Effect of milk proteins on the behavior of a biosensor based on poly(allylamine) containing an osmium complex wired to redox enzymes Part 1. Monoenzymatic configuration

The characterization of a biosensor based on poly(allylamine) containing an osmium complex (OsPAA) in a matrix of industrial relevance, like milk, is presented. The biosensor is constructed by crosslinking an oxidase and the redox polymer (OsPAA) with poly(ethylene diglycidyl) ether (PEG). Parameter s such as the optimum crosslinker concentration, working pH and temperature , and the effect of ionic strength were examined. When the electrode was im mersed in milk spiked with substrate, an important decrease in the amperome tric signal was observed compared with the one observed in a buffer solutio n at pH 7.0. The effects of different components of the milk are presented. The decay in the catalytic current is mainly due to the caseins, which ins ulate the osmium complex from the redox center of the oxidase. (C) 2001 Els evier Science BY. All rights reserved.