title: Mechanical deformation of thin film platinum under electrical stimulation.
abstract: Thin-film-based electrodes used to interact with nervous tissue often fail quickly if used for electrical stimulation, impairing their translation into long-term clinical applications. We initiated investigations about the mechanical load on thin-film electrodes caused by the fact of electrical stimulation. Platinum electrodes of Ø 300μm on a polyimide carrier were subjected to approximately 50 000 asymmetrical, biphasic stimulation pulses in vitro. The electrode's surface was investigated optically by means of white-light interferometry. The structural expansion for the metallic surface subjected to stimulation was measured to reach roughly 30%. The study points towards a failure mechanism of thin-films being of mechanical nature, inherent to the unavoidable electrochemical processes involved (change in lattice constants) during electrical stimulation at the electrode's surface. Based on further scientific facts, we set 3 hypotheses for the exact mechanisms involved in the failure of thin-films used for electrical stimulation, opening a new door for research and improvement of novel neuroprosthetic devices.
authors.forename: J S
authors.initials: JS
authors.lastname: Ordonez
authors.forename: L
authors.initials: L
authors.lastname: Rudmann
authors.forename: P
authors.initials: P
authors.lastname: Cvancara
authors.forename: C
authors.initials: C
authors.lastname: Bentler
authors.forename: T
authors.initials: T
authors.lastname: Stieglitz
mesh_terms: D004558:Electric Stimulation; D004599:Electric Stimulation Therapy; D004566:Electrodes; D010984:Platinum
chemical_list: D010984:Platinum