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.