Sensitive Imaging of Intracellular Long Noncoding RNAs <i>In Situ</i> in Living Cells Based on Synergistic Dual Hybridization Chain Reaction

Sensitive and specific imaging of long noncoding RNAs (lncRNAs) <i>in situ</i> in living cells is severely challenged by their lengthy sequences and trace amount. Enzyme-free isothermal nucleic acid amplification methods, particularly hybridization chain reactions (HCRs), have been widely applied for intracellular nucleic acid fluorescence imaging. However, HCR methods suffer from a low linear amplification efficiency and prolonged procedure time, limiting their application in rapid diagnostics. In this work, we propose a synergistic dual hybridization chain reaction (SDHCR) strategy, integrating two rounds of HCRs with dual chain displacement actions (CDAs), tailored for ultrasensitive and enzyme-free detection of lncRNA detection. This SDHCR approach markedly enhances both the amplification dynamics and sensitivity compared to conventional HCR techniques. By delivering SDHCR probes into diverse cancer cell lines via manganese dioxide nanoparticles (MnO₂ nanosponges, MNS), we achieved specific and sensitive imaging of a key lncRNA biomarker, ABHD11-AS1. We posit that the advanced amplification strategy holds significant promise as a potent yet user-friendly tool for both fundamental research and clinical diagnostics.