A new amperometric cholesterol biosensor based on poly(3,4-ethylenedioxypyrrole)

Cholesterol oxidase (ChOx) was physically entrapped in poly(3,4-ethylenedioxypyrrole) (PEDOP) to construct an amperometric cholesterol biosensor. The responses of the enzyme electrodes were measured via monitoring oxidation current of H2O2 at +0.7 V in the absence of a mediator. Kinetic parameters, operational and storage stabilities, pH and temperature dependencies were determined. Km, Imax and sensitivity (Imax/Km) were calculated as 3.4 mM, 34 μA cm−2 and 10 μA mM−1 cm−2, respectively. The minimum detectable substrate concentration was 0.4 mM and for a period of 20 days the biosensor showed the maximum relative activity.