Division of Cyclotron and Radiopharmaceutical Sciences, Institute of Nuclear Medicine and Allied Sciences, Defence Research and Development Organisation, Brig. S. K. Mazumdar Marg, Delhi 110054, India.
J Biomed Nanotechnol. 2013 Mar;9(3):323-34. doi: 10.1166/jbn.2013.1548.
The physical and chemical properties of the nanoparticles influence their pharmacokinetics and ability to accumulate in tumors. In this paper we report a facile method to conjugate folic acid molecule to iron oxide nanoparticles to increase the specific uptake of these nanoparticles by the tumor, which will be useful in targeted imaging of the tumor. The iron oxide nanoparticles were synthesized by alkaline co precipitation method and were surface modified with dextranto make them stable. The folic acid is conjugated to the dextran modified iron oxide nanoparticles by reductive amination process after the oxidation of the dextran with periodate. The synthesized folic acid conjugated nanoparticles were characterized for size, phase, morphology and magnetization by using various physicochemical characterization techniques such as transmission electron microscopy, X-ray diffraction, fourier transform infrared spectroscopy, vibrating sample magnetometry, dynamic light scattering and zetasizer etc. The quantification of the generated carbonyl groups and folic acid conjugated to the surface of the magnetic nanoparticles was done by colorimetric estimations using UV-Visible spectroscopy. The in vitro MR studies were carried out over a range of concentrations and showed significant shortening of the transverse relaxation rate, showing the ability of the nanoconjugate to act as an efficient probe for MR imaging. The biodistribution studies and the scintigraphy done by radiolabeling the nanoconjugate with 99mTc show the enhanced uptake at the tumor site showing its enhanced specificity.
纳米粒子的物理和化学性质影响它们的药代动力学和在肿瘤中积累的能力。在本文中，我们报告了一种将叶酸分子偶联到氧化铁纳米粒子上的简便方法，以增加这些纳米粒子被肿瘤特异性摄取的能力，这将有助于肿瘤的靶向成像。氧化铁纳米粒子通过碱性共沉淀法合成，并通过葡聚糖表面修饰使其稳定。葡聚糖用高碘酸盐氧化后，通过还原胺化过程将叶酸偶联到葡聚糖修饰的氧化铁纳米粒子上。通过透射电子显微镜、X 射线衍射、傅里叶变换红外光谱、振动样品磁强计、动态光散射和 Zetasizer 等各种物理化学特性表征技术对合成的叶酸偶联纳米粒子的粒径、相、形貌和磁化进行了表征。使用紫外可见光谱的比色法对生成的羰基和叶酸在磁性纳米粒子表面的偶联进行了定量。在一系列浓度下进行了体外磁共振研究，显示横向弛豫率显著缩短，表明纳米复合物具有作为磁共振成像有效探针的能力。通过用 99mTc 放射性标记纳米复合物进行的生物分布研究和闪烁照相术显示，在肿瘤部位的摄取增强，表明其特异性增强。
