title: Influence of fibrous encapsulation on electro-chemical properties of TiN electrodes.
abstract: The aim of this study was to investigate how the electrochemical properties of porous titanium nitride stimulation electrode are affected by fibrous encapsulation in vivo. Electrochemical impedance spectroscopy (EIS), cyclic voltammetry and voltage transient (VT) measurements were performed in vivo and in phosphate buffered saline, where the encapsulation process is absent. EIS was used as a non-invasive measurement to follow the inflammation, healing and encapsulation process. EIS showed that the healing and encapsulation process lasted 3-4 weeks. The VTs increased during the first 3-4 weeks, after which they stabilized. The charge storage capacity (CSC) decreased most during the first 3-4 weeks. The increasing VTs and decreasing CSC during the first 3-4 weeks after implantation of the in vivo electrodes seem related to healing and fibrous encapsulation. It is suggested that the charge injection pathway during the encapsulation process changes, which implies that charge injection limits are underestimated with conventional methods.
authors.affiliation: Center for Sensory-Motor Interaction, Aalborg University, Fredrik Bajersvej 7E, 9220 Aalborg, Denmark. Electronic address: suzan.meijs@gmail.com.
authors.forename: Suzan
authors.initials: S
authors.lastname: Meijs
authors.affiliation: Neurodan A/S, Aalborg, Denmark; Bang & Olufsen Medicom A/S, Struer, Denmark.
authors.forename: Morten
authors.initials: M
authors.lastname: Fjorback
authors.affiliation: Neurodan A/S, Aalborg, Denmark; Aalborg University Hospital, Aalborg, Denmark.
authors.forename: Carina
authors.initials: C
authors.lastname: Jensen
authors.affiliation: Danish Technological Institute, Århus, Denmark.
authors.forename: Søren
authors.initials: S
authors.lastname: Sørensen
authors.affiliation: Danish Technological Institute, Århus, Denmark.
authors.forename: Kristian
authors.initials: K
authors.lastname: Rechendorff
authors.affiliation: Center for Sensory-Motor Interaction, Aalborg University, Fredrik Bajersvej 7E, 9220 Aalborg, Denmark.
authors.forename: Nico J M
authors.initials: NJ
authors.lastname: Rijkhoff
mesh_terms: D002214:Capsules; D004563:Electrochemistry; D004566:Electrodes; D010710:Phosphates / Q000737:chemistry; D014025:Titanium / Q000737:chemistry*
chemical_list: D002214:Capsules; D010710:Phosphates; C041500:titanium nitride; D014025:Titanium
keywords: Electrical stimulation; Electrochemical impedance spectroscopy; Foreign body reaction; Neural stimulation electrodes; Voltage transient measurement