This study presents a fluorescence method for detecting adenosine triphosphate (ATP) based on a label-free Ag nanocluster molecular beacon (MB) with high sensitivity. The sensor contains a hairpin-shaped MB, two short single-stranded DNA strands, and T4 DNA ligase. The MB consists of three parts, which are the template DNA sequence for synthesizing Ag nanoclusters at the 5′ end, the middle DNA with a hairpin-shaped structure, and the guanine base-rich DNA sequence at the 3′ end. The sensor exhibits high fluorescence intensity in the absence of ATP. However, when the probe is used for ATP detection, the two short DNA sequences in the sensor would form a long sequence by enzymatic ligation reaction; this long sequence opens the hairpin-shaped structure of the MB and decreases the fluorescence of the system. Under optimal analytical conditions, a clear linear relationship is observed between ATP concentration and fluorescence intensity in the range of 0.1–10 μM. The interference presented by other small molecules during ATP detection is evaluated, and results confirm the good selectivity of the proposed sensor. Compared with traditional methods, the sensor is label free, easy to operate, inexpensive, and highly sensitive.

中文翻译：

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用于三磷酸腺苷检测的Ag纳米簇分子信标的设计与合成。

这项研究提出了一种基于高灵敏度的无标记Ag纳米簇分子信标（MB）的荧光检测三磷酸腺苷（ATP）的方法。该传感器包含一个发夹形的MB，两条短的单链DNA链和T4 DNA连接酶。MB由三部分组成，分别是用于在5'端合成Ag纳米簇的模板DNA序列，具有发夹形结构的中间DNA和在3'端富含鸟嘌呤碱基的DNA序列。在没有ATP的情况下，传感器显示出高荧光强度。但是，当探针用于ATP检测时，传感器中的两个短DNA序列将通过酶促连接反应形成一个长序列。这种长序列打开了MB的发夹形结构，并降低了系统的荧光。在最佳分析条件下，ATP浓度与荧光强度之间在0.1–10μM之间存在明显的线性关系。评估了其他小分子在ATP检测过程中产生的干扰，结果证实了所提出传感器的良好选择性。与传统方法相比，该传感器无标签，易于操作，价格便宜且高度敏感。