Materials with a high atomic number (Z) are shown to cause an increase in the level of cell kill by ionizing radiation when introduced into tumor cells. This study uses in vitro experiments to investigate the differences in radiosensitization between two cell lines (MCF‐7 and U87) and three commercially available nanoparticles (gold, gadolinium, and iron oxide) irradiated by 6 MV X‐rays. To assess cell survival, clonogenic assays are carried out for all variables considered, with a concentration of 0.5 mg mL−1 for each nanoparticle material used. This study demonstrates differences in cell survival between nanoparticles and cell line. U87 shows the greatest enhancement with gadolinium nanoparticles (2.02 ± 0.36), whereas MCF‐7 cells have higher enhancement with gold nanoparticles (1.74 ± 0.08). Mass spectrometry, however, shows highest elemental uptake with iron oxide and U87 cells with 4.95 ± 0.82 pg of iron oxide per cell. A complex relationship between cellular elemental uptake is demonstrated, highlighting an inverse correlation with the enhancement, but a positive relation with DNA damage when comparing the same nanoparticle between the two cell lines.

中文翻译：

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放射治疗后纳米粒子的放射生物学意义

当被引入肿瘤细胞时，具有高原子序数 (Z) 的材料会通过电离辐射导致细胞杀伤水平增加。本研究使用体外实验来研究经 6 MV X 射线照射的两种细胞系（MCF-7 和 U87）和三种市售纳米颗粒（金、钆和氧化铁）之间的放射增敏差异。为评估细胞存活率，对所有考虑的变量进行克隆形成分析，每种使用的纳米颗粒材料的浓度为 0.5 mg mL-1。该研究表明纳米颗粒和细胞系之间的细胞存活率存在差异。U87 显示钆纳米粒子的最大增强 (2.02 ± 0.36)，而 MCF-7 细胞使用金纳米粒子 (1.74 ± 0.08) 具有更高的增强。然而，质谱 显示氧化铁和 U87 细胞的最高元素吸收，每个细胞含有 4.95 ± 0.82 pg 氧化铁。证明了细胞元素吸收之间的复杂关系，突出显示与增强呈负相关，但在比较两种细胞系之间的相同纳米颗粒时与 DNA 损伤呈正相关。