【摘要】 采用LbL模板技术,将天然聚电解质壳聚糖CS和海藻酸钠ALG、磁性纳米颗粒Fe3O4或带负电荷或双亲性磷脂在单分散胶体表面进行组装,制备了一种具有热磁双重响应性的新型载药微囊.通过透射电镜、激光共聚焦显微镜、zeta-电位分析仪、紫外分光光度计等对微囊结构及载药、释药性能进行了表征.实验结果表明:微囊的载药量最高可达到22.40%,且具有磁导向作用.微囊外层组装具有热敏性质的磷脂层能有效地克服壳聚糖/海藻酸钠微囊通透性大而导致在较低温(正常生理环境)的输送过程中药物泄漏问题,而在较高温条件下又可使药物迅速释放,从而实现药物的可控释放.更多还原

【Abstract】 A novel targeted carrier of drug loaded microcapsules with thermo- and magnetic-sensitivities was fabricated by the layer-by-layer self-assembly technique. Natural polyelectrolytes such as chitosan and sodium alginate,magnetic nanoparticles Fe3O4,and lipid dipalmitoyl-sn-glycero-3-phosphate ( monosodium salt ) (DPPA),(1,2-dipalmitoyl-sn-glycero-3-phosphocholine) (DPPC) or their composite 10% DPPA/90% DPPC were used as components of microcapsule. The structure,drug loading and thermo-sensitive drug release of the microcapsules were characterized by TEM,SEM,laser scanning confocal microscope and ultraviolet spectrophotometer. The results showed that positive Fe3O4 nanoparticles with superparamagnetic property were successfully assembled on the microcapsules,which could be effectively trapped by solid permanent magnet. The drug entrapment efficiency is affected by the drug concentration and the temperature. The highest drug loading amount could reach to 22. 40% when the temperature reached 60℃ . The drug release properties of microcapsules were measured at 37℃ and 40℃ ,which were lower and higher than the phase transition of DPPA lipid film respectively. The results showed that the microcapsules with lipid film were sensitive to temperature. The thermo-sensitive lipid film assembled on the surface of microcapsule could effectively prevent drug from being released at the lower temperature,which will favor the drug to reach the targeted site with less drug loss.更多还原