Abstract A novel and enzyme-free electrochemical sensor was designed for multiplexed DNA detection based on a surface-confined DNA assembly enabled target recycling amplification. In this designed system, two hairpin DNA probes (hairpin 1 and hairpin 2) were immobilized on the surface of gold nanoparticles/graphene/nafion modified glassy carbon electrode (AuNPs/Gr/Nf/GCE). In the presence of two DNA targets, the hairpin structures of hairpin 1 and hairpin 2 opened through the complementary hybridization, resulting in the formation of hairpin 1: target DNA 1 and hairpin 2: target DNA 2. When they met methylene blue (MB)-labeled hairpin 3 (hairpin 3-MB) and ferrocene (Fc)-labeled hairpin 4 (hairpin 4-Fc), DNA cyclic amplification was activated, and the DNA targets were released and could be reused for the next recycling. Meanwhile, coupled with the utilization of positively charged gold nanoparticles ((+)AuNPs), multiplexed DNA detection was realized in the concentration range from 10 fM to 1.5 pM with the detection limits of 3.6 fM and 2.5 fM for target DNA 1 and target DNA 2, respectively. Moreover, satisfactory results were obtained when detecting DNA targets in human serum samples, suggesting that this proposed sensing platform is promising for the applications in complex biological samples.

中文翻译：

---

表面限制的 DNA 组装能够实现多重电化学 DNA 检测的靶标回收扩增

摘要 设计了一种新型无酶电化学传感器，用于基于表面限制性 DNA 组装的多重 DNA 检测，使目标循环扩增。在这个设计的系统中，两个发夹 DNA 探针（发夹 1 和发夹 2）固定在金纳米粒子/石墨烯/nafion 修饰的玻碳电极（AuNPs/Gr/Nf/GCE）的表面上。在两个DNA靶点存在的情况下，发夹1和发夹2的发夹结构通过互补杂交打开，导致形成发夹1：靶DNA 1和发夹2：靶DNA 2。当它们遇到亚甲蓝（MB）时-标记的发夹 3 (hairpin 3-MB) 和二茂铁 (Fc) - 标记的发夹 4 (hairpin 4-Fc)，DNA 循环扩增被激活，DNA 靶标被释放并可重新用于下一次回收。同时，结合使用带正电荷的金纳米粒子 ((+)AuNPs)，在 10 fM 到 1.5 pM 的浓度范围内实现了多重 DNA 检测，目标 DNA 1 和目标 DNA 2 的检测限分别为 3.6 fM 和 2.5 fM，分别。此外，在检测人血清样本中的 DNA 靶标时获得了令人满意的结果，表明该传感平台有望应用于复杂生物样本。