Modification of polypyrrole nanowires array with platinum nanoparticles and glucose oxidase for fabrication of a novel glucose biosensor Original Research Article

A novel glucose biosensor, based on the modification of well-aligned polypyrrole nanowires array (PPyNWA) with Pt nanoparticles (PtNPs) and subsequent surface adsorption of glucose oxidase (GOx), is described. The distinct differences in the electrochemical properties of PPyNWA–GOx, PPyNWA–PtNPs, and PPyNWA–PtNPs–GOx electrodes were revealed by cyclic voltammetry. In particular, the results obtained for PPyNWA–PtNPs–GOx biosensor showed evidence of direct electron transfer due mainly to modification with PtNPs. Optimum fabrication of the PPyNWA–PtNPs–GOx biosensor for both potentiometric and amperometric detection of glucose were achieved with 0.2 M pyrrole, applied current density of 0.1 mA cm−2, polymerization time of 600 s, cyclic deposition of PtNPs from −200 mV to 200 mV, scan rate of 50 mV s−1, and 20 cycles. A sensitivity of 40.5 mV/decade and a linear range of 10 μM to 1000 μM (R2 = 0.9936) were achieved for potentiometric detection, while for amperometric detection a sensitivity of 34.7 μA cm−2 mM−1 at an applied potential of 700 mV and a linear range of 0.1–9 mM (R2 = 0.9977) were achieved. In terms of achievable detection limit, potentiometric detection achieved 5.6 μM of glucose, while amperometric detection achieved 27.7 μM.