Characterization of Spinal cord stimulation electrode for chronic implant in Animal Models

A custom handcrafted electrode design is proposed here to electrically stimulate dorsal column fibers of the spinal cord in parkinsonian rats. The primary purpose of this electrode is to alleviate motor symptoms in Parkinson’s disease under the assumption that SCS might suppress the aberrant beta-frequency synchronous corticostriatal oscillations, thus restoring neural activity in the primary cortex and dorsolateral striatum to a state observed prior to the onset of spontaneous locomotion. Biocompatible materials were chosen in order to build a fully functional implantable device. Due to limitations in the epidural space of the spinal cord, platinum foil was taken as the option to make the electric contacts. Under exhausting repeated cycles of electrical stimulation, Pt foil suffers mechanical deformations on its surface. This can lead to significant changes in contact topography, thus changing the electrical impedance and biocompatibility features. It is essential to evaluate if the whole construction of the electrode is compatible with the number of stimuli to be held on parkinsonian rats in future studies in order to shed light on a systematic therapy using SCS. Electrodes were undergone wettability and electrical impedance tests before and after 48 h of electrical stimulation done in saline solution 0.9% at a frequency of 100 Hz, and 1.6 mA intensity. The stimulation had a k = 1.90, found in platinum oxidation and tissue damage. A wettability test was performed to characterize the interaction of the contact angle before and after, where there was an increase in this angle after the stimulation test. An electrical impedance test has shown that electrochemical interactions caused an increase in impedance after the stimulation period.