Construction of a Homogeneous Enzyme-Free Autocatalytic Nucleic Acid Machinery for High-Performance Intracellular Imaging of MicroRNA

Compute-and-Release Logic-Gated DNA Cascade Circuit for Accurate Cancer Cell Imaging

“…Next, we verified the cell recognition ability of the CAR-CHA-HCR circuit with MCF-7 (human breast cancer breast cancer cell line) as the targeted cells, which expressed high levels of miR-21 and low levels of miR-892b. ,,,− Figure S17 demonstrates that the red fluorescence in MCF-7 cells was gradually brightened after incubation with CAR-CHA-HCR circuits for 120 min, suggesting an optimized incubation time (120 min) for the following cell testing. In Figure A, a bright red fluorescence was shown in MCF-7 cells, indicating that “ON” fluorescence signals of the CAR-CHA-HCR circuit could be activated in targeted cells as expected.…”

“…To further evaluate the accurate cancer identification of the CAR-CHA-HCR circuit, we selected MCF-7 as positive cells and HEPG2 (human liver cancer cell line) and MCF-10A (normal human renal epithelial cells) as negative cells. MCF-7 cells express high levels of miR-21 while low levels of miR-892b. ,,,− Both miR-21 and miR-892b are overexpressed in HEPG2 cells, but both are expressed lowly in MCF-10A cells. ,,,, For comparison, the conventional fluorescence system based on a single-biomarker-controlled strategy (YES logic gate), miR-21-triggered CHA-HCR circuit, was also tested. Figures S18 and A outline the signal changes of the YES logic gate composed of the CHA-HCR circuit in the three cell lines.…”

“…Considerable effort has been invested in improving the sensitivity of sensing systems, particularly the introduction of various DNA cascade circuit-based isothermal amplification techniques, such as catalytic hairpin assembly (CHA), entropy-driven catalysis (EDC), and hybridization chain reaction (HCR). − These amplification approaches, performing one-to-many signal output, allow a single target molecule to activate many signal molecules by programmed DNA assembly or a DNA chain-growth polymerization reaction, paving a facial path for nonenzymatic signal amplification using only several artificially programmable DNA sequences. Accordingly, extensive research endeavor has been directed toward utilizing DNA cascade circuits to identify cancer-related biomarkers, such as microRNAs, adenosine triphosphate (ATP), and telomerase. − However, the DNA cascade circuits triggered by a single biomarker are prone to unreliable cellular imaging output due to the lack of gating for specific cancer cells.…”

The compact integration of a cascaded HCR circuit for highly reliable cancer cell discrimination

“…To address this issue, effort has been devoted to improve the sensing performance of the HCR circuit, including localized HCR, [30][31][32][33] cascaded HCR [34][35][36][37][38][39] and so on. By conning HCR substrates on DNA scaffolds (e.g.…”

Tailoring a Minimal Self‐Replicate DNA Circuit for Highly Efficient Intracellular Imaging of microRNA

“…First, the efficient amplification depth and multiple guaranteed recognition of self‐stacking CHR circuitry results in the high‐signal‐gain assay and high‐specific recognition, which is especially significant for precisely analyzing and visualizing trace amount of miRNA in biological environment. [ 13 ] Second, the self‐stacking CHR circuitry easily resulted in the elimination of cross‐talk originating from the nonspecific interaction between these heterogeneous circuits, thus leading to the reliable detection and localization of miRNA. [ 14 ] Third, the self‐stacking CHR system in principle generates high‐molecular‐weight branched dsDNA nanostructures with low mobility and high anti‐interference capability, which enables the reliable and precise miRNA‐positioning in complex biological environment.…”