Signal-enhanced electrochemical immunosensor for CD36 based on cascade catalysis of a GOx labeled Prussian blue functionalized Ceria nanohybrid

Abstract

Human scavenger receptor B type CD36 (CD36), a member of the class B scavenger receptors, has been shown to play a critical role in the formation of atherosclerosis and may be a potential target for the treatment of atherosclerosis. Sensitive and accurate determination of CD36 is strongly desired in clinical testing in recent years. On the basis of the improved sensitivity of electrochemical immunoassays, a novel electrochemical immunosensor was constructed for CD36 with glucose oxidase (GOx) labeled Prussian blue nanoparticle functionalized Ceria nanoparticles (PB@CeO₂NPs) as the signal enhancer. The prepared nanohybrid of PB@CeO₂NPs exhibits excellent electrochemical catalytic activity like “artificial peroxidase”, with the cooperative catalysis of Prussian blue nanoparticles (PBNPs) and Ceria nanoparticles (CeO₂NPs) for the effective reduction of H₂O₂, as well as strong and stable quasi-reversible cyclic voltammetry curves due to the important roles of PBNPs with their intrinsic redox electrochemical properties. Significantly, the electrochemical signal was greatly enhanced due to cascade catalysis: firstly, GOx catalyzed the deoxidization of glucose to gluconic acid with the concomitant generation of H₂O₂; then H₂O₂ was further decomposed by the catalysis of the “artificial peroxidase” of PBNPs and CeO₂NPs. Thus, this proposed method was developed for the determination of CD36, based on sandwich-type immunoreactions, and it exhibited good electrochemical responses at a linear calibration range from 5.0 × 10⁻³ ng mL⁻¹ to 80 ng mL⁻¹, with a detection limit of 2.0 pg mL⁻¹.