We developed a simple, sensitive, low-cost and label-free method to detect microcystin-leucine-arginine (MC-LR) using double-strand DNA-templated copper nanoclusters (dsDNA-CuNCs) as fluorescent probes. The dsDNA template was designed and fabricated by a MC-LR aptamer strand and its complementary strand, which facilitated CuNCs formation and recognized target MC-LR specifically with strong affinity. The formed fluorescent sensing probe of dsDNA-CuNCs exhibited maximum emission wavelength at 575 nm. Upon addition of target MC-LR into dsDNA-CuNCs, fluorescence was quenched considerably due to the high affinity between MC-LR and the aptamer strand, which indicated a conformational change of the dsDNA-CuNCs probe from the dsDNA structure to single-stranded DNA. Then, the change in fluorescence intensity was used to monitor the MC-LR concentration from 0.01 to 1000 μg L⁻¹ with a limit of detection of 4.8 ng L⁻¹. Compared with previous reports, this method did not require design of a complex DNA sequence, fluorescence dye labels or sophisticated experimental techniques. Moreover, the proposed sensing system could be applicable for detection of target MC-LR in real-water samples.

中文翻译：

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基于dsDNA模板铜纳米簇的灵敏检测微囊藻毒素LR的简便荧光策略

我们开发了一种简单，灵敏，低成本且无标签的方法，使用双链DNA模板铜纳米簇（dsDNA-CuNCs）作为荧光探针来检测微囊藻毒素-亮氨酸-精氨酸（MC-LR）。dsDNA模板是由MC-LR适体链及其互补链设计和制造的，MC-LR适体链及其互补链可促进CuNCs的形成，并以强亲和力特异性识别目标MC-LR。形成的dsDNA-CuNCs荧光传感探针在575 nm处显示最大发射波长。将目标MC-LR添加到dsDNA-CuNCs中后，由于MC-LR与适体链之间的亲和力高，荧光被大大淬灭，这表明dsDNA-CuNCs探针的构象从dsDNA结构变为单链DNA 。然后，^-1，检出限为4.8 ng L ^-1。与以前的报告相比，此方法不需要设计复杂的DNA序列，荧光染料标记或复杂的实验技术。此外，所提出的感测系统可适用于检测真实水样中的目标MC-LR。