Construction of a Self-Assembled DNA Nanofirework for Signal Amplification and Intracellular miRNA Imaging

Nonenzymatic DNA catalytic amplification strategies have greatly improved the detection of biomolecules. However, the membrane barrier and the complex intracellular environment remain the two main challenges for efficient intracellular RNA imaging. Herein, we designed a self-assembled DNA nanofirework for amplified microRNA (miRNA) imaging in living cells. The self-assembled DNA nanofireworks exhibited high sensitivity and specificity for miRNA detection, achieving excellent internalization efficiency through endocytosis, while demonstrating enhanced biostability and biocompatibility. These properties enable powerful signal-amplified miRNA imaging in live cells. Under optimized conditions, this nanoprobe achieves a linear detection range of 0.5-8.0 nM for miRNA-21 with a detection limit of 89.3 pM. This design represents an optimal integration of DNA nanotechnology with nucleic acid amplification for intracellular biomolecule analysis, providing valuable insights for understanding the biological functions of important biomolecules in disease pathogenesis and potential therapeutic applications.