包封硫酸依替米星壳聚糖／羟基磷灰石纳米缓释骨支架的实验研究

Preparation, characterization and in vitro analysis of etimicin-encapsuled chitosan/hydroxyapatite nano-scaffolds for bone tissue engineering

目的研制一种包封硫酸依替米星壳聚糖／羟基磷灰石纳米缓释骨支架，为临床治疗骨缺损、骨髓炎提供一定帮助。方法离子凝胶法制作载硫酸依替米星的壳聚糖颗粒，载药颗粒结合纳米级羟基磷灰石于模具中成形，采用冻干成孔法制备多孔缓释载药纳米骨支架。使用扫描电子显微镜观察支架表面及其研碎颗粒、X线多晶衍射检测判断其组成、总孔隙率测定以了解其相关表征；进行抑菌实验及长期和累计释药实验了解骨支架抗菌性及缓释性；最后通过骨髓间质干细胞与支架共培养，检测支架的组织相容性。结果载药纳米骨支架为多孔圆柱形颗粒，电镜下其具有纳米级球棒状微观结构，材料表面及内部孔隙分布良好，总孔隙率为70．68％，X线多晶衍射为典型羟基磷灰石波形；抗菌性实验中其抑菌效果可维持1周以上，7d后仍有药物释出；对骨髓间质干细胞无明显抑制作用。结论包封硫酸依替米星壳聚糖，羟基磷灰石纳米缓释骨支架具有与松质骨类似的孔隙结构及组成成分，良好的缓释抗菌效果，可降解，组织相容性好，是较有前景的人工骨替代材料。

Objective To prepare a novel etimicin-encapsuled chitosan/hydroxyapatite nano-seaffolds and offer assistances for bone defect or osteomylitis. Methods Drug-carried chitosan nanoparticles which was prepared by ionotmpic gelation were combined with nano-hydroxyapatite. The mixture were shaped in molds and then prepared into porous scaffolds by freeze-dry. The surface of one scaffold was scanned. The grinded, particles of the scaffold were detected by field emission scanning electron microscope; X-ray diffraction was used to analyze components of the scaffold and total porosity. Staphylococcus anreus was choosed as the experimental bacteria, we studied lasting antibacterial property of drug-carried bone scaffold by antibacterial experiments, long-term drug releasing experiments and accumulation drug releasing experiments. Bone mesenchymal stem cells were used to detect the histocompatibility and inductivity of e- timicin-carried scaffold. Results Freeze-dried porous scaffold has a surface with proper pore distribution （total porosity 70.68%） and the grinded scaffold has a globular and coliformed microstructure known after scanned by electron microscope. The drug-carried scaffold has a typical wave of hydroxyapatite under X-ray diffraction. The lasting antibacterial property study indicated that the drug-carried bone scaffold had maintained an inhibition zone for more than 7 days. The long-term drug releasing experiments and accumulation drug releasing experiments show that the fictional drug-carried bone scaffold released above the bacteriostasis concentration after one week and the accumulative amount within the safety scale. The scaffold had not an inhibitory effect on bone mesenchymal stem cells. Conclusion The etimicin-encapsuled chitosan/hy- droxyapatite nano-scaffolds has similar microstructure and components of bone tissue. It is promising in bone tissue engineering applications because of its slow-release, antibacterial properties and satisfactory histocompatibility.