Biomedical applications
The pH ISFET chip is very suitable to be built-in in a catheter as has been done in the period 1975-1985 by the pacemaker company Cordis in Roden, the Netherlands. The reference electrode was made in the tip of the catheter which contained a polyHEMA plug, a KCl gel and a Ag/AgCl electrode. The Al2O3 ISFET was mounted behind a side window near the tip of the 6F catheter