Photocurable ferrocene-containing poly(2-hydroxyl ethyl methacrylate) films for mediated amperometric glucose biosensor

Ferrocene and its derivatives have been widely used as mediators in biosensor and it is of interest to produce ferrocene-containing (or its derivatives) polymeric films for biosensor application and to prevent leaching of the mediator. In this paper, we report photocurable polymer films for the physical immobilization of ferrocene and vinylferrocene in a low hydrophilicity methacrylate polymer. The hydrophobic-hydrophilic properties of the polymers and its effect on the leaching of the entrapped ferrocene and enzyme were studied. The entrapped ferrocene compounds showed good redox behaviour in these photocured films and the films were used to fabricate a biosensor for the detection of glucose, where the enzyme glucose oxidase (GOD) was incorporated together with the mediator during the photocuring step. Very little or no leaching of the entrapped ferrocene and glucose oxidase was observed. Upon immobilization of the enzyme, the biosensor demonstrated rapid response towards glucose at low potential, yielding a linear glucose response range of 4-17 and 5-42 mM, respectively, for ferrocene and vinylferrocene films. Both glucose biosensors gave reproducibility of <10% relative standard deviations (n=6). The simple and single-step fabrication of the biosensor film is a major advantage when compared to other ferrocene-containing glucose biosensor films.