To understand the biological effects of Thorium-232 (Th) in human cells and animal models as well as to assess mitigation strategies for its detoxification, there is a need to develop a sensitive, specific, high-throughput and easily-implementable assay for detection and estimation of Th in biological samples. Here, we have optimized arsenazo-III dye based colorimetric assay to detect Th in biological samples. The concentration of arsenazo-III (i.e. 50 µM) was optimized, which can reliably estimate Th in the concentration range of 2.5 to 40 µM. The optimized assay can specifically detect Th without interference from other metal ions (La, Ce, U, Fe, Ca, Cu, Zn and Mn). A significant correlation (R2 = 0.999) was found between arsenazo-III-based detection of Th and total reflection X-ray fluorescence. The conditions of present assay successfully estimated Th in cell culture medium, cell harvesting (trypsin-EDTA) solution and cell lysate obtained from human liver cell culture. Moreover, for the first time, we detected Th in-situ in adherent liver cells in culture after staining with arsenazo-III. This study confirms that Th can be specifically determined in biological samples using arsenazo-III with the sensitivity, which is relevant to thorium toxicity research.

中文翻译：

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通过基于砷偶氮-III的比色测定估算和原位检测人肝细胞培养物中的th。

为了了解Thorium-232（Th）在人类细胞和动物模型中的生物学效应以及评估其解毒的缓解策略，需要开发一种灵敏，特异性，高通量且易于实施的检测方法和估算生物样品中的Th。在这里，我们优化了基于砷偶氮-III染料的比色测定法，以检测生物样品中的Th。优化了砷偶氮-III（即50 µM）的浓度，可以在2.5至40 µM的浓度范围内可靠地估算Th。优化的检测方法可以特异性检测Th，而不受其他金属离子（La，Ce，U，Fe，Ca，Cu，Zn和Mn）的干扰。在基于砷偶氮-III的Th检测与全反射X射线荧光之间发现显着相关性（R2 = 0.999）。本测定的条件成功地估计了从人肝细胞培养物中获得的细胞培养基，细胞收获液（胰蛋白酶-EDTA）溶液和细胞裂解液中的Th。此外，我们首次用砷酰偶氮-III染色后在培养物中的粘附肝细胞中原位检测到Th。这项研究证实，使用砷偶氮-III可以灵敏地确定生物样品中的Th，这与th毒性研究有关。