▎ 摘　　要

In the present work, an electrochemical immunosensor has been fabricated for the detection of amyloid beta peptide (beta A(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. beta A(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 beta A antibody onto Au//NiFe2O4@GO-Ch/GCE via 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 beta A(1-42) concentration. The DPV results confirmed that the immunosensor detected beta A(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 beta A(1-42) in cerebrospinal fluid.