Progress towards in vivo glucose sensing with a ferrocene-mediated amperometric enzyme electrode

A range of miniature, amperometric enzyme electrodes have been constructed using the principle of mediated transfer of electrons. Ferrocene, or one of its derivatives, can be used in conjunction with immobilised glucose oxidase to produce sensors which are linear to at least 20 mmol/l glucose, have fast response times, are relatively oxygen insensitive and are suitable for implantation studies. In preliminary experiments in non-diabetic pigs, electrode responses followed blood responses, although mean tissue levels were about one fifth of those in blood. The ferrocene technology thus appears to be suitable for adaptation to the construction of implantable glucose electrodes for use in diabetic man.