Direct electrochemistry of hemoglobin based on nano-composite film of gold nanopaticles and poly (diallyldimethylammonium chloride) functionalized graphene

The poly (diallyldimethylammonium chloride) (PDDA) functionalized graphene nanosheets (PDDA-G) were prepared and gold nano-particles (AuNPs) were assembled on the surface of PDDA-G film through electrostatic interaction to construct the biocompatible interface. The resulting AuNPs/PDDA-G nanocomposite film exhibited enhanced capability for hemoglobin (Hb) immobilization and realized its direct electrochemistry. The surface concentration (Γ*) of electroactive Hb on the surface of GCE was calculated to be 3.85 × 10−9 mol/cm2. Moreover, the AuNPs/PDDA-G based sensor showed prominent electrocatalytic activity for the detection of H2O2 with a wide linear range from 6 μM to 1010 μM and a low detection limit of 0.39 μM at 3σ. Meanwhile, the apparent Michaelis–Menten constant (Km) was 0.51 mM. This biosensor exhibited high sensitivity and fast responses, which may provide a novel way for fabrication of other graphene based sensors and broaden the application of graphene in biosensing.

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► AuNPs/PPDA-G multi-material has been fabricated which has high biocompatibility.
► AuNPs/PPDA-G multi-nanomaterials exhibited enhanced capability for hemoglobin immobilization.
► The larger surface concentration (Γ*) of electroactive Hb was 3.85 × 10−9 mol/cm2.
► The biosensor showed prominent electrocatalytic activity for H2O2.
► The lower apparent Michaelis–Menten constant (Km) was 0.51 mM, shown hemoglobin retaining its high bioactivity for H2O2 oxidation.