A disposable amperometric biosensor for determining total cholesterol in whole blood

A disposable amperometric biosensor for detecting the total cholesterol was fabricated which comprises a sensing electrode and a reference electrode in simultaneous contact with an integrated reagent layer. The integrated reagent layer formed by coating a working ink containing cholesterol esterase, cholesterol dehydrogenase, coenzyme, redox mediator, surfactant, stabilizer, filler and at least one aqueous thickening agent. The biosensor showed the linearity for 50–500 mg/dL cholesterol acetate. The minimum detection limit of the cholesterol was 50 mg/dL. The effects of temperature and the stability of immobilized enzymes were also studied. A good correlation was found among cholesterol values obtained by commercial colorimetric test strip and clinical/laboratory methods. The biosensor showed an acceptable reproducibility, good stability and low interferences.