We developed a novel label-free strategy for electrochemical detection thrombin based on rolling circle amplification (RCA) triggering poly adenine production for adsorption gold nanoparticles (AuNPs). In this assay, the aptamer 1 was first immobilized on the gold electrode (GE) surface as the capture probe via poly adenine-Au. Subsequently, the thrombin and the aptamer 2 were deposited on the electrode surface. The aptamer 2 fragment on the sensor surface as a primer hybridized with the RCA template to initiate the RCA process, which generated massive long DNA sequences that contained many adenines. Subsequently, the AuNPs was absorbed on the long-repeated adenines of RCA product, resulting in the multiplication of AuNPs on the electrode surface, which were used for subsequent electrocatalytic reduction of H₂O₂. In this sensing system, the electrochemical signals with the concentration of thrombin over a range from 0.1 pM to 10 nM were detected and the detection limit obtained was 35 fM, and have high selectivity toward its target protein. In addition, due to the high affinity between poly adenine and GE or AuNPs, the detection can be carried out without any fussy modification process, thus had a promising application in clinical diagnosis.

我们开发了一种基于滚动圆环扩增（RCA）触发聚腺嘌呤生产吸附性金纳米颗粒（AuNPs）的电化学检测凝血酶的新型无标记策略。在该测定中，适体1首先通过聚腺嘌呤-Au固定在金电极（GE）表面上作为捕获探针。随后，将凝血酶和适体2沉积在电极表面上。传感器表面的适体2片段作为与RCA模板杂交的引物，启动了RCA过程，该过程产生了包含许多腺嘌呤的大量长DNA序列。随后，AuNPs被RCA产物的长期重复的腺嘌呤吸收，导致AuNPs在电极表面上繁殖，并用于随后的H _2的电催化还原。O ₂。在该传感系统中，检测到凝血酶浓度在0.1 pM至10 nM范围内的电化学信号，检测限为35 fM，并且对目标蛋白具有高选择性。另外，由于聚腺嘌呤与GE或AuNPs之间具有高亲和力，因此无需任何繁琐的修饰过程即可进行检测，因此在临床诊断中具有广阔的应用前景。