Electrochemical characteristics of ultramicro-dimensioned SIROF electrodes for neural stimulation and recording

Ghazavi, Atefeh; Maeng, Jimin; Black, Michael J.; Salvi, S; Cogan, Stuart F.

doi:10.1088/1741-2552/ab52ab

Cited by 23 publications

(16 citation statements)

References 52 publications

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“…The CSC reported in this work was from 0.0730 to 4.3124 C/cm 2 . The values reported here were very promising compared to the values reported in the literature for recently reported on sputtered iridium oxide film (SIROF) [26] and poly (3,4-ethylenedioxythiophene) (PEDOT):Nafion-based electrodes [27].…”

Section: Discussionsupporting

confidence: 80%

Highly Flexible Polyaniline-Based Implantable Electrode Materials for Neural Sensing/Stimulation Applications

Almufleh

Al‐Othman

Alani

et al. 2021

Electronic Materials

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Implantable bioelectrodes have the potential to advance neural sensing and muscle stimulation, mainly in patients with peripheral nerve injuries. They function as the transducer at the interface between the damaged nerve and the muscle which is controlled by that nerve. This work reports the fabrication and characterization of novel, low-cost, flexible bioelectrodes based on polyaniline (PANI) and supported with silicone polymer. The fabricated electrodes were evaluated for their electrical and mechanical characteristics. PANI was used as the main transducer component in this fabrication. The characterization methods included electrical conductivity, capacitive behavior, long-term electrical impedance, and mechanical evaluation. The results of the fabricated PANI-silicone-based samples displayed a bulk impedance of 0.6 kΩ with an impedance of 1.6 kΩ at the frequency of 1 kHz. Furthermore, the bioelectrodes showed a charge storage capacity range from 0.0730 to 4.3124 C/cm2. The samples were stable when subjected to cyclic voltammetry tests. The bioelectrodes revealed very flexible mechanical properties as observed from the value of Young’s modulus (in the order of MPa) which was less than that of skin. Hence, the PANI-based bioelectrodes reported herein showed promising electrochemical characteristics with high flexibility.

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Section: Discussionsupporting

confidence: 80%

Highly Flexible Polyaniline-Based Implantable Electrode Materials for Neural Sensing/Stimulation Applications

Almufleh

Al‐Othman

Alani

et al. 2021

Electronic Materials

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“…Ir/IrOx (iridium oxide) is another prevailing electrode material and often used in the format of either a bulky wire or a thin film coating (Zeng et al, 2017 ; Black et al, 2018b ; Chen et al, 2019 ; Ghazavi et al, 2020 ). Ir wires are very stiff and highly resistant to corrosion (Loeb et al, 1995 ), whereas IrOx thin films are unstable and prone to degradation as electrode dimensions decrease and charge densities increase (Cogan et al, 2004 ).…”

Section: Electrode Materialsmentioning

confidence: 99%

A Review: Electrode and Packaging Materials for Neurophysiology Recording Implants

Yang

Gong

2021

Front. Bioeng. Biotechnol.

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To date, a wide variety of neural tissue implants have been developed for neurophysiology recording from living tissues. An ideal neural implant should minimize the damage to the tissue and perform reliably and accurately for long periods of time. Therefore, the materials utilized to fabricate the neural recording implants become a critical factor. The materials of these devices could be classified into two broad categories: electrode materials as well as packaging and substrate materials. In this review, inorganic (metals and semiconductors), organic (conducting polymers), and carbon-based (graphene and carbon nanostructures) electrode materials are reviewed individually in terms of various neural recording devices that are reported in recent years. Properties of these materials, including electrical properties, mechanical properties, stability, biodegradability/bioresorbability, biocompatibility, and optical properties, and their critical importance to neural recording quality and device capabilities, are discussed. For the packaging and substrate materials, different material properties are desired for the chronic implantation of devices in the complex environment of the body, such as biocompatibility and moisture and gas hermeticity. This review summarizes common solid and soft packaging materials used in a variety of neural interface electrode designs, as well as their packaging performances. Besides, several biopolymers typically applied over the electrode package to reinforce the mechanical rigidity of devices during insertion, or to reduce the immune response and inflammation at the device-tissue interfaces are highlighted. Finally, a benchmark analysis of the discussed materials and an outlook of the future research trends are concluded.

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“…Compared with previously published, comparable SIROFs, the CIC of the presented material is one of the highest in the literature. (3,4,7,10,21,26,27) This ensures the safe and efficient stimulation of neural tissues in a wide range of acceptable operations (Fig. 1).…”

Section: R S (Kω)mentioning

confidence: 99%

Sputtered Iridium Oxide as Electrode Material for Subretinal Stimulation

Haas¹,

Rudorf²,

Becker³

et al. 2020

Sensors and Materials

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The efficiency and safety of neuronal stimulation with implants strongly depend on the electrode material. Microelectrodes composed of iridium oxide are becoming increasingly important as they exhibit excellent charge injection capacity (CIC) as well as charge storage capacity (CSC). We present the development of a robust process for the fabrication of sputtered iridium oxide films (SIROF). This process has been used for the "RETINA IMPLANT Alpha AMS" for several years of subretinal stimulation. In this paper, we describe the full experimental investigation of the electrode material. The electrochemical and morphological properties were investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), voltage transient measurements, and focused ion beam-scanning electron microscopy (FIB-SEM). The implementation on the CMOS chip of the retinal prosthesis is presented. The deposition process window was investigated extensively. Major changes in process parameters lead to a difference in impedance of only 10% of the mean. Accelerated aging tests revealed a long-term stability of the electrodes of at least 10 years under conditions of use. The SIROF electrodes (diameter 30 µm) show low impedance (15.9 kΩ), excellent CSC (50.9 mC/cm 2), and high CIC (4.2 mC/cm 2). In summary, the robustness of the presented deposition process and the large process window enable the integration of high-quality SIROF microelectrodes in active implants and thus long-term stability in a wide range of safe electrical stimulation.

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Electrochemical characteristics of ultramicro-dimensioned SIROF electrodes for neural stimulation and recording

Cited by 23 publications

References 52 publications

Highly Flexible Polyaniline-Based Implantable Electrode Materials for Neural Sensing/Stimulation Applications

Highly Flexible Polyaniline-Based Implantable Electrode Materials for Neural Sensing/Stimulation Applications

A Review: Electrode and Packaging Materials for Neurophysiology Recording Implants

Sputtered Iridium Oxide as Electrode Material for Subretinal Stimulation

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