Li L, Mak K Y, Shi J, Koon H K, Leung C H, Wong C M, Leung C W, Mak C S K, Chan N M M, Zhong W, Lin K W, Wu E X, Pong P W T
Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong.
J Nanosci Nanotechnol. 2012 Dec;12(12):9010-7. doi: 10.1166/jnn.2012.6755.
Magnetic iron oxide nanoparticles (MIONPs) must be biocompatible, and a thorough knowledge on their potential cytotoxicity is crucial for their biomedical applications. However, the detailed study about the effects of iron oxide nanoparticles on cell viability, cell morphology, and cellular uptake of different mammalian cells is still insufficient. In this paper, comparative cytotoxicity study of uncoated magnetite nanoparticles at different concentrations was performed on human cervical cancer cell line (HeLa) and immortalized normal human retinal pigment epithelial cell line (RPE). The size, structure, and magnetic behavior of the MIONPs were characterized using transmission electron microscopy (TEM), X-ray diffractometry (XRD), and vibrating sample magnetometry (VSM) respectively. After 24-hour incubation with the MIONPs, the cell viability was determined by live/dead assay, the cell morphology at high magnification was observed under scanning electron microscopy (SEM), and the cellular uptake of MIONPs was measured under TEM and verified by energy-dispersive X-ray spectroscopy (EDX) analysis. Our results indicate that the uncoated MIONPs at a high concentration (0.40 mg/ml) were toxic to both HeLa and RPE cells. However, the cytotoxicity of uncoated MIONPs at low concentrations was cell-type specific, and RPE cells were more susceptible to these MIONPs than HeLa cells. The effects of the MIONPs on cell morphology and the nanoparticles uptake also showed different features between these two cell lines. Hence cell type should be taken into consideration in the in vitro cytotoxicity study of uncoated MIONPs. Additionally, it should be noticed that the cell morphological changes and the uptake of nanoparticles can take place even though no toxic effect of these MIONPs at low concentrations was reflected in the traditional cell viability assay.
磁性氧化铁纳米颗粒（MIONPs）必须具有生物相容性，全面了解其潜在的细胞毒性对于其生物医学应用至关重要。然而，关于氧化铁纳米颗粒对不同哺乳动物细胞的细胞活力、细胞形态和细胞摄取影响的详细研究仍然不足。本文对人宫颈癌细胞系（HeLa）和永生化正常人视网膜色素上皮细胞系（RPE）进行了不同浓度未包覆磁铁矿纳米颗粒的比较细胞毒性研究。分别使用透射电子显微镜（TEM）、X射线衍射仪（XRD）和振动样品磁强计（VSM）对MIONPs的尺寸、结构和磁性行为进行了表征。与MIONPs孵育24小时后，通过活/死检测确定细胞活力，在扫描电子显微镜（SEM）下观察高倍镜下的细胞形态，并在TEM下测量MIONPs的细胞摄取量，并通过能量色散X射线光谱（EDX）分析进行验证。我们的结果表明，高浓度（0.40 mg/ml）的未包覆MIONPs对HeLa和RPE细胞均有毒性。然而，低浓度未包覆MIONPs的细胞毒性具有细胞类型特异性，RPE细胞比HeLa细胞对这些MIONPs更敏感。MIONPs对细胞形态和纳米颗粒摄取的影响在这两种细胞系之间也表现出不同的特征。因此，在未包覆MIONPs的体外细胞毒性研究中应考虑细胞类型。此外，应该注意的是，即使在传统的细胞活力检测中未反映出低浓度这些MIONPs的毒性作用，细胞形态变化和纳米颗粒摄取仍可能发生。
