Ultra-thin flexible polyimide neural probe embedded in a dissolvable maltose-coated microneedle

Xiang, Zhuolin; Yen, Shih Cheng; Xue, Ning; Sun, Tao; Tsang, W.M.; Zhang, Songsong; Liao, Lun-De; Thakor, Nitish V.; Lee, Chengkuo

doi:10.1088/0960-1317/24/6/065015

Cited by 138 publications

(118 citation statements)

References 75 publications

(78 reference statements)

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“…An LCGO electrode was coated with a sucrose microneedle vehicle using a drawing lithography technique. [21,43] An anesthetised adult, male feline was placed in a stereotaxic frame and a craniotomy was performed over the visual cortex. The dura mater was removed carefully and the wound irrigated with sterile were bandpass filtered (300-5000 kHz) and spikes were counted in IgorPro (Wavemetrics).…”

Section: Methodsmentioning

confidence: 99%

“…[21,43] The needle shown in Figure 2d dissolved in approximately 3 minutes time in room temperature tap water resulting in the exposed LCGO electrode shown in Figure 2e.…”

Section: Electrode Fabricationmentioning

confidence: 99%

“…This method of forming a microneedle has been previously employed for drug delivery, as well as flexible polyimide electrode insertion into neural tissue. [21,43] Spontaneous neural bursting activity was observed approximately 30 seconds after electrode implantation, suggesting sugar dissolution and exposure of electrode active site. The sugar dissolved much more quickly in the brain than it did in the benchtop test with room temperature tap water because sugar's solubility in water increases with temperature.…”

Section: In Vivo Implantation Of Lcgo Electrodementioning

confidence: 99%

“…Flexible fibres have been inserted into tissue using dissolvable coatings such as gelatin, [19] silk, [20] and maltose. [21] Carbon nanotube bundle electrodes on flexible substrates have been inserted into the brain using a rigid gold wire carrier. [22] In addition to favourable mechanical properties, the surface chemistry of implanted electrodes has been studied to enhance biocompatibility.…”

Section: Introductionmentioning

confidence: 99%

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Soft, Flexible Freestanding Neural Stimulation and Recording Electrodes Fabricated from Reduced Graphene Oxide

Apollo

Maturana

Tong

et al. 2015

Adv Funct Materials

129

148

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. (2015). Soft, flexible freestanding neural stimulation and recording electrodes fabricated from reduced graphene oxide. Advanced Functional Materials, 25 (23), 3551-3559. Soft, flexible freestanding neural stimulation and recording electrodes fabricated from reduced graphene oxide AbstractThere is an urgent need for conductive neural interfacing materials that exhibit mechanically compliant properties, while also retaining high strength and durability under physiological conditions. Currently, implantable electrode systems designed to stimulate and record neural activity are composed of rigid materials such as crystalline silicon and noble metals. While these materials are strong and chemically stable, their intrinsic stiffness and density induce glial scarring and eventual loss of electrode function in vivo. Conductive composites, such as polymers and hydrogels, have excellent electrochemical and mechanical properties, but are electrodeposited onto rigid and dense metallic substrates. In the work described here, strong and conductive microfibers (40-50 μm diameter) wet-spun from liquid crystalline dispersions of graphene oxide are fabricated into freestanding neural stimulation electrodes. The fibers are insulated with parylene-C and laser-treated, forming "brush" electrodes with diameters over 3.5 times that of the fiber shank. The fabrication method is fast, repeatable, and scalable for high-density 3D array structures and does not require additional welding or attachment of larger electrodes to wires. The electrodes are characterized electrochemically and used to stimulate live retina in vitro. Additionally, the electrodes are coated in a water-soluble sugar microneedle for implantation into, and subsequent recording from, visual cortex. AbstractThere is an urgent need for conductive neural interfacing materials that exhibit mechanicallycompliant properties while also retaining high strength and durability in physiological conditions. Currently, implantable electrode systems designed to stimulate and record neural activity are comprised of rigid materials such as crystalline silicon and noble metals. While these materials are strong and chemically stable, their intrinsic stiffness and density induce glial scarring and eventual loss of electrode function in vivo. Conductive composites, such as polymers and hydrogels, have excellent electrochemical and mechanical properties, but are electrodeposited onto rigid and dense metallic substrates. In the work described here, strong and conductive microfibres (40-50 µm diameter) wet-spun from liquid crystalline dispersions of graphene oxide are fabricated into freestanding neural stimulation electrodes. The fibres were insulated with parylene-C and laser-treated, forming "brush" electrodes with diameters over 3.5 times that of the fibre shank. The fabrication method is fast, repeatable, and scalable for high density 3-D array structures and does not require additional welding or attachment of larger electrodes to wires. The electrodes are characterized electroch...

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Section: Methodsmentioning

confidence: 99%

“…[21,43] The needle shown in Figure 2d dissolved in approximately 3 minutes time in room temperature tap water resulting in the exposed LCGO electrode shown in Figure 2e.…”

Section: Electrode Fabricationmentioning

confidence: 99%

Section: In Vivo Implantation Of Lcgo Electrodementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Soft, Flexible Freestanding Neural Stimulation and Recording Electrodes Fabricated from Reduced Graphene Oxide

Apollo

Maturana

Tong

et al. 2015

Adv Funct Materials

129

148

View full text Add to dashboard Cite

show abstract

“…Another common concern for the central neural interface is whether it is strong enough to penetrate the brain tissue 39 . To prove that the microneedles have sufficient stiffness for successful penetration, the buckling force was tested.…”

Section: Results and Discussion Length Dependency Of The Microneedle mentioning

confidence: 99%

A flexible three-dimensional electrode mesh: An enabling technology for wireless brain–computer interface prostheses

2016

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The neural interface is a key component in wireless brain-computer prostheses. In this study, we demonstrate that a unique three-dimensional (3D) microneedle electrode on a flexible mesh substrate, which can be fabricated without complicated micromachining techniques, is conformal to the tissues with minimal invasiveness. Furthermore, we demonstrate that it can be applied to different functional layers in the nervous system without length limitation. The microneedle electrode is fabricated using drawing lithography technology from biocompatible materials. In this approach, the profile of a 3D microneedle electrode array is determined by the design of a two-dimensional (2D) pattern on the mask, which can be used to access different functional layers in different locations of the brain. Due to the sufficient stiffness of the electrode and the excellent flexibility of the mesh substrate, the electrode can penetrate into the tissue with its bottom layer fully conformal to the curved brain surface. Then, the exposed contact at the end of the microneedle electrode can successfully acquire neural signals from the brain. INTRODUCTIONBrain-computer prostheses provide a bridge for humans to understand and communicate with the nervous system. Neural interfaces are a key component enabling wireless brain-computer prostheses for long-term implantation. In the last decades, researchers have developed various types of neural interfaces based on advanced functional materials and fabrication technology [1][2][3] . Because a two-dimensional (2D) structure can be shaped precisely and easily, most neural interfaces are fabricated into planar geometries, which are known as neural probes. However, neural tissues are normally three-dimensional (3D) structures, and 2D neural probes are limited to recording signals from only planar brain regions

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Development and Characterization of a Sucrose Microneedle Neural Electrode Delivery System

et al. 2017

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Stable brain–machine interfaces present extraordinary therapeutic and scientific promise. However, the electrode–tissue interface is susceptible to instability and damage during long‐term implantation. Soft, flexible electrodes demonstrate improved longevity, but pose a new challenge with regard to simple and accurate surgical implantation. A high aspect ratio water‐soluble microneedle is developed based on sucrose which permits straightforward surgical implantation of soft, flexible microelectrodes. Here, a description of the microneedle manufacturing process is presented, along with in vitro and in vivo safety and efficacy assessments. Successful fabrication requires control of the glass transition temperature of aqueous sucrose solutions. The insertion force of 5 different microneedle electrode vehicles is studied in agarose brain phantoms, with the sucrose microneedle eliciting the lowest insertion force and strain energy transfer. Short‐ and long‐term assessments of the pathological response to sucrose microneedle implantations in the brain suggest minimal tissue reactions, comparable to those observed following stainless‐steel hypodermic needle punctures. Finally, microelectrodes fabricated from graphene, carbon nanotubes, or platinum are embedded in sucrose microneedles and implanted into an epileptic rat model for 22 d. All electrodes are functional throughout the implantation period, with the graphene electrode exhibiting the largest seizure signal‐to‐noise ratio and only modest changes in impedance.

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Ultra-thin flexible polyimide neural probe embedded in a dissolvable maltose-coated microneedle

Cited by 138 publications

References 75 publications

Soft, Flexible Freestanding Neural Stimulation and Recording Electrodes Fabricated from Reduced Graphene Oxide

Soft, Flexible Freestanding Neural Stimulation and Recording Electrodes Fabricated from Reduced Graphene Oxide

A flexible three-dimensional electrode mesh: An enabling technology for wireless brain–computer interface prostheses

Development and Characterization of a Sucrose Microneedle Neural Electrode Delivery System

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