Department of Chemistry and Pharmacy, Physical Chemistry I and ICMM, Friedrich-Alexander University of Erlangen, Egerlandstr. 3, D-91058, Erlangen, Germany.
Department of Material Science, Institute of Polymer Materials, Friedrich-Alexander University of Erlangen, Martensstr. 7, D-91058, Erlangen, Germany.
Small. 2018 May;14(21):e1704111. doi: 10.1002/smll.201704111. Epub 2018 Apr 18.
Efficient magnetic reactive oxygen species (ROS) formation enhancing agents after X-ray treatment are realized by functionalizing superparamagnetic magnetite (Fe O ) and Co-ferrite (CoFe O ) nanoparticles with self-assembled monolayers (SAMs). The Fe O and CoFe O nanoparticles are synthesized using Massart's coprecipitation technique. Successful surface modification with the SAM forming compounds 1-methyl-3-(dodecylphosphonic acid) imidazolium bromide, or (2-{2-[2-hydroxy-ethoxy]-ethoxy}-ethyl phosphonic acid provides biocompatibility and long-term stability of the Fe O and CoFe O nanoparticles in cell media. The SAM-stabilized ferrite nanoparticles are characterized with dynamic light scattering, X-ray powder diffraction, a superconducting quantum interference device, Fourier transform infrared attenuated total reflectance spectroscopy, zeta potential measurements, and thermogravimetric analysis. The impact of the SAM-stabilized nanoparticles on the viability of the MCF-7 cells and healthy human umbilical vein endothelial cells (HUVECs) is assessed using the neutral red assay. Under X-ray exposure with a single dosage of 1 Gy the intracellular SAM stabilized Fe O and CoFe O nanoparticles are observed to increase the level of ROS in MCF-7 breast cancer cells but not in healthy HUVECs. The drastic ROS enhancement is associated with very low dose modifying factors for a survival fraction of 50%. This significant ROS enhancement effect by SAM-stabilized Fe O and CoFe O nanoparticles constitutes their excellent applicability in radiation therapy.
通过用自组装单层（SAM）对超顺磁磁铁矿（Fe3O4）和钴铁氧体（CoFe2O4）纳米粒子进行功能化，实现了 X 射线治疗后高效的磁反应性氧物种（ROS）形成增强剂。使用 Massart 的共沉淀技术合成 Fe3O4 和 CoFe2O4 纳米粒子。成功地用 SAM 形成化合物 1-甲基-3-（十二烷基膦酸）咪唑溴化物或（2-{2-[2-羟基乙氧基]-乙氧基}-乙基膦酸进行表面修饰，为 Fe3O4 和 CoFe2O4 纳米粒子在细胞培养基中的生物相容性和长期稳定性提供了保障。用动态光散射、X 射线粉末衍射、超导量子干涉装置、傅里叶变换衰减全反射光谱、Zeta 电位测量和热重分析对 SAM 稳定的铁氧体纳米粒子进行了表征。使用中性红测定法评估了 SAM 稳定的纳米粒子对 MCF-7 细胞和健康人脐静脉内皮细胞（HUVEC）活力的影响。在 1 Gy 单次剂量的 X 射线照射下，观察到细胞内 SAM 稳定的 Fe3O4 和 CoFe2O4 纳米粒子增加了 MCF-7 乳腺癌细胞中的 ROS 水平，但对健康的 HUVEC 没有影响。ROS 的急剧增强与 50%存活分数的非常低剂量修饰因子有关。SAM 稳定的 Fe3O4 和 CoFe2O4 纳米粒子的这种显著的 ROS 增强效应构成了它们在放射治疗中的优异适用性。
