High-sensitivity urea sensor based on the composite film of electroinactive polypyrrole with polyion complex

A high-sensitivity urea sensor consisting of the composite film of electropolymerized electroinactive polypyrrole (PPy) with the polyion complex containing urease (Urs) was fabricated. This sensor showed potential response to urea within 20 s by detection of pH change during enzymatic reaction with a pH-sensitive electroinactive PPy. The urea response became higher with the slope of 110 mV decade(-1). This high sensitivity was attributed to the effective immobilization of the large number of Urs by electropolymerization on the electrode pre-coated with polyion complex.