High-density 3D pyramid-shaped microelectrode arrays for brain-machine interface applications

We present, in this paper, a new multichip system aimed toward building an implantable visual intracortical stimulation device. The objective is to deliver energy-optimum pulse patterns to neural sites with needed compliance voltage across high electrode-tissue interface impedance of implantable microelectrodes. The first chip is an energy-efficient stimuli generator (SG), and the second one is a high-impedance microelectrode array driver (MED) output stage. The fourchannel SG produces rectangular, half-sine, plateau-sine, and other types of current pulse with stimulation current ranging from 2.32 to 220 μA per channel. The microelectrode array driver is able to deliver 20 V per anodic or cathodic phase across the microelectrode-tissue interface for ±13 V power supplies. The MED supplies different current levels with the maximum value of 400 μA per input and 100 μA per output channel simultaneously to 8-16 stimulation sites through microelectrodes, connected either in bipolar or monopolar configuration. Both chips receive power via inductive link and data through capacitive coupling. The SG and MED chips have been fabricated in 0.13-μm CMOS and 0.8-μm 5-/20-V CMOS/double-diffused metal-oxidesemiconductor technologies. The measured dc power budgets consumed by low-and mid-voltage chips are 2.56 and 2.1 mW consecutively. The system, modular in architecture, is interfaced with a newly developed platinum-coated pyramidal microelectrode array. In vitro test results with 0.9% phosphate buffer saline show the microelectrode impedance of 70 k at 1 kHz.

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“…For performing in vitro tests, we have interfaced a novel 3-D MEA [17] with the proposed microstimulator. Fig.…”

Section: Resultsmentioning

confidence: 99%

Toward an Energy-Efficient High-Voltage Compliant Visual Intracortical Multichannel Stimulator

Hasanuzzaman

Motlagh

Mounaïm

et al. 2018

IEEE Trans. VLSI Syst.

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“…SEM images of a 7 × 7 matrix of rectangular columns with different heights were acquired after the backside dicing and glassing processes ( Figure 6 a) [ 28 ]. The rectangular columns of the electrodes were converted to sharp needle-shaped tips ( Figure 6 b,c).…”

Section: Resultsmentioning

confidence: 99%

“…A novel masking method was developed to coat the 3D pyramid-shaped MEA. The proposed masking process has several advantages including a single masking step, simpler fabrication process, reducing production time and cost by more than 50%, and a more uniform electrode tip exposure [ 28 ]. In order to improve the electrical properties of the MEA, the tips of the electrodes were coated with Pt following a selective direct growth of CNTs.…”

Section: Introductionmentioning

confidence: 99%

Direct Growth of Carbon Nanotubes on New High-Density 3D Pyramid-Shaped Microelectrode Arrays for Brain-Machine Interfaces

et al. 2016

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Silicon micromachined, high-density, pyramid-shaped neural microelectrode arrays (MEAs) have been designed and fabricated for intracortical 3D recording and stimulation. The novel architecture of this MEA has made it unique among the currently available micromachined electrode arrays, as it has provided higher density contacts between the electrodes and targeted neural tissue facilitating recording from different depths of the brain. Our novel masking technique enhances uniform tip-exposure for variable-height electrodes and improves process time and cost significantly. The tips of the electrodes have been coated with platinum (Pt). We have reported for the first time a selective direct growth of carbon nanotubes (CNTs) on the tips of 3D MEAs using the Pt coating as a catalyzer. The average impedance of the CNT-coated electrodes at 1 kHz is 14 kΩ. The CNT coating led to a 5-fold decrease of the impedance and a 600-fold increase in charge transfer compared with the Pt electrode.

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“…The classic electrode materials are gold and platinum (Bieberich and Anthony 2004 ). While some research aimed to change the geometry of usually planar metal electrodes to utilize pillars, pyramids, "mushrooms,, nails, or needles (Huys et al 2012 ), other investigations experimented with entirely different materials to increase the signal-to-noise ratio of recordings and impedance for stimulation of attached cells (Brüggemann et al 2011 ;Motlagh 2014 ;Hai and Spira 2012 ). Today, titanium nitride and the transparent indium tin oxide are the most abundantly used materials, as they create rough fi lms, which 276 increase the surface area of an electrode for better recording and stimulation (Heer et al 2004 ;Gross et al 1985 ).…”

Section: Mea System For Controlling/monitoring Neuronal Activationmentioning

confidence: 99%

Neural Engineering

2016

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High-density 3D pyramid-shaped microelectrode arrays for brain-machine interface applications

Abstract: ACKNOWLEDGEMENTSThe completion of this dissertation has been an amazing journey filled with many experience from the labs to the real life! I had the opportunity to work under the supervision of truly astonishing individual Prof.

Cited by 5 publications

References 150 publications

Toward an Energy-Efficient High-Voltage Compliant Visual Intracortical Multichannel Stimulator

Toward an Energy-Efficient High-Voltage Compliant Visual Intracortical Multichannel Stimulator

Direct Growth of Carbon Nanotubes on New High-Density 3D Pyramid-Shaped Microelectrode Arrays for Brain-Machine Interfaces

Neural Engineering

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