Flexible 3D-Printed EEG Electrodes

Velcescu, Andrei; Lindley, Alexander; Cursio, Ciro; Krachunov, Sammy; Beach, Christopher; Brown, Christopher; Jones, Anthony; Casson, Alexander J.

doi:10.3390/s19071650

Cited by 37 publications

(76 citation statements)

References 12 publications

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“…Typical group delays are in the µs range and so small compared to most electrophysiological signal time-spans [5] but not necessarily negligible. Measurements of group delay are included in our phantom characterisation results presented here.…”

Section: Biological Target To Modelmentioning

confidence: 99%

“…a head in [21]) this was mainly for aesthetic purposes and to provide space for connecting multiple electrodes. Our more recent phantoms have used a cuboid shape [5] as this provides a uniform test structure with a flat surface for electrode connection, and our cuboids are sized to fit in with test infrastructure which allows fixed forces to be applied to electrodes to measure the effect of pressure and similar (as reported in [5]). This cuboid shape is now our preferred mould for day-to-day electrode testing where 1-2 electrode configurations/types are considered at a time, and is used in this paper rather than a full head shape.…”

Section: Test Phantom Creationmentioning

confidence: 99%

“…A gold standard Ag/AgCl electrode was connected to the phantom and the magnitude and phase of the impedance path between the internal and external Ag/AgCl electrodes measured. The external electrode was held in place with the mechanical testing structure described in [5] with a 135 g mass used to fix the contact pressure between the electrode and the gelatine phantom. This surface Ag/AgCl electrode is common to all of the measurements carried out and included in the reported impedances.…”

Section: A Impedance Measurementsmentioning

confidence: 99%

“…The methods and materials for making this phantom have been released in an open source manner [14], and this phantom has also been used to investigate EEG components collected during walking motions [15] where the true EEG is normally unknown as it is obscured by artefacts. Cuboid shaped phantoms were used in [5] to verify the performance of 3D printed EEG electrodes, and to demonstrate how the electrode performance varied with contact force. Some research groups have even applied transcranial Electrical Stimulation (tES) to these phantoms to investigate the tES artefact removal problem from EEG where a known EEG signal can now be provided [16], [17].…”

Section: Introductionmentioning

confidence: 99%

“…The result is that a wide number of different materials have been investigated for making electrophysiology body phantoms (gelatine [2], [5], [13], [15], [16], wax [28], silicon [28], [14]. Image taken from the public domain [20].…”

Section: Introductionmentioning

confidence: 99%

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Electrical properties, accuracy, and multi-day performance of gelatine phantoms for electrophysiology

Owda

Casson

2020

Preprint

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Gelatine based phantoms for electrophysiology are becoming widely used as they allow the controlled validation of new electrode and new instrumentation designs. The phantoms mimic the electrical properties of the human body and allow a pre-recorded electrophysiology signal to be played-out, giving a known signal for the novel electrode or instrumentation to collect. Such controlled testing is not possible with on-person experiments where the signal to be recorded is intrinsically unknown. However, despite the rising interest in gelatine based phantoms there is relatively little public information about their electrical properties and accuracy, how these vary with phantom formulation, and across both time and frequency. This paper investigates ten different phantom configurations, characterising the impedance path through the phantom and comparing this impedance path to both previously reported electrical models of Ag/AgCl electrodes placed on skin and to a model made from ex vivo porcine skin. This article shows how the electrical properties of the phantoms can be tuned using different concentrations of gelatine and of sodium chloride (NaCl) added to the mixture, and how these properties vary over the course of seven days for a.c. frequencies in the range 20-1000 Hz. The results demonstrate that gelatine phantoms can accurately mimic the frequency response properties of the body-electrode system to allow for the controlled testing of new electrode and instrumentation designs.

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Section: Biological Target To Modelmentioning

confidence: 99%

Section: Test Phantom Creationmentioning

confidence: 99%

Section: A Impedance Measurementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Electrical properties, accuracy, and multi-day performance of gelatine phantoms for electrophysiology

Owda

Casson

2020

Preprint

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3D Printed Neural Regeneration Devices

Joung

Lavoie

Guo

et al. 2019

Adv Funct Materials

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Neural regeneration devices interface with the nervous system and can provide flexibility in material choice, implantation without the need for additional surgeries, and the ability to serve as guides augmented with physical, biological (e.g., cellular), and biochemical functionalities. Given the complexity and challenges associated with neural regeneration, a 3D printing approach to the design and manufacturing of neural devices can provide next-generation opportunities for advanced neural regeneration via the production of anatomically accurate geometries, spatial distributions of cellular components, and incorporation of therapeutic biomolecules. A 3D printing-based approach offers compatibility with 3D scanning, computer modeling, choice of input material, and increasing control over hierarchical integration. Therefore, a 3D printed implantable platform can ultimately be used to prepare novel biomimetic scaffolds and model complex tissue architectures for clinical implants in order to treat neurological diseases and injuries. Further, the flexibility and specificity offered by 3D printed in vitro platforms have the potential to be a significant foundational breakthrough with broad research implications in cell signaling and drug screening for personalized healthcare. This progress report examines recent advances in 3D printing strategies for neural regeneration as well as insight into how these approaches can be improved in future studies.spinal cord, and the peripheral nervous system (PNS), composed of the cranial and spinal nerves along with their associated ganglia that connect the CNS to the body. These systems are interconnected via an extensive network of nerves and neural cells (i.e., neurons and supporting glial cells) to facilitate communication and relay information (sensorimotor signals) to and from all parts of the body.

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3D Printed Dry Electrodes for Electrophysiological Signal Monitoring: A Review

Alsharif

Cucuri

Mishra

et al. 2023

Adv Materials Technologies

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EP electrodes are classified into two main categories: invasive (internal) and non-invasive (external). Non-invasive electrodes involve a harmless approach that detects EP signals from the surface of the human skin. [13,14] Human skin is divided into two main layers: the epidermis and dermis. The outer layer of human skin, the stratum corneum on the epidermis, has outstanding electrode-skin impedance features. [15] Therefore, while employing noninvasive electrodes for EP signal detection, it is essential to minimize the effect of the stratum corneum completely and thoroughly. Majority of the non-invasive electrodes are used in medical monitoring systems and are composed of silver/silver chloride (Ag/AgCl) electrodes, [16][17][18][19] which have been utilized for many years. [20,21] In fact, state-of-the-art non-invasive electrodes are traditionally classified into three types based on the proportion of electrolytes present at the electrodeskin interface: wet electrodes, semi-dry electrodes, and dry electrodes. [22] Traditional wet electrodes setup includes Ag/AgCl electrodes and conductive gels that lowers the electrode-skin impedance between the electrodes and the epidermal layer of the human skin. The introduction of the gel plays an important role in establishing a non-polarized electrode-electrolyte interface and a stable electrode-skin interface. However, conductive gels or pastes limit the long-term monitoring of electrodes because of its tendency to cause skin irritation. [23] They can dehydrate and coagulate after prolonged use, thereby increasing the signal detection noise and degrading the signal quality. [24] In recent decades, several approaches have been developed to fabricate dry electrodes that do not require wet gels, making them a promising alternative as they have enhanced signal quality, portability, and ease of use. [25] Dry electrodes have clearly demonstrated several advantages, including rapid setup as well as user comfort due to the absence of conductive gels, skin preparation, and post-monitor cleaning. However, due to a lack of electrolytes, dry electrodes typically produce high electrode-skin impedance values that are substantially greater than those of wet electrodes. Furthermore, dry electrodes are prone to ambient noise and movement artifacts, making them unsuitable for mobile applications such as sports and where movement is required due to the noise produced in the EP signal. [22] The semi-dry electrode came out to be the most promising option. Although this term is out of the scope of this paper, semi-dry electrodes replaced the conductive gels 3D printed on-skin electrodes are of notable interest because, unlike traditional wet silver/silver chloride (Ag/AgCl) on-skin electrodes, they can be personalized and 3D printed using a variety of materials with distinct properties such as stretchability, conformal interfaces with skin, biocompatibility, wearable comfort, and, finally, low-cost manufacturing. Dry on-skin electrodes, in particular, have the additional advantage of replacing...

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Flexible 3D-Printed EEG Electrodes

Cited by 37 publications

References 12 publications

Electrical properties, accuracy, and multi-day performance of gelatine phantoms for electrophysiology

Electrical properties, accuracy, and multi-day performance of gelatine phantoms for electrophysiology

3D Printed Neural Regeneration Devices

3D Printed Dry Electrodes for Electrophysiological Signal Monitoring: A Review

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