Direct electrochemistry of hemoglobin and biosensing for hydrogen peroxide using a film containing silver nanoparticles and poly(amidoamine) dendrimer

A new architecture for a biosensor is proposed using a glassy carbon electrode (GCE) modified with hemoglobin (Hb) and silver nanopartides (AgNPs) encapsulated in poly(amidoamine) dendrimer (PAMAM). The biosensors were characterized using ultraviolet-visible spectroscopy, zeta-potential and cyclic voltammetry to investigate the interactions between Hb, AgNPs and the PAMAM film. The biosensor exhibited a well-defined cathodic peak attributed to reduction of the Fe3+ present in the heme group in Hb, as revealed by cyclic voltammetry in the presence of O-2. An apparent heterogeneous electron transfer rate of 4.1 s(-1) was obtained. The Hb-AgNPs-PAMAM/GCE third generation biosensor was applied in the amperometric determination of hydrogen peroxide over the linear range from 6.0 x 10(-6) to 9.1 x 10(-5) mol L-1 with a detection limit of 4.9 x 10(-6) mol L-1. The proposed method can be extended to immobilize and evaluate the direct electron transfer of other redox enzymes. (C) 2015 Elsevier B.V. All rights reserved.