添加壳聚糖及明胶固化液与α-磷酸三钙和羟基磷灰石复合制备骨水泥的黏度及形状特点

Viscosity and shape of bone cement prepared by chitosan, gelatin and citric acid for hardening liquid with alpha-tricalcium phosphate and hydroxyapatite powder

目的:利用在柠檬酸中添加壳聚糖、明胶配制的固化液与α-磷酸三钙和羟基磷灰石复合的粉剂调和制备骨水泥试样,观察其黏度和形状。方法:实验于2005-03/2006-08在兰州交通大学材料系实验室完成。①实验方法:骨水泥固相粉末是α-磷酸三钙和羟基磷灰石混合均匀制得的骨水泥粉料,液相部分是将壳聚糖和明胶按体积分数为0.03,0.06,0.09,0.12,0.15与柠檬酸溶液混合配制的固化液,将二者调和制得骨水泥。②实验评估:采用X射线衍射仪测试试样晶型及组成;测定骨水泥凝固时间;通过MTS-810型材料试验机测试骨水泥压缩强度;扫描电镜观察固化体微观结构;将骨水泥样本置于37℃生理盐水中,并在1,3,5,7,9,12,24h测试生理盐水的pH值。结果:①骨水泥组成:X射线衍射仪显示粉剂中仅存在两个晶相:羟基磷灰石/高温型磷酸三钙。②骨水泥凝固时间:调和液的黏度明显增加,试样调拌时像口香糖一样黏性很大,固化时间延长,抗水冲性能提高,样品塑型容易操作。在(2.0±0.2)min时出现初凝,骨水泥的黏性逐渐减退,在(8.0±0.2)min时骨水泥完全固化,骨水泥固化时间有所延长。③骨水泥压缩强度:固化液中壳聚糖-明胶体积分数为0.09时压缩强度较高(26.0±3.2)MPa;骨水泥于浸泡6h的强度已达其最大强度的85%以上,24h基本达到最大强度,在48h后强度几乎不再变化。④固化体微观结构:完全固化后,形成棒状结晶和花朵状的结晶,晶体很小,在低倍镜下观察,似无定形物质。固化后形成的磷酸钙结晶在形态学上与自然骨非常相似。⑤生理盐水的pH值:pH值随着水化反应的进行逐渐上升,浸泡12h时上升为6.89±0.02,浸泡24h时pH值达到7.02±0.02,接近生理盐水的pH值。结论:制备的骨水泥克服了陶瓷型羟基磷灰石烧结形成、修整困难等缺点,具有塑型容易、使用方便、固化时放热小等优点,可应用于体内骨修复材料。

AIM： Using citric acid, chitosan and gelatin to produce hardening liquid, and mixing alpha-tricalcium phosphate （α-TCP） with hydroxyapatite （HAP） to produce a powder, bone cement sample is obtained after mixing the powder and liquid components together, its viscosity and shape are also observed. METHODS： Expenments were completed in the laboratory of Materials Department of Lanzhou Jiaotong University from March 2005 to August 2006.①Experiment method： The powder component of bone cement was consisted of α-TCP and HAP, which was homogenized. The liquid component included citric acid, chitosan and glucose solution, which was mixed according to a certain proportion （0.03, 0.06, 0.09, 0.12, 0.15）. Then the bone cement was produced by mixing the power and liquid components. ②Expedmental evaluation： X-ray diffractometer was used to test the sample crystal and composition. Solidification time of bone cement was measured. Compressive strength of bone cement was tested using MTS-810 material testing machine. Microstructura of hardened sample was observed with scanning electron microscope. The samples were immersed in the physiological saline at 37 %, and the pH value was determined 1, 3, 5, 7, 9, 12, 24 hours later. RESULTS： ①Bone cement composition： X-ray diffraction showed that the powder only existed two phases： HAP/high temperature-TCP.②Bone cement solidification time： The consistency of the hardening liquid obviously increased. When mixing the powder and liquid components together, it showed chewing-gum-like consistency, the water-resistance of samples raised, the hardening time prolonged, so the samples could be easy molded. At （2.0±0.2） minutes the sample emerged initial setting, its viscosity gradually diminished, and the sample completely hardened at （8.0±0.2） minutes, its solidification time also prolonged. ③Bone cement compressive strength： When the content of chitosan-gelatin in the hardening liquid was 9%, its compression strength was higher （26.0±3.2） MPa. When the sample was immersed for 6 hours, the strength reached 85% of its maximum strength, basically achieved the peak 24 hours later, and almost no change was found after 48 hours.④Hardened body microstructure： The completely hardened sample formed rod-shaped or flower-shaped crystals, which were very small. It seemed amorphous materials under low power lens. In morphology, the calcium phosphate crystal of hardened body was very similar with natural bone. ⑤Physiological saline pH： The pH increased gradually with the procedure of hydration reaction. The pH values were 6.89±0.02 at 12 hours, and 7.02±0.02 at 24 hours, which was close to the pH of physiological saline. CONCLUSION： The prepared bone cement can be widely used as a new artificial bone substitute material. It is free from the drawback of ceramic HAP, including sintering and difficulties in shaping. It has the advantages of simple shaping, easy application and lower heat energy, etc.