Residual rubber shielded multi walled carbon nanotube electrodes for neural interfacing in active medical implants

Tegtmeier, Katharina; Aliuos, Pooyan; Lenarz, Thomas; Doll, Theodor

doi:10.1016/j.phmed.2016.04.001

Cited by 12 publications

(15 citation statements)

References 27 publications

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“…Silicon rubber (SR) is a gelling material obtained by polycondensation or polyaddition reactions; SRs are widely used for a variety of scopes including tissue implants because of their flexibility and chemical stability . Moreover, in several medical implants such as neuronal implants, there is a need to restore their functionalities by electrical stimulation and in this regard carbon nanotube–SR and graphene/SR composites could be considered as promising candidates for use in tissue implants possessing proper mechanical, electrical as well as biocompatible properties . Auxetic stents made of such biocompatible composites, for example, could help minimizing the negative effects of current stent designs through tailored negative Poisson's ratio, deformation mechanism and enhanced mechanical properties.…”

Section: Introductionmentioning

confidence: 99%

Graphene and Carbon Nanotube Auxetic Rubber Bionic Composites with Negative Variation of the Electrical Resistance and Comparison with Their Nonbionic Counterparts

Valentini

Bon

Pugno

2017

Adv Funct Materials

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Microorganism metabolic activity can facilitate the formation of cellular material systems that have unusual mechanical and physical properties. In the living world microorganisms are commonly used for preparing porous food by fermentation; here carbon nanotubes, graphene nanoplatelets, and a mix of them are dispersed in liquid silicone rubber with single-cell fungi of commercial beer yeast. The fermentation of such microorganisms during the gelling of the silicone matrix results in bionic composites with buckled/collapsed cells that infer, as rationalized with an analytical model and excluded in a abiotic experimental comparison, auxetic properties. During stretching it is found that the Poisson's ratio of such composites changes sign, from negative to positive, and the variation of the electrical resistance is negative. In addition to the conductivity increment, a general increment of the stretchability and damage resistance with respect to the composites prepared by abiotic process is observed. Bionic composites, even if in their infancy, can thus be multifunctional and superior to their traditional/abiotic counterparts.

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Section: Introductionmentioning

confidence: 99%

Graphene and Carbon Nanotube Auxetic Rubber Bionic Composites with Negative Variation of the Electrical Resistance and Comparison with Their Nonbionic Counterparts

Valentini

Bon

Pugno

2017

Adv Funct Materials

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“…Polydimethylsiloxane rubber (PDMS) is either used as insulating wire substrate or mechanical stress‐mediating thin‐film sealant. If mixed with carbon nano tubes (CNT) it may serve as a conducting electrode alternative with good neural interfacing properties and good flexibility …”

Section: State Of the Artmentioning

confidence: 99%

Flexible High Density Active Neural Implants Combining a Distributed Multiplexing Transceiver Architecture with Biocompatible Technology

Marcoleta

Nogueira

Froriep

et al. 2018

Physica Status Solidi (a)

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Precise localization of brain tissue causing severe neurological conditions requires subdural recording arrays with high electrode density and low mechanical stiffness compliant with the brain tissue. However, most arrays currently used À such as clinical ECoG grids À are rather stiff and limited in spatial resolution. To overcome these constrains a novel architecture is proposed using delocalized electronic (de)multiplexer grains. Here, their functional units are described in both hard-and software, and tested in simulations and experimentally. The results show that in case of a 100 Â 100 mm ECoG array with lower mechanical stiffness, inter-electrode distances <1 mm can be achieved. Taking parasitic capacitances into account, a signal resolution of 100 μV is reached with an inter-channel timing resolution of 200 ns, which in our model corresponds to tissue localization as precise as 1.2 mm. For clinical application of envisaged 5000 electrodes, a preselection mechanism and routes for adoption of this technology toward cochlear implants and brain computer interfaces are presented. J. P. MarcoletaHearing 4 All Cluster of Excellence Biomaterial Engineering Hannover Medical School

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“…Thus, it substantially reduces the risk of CNT release into surrounding tissue and fluids. However, when embedding CNTs, the advantage of the structured surface area is highly decreased [ 24 ]. Thus, the insulating shield on top of the CNTs (e.g., 150 µm in [ 21 ]) has to be removed to expose the required nanostructure of the CNT material.…”

Section: Introductionmentioning

confidence: 99%

“…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 ]. The exposed CNT nanostructure has already been shown to enable attachment of neurites [ 24 ]. Using state-of-the-art thin-film metal electrodes as substrates, conventional recording systems can be used and the electrode performance can directly be compared to that of uncoated metal contacts [ 27 ].…”

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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Residual rubber shielded multi walled carbon nanotube electrodes for neural interfacing in active medical implants

Cited by 12 publications

References 27 publications

Graphene and Carbon Nanotube Auxetic Rubber Bionic Composites with Negative Variation of the Electrical Resistance and Comparison with Their Nonbionic Counterparts

Graphene and Carbon Nanotube Auxetic Rubber Bionic Composites with Negative Variation of the Electrical Resistance and Comparison with Their Nonbionic Counterparts

Flexible High Density Active Neural Implants Combining a Distributed Multiplexing Transceiver Architecture with Biocompatible Technology

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

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