Near-Infrared Light-Activated DNA Biosensor for Sensitive Detection of miRNAs via a Catalytic Hairpin Assembly Signal Amplification Strategy

Maintenance hemodialysis (MHD) is currently one of the treatments for uremia, but vascular calcification is the most common complication in MHD patients. Research has shown that peripheral blood microRNA-21 is abnormally expressed in uremic patients with vascular calcification. Therefore, it is necessary to detect miRNAs with sensitivity and specificity for early screening of uremia patients with vascular calcification complications. In this work, a light-activated DNA biosensor was constructed by using a catalytic hairpin assembly (CHA) signal amplification strategy and upconversion nanoparticles (UCNPs) for sensitive and specific determination of miRNA-21. A light-activated DNA hairpin (H1) was modified on the superficial layer of the UCNPs to trigger the analyte miRNA. In the presence of both NIR light and miRNA, H1 can hybridize with another DNA hairpin (H2) labeled with BHQ-2 and Cy5 at its two terminals, enabling fluorescence from "OFF" to "ON". Furthermore, the released analyte miRNA triggers catalytic assembly, establishing an NIR-activated CHA amplification system. The constructed biosensor was used to detect miRNA-21, with a low detection limit (LOD) of 0.25 nM. Additionally, this biosensor can detect miRNA-21 in serum samples, with recoveries ranging from 96.7%-102.0%, suggesting that the current work provides an opportunity to develop NIR-activated signal amplification platforms for sensitive miRNA detection in biological samples.