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Simultaneous photoadhesion and photopatterning technique for passivation of flexible neural electrodes based on fluoropolymers.

ABSTRACT: Herein, we introduce a method to simultaneously photoadhere a photocrosslinkable polymer to a plasma-treated fluoropolymer while photopatterning the photocrosslinkable polymer via a single-photo-exposure as a new electrode passivation technique. Photoadhesion was determined to result from plasma-generated radicals of the plasma-treated fluoropolymer. Crystallinity of the fluoropolymer was analysed to determine the photoadhesion strength through its effects on both the formation of radicals and the etching of fluoropolymers. Passivation feasibility of simultaneous photoadhesion and photopatterning (P&P) technique were demonstrated by fabricating an Au electrocorticography electrode array and modifying the electrode with electro-deposited metallic nanoparticles. Adhesion of sputter-deposited Au to the fluoropolymer was dependent on mechanical interlocking, indicated by the formation of Au clusters which are typically influenced by the surface temperature during the sputter-deposition and the glass transition temperature of the fluoropolymer. The adhesion of Au to the fluoropolymer without an additional adhesion promotor and the proposed P&P passivation technique would help prevent detachment of the electrode and the delamination of the passivation layer in fluoropolymer-based neural electrode.

SUBMITTER: Kim YH

PROVIDER: S-EPMC7721713 | biostudies-literature | 2020 Dec

REPOSITORIES: biostudies-literature

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Simultaneous photoadhesion and photopatterning technique for passivation of flexible neural electrodes based on fluoropolymers.

Kim Yong Hee YH Jung Sang-Don SD

Scientific reports 20201207 1

Herein, we introduce a method to simultaneously photoadhere a photocrosslinkable polymer to a plasma-treated fluoropolymer while photopatterning the photocrosslinkable polymer via a single-photo-exposure as a new electrode passivation technique. Photoadhesion was determined to result from plasma-generated radicals of the plasma-treated fluoropolymer. Crystallinity of the fluoropolymer was analysed to determine the photoadhesion strength through its effects on both the formation of radicals and t ...[more]

PMID: 33288811

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Project description:Objective.Brain functions such as perception, motor control, learning, and memory arise from the coordinated activity of neuronal assemblies distributed across multiple brain regions. While major progress has been made in understanding the function of individual neurons, circuit interactions remain poorly understood. A fundamental obstacle to deciphering circuit interactions is the limited availability of research tools to observe and manipulate the activity of large, distributed neuronal populations in humans. Here we describe the development, validation, and dissemination of flexible, high-resolution, thin-film (TF) electrodes for recording neural activity in animals and humans.Approach.We leveraged standard flexible printed-circuit manufacturing processes to build high-resolution TF electrode arrays. We used biocompatible materials to form the substrate (liquid crystal polymer; LCP), metals (Au, PtIr, and Pd), molding (medical-grade silicone), and 3D-printed housing (nylon). We designed a custom, miniaturized, digitizing headstage to reduce the number of cables required to connect to the acquisition system and reduce the distance between the electrodes and the amplifiers. A custom mechanical system enabled the electrodes and headstages to be pre-assembled prior to sterilization, minimizing the setup time required in the operating room. PtIr electrode coatings lowered impedance and enabled stimulation. High-volume, commercial manufacturing enables cost-effective production of LCP-TF electrodes in large quantities.Main Results. Our LCP-TF arrays achieve 25× higher electrode density, 20× higher channel count, and 11× reduced stiffness than conventional clinical electrodes. We validated our LCP-TF electrodes in multiple human intraoperative recording sessions and have disseminated this technology to >10 research groups. Using these arrays, we have observed high-frequency neural activity with sub-millimeter resolution.Significance.Our LCP-TF electrodes will advance human neuroscience research and improve clinical care by enabling broad access to transformative, high-resolution electrode arrays.

Dataset Information

Simultaneous photoadhesion and photopatterning technique for passivation of flexible neural electrodes based on fluoropolymers.

Publications

Simultaneous photoadhesion and photopatterning technique for passivation of flexible neural electrodes based on fluoropolymers.

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