DNA-templated copper nanoparticles for voltammetric analysis of endonuclease activity

Abstract

DNA endonucleases play critical roles in medicinal chemistry, which are also commonly used in molecular biology investigation. Sensitive quantification of endonuclease activity is of great significance. In this study, a reliable electrochemical approach for endonuclease activity sensing is developed with the adoption of copper nanoparticles (CuNPs) as electrochemical reporters. Firstly, a DNA duplex is designed and modified on a gold electrode, which acts as the template for the synthesis of CuNPs. Subsequently, the formed NPs are dissolved and then electrodeposited on a glassy carbon electrode for DPV measurements. With the effect of target endonuclease, the DNA duplex is specifically recognized and cleaved. Thus, CuNPs cannot be synthesized and a declined DPV peak is obtained to reveal the level of endonuclease activity. This developed sensor has a wide linear range from 10⁻³ to 10 U mL⁻¹, and the limit of detection is 10⁻³ U mL⁻¹, which is extremely low. High stability and excellent reproducibility are also researched. Besides, this sensor shows good selectivity, which can successfully distinguish target endonuclease from possible interferences.