Glucose oxidase immobilization by volume shrinkage of graphene as "door-function" microelectrode

Porous graphene microelectrode was constructed by electrodeposition graphene on platinum (Pt) microwire (100 μmi nd iameter). It collects the synergistic advantages of good biocompatibility of electrochemically reduced graphene oxide (ERGO) and excellent electric conductivity of Pt. Based on the intrinsic volume shrinkage of ERGO during drying process, glucose oxide (GOD) has been successfully immobilized within the microelectrode. Such volume shrinkage characteristic of the ERGO microelectrode could resemble the "door-function". The microelectrode functioned as a door, referred to "door-function" microelectrode. The state of the door could be modulated from fully open to fully close state by controlling the drying time. The GOD immobilization was achieved without using any additional binders such as chitosan and nation film. Direct electrochemistry of the adsorbed GOD was always available to exhibit satisfactory performance in a wide range of pH. This novel enzyme immobilization technique provides a promising pathway for development of various biosensing devices.