Superparamagnetic iron oxide nanoparticles (SPIONs) designed to interact with tumor cells have received increasing interest in the past few years, due to their potential for applications such as magnetic resonance imaging (MRI) contrast enhancement, drug delivery, and hyperthermia. However, the stability of these nanoparticles under physiological conditions, and their ability to selectively target tumor cells are challenges which need to be addressed. In this work, SPIONs were first modified with poly(glycidyl methacrylate) (PGMA) via atom transfer radical polymerization (ATRP). The epoxy groups in PGMA were then reacted with ethylenediamine to generate amino groups, which were conjugated with different amounts of folic acid (FA) for cancer cells targeting. The as-synthesized folic acid conjugated SPIONs (SPIONs–PGMA–FA) are hydrophilic and highly stable in an aqueous medium. The targeting efficiency of the folic acid-conjugated nanoparticles was investigated with different cell lines. The uptake of SPIONs–PGMA–FA by KB (human epidermoid carcinoma) cells is about three and five times higher than that of macrophages and 3T3 fibroblasts, respectively. No significant cytotoxicity was observed when the three types of cells were incubated with nanoparticles at a concentration of 0.5 mg mL−1 or less. The nanoparticles also exhibited high MR enhancement effects with r2 and r2/r1 values of 191.4 mM−1 s−1 and 98 respectively in a 3T magnetic field. Hence, these nanoparticles can potentially be used to selectively target cancer cells for imaging as well as hyperthermia.
由于超顺磁性
氧化铁纳米粒子(
SPIONs)在磁共振成像(MRI)对比度增强、药物输送和热疗等方面的应用潜力,过去几年来,这种能与肿瘤细胞相互作用的超顺磁性
氧化铁纳米粒子越来越受到人们的关注。然而,这些纳米粒子在生理条件下的稳定性及其选择性靶向肿瘤细胞的能力是亟待解决的难题。在这项工作中,首先通过原子转移自由基聚合(ATRP)技术用聚
甲基丙烯酸缩水甘油酯(P
GMA)对
SPIONs 进行改性。然后,P
GMA 中的环氧基团与
乙二胺反应生成
氨基基团,
氨基基团与不同量的叶酸(FA)共轭,用于靶向癌细胞。合成的叶酸共轭
SPIONs(
SPIONs-P
GMA-FA)具有亲
水性,在
水介质中高度稳定。研究人员用不同的
细胞系考察了叶酸共轭纳米粒子的靶向效率。KB(人表皮样癌)细胞对
SPIONs-P
GMA-FA 的吸收率分别是巨噬细胞和 3T3 成纤维细胞的三倍和五倍。当三种细胞与浓度为 0.5 毫克毫升-1 或更低的纳米颗粒一起培养时,未观察到明显的细胞毒性。纳米粒子还表现出较高的磁共振增强效应,在 3T 磁场中的 r2 和 r2/r1 值分别为 191.4 mM-1 s-1 和 98。因此,这些纳米粒子可用于选择性靶向癌细胞成像和热疗。