Nanotechnology

In vivo

Biology

Gene

Biophysics

Catalysis

microRNA

Chemistry

Materials science

Computational biology

Preclinical imaging

Autocatalysis

Genetics

Biochemistry

Deoxyribozyme

Angewandte Chemie International Edition

DNAzymes have been recognized as promising transducing agents for visualizing endogenous biomarkers, but their inefficient intracellular delivery and limited amplification capacity (including insufficient cofactor supply) preclude their extensive biological application. Herein, an autocatalytic DNAzyme (ACD) biocircuit is constructed for amplified microRNA imaging in vivo based on a hybridization chain reaction (HCR) and DNAzyme biocatalysis, sustained by a honeycomb MnO 2 nanosponge (hMNS). The hMNS not only delivers DNA probes, but also supplies Mn 2+ as a DNAzyme cofactor and magnetic resonance imaging (MRI) agent. Through the subsequent cross‐activation of HCR and DNAzyme amplicons, the ACD amplifies the limited signal resulting from miRNA recognition. The hMNS/ACD system was used to image microRNA in vivo, thus demonstrating its great promise in cancer diagnosis.

A Smart, Autocatalytic, DNAzyme Biocircuit for in Vivo, Amplified, MicroRNA Imaging