Highly sensitive detection of miRNA-21 based on hybridization chain reaction and atom transfer radical polymerization.

BACKGROUND

Early cancer diagnosis is crucial for improving therapeutic outcomes and survival rates. Research in molecular oncology has shown that tumor-associated biomarkers, particularly miRNAs, are promising key indicators for early detection. However, traditional miRNA detection methods are hindered by complex procedures, insufficient sensitivity, and high costs, limiting their clinical application. Thus, there is an urgent need to develop sensitive, simple, and cost-effective detection platforms.

RESULTS

This study introduces a novel biosensing platform combining Hybridization Chain Reaction (HCR) and Atom Transfer Radical Polymerization (ATRP) for ultrasensitive electrochemical detection of miRNA-21. HCR-driven DNA probe hybridization facilitates target miRNA recognition, while ATRP-mediated signal amplification further enhances the electrochemical response. The HCR mechanism generates multiple initiator anchoring sites via programmable DNA self-assembly, enabling covalent immobilization of ATRP initiators (α-bromophenylacetic acid, BPAA). The ATRP process facilitates the growth of electroactive polymers on the electrode surface, significantly enhancing signal stability and sensitivity. The biosensor exhibits exceptional sensitivity for miRNA-21 detection, with a linear range from 100 pM to 10 aM and a low detection limit of 4.96 aM, outperforming most existing electrochemical methods. Furthermore, the sensor demonstrates strong anti-interference in serum analysis, with a recovery rate of 98.48 %-105.22 %.

SIGNIFICANCE: The HCR-ATRP dual signal amplification strategy offers a robust, cost-effective, and scalable solution for early cancer screening. Its performance in miRNA-21 detection demonstrates exceptional sensitivity, strong anti-interference, excellent stability, and ease of use. This not only highlights its superior detection capability but also underscores the platform's broad potential in identifying other cancer-related biomarkers.