An acrylamide biosensor based on immobilization of hemoglobin onto multiwalled carbon nanotube/copper nanoparticles/polyaniline hybrid film

A method is described for the construction of a highly sensitive electrochemical biosensor for the detection of acrylamide, based on covalent immobilization of hemoglobin (Hb) onto carboxylated multiwalled carbon nanotube/copper nanoparticle/polyaniline (c-MWCNT/CuNP/PANI) composite electrodeposited onto pencil graphite (PG) electrode. The enzyme electrode was characterized by cyclic voltammetry (CV), scanning electron microscopy (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, and electrochemical impedance spectroscopy (EIS). The biosensor showed an optimal response at pH 5.5 (0.1 M sodium acetate buffer) and 35 °C when operated at 20 mV s−1. The biosensor exhibited low detection limit (0.2 nM) with high sensitivity (72.5 μA/nM/cm2), fast response time (<2 s), and wide linear range (5 nM to 75 mM). Analytical recovery of added acrylamide was 95.40 to 97.56%. Within- and between-batch coefficients of variation were 2.35 and 4.50%, respectively. The enzyme electrode was used 120 times over a period of 100 days, when stored at 4 °C.