Cerium Oxide/Polypyrrole Nanocomposite as the Matrix for Cholesterol Biosensor

Abstract

A nanocomposite comprising cerium oxide nanoparticles (CeO2 NPs) and polypyrrole (PPy) was fabricated onto a microelectrode for cholesterol sensing application. The cholesterol oxidase (ChOx) was immobilized on the CeO2 NPs/PPy/electrode by the physical adsorption route. The structure and morphology of the CeO2 NPs/PPy nanocomposite were characterized by X-ray diffraction, field emission scanning electron microscopy, and energy dispersive X-ray spectroscopy. Results showed that the ChOx/CeO2 NPs/PPy/electrode was linearly related with cholesterol in the range of 50 to 500 mg/dL. The sensitivity of ChOx/CeO2 NPs/PPy/electrode was $5.7\times {10}^{-6}$  mA/mg⋅dL−1. The optimal parameters, including pH value and temperature, and selectivity, storage stability, and reproducibility of ChOx/CeO2 NPs/PPy/electrode were investigated.