Study on Potentiometric Glucose Biosensor Based on Separative Extended Gate Field Effect Transistor

In this study, we present a potentiometric glucose biosensor based on a separative extended gate field effect transistor (EGFET) claimed in 2000. The biosensor was coated a sensing thin film, SnO2, on a plastic substrate by using radio frequency (R.F.) sputtering method of semiconductor technology. The good conductive and light characteristics of indium tin oxide/polyethyleneterephthalate (ITO/PET) substrate make it be very suitable to fabricate miniaturized pH electrode and biosensor. Further, chitosan (Chi) and mediator of multi-wall carbon nano-tubes (MWCNTs) was used in this glucose biosensor manufacture, and utilized 3-Glycidoxypropyltrimethoxysilane (3-GPTS) to entrap enzyme of glucose oxidase (GOD) by one-step simple fabrication. As well as, due to the directly transfer electron (DTE) effect of MWCNTs, the output voltage responses of the potentiometric glucose biosensor were up from 150 mV to 200 mV, and the detection linear range was from 100 mg/dl to 300 mg/dl. Finally, the biosensor has a 4-days life time and 25-times operational stability.