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

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 (R(2)=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 (R(2)=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.