BMP-2-PLLA缓释微球的制备及其对BMP-2活性的维持

Preparation of BMP-2-PLLA Microspheres and Its Maintenance for Bioactivity of BMP-2

摘要: 本研究探索载骨形态发生蛋白-2 (BMP-2)的左旋聚乳酸(PLLA)载药微球的制备条件，并检测BMP-2- PLLA微球中BMP-2的释放规律和生物活性。采用乳化法制备载牛血清白蛋白(BSA)的聚乳酸(PLLA)载药微球，考察PLLA分子量、PLLA浓度、PEG分子量对PLLA载药微球粒径、包封率和载药量的影响，选择优化条件制备载BMP-2的PLLA微球，通过细胞合成ALP检测BMP-2的活性。实验制备的BMP-2-PLLA微球表面光滑，粒径为4.815 μm，载药量为2.28 × 10−3%，包封率为70.88%，二氯甲烷残留量为0.0041%。BMP-2-PLLA微球有效实现了BMP-2长期稳定缓慢释。乳化过程未对BMP-2活性产生显著影响，且BMP-2-PLLA微球中释放的BMP-2对细胞合成ALP的诱导作用较BMP-2溶液更加显著。实验制备的PLLA微球可用于负载生长因子实现缓释，并能较好地维持其生物学活性。

Abstract: The preparation conditions of poly-l-lactide (PLLA) microspheres, release characteristics and bi-oactivity of Bone Morphogenetic Protein-2 (BMP-2) were studied. Bovine serum albumin (BSA)- loaded PLLA microspheres were prepared with a double emulsion method. The effects of the mo-lecular weight and concentration of PLLA, the molecular weight of PEG on the particle size, loading capacity and entrapment efficiency were studied. Then, the optimal conditions were selected to prepare BMP-2-loaded PLLA microspheres, and the bioactivity of BMP-2 was investigated by pro-duction of cell Alkaline Phosphatase (ALP). The results showed that the BMP-2-PLLA microspheres were spherical shape with diameters of 4.815 μm. The encapsulation efficiency of the BMP-2 in PLLA microspheres was 70.88%, and the loading capacity was 2.28 × 10−3%. The residual amount of methylene chloride in BMP-2-PLLA microsphere was 0.0041%. BMP-2-loaded PLLA microspheres had excellent drug sustained-release performance, which would control release BMP-2. BMP-2 biological activity indicated that the biological activity was not effected after emulsion process. The bioactivity of growth factors released from PLLA microspheres was more durable and effective. PLLA microspheres prepared can be used to load growth factors to control their release and maintain their biological activity.