US Patent 7267750 Biosensor

A biosensor comprising: an electrically insulating base plate; an electrode system comprising a working electrode and a counter electrode formed on the base plate; a cover member which is joined to the base plate to form a sample solution supply pathway for supplying a sample solution to the electrode system between the cover member and the base plate; and a reagent system comprising at least an oxidoreductase and an electron mediator disposed in the sample solution supply pathway, wherein the electron mediator is provided on the base plate and the oxidoreductase is provided on the cover member such that the electron mediator and the oxidoreductase are not in contact with each other.