Hunan Provincial Key Laboratory of Micro & Nano Materials Interface Science, College of Chemistry and Chemical Engineering, Central South University, Changsha, Hunan, 410083, People's Republic of China.
Henan Province of Key Laboratory of New Optoelectronic Functional Materials, Anyang Normal University, Anyang, Henan, 455000, People's Republic of China.
Mikrochim Acta. 2022 Mar 3;189(3):133. doi: 10.1007/s00604-022-05240-6.
MicroRNAs (miRNAs) play an important role in regulating gene expression in cells. Abnormal expression of miRNAs has been associated with a variety of diseases. A ratiometric electrochemical method for miRNA detection based on DNA nanomachines and strand displacement reaction was developed. Signal probe with ferrocene label and reference probe with methylene blue label were immobilized on gold nanoparticle (AuNP)-coated magnetic microbeads (AuNP-MMBs). The miRNA triggers the strand displacement reaction and forms a duplex with the protect probe, releasing one end of the DNA walker (DW); the released DW hybridizes with the ferrocene (Fc)-labeled signal probe. The signal probe detached from AuNP-MMBs upon cleavage of the Nb.BbvCI enzyme. The oxidation peak of MB moieties on the reference probe remains unchanged and the signals of Fc moieties on the signal probe are inversely proportional to the concentrations of miRNA. The ratio between Fc moieties at 0.35 V and MB moieties at -0.22 V (vs. Ag/AgCl) was used to quantify the expression level of miRNA with a detection limit down to 0.12 fM. The ratiometric assay possesses a strong ability to eliminate interference from environmental changes, thus offering the high selectivity of miRNA from the complexed biosystems, holding great significance for miRNA sensing. A ratiometric assay with high selectivity of miRNA has been developed based on DNA nanomachines and strand displacement reaction.
微小 RNA（miRNA）在细胞基因表达调控中发挥着重要作用。miRNA 的异常表达与多种疾病有关。本文基于 DNA 纳米机器和链置换反应，开发了一种 miRNA 比率型电化学检测方法。用二茂铁标记的信号探针和亚甲蓝标记的参照探针固定在金纳米粒子（AuNP）修饰的磁性微球（AuNP-MMBs）上。miRNA 触发链置换反应，并与保护探针形成双链体，释放 DNA 行走者（DW）的一端；释放的 DW 与二茂铁（Fc）标记的信号探针杂交。Nb.BbvCI 酶切割后，信号探针从 AuNP-MMBs 上脱离。参照探针上 MB 部分的氧化峰保持不变，信号探针上 Fc 部分的信号与 miRNA 的浓度呈反比。在 0.35 V 处 Fc 部分与在-0.22 V（相对于 Ag/AgCl）处 MB 部分的比值用于定量 miRNA 的表达水平，检测限低至 0.12 fM。该比率测定法具有较强的消除环境变化干扰的能力，从而从复杂的生物体系中提供 miRNA 的高选择性，对 miRNA 传感具有重要意义。基于 DNA 纳米机器和链置换反应，开发了一种具有高选择性的 miRNA 比率型测定法。
