Logic-Gated Autocatalytic DNA Walker for Dual-miRNA Imaging in Living Cells and Clinical Tissues

DNA-based nanomachines hold great promise for intracellular miRNA sensing and cancer diagnosis. However, conventional approaches often suffer from insufficient sensitivity and specificity, which limits their applicability in clinical diagnostics. Herein, we report an APE1-powered AND-gated DNA walker with autocatalytic amplification (AWA) for the imaging of dual intracellular miRNAs. In this platform, system activation requires the simultaneous presence of miRNA-10b and miRNA-155, which triggers the release of the walking strand. APE1 then drives autonomous walker movement and releases initiators that activate the downstream autocatalytic circuit, resulting in efficient signal amplification. Benefiting from the autocatalytic amplification circuit, the AWA system achieved a low detection limit of 1.62 pM. Moreover, owing to the AND-gated recognition mechanism, the platform accurately discriminated cancer cells based on their distinct miRNA coexpression profiles, and further distinguished cancerous from normal breast tissues in clinical samples. Overall, the AWA system provides a powerful tool for intracellular miRNA analysis and shows significant potential for early cancer diagnosis.