A glucose biosensor based on the synergistic action of nanometer-sized TiO2 and polyaniline

Polyaniline/active carbon (PANI) and nanometer-sized TiO2 (n-TiO2) were prepared by oxidation and sol-gel methods, respectively, and were then used as a zymophore to modify a glassy carbon electrode (GCE) and a GOx/n-TiO2/PANI/GCE sensor with a synergistic effect was established. A series of performance evaluations for the modified material and sensor was studied in detail through cyclic voltammetry (CV) and a chronoamperometry (CA) method. The results showed that the sensor had a good response to glucose and that the electron of the GOx molecule was transferred directly onto the sensor, and a linear relationship between the GOx redox peak current and the sweep speed was found. The apparent transmission speed constant, k, for dissimilar electrode charges was 1.35s(-1), 95% of the maximum steady current for the GOx/n-TiO2/PANI/GCE sensor could be reached in 10s, the linear range of the detected glucose concentration was from 0.02 mM to 6.0mM, the sensitivity was 6.31 μA mM(-1)cm(-2), and the limit of detection was 18 μM. The sensor had good selectivity and stability and could be maintained at 82% of the initial activity for 30 days.