Amperometric Glucose Biosensor Based on Sol-Gel-Derived Zirconia/Nafion Composite Film as Encapsulation Matrix

摘要

An amperometric glucose biosensor has been developed based on the use of the nanoporous composite film of sol-gel-derived zirconia and perfluorosulfonated ionomer,Nafion,for the encapsulation of glucose oxidase (GOx) on a platinized glassy carbon electrode.Zirconium isopropoxide (ZrOPr) was used as a sol-gel precursor for the preparation of zirconia/Nafion composite film and the performance of the resulting glucose biosensor was tuned by controlling the water content in the acid-catalyzed hydrolysis of sol-gel stock solution.The presence of Nafion polymer in the sol-gel-derived zirconia in the biosensor resulted in faster response time and higher sensitivity compared to those obtained at the pure zirconia- and pure Nafion-based biosensors.Because of the nanoporous nature of the composite film,the glucose biosensor based on the zirconia/Nafion composite film can reach 95% of steady-state current less than 5 s.In addition,the biosensor responds to glucose linearly in the range of 0.03-15.08 mM with a sensitivity of 3.40 muA/mM and the detection limit of 0.037 mM (S/N = 3).Moreover,the biosensor exhibited good sensor-to-sensor reproducibility (approx 5%) and long-term stability (90% of its original activity retained after 4 weeks) when stored in 50 mM phosphate buffer at pH 7 at 4 deg C.