ON THE CHEMICAL MODIFICATION OF PACEMAKER ELECTRODES AND PATTERNED SURFACE FUNCTIONALIZATION OF PLANAR SUBSTRATES

We report on experiments towards the chemical modification of metal el ectrodes in order to enhance biocompatibility or improve cell adhesion properties. In the first example pacemaker electrodes were modified w ith a thin polysiloxane network which allowed for further derivatizati on with a poly(ethylene glycol) layer. The primary goal was to suppres s inflammatory response of tissue after implantation of electrodes. FT IR, ESCA and a.c.-impedance spectroscopy show the integrity of the ult rathin membrane. No significant reduction of the electrode capacitance was observed, providing further proof for the deposition of a homogen eously thin membrane. The second example deals with the patterned chem ical modification of planar surfaces. The goal was to eventually effec t selective adhesion of electrosensitive cells above microelectrodes f or stimulation and/or recording. First results demonstrate the compati bility of monolayer deposition techniques with common photolithography . It is thus possible to create surfaces with patterned chemical funct ionality. A gas-phase silylation process was developed in order to con trol more precisely surface hydration and reaction parameters than is possible with common solution-based silylation procedures. (C) 1997 El sevier Science Limited.