Development of a creatinine-sensitive sensor for medical analysis

Low-cost, disposable, SiO2/Si3N4 chemical field effect transistor (ChemFET) microsensors have been fabricated for pH measurements and adapted to biochemical applications by using polyvinyl alcohol (PVA) enzymatic layers deposited and patterned either by dip-coating, or spin-coating and photolithographic techniques. Both processes have been compared for the development and optimization of a creatinine-sensitive enzymatic field effect transistor (Creatinine-EnFET). Creatinine detection properties have been characterized in dialysate, demonstrating better properties for the spin-coated PVA enzymatic layers. Thus, creatinine sensitivity has been estimated at approximately 30 mV/pCreatinine on the [10-1000 mumol L-1] concentration range. The microsensor will be used for blood analysis and more precisely for haemodialysis. (C) 2004 Elsevier B.V. All rights reserved.