A silicon carbide array for electrocorticography and peripheral nerve recording

Diaz-Botia, Camilo; Luna, Lunet E.; Neely, Ryan; Chamanzar, Maysamreza; Carraro, Carlo; Carmena, Jose M.; Sabes, Philip N.; Maboudian, Roya; Maharbiz, Michel M.

doi:10.1088/1741-2552/aa7698

Cited by 47 publications

(58 citation statements)

References 23 publications

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“…The deposition of two layers of parylene sandwiched the CNT electrode which protruded to reduce the gap between the nerve and the conductive site . To increase device longevity while maintain flexibility, polycrystalline conductive silicon carbide (SiC) has been used with insulating SiC to create electrodes for electrocorticography and peripheral nerve recording . All of these devices are excellent approaches in addressing the mechanical mismatch issue, however, they are still surface electrodes whose axonal selectivity may not be ideal.…”

Section: Introductionmentioning

confidence: 99%

Soft Conducting Elastomer for Peripheral Nerve Interface

Zheng

Woeppel

Griffith

et al. 2019

Adv Healthcare Materials

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State‐of‐the‐art intraneural electrodes made from silicon or polyimide substrates have shown promise in selectively modulating efferent and afferent activity in the peripheral nervous system. However, when chronically implanted, these devices trigger a multiphase foreign body response ending in device encapsulation. The presence of encapsulation increases the distance between the electrode and the excitable tissue, which not only reduces the recordable signal amplitude but also requires increased current to activate nearby axons. Herein, this study reports a novel conducting polymer based intraneural electrode which has Young's moduli similar to that of nerve tissue. The study first describes material optimization of the soft wire conductive matrix and evaluates their mechanical and electrochemical properties. Second, the study demonstrates 3T3 cell survival when cultured with media eluted from the soft wires. Third, the study presents acute in vivo functionality for stimulation of peripheral nerves to evoke force and compound muscle action potential in a rat model. Furthermore, comprehensive histological analyses show that soft wires elicit significantly less scar tissue encapsulation, less changes to axon size, density and morphology, and reduced macrophage activation compared to polyimide implants in the sciatic nerves at 1 month postimplantation.

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Section: Introductionmentioning

confidence: 99%

Soft Conducting Elastomer for Peripheral Nerve Interface

Zheng

Woeppel

Griffith

et al. 2019

Adv Healthcare Materials

View full text Add to dashboard Cite

show abstract

“…Passive flexible and stretchable arrays have been chronically implanted in rodents and large animal models . Their encapsulation materials include plastics, e.g., polyimide, Parylene‐C, and elastomers, eventually combined with thin inorganic dielectric films, e.g., SiO x , SiN x , or SiC . Active implants based on single or multiple microLEDS or thin film transistors systems have been successfully implanted for months using engineered water‐barrier materials especially around the LEDs .…”

Section: Maturity Of Hybrid Technologiesmentioning

confidence: 99%

Section: Challenges For Future Implantable Bioelectronic Interfacesmentioning

confidence: 99%

Conformable Hybrid Systems for Implantable Bioelectronic Interfaces

2019

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of Things (IoT) to wellness and medical technologies. In the past decade, significant efforts have been deployed to exploit these technologies to design and manufacture conformable bioelectronic interfaces.Mechanical compliance is a critical specification for the long-term integration of on-skin devices and implants with a biological host. The latter is largely composed of soft tissues, with Young's moduli E in the range from 100 Pa to 10 MPa (excluding bones and cartilage), [1] and sustains different physiological dynamic behaviors, e.g., repeated displacements of hundreds of micrometers at 1 Hz in the heart or brain, [2] volumetric changes up to 8% in the heart, [3] or large flexion and angular displacement in the skin or spinal cord. [4] In contrast, electronic materials are stiff, with the elastic modulus in the range of 1 GPa (organic materials) to 100 GPa (inorganic materials) and rigid, bearing little strain without displaying mechanical failure or defect generation. Interfaces between such disparate biological and man-made materials suffer therefore from a mechanical mismatch that hinders reliable and continued device function in the body. [1,5] Several approaches have been used to engineer mechanical compliance within an electronic device or circuit. [6] Outcomes of such conformable circuits include improved mitigation of foreign body reaction (FBR) in vivo compared to rigid interfaces, [7] access to so far unreachable regions, [8] and bidirectional communication with high spatiotemporal resolution with the biological host.Monolithic integration of electronic devices and circuits on semiconductor wafers offers extreme miniaturization and very high device density (e.g., >10 8 transistors mm −2 , Intel FinFET Technology nodes [9] ). Such large scale of integration cannot be achieved for electronics prepared on conformable carrier substrates, as this class of devices employs lower performance device materials and polymeric substrates with low chemical and/or thermal stability leading to limited lithographic resolution and large transistor sizes. These constraints typically worsen as the compliance of the substrate increases. Some of the highest device densities reported to date are >10 000 cm −2 on flexible substrate [10] and 347 cm −2 on stretchable carrier. [11] Conformable hybrid systems leverage the performance of standard complementary metal-oxide-semiconductor integrated circuits (ICs) and the compliance of discrete flexible or stretchable components and carriers, to effectively provide high-performance and mechanically compliant electronic circuits. They call for new Conformable bioelectronic systems are promising tools that may aid the understanding of diseases, alleviate pathological symptoms such as chronic pain, heart arrhythmia, and dysfunctions, and assist in reversing conditions such as deafness, blindness, and paralysis. Combining reduced invasiveness with advanced electronic functions, hybrid bioelectronic systems have evolved tremendously in the last decade, pushed by progress in materials ...

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“…As covered in Section 2, many of the functional properties and risk factors associated with neuroimplantable devices stem from material selections and form factor. [120] However, the surgical protocols and methods for implantation, i.e., the implantation procedure, have been shown to greatly contribute to clinical safety concerns, [121,122] fidelity of interfacing, [123] and efficacy of treatment. [123] Historically, the implantation of neural probes-including epicortical systems like ECoG, intracortical systems like the Utah array, and deep brain systems like DBS-have required the use of stereotactic craniotomy.…”

Section: Implantation-related Risk Factorsmentioning

confidence: 99%

“…Encapsulation of other form factors, such as the planar ECoG with silicon carbide has been demonstrated to improve biocompatibility and device longevity. [120] Material selection plays a crucial role in the response of brain tissue toward implanted devices. Transition metals such as tungsten and silicon have relatively high rigidity and poor biocompatibility, which is primarily the result of corrosion.…”

Section: Biological Risk Factors In Relation To Probe Type Form Factmentioning

confidence: 99%

The Future of Neuroimplantable Devices: A Materials Science and Regulatory Perspective

2019

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The past two decades have seen unprecedented progress in the development of novel materials, form factors, and functionalities in neuroimplantable technologies, including electrocorticography (ECoG) systems, multielectrode arrays (MEAs), Stentrode, and deep brain probes. The key considerations for the development of such devices intended for acute implantation and chronic use, from the perspective of biocompatible hybrid materials incorporation, conformable device design, implantation procedures, and mechanical and biological risk factors, are highlighted. These topics are connected with the role that the U.S. Food and Drug Administration (FDA) plays in its regulation of neuroimplantable technologies based on the above parameters. Existing neuroimplantable devices and efforts to improve their materials and implantation protocols are first discussed in detail. The effects of device implantation with regards to biocompatibility and brain heterogeneity are then explored. Topics examined include brain‐specific risk factors, such as bacterial infection, tissue scarring, inflammation, and vasculature damage, as well as efforts to manage these dangers through emerging hybrid, bioelectronic device architectures. The current challenges of gaining clinical approval by the FDA—in particular, with regards to biological, mechanical, and materials risk factors—are summarized. The available regulatory pathways to accelerate next‐generation neuroimplantable devices to market are then discussed.

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A silicon carbide array for electrocorticography and peripheral nerve recording

Abstract: Clinical translation in neural engineering has been slowed in part due to the poor long term performance of current probes. Silicon carbide devices are a promising technology that may accelerate this transition by enabling truly chronic applications.

Cited by 47 publications

References 23 publications

Soft Conducting Elastomer for Peripheral Nerve Interface

Soft Conducting Elastomer for Peripheral Nerve Interface

Conformable Hybrid Systems for Implantable Bioelectronic Interfaces

The Future of Neuroimplantable Devices: A Materials Science and Regulatory Perspective

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