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

•A biocompatible PSMA-g-3ABA/MWCNT nanocomposite was used for sensor fabrication.•The nanocomposite exhibited an excellent ability towards the immobilization of Hb.•The biosensor exhibits an excellent activity towards the reduction of H2O2.•The proposed biosensor showed high sensitivity and sub-micro molar detection limits.

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 × 10− 6 M to 5.0 × 10− 4 M with a detection limit of 3.2 × 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.