Covalent surface chemical modification of electrodes for cardiac pacing applications

We report the covalent surface modification of active-fixation pacemaker electrodes with butanethiol or dodecanethiol self-assembled monolayers (SAMs) using a platinum or gold metal-thiolate bond (i.e., changing the chemical identity of the exposed metal electrode from metal to organic) in such fashion that (a) the surface is organic in functionality with lipophilic physicochemical characteristics, (b) a possible degradation product is gold (I)-alkanethiolate with putative anti-inflammatory actions, and (c) current density/electric field strength is increased. Superior acute and chronic pacing performance with dodecanethiol-modified, gold-coated, platinum-iridium alloy pacemaker electrodes was observed with inferential evidence of reduced inflammation and scar. This approach may have applicability in other areas of bioelectrodes with practical applications in clinical cardiology, surgery, neuroscience, and subcutaneous sensors. (C) 2000 John wiley and Sons, Inc.