Fabrication of pH-sensitive implantable electrode by thick film hybrid technology.

We report preliminary results of our experiments directed at fabricating pH-sensitive electrodes suitable for in vivo use by means of thick film screening techniques. Our results show that glass membranes of suitable thickness and possessing nearly theoretical sensitivity to pH can be fabricated by this process. A hybrid electrode structure permits the incorporation of a source follower FET amplifier directly adjacent to the pH membrane, significantly reducing response time and noise pick-up. Extension of the basic electrode structure to accommodate membranes sensitive to other ions is discussed.