All-In-One Entropy-Driven DNA Nanomachine for Tumor Cell-Selective Fluorescence/SERS Dual-Mode Imaging of MicroRNA.

An entropy-driven catalysis (EDC) strategy is appealing for amplified bioimaging of microRNAs in living cells; yet, complex operation procedures, lacking of cell selectivity, and insufficient accuracy hamper its further applications. Here, we introduce an ingenious all-in-one entropy-driven DNA nanomachine (termed as AIO-EDN), which can be triggered by endogenous apurinic/apyrimidinic endonuclease 1 (APE1) to achieve tumor cell-selective dual-mode imaging of microRNA. Compared with the traditional EDC strategy, the integrated design of AIO-EDN achieves autocatalytic signal amplification without extra fuel strands. Moreover, the AIO-EDN leverages an endogenous APE1 overexpressed in cancer cells to activate the EDC reaction, which, however, exerts no target sensing activity in normal cells. Combining fluorescence- and surface-enhanced Raman scattering (FL/SERS) dual-mode imaging techniques, this DNA nanomachine exhibits significantly improved accuracy and tumor cell selectivity for microRNA imaging in living cells. This study provides a new paradigm to develop an integrated EDC-based platform and shows great potential in in-depth cancer diagnosis with high precision.