Electrochemical sensing of glucose using polyaniline nanofiber dendrites-amperometric and impedimetric analysis

A novel electrochemical synthesis of polyaniline (PANI) nanofiber dendrites on platinum electrodes using p-toluenesulfonic acid for sensing of glucose is reported. The characterization of PANI is carried out using scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and ultraviolet (UV)-visible spectral studies. The electrochemical behavior of the PANI-coated electrode is investigated with the help of cyclic voltammetry, chronoamperometry, and impedance spectroscopy, regarding its efficacy as a glucose sensor. The amperometric analysis shows a very low detection limit of ∼100 nM with the linear regime spanning 50 μM-12 mM, while the response time is <5 s. The Michaelis-Menten constant is estimated as 1.24 × 10-2 M indicating the high activity of the glucose oxidase enzyme. The equivalent circuit fitting of the Nyquist and Bode' plots is carried out to estimate the system parameters. The reliability of the PANI coated electrodes is demonstrated by procuring the authentic samples from the hospitals. The stability and reproducibility of the sensor is also analyzed. Copyright © 2012 Wiley Periodicals, Inc.