An electrochemical sensor based on DNA triangular prism and HCR for ultra-sensitive detection of microRNA

MicroRNAs (miRNAs) are closely associated with the development and progression of cancer, making the development of highly sensitive and rapid miRNA detection strategies a significant challenge. Herein, we developed an electrochemical sensor based on DNA triangular prism (TP) and hybridization chain reaction (HCR) for the ultra-sensitive, rapid, and specific analysis of miRNA. The TP was modified on the electrode surface to obtain high density of recognition probes. After hybridization of the target miRNA with the recognition probes on the TP, HCR was further activated. Numerous biotin-carrying HCR products were generated on the electrode surface. Then the biotin on the HCR products efficiently bound to streptavidin-horseradish peroxidase (SA-HRP), and under the catalysis of a large amount of HRP, TMB and H 2 O 2 rapidly underwent redox reactions, producing the enhanced electrical signal, thus achieving high-sensitivity analysis of miRNA. The developed strategy has a detection limit of 2.21 aM and demonstrates high specificity with the ability to distinguish single-base-pair differences in miRNA. The strategy also exhibits good reproducibility, stability, and practical application potential. We believe that this developed strategy holds promise as an effective tool for miRNA analysis and is expected to play a crucial role in disease diagnosis and new drug development.