Herein, a multifunctional aptamer probe mediated cascade amplification strategy has been constructed for sensitive and label-free detection of adenosine. First, the multifunctional aptamer probe was designed with an aptamer for adenosine identification and a template for cascade amplification. These two regions could partially hybridize with each other and formed a stem-loop structure. Thus, in the absence of adenosine, the probe could be inhibited by itself and the interference signals could be reduced effectively. In the presence of adenosine, the probe identified the adenosine, resulting in the conformational transformation and the release of the template. Then, the 3′-end of the probe-adenosine complex acted as primer to trigger the cascade amplification of strand displacement amplification (SDA) and catalytic hairpin assembly (CHA), yielding a lot of G-quadruplex. Finally, by inserting N-methy mesoporphyrin IX (NMM), an enhanced and label-free fluorescence signal was achieved. This strategy suggested a high sensitivity with a detection limit of 1.3 × 10⁻⁷ mol/L that attributes to the low interference signals of the probe and the amplification capability of the cascade amplification. Moreover, adenosine analysis in human urines was performed, indicating that this method was reliable and could be further used in the early clinical diagnosis and medical research.

在此，已经构建了多功能适体探针介导的级联扩增策略，用于腺苷的敏感和无标记检测。首先，设计多功能适体探针，该适体探针具有用于腺苷鉴定的适体和用于级联扩增的模板。这两个区域可以彼此部分杂交并形成茎环结构。因此，在不存在腺苷的情况下，探针可以被自身抑制并且可以有效地减少干扰信号。在存在腺苷的情况下，探针鉴定出腺苷，导致构象转化和模板的释放。然后，探针-腺苷复合物的3'-末端充当引物，触发链置换扩增（SDA）和催化发夹装配（CHA）的级联扩增，产生大量的G-四链体。最后，通过插入N-甲基中卟啉IX（NMM），获得了增强的且无标记的荧光信号。此策略表明检测限为1.3×10，灵敏度高^-7  mol / L归因于探针的低干扰信号和级联扩增的扩增能力。此外，对人尿液中的腺苷进行了分析，表明该方法是可靠的，可进一步用于早期临床诊断和医学研究。