THIN-FILM CLARK-TYPE OXYGEN SENSOR-BASED ON NOVEL POLYMER MEMBRANE SYSTEMS FOR IN-VIVO AND BIOSENSOR APPLICATIONS

A planar miniaturized Clark-type oxygen sensor based on the Ross princ iple has been produced by means of thin-film technology. The use of a polarizable counter electrode in a three-electrode configuration allow s the regeneration of the cathodically consumed oxygen, resulting in a zero-flux amperometric oxygen sensor. The platinum working and counte r electrodes and the Ag/AgCl reference electrode were covered with a p hotostructured hydrogel layer, forming the electrolyte compartment, an d a photostructured hydrophobic gas-permeable membrane. This arrangeme nt exhibits no oxygen consumption and therefore the signal of the sens or shows almost no flow dependence. Additionally, this electrochemical feature leads to a dynamic equilibrium of the reaction products in th e hydrogel layer, overcoming the lifetime limitations caused by buffer degradation in the classical Clark principle. The sensor was tested i n buffer solutions and bovine serum, showing excellent performance and no effects of fouling on sensor response. This device can be scaled d own and is best suited for integration with other sensors and as a bas ic transducer for biosensors.