Direct electrochemistry and electrocatalysis of reduced glutathione on CNFs–PDDA/PB nanocomposite film modified ITO electrode for biosensors

The electrochemical oxidation of reduced glutathione (GSH) catalyzed by electro generated Berlin green at carbon nanofibers–poly(diallyldimethylammonium chloride)/Prussian blue (CNFs–PDDA/PB) nanocomposite film modified ITO electrode has been studied. The CNFs–PDDA/PB nanocomposite film were fabricated by casting the composite CNFs enfolded PDDA on ITO electrode followed by electrochemical deposition of PB on the CNFs–PDDA matrix using cyclic voltammetry (CV). Electron microscopy (TEM, AFM), and Fourier transform infrared spectroscopy (FT-IR) studies were used to characterize the morphology and structure of the nanocomposite. The fabricated CNFs–PDDA/PB/ITO nanocomposite film electrode shows significant improvement of redox activity of PB due to the excellent electron transfer ability of CNFs. It was also found to possess prominent electrocatalytic activity toward the oxidation of glutathione with high sensitivity as high as 2.07 μA dm3 mol−1 cm−2. A nontoxic, stable and convenient method for the detection of GSH in the concentration range of 6.0 × 10−6 to 1.74 × 10−5 M has been developed and it showed improved sensor performance compared to the unmodified PB electrode. The high sensitivity, wider linear range, good reproducibility, and the minimal surface fouling make this CNFs/PDDA/PB nanocomposite film a promising candidate for GSH sensors.