Key Laboratory of Applied Surface and Colloid Chemistry, Key Laboratory of Analytical Chemistry for Life Science of Shaanxi Province, School of Chemistry & Chemical Engineering, Ministry of Education, Shaanxi Normal University, Xi'an 710119, Shaanxi Province, P. R. China.
Anal Chem. 2021 Jan 26;93(3):1620-1626. doi: 10.1021/acs.analchem.0c04073. Epub 2020 Dec 28.
A versatile single magnetic nanoparticle (MNP)-confined, click chemistry-actuated digital DNA walker (ddWalker) machine is devised for the absolute quantification of microRNA (miRNA). This delicate ddWalker allows one target molecule to fix one DNA walking leg on a single MNP, following the Poisson statistics through a specific click chemical DNA ligation, which will initiate single molecule DNA walking to stepwise cleave the molecular beacon tracks strictly constrained on the leg-hold MNP without cross-particle reaction, fluorescently "lighting up" the exact MNP. Accordingly, the initial miRNA input can be digitally and faithfully reflected by the number of fluorescent-positive MNPs counted by a total internal reflection fluorescent microscope, enabling the absolute and precise miRNA quantification down to the femtomolar level without external calibration. This flexible ddWalker design provides a new digital signaling concept and elegantly expands the toolbox for digital biosensing.
设计了一种多功能的单磁纳米颗粒（MNP）限制、点击化学激活的数字 DNA 行走器（ddWalker）机器，用于绝对定量 microRNA（miRNA）。这种精巧的 ddWalker 允许一个靶分子将一个 DNA 行走腿固定在单个 MNP 上，通过特定的点击化学 DNA 连接遵循泊松统计，这将启动单分子 DNA 行走，逐步严格地切割分子信标轨道，该轨道在腿固定 MNP 上受到严格限制，不会发生跨颗粒反应，荧光“点亮”确切的 MNP。因此，通过总内反射荧光显微镜计数荧光阳性的 MNP 数量，可以数字方式和真实地反映初始 miRNA 的输入，实现绝对精确的 miRNA 定量，达到飞摩尔级，无需外部校准。这种灵活的 ddWalker 设计提供了一个新的数字信号概念，并优雅地扩展了数字生物传感工具包。
