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Cited by 57Neuroscience and Neural EngineeringConducting polymers and applicationsVagus Nerve Stimulation Research

Flexible Nerve Stimulation Electrode With Iridium Oxide Sputtered on Liquid Crystal Polymer

Open access
Wang, K., Chung-Chiun Liu, Durand, D.M.·2009·IEEE Transactions on Biomedical Engineering
DOI 10.1109/tbme.2008.926691PMC PMC2738844
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Abstract

Current electrode designs require flexible substrates that absorb little moisture and provide large charge injection capability. Sputtered iridium oxide films have superior charge injection capabilities versus noble metals and can adhere to various substrates. Liquid crystal polymers (LCPs) have very little water absorption compared to other flexible substrates. Therefore, the combination of sputtered iridium oxide film on LCP substrate was studied using 50 Hz, 100 micros duration, and 10 mA biphasic current waveforms for 700 h at 67 degrees C in bicarbonate buffer saline. Scanning electron micrograph analysis showed no delamination and approximately 1% of electrode material was lost to the bicarbonate buffer. The charge injection limit and the cathodic charge storage capacity within the water window were 4.6 +/- 1.0 and 31.5 +/-6.6 mC/cm2, respectively. Additional electrochemical analysis revealed significant charge imbalance attributed to oxygen reduction within the water window. These results, along with the flexible, chemically inert, and biocompatible substrate, indicate that sputtered iridium oxide films on LCP could become the method of choice for flexible substrate nerve electrodes.

AI snapshot

Written from the paper’s full text.

TL;DR

Reactively sputtered iridium oxide on liquid crystal polymer survived long-term in vitro stimulation without delamination and showed high charge injection, but exhibited significant charge imbalance under oxygen/carbon dioxide conditions attributed to oxygen reduction. The LCP lamination process damaged the iridium oxide films, so non-laminated epoxy-insulated electrodes were used for further testing.

Key findings

  • After ~700 hours of stimulation at 67°C with 10 mA, 100 μs, 50 Hz biphasic waveforms, SEM showed no delamination and approximately 1% of electrode material was lost to bicarbonate buffer (0.051 μg iridium per electrode), equivalent to eight months at 37°C.
  • Charge injection limit was 4.6 ± 1.0 mC/cm²; cathodic charge storage capacity was 31.5 ± 6.6 mC/cm² under 100% N₂ and 33.7 ± 10.1 mC/cm² under O₂/CO₂.
  • Under O₂/CO₂, net average charge loss was −3.0 ± 1.1 mC/cm²·cycle, versus a net charge gain of 0.43 ± 0.38 mC/cm²·cycle under N₂; the water window narrowed to −0.3 to 0.6 V SCE under O₂/CO₂ versus −0.64 to 0.75 V SCE under N₂.
  • Laminated electrodes showed cracks in the iridium oxide, sometimes traversing traces and preventing electrical continuity; non-laminated epoxy-insulated electrodes were used thereafter.

Methods

  • Reactively sputtered iridium oxide films (2.03 μm) on 50 μm LCP with a 2 nm titanium adhesion layer; four sets of 1 mm² stimulation pads, traces, and bonding pads were fabricated, with half laminated with 50 μm LCP and half epoxy-insulated.
  • Electrochemical analysis used cyclic voltammetry at 50 mV/s, impedance spectroscopy, and charge injection limit testing with 5 ms capacitively coupled biphasic waveforms; long-term testing stimulated eight electrodes in bicarbonate buffer at 67°C for four weeks (equivalent to eight months at 37°C) with 10 mA, 100 μs, 50 Hz, plus four unstimulated controls.
  • Post-test analysis included SEM imaging and inductively coupled plasma mass spectroscopy (ICP-MS) for iridium in solution.

Limitations

  • Stated: the LCP lamination process at around 300°C damaged the thin metal films, interrupting iridium oxide continuity; charge imbalance under O₂/CO₂ suggests oxygen reduction and potentially harmful species, and further studies are needed to confirm oxygen reduction, tissue damage, and whether electrodes must be recharacterized to a −0.3 V SCE charge injection limit.
  • Evident: all testing was in vitro with accelerated soak conditions, with no in vivo validation; charge injection limit was measured only under O₂/CO₂; the laminated electrode design was not viable in the tested form; CSCc varied across electrodes.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1109/tbme.2008.926691

Cites

36 of 36 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 55 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    Additional electrochemical analysis revealed significant charge imbalance within the water window.

    “Additional electrochemical analysis revealed significant charge imbalance attributed to oxygen reduction within the water window.”
    Quote in the paperNot a substantial claim
  • Findingown data

    The charge injection limit within the water window was 4.6 +/− 1.0 mC/cm2.

    “The charge injection limit and the cathodic charge storage capacity within the water window were 4.6 +/− 1.0mC/cm2 and 31.5 +/− 6.6mC/cm2 respectively.”
    Quote in the paperSubstantial claim
  • Findingown data

    Approximately 1% of electrode material was lost to the bicarbonate buffer.

    “Scanning electron micrograph (SEM) analysis showed no delamination and approximately 1% of electrode material was lost to the bicarbonate buffer.”
    Quote in the paperSubstantial claim
  • Findingown data

    The cathodic charge storage capacity within the water window was 31.5 +/− 6.6 mC/cm2.

    “The charge injection limit and the cathodic charge storage capacity within the water window were 4.6 +/− 1.0mC/cm2 and 31.5 +/− 6.6mC/cm2 respectively.”
    Quote in the paperSubstantial claim
  • Findingown data

    This voltage range was significantly smaller compared to the −0.6V to 0.7V SCE voltage range under 100% nitrogen gas.

    “This voltage range was significantly smaller compared to the −0.6V to 0.7V SCE voltage range under 100% nitrogen gas.”
    Quote in the paperSubstantial claim
  • The quote only partly states this claim. 1
  • May combine two claims. 22
  • Classified as probably not a substantial claim. 14

  • The quote only partly states this claim.

    Findingown data

    SEM analysis showed no delamination of the sputtered iridium oxide on LCP electrodes after long-term stimulation and accelerated soak.

    “Scanning electron micrograph (SEM) analysis showed no delamination and approximately 1% of electrode material was lost to the bicarbonate buffer.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    At lower frequencies, the impedance increased and was strongly dependent on frequency.

    “At lower frequencies, the impedance increased and was strongly dependent on frequency.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Some laminated electrodes showed cracks traversing the traces prevented electrical continuity.

    “Some laminated electrodes showed cracks traversing the traces prevented electrical continuity.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    The charge storage capacity of the iridium oxide electrodes here was observed to be larger than the charge storage capacity obtained with activated iridium oxide films reported by Agnew et al [4] and sputtered iridium oxide films reported by Cogan et al. [1].

    “The charge storage capacity of the iridium oxide electrodes here was observed to be larger than the charge storage capacity obtained with activated iridium oxide films reported by Agnew et al [4] and sputtered iridium oxide films reported by Cogan et al. [1]”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [4] Wichmann T DeLong MR Deep Brain Stimulation for Neurologic and Neuropsychiatric Disorders Neuron 52 197 204 October 2006 17015236 source

      Not checked in the free run.

    • cites [1] Lyons GM Sinkjaer T Burridge JH Wilcox DJ A Review on Portable FES-based Neural Orthoses for the Correction of Drop Foot IEEE Transactions on Rehabilitation Engineering 10 260 279 2002 12611364 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Findingown data

    Visual inspection of the electrode under a light microscope showed an iridescent grey color to the electrode with no visible cracking in the film.

    “Visual inspection of the electrode under a light microscope showed an iridescent grey color to the electrode with no visible cracking in the film.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Fitting the Bode plot with a constant phase element model with series resistance (Rs + [(j ω)P C]−1) revealed an Rs of 2.72 Ω/cm2, a C of 6.55mF/cm2, and exponent P of 0.8 with all variables having errors of less than 2%.

    “However, fitting the Bode plot with a constant phase element model with series resistance (Rs + [(j ω)P C]−1) revealed an Rs of 2.72 Ω/cm2, a C of 6.55mF/cm2, and exponent P of 0.8 with all variables having errors of less than 2%.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The post-cathodic working electrode voltages were plotted with respect to the amount of charge injected into the electrode, and a linear relationship was observed (R2 = 0.96).

    “The post-cathodic working electrode voltages were plotted with respect to the amount of charge injected into the electrode, and a linear relationship was observed (R2 = 0.96) (Fig. 4b).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Additional voltage ramps sweeping from −0.645V to 0.755V SCE (−0.6V to 0.8V Ag|AgCl) that has been consistently used in literature for electrode characterization also yielded minimal charge loss, indicating that the water window was −0.64V to 0.75V SCE.

    “Additional voltage ramps sweeping from −0.645V to 0.755V SCE (−0.6V to 0.8V Ag|AgCl) that has been consistently used in literature for electrode characterization also yielded minimal charge loss, indicating that the water window was −0.64V to 0.75V SCE.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingnone given

    Despite the large CSCc variation among the electrodes, the variability of the CSCc of each individual electrode was very small.

    “Despite the large CSCc variation among the electrodes, the variability of the CSCc of each individual electrode was very small.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Under oxygen and carbon dioxide conditions, only two peaks were observed: an oxidation peak at +0.45 V SCE and a reduction peak at −0.4 V SCE.

    “Under oxygen and carbon dioxide conditions, only two peaks were observed: an oxidation peak at +0.45 V SCE and a reduction peak at −0.4 V SCE (arrows, Fig. 3a).”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    The variation of the CSCc for each individual electrode was also observed to be small under oxygen/carbon dioxide conditions.

    “The variation of the CSCc for each individual electrode was also observed to be small under oxygen/carbon dioxide conditions.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingnone given

    The peaks were not as well defined compared to the CVs of activated iridium oxide in et al [1].

    “These peaks were not as well defined compared to the CVs of activated iridium oxide in et al [1].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [1] Lyons GM Sinkjaer T Burridge JH Wilcox DJ A Review on Portable FES-based Neural Orthoses for the Correction of Drop Foot IEEE Transactions on Rehabilitation Engineering 10 260 279 2002 12611364 source

      Not checked in the free run.

  • May combine two claims.

    Findingown data

    The impedances were frequency-independent, between 290Ω and 500Ω (average |Z| = 390 +/− 80Ω/cm2) (N = 7), for frequencies higher than 1kHz.

    “The impedances were frequency-independent, between 290Ω and 500Ω (average |Z| = 390 +/− 80Ω/cm2) (N = 7), for frequencies higher than 1kHz.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Cyclic voltammetry analysis showed stable CV traces of the iridium oxide electrodes but with an additional oxidation peak at 0.1V SCE appearing approximately halfway into the stimulation protocol and continuing to grow throughout the remainder of the stimulation and soak protocol.

    “Cyclic voltammetry analysis showed stable CV traces of the iridium oxide electrodes but with an additional oxidation peak at 0.1V SCE appearing approximately halfway into the stimulation protocol and continuing to grow throughout the remainder of the stimulation and soak protocol.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingcitation

    The frequency dependence of the sputtered iridium oxide film impedance was also similar to other activated and electrodeposited iridium oxide films [3].

    “The frequency dependence of the sputtered iridium oxide film impedance was also similar to other activated and electrodeposited iridium oxide films [3].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [3] van Balken MR Vergunst H Bemelmans BL The Use of Electrical Devices for the Treatment of Bladder Dysfunction: a review of methods The Journal of Urology 172 846 851 2004 15310981

      Not checked in the free run.

  • May combine two claims.

    Findingown data

    The voltage excursion of the working electrode, as defined in Fig. 4a, seemed to vary greatly during the course of the stimulation procedure, averaging 0.125V with a standard deviation of 0.050V but did not drift with time.

    “The voltage excursion of the working electrode, as defined in Fig. 4a, seemed to vary greatly during the course of the stimulation procedure, averaging 0.125V with a standard deviation of 0.050V but did not drift with time.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Electrochemical testing of the sputtered iridium oxide films on liquid crystal polymer showed that the cathodic charge storage capacity and the injectable charge limit were higher than those obtained for activated and electrodeposited iridium oxide films [4] [5] [6] [7].

    “Electrochemical testing of the sputtered iridium oxide films on liquid crystal polymer showed that the cathodic charge storage capacity and the injectable charge limit were higher than those obtained for activated and electrodeposited iridium oxide films [4] [5] [6] [7].”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [4] Wichmann T DeLong MR Deep Brain Stimulation for Neurologic and Neuropsychiatric Disorders Neuron 52 197 204 October 2006 17015236 source

      Not checked in the free run.

    • cites [5] Theodore WH Brain Stimulation for Epilepsy Nature Clinical Practice Neurology 1 64 65 2005 16932495 source

      Not checked in the free run.

    • cites [6] Wang GJ Yang J Volkow ND Telang F Ma Y Zhu W Wong CT Tomasi D Thanos PK Fowler JS Gastric stimulation in obese subjects activates the hippocampus and other regions involved in brain reward circuitry Proceedings of the National Academy of Sciences of the United States 103 15641 15645 2006 PMC1592230 17023542 source

      Not checked in the free run.

  • May combine two claims.

    Findingown data

    Impedance testing of the sputtered iridium oxide films also revealed Bode plots with slightly higher impedances compared the sputtered iridium oxide films reported by Cogan et al. [1] and Slavcheva et al [2], but lower compared to electrodeposited and activated iridium oxide films [3].

    “Impedance testing of the sputtered iridium oxide films also revealed Bode plots with slightly higher impedances compared the sputtered iridium oxide films reported by Cogan et al. [1] and Slavcheva et al [2], but lower compared to electrodeposited and activated iridium oxide films [3].”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites [1] Lyons GM Sinkjaer T Burridge JH Wilcox DJ A Review on Portable FES-based Neural Orthoses for the Correction of Drop Foot IEEE Transactions on Rehabilitation Engineering 10 260 279 2002 12611364 source

      Not checked in the free run.

    • cites [2] Degnan GG Wind TC Jones EV Edlich RF Functional Electrical Stimulation in Tetraplegic Patients to Restore Hand Function Journal of Long-term effects of Medical Implants 12 175 188 2002 12545943 source

      Not checked in the free run.

    • cites [3] van Balken MR Vergunst H Bemelmans BL The Use of Electrical Devices for the Treatment of Bladder Dysfunction: a review of methods The Journal of Urology 172 846 851 2004 15310981 source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Sputtered iridium oxide films are mechanically stable and can resist corrosion and degradation.

    “In contrast, sputtered iridium oxide films have been shown to be mechanically stable and can resist corrosion and degradation [11].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [11] Cogan SF Plante TD Ehrlich J Sputtered iridium oxide films (SIROFs) for low-impedance neural stimulation and recording electrodes 26th Annual International Conference of the IEEE EMBS 2004 4153 4156 PMC2709748 17271216 source

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

    Iridium oxide has been used to increase the amount of total charge that can be delivered for electrical stimulation.

    “Iridium oxide has been used to increase the amount of total charge that can be delivered for electrical stimulation [9].”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites [9] Agnew WF McCreery DB Neural Prostheses: Fundamental Studies Englewood Cliffs, NJ Prentice Hall 1990

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    For iridium oxide films made from sputtered iridium metal, charge injection limits have been reported to be 4-6 mC/cm2.

    “For iridium oxide films made from sputtered iridium metal, charge injection limits have been reported to be 4–6mC/cm2 [10].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [10] Weiland JD Anderson DJ Humayun MS In Vitro Electrical Properties for Iridium Oxide Versus Titanium Nitride Stimulating Electrodes IEEE Transactions on Neural Systems and Rehabilitation Engineering 40 1574 1579 2002 12549739 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Sputtered iridium oxide films have been deposited onto platinum and silicon substrates.

    “Sputtered iridium oxide films have been deposited onto platinum [11] and silicon [16] substrates.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [11] Cogan SF Plante TD Ehrlich J Sputtered iridium oxide films (SIROFs) for low-impedance neural stimulation and recording electrodes 26th Annual International Conference of the IEEE EMBS 2004 4153 4156 PMC2709748 17271216 source

      Not checked in the free run.

    • cites [16] Tanghe SJ Najafi K Wise KD A Planar IrO Multichannel Stimulating Electrode for Use in Neural Prostheses Sensors and Actuators, B1 1 464 467 1990

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Premisecitation

    Charge injection limits for iridium oxide films made from iridium wire are +/− 2 mC/cm2 for anodic-first and −/+ 1 mC/cm2 for cathodic-first current waveforms.

    “Charge injection limits for iridium oxide films made from iridium wire have been reported to be +/− 2 mC/cm2 and −/+ 1 mC/cm2 for anodic-first and cathodic-first current waveforms, respectively and are significantly higher than those reported for stainless steel or platinum [9].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [9] Agnew WF McCreery DB Neural Prostheses: Fundamental Studies Englewood Cliffs, NJ Prentice Hall 1990

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Charge injection limits for iridium oxide films made from iridium wire are significantly higher than those reported for stainless steel or platinum.

    “Charge injection limits for iridium oxide films made from iridium wire have been reported to be +/− 2 mC/cm2 and −/+ 1 mC/cm2 for anodic-first and cathodic-first current waveforms, respectively and are significantly higher than those reported for stainless steel or platinum [9].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [9] Agnew WF McCreery DB Neural Prostheses: Fundamental Studies Englewood Cliffs, NJ Prentice Hall 1990

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Premisecitation

    Activated iridium oxide films have uneven growth of the oxide layer that introduces strain and can result in a tendency to delaminate from the underlying iridium metal.

    “For activated iridium oxide films, uneven growth of the oxide layer introduces strain in the oxide layer and can result in the tendency for the activated iridium oxide film to delaminate from the underlying iridium metal [12] [13].”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [12] Slavcheva E Vitushinsky R Mokwa W Schnakenberg U Sputtered Iridium Oxide Films as Charge Injection Material for Functional Electrostimulation Journal of The Electrochemical Society 151 E226 E237 2004

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites [13] Cogan SF Guzelian AA Agnew WF Yuen TGH McCreery DB Over-pulsing degrades activated iridium oxide films used for intracortical neural stimulation Journal of Neuroscience Methods 137 141 150 2004 15262054 source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Electrodeposited iridium oxide adheres poorly with its underlying substrate, resulting in a tendency to delaminate while under operation, which shortens the electrode lifespan.

    “Electrodeposited iridium oxide has been reported to adhere poorly with its underlying substrate, resulting in a tendency, to delaminate while under operation, which shortens the electrode lifespan [14] [15].”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [14] Marzouk SAM Improved Electrodeposited Iridium Oxide pH Sensor Fabricated on Etched Titanium Substrates Analytical Chemistry 75 1258 1266 February 19 2003 12659184 source

      Not checked in the free run.

    • cites [15] Mailley SC Hyland M Mailley P McLaughlin JM McAdams ET Electrochemical and Structural Characterizations of Electrodeposited Iridium Oxide Thin-film Electrodes Applied to Neurostimulating Electrical Signal Materials Science and Engineering 21 167 175 2002 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Polyimide is a biocompatible polymer.

    “Polyimide, a biocompatible polymer [17] [18], has been a substrate of choice for many electrodes with electro-deposited iridium metal layers and iridium films [19] [20].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [17] Metz S Bertsch A Bertrand D Renauld P Flexible Polyimide probes with microelectrodes and embedded microfluidic channels for simultaneous drug delivery and multi-channel monitoring of bioelectric activity Biosensors and Bioelectronics 19 1309 1318 2004 15046764 source

      Not checked in the free run.

    • cites [18] Stieglitz T Beutel H Schuettler M Meyer JU Micromachined, Polyimide-Based Devices for Flexible Neural Interfaces Biomedical Microdevices 2 283 294 2000

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Similar multiple peaks had been reported by Cogan et al. [1] and Slavcheva et al. [2].

    “Similar multiple peaks had been reported by Cogan et al. [1] and Slavcheva et al. [2].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [1] Lyons GM Sinkjaer T Burridge JH Wilcox DJ A Review on Portable FES-based Neural Orthoses for the Correction of Drop Foot IEEE Transactions on Rehabilitation Engineering 10 260 279 2002 12611364 source

      Not checked in the free run.

    • cites [2] Degnan GG Wind TC Jones EV Edlich RF Functional Electrical Stimulation in Tetraplegic Patients to Restore Hand Function Journal of Long-term effects of Medical Implants 12 175 188 2002 12545943 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Polyimide has been a substrate of choice for many electrodes with electro-deposited iridium metal layers and iridium films.

    “Polyimide, a biocompatible polymer [17] [18], has been a substrate of choice for many electrodes with electro-deposited iridium metal layers and iridium films [19] [20].”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites [19] Meyer RD Cogan SF Nguyen TH Rauh RD Electrodeposited Iridium Oxide for Neural Stimulation and Recording Electrodes IEEE Transactions on Neural Systems and Rehabilitation Engineering 9 2 11 March 2001 11482359 source

      Not checked in the free run.

    • cites [20] Stieglitz T Beutel H Keller R Schuettler M Meyer J-U Flexible, Polyimide-Based Neural Interfaces Seventh International Conference on Microelectronics for Neural, Fuzzy and Bio-Inspired Systems 1999

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Premisecitation

    LCP is a biocompatible and flexible substrate.

    “Liquid crystal polymer (LCP) is also biocompatible and flexible substrate [22] [23] [24].”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites [22] Edell DJ Farrell B Implantable devices having a liquid crystal polymer substrate U. S. P. a. T. Office United States of America 2003

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites [23] Lee CJ Oh SJ Song JK Kim SJ Neural signal recording using microelectrode arrays fabricated on liquid crystal polymer material Materials Science and Engineering: C 24 265 268 January 2004

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites [24] McCamley MK Artenstein AW Crawford GP Woltman SJ Crawford GP Jay GD Liquid Crystal Biosensors: A New Approach to Medical Diagnostic Devices Liquid Crystals: Frontiers in Biomedical Applications Hackensack, NJ World Scientific 2007

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationnone given

    The oxidation peak at around 0.1V SCE arose from the rearrangement of the iridium oxide lattice structure.

    “We postulate that this peak arose from the rearrangement of the iridium oxide lattice structure.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationown data

    The sputtered iridium oxide film on LCP was robust and could provide a good solution for stimulation electrodes that require a flexible substrate and large charge injection capability.

    “Finally, the sputtered iridium oxide film on LCP was robust and could provide a good solution for stimulation electrodes that require a flexible substrate and large charge injection capability [12] [13].”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites [12] Slavcheva E Vitushinsky R Mokwa W Schnakenberg U Sputtered Iridium Oxide Films as Charge Injection Material for Functional Electrostimulation Journal of The Electrochemical Society 151 E226 E237 2004

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites [13] Cogan SF Guzelian AA Agnew WF Yuen TGH McCreery DB Over-pulsing degrades activated iridium oxide films used for intracortical neural stimulation Journal of Neuroscience Methods 137 141 150 2004 15262054 source

      Not checked in the free run.

  • May combine two claims.

    Interpretationown data

    The LCP substrate itself was observed to be rough and could have contributed to both the amorphous and spongy film structure and the lack of delamination.

    “The LCP substrate itself was observed to be rough and could have contributed to both the amorphous and spongy film structure and the lack of delamination.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Premisecitation

    Discrepancies in CVs have been observed with exposure of different faces of the platinum crystal lattice in solution.

    “Such discrepancies have been observed in CVs involving the exposure of different faces of the platinum crystal lattice in solution [9].”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites [9] Agnew WF McCreery DB Neural Prostheses: Fundamental Studies Englewood Cliffs, NJ Prentice Hall 1990

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Interpretationreasoning

    Operating the electrode at voltages that avoid charge imbalance allows the charge injected into the electrode to be recovered and minimizes the possibility of generating harmful species in biological tissue.

    “By operating the electrode at voltages that avoid charge imbalance, the charge injected into the electrode can be recovered and the possibility of generating harmful species in biological tissue can be minimized.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationreasoning

    The electrochemical properties of the electrode should not change with changes to the fabrication process, since the electrochemistry occurs at the iridium oxide.

    “However, the electrochemical properties of the electrode should not change, since the electrochemistry occurs at the iridium oxide.”
    Quote in the paperNot a substantial claim
36 of 36

  • The paper relies on this without support.

    LCP is chemically inert, facilitating long-term biological implantation.

    “LCP is also chemically inert facilitating long-term biological implantation.”

  • The paper relies on this without support.

    10mA is ten times higher than the normal amplitude used for peripheral nerve electrodes.

    “The 10mA current amplitude was chosen since preliminary working electrode voltage measurements indicated that the working electrode was operating within the water window, and 10mA is ten times higher than the normal amplitude used for peripheral nerve electrodes.”

  • The paper relies on this without support.

    The accelerated soak and stimulation protocol at 67°C for approximately 700 hours is equivalent to eight months at human body temperature.

    “equivalent stimulation and soak time of eight months at human body temperature”

  • The paper relies on this without support.

    Charge imbalance is associated with net charge consumption for or output from electrochemical reactions that are not reversed.

    “Charge imbalance is associated with net charge consumption for or output from electrochemical reactions that are not reversed.”
4 of 4

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • Iridium oxide coating is corrosion resistant and exhibits, in general, good biocompatibility and higher charge delivery capacity, but its exact properties depend greatly on the fabrication method, which affects the stability of the coating.

    “Iridium oxide (IrO2) coating is corrosion resistant and exhibits, in general, good biocompatibility and higher charge delivery capacity (Wang et al. 2009). Nevertheless, its exact properties depend greatly on the fabrication method – activated, sputtered and electrodeposited variants have been reported – which, in turn, affects the stability of the coating.”

    From Realizing flexible bioelectronic medicines for accessing the peripheral nerves – technology considerations (2018) · cites this paper as Wang et al. 2009

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Cogan is cited as reference 1, which lists different authors

    Minor

    The cited reference [1] is by Lyons and colleagues, not Cogan. This makes the attribution of the reported electrochemical peaks inconsistent with the paper's reference list.

1 of 1

Cites

Flagged first, then by citations

Research works printed but not linked: 3

  1. edell, 2003, implantable devices having a liquid crystal polymer substrate, U S Patent 6 643552
  2. mccamley, 2007, Proc Liquid Crystals Frontiers in Biomedical Applications
  3. hayden, 2002, new liquid crystal polymer flex circuits to meet demanding reliability and end-use applications, Int Conf Adv Packag Syst

Cited by

Sorted by citations

Related

Authors
Wang, K., Liu, C.-C., & Durand, D. M.
Affiliations
Case Western Reserve University (US)
ORCID
Durand, D.M.
Venue
IEEE Transactions on Biomedical Engineering
Publisher
Institute of Electrical and Electronics Engineers (IEEE)
Published
2009-01
Volume
56
Issue
1
Pages
6-14
ISSN
  • 0018-9294 (ISSN-L)
  • 1558-2531
DOI
10.1109/tbme.2008.926691
PMC
PMC2738844
OpenAlex
W2154069304
Semantic Scholar
50f65e3db048ec40fda75664ddf9220de6d2fc7a
Cited by
57
References
36
Citations by year
2026: 1 · 2025: 1 · 2024: 1 · 2023: 2 · 2022: 6 · 2021: 3 · 2020: 5 · 2019: 5 · 2018: 4 · 2017: 1 · 2016: 6 · 2015: 5 · 2014: 4 · 2013: 5 · 2012: 3
FWCI
1.11
Type
journal article
Language
en
Open access
Licence
ieeexplore.ieee.org/Xplorehelp/downloads/license-information/IEEE.html (vor)
Locations
  • IEEE Transactions on Biomedical Engineering (publishedVersion)
  • PubMed (publishedVersion)
  • PubMed Central (acceptedVersion)
Funders
National Institute of Neurological Disorders and Stroke (R01NS032845)
Topics
  • Life Sciences › Neuroscience › Cellular and Molecular Neuroscience › Neuroscience and Neural Engineering
  • Physical Sciences › Materials Science › Polymers and Plastics › Conducting polymers and applications
  • Life Sciences › Neuroscience › Neurology › Vagus Nerve Stimulation Research
Keywords
iridium oxide films, liquid crystal polymer substrate, sputtered thin films, water window, oxygen reduction reaction
MeSH terms
Electric Stimulation, Electrochemistry, Electrodes, Electric Stimulation Therapy, Iridium, Microscopy, Electron, Scanning, Oxygen, Polymers, Prosthesis Design

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-09.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-09.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

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