Enzymatically triggered DNA nanodevices for dynamic monitoring of epithelial-mesenchymal transition via duplexed miRNA imaging

Despite microRNAs (miRNAs) are key regulators of epithelial-mesenchymal transition (EMT), approaches allowing for real-time monitoring of EMT process of tumor cells via miRNA imaging have yet to be achieved. Herein we present the design of an enzyme-controlled DNA nanodevice for activatable parallel imaging of two independent target miRNAs, thus achieving cancer cell-specific monitoring of EMT process. Toehold-mediated strand displacement reactions and enzyme activatable modules are integrated in the DNA nanodevice design to achieve generation of multiple signal outputs in response to different miRNA inputs. The system allows for enzymatically activatable two-input and three-output imaging patterns in cancer cells, while possesses no miRNA sensing functions in normal cells, resulting in an enhanced sensitivity and cell specificity for the cancer-selective monitoring of EMT dynamics. Furthermore, it is demonstrated that the DNA nanodevice can rapidly discriminate EMT state of chemoresistant carcinoma cells by duplexed miRNA imaging in an enzyme-activated manner. We envision the application of this multiplexed imaging technology for decoding the roles of EMT in diverse pathological processes.