Electrochemical fabrication of Ru[bpy]32+@Cu-MOF(-SH)/Au photo/electrochemical coupling interface and its DNA-based biosensing performance

Abstract

An electrochemical fabrication method of Ru[bpy]32+@Cu-MOF(-SH)/Au (MOF = metal–organic framework) was developed with a photo/electrochemical information characterization and a DNA-based biosensing validation for the proposed interface. Applying an anodic synthesis method, a modification layer of Ru[bpy]32+ encapsulated with MOF was formed on the Au electrode surface to fabricate an interface with photo/electrochemical dual-signal response. Combining the scanning electrochemical microscopy (SECM) imaging technology with electrochemical and electrochemiluminescence (ECL) detection, the information about the interfacial photo/electrochemical bi-functional properties was explored from three aspects of the parameter variable, intensity variable, and morphology variable. The results show that the effect of parameter variables on the interfacial response follows an “interference effect” mechanism. Under the optimized conditions, the background and the saturation ECL intensities are 610.0 and 24.0 with a quenching efficiency of 96.1% and a detection limit of 30 fM. The saturation current is 48.8 µA with a detection limit of 330.0 nM. Both ECL and electrochemical imaging methods can corroborate each other, validating the logical correlation between the interface fabrication and the response performance in the regional interfacial distribution and laying a methodological foundation for evaluating the interface fabrication quality based on imaging morphology qualitatively. The proposed interface can construct photo/electrochemical dual-signal DNA-based biosensors.