Mechanical characterization of neural electrodes based on PDMS-parylene C-PDMS sandwiched system

Henle, Christian; Hassler, Christina; Köhler, Friedrich; Schüettler, Martin

doi:10.1109/iembs.2011.6090142

Cited by 15 publications

(12 citation statements)

References 8 publications

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“…PDMS offers good insulation, vibration absorption, good adaptability to tissue's deformation due to excellent elasticity (Wu et al, 1999 ; Kim et al, 2011 ; Minev et al, 2015 ; Alt et al, 2016 ), diffusional resistance to contamination solutes (Wu et al, 1999 ), good optical transparency (Jeong et al, 2015 ), hardly observed degradation (Alt et al, 2016 ), lower foreign body response (Bae et al, 2014 ), as well as low cost and availability. The most notable quality of PDMS is its superior, FDA-approved biocompatibility (Henle et al, 2011a ; Bae et al, 2014 ) for chronic implants (USP class VI). It is one of the few packaging materials that have been tested for long-term implantation (Brindley et al, 1986 ; Schiavone et al, 2018 ).…”

Section: Packaging and Substrate 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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Section: Packaging and Substrate Materialsmentioning

confidence: 99%

A Review: Electrode and Packaging Materials for Neurophysiology Recording Implants

Yang

Gong

2021

Front. Bioeng. Biotechnol.

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“…For this study a laser-based manufacturing process was developed in order to create tracks individually coated with parylene C. An additional polymer besides the silicon rubber should benefit both, the mechanical and the electrical properties of the array. In contrast to the intermediate parylene layer in [5], arrays with coated integrated tracks spare at least three silicone layers compared to our state-ofthe-art method. Thus the whole electrode array remains more flexible while the fragile metal tracks are individually protected.…”

Section: Introductionmentioning

confidence: 78%

“…3. For the meander design an opening angle θ of 60° was chosen in accordance with actual electrode designs [5]. Other dimensions for the specimens were: Straight coating width w3 = 1.1 mm, track width w1 = 150 µm, metal foil thickness d1 = 12.5 µm and coating thickness d2 = 10 µm.…”

Section: Mechanical Testsmentioning

confidence: 99%

“…However they were still not robust enough for the rough handling during implantation, attributable to the fact that the very soft silicone substrate does not provide enough mechanical protection for the delicate metal tracks. The introduction of an either laser-or chemically structured parylene C layer turned out to be a promising step for enhancing the mechanical strength of the arrays [5]. An example of this state-of-the-art manufacturing is depicted in Figure 1.…”

Section: Introductionmentioning

confidence: 98%

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Parylene-coated metal tracks for neural electrode arrays - Fabrication approaches and improvements utilizing different laser systems

Köhler

Schüettler

2012

2012 Annual International Conference of the IEEE Engineering in Medicine and Biology Society

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In the past we developed a method for the fabrication of neural electrodes based on laser-structuring metal foil to form tracks and electrode sites within a silicone rubber substrate. Here, this process was refined by an additional coating of the laser-patterned metal tracks to improve their mechanical properties. Parylene C has been found to be the coating material of choice due to excellent electrical and mechanical characteristics and its well known biocompatibility. An almost ten times increased tensile strength compared to uncoated tracks could be achieved. Investigating the electrical properties of parylene C and silicone rubber attested both materials excellent insulating capabilities by withstanding voltages of more than 400 V(DC) for layer thicknesses as intended to be used in electrode array fabrication (some 10 µm). This paper outlines the feasibility of the manufacturing process using a 1064 nm Nd:YAG laser in the nanosecond pulse regime. However, an improvement of the whole processing was demonstrated when a 355 nm Nd:YVO(4) laser in the picosecond regime is used. Benefits of this short pulse duration range from ablating materials independent of their optical properties to increased manufacturing speed and superior processing quality.

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“…Laser fabricated electrode arrays are thicker (several 100 µm) than thin-film electrode arrays (several 10 µm) and thus only the later come into consideration for intrafascicular electrode arrays. Reasons for the increased thickness lie within the general greater thickness of the used materials (metal foils: 25 µm, sputtered platinum: 300 nm) as well as the fact that nanosecond laser technology melts the boundaries of the metal foil, which then needs additional silicone rubber and supplementary layers to provide mechanical strength [4]. These problems can be addressed with new shortpulse laser technology that allows for smaller feature size, higher integration density and new base materials like Parylene C that already has approval of the US Food and Drug Administration [5].…”

Section: Introductionmentioning

confidence: 99%

Fabrication of flat electrodes utilizing picosecond laser manufacturing technology: Preliminary study for fabrication of a novel transverse intrafascicular multichannel electrode

Mueller

Köhler

Ordonez

et al. 2014

2014 IEEE 19th International Functional Electrical Stimulation Society Annual Conference (IFESS)

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Over the last decade we developed methods for the fabrication of laser-structured electrode arrays for neural engineering. For these electrode arrays a metal foil was structured with a 1064 nm Nd:YAG laser in the nanosecond pulse regime and placed within a silicone rubber substrate. Due to process restrictions the individual electrode sites are not in plane with the upper layer of the silicone rubber. Here, a new laser in the picosecond regime (355 nm Nd:YVO 4 ) was used for laser-structuring. This allowed the fabrication of a novel electrode array out of a 25 µm thick sheet of MP35N metal with thinned-down and buried tracks as well as fixations for the electrode sites and contact pads. For the opening of the single electrodes two different processes, hatching and cutting, have been tested. Due to the interaction of the laser with the metal hatched electrodes had an increased surface area which was investigated with electrochemical measurements. The individual thicknesses of the layers were measured with a novel way of directly laser cutting the electrodes and measuring under a light microscope.

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Mechanical characterization of neural electrodes based on PDMS-parylene C-PDMS sandwiched system

Cited by 15 publications

References 8 publications

A Review: Electrode and Packaging Materials for Neurophysiology Recording Implants

A Review: Electrode and Packaging Materials for Neurophysiology Recording Implants

Parylene-coated metal tracks for neural electrode arrays - Fabrication approaches and improvements utilizing different laser systems

Fabrication of flat electrodes utilizing picosecond laser manufacturing technology: Preliminary study for fabrication of a novel transverse intrafascicular multichannel electrode

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