One Novel Nano Fe3O4-Au Modified Amperometric Immunosensor for Human Immunodeficiency Virus p24 Antigen

A novel nano Fe₃O₄-Au modified amperometric immunosensor for rapid separation-free determination of human immunodeficiency virus (HIV) p24 antigen in acquired immunodeficiency syndrome (AEDs) patients´ serum is proposed. Firstly, one novel sebacato-bridged Cu(II) phen complex Cu(phen)L₂ (referred to as CuL, H₂L=sebacic acid; phen=1,10phenanthroline) was absorbed on the surface of glassy carbon electrode (GCE), then gold magnetic nanoparticles Fe₃O₄Au/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 Fe₃O₄-Au colloid to construct an GCE|CuL/Fe₃O₄-Au/Ab-p24 immunosensor. The modified electrode were characterized by cyclic voltammetry (CV), scanning electron microscope (SEM), and X-ray 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 antip24 immobilized on the working electrode (WE), which leads to a linear decrease of the catalytic efficiency of H₂O₂ in p24 concentration ranges from 0.5 ~ 90 ng/mL with the detection limit of 0.2 ng/mL (3sigma). 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.