Facile synthesis of PSMA-g-3ABA/MWCNTs nanocomposite as a substrate for hemoglobin immobilization: Application to catalysis of H2O2

The new nanocomposite films based on poly(styrene-alternative-maleic anhydride) grafted to 3-aminobenzoic acid (PSMA-g-3ABA) and multi-walled carbon nanotubes (MWCNTs) were applied to immobilize hemoglobin (Hb) for biosensor fabrication (PSMA-g-3ABA/MWCNTs). Electrochemical impedance spectroscopy was used to confirm the adsorption of Hb onto the surface of PSMA-g-3ABA/MWCNTs. The immobilized Hb maintains its bioactivities and displays an excellent electrochemical behavior. The biosensor was used to catalyze the reduction of hydrogen peroxide. The electrocatalytic response showed a linear dependence on the H2O2 concentration ranging widely from 1.0 x 10(-6) M to 5.0 x 10(-4) M with a detection limit of 3.2 x 10(-7) M. The apparent Michaelis-Menten constant of Hb on the modified electrode was estimated to be 0.22 mM. The proposed method opens a way to develop biosensors by using nanostructured materials with low electrical conductivity. (C) 2014 Elsevier B.V. All rights reserved.