Covalent surface chemical modification of electrodes for cardiac pacing applications

We report the covalent surface modification of active-fixation pacemaker el ectrodes 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 fash ion that (a) the surface is organic in functionality with lipophilic physic ochemical characteristics, (b) a possible degradation product is gold (I)-a lkanethiolate with putative anti-inflammatory actions, and (c) current dens ity/electric field strength is increased. Superior acute and chronic pacing performance with dodecanethiol-modified, gold-coated, platinum-iridium all oy pacemaker electrodes was observed with inferential evidence of reduced i nflammation and scar. This approach may have applicability in other areas o f bioelectrodes with practical applications in clinical cardiology, surgery , neuroscience, and subcutaneous sensors. (C) 2000 John Wiley & Sons, Inc. J Biomed Mater Res, 51, 209-215, 2000.