pH响应性磁靶向纳米复合粒Fe_3O_4@SiO_2@PEG-b-PAsp@DOX的构建及体外评价

Preparation of pH/magnetic dual responsive nanocomplex Fe_3O_4@SiO_2@PEG-b-PAsp@DOX and its cytotoxicity effect on A549 cells

目的制备pH响应性的磁性纳米复合粒多柔比星(doxorubicin,DOX)载体Fe_3O_4@SiO_2@PEG-b-PAsp@DOX并对其理化性质进行表征,考察药物的pH响应性释放、在磁场作用下的靶向性及其对人肺癌A549细胞的杀伤作用。方法利用水热法、Stber方法、溶胶凝胶法、交联法等构建pH响应性载药磁性纳米复合粒Fe_3O_4@SiO_2@PEG-b-PAsp@DOX;利用透射电镜观察其形貌,激光粒度-zeta电位测定仪测定其粒径和zeta电位,磁滞回线测试仪测定其磁性;紫外分光光度法测定载药磁性纳米复合粒的载药量与包封率,透析法测定其pH响应性释药,CCK-8法和AnnexinⅤ-FITC/PI双染法考察其体外对人肺癌A549细胞的杀伤作用。结果 Fe_3O_4@SiO_2@PEG-b-PAsp@DOX载药体系的平均粒径为(197.7±1.5)nm,zeta电位为(-35.9±0.6)mV,载药量(20.36±0.67)%,包封率(83.71±0.53)%。在较低的pH(5.5)下DOX的累积释放量得到提高(P<0.05),在外磁场作用下表现出良好的磁响应性和细胞靶向性,且对人肺癌A549细胞具有显著的杀伤作用。结论 Fe_3O_4@SiO_2@PEG-b-PAsp@DOX具有良好的pH响应性和磁靶向特性,可使药物靶向到达肿瘤部位并控制释放,有效杀伤人肺癌A549细胞。

Objective To prepare doxorubicin-loaded pH/magnetic dual responsive nanocomplex denoted as Fe3O4 @SiO2 @PEG-b-PAsp@DOX and to determine its chemo-physical properties, pH/magnetic dual responsive release, and cytotoxicity against human lung cancer A549 cells. Methods The nanocomplex was synthesized through a sequential process involving hydrothermal treatment, St6ber method, sol gel technique, and cross linking. The morphology, diameter, zeta potential and magnetic properties of the nanocomplex were characterized by transmission electron microscopy, zeta potential measurement analyzer, and hysteresis loop tester, respectively. Drug loading efficiency and encapsulation efficiency were examined by ultraviolet visible absorption spectroscopy; pH-stimulated drug release was investigated by dialysis in vitro; and the anti- proliferative activity apoptosis-induction effect of the complex nanoparticles were investigated by CCK-8 method and flow cytometer, respectively. Results The average particle size of drug-loaded system Fe3 O4 @ SiO2 @ PEG＋PAsp@ DOX was （197.7±1.5） nm and the zeta potential was （-35. 9 ±0. 6） mV. Drug loading efficiency and encapsulation efficiency were （20. 36 ± 0.67）% and （83. 71± 0. 53）%, respectively. Cumulative release rate was significantly increased in mild acid condition （pH =5.5） （P〈0. 05）. The nanocomplex also demonstrated a good magnetic response and targeting ability under outside magnetic field. Moreover, the drug-loaded nanoparticle showed a significant cytotoxicity effect against human lung A549 cells in vitro. Conclusion Fe3O4 @SiO2 @ PEG-b-PAsp@DOX possesses a good pH/magnetic dual responsive release characteristics and exhibits efficient antitumor activity in vitro against lung cancer A549 cells.