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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.


Auditory evoked potentials recorded from the auditory cortex of an anesthetized rat by the ECoG electrode. The data shown here are averages across 100 stimulus presentations. (A-C) Auditory stimuli were 50 ms broadband noise at 20-, 40-, and 80-dB SPL, and (D-F) 50 ms pure tones of 1, 4, and 16 kHz at 80-dB SPL (D-F). Each set of data represent the same alignment as that in the right-top picture, which shows the alignment of 16-channel recording microelectrodes.
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Figure 6: Auditory evoked potentials recorded from the auditory cortex of an anesthetized rat by the ECoG electrode. The data shown here are averages across 100 stimulus presentations. (A-C) Auditory stimuli were 50 ms broadband noise at 20-, 40-, and 80-dB SPL, and (D-F) 50 ms pure tones of 1, 4, and 16 kHz at 80-dB SPL (D-F). Each set of data represent the same alignment as that in the right-top picture, which shows the alignment of 16-channel recording microelectrodes.

Mentions: As shown in Figure 6, the proposed shape of the guide cannula electrode for the microdialysis probe was achieved by using PSPI-based microfabrication technology. No delamination of the PSPI and no breakage were observed during the fabrication process. This implies that the coated PSPI tightly adhered to the curved surface of the guide cannula. The ideal coating thickness was about 10 μm, but it was about 2 μm after the post-baking. This indicated that some of the spin-coated PSPI flowed to the bottom due to the upright position in the coating and curing processes, but the upright position allowed uniform coating on the cylindrical surface. The coating thickness of 2 μm also showed stable physical properties of electric and mechanical insulation. The results for the guide cannula electrode showed that our PSPI-based photolithographic patterning is not limited to a flat surface.


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

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

Auditory evoked potentials recorded from the auditory cortex of an anesthetized rat by the ECoG electrode. The data shown here are averages across 100 stimulus presentations. (A-C) Auditory stimuli were 50 ms broadband noise at 20-, 40-, and 80-dB SPL, and (D-F) 50 ms pure tones of 1, 4, and 16 kHz at 80-dB SPL (D-F). Each set of data represent the same alignment as that in the right-top picture, which shows the alignment of 16-channel recording microelectrodes.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 6: Auditory evoked potentials recorded from the auditory cortex of an anesthetized rat by the ECoG electrode. The data shown here are averages across 100 stimulus presentations. (A-C) Auditory stimuli were 50 ms broadband noise at 20-, 40-, and 80-dB SPL, and (D-F) 50 ms pure tones of 1, 4, and 16 kHz at 80-dB SPL (D-F). Each set of data represent the same alignment as that in the right-top picture, which shows the alignment of 16-channel recording microelectrodes.
Mentions: As shown in Figure 6, the proposed shape of the guide cannula electrode for the microdialysis probe was achieved by using PSPI-based microfabrication technology. No delamination of the PSPI and no breakage were observed during the fabrication process. This implies that the coated PSPI tightly adhered to the curved surface of the guide cannula. The ideal coating thickness was about 10 μm, but it was about 2 μm after the post-baking. This indicated that some of the spin-coated PSPI flowed to the bottom due to the upright position in the coating and curing processes, but the upright position allowed uniform coating on the cylindrical surface. The coating thickness of 2 μm also showed stable physical properties of electric and mechanical insulation. The results for the guide cannula electrode showed that our PSPI-based photolithographic patterning is not limited to a flat surface.

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.