A cathodic luminol-based electrochemiluminescence biosensor for detecting cholesterol using 3D-MoS2–PANI nanoflowers and Ag nanocubes for signal enhancement

Abstract

A sensitive cathodic luminol-based electrochemiluminescence (ECL) biosensor for detecting cholesterol was fabricated with three-dimensional MoS₂–polyaniline (3D-MoS₂–PANI) nanoflowers and Ag nanocubes (AgNCs) for signal enhancement. In this study, the synthesized 3D-MoS₂–PANI–AgNCs nanocomposites with a large surface area were used as a matrix for loading a high amount of cholesterol oxidase (ChOx). Subsequently, the loaded ChOx efficiently catalyzed the oxidation of cholesterol to produce H₂O₂ in situ, which could promote the oxidation of luminol to generate a cathodic ECL signal. In addition, 3D-MoS₂–PANI–AgNCs nanocomposites accelerate the decomposition of H₂O₂ into reactive oxygen species (ROSs), which increase the ECL intensity. Due to the integration of the properties of 3D-MoS₂–PANI nanoflowers and AgNCs, the proposed cholesterol biosensor exhibits a wide linear response range from 3.3 nM to 0.45 mM with a low detection limit of 1.1 nM.