Selective uricase biosensor based on polyaniline synthesized in ionic liquid

Abstract

The selective uricase biosensor prepared with electroactive intrinsic polyaniline (PANI) at high pH is firstly reported in this paper. Effects of electroactive interferents, such as acetaminophen, glutathione, l-cysteine and ascorbic acid on the current response of PANI-uricase biosensor were examined in the presence of their physiological normal levels with uric acid (HUr) concentration at 0.5 mmol dm-3. These well-known interferents have been shown to have no measurable effect on the biosensor's current response. In the range from 0.20 to 0.50 V, the current response increased with increasing potential. In the wide pH range from 2 to 12, current response increased with increasing pH, and the optimum pH was not appearing. We suggested the reason why the optimum pH of the PANI-uricase biosensor does not appear. The relationship between current response and uric acid concentration is good linear in the range from 1.0 × 10-3 to 1.0 mmol dm-3. The Michaelis-Menten constant K′m is 7.83 mmol dm-3 and the maximum current response imax is 58.07 μA. The current response of this biosensor increased with increasing temperature and Ea is 40.18 kJ mol-1 in the B-R buffer. The biosensor was characterized with FT-IR, UV-vis spectra and AC impedance. © 2007 Elsevier B.V. All rights reserved.