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目的:以Fe3O4磁性纳米粒(Fe3O4magnetic nanoparticle,Fe3O4-MNP)和聚乳酸-聚乙醇酸共聚物(poly lactide-co-glycolide,PLGA)为材料,制备载IL-2磁性纳米颗粒(IL-2-loaded magnetic nanoparticle,IL-2-Fe3O4-PLGA),观察其在肿瘤免疫治疗中的靶向富集作用。方法:采用复乳法制备IL-2-Fe3O4-PLGA,激光粒度分析仪和扫描电镜观察其大小和形态。ELISA检测IL-2-Fe3O4-PLGA的包封率、体外释药特性;MTT法检测其释放IL-2的生物学活性。构建S180肉瘤细胞小鼠肿瘤模型,研究其瘤体内注射联合体外磁场对S180细胞移植瘤生长的影响,普鲁士蓝染色观察IL-2-Fe3O4-PLGA在肿瘤组织以及肝脏和肾脏组织中的富集和分布。结果:成功制备了IL-2-Fe3O4-PLGA,IL-2-Fe3O4-PLGA呈圆球形,平均粒径为(697±0.51)nm,包封率为(83.76±1.24)%。IL-2-Fe3O4-PLGA突释期释放的IL-2质量浓度为100 ng/ml,第15 d后质量浓度为180 ng/ml,并且保持原有生物学活性的85%～55%。在肿瘤组织中,IL-2-Fe3O4-PLGA联合体外磁场组可见大量的普鲁士蓝染色阳性IL-2-Fe3O4-PLGA颗粒沉积,IL-2-Fe3O4-PLGA组只有少量的IL-2-Fe3O4-PLGA阳性颗粒沉积;两组肝脏中均可偶见少量阳性颗粒沉积,而肾脏几乎未见IL-2-Fe3O4-PLGA颗粒沉积。结论:载IL-2磁性纳米颗粒IL-2-Fe3O4-PLGA具有缓释IL-2的功能,联合体外磁场可有效富集于肿瘤组织中。
OBJECTIVE: To prepare IL-2-loaded magnetic nanoparticles (Fe3O4-MNPs) and polylactide-co-glycolide (PLGA) loaded magnetic nanoparticle, IL-2-Fe3O4-PLGA) were used to observe the effect of targeted enrichment in tumor immunotherapy. Methods: IL-2-Fe3O4-PLGA was prepared by double emulsion method. The size and morphology of IL-2-Fe3O4-PLGA were observed by laser particle size analyzer and scanning electron microscope. The encapsulation efficiency and in vitro release characteristics of IL-2-Fe3O4-PLGA were detected by ELISA. The biological activity of releasing IL-2 was detected by MTT assay. The tumor model of S180 sarcoma mouse was constructed to study the effect of in vivo injection combined with in vitro magnetic field on the growth of S180 cell xenografts. Prussian blue staining was used to observe the enrichment of IL-2-Fe3O4-PLGA in tumor and liver and kidney distributed. Results: IL-2-Fe3O4-PLGA was successfully prepared. The average particle size of IL-2-Fe3O4-PLGA was (697 ± 0.51) nm and the encapsulation efficiency was (83.76 ± 1.24)%. The concentration of IL-2 released from IL-2-Fe3O4-PLGA during burst release was 100 ng / ml, the concentration of IL-2 was 180 ng / ml after 15 days, and maintained 85% -55% of the original biological activity. In the tumor tissue, a large number of Prussian blue staining-positive IL-2-Fe3O4-PLGA particles could be seen in the combination of IL-2-Fe3O4-PLGA with in vitro magnetic field. Only a small amount of IL-2-Fe3O4- PLGA-positive particles were deposited; a small amount of positive particles could be occasionally seen in both groups of liver, but almost no deposition of IL-2-Fe3O4-PLGA particles in kidney. CONCLUSION: The IL-2 magnetic nanoparticle IL-2-Fe3O4-PLGA has the function of sustained release of IL-2. Combined with the in vitro magnetic field, it can be effectively enriched in tumor tissue.