A lanthanide complex based on europium (Eu) and chelidamic acid was synthesized (Eu–CHE) and characterized. The complex Eu–CHE exhibited intense luminescence at 615 nm under excitation at 300 nm and was further investigated for highly sensitive turn‐off detection of l‐kynurenine (l‐kyn), a cancer biomarker. The probe detected l‐kyn linearly from 6 nM to 0.2 μM with a limit of detection and limit of quantification of 1.37 and 4.57 nM, respectively. The probe was investigated for selectivity towards l‐kyn among co‐existing amino acids and further extended for detecting l‐kyn from human serum and urine samples. A low‐cost paper strip‐based sensing platform was also developed for the visual detection of l‐kyn.

中文翻译：

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高灵敏度镧系元素络合物作为 L-犬尿氨酸探针：癌症生物标志物

合成了基于铕 (Eu) 和白屈菜酸的镧系元素配合物 (Eu-CHE) 并进行了表征。复合物 Eu-CHE 在 300 nm 激发下在 615 nm 处表现出强烈的发光，并进一步研究了其高灵敏度关闭检测我‐犬尿氨酸（我‐kyn），一种癌症生物标志物。探头检测到我‐kyn 从 6 nM 线性至 0.2 μM，检测限和定量限分别为 1.37 和 4.57 nM。研究了探针的选择性我‐kyn 位于共存氨基酸中并进一步扩展用于检测我‐kyn 来自人类血清和尿液样本。还开发了一种基于纸条的低成本传感平台，用于视觉检测我‐kyn。