骨形态发生蛋白2壳聚糖纳米缓释载体的制备及性能测定

目的 制备负载骨形态发生蛋白2（BMP-2）的壳聚糖纳米球,测定纳米球粒径、zeta电位、形态、体外降解和体外释放性能,探讨负载BMP-2的壳聚糖纳米球作为缓释载体的可行性。方法以壳聚糖（chitosan）和三聚磷酸钠(tripolyphosphate )为原料,采用离子交联法制备壳聚糖纳米球。应用纳米粒度分析仪及zeta电位测定仪检测微球粒径、分布及zeta电位,透视电镜下测定其表面形态。Elisa法测定包封率、载药率及体外释放率。采用SPSS19.0软件包对数据进行统计学分析。结果离子交联法制备的BMP-2壳聚糖纳米球成球形好,球形较规则,分散较均匀,无团聚,表面较光滑;平均粒径为150.85 nm,分散指数PI=0.37,Zeta电位为+35.42 mV,包封率为(68.24±3.83)%,载药率为(56.83±2.26)%。体外释药试验显示,BMP-2可从壳聚糖纳米微球中缓慢释放,释放行为符合双相动力学规律,释放过程可达30 d。结论以壳聚糖和三聚磷酸钠为原料,可成功制备具有良好缓释能力的BMP-2纳米球,为组织工程骨的进一步应用提供依据。

Preparation and examination of BMP-2 loaded chitosan nanospheres in vitro

PURPOSE: To prepare chitosan nanospheres for loading of BMP-2 and to evaluate its size, zeta potential, appearance, degradation and release characteristic in vitro, and then to investigate its feasibility as a carrier for sustained release of BMP-2. METHODS: The BMP-2 loaded chitosan nanospheres were prepared using ionic crosslinking method with tripolyphosphate (TPP) and chitosan. Transmission electron microscope was used to evaluate the morphological properties, and laser particle size analyzer was used to analyze particle size, Zeta potential and distribution. Lysozyme degradation experiment was performed to assess the biodegradation behavior. ELISA assay was used to determine the loading efficiency, encapsulation efficiency and in vitro drug release kinetics. The data was analyzed by SPSS 19.0 software package. RESULTS: The BMP-2 loaded chitosan nanospheres were spherical in shape, smooth on surface and uniform dispersion without aggregation. The mean diameter was 150.85 nm. The dispersion index was 0.37, and zeta potential was +35.42 mV. The average loading efficiency and encapsulation efficiency were (56.83±2.26)% and (68.24±3.83)%, respectively. Release experiment in vitro showed that the releasing property of BMP-2 loaded chitosan nanospheres was consistent with two-phase kinetic regulation and BMP-2 was controlled to release from the chitosan nanospheres over 30 days. CONCLUSIONS: The BMP-2 loaded chitosan nanospheres prepared by ionic crosslinking method are successfully prepared which show a good controlled release property. It provides the basis for further application in bone tissue engineering.