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Photosensitive-polyimide based method for fabricating various neural electrode architectures.

Kato YX, Furukawa S, Samejima K, Hironaka N, Kashino M - Front Neuroeng (2012)

Bottom Line: After characterizing PSPI's properties for micromachining processes, we successfully designed and fabricated various neural electrodes even on a non-flat substrate using only one PSPI as an insulation material and without the time-consuming dry etching processes.In vivo neural recordings using anesthetized rats demonstrated that these electrodes can be used to record neural activities repeatedly without any breakage and mechanical failures, which potentially promises stable recordings for long periods of time.These successes make us believe that this PSPI-based fabrication is a powerful method, permitting flexible design, and easy optimization of electrode architectures for a variety of electrophysiological experimental research with improved neural recording performance.

View Article: PubMed Central - PubMed

Affiliation: Brain Science Institute, Tamagawa University, Machida Tokyo, Japan.

ABSTRACT
An extensive photosensitive-polyimide (PSPI)-based method for designing and fabricating various neural electrode architectures was developed. The method aims to broaden the design flexibility and expand the fabrication capability for neural electrodes to improve the quality of recorded signals and integrate other functions. After characterizing PSPI's properties for micromachining processes, we successfully designed and fabricated various neural electrodes even on a non-flat substrate using only one PSPI as an insulation material and without the time-consuming dry etching processes. The fabricated neural electrodes were an electrocorticogram (ECoG) electrode, a mesh intracortical electrode with a unique lattice-like mesh structure to fixate neural tissue, and a guide cannula electrode with recording microelectrodes placed on the curved surface of a guide cannula as a microdialysis probe. In vivo neural recordings using anesthetized rats demonstrated that these electrodes can be used to record neural activities repeatedly without any breakage and mechanical failures, which potentially promises stable recordings for long periods of time. These successes make us believe that this PSPI-based fabrication is a powerful method, permitting flexible design, and easy optimization of electrode architectures for a variety of electrophysiological experimental research with improved neural recording performance.

No MeSH data available.


Related in: MedlinePlus

Photographs of the fabricated ECoG electrode, mesh intracortical electrode, and guide cannula electrode of the microdialysis electrode. (A) Overview of the fabricated neural electrode. (B) Magnified view of recording microelectrodes or connector sites. (C) Back face of the connector side of the ECoG electrode. (D) Magnified view of a through-hole for connector pins in the ECoG electrode. (E) Back face of connector side fitted with soldering pins of connector in the ECoG electrode.
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Figure 4: Photographs of the fabricated ECoG electrode, mesh intracortical electrode, and guide cannula electrode of the microdialysis electrode. (A) Overview of the fabricated neural electrode. (B) Magnified view of recording microelectrodes or connector sites. (C) Back face of the connector side of the ECoG electrode. (D) Magnified view of a through-hole for connector pins in the ECoG electrode. (E) Back face of connector side fitted with soldering pins of connector in the ECoG electrode.

Mentions: The three different architectures of PSPI-based multichannel flexible neural electrodes-ECoG, mesh intracortical, and guide cannula were successfully designed and fabricated. Photographs of the three fabricated neural electrodes are shown in Figure 4. Table 3 lists the sizes in the photomask designs and fabricated neural electrodes, which show the overall shrinkage and expansion effect of the fabrication. In the fabrication process, we did not observe delamination between the bottom PSPI layer and the chromium-coated glass substrate nor in the metal layer sandwiched by the PSPI. The thin and complicated mesh structure in the mesh intracortical electrode was lifted off from the wafer by coating a protective resist. No breakage in the mesh structure was observed. This indicates a stable fabrication process at lower cost with improvement of process yields. The processing time was about 12–15 h in our fabrication environment (excluding the time for designing and fabricating the photomasks).


Photosensitive-polyimide based method for fabricating various neural electrode architectures.

Kato YX, Furukawa S, Samejima K, Hironaka N, Kashino M - Front Neuroeng (2012)

Photographs of the fabricated ECoG electrode, mesh intracortical electrode, and guide cannula electrode of the microdialysis electrode. (A) Overview of the fabricated neural electrode. (B) Magnified view of recording microelectrodes or connector sites. (C) Back face of the connector side of the ECoG electrode. (D) Magnified view of a through-hole for connector pins in the ECoG electrode. (E) Back face of connector side fitted with soldering pins of connector in the ECoG electrode.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3376501&req=5

Figure 4: Photographs of the fabricated ECoG electrode, mesh intracortical electrode, and guide cannula electrode of the microdialysis electrode. (A) Overview of the fabricated neural electrode. (B) Magnified view of recording microelectrodes or connector sites. (C) Back face of the connector side of the ECoG electrode. (D) Magnified view of a through-hole for connector pins in the ECoG electrode. (E) Back face of connector side fitted with soldering pins of connector in the ECoG electrode.
Mentions: The three different architectures of PSPI-based multichannel flexible neural electrodes-ECoG, mesh intracortical, and guide cannula were successfully designed and fabricated. Photographs of the three fabricated neural electrodes are shown in Figure 4. Table 3 lists the sizes in the photomask designs and fabricated neural electrodes, which show the overall shrinkage and expansion effect of the fabrication. In the fabrication process, we did not observe delamination between the bottom PSPI layer and the chromium-coated glass substrate nor in the metal layer sandwiched by the PSPI. The thin and complicated mesh structure in the mesh intracortical electrode was lifted off from the wafer by coating a protective resist. No breakage in the mesh structure was observed. This indicates a stable fabrication process at lower cost with improvement of process yields. The processing time was about 12–15 h in our fabrication environment (excluding the time for designing and fabricating the photomasks).

Bottom Line: After characterizing PSPI's properties for micromachining processes, we successfully designed and fabricated various neural electrodes even on a non-flat substrate using only one PSPI as an insulation material and without the time-consuming dry etching processes.In vivo neural recordings using anesthetized rats demonstrated that these electrodes can be used to record neural activities repeatedly without any breakage and mechanical failures, which potentially promises stable recordings for long periods of time.These successes make us believe that this PSPI-based fabrication is a powerful method, permitting flexible design, and easy optimization of electrode architectures for a variety of electrophysiological experimental research with improved neural recording performance.

View Article: PubMed Central - PubMed

Affiliation: Brain Science Institute, Tamagawa University, Machida Tokyo, Japan.

ABSTRACT
An extensive photosensitive-polyimide (PSPI)-based method for designing and fabricating various neural electrode architectures was developed. The method aims to broaden the design flexibility and expand the fabrication capability for neural electrodes to improve the quality of recorded signals and integrate other functions. After characterizing PSPI's properties for micromachining processes, we successfully designed and fabricated various neural electrodes even on a non-flat substrate using only one PSPI as an insulation material and without the time-consuming dry etching processes. The fabricated neural electrodes were an electrocorticogram (ECoG) electrode, a mesh intracortical electrode with a unique lattice-like mesh structure to fixate neural tissue, and a guide cannula electrode with recording microelectrodes placed on the curved surface of a guide cannula as a microdialysis probe. In vivo neural recordings using anesthetized rats demonstrated that these electrodes can be used to record neural activities repeatedly without any breakage and mechanical failures, which potentially promises stable recordings for long periods of time. These successes make us believe that this PSPI-based fabrication is a powerful method, permitting flexible design, and easy optimization of electrode architectures for a variety of electrophysiological experimental research with improved neural recording performance.

No MeSH data available.


Related in: MedlinePlus