Wang H, Qin X Y, Li Z Y, Zheng Z Z, Fan T Y
The State Key Laboratory of Natural and Biomimetic Drugs, Beijing Key Laboratory of Molecular Pharmaceutics and New Drug Delivery Systems, Peking University School of Pharmaceutical Sciences, Beijing 100191, China.
Department of Nuclear Medicine, Beijing Tsinghua Changgung Hospital, Beijing 100044, China.
Beijing Da Xue Xue Bao Yi Xue Ban. 2018 Apr 18;50(2):340-346.
To prepare and characterize citric acid (CA)-modified super paramagnetic iron oxide nanoparticles (SPIONs) for magnetic targeting, hyperthermia and magnetic resonance imaging (MRI).
CA-modified SPIONs (CA-SPIONs) were prepared by co-precipitation method and then the magnetic responsiveness, morphology, particle size, infrared feature, weight percentage of CA, magnetic property and X-ray diffraction pattern of CA-SPIONs were respectively characterized by magnet, transmission electron microscope, laser particle size analyzer, Fourier transform infrared (FT-IR) spectroscopy, thermogravimetry-differential thermal analyzer, vibrating sample magnetometer and X-ray diffractometer (XRD). The heating efficiency of the CA-SPIONs was investigated by a high frequency induction heater. The transverse relaxivity (r2) of the CA-SPIONs was evaluated by a 3.0 T MRI scanner.
The CA-SPIONs prepared were dispersed well in water with a dark black color and had good magnetic responsiveness. The CA-SPIONs were spherical in shape and uniform in size with an average size around 12 nm. The hydrodynamic average size of the CA-SPIONs was (72.35±4.47) nm with a polydispersity index of 0.231 ± 0.029. The result of infrared spectrum indicated that CA was successfully modified to the surface of SPIONs. The result of thermogravimetric analysis showed that the weight percentage of CA modified on the CA-SPIONs was 9.0%. The result of magnetic property evaluation demonstrated that the CA-SPIONs exhibited excellent superparamagetism with a saturation magnetism of 63.58 emu/g. The XRD result indicated that the CA-SPIONs were in inverse spinel structure. The crystallite size of the CA-SPIONs was calculated to be 12.4 nm by Debye-Scherrer equation. Under the high frequency alternating electromagnetic field with electric current of 9 A and frequency ranging from 45 to 50 kHz, the CA-SPIONs exhibited excellent heating efficiency and the specific absorption rate (SAR) value was calculated to be 26 W/g. The r2 of the CA-SPIONs was assessed to be 338 (mmol/L)×s by a 3.0 T MRI scanner, which suggested the excellent negative contrast enhancement effect of the CA-SPIONs.
The CA-SPIONs are expected to be used as a promising agent for magnetic targeting, hyperthermia and MRI detection.
制备并表征柠檬酸（CA）修饰的超顺磁性氧化铁纳米粒子（SPIONs），用于磁靶向、热疗及磁共振成像（MRI）。
采用共沉淀法制备CA修饰的SPIONs（CA-SPIONs），然后分别用磁铁、透射电子显微镜、激光粒度分析仪、傅里叶变换红外（FT-IR）光谱仪、热重-差示热分析仪、振动样品磁强计及X射线衍射仪（XRD）对CA-SPIONs的磁响应性、形态、粒径、红外特征、CA重量百分比、磁性及X射线衍射图谱进行表征。用高频感应加热器研究CA-SPIONs的加热效率。用3.0 T MRI扫描仪评估CA-SPIONs的横向弛豫率（r2）。
制备的CA-SPIONs在水中分散良好，呈深黑色，具有良好的磁响应性。CA-SPIONs呈球形，尺寸均匀，平均粒径约为12 nm。CA-SPIONs的流体动力学平均粒径为（72.35±4.47）nm，多分散指数为0.231±0.029。红外光谱结果表明CA成功修饰到了SPIONs表面。热重分析结果显示修饰在CA-SPIONs上的CA重量百分比为9.0%。磁性评估结果表明CA-SPIONs表现出优异的超顺磁性，饱和磁化强度为63.58 emu/g。XRD结果表明CA-SPIONs为反尖晶石结构。根据德拜-谢乐方程计算出CA-SPIONs的微晶尺寸为12.4 nm。在电流为9 A、频率范围为45至50 kHz的高频交变电磁场下，CA-SPIONs表现出优异的加热效率，比吸收率（SAR）值计算为26 W/g。用3.0 T MRI扫描仪测得CA-SPIONs的r2为338（mmol/L）×s，这表明CA-SPIONs具有优异的阴性对比增强效果。
CA-SPIONs有望作为一种有前景的试剂用于磁靶向、热疗及MRI检测。
