A BILIRUBIN BIOSENSOR BASED ON A MULTILAYER NETWORK ENZYME ELECTRODE

This paper describes the construction of a bilirubin oxidase multilaye r electrode that responds amperometrically to bilirubin concentration. The enzyme electrode was constructed by the covalent attachment of bi lirubin oxidase layers to a self-assembled monolayer of 3-mercaptoprop ionate ester, which was associated with a gold surface. Electron trans fer from the enzyme redox site to the electrode was mediated by ferroc ene carboxylic acid. The multilayer electrode responded linearly to bi lirubin concentration in solution. In contrast to the native enzyme, w hich is unstable, the bilirubin oxidase multilayer electrode was stabl e, and its shelf-life was more than three months at 4 degrees C. The a mperometric response of the enzyme electrode towards bilirubin was dep endent on the albumin concentration in the system. By adjustment of th is concentration to the value present in newborns' serum, a calibratio n curve for the amperometric response as a function of bilirubin was d educed. The concentration of bilirubin in serum samples from newborns was determined.