UCL, Eastman Dental Institute, London, UK.
Acta Biomater. 2010 Jul;6(7):2695-703. doi: 10.1016/j.actbio.2010.01.012. Epub 2010 Jan 18.
The initial structure, setting and degradation processes of a poly(lactide-co-propylene glycol-co-lactide) dimethacrylate adhesive filled with 50, 60 or 70 wt.% reactive calcium phosphates (monocalcium phosphate monohydrate (MCPM)/beta-tricalcium phosphate (beta-TCP)) have been assessed using nuclear magnetic resonance, Fourier transform infrared spectroscopy, Raman, X-ray powder diffraction and gravimetric studies. Filler incorporation reduced the rapid light-activated monomer polymerization rates slightly, but not the final levels. Upon immersion in water for 24h, the set composite mass and volume increased due to water sorption. This promoted initial soluble MCPM loss from the composite surfaces, but also its reaction and monetite precipitation within the specimen bulk. After 48 h, composite gravimetric and chemical studies were consistent with surface erosion of polymer with reacted/remaining filler. The filled formulations exhibited more rapid early water sorption and subsequent surface erosion than the unfilled polymer. Calcium and phosphate release profiles and solution pH measurements confirmed early loss of surface MCPM with protons from polymer degradation products. At later times, the slower release of monetite/beta-TCP buffered composite storage solutions at approximately 5 instead of 3.2 for the unfilled polymer. Incorporation of filler increased both the early and later time material modulus. At intermediate times this effect was lost, presumably as a result of enhanced water sorption. The early modulus values obtained fell within the range reported for cancellous bone. Despite surface degradation, initial human mesenchymal cell attachment to both composites and polymer could be comparable with a non-degrading positive Thermanox control. These studies indicate that the filled formulations may be good candidates for bone repair. Release of calcium and phosphate ions provides components essential for such repair.
用核磁共振、傅里叶变换红外线光谱、拉曼、X 射线粉末衍射和重量分析研究了聚（丙交酯-乙交酯-co-丙交酯）二甲基丙烯酸酯胶粘剂的初始结构、设定和降解过程，该胶粘剂填充了 50、60 或 70wt%的反应性磷酸钙（一水磷酸一钙（MCPM）/β-磷酸三钙（β-TCP））。填料的加入略微降低了快速光激活单体聚合速率，但没有降低最终水平。在水中浸泡 24h 后，由于吸水，设定的复合质量和体积增加。这促进了初始可溶性 MCPM 从复合材料表面的损失，但也促进了其在标本内部的反应和磷灰石沉淀。48h 后，复合材料的重量和化学研究与聚合物的表面侵蚀和反应/剩余填料一致。填充配方比未填充聚合物表现出更快的早期吸水和随后的表面侵蚀。钙和磷酸盐的释放曲线和溶液 pH 值测量证实了表面 MCPM 与聚合物降解产物质子的早期损失。在以后的时间里，磷灰石/β-TCP 的释放速度较慢，复合材料的储存溶液的 pH 值约为 5，而未填充聚合物的 pH 值约为 3.2。填料的加入增加了早期和后期材料模量。在中间时间，这种效应消失了，可能是由于吸水增强。早期获得的模量值落在报道的松质骨范围内。尽管存在表面降解，但初始人间充质细胞对两种复合材料和聚合物的附着都可以与非降解的阳性 Thermanox 对照相媲美。这些研究表明，填充配方可能是骨修复的良好候选物。钙和磷酸盐离子的释放为这种修复提供了必需的成分。
