Urea impedimetric biosensor based on polymer degradation onto interdigitated electrodes

The measurement of urea was accomplished with an interdigitated electrode by using ac impedance spectroscopy to follow capacitance changes, which were produced during enzyme-catalyzed dissolution of a polymer coating. The employed coating was the enteric polymer Eudragit S-100, on which urease enzyme was immobilized by carbodiimide coupling. Urea was determined in the 0.02–2 M range, proving that the combination of the biofunctionalized electrode and the impedance technique results in an elegant approach for urea biosensing.