Poly(dicarbazole-N-hydroxysuccinimide) film: a new polymer for the reagentless grafting of enzymes and redox mediators

Upon oxidative electropolymerisation of a new dicarbazole derivative functi onalised by a N-hydroxysuccinimide group in acetonitrile, electroactive pol y(dicarbazole) films were formed on electrodes. The subsequent chemical fun ctionalisation of the poly(dicarbazole) film was easily performed by succes sive immersions in aqueous enzyme and mediator solutions. Investigations by cyclic voltammetry showed that thionine and toluidine blue o have been irr eversible bound to the poly(dicarbazole) backbone. The amperometric respons es of the poly(dicarbazole) films grafted with polyphenol oxidase (PPO) and thionine to catechol were then investigated at -0.2 V vs. SCE. The catecho l sensitivity and the maximum current at saturating catechol concentrations were 14.57 mA M-1 cm(-2) and 15.43 muA cm(-2), respectively. The compariso n of this catechol sensitivity with that of a poly(dicarbazole) film only m odified with PPO (3.40 mA M-1 cm(-2)) highlighted the improvement of the bi osensor performance brought by thionine as immobilised redox mediator. (C) 2000 Elsevier Science S.A. All rights reserved.