title: Influence of implantation on the electrochemical properties of smooth and porous TiN coatings for stimulation electrodes.
abstract: OBJECTIVE
  To determine whether changes in electrochemical properties of porous titanium nitride (TiN) electrodes as a function of time after implantation are different from those of smooth TiN electrodes.
  
  
  METHODS
  Eight smooth and 8 porous TiN coated electrodes were implanted in 8 rats. Before implantation, voltage transients, cyclic voltammograms and impedance spectra were recorded in phosphate buffered saline (PBS). After implantation, these measurements were done weekly to investigate how smooth and porous electrodes were affected by implantation.
  
  
  RESULTS
  The electrode capacitance of the porous TiN electrodes decreased more than the capacitance of the smooth electrodes due to acute implantation under fast measurement conditions (such as stimulation pulses). This indicates that protein adhesion presents a greater diffusion limitation for counter-ions for the porous than for the smooth electrodes. The changes in electrochemical properties during the implanted period were similar for smooth and porous TiN electrodes, indicating that cell adhesion poses a similar diffusion limitation for smooth and porous electrodes.
  
  
  CONCLUSIONS
  This knowledge can be used to optimize the porous structure of the TiN film, so that the effect of protein adhesion on the electrochemical properties is diminished. Alternatively, an additional coating could be applied on the porous TiN that would prevent or minimize protein adhesion.
authors: Center for Sensory-Motor Interaction, Department of Health, Science and Technology, Aalborg University, Fredrik Bajersvej 7D, Denmark.
authors: S
authors: S
authors: Meijs
authors: C
authors: C
authors: Sørensen
authors: S
authors: S
authors: Sørensen
authors: K
authors: K
authors: Rechendorff
authors: M
authors: M
authors: Fjorback
authors: N J M
authors: NJ
authors: Rijkhoff
mesh_terms: D000818:Animals; D025802:Electric Capacitance; D004563:Electrochemistry; D004567:Electrodes, Implanted; D008297:Male; D016062:Porosity / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D040521:Subcutaneous Tissue / Q000737:chemistry* / Q000187:drug effects; D013499:Surface Properties / Q000187:drug effects; D014025:Titanium / Q000008:administration & dosage / Q000737:chemistry*
chemical_list: C041500:titanium nitride; D014025:Titanium