Multilayer Assembly of Hemoglobin and Colloidal Gold Nanoparticles on Multiwall Carbon Nanotubes/Chitosan Composite for Detecting Hydrogen Peroxide

Chitosan (CS) was chosen for dispersing multi‐wall carbon nanotubes (MWNTs) to form a stable CS‐MWNTs composite, which was first coated on the surface of a glassy carbon electrode to provide a containing amino groups interface for assembling colloidal gold nanoparticles (GNPs), followed by the adsorption of hemoglobin (Hb). Repeating the assembly step of GNPs and Hb resulted in {Hb/GNPs}_n multilayers. The assembly of GNPs onto CS‐MWNTs composites was confirmed by transmission electron microscopy. The consecutive growth of {Hb/GNPs}_n multilayers was confirmed by cyclic voltammetry and UV‐vis absorption spectroscopy. The resulting system brings a new platform for electrochemical devices by using the synergistic action of the electrocatalytic activity of GNPs and MWNTs. The resulting biosensor displays an excellent electrocatalytic activity and rapid response for hydrogen peroxide. The linear range for the determination of H₂O₂ was from 5.0×10^?7 to 2.0×10^?3 M with a detection limit of 2.1×10^?7 M at 3σ and a Michaelis–Menten constant K_M^app value of 0.19 mM.