Janus wireframe DNA cube-based 3D nanomachine for rapid and stable fluorescence detection of exosomal microRNA.

Exosomal microRNAs (miRNAs) have been demonstrated to be credible biomarkers for the diagnosis and monitoring of tumors. Nevertheless, developing simple, rapid, and stable biosensing strategies that are capable of accurately detecting exosomal miRNAs remains a challenge. Herein, an accelerated and biostable three-dimensional (3D) nanomachine based on Janus wireframe DNA cube was constructed for sensitive fluorescence measurement of exosomal miRNA. The Janus wireframe DNA cube could propel target exosomal miRNA-21 rapid movement on its surface by catalytic hairpin assembly (CHA), releasing a massive fluorescence signal. Benefiting from the Janus wireframe DNA cube, the developed 3D nanomachine exhibited significantly improved reaction rate and enhanced biostability in complex biofluids compared to conventional CHA. As a result, this fluorescence biosensing strategy achieved rapid, stable, and single-step detection of exosomal miRNA-21 with the detection limit down to the picomole level. Therefore, this work offers a brief sensing tool for nucleic acid biomarkers detection, which has great application potential in tumor diagnosis.