Au/NiFe₂O₄ nanoparticle-decorated graphene oxide nanosheets for electrochemical immunosensing of amyloid beta peptide

Abstract

In the present work, an electrochemical immunosensor has been fabricated for the detection of amyloid beta peptide (βA_1--42) based on a gold nanoparticle/nickel ferrite decorated graphene oxide-chitosan nanocomposite (Au/NiFe₂O₄@GO-Ch) modified glassy carbon electrode (GCE) as an effective sensing platform. βA_1-42 has been analyzed as a potential biomarker for its application in Alzheimer's disease monitoring. The combination of highly conducting Au and NiFe₂O₄ nanoparticles on two-dimensional GO nanosheets provides an excellent platform for sensitive and selective sensing applications. A miniaturized Au/NiFe₂O₄@GO-Ch/GCE immunosensor was prepared by immobilization of βA antibody onto Au//NiFe₂O₄@GO-Ch/GCE <i>via</i> carbodiimide coupling. Various characterization techniques were utilized in the study to estimate the morphological and electronic attributes of the components used to fabricate the immunosensor. Differential pulse voltammetry (DPV) was performed to study the amperometric response of the developed immunosensor as a function of βA_1-42 concentration. The DPV results confirmed that the immunosensor detected βA_1-42 selectively and demonstrated a wide linear range from 1 pg mL^-1 to 1 ng mL^-1 and a detection limit of 3.0 pg mL^-1. Furthermore, the immunosensor also indicated its clinical viability by detecting βA_1-42 in cerebrospinal fluid.