Carbon Nanotube‐Silicone Rubber on Active Thin‐Film Implants

Behrens, Ailke; Foremny, Katharina; Doll, Theodor

doi:10.1002/pssa.201700873

Cited by 7 publications

(13 citation statements)

References 12 publications

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“…In addition, regarding the planned application, coatings can be an option for surface modification to tune impedance characteristics of the electrodes, as already known from ECoG micro arrays and cochlear implant electrode arrays [ 10 , 39 ].…”

Section: Discussionmentioning

confidence: 99%

Laser-Facilitated Additive Manufacturing Enables Fabrication of Biocompatible Neural Devices

Behrens

Stieghorst

Doll

et al. 2020

Sensors

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Current personalized treatment of neurological diseases is limited by availability of appropriate manufacturing methods suitable for long term sensors for neural electrical activities in the brain. An additive manufacturing process for polymer-based biocompatible neural sensors for chronic application towards individualized implants is here presented. To process thermal crosslinking polymers, the developed extrusion process enables, in combination with an infrared (IR)-Laser, accelerated curing directly after passing the outlet of the nozzle. As a result, no additional curing steps are necessary during the build-up. Furthermore, the minimal structure size can be achieved using the laser and, in combination with the extrusion parameters, provide structural resolutions desired. Active implant components fabricated using biocompatible materials for both conductive pathways and insulating cladding keep their biocompatible properties even after the additive manufacturing process. In addition, first characterization of the electric properties in terms of impedance towards application in neural tissues are shown. The printing toolkit developed enables processing of low-viscous, flexible polymeric thermal curing materials for fabrication of individualized neural implants.

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Section: Discussionmentioning

confidence: 99%

Laser-Facilitated Additive Manufacturing Enables Fabrication of Biocompatible Neural Devices

Behrens

Stieghorst

Doll

et al. 2020

Sensors

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“…For the in vivo experiments, the previously evaluated composites with 5 w / w % CNTs in PDMS were used by applying the compound to the contacts using glass blades [ 25 ]. For correlation with the electrophysiological results, the impedances of each recording electrode were measured (1 kHz, 1 V, system: Alpha Omega Engineering).…”

Section: Methodsmentioning

confidence: 99%

“…We previously described a technique for CNT-coating of electrodes by applying a CNT-silicone rubber composite onto metal electrode contacts and a subsequent wet or plasma (dry) etching of the composite surface [ 25 ]. The remaining thin PDMS layer allowed for electron tunneling without releasing CNTs into the tissue due to safe anchoring of the CNTs in the electrode substrate [ 26 ].…”

Section: Introductionmentioning

confidence: 99%

Carbon-Nanotube-Coated Surface Electrodes for Cortical Recordings In Vivo

et al. 2021

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Current developments of electrodes for neural recordings address the need of biomedical research and applications for high spatial acuity in electrophysiological recordings. One approach is the usage of novel materials to overcome electrochemical constraints of state-of-the-art metal contacts. Promising materials are carbon nanotubes (CNTs), as they are well suited for neural interfacing. The CNTs increase the effective contact surface area to decrease high impedances while keeping minimal contact diameters. However, to prevent toxic dissolving of CNTs, an appropriate surface coating is required. In this study, we tested flexible surface electrocorticographic (ECoG) electrodes, coated with a CNT-silicone rubber composite. First, we describe the outcome of surface etching, which exposes the contact nanostructure while anchoring the CNTs. Subsequently, the ECoG electrodes were used for acute in vivo recordings of auditory evoked potentials from the guinea pig auditory cortex. Both the impedances and the signal-to-noise ratios of coated contacts were similar to uncoated gold contacts. This novel approach for a safe application of CNTs, embedded in a surface etched silicone rubber, showed promising results but did not lead to improvements during acute recordings.

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“…Graphitized carbon has similar characteristics to CB, but CB was chosen since its composite with silicone has more favorable bulk conductivity ( Quinsaat et al, 2019 ). Several other silicone composites, such as those of platinum powder ( Minev et al, 2015 ; Schiavone et al, 2018 ) and carbon nanotubes (CNTs) ( Behrens et al, 2018 ; Kim et al, 2018 ), demonstrate better charge transfer impedances. However, CB is far cheaper and easy to disperse.…”

Section: Introductionmentioning

confidence: 99%

Rapid and Low Cost Manufacturing of Cuff Electrodes

et al. 2021

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For many peripheral neuro-modulation applications, the cuff electrode has become a preferred technology for delivering electrical current into targeted volumes of tissue. While basic cuffs with low spatial selectivity, having longitudinally arranged contacts, can be produced from relatively straightforward processes, the fabrication of more complex electrode configurations typically requires iterative design and clean-room fabrication with skilled technicians. Although facile methods for fabricating cuff electrodes exist, their inconsistent products have limited their adoption for rapid manufacturing. In this article, we report a fast, low-cost fabrication process for patterning of electrode contacts in an implantable peripheral nerve cuff. Using a laser cutter as we have prescribed, the designer can render precise contact geometries that are consistent between batches. This method is enabled by the use of silicone/carbon black (CB) composite electrodes, which integrate with the patterned surface of its substrate—tubular silicone insulation. The size and features of its products can be adapted to fit a wide range of nerve diameters and applications. In this study, we specifically documented the manufacturing and evaluation of circumpolar cuffs with radial arrays of three contacts for acute implantation on the rat sciatic nerve. As part of this method, we also detail protocols for verification—electrochemical characterization—and validation—electrophysiological evaluation—of implantable cuff electrodes. Applied to our circumpolar cuff electrode, we report favorable electrical characteristics. In addition, we report that it reproduces expected electrophysiological behaviors described in prior literature. No specialized equipment or fabrication experience was required in our production, and we encountered negligible costs relative to commercially available solutions. Since, as we demonstrate, this process generates consistent and precise electrode geometries, we propose that it has strong merits for use in rapid manufacturing.

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Carbon Nanotube‐Silicone Rubber on Active Thin‐Film Implants

Cited by 7 publications

References 12 publications

Laser-Facilitated Additive Manufacturing Enables Fabrication of Biocompatible Neural Devices

Laser-Facilitated Additive Manufacturing Enables Fabrication of Biocompatible Neural Devices

Carbon-Nanotube-Coated Surface Electrodes for Cortical Recordings In Vivo

Rapid and Low Cost Manufacturing of Cuff Electrodes

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