Cerium oxide–graphene as the matrix for cholesterol sensor

A simple and sensitive electrogenerated chemiluminescence (ECL) cholesterol biosensor was prepared based on cerium oxide–graphene (CeO2–graphene) composites as an efficient matrix. CeO2–graphene composites were prepared by depositing CeO2 onto graphene and were characterized by scanning electron microscopy. The experimental results demonstrated that CeO2–graphene could catalyze the ECL of a luminol–H2O2 (hydrogen peroxide) system to amplify the luminol ECL signal greatly. In addition, the use of CeO2–graphene provided a better biocompatible microenvironment for the immobilized enzyme, resulting in excellent stability and a long lifetime of the ECL biosensor. The surface assembly process, ECL behaviors, and electrochemistry of the biosensor were investigated in detail. The quantity of cholesterol was in the linear range from 12 μM to 7.2 mM with a detection limit of 4.0 μM (signal/noise = 3). In addition, the biosensor exhibited outstanding reproducibility, long-term stability, and selectivity. Moreover, this cholesterol biosensor offers an alternative analytical method with low cost and high speed.