DNAzyme-driven electrochemical detection of copper ions using signal-amplifying two-dimensional Zr-MOFs

Ultrasensitive detection of copper ions (Cu 2+ ) is essential for clinical diagnostics and environmental monitoring. This study introduces a novel electrochemical detector for ultrasensitive Cu 2+ detection, utilizing two-dimensional zirconium-based metal-organic frameworks (2D Zr-MOFs) as electrochemical signal amplifiers integrated with a Cu 2+ -specific DNAzyme for target recognition. The unique 2D morphology of the Zr-MOFs provides abundant exposed active sites, enabling a strong and stable electrochemical response. The detection mechanism is based on the Cu 2+ -induced DNAzyme cleavage, which initiates significant electrochemical signal amplification by the 2D Zr-MOFs. The fabricated biosensor achieves an exceptional detection limit of 1.12 × 10 −12  M and a broad linear range from 10 −11 to 10 −4  M, with excellent selectivity and reproducibility. Furthermore, the developed biosensor performed reliably in real water samples, demonstrating its practical applicability. This work not only presents a superior platform for Cu 2+ detection but also pioneers a general strategy that combines the electrochemical signal-enhancing properties of MOFs with the recognition specificity of DNAzymes, paving the way for the next generation of high-performance electrochemical sensors.