Dual-endogenous activation and self-reinforcing DNA nanodevice for highly efficient and specific imaging of MicroRNA in living cells

Tumor-specific microRNA (miRNA) imaging strategies are essential for studying mechanisms involved in cancer progression. However, their selectivity and detection effectiveness are often limited by nonspecific signal leakage and false-positive signals. In this study, a dual-endogenous activation and self-reinforcing target nucleic acid probing (DTNP) system were designed for spatially specific and high-contrast miRNA imaging in living cells. This DTNP system employs a hybridization chain reaction (HCR) and incorporates DNA components with intelligent response and self-driving functions, including redox activation, mRNA activation, and autocatalytic miRNA detection capabilities. The HCR mechanism enables the DTNP system to achieve highly sensitive target detection. Initially, the system remained inactive and being selectively activated by tumor-associated endogenous microenvironmental factor glutathione (GSH), which is overexpressed in tumor cells. Subsequently, an additional tumor-specific endogenous biomarker, TK1-mRNA, was employed to further suppress nonspecific signal leakage, particularly preventing false-positive signals in extracellular environments. Finally, the system forms an autocatalytic DNA circuit (HCR) to facilitate tumor-specific, high-contrast miRNA imaging. The DTNP system effectively integrates the triple tumor biomarker-based response mechanism (GSH activation, TK1-mRNA activation, and miRNA autocatalytic detection), which can significantly improve cellular discrimination and the precision of cancer diagnosis. The innovative DTNP system shows immense potential for precise biomedical imaging and clinical diagnostic applications.