Direct Electrochemistry and Electrocatalysis of Hemoglobin at PAMAM Dendrimer-MWNTs-Au Nanoparticles Composite Film Modified Glassy Carbon Electrode

The direct electron transfer of hemoglobin at the PAMAM-MWNTs-AuNPs composite film modified glassy carbon electrode was studied. In a phosphate buffer solution(PBS, pH=7.0), the formal potential(E0') of Hb was –0.105 V versus SCE, the electron transfer rate constant was 4.66 s–1. E0′ of Hb at the modified electrode was linearly varied in a pH range of 5.0-8.0 with a slope of –49.2 mV/pH. The Hb/PAMAM-MWNTs-AuNPs/GCE gave an excellent electrocatalytic response to the reduction of hydrogen peroxide. The catalytic current increased linearly with H2O2 concentration in a range of 1.0×10?6 to 2.2×10?3 mol/L. The detection limit was 2.0×10?7 mol/L at a signal to noise ratio of 3. The Michaelis-Menten constant(Kmapp) was 2.95 mmol/L.