Detección sensible de microARN mediante electroquímica de colisión de nanopartículas únicas utilizando nanopartículas...

MicroRNA (miRNA) quantification is pivotal for disease diagnostics and molecular mechanism studies, yet existing methods often suffer from limited sensitivity or complex workflows. Herein, we present a novel electrochemical sensor for miRNA-21 detection based on AgNP collision-oxidation and DSN-mediated signal amplification. The AgNPs are functionalized with target-specific ssDNA probes, which initially block electrode contact ("off" state). Upon miRNA-21 hybridization, DSN cleaves the duplex to expose AgNPs, enabling oxidation-induced current transient ("on" state) with signal frequency positively correlated with target miRNA concentration. The sensor achieved a limit of detection (LOD) of 0.011 fM and a linear detection range of 0.05 fM to 1000 fM, along with excellent specificity that enables effective distinction between the target miRNA and mismatched or non-complementary miRNA analogs. The sensor successfully detected miRNA-21 in spiked human serum (recovery: 96.7-112 %), demonstrating its promising clinical potential for liquid biopsy applications. Our work provides a simple yet powerful tool for low-abundance miRNA analysis in complex biological samples.