Long non-coding RNA (LncRNA) as an emerging tumor biomarker plays a key factor in the early diagnosis of cancer. Herein, an innovative signal-switchable photoelectrochemical (PEC) biosensor based on ZrO@CuO bimetallic oxides and T7 Exo-assisted signal amplification is reported for the ultrasensitive and selective detection of lncRNA (HOX gene antisense intergenic RNA, HOTAIR) in cancer cells. Firstly, MOFs-derived TiO nanodisks as an excellent photoactive material show an anodic background signal. When target lncRNA exists, the abundant auxiliary DNA1 is freed from T7 Exo-assisted cycle signal amplification, and then competitively hybridizes with auxiliary DNA2 on the electrode. Subsequently, bimetallic MOFs-derived ZrO@CuO octahedra with a high specific surface area and porous structure are introduced into TiO nanodisks-modified biosensor, which appears a cathodic photocurrent and achieves a switchable signal. The developed signal-switchable PEC biosensor shows ultrasensitive detection of lncRNA HOTAIR with a detection limit of 0.12 fM, and can eliminate the false interference. Importantly, the established PEC biosensor has good correlation with RT-qPCR analysis (P < 0.05) for the quantification of lncRNA HOTAIR in cancer cells, which has great potential application for biomarker detection in the early diagnosis of cancer.

中文翻译：

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一种信号可切换光电化学生物传感器，用于超灵敏检测癌细胞中的长非编码RNA

长链非编码RNA（LncRNA）作为一种新兴的肿瘤生物标志物在癌症的早期诊断中发挥着关键作用。在此，报道了一种基于ZrO@CuO双金属氧化物和T7 Exo辅助信号放大的创新信号可切换光电化学（PEC）生物传感器，用于超灵敏和选择性检测癌细胞中的lncRNA（HOX基因反义基因间RNA，HOTAIR）。首先，MOFs 衍生的 TiO 纳米盘作为一种优异的光活性材料显示出阳极背景信号。当目标lncRNA存在时，丰富的辅助DNA1从T7 Exo辅助循环信号放大中释放出来，然后与电极上的辅助DNA2竞争性杂交。随后，将具有高比表面积和多孔结构的双金属MOFs衍生的ZrO@CuO八面体引入TiO纳米盘修饰的生物传感器中，出现阴极光电流并实现可切换信号。开发的信号可切换PEC生物传感器对lncRNA HOTAIR具有超灵敏的检测能力，检测限为0.12 fM，并且可以消除虚假干扰。重要的是，所建立的PEC生物传感器与癌细胞中lncRNA HOTAIR定量的RT-qPCR分析具有良好的相关性（P < 0.05），这在癌症早期诊断中的生物标志物检测中具有巨大的潜在应用。