Intracellular CircRNA imaging and signal amplification strategy based on the graphene oxide-DNA system

• Published in: Analytica chimica acta 2021-10, Vol.1183, p.338966-338966, Article 338966
• Main Authors: Li, Hongyu, Zhang, Boyang, He, Xiaoyun, Zhu, Longjiao, Zhu, Liye, Yang, Min, Huang, Kunlun, Luo, Haoshu, Xu, Wentao
• Format: Article
• Language: English
• Subjects: CircRNA; Enzyme-free; GO nanosheets; GO-CHA-HCR (GO-AR); Intracellular imaging; Two-stage signal amplification
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/j.aca.2021.338966

CircRNA is a type of covalently closed circular RNA molecule that serves as a potential biomarker for the disease early diagnosis and clinical researches. To achieve living cell imaging of specific circRNA, we developed a novel graphene oxide (GO)-based catalytic hairpin assembly (CHA) and hybridization chain reaction (HCR) signal dual amplification system (GO-CHA-HCR, abbreviated GO-AR) for circ-Foxo3 imaging in living cells. The developed system consists of four types of designed hairpin DNA HP1, HP2, H1, and fluorophore-labeled H2, which are absorbed on the GO nanosheets surface leading to fluorescence quenching. In the presence of circ-Foxo3, the CHA cycle was initiated to form a hybrid chain with split fragments, which triggered the HCR cycle to generate dsDNA nanowires that were then released from GO. This process recovered the quenched fluorescence, realizing two-stage signal amplification. The GO-AR system effectively improved the signal-to-noise ratio compared to the traditional GO-CHA and GO-HCR detection system. The detection limit of circ-Foxo3 was as low as 15 pM with excellent sensitivity and selectivity. In addition, the enzyme-free sensing system was successfully applied in living cell circRNA imaging and serum circRNA detection, indicating its high potential in clinical diagnostics. [Display omitted] •Living cell imaging of circRNA firstly developed through signal amplification.•Specific circRNA instantaneous quantitative imaging in living cell was achieved.•GO-AR system has excellent stability, even detecting circ-Foxo3 in serum.•The detection probe can be successfully assembled within 15min, easy to operate.•GO realized the conversion of FAM signal through FRET to regulate signal output.