Multichannel ISFET catheter for temporal and spatial pH variation studies in the stomach over 24 hours

A four channel multiple sensor based on ISFETs has been developed for medical research in gastroenterology. The ISFETs are mounted in two groups separated by 10 cm and placed as close as possible in each group. New solutions for the electrical connections by kapton tape and for the disposition of the ISFET have been developed. An increased lifetime of the sensors is achieved by a silanization procedure which promotes adhesion between the ISFET surface and the encapsulating epoxide. The lifetime has been tested for Si3N4 and Al2O3 ISFETs. The realized sensors have been tested in clinical conditions in a university hospital and demonstrate accurate and interesting results as well as being comfortable to use.