Abstract: Nano-hydroxyapatite/bacterial cellulose (nano-HA/BC) composite, obtained by depositing in simulated body fluid, is expected to have potential applications in tissue engineering. The in-vitro degradation performance and the corresponding mechanism of nano-HA/BC immersed in phosphate buffer solution (PBS) are investigated with several flakes of nano-HA/BC soaked in PBS for different time. The degradation degree of materials, the stability of nano-HA particles and the swelling and structural changes of BC are analysed successively. The results indicate that nano-HA particles are able to dissolve or drop off gradually and that water molecules attack the BC fibrils. So the bonding strength of molecular chains is weakened and the partial C?O?C bonds disconnect. The disconnection of C?O?C bonds is considered as the primary reason for the degradation of BC large molecular chains after nHA/BC is immersed in PBS. The present work is available for controlling the in vivo degradation performance of nHA/BC acting as bone tissue engineered scaffold materials.

Key words: nano-hydroxyapatite/bacterial cellulose, degradation, phosphate buffer solution

摘要： 将细菌纤维素浸泡在模拟体液中沉积而形成的纳米羟基磷灰石/细菌纤维素复合材料(nano-HA/BC), 被认为是在骨组织工程领域中理想的支架材料。从以下几方面分析nano-HA/BC在磷酸盐缓冲液(PBS)中浸 泡不同时间后的降解行为及其相应的机制: 材料的降解程度、nano-HA颗粒的稳定性和BC的结构变化。结果表明, nano-HA/BC 在PBS溶液中浸泡一定时间后, nano-HA颗粒会逐渐溶解或脱落, 水分子直接与BC纤维丝相互作用。在水分子和离子的作用下, BC的结晶度降低, BC分子链中分子间和分子内的结合力降低, 甚至部分非结晶区内C?O?C键断裂。而C?O?C键的断裂是nHA/BC在PBS溶液中BC大分子降解的主要机制。研究结果对于研究骨组织工程支架材料nHA/BC的体内降解行为具有重要的指导意义。

关键词: 纳米羟基磷灰石/细菌纤维素, 降解, 磷酸盐缓冲液