Ultrathin organic films for biocompatible low-impedance pacemaker electrodes

In an attempt to enhance biocompatibility ultrathin membranes were synthesized onto iridium pacemaker electrodes. For this purpose a versatile multistep reaction scheme was devised. The coverage and electrical properties of the membranes thus fabricated were determined by ESCA, FTIR-ATR and AC-impedance measurements. Although coverage is complete, the electrode impedance remains low indicating the deposition of a very homogeneous thin membrane. Since the electrodes exhibit a fractal surface structure physisorption of a crosslinked polysiloxane network from trichlorosilane yields excellent membrane stability.