Disposable screen-printed biosensor for transcutaneous oxygen measurement

Transcutaneous monitoring of the partial pressure of oxygen in arterial blood eliminates the need for the extraction of blood samples. A disposable transcutaneous oxygen thick film biosensor has been designed and fabricated in-house employing screen printing methods so as to achieve cost-effective and reliable production. The oxygen sensing module of the device is based on the amperometric Clarke cell principle. A 3-electrode configuration consisting of miniature gold working and counter electrodes and a silver/silver chloride reference electrode is screen printed onto alumina substrate resulting in approximately 15 mu m thickness layers. A platinum heater element is integrated into the design to make transcutaneous measurements typically at 44\0\C. The performances of different screen printed membrane materials have been evaluated in both hydrated and dry test conditions using cyclic voltammographs and static tests where the devices are subjected to different oxygen levels. All measurements are made by a fully automated computer-controlled gas rig.