Deformable Smart DNA Nanomachine for Synergistic Intracellular Cancer‐Related miRNAs Imaging and Chemo‐Gene Therapy of Drug‐Resistant Tumors

Diagnosis and treatment of tumor especially drug-resistant tumor remains a huge challenge, which requires intelligent nanomedicines with low toxic side effects and high efficacy. Herein, deformable smart DNA nanomachines are developed for synergistic intracellular cancer-related miRNAs imaging and chemo-gene therapy of drug-resistant tumors. The tetrahedral DNA framework (MA-TDNA) with fluorescence quenched component and five antennas is self-assembled first, and then DOX molecules are loaded on the MA-TDNAs followed by linking MUC1-aptamer and Mcl-1 siRNA to the antennas of MA-TDNA, so that the apt-MA-TDNA@DOX-siRNA (DNA nanomachines) is constructed. The DNA nanomachine can respond to two tumor-related miRNAs in vitro and in vivo, which can undergo intelligent miRNA-triggered opening of the framework, resulting in the "turn on" of the fluorescence for sensitively and specifically sensing intracellular miRNAs. Meanwhile, both miRNA-responded rapid release and pH-responded release of DOX are achieved for chemotherapy of tumor. In addition, the gene therapy of the DNA nanomachines is achieved due to the miRNA-specific capture and the RNase H triggered release of Mcl-1 siRNA. The DNA nanomachines intergrading both tumor imaging and chemo-gene therapy in single nanostructures realized efficient tumor-targeted, image-guided, and microenvironment-responsive tumor diagnosis and treatment, which provides a synergetic antitumor effect on drug-resistant tumor.