Department of Chemical and Materials Engineering, National Yunlin University of Science and Technology, 123, University Rd, Sec. 3, Douliu, Yunlin 64002, Taiwan, Republic of China.
Phys Med Biol. 2010 Jan 21;55(2):469-82. doi: 10.1088/0031-9155/55/2/009. Epub 2009 Dec 21.
We investigated iron oxide nanoparticles with two different surface modifications, dextran coating and cross-linked dextran coating, showing that their different internalization affects their capability to enhance radiation damage to cancer cells. The internalization was monitored with an ultrahigh resolution transmission x-ray microscope (TXM), indicating that the differences in the particle surface charge play an essential role and dominate the particle-cell interaction. We found that dextran-coated iron oxide nanoparticles cannot be internalized by HeLa and EMT-6 cells without being functionalized with amino groups (the cross-linked dextran coating) that modify the surface potential from -18 mV to 13.4 mV. The amount of cross-linked dextran-coated iron oxide nanoparticles uptaken by cancer cells reached its maximum, 1.33 x 10(9) per HeLa cell, when the co-culture concentration was 40 microg Fe mL(-1) or more. Standard tests indicated that these internalized nanoparticles increased the damaging effects of x-ray irradiation, whereas they are by themselves biocompatible. These results could lead to interesting therapy applications; furthermore, iron oxide also produces high contrast for magnetic resonance imaging (MRI) in the diagnosis and therapy stages.
我们研究了两种不同表面修饰的氧化铁纳米粒子，葡聚糖涂层和交联葡聚糖涂层，结果表明它们不同的内化方式会影响它们增强癌细胞辐射损伤的能力。用超分辨率透射 X 射线显微镜（TXM）监测内化情况，表明颗粒表面电荷的差异起着至关重要的作用，并主导着颗粒-细胞相互作用。我们发现，没有用将表面电势从-18 mV 修饰为 13.4 mV 的氨基（交联葡聚糖涂层）功能化的葡聚糖包覆的氧化铁纳米粒子不能被 HeLa 和 EMT-6 细胞内化。当共培养浓度为 40 μg Fe mL（-1）或更高时，癌细胞摄取的交联葡聚糖包覆的氧化铁纳米粒子的量达到最大值，为 1.33×10（9）个/HeLa 细胞。标准测试表明，这些内化的纳米粒子增加了 X 射线照射的破坏作用，而它们本身是生物相容的。这些结果可能会导致有趣的治疗应用；此外，氧化铁在诊断和治疗阶段也会产生磁共振成像（MRI）的高对比度。
