Michael F. Nichols

The adhesion of glow-discharge polymers, Silastic and Parylene to implantable platinum electrodes: results of tensile pull tests after exposure to isotonic sodium chloride

Thin organic coatings commonly are used for insulating microelectrodes and electronic packages designed for implant applications. The adherence of these coatings to the underlying substrates is a key parameter in their selection for various devices. Instron pull tests were performed on glow-discharge polymerized monomers, Parylene-N, medical-grade Silastic and various epoxies. The application of a thin coating of glow-discharge polymerized methane under a thicker Parylene-N coating improved the adhesion of the latter to the underlying substrate in isotonic sodium chloride solution and during accelerated testing conditions done by boiling.

Cyclic Voltammetry for the Study of Polymer Film Adhesion to Platinum Neurological Electrodes

Abstract Many epoxy and polymeric coatings, with a broad spectrum of bulk and surface properties, are available for microelectrode insulators in neurophysiology. One of the premier properties of a biomaterial must be its ability to adhere to the underlying substrate. The technique of cyclic voltammetry has been applied to neurological electrodes to compare the adhesion of various insulating films. We found that this technique was advantageous over conventional ones (i.e. pull tests) in that we could observe the synergistic effects of water, ions, and electric fields.

Glow Discharge Polymer Coated Oxygen Sensors

The need to measure reliably and accurately oxygen concentration in biological media is often crucial. Presently used commercially available and laboratory fabricated systems usually utilize polarographic sensors to measure oxygen partial pressure in aqueous media. These sensors use a noble metal (platinum or gold) cathode connected to a source of electrons, (commonly a battery) and are referenced to a suitable anode such as Ag/AgC1 to complete the circuit. Many methods have been used to improve sensor drift, sensitivity, and response time by permuting cathode geometry, construction details, membrane type and thickness, and electronic correction techniques. For a review of these methods the interested reader is referred to (1,2).

Performance of implanted biogalvanic pacemakers.

Seventeen unipolar cardiac pacemakers powered by hybrid biogalvanic cells were implanted in dogs. Long term clinical effects and electrical performance in vivo of the generators were investigated. The biogalvanic cells were designed to provide 50 years of generator operation.