NOVEL THIN FILM STRUCTURES

A thin film structure, which comprises a substrate with a thin conductive layer containing an oxidizing enzyme mixed with an electron transfer mediator. The mixture of the enzyme and the mediator contains a conductive ink which comprises an electrically conductive component selected from the group consisting of carbon nanotubes, metal particles, carbon particles and inherently conductive polymers and mixtures thereof and, optionally, a binder. The thin layer is protected against wetting to allow for its storage in dry conditions, and it is sufficiently porous to allow for immediate activation of the oxidizing enzyme when contacted with an aqueous solution.