title: Chronic In Vivo Evaluation of PEDOT/CNT for Stable Neural Recordings.
abstract: OBJECTIVE
  Subcellular-sized chronically implanted recording electrodes have demonstrated significant improvement in single unit (SU) yield over larger recording probes. Additional work expands on this initial success by combining the subcellular fiber-like lattice structures with the design space versatility of silicon microfabrication to further improve the signal-to-noise ratio, density of electrodes, and stability of recorded units over months to years. However, ultrasmall microelectrodes present very high impedance, which must be lowered for SU recordings. While poly(3,4-ethylenedioxythiophene) (PEDOT) doped with polystyrene sulfonate (PSS) coating have demonstrated great success in acute to early-chronic studies for lowering the electrode impedance, concern exists over long-term stability. Here, we demonstrate a new blend of PEDOT doped with carboxyl functionalized multiwalled carbon nanotubes (CNTs), which shows dramatic improvement over the traditional PEDOT/PSS formula.
  
  
  METHODS
  Lattice style subcellular electrode arrays were fabricated using previously established method. PEDOT was polymerized with carboxylic acid functionalized carbon nanotubes onto high-impedance (8.0 ± 0.1 MΩ: M ± S.E.) 250-μm(2) gold recording sites.
  
  
  RESULTS
  PEDOT/CNT-coated subcellular electrodes demonstrated significant improvement in chronic spike recording stability over four months compared to PEDOT/PSS recording sites.
  
  
  CONCLUSIONS
  These results demonstrate great promise for subcellular-sized recording and stimulation electrodes and long-term stability.
  
  
  CONCLUSIONS
  This project uses leading-edge biomaterials to develop chronic neural probes that are small (subcellular) with excellent electrical properties for stable long-term recordings. High-density ultrasmall electrodes combined with advanced electrode surface modification are likely to make significant contributions to the development of long-term (permanent), high quality, and selective neural interfaces.
authors.forename: Takashi D Y
authors.initials: TD
authors.lastname: Kozai
authors.forename: Kasey
authors.initials: K
authors.lastname: Catt
authors.forename: Zhanhong
authors.initials: Z
authors.lastname: Du
authors.forename: Kyounghwan
authors.initials: K
authors.lastname: Na
authors.forename: Onnop
authors.initials: O
authors.lastname: Srivannavit
authors.forename: Razi-Ul M
authors.initials: RU
authors.lastname: Haque
authors.forename: John
authors.initials: J
authors.lastname: Seymour
authors.forename: Kensall D
authors.initials: KD
authors.lastname: Wise
authors.forename: Euisik
authors.initials: E
authors.lastname: Yoon
authors.forename: Xinyan Tracy
authors.initials: XT
authors.lastname: Cui
mesh_terms: D000818:Animals; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000737:chemistry*; D004567:Electrodes, Implanted; D004867:Equipment Design; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D037742:Nanotubes, Carbon / Q000737:chemistry*; D058117:Neural Prostheses; D009482:Neurophysiology / Q000379:methods*; D011108:Polymers / Q000737:chemistry*
chemical_list: D019086:Bridged Bicyclo Compounds, Heterocyclic; D037742:Nanotubes, Carbon; D011108:Polymers; C121383:poly(3,4-ethylene dioxythiophene)