The development of a nanographite (NG)-based fluorescent biosensor for detecting microRNA (miRNA) is reported. Duplex-specific nuclease (DSN)-assisted signal amplification was key to its function. In the absence of a target, with the assistance of p-stacking interactions, the NG adsorbed the double carboxyfluorescein (FAM)-labelled probe (DFP) whose surface was perfectly complementary to miRNA, leading to quenching of FAM fluorescence. In the presence of a target, double-stranded DNA/RNA hybrids were repelled by the NG and fluorescence was restored. Meanwhile, the considerable increase in signal strength and sensitivity suggests DSN-mediated target recycling as an application. The detection limit of the proposed biosensor for miRNA was 10 pmol/L; there was a linear correlation when the miRNA concentration ranged from 50 pmol/L to 5 nmol/L. Additionally, the method could distinguish let-7b from most let-7 miRNA family members and was successfully used in a sample assay. This biosensor is a novel and highly sensitive tool for miRNA detection and has great potential for biochemical research, disease diagnosis, and therapy.

中文翻译：

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基于纳米石墨的荧光生物传感器，用于使用双特异性特异性核酸酶辅助回收检测microRNA。

据报道，用于检测微小RNA（miRNA）的基于纳米石墨（NG）的荧光生物传感器的发展。双链特异性核酸酶（DSN）辅助信号放大是其功能的关键。在没有靶标的情况下，借助p堆积相互作用，NG吸附了表面与miRNA完全互补的双羧基荧光素（FAM）标记的探针（DFP），导致FAM荧光淬灭。在存在靶标的情况下，NG排斥双链DNA / RNA杂种，并恢复了荧光。同时，信号强度和灵敏度的显着提高表明DSN介导的靶标回收是一种应用。拟议的miRNA生物传感器的检出限为10 pmol / L；当miRNA浓度在50 pmol / L至5 nmol / L之间时，存在线性相关。另外，该方法可以将let-7b与大多数let-7 miRNA家族成员区分开，并成功用于样品测定中。这种生物传感器是用于miRNA检测的新型且高度灵敏的工具，在生化研究，疾病诊断和治疗方面具有巨大潜力。