Flexible SnO2 Substrate-Based Potentiometric Thick-Film Solid-State Urea Biosensor?

[[abstract]]A flexible structure solid-state biosensor for urea detection based on a polyethylene terephthalate (PET) substrate was presented in this study. Urea is identified using enzyme-based biosensors, in which an enzyme layer lies directly on the surface of a sensor, which measures the concentration of products formed during an enzymatic reaction. The mechanism of the biosensors is based on ammonium ions forming in the course of the reaction directly on the surface of the ammonium ion-selective membrane. Experimental results indicate that the ammonium ion-selective membrane exhibited good sensitivity and operational stability in the range of 10(-4) M to 1 M ammonium concentrations. Additionally, the presented flexible substrate-based urea biosensors showed linear range between 0.026 mM and 10 mM urea concentrations. Moreover, response time, detection limit, and pH effect are considered.[[note]]SC