Amperometric glucose biosensors based on redox polymer-mediated electron transfer

Abstract

Electrical communication between the flavin adenine dinucleotlde redox centers of glucose oxidase and a conventional carbon paste electrode has been achieved by using electron-transfer relay systems based on polyslloxanes. Six materials for amperometric biosensors are described In which ferrocene and dlmethylferrocene electron relays are covalently attached to Insoluble slloxane polymers. Sensors containing these polymeric relay systems and glucose oxidase respond rapidly to glucose, with steady-state current responses achieved In less than 10 s. The response to glucose under N2 saturation shows apparent Michaells-Menten constants, *VPP, In the range 16-71 mM and limiting current densities, ymax, of 29-275 µ /cm2. The dependence of the sensor response on the nature of the slloxane polymer and the type of polymer-bound relay Is discussed.

Glucose Amperometric Biosensor Based on the Co-immobilization of Glucose Oxidase (GOx) and Ferrocene in Poly(pyrrole) Generated from Ethanol / Water Mixtures

“…0.75 µA mmol -1 L cm -2 working at 0.35 V (vs. SCE) and similar values (0.625 µA mmol -1 L cm -2 ) were found by Foulds and Lowe 12 measuring at 0.3 V. All these biosensors perform better than the Ppy/GOx electrode but they are worse than the electrode prepared from ethanolic solutions. Very much higher sensitivities are obtained with biosensors prepared by immobilizing ferrocene containing siloxane copolymers and GOx in carbon paste electrodes 21 , but it must be taken Figure 4 shows the amperometric response of the biosensor at 0.65 V both in air and N 2 -saturated buffer solutions. It can be seen that the signal obtained is higher in N 2 -saturated media than in air.…”

Electrochemical and bioelectrocatalytical properties of novel block-copolymers containing interacting ferrocenyl units

“…Long-range electrón transfer to active sites of these enzymes has been demonstrated, both with enzymes in solution and co-immobilized in two-and three-dimensional surface polymer structures [26]. Several authors have reported that polymers and dendrimers functionalized with ferrocene groups can effectively medíate the electrón transfer to glucose oxidase [27][28][29].…”

Biosensors Based on Ultrathin Film Composite Membranes

“…In order to demonstrate the feasibility of this new approach for sensor design, we have prepared and evaluated a prototype electrochemical glucose sensor. This particular sensor was chosen to demonstrate the feasibility of this new sensor-design concept because the molecular recognition and signal transduction chemistries are well established (8)(9)(10)(11). A number of other sensing schemes (12-16) could, however, have been chosen.…”