A novel strategy was developed for the detection of methotrexate (MTX) via the quenching effect of MTX on the fluorescence intensity of terbium-doped dendritic silica particles (Tb@KCC-1). The fluorescence intensity of Tb@KCC-1 can be effectively quenched by MTX at 546 nm under an excitation wavelength of 233 nm. The quenched fluorescence is proportional to the amount of MTX in both plasma and exhaled breath condensate (EBC) samples. Under the optimal conditions, the linear dynamic ranges of the developed method were 44 nM to 2.2 μM for EBC, 44 nM to 0.22 μM and 0.22–2.2 μM for plasma samples. The limit of detection (LOD) and limit of quantification (LOQ) in both plasma and EBC media are 35 and 116 nM, respectively. The developed method has the benefits of fast analysis time, simple approach, high specificity, and sensitivity for the detection of MTX in both media. This nanoprobe has been successfully utilized for the quantification of MTX in patients' plasma and spiked EBC samples, proving the applicability of the nanoprobe for MTX detection in real samples.

中文翻译：

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基于铽掺杂二氧化硅树枝状探针的抗肿瘤药物甲氨蝶呤的超灵敏荧光检测

一种新的策略，用于检测甲氨蝶呤（MTX）的开发通过MTX对掺铽树枝状二氧化硅颗粒（Tb@KCC-1）荧光强度的猝灭效应。Tb@KCC-1的荧光强度可以在233 nm激发波长下被MTX在546 nm处有效猝灭。淬灭的荧光与血浆和呼出气冷凝物 (EBC) 样品中 MTX 的量成正比。在最佳条件下，所开发方法的线性动态范围对于 EBC 为 44 nM 至 2.2 μM，对于血浆样品为 44 nM 至 0.22 μM 和 0.22–2.2 μM。血浆和 EBC 介质中的检测限 (LOD) 和定量限 (LOQ) 分别为 35 和 116 nM。所开发的方法具有分析时间快、方法简单、特异性高、对两种培养基中 MTX 检测灵敏度高的优点。