A novel nano Fe 3 O 4 -Au modified amperometric immunosensor for rapid separation-free determination of human immunodeficiency virus (HIV) p24 antigen in acquired immunodeficiency syndrome (AIDs) patients' serum is proposed. Firstly, one novel sebacato-bridged Cu(II) phen complex Cu(phen)L 2 (referred to as CuL, H 2 L=sebacic acid; phen=1,10phenanthroline) was absorbed on the surface of glassy carbon electrode (GCE), then gold magnetic nanoparticles Fe 3 O 4 -Au/Chit composite was immobilized onto the surface of CuL modified GCE by its excellent membrane-forming ability, and finally the anti-p24 was adsorbed onto the surface of Fe 3 O 4 -Au colloid to construct an GCE|CuL/Fe 3 O 4 -Au/Ab-p24 immunosensor. The modified electrode were characterized by cyclic voltammetry (CV), scanning electron microscope (SEM), and Xray photo electron spectrum (XPS). Based on a competition immunoreaction, CV method for p24 antigen was established. The decrease of current results from the competition of HRP labeled p24 antigen (HRP-p24) and p24 in serum samples to anti-p24 immobilized on the working electrode (WE), which leads to a linear decrease of the catalytic efficiency of H 2 O 2 in p24 concentration ranges from 0.5 ~ 90 ng/mL with the detection limit of 0.2 ng/mL (3 ). The proposed method needs neither separation nor washing up step, which simplifies the immunoassay procedure, shortens the analytical time, and provides a new promising platform to diagnosing the AIDs disease.
Keywords-Sebacato-bridged Cu(II) phen complex; amperometric immunosensor; HIV p24 antigen; Fe 3 O 4 -Au colloidI.