Highly Stable PEDOT:PSS Coating on Gold Microelectrodes with Improved Charge Injection Capacity for Chronic Neural Stimulation

Pranti, Anmona Shabnam; Schander, Andreas; Bödecker, André; Lang, Walter

doi:10.3390/proceedings1040492

Cited by 21 publications

(17 citation statements)

References 5 publications

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“…as reported previously [58]. The lowest polarisation, however, was noted for multilayered PEDOT/Au substrates and the presence of neuromorphic PEDOT/Au assemblies were found to reduce electrode polarisation by a factor of three [59]. Figure 4E).…”

Section: Electrochemical Performancesupporting

confidence: 85%

Fractal form PEDOT/Au assemblies as thin-film neural interface materials

Krukiewicz¹,

Chudy²,

Vallejo-Giraldo³

et al. 2018

Biomed. Mater.

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Electrically conducting polymer formulations have emerged as promising approaches for the development of interfaces and scaffolds in neural engineering, facilitating the development of physicochemically modified constructs capable of cell stimulation through electrical and ionic charge transfer. In particular, topographically functionalized or neuromorphic materials are able to guide the growth of axons and promote enhanced interfacing with neuroelectrodes in vitro. In this study, we present a novel method for the formation of conducting polymer/gold assemblies via a combinational sputter and spin coating technique. The resulting multilayered PEDOT/Au substrates possessed enhanced electrochemical properties as a function of the number of deposited organic/inorganic layers. It was observed that through subsequent electrochemical conditioning it was possible to form neuromorphic fractal-like assemblies of gold particles, which significantly impacted on the electrochemical characteristics of the PEDOT/Au films. PEDOT/Au assemblies were observed to possess unique topographical features, advantageous charge storage capacity (34.9 ± 2.6 mC cm) and low electrical impedance (30 ± 2 Ω at 1 kHz). Furthermore, PEDOT/Au assemblies were observed to facilitate the outgrowth of neurites in a mixed ventral mesencephalon cell population and promotean increase in the neurons/astrocytes ratio relative to all experimental groups, indicating PEDOT/Au biomimetic neuromorphic assemblies as promising materials in engineering electrically conductive neural interface systems.

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Section: Electrochemical Performancesupporting

confidence: 85%

Fractal form PEDOT/Au assemblies as thin-film neural interface materials

Krukiewicz¹,

Chudy²,

Vallejo-Giraldo³

et al. 2018

Biomed. Mater.

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show abstract

“…To increase the adhesion strength between the PEDOT:PSS layer and the electroplated gold surface, the microelectrodes were selectively etched in 0.05 mol/L iodine solution prior to the electropolymerization process of PEDOT:PSS [ 21 ]. Figure 8 shows the microelectrode surface before the etching step, after the etching step and after the PEDOT:PSS coating process.…”

Section: Resultsmentioning

confidence: 99%

“…50 rpm. To significantly increase the adhesion strength between the PEDOT:PSS layer and the gold layer, the surface of the electroplated gold microelectrodes is partially wet-chemically etched directly prior to the PEDOT:PSS coating [ 21 ]. Using a diluted 0.05 mol/L iodine solution (Grüssing GmbH, Filsum, Germany) and an etching time of 1 min a porous gold surface is created, which allows a mechanically strong bonding of the PEDOT:PSS coating to the gold substrate.…”

Section: Methodsmentioning

confidence: 99%

Silicon-Based Microfabrication of Free-Floating Neural Probes and Insertion Tool for Chronic Applications

et al. 2018

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Bidirectional neural interfaces for multi-channel, high-density recording and electrical stimulation of neural activity in the central nervous system are fundamental tools for neuroscience and medical applications. Especially for clinical use, these electrical interfaces must be stable over several years, which is still a major challenge due to the foreign body response of neural tissue. A feasible solution to reduce this inflammatory response is to enable a free-floating implantation of high-density, silicon-based neural probes to avoid mechanical coupling between the skull and the cortex during brain micromotion. This paper presents our latest development of a reproducible microfabrication process, which allows a monolithic integration of a highly-flexible, polyimide-based cable with a silicon-stiffened neural probe at a high resolution of 1 µm. For a precise and complete insertion of the free-floating probes into the cortex, a new silicon-based, vacuum-actuated insertion tool is presented, which can be attached to commercially available electrode drives. To reduce the electrode impedance and enable safe and stable microstimulation an additional coating with the electrical conductive polymer PEDOT:PSS is used. The long-term stability of the presented free-floating neural probes is demonstrated in vitro and in vivo. The promising results suggest the feasibility of these neural probes for chronic applications.

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“…To improve adhesion onto gold surfaces without using any cross-linker or adhesion layer, Pranti et al [86] performed the deposition of PEDOT:PSS onto an iodine-etched gold surface, which creates a rough porous surface. Then, the electropolymerization of EDOT in presence of PSS allows the formation of the polymer into the pores leading to the formation of a PEDOT:PSS layer with strong mechanical bond.…”

Section: Enhancement Of Adhesion Properties Of Pedot:pssmentioning

confidence: 99%

Fabrication and Use of Organic Electrochemical Transistors for Sensing of Metabolites in Aqueous Media

et al. 2018

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Featured Application: Sensing organic molecules in water.Abstract: This review first recalls the basic functioning principles of organic electrochemical transistors (OECTs) then focuses on the transduction mechanisms applicable to OECTs. Materials constituting the active semiconducting part are reviewed, from the historical conducting polymers (polyaniline, polypyrrole) to the actual gold standard, poly-3,4-ethylenedioxythiophene: polystyrene sulfonic acid (PEDOT:PSS), as well as the methods used to fabricate these transistors. The review then focuses on applications of OECTs for the detection of small molecules and more particularly of metabolites, with a distinction between enzymatic and non-enzymatic transduction pathways. Finally, the few patents registered on the topic of OECT-based biosensors are reviewed, and new tracks of improvement are proposed. applied to biosensing quite early, associated with enzymes [4][5][6]. This is because, due to their functioning mechanism (already identified at the time), they brought into play the same charge carriers as most biological functions, i.e., electrons but also ions, and were therefore sensitive both to electron transfer to/from redox enzymes or ions (e.g., protons) produced from other types of enzymes. This is a characteristic which distinguished them from organic field-effect transistors (OFETs), which started to raise the attention of researchers exactly at the same period (precisely, 1983 for the first polyacetylene-based OFET [7]), and a few years later for applications to gas sensing (halogens, ammonia, oxygen [8-10] or even vapors of H 2 O, NO or H 2 O 2 [11][12][13][14]). However, OFETs never really produced any applicable results in the framework of biosensors in aqueous environment because of high operating voltages, of several tens of volts, which impede any measurements because of water electrolysis. Ion-sensitive organic field-effect transistors (ISOFETs), based on the same working principles of their inorganic counterparts (ISFETs) developed earlier [15,16], solved this problem of high operating potential, the electrolyte being not in direct contact with the semiconductor. However, these devices were confined mostly to protons detection [17][18][19] or, in any case, to charged species.As we show in this review, OECTs use both potentiometry and amperometry in their working principles. In that sense, OECTs are devices that represent a bridge between ISOFETs and classical amperometry, which certainly explains their success. This area of research is very active and several reviews have already been published on OECTs in general, for example by Kergoat et al. [1] or Rivnay et al. [3], or on OECTs applied to biology, for example by Liao and Yan [20], Liao et al. [21], Strakosas et al. [22] or . This present review, after going back to the basic functioning principles, along with details on transductions applicable to OECTs, reviews materials, fabrication techniques and then sensing applications. We focus on the detection of small molecules and more part...

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Highly Stable PEDOT:PSS Coating on Gold Microelectrodes with Improved Charge Injection Capacity for Chronic Neural Stimulation

Cited by 21 publications

References 5 publications

Fractal form PEDOT/Au assemblies as thin-film neural interface materials

Fractal form PEDOT/Au assemblies as thin-film neural interface materials

Silicon-Based Microfabrication of Free-Floating Neural Probes and Insertion Tool for Chronic Applications

Fabrication and Use of Organic Electrochemical Transistors for Sensing of Metabolites in Aqueous Media

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