Here we report a sensing scheme for detection of microRNA (miRNA) using electrocatalytic amplification (ECA). ECA is a method in which nanoparticles (NPs) that are catalytic for a specific electrochemical reaction collide with an inert electrode surface. Each collision results in a detectable current transient. In the present article, we show that this general approach can be extended to detection of miRNA. Specifically, PtNPs are modified with a single-strand DNA (ssDNA) shell that is complementary to the miRNA target. Next, the ssDNA:miRNA conjugate is formed, which passivates the PtNP surface. In the presence of an enzyme called duplex specific nuclease (DSN), however, a fraction of the surface-bound DNA is removed thereby exposing some of the PtNP surface. In other words, the electrocatalytic properties of the PtNPs are reactivated only if miRNA complementary to ssDNA is present. This methodology resolves a number of problems that have rendered ECA ineffective for biosensing applications. Moreover, the results suggest that the underlying chemistry is broadly applicable to nucleic acid sensing.

中文翻译：

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通过电催化扩增检测 microRNA：单粒子生物传感的一般方法

在这里，我们报告了一种使用电催化放大 (ECA) 检测 microRNA (miRNA) 的传感方案。ECA 是一种对特定电化学反应具有催化作用的纳米粒子 (NP) 与惰性电极表面碰撞的方法。每次碰撞都会导致可检测的电流瞬变。在本文中，我们展示了这种通用方法可以扩展到 miRNA 的检测。具体来说，PtNPs 是用与 miRNA 靶标互补的单链 DNA (ssDNA) 外壳修饰的。接下来，形成 ssDNA:miRNA 偶联物，钝化 PtNP 表面。然而，在称为双链特异性核酸酶 (DSN) 的酶的存在下，一部分表面结合的 DNA 被去除，从而暴露出一些 PtNP 表面。换句话说，只有当存在与 ssDNA 互补的 miRNA 时，PtNPs 的电催化特性才会重新激活。这种方法解决了许多使 ECA 对生物传感应用无效的问题。此外，结果表明基础化学广泛适用于核酸传感。