Bipolar Electrode Based Multicolor Electrochemiluminescence\nBiosensor

Abstract

We report a multicolor\nECL device based on closed bipolar electrode\n(BPE) for the visualized sensing of prostate-specific antigen (PSA)\nin human blood serum. As the emission color of concomitant electrochemiluminophores\nis potential resolved, similar to a three-electrode system, selective\nexcitation of ECL could be achieved by tuning the interfacial potential\nat the poles of BPE. Via modulating the resistance of BPE, multicolor\nECL emission of [Ru­(bpy)₃]²⁺ and [Ir­(ppy)₃] mixture using tripropylamine (TPrA) as the co-reactant was\nobserved at the anode and the principle was elaborated. The concept\nwas utilized to the quantification of clinical biomarkers with the\ncolor variation. A PSA concentration dependent silver bridge was constructed\nin the gap of the BPEs as an electric conductivity modulator. On the\nbasis of a multicolor BPE-ECL device, the cutoff values (4.0 and 10.0\nng/mL) of human PSA could be recognized with naked eyes by the green–yellow–red\nECL emission changing. As the first multicolor ECL device in biological\nanalysis, BPE may raise the application of potential-resolved ECL\nto a new level.