A permselective biotinylated polydicarbazole film for the fabrication of amperometric enzyme electrodes

We describe herein, the synthesis and electrochemical properties of a chiral biotin derivative substituted by two carbazole groups in organic media (CH₂Cl₂). In the anodic region it has been shown by cyclic voltammetry that the oxidation of the carbazole groups has led to the first example of a cross-linked biotinylated conducting polymer. The resulting modified electrode was applied to the amperometric determination of L- and D-norepinephrines at 0.5 V vs SCE exhibiting a chiral differentiation due to a better permeation of the D-form. Furthermore, the efficient coupling of avidin and biotinylated polyphenol oxidase with the underlying biotinylated polycarbazole film has allowed the formation of an enzyme electrode. Its analytical characteristics were analyzed for the detection of L- and D-norepinephrines at -0.2 V vs SCE. The comparison with its performance to that of a conventional polyphenol oxidase electrode clearly demonstrates that the permselective properties of the polycarbazole film markedly improve the biosensor stereoselectivity.