A BILIRUBIN BIOSENSOR BASED ON A MULTILAYER NETWORK ENZYME ELECTRODE

This paper describes the construction of a bilirubin oxidase multilayer electrode that responds amperometrically to bilirubin concentration. The enzyme electrode was constructed by the covalent attachment of bilirubin oxidase layers to a self-assembled monolayer of 3-mercaptopropionate ester, which was associated with a gold surface. Electron transfer from the enzyme redox site to the electrode was mediated by ferrocene carboxylic acid. The multilayer electrode responded linearly to bilirubin concentration in solution. In contrast to the native enzyme, which is unstable, the bilirubin oxidase multilayer electrode was stable, and its shelf-life was more than three months at 4 degrees C. The amperometric response of the enzyme electrode towards bilirubin was dependent on the albumin concentration in the system. By adjustment of this concentration to the value present in newborns' serum, a calibration curve for the amperometric response as a function of bilirubin was deduced. The concentration of bilirubin in serum samples from newborns was determined.