Unique Optical Properties of DNA/Ru(II)Complex and Their Electrochemical Application

Abstract

DNA has ability to incorporate various functional materials and to form highly ordered structure of DNA/functional materials, so to speak, “DNA softcrystal”. We aim to fabricate DNA-based functional complex by associating DNA and ruthenium (Ru(II)) complexes. In this review, we introduce unique optical properties of DNA/Ru(II) complex and their application for electrochemical devices. Among various functionality of Ru(II) complexes, we are focusing on electrochemiluminescence (ECL). Electrochemical and ECL properties of DNA/Ru(bpy)₃²⁺ hybrid film on ITO electrodes were investigated. The hybrid film fabricated by electrophoretic migration contained unique micrometre-scale aggregates of Ru(bpy)₃²⁺ in DNA matrix. The Ru(bpy)₃²⁺ in the DNA/Ru(bpy)₃²⁺ hybrid film exhibited significant electrochemical reactivity. As a result, orange-coloured ECL was observed from only the aggregated structures in the hybrid film at the high AC frequency of 10kHz, which corresponds to a response time shorter than 100μs.