Limits...
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.


Schematic diagram of the manufacturing process for the guide cannula electrode of the microdialysis probe. (A) The hole of the stainless-steel guide cannula is covered with epoxy. (B) Photosensitive-polyimide is deposited on the guide cannula. (C) Chromium/gold is deposited and recording microelectrodes, hard wiring, and slit are patterned. (D) Photosensitive-polyimide is deposited again. (E) Exposed recording microelectrode and connector sites are patterned. (F) The guide cannula is cut to the optimal length at the slit.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3376501&req=5

Figure 2: Schematic diagram of the manufacturing process for the guide cannula electrode of the microdialysis probe. (A) The hole of the stainless-steel guide cannula is covered with epoxy. (B) Photosensitive-polyimide is deposited on the guide cannula. (C) Chromium/gold is deposited and recording microelectrodes, hard wiring, and slit are patterned. (D) Photosensitive-polyimide is deposited again. (E) Exposed recording microelectrode and connector sites are patterned. (F) The guide cannula is cut to the optimal length at the slit.

Mentions: Figure 2 illustrates the fabrication process for the guide cannula electrode of the microdialysis probe. This process was similar to that of the ECoG and the mesh intracortical electrodes. First, the microdialysis probe was taken apart and the stainless-steel guide cannula (0.4 mm ID, 0.5 mm OD) was removed. The hole of the guide cannula was covered with epoxy (High Super 5, Cemedine Co., Ltd., Tokyo, Japan). This was done to keep impurities out of the guide cannula and prevent the microdialysis membrane from breaking when it is inserted in the guide cannula. Next, in order to insulate the stainless-steel guide cannula, PSPI was spin-coated at 2500 rpm on the curved surface of the guide cannula in an upright position. The PSPI coating was soft-baked at 60°C for 2 min and 100°C for 15 min with the upright position maintained. This process was done for one side of the guide cannula first and then repeated for the other side. The coating was then post-baked by using the same condition as in the process for the ECoG and the mesh intracortical electrodes. A metallization layer of chromium and gold was deposited by vacuum evaporation and structured by using the lift-off technique for individual recording microelectrode sites, interconnect lines, connection pads, and slits near both ends as cutoff marks. An electrodeposited coating (Elecoat EU-XC, Shimizu Co., Ltd., Osaka, Japan) was used as a sacrificial layer. A second PSPI layer with a thickness of about 2 μm was coated and cured by using the same method as for the first PSPI layer. The second PSPI coating was wet-etched to define the recording microelectrode sites and then fully cured to insulate the metallization layer. We used a dicer to cut the guide cannula to the optimal length at the slits (DAD-2H/6T, Disco Corporation, Tokyo, Japan), and soldered the connector to it. Finally, the connector region was covered with black rubber adhesive (Y-902, SOMAY-Q TECHNOLOGY Corporation, Ibaraki, Japan) and the screw cap and microdialysis membrane were assembled.


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

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

Schematic diagram of the manufacturing process for the guide cannula electrode of the microdialysis probe. (A) The hole of the stainless-steel guide cannula is covered with epoxy. (B) Photosensitive-polyimide is deposited on the guide cannula. (C) Chromium/gold is deposited and recording microelectrodes, hard wiring, and slit are patterned. (D) Photosensitive-polyimide is deposited again. (E) Exposed recording microelectrode and connector sites are patterned. (F) The guide cannula is cut to the optimal length at the slit.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 2: Schematic diagram of the manufacturing process for the guide cannula electrode of the microdialysis probe. (A) The hole of the stainless-steel guide cannula is covered with epoxy. (B) Photosensitive-polyimide is deposited on the guide cannula. (C) Chromium/gold is deposited and recording microelectrodes, hard wiring, and slit are patterned. (D) Photosensitive-polyimide is deposited again. (E) Exposed recording microelectrode and connector sites are patterned. (F) The guide cannula is cut to the optimal length at the slit.
Mentions: Figure 2 illustrates the fabrication process for the guide cannula electrode of the microdialysis probe. This process was similar to that of the ECoG and the mesh intracortical electrodes. First, the microdialysis probe was taken apart and the stainless-steel guide cannula (0.4 mm ID, 0.5 mm OD) was removed. The hole of the guide cannula was covered with epoxy (High Super 5, Cemedine Co., Ltd., Tokyo, Japan). This was done to keep impurities out of the guide cannula and prevent the microdialysis membrane from breaking when it is inserted in the guide cannula. Next, in order to insulate the stainless-steel guide cannula, PSPI was spin-coated at 2500 rpm on the curved surface of the guide cannula in an upright position. The PSPI coating was soft-baked at 60°C for 2 min and 100°C for 15 min with the upright position maintained. This process was done for one side of the guide cannula first and then repeated for the other side. The coating was then post-baked by using the same condition as in the process for the ECoG and the mesh intracortical electrodes. A metallization layer of chromium and gold was deposited by vacuum evaporation and structured by using the lift-off technique for individual recording microelectrode sites, interconnect lines, connection pads, and slits near both ends as cutoff marks. An electrodeposited coating (Elecoat EU-XC, Shimizu Co., Ltd., Osaka, Japan) was used as a sacrificial layer. A second PSPI layer with a thickness of about 2 μm was coated and cured by using the same method as for the first PSPI layer. The second PSPI coating was wet-etched to define the recording microelectrode sites and then fully cured to insulate the metallization layer. We used a dicer to cut the guide cannula to the optimal length at the slits (DAD-2H/6T, Disco Corporation, Tokyo, Japan), and soldered the connector to it. Finally, the connector region was covered with black rubber adhesive (Y-902, SOMAY-Q TECHNOLOGY Corporation, Ibaraki, Japan) and the screw cap and microdialysis membrane were assembled.

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.