An Amperometric Glucose Biosensor With Enhanced Measurement Stability and Sensitivity Using an Artificially Porous Conducting Polymer

Abstract

A conducting polymer [polypyrrole (PPy)]-based amperometric biosensor fabricated on a platinum-coated nanoporous alumina electrode has been described. This fabricating process introduced artificial porosity into the PPy film, and the template pore sizes were carefully chosen to match the size of the glucose oxidase (GOx) molecule. The PF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-</sup> -doped PPy film was synthesized with 0.05 M pyrrole and 0.1 M NaPF <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">6</sub> at a current density of 0.3 mA/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> for 90 s. Immobilization was done by physically adsorbing 5 muL of GOx on the nanoporous PPy film. Glutaraldehyde (0.1 wt.%, 5 muL) was used for cross-linking. The synthesized films were characterized by using an electrochemical technique and scanning electron microscopy (SEM). Amperometric responses were measured as a function of different concentrations of glucose at 0.4 V. Nanoporous electrodes lead to high enzyme loading, whereas the use of a cross-linking agent increased stability, sensitivity, reproducibility, repeatability, and shelf life.