An in vitro model for evaluating neural stimulating electrodes.

A model for in vitro evaluation of materials for use as neural stimulation electrodes is developed. Critical areas of concern in developing an in vitro test model discussed include: selection of environment, choice of material, design of stimulating equipment, and analytical procedures used to evaluate materials response. A method of providing quantitative analysis of materials response to stimulation conditions is presented. Evaluation techniques involve the use of scanning electron microscopy, x-ray spectroscopy, atomic absorption spectrometry, and potentiographic and dielectric analysis of the test electrodes. A diagnostics matrix is presented which assigns a scale factor to quantify the relative corrosion response of the candidate materials. The corrosion response of Pt electrodes is evaluated in terms of scale factors assigned through use of the diagnostics matrix.