装载油酸修饰氧化铁的聚乳酸/羟基乙酸纳米粒的制备、表征及体外MR显像  

Preparation,characterization and in vitro MR imaging of poly(D, L-lactide-co-glycolide acid) nanoparticles loaded with iron oxide nanocrystals with oleic acid coating

作　　者：孙玲[1] 赵建农[1] 郭大静[1] 周君[1] 张瑜[1] 杨静[1] 王志刚[2] 

机构地区：[1]重庆医科大学附属第二医院放射科,重庆400010 [2]重庆医科大学超声影像学研究所,重庆400010

出　　处：《中国医学影像技术》2013年第1期1-5,共5页Chinese Journal of Medical Imaging Technology

基　　金：国家自然科学基金(81171332)

摘　　要：目的制备装载油酸修饰氧化铁的聚乳酸/羟基乙酸(PLGA)纳米粒(磁性PLGA纳米粒),并对其理化性质进行表征,观察其体外MR显像效果。方法以油酸修饰氧化铁和PLGA-COOH为原料,采用单乳化法制备磁性PLGA纳米粒。以激光共聚焦扫描显微镜及透射电镜观察其表面及内部结构;Malvern激光分析仪测量其粒径大小、分布及表面电位;X射线粉末衍射仪分析其内部物象结构;原子吸收光谱法测量样品中Fe的浓度;热重分析法分析其内装载的Fe3O4的量。将稀释到不同浓度的磁性PLGA纳米粒分别置于Eppendof管中,行MR扫描。结果所得样品为棕色混悬液,大小均匀,粒径为(292.70±77.07)nm,多分散指数为0.009,粒径分布较窄;Zeta电位为(-10.20±4.34)mV;透射电镜和X射线粉末衍射法证实其内包裹大量Fe3O4颗粒;原子吸收光谱法计算得Fe3O4的包封率为39.6%,Fe3O4的负载量为1.036%。体外MR显像显示,所得样品能使T2*信号强度降低,且样本中Fe浓度越大,其信号强度越低。结论制备所得磁性PLGA纳米粒粒径小,分布窄,能有效降低T2*信号强度,为构建潜在多功能MRI分子探针奠定了基础。Objective To prepare biodegradable poly （D, L-lactide-co-glycolide acid） （PLGA） nanoparticles loaded with iron oxide nanocrystals with oleic acid coating, and to explore the effect for in vitro MR imaging. Methods Magnetic PLGA nanoparticles were prepared using modified single oil-in-water emulsion method utilizing iron oxide nanocrystals with oleic acid coating and PLGA-COOH. Laser scanning confocal microscopy （LSCM） and transmission electron microscopy （TEM） analysis were carried out to examine the surface and interior morphology of PLGA nanoparticles. The size, distribution and zeta potential were observed using Malvern laser analyzer. X-ray powder diffraction analysis （XRD） was used to confirm the phase composition. Atomic absorption spectrophotometry （AAS） and thermogravimetry analysis （TG） were carried out to calculate the magnetite entrapment efficiency and magnetite content. Then magnetic PLGA nanoparticles of different Fe concentrations were placed into Eppendof tubes for MR scanning. Results The samples were brown suspended in deionized water, with a mean diameter of （292.70±77.07）nm and a polydispersity index of 0.009. Zeta potential was （-10.20±4.34）mV. TEM photomicrographs showed there were lots of iron oxide nanocrystals loaded inside the PLGA nanoparticles. XRD proved the existence of Fe3O4. The magnetite entrapment efficiency was 39.6%, and magnetite content was 1.036%. MRI showed reduced signal intensity of different samples with different Fe concentrations in the tubes. The higher Fe concentrations was, the lower signal intensity became. Conclusion These developed magnetic PLGA nanoparticles have small size and narrow size distribution, which can effectively decrease T2＊ signal, therefore can be used as a promising multifunctional MRI contrast agent.

关 键 词：磁性氧化铁 纳米粒 磁共振成像 对比剂 

分 类 号：R445.1[医药卫生—影像医学与核医学] R332[医药卫生—诊断学]