| abstract |
A sensor which detects biologically, in particular enzymatically, decomposable substances in a biological substrate by means of an electrode (2) and at least one membrane which covers the electrode (2), has at least three membranes (3, 4, 5, 6), of which at least two contain each at least one enzyme for reacting with the biological substance to be determined and/or a reactant for a reaction product of the enzymatic reaction. At least one additional membrane (3, 5) sets the distance between said membranes (4, 6) and/or is arranged as a permselective membrane. |