▎ 摘　　要

NOVELTY - Visual sensor based on nucleic acid self-assembly and enzymatic-free circular RNA (circRNA) live cell imaging comprising (i) high-efficiency intracellular delivery system based on graphene oxide (GO), and (ii) GO-based signal switch system, (iii) enzyme-free catalytic nucleic acid self-assembly dual signal amplification imaging system based on the combination of catalyzed hairpin assembly (CHA) and hybridization chain reaction (HCR), the visual sensor realizes that the detection of the sample to be tested needs to sequentially go through the GO to the CHA and HCR detection hairpin chain enrichment and delivery into the cell, in the presence of the target circRNA, triggering the double-signal amplification imaging system of non-enzyme-catalyzed nucleic acid self-assembly combined by CHA and HCR, and releasing the fluorophore quenched by GO to achieve dual signal output. USE - The sensor is useful for detecting circular RNA (claimed). ADVANTAGE - The sensor uses biocompatibility and fluorescence quenching effect of GO to complete the detection of target circRNA in living cells, solves cumbersome detection process of circRNA by traditional polymerase chain reaction (PCR), sequencing, north blot and other detection methods, is difficult to sensitively visualize the problem, realizes rapid, high-sensitivity and high-selectivity visual detection of circRNA in living cells, and is more accurate, real-time and efficient in circRNA detection as biomarker. DETAILED DESCRIPTION - Visual sensor based on nucleic acid self-assembly and enzymatic-free circular RNA (circRNA) live cell imaging comprising (i) high-efficiency intracellular delivery system based on graphene oxide (GO), and (ii) GO-based signal switch system, (iii) enzyme-free catalytic nucleic acid self-assembly dual signal amplification imaging system based on the combination of catalyzed hairpin assembly (CHA) and hybridization chain reaction (HCR), the visual sensor realizes that the detection of the sample to be tested needs to sequentially go through the GO to the CHA and HCR detection hairpin chain enrichment and delivery into the cell, in the presence of the target circRNA, triggering the double-signal amplification imaging system of non-enzyme-catalyzed nucleic acid self-assembly combined by CHA and HCR, releasing the fluorophore quenched by GO to achieve dual signal output, where the CHA and HCR combined enzyme-free catalyzed nucleic acid self-assembly dual signal amplification imaging system comprises CHA and HCR detection hairpin strands hairpin probe (HP1), HP2, H1, H2 and circRNA replacement strands I' and I to be detected, the HP 1 comprises fully defined sequence of 64 nucleotides (SEQ ID NO: 1) as given in the specification, HP2 comprises fully defined sequence of 72 nucleotides (SEQ ID NO: 2) as given in the specification, H1 comprises fully defined sequence of 33 nucleotides (SEQ ID NO: 3) as given in the specification, H2 comprises fully defined sequence of 44 nucleotides (SEQ ID NO: 4) as given in the specification, I' comprises sequence represented by 5'-acggccuaccucaagacgaaac-3' (SEQ ID NO: 5), I comprises sequence represented by 5'-acggcctacctcaagacgaaac-3' (SEQ ID NO: 6), where the 3' end of (SEQ ID NO: 1) and 5'end of (SEQ ID NO: 2) is added with carboxyfluorescein (FAM) groups, respectively. INDEPENDENT CLAIMS are also included for: (1) qualitatively detecting circRNA using the sensor, comprising (S1) combining CHA and HCR hairpin chain in CHA and HCR reaction buffer, (S2) adding the circRNA mixture to be detected into the detection system and using fluorescence spectrophotometer to detect the fluorescence intensity, and (S3) adding the detection system into the cells for incubation, and observing the changes in the intracellular fluorescence using fluorescence microscope; and (2) quantitatively detecting circRNA using the sensor, comprising (SI) using the circRNA splicing sequence solution of known concentration to construct detection system with different circRNA splicing sequence concentrations, drawing standard curve with the concentration of circRNA splicing sequence as the abscissa and fluorescence intensity as the ordinate, and (SII) detecting the sample to be tested, substituting the measured fluorescence intensity value into the standard curve, calculating the content of circRNA in the sample to be tested, and realizing the quantitative detection of circRNA.