Synergistic signal amplification via DNAzyme-driven DNA walker and MnAu nanozyme for sensitive electrochemical detection of CA15-3

DNAzyme-driven DNA walker combined with bimetallic nanozyme for synergistic signal amplification in an electrochemical biosensor. • Enzyme-free and Zn 2+ -dependent operation, which simplifies the assay workflow and enhances robustness. • Quantitative release of nanozymes triggered by target-induced DNA cleavage, enabling highly sensitive and specific detection. Early and accurate detection of breast cancer is essential for improving patient prognosis. Carbohydrate antigen 15-3 (CA15-3) is a key serum biomarker used in clinical monitoring, yet its low abundance in early stages requires highly sensitive detection methods. Herein, we report an electrochemical biosensor that synergistically integrates a DNAzyme-driven DNA walker with bimetallic MnAu nanozymes for CA15-3 detection. Target recognition activates the DNAzyme walker, which progressively cleaves substrate strands and releases MnAuNP signal probes from the electrode surface. This process attenuates the nanozyme-catalyzed electrochemical signal for quantitative analysis. The core-shell MnAuNP provides robust oxidase-like activity, while the DNA walker enables efficient enzyme-free signal amplification. This synergistic amplification strategy achieves a wide linear range (0.05 U/mL–200 U/mL) and a low limit of detection (LOD) of 0.0017 U/mL with excellent selectivity. Satisfactory recovery rates (97.58–105.35%) in human serum confirm clinical potential. This work presents a novel strategy for breast cancer biomarker detection by combining DNA walker with nanozyme catalysis amplification, demonstrating promising potential for point-of-care breast cancer diagnostics. Download: Download high-res image (133KB) Download: Download full-size image