功能性组织工程支架材料复合微粒的制备分离方法比较

背景生物相容性是药物缓释系统的一个关键指标,除了材料本身具有生物相容性以外,微球的球形度和表面光洁度对生物相容性也有很大影响.目的获得球形度较高且表面光滑的聚乳酸乙醇酸共聚物微球,提高微球的生物相容性.设计开放性实验.单位暨南大学生物材料研究室.材料实验于2004-06/2005-01在暨南大学生物材料研究室完成.材料有聚乳酸乙醇酸共聚物,溶菌酶,聚乙烯醇,其他试剂均为分析纯.仪器匀浆机,超声波清洗仪,机械搅拌机,扫描电镜,原子力显微镜.方法①微球制备采用双乳液法制备聚乳酸乙醇酸共聚物微球,溶菌酶为模型蛋白药物.采用3种分离方法(直接冷冻干燥法、过滤法、离心法)收集产品,洗涤,真空冷冻干燥.②扫描电镜观察观察3种分离方法对微球形态的影响.所有的样品都经过镀铜台以及喷金处理,然后再进行电镜观察.③原子力显微镜观察通过原子力显微镜对微球的表面形态结构进行分析.结果①扫描电镜观察结果与直接冷冻干燥法和过滤法相比,离心处理的方法对获取球形度较高且表面光滑的聚乳酸乙醇酸共聚物微球更为有效,而超声分散对微球的形态结构造成影响.②原子力显微镜观察结果表明微粒表面光滑平整,平均粗糙度为48.55 nm.结论通过观察不同的下游处理过程对微球分离制备的影响,能够获得球形度高且表面光滑的产品.此外,根据实验过程中微粒的形成与支架的构建同步这一结果,提出了一步法这一新方法用于构建与微粒结合有关的组织工程支架材料.

Comparison of ways of separating combined microparticles in functional tissue engineering scaffold

BACKGROUND:Biocompatibility is a key parameter in drug delivery systems. In general, to obtain a proper microparticle carrier, the materials themselves should have excellent biocompatibility. Besides, spherical degree and surface smoothness both have significant influence on biocompatibility.OBJECTIVE: To obtain spherical and smooth poly (lactide-co-glycolide)microparticles, so as to improve the property of biocompatibility.DESIGN: Open experiment.SETTING: Research Laboratory of Biomaterials, Jinan University.MATERIALS: The experiment was conducted in the Research Laboratory of Biomaterials, Jinan University, between June 2004 and January 2005.The materials included poly(lactide-co-glycolide), lysozyme and poly (vinyl alcohol). The other reagents were analytical pure. The instruments included a homogenizer, a mechanical stirrer, an ultrasonic cleaning instrument, a scanning electron microscope and an atomic force microscope.METHODS: ① Preparation of microparticles: Lysozyme was selected as a model protein for encapsulation into poly(lactide-co-glycolide) using a dou-ble emulsion solvent extraction/evaporation method. Three separation methods, namely direct vacuum freeze-drying, filtration and centrifugation,were investigated and compared. ② Observation under the scanning electron microscope: We observed the effect of three separation methods on the shape of microparticles. All the samples were attached to copper mounts and coated with gold, and then were observed with an electron microscope.③ Observation under the atomic force microscope: The morphological structure of the surface was analyzed with atomic force microscope.RESULTS: ① Observation results of scanning electron microscope: Compared with direct vacuum freeze-drying and filtration, centrifugation method was more efficacious in obtaining spherical and smooth microparticles based on the scanning electron microscope pictures. But results also warned us to be more careful when we prepared scanning electron microscope samples using ultrasonic to separate the aggregates. ② Atomic force microscope results indicated that the surface was smooth with the average roughness of 48.55 nm.CONCLUSION: By investigating the influence of different downstream processes, we can obtain spherical and smooth products. Besides, a new one-step method is put forward in constructing some microparticle-combined polymer based scaffolds because the combined scaffolds and microparticles are formed synchronously.