Catalytic probes based on aggregation-induced emission-active Au nanoclusters for visualizing MicroRNA in living cells and in vivo

Highly sensitive monitoring of cancer-related miRNAs is of great significance for tumor diagnosis. Herein, catalytic probes based on DNA-functionalized Au nanoclusters (AuNCs) were prepared in this work. The aggregation-induced emission-active Au nanoclusters showed an interesting phenomenon of aggregation induced emission (AIE) affected by the aggregation state. Leveraging this property, the AIE-active AuNCs were used to develop catalytic turn-on probes for detecting in vivo cancer-related miRNA based on a hybridization chain reaction (HCR). The target miRNA triggered the HCR and induced aggregation of AIE-active AuNCs, leading to a highly luminescent signal. The catalytic approach demonstrated a remarkable selectivity and a low detection limit in comparison to noncatalytic sensing signals. In addition, the excellent delivery the ability of MnO2 carrier made it possible to use the probes for intracellular imaging and in vivo imaging. Effective in situ visualization of miR-21 was achieved not only in living cells but also in tumors in living animals. This approach potentially offers a novel method for obtaining information for tumor diagnosis via highly sensitive cancer-related miRNA imaging in vivo.