Glucose sensing electrodes based on a poly(3,4-ethylenedioxythiophene)/Prussian blue bilayer and multi-walled carbon nanotubes

• Published in: Biosensors & bioelectronics 2009-03, Vol.24 (7), p.2015-2020
• Main Authors: Chiu, Jing-Yang, Yu, Chung-Mu, Yen, Miao-Ju, Chen, Lin-Chi
• Format: Article
• Language: English
• Subjects: Adsorption; Biological and medical sciences; Biosensing Techniques - instrumentation; Biosensors; Biotechnology; Bridged Bicyclo Compounds, Heterocyclic - chemistry; Electrochemistry - instrumentation; Enzymes, Immobilized - chemistry; Equipment Design; Equipment Failure Analysis; Ferrocyanides - chemistry; Flexible biosensor; Flow-injection assay (FIA); Fundamental and applied biological sciences. Psychology; Glucose; Glucose - analysis; Glucose Oxidase - chemistry; Methods. Procedures. Technologies; Microelectrodes; Multi-walled carbon nanotubes (MWCNTs); Nanotechnology - instrumentation; Nanotubes, Carbon - chemistry; Nanotubes, Carbon - ultrastructure; Poly(3,4-etheylenedioxythiophene) (PEDOT); Polymers - chemistry; Prussian blue (PB); Reproducibility of Results; Screen printing; Sensitivity and Specificity; Various methods and equipments
• ISSN: 0956-5663; 1873-4235
• DOI: 10.1016/j.bios.2008.10.010

Here we report a new glucose sensing electrode based on a poly(3,4-ethylenedioxythiophene) (PEDOT)/Prussian blue (PB) bilayer and multi-walled carbon nanotubes (CNT). The bilayer was prepared on a flexible screen-printed carbon electrode (SPCE) by sequential electrodeposition. The inner PB layer was electrodeposited first for detecting H2O2 from glucose oxidation; the outer PEDOT layer was electropolymerized on a baked or an unbaked PB film to entrap glucose oxidase (GOD). It was observed that the stability of PB in phosphate buffered saline (pH 7.4) was attained by post-deposition bake at 100°C and the outer PEDOT layer both. In addition, a baked PB film enhanced the subsequent PEDOT growth and the corresponding GOD entrapment. As a result, the bilayer enzyme electrode showed highly resolved and reproducible signals (R.S.D.=2.54%) to glucose samples from 100μM to 1M during a flow-injection analysis (FIA) at −0.1V vs. Ag/AgCl. The sensitivity of the linear range (1–10mM) was 2.67μAcm−2mM−1. Moreover, the electrode retained ca. 82% of the original response after 1-month storage in PBS, pH 6.0 at 4°C and could determine the glucose level in human serum precisely. Besides, it was found that CNT incorporation could further improve the sensitivity and could achieve μM-range glucose detection.