Dual-Mode Sensing Platform for Electrochemiluminescence\nand Colorimetry Detection Based on a Closed Bipolar Electrode

Abstract

Development\nof sensors uniting different sensing principles is\nin line with the concept of reliable, comprehensive, and diversified\nequipment construction. However, the current exploration in this field\nis obstructed by compromise of reaction conditions and inevitable\nmutual interference arising from different sensing modes. This work\nreported a closed bipolar electrode (c-BPE) strategy for dual-modality\ndetection or dual-target detection. To this end, a c-BPE sensing platform\ninstalled in physically separated anode and cathode compartments was\nwell designed and carefully optimized. If luminol was present in the\nanode section and Prussian blue (PB) was at the cathode part, single\nstimulation could realize electrochemiluminescence (ECL) from luminol\nat the anode and conversion of PB to Prussian white (PW) at the cathode.\nThe latter reaction helped elevate the ECL signal and also prepared\nfor colorimetric detection as color change from PW to PB under the\ntrigger of oxidant (like H₂O₂) was used to track\nthe content of the oxidant. Thus, dual signals were obtained for dual-modality\ndetection of single target or the detection of different targets was\nrealized at different poles. Detection of glucose was carried out\nto validate the application for dual-modality detection, while VLDL/AChE\nand NADH/H₂O₂ assays illustrated the potential\nof dual-target detection. The proposed platform possesses outstanding\nsensing performance including selectivity, repeatability, long-term\nstability, accuracy, and so forth. This work implements a breakthrough\nin designing dual-mode sensors and is expected to present a rational\nbasis for development of a diversified sensing platform.