Reagentless Amperometric Immunosensor Based on Human Immunodefficiency Virus Diagnosis Marker Glycoprotein 160 Antibody Coated Gold-magnetic Particles Modified Electrode

A novel amperometric immunosensor for human immunodefficiency virus (HIV) glycoprotein 160 (gp160) based on nanoAu/Fe3O4/Chitosan(chit) composite film as immobilization matrix was investigated. Firstly, the complex [Cu(bpy)(2) (H2O)](2) (C6H8O4)(2) (ClO4)(4), (CuL) was prepared and adsorbed on the surface of glassy carbon electrode(GCE), then nanoAu/Fe3O4/Chitosan composite film was modified on the surface of GCE|CuL and HIV gp160 antibody was furthermore immobilized on the surface to form one gp160 immunosensor(GCE|CuL/nanoAu/Fe3O4/Chit/anti gp160). CuL can be employed as an electron transfer mediator for catalytic activity detection of H2O2. After the immunosensor was incubated with HIV gp160 solution at 37 degrees C for 30 min, the electron transfer access of CuL to H2O2 Is partly inhibited, which led to a linear decrease of the catalytic efficiency to H2O2 by the oxidation of immobilized CuL by H2O2 at - 300 mV in pH 7.0 PBS. Under the optimal conditions, the linear range of gp160 by the immunosensor is 1-400 mu g/L and the detection limit is 0.5 mu g/L at 3 times noise. The immunosensor shows more sensitivity and accuracy than that only modified by gp160 antibody coated nano Au/chitosan film. This method simplifies the detection system without adding electron transfer media to solution and shortens the analytical time with one-step Immunoassay, thus would be valuable for clinical immunoassay for HIV gp160 in AIDs patients' serums