Electrical impedance, electrochemistry, mechanical stiffness, and hardness tunability in glassy carbon MEMS μECoG electrodes

Kassegne, Sam; Vomero, Maria; Gavuglio, Roberto; Hirabayashi, Mieko; Özyilmaz, Emre; Nguyen, Sebastien Doan Ky Nam; Rodríguez, Jesús López; Niekerk, Pieter van; Khosla, Ajit

doi:10.1016/j.mee.2014.11.013

Cited by 40 publications

(63 citation statements)

References 39 publications

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“…Therefore, the possibility to control the temperature-induced structural transformation is critically important for the fabrication of the glassy carbon products with desired functional features. It is essential to note that novel glassy carbon applications, such as micro-electro-mechanical systems [13,14], that can be used for medical prostheses [15,16] require comprehensive characterization of the properties-structure relationships at both, bulk-and nanoscale level. But up to now, the knowledge on how the manufacturing temperature, that is, how the internal structure affects the properties of glassy carbons is insufficient.…”

Section: Introductionmentioning

confidence: 99%

Evolution of glassy carbon under heat treatment: correlation structure–mechanical properties

et al. 2017

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In order to accommodate an increasing demand for glassy carbon products with tailored characteristics, one has to understand the origin of their structure-related properties. In this work, through the use of high-resolution transmission electron microscopy, Raman spectroscopy, and electron energy loss spectroscopy it has been demonstrated that the structure of glassy carbon at different stages of the carbonization process resembles the curvature observed in fragments of nanotubes, fullerenes, or nanoonions. The measured nanoindentation hardness and reduced Young's modulus change as a function of the pyrolysis temperature from the range of 600-2500°C and reach maximum values for carbon pyrolyzed at around 1000°C. Essentially, the highest values of the mechanical parameters for glassy carbon manufactured at that temperature can be related to the greatest amount of non-planar sp 2 -hybridized carbon atoms involved in the formation of curved graphene-like layers. Such complex labyrinth-like structure with sp 2 -type bonding would be rigid and hard to break that explains the glassy carbon high strength and hardness.

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Section: Introductionmentioning

confidence: 99%

Evolution of glassy carbon under heat treatment: correlation structure–mechanical properties

et al. 2017

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“…Here, since ρ = 1.29 g/m³ is the mass density, c = 0.71 J/(Kg) is the specific energy and k = 0.084 W/Km the thermal conductivity (information provided by the supplier Speciality Coating Systems-SCS), it can be assumed that when the laser pulse repetition doubles, the temperature at the parylene C interface doubles as well. Because the temperature is a crucial factor during every carbonization process 14 , the laser parameters should be modulated and optimized to yield crystalline graphitic structures. To achieve that and have a better understanding of the influence that the laser pulse frequency has on the structural and behavioral changes of our carbon electrodes, we then directly compared two groups of devices: the P20 group, made by using an infrared nanosecond pulsed laser with a working frequency of 20 kHz, and the P40 group, made using the same laser but with a working frequency of 40 kHz.…”

Section: Resultsmentioning

confidence: 99%

“…Neural interfaces indeed play a critical role in chronic applications, where they have to outlast the highly humid and oxidative body environment without undergoing delamination or corrosion and thus losing their functionality over time 7–13 . Among all, carbon was proved to be the material with the highest potential to simultaneously serve as biomaterial for recording nerve cells activity, electrically stimulating them and, in addition, for selectively detecting the presence of neurotransmitters and other electrically active biomolecules 14–18 . However, the batch fabrication of carbon electrode arrays and their integration into micromachining technologies for flexible substrates represent key challenges that often limit the usage and the investigation of carbon as electrode material for neural interfaces.…”

Section: Introductionmentioning

confidence: 99%

Graphitic Carbon Electrodes on Flexible Substrate for Neural Applications Entirely Fabricated Using Infrared Nanosecond Laser Technology

Vomero

Oliveira

Ashouri

et al. 2018

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Neural interfaces for neuroscientific research are nowadays mainly manufactured using standard microsystems engineering technologies which are incompatible with the integration of carbon as electrode material. In this work, we investigate a new method to fabricate graphitic carbon electrode arrays on flexible substrates. The devices were manufactured using infrared nanosecond laser technology for both patterning all components and carbonizing the electrode sites. Two laser pulse repetition frequencies were used for carbonization with the aim of finding the optimum. Prototypes of the devices were evaluated in vitro in 30 mM hydrogen peroxide to mimic the post-surgery oxidative environment. The electrodes were subjected to 10 million biphasic pulses (39.5 μC/cm2) to measure their stability under electrical stress. Their biosensing capabilities were evaluated in different concentrations of dopamine in phosphate buffered saline solution. Raman spectroscopy and x-ray photoelectron spectroscopy analysis show that the atomic percentage of graphitic carbon in the manufactured electrodes reaches the remarkable value of 75%. Results prove that the infrared nanosecond laser yields activated graphite electrodes that are conductive, non-cytotoxic and electrochemically inert. Their comprehensive assessment indicates that our laser-induced carbon electrodes are suitable for future transfer into in vivo studies, including neural recordings, stimulation and neurotransmitters detection.

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“…71 In this work, we use a carbon nanoparticle ink to print the interfacing electrode material due to its electrochemical stability, wide electrochemical water window, and low impedance for electrical sensing and stimulation of cellular activity. [72][73][74][75][76][77][78][79] We shed light on the process required for ink-jet printing high-resolution MEAs, feedlines, and passivation layers on a soft substrate. Functional mircoelectrode arrays are printed on PDMS, agarose, and even gelatin-based substrates including candies (gummy bears).…”

Section: Introductionmentioning

confidence: 99%

Printed microelectrode arrays on soft materials: from PDMS to hydrogels

et al. 2018

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Microelectrode arrays (MEAs) provide promising opportunities to study electrical signals in neuronal and cardiac cell networks, restore sensory function, or treat disorders of the nervous system. Nevertheless, most of the currently investigated devices rely on silicon or polymer materials, which neither physically mimic nor mechanically match the structure of living tissue, causing inflammatory response or loss of functionality. Here, we present a new method for developing soft MEAs as bioelectronic interfaces. The functional structures are directly deposited on PDMS-, agarose-, and gelatin-based substrates using ink-jet printing as a patterning tool. We demonstrate the versatility of this approach by printing high-resolution carbon MEAs on PDMS and hydrogels. The soft MEAs are used for in vitro extracellular recording of action potentials from cardiomyocyte-like HL-1 cells. Our results represent an important step toward the design of next-generation bioelectronic interfaces in a rapid prototyping approach.npj Flexible Electronics (2018) 2:15 ;

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Electrical impedance, electrochemistry, mechanical stiffness, and hardness tunability in glassy carbon MEMS μECoG electrodes

Cited by 40 publications

References 39 publications

Evolution of glassy carbon under heat treatment: correlation structure–mechanical properties

Evolution of glassy carbon under heat treatment: correlation structure–mechanical properties

Graphitic Carbon Electrodes on Flexible Substrate for Neural Applications Entirely Fabricated Using Infrared Nanosecond Laser Technology

Printed microelectrode arrays on soft materials: from PDMS to hydrogels

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