Abstract

Conducting PAni/Fe3O4 nanocomposites were synthesized and electrochemically deposited on FTO coated glass to form a transducing layer owing to their catalytic, magnetic and electrical properties. This synthesized conducting layer was used to immobilized anti-β42 for detection of Alzheimer’s disease. The electrode modification process was characterized by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and Field emission scanning electron microscopy (FESEM). some factors influencing the performance of the amperometric immunosensor were optimized. The experiment outcome indicates a conducting layer of the nanocomposites on the FTO coated glass at range of -1.5 to 0.5V at 0.10Vs-1 in a solution 10 ml of PAni-Fe3O4 nanocomposites. Electrochemical impedance changes occur only after PAni/Fe3O4 bound to surface of bare FTO, confirming the deposition and indicating that the new modified electrode can be used as a transducing matrix for the immobilization of biomarker. Tests performed with this immunosensor showed good linearity with a detection limit of 0.061 µg/mL-1 at 3σ

Key words: Immunosensor , Polyaniline , Nanocomposites , Conductivity , Fe3O4 , β-Amyloid