Amperometric Glucose Biosensor Based on Entrapment of Glucose Oxidase in a Poly(3,4‐ethylenedioxythiophene) Film

Abstract

In this study, conducting polymer, poly(3,4-ethylenedioxythiophene) (PEDOT), is used as a matrix for the entrapment of glucose oxidase (GOD) and served as the working electrode for sensing glucose. The monomer, EDOT, is electropolymerized onto the platinum electrode by the cyclic voltammetric (CV) technique, scanned between 0.2 and 1.2 V (vs. Ag/AgCl/saturated KCl) in a phosphate buffer solution (PBS) containing GOD, which is entrapped into the PEDOT film simultaneously. The biosensor senses the reoxidative current of the mediator, ferricinium ions, with a constant applied potential of 0.35 V in the sensing system containing a phosphate buffer solution, ferricinium ions, and glucose. The indirect electrochemical method can efficiently reduce the sensing potential of the glucose. The sensing results show that the linear range of the calibration curve for the glucose concentration lies between 0.1 and 10.0 mM, which is a suitable level in the human body. Besides, the limit of detection and sensing sensitivity on glucose for the biosensor are 0.13 mM and 12.42 mA cm À2 M À1 , respectively. The response time of the biosensor, which is defined as the reaction current reaching 95% of the steady-state current, is about 4 -10 s. In the aspects of interferences on ascorbic acid (AA) and uric acid (UA), the sensing currents increased about 9.7% and 39.1%, respectively, when compared to the sensing current of glucose. Moreover, the biosensor shows a good stability in which the sensing current of the electrode retains 80% of its original one over a period of 18 days.

Facile Synthesis of Leaf‐Like CuO Nanoparticles and Their Application on Glucose Biosensor

“…Its important for human health to maintain the concentration of blood sugar at a definite level, thus glucose detection is extremely important especially to the patients suffering from diabetes [1,2]. Glucose oxidase (GOD) has been widely applied to fabricate diverse amperometric biosensors for glucose detection [3][4][5][6][7][8][9] due to its high sensitivity and selectivity to glucose and stable activity. "Finger pricking" is commonly used method by diabetic patients for measuring their blood sugar level.…”

Amperometric Enzyme-based Biosensors for Lowering the Interferences

“…According to the UV spectrum (not shown) of the electrolyte at 280 nm, which is the maximum absorbent wavenumber for GOD, the leakage of GOD in the electrolyte was calculated to be about 132 U and the entrapped efficiency was about 33% for the electrode B. The immobilized amount of GOD by this method is about 68 U/cm 2 which is higher than 0.101 U/cm 2 of the GC electrode by entrapping enzyme and polymerizing PEDOT at the same time reported in the previous work (Nien et al, 2006).…”

“…They all show that the PEDOT is a suitable material for electrochemical biosensor, so it was mainly acted as the matrix to entrap the enzyme in the studies. According to the literatures, PEDOT film not only can entrap glucose oxidase (Fabiano et al, 2002;Nien et al, 2006) or polyphenol oxidase (Vedrine et al, 2003) to fabricate a specific biosensor, but also detect single strand DNA directly (Krishnamoorthy et al, 2004). In this chapter, two systems were reviewed to cover a good interference-independent glucose biosensor.…”

“…(7), the Ag surface was oxidized to form a thin layer of AgCl in 0.1 M FeCl 3 solution spontaneously for 1 hr. For the enzyme-modified working electrode, the conducting polymer, PEDOT, was prepared in a flow system and the other conditions are the same as described in our previous work (Nien et al, 2006). The PEDOT film was obtained by electropolymerization of EDOT with the sweeping potential from 0.2 to 1.2 V for 20 cycles at a flow rate of 5 ml/hr and it was used as a matrix to entrap the glucose oxidase for immobilization on "WE1" (in Fig.…”

Properties and Customization of Sensor Materials for Biomedical Applications

“…CPs have been successfully used in the preparation of biosensors in order to entrap enzymes in situ; however, in certain cases the high enzyme loading has proven to impede the electropolymerization of the CP (158). It should also be noted that, if hydrogen peroxide is developed as a by-product of the oxidase enzymatic substrate conversion during the sensor activity, this compound can cause the overoxidation of the CP and limit the lifetime of the sensor (12).…”