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A novel in vitro sensing configuration for retinal physiology analysis of a sub-retinal prosthesis.

Koo KI, Lee S, Yee JH, Ryu SB, Kim KH, Goo YS, Cho DI - Sensors (Basel) (2012)

Bottom Line: This paper presents a novel sensing configuration for retinal physiology analysis, using two microelectrode arrays (MEAs).Results show that the geometrical relation between the stimulation microelectrode locations and the response locations seems very low.These results provide useful guidelines for developing a sub-retinal prosthesis.

View Article: PubMed Central - PubMed

Affiliation: Inter-university Semiconductor Research Center, Automation System Research Institute, School of Electrical Engineering and Computer Science, Seoul National University, Seoul 151-744, Korea. kkin76@snu.ac.kr

ABSTRACT
This paper presents a novel sensing configuration for retinal physiology analysis, using two microelectrode arrays (MEAs). In order to investigate an optimized stimulation protocol for a sub-retinal prosthesis, retinal photoreceptor cells are stimulated, and the response of retinal ganglion cells is recorded in an in vitro environment. For photoreceptor cell stimulation, a polyimide-substrate MEA is developed, using the microelectromechanical systems (MEMS) technology. For ganglion cell response recording, a conventional glass-substrate MEA is utilized. This new sensing configuration is used to record the response of retinal ganglion cells with respect to three different stimulation methods (monopolar, bipolar, and dual-monopolar stimulation methods). Results show that the geometrical relation between the stimulation microelectrode locations and the response locations seems very low. The threshold charges of the bipolar stimulation and the monopolar stimulation are in the range of 10~20 nC. The threshold charge of the dual-monopolar stimulation is not obvious. These results provide useful guidelines for developing a sub-retinal prosthesis.

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Related in: MedlinePlus

Fixture for stimulation MEA. (a) Upper thick part with MEA on polyimide (shown upside down). (b) Lower thin part placed on top to thick part (shown upside down).
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f2-sensors-12-03131: Fixture for stimulation MEA. (a) Upper thick part with MEA on polyimide (shown upside down). (b) Lower thin part placed on top to thick part (shown upside down).

Mentions: The stimulating MEA is microfabricated using polyimide, Ti, and Au. In general, polyimide films float in water. For fixation of the developed MEA on polyimide, a jig is fabricated, using aluminum (the lower thin part) and stainless steel (the upper thick part), as shown in Figure 2. The MEA on polyimide is placed between the lower thin part and the upper thick part. The lower thin part is 200 μm thick, and protrusion in the upper thick part is 150 μm thick. Therefore, if the lower thin part is used, the height from the recording MEA to the stimulating MEA is 200 μm. If the lower thin part is not used, the height from the recording MEA to the stimulating MEA is about 150 μm. The polyimide isolation layer is very thin (∼8 μm). The stimulating MEA with the customized jigs dips into the ACSF medium in the recording MEA chamber, where the isolated retinal patch is attached. Note that these pieces have a center opening for alignment. Figure 3 shows the experimental setup.


A novel in vitro sensing configuration for retinal physiology analysis of a sub-retinal prosthesis.

Koo KI, Lee S, Yee JH, Ryu SB, Kim KH, Goo YS, Cho DI - Sensors (Basel) (2012)

Fixture for stimulation MEA. (a) Upper thick part with MEA on polyimide (shown upside down). (b) Lower thin part placed on top to thick part (shown upside down).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3376591&req=5

f2-sensors-12-03131: Fixture for stimulation MEA. (a) Upper thick part with MEA on polyimide (shown upside down). (b) Lower thin part placed on top to thick part (shown upside down).
Mentions: The stimulating MEA is microfabricated using polyimide, Ti, and Au. In general, polyimide films float in water. For fixation of the developed MEA on polyimide, a jig is fabricated, using aluminum (the lower thin part) and stainless steel (the upper thick part), as shown in Figure 2. The MEA on polyimide is placed between the lower thin part and the upper thick part. The lower thin part is 200 μm thick, and protrusion in the upper thick part is 150 μm thick. Therefore, if the lower thin part is used, the height from the recording MEA to the stimulating MEA is 200 μm. If the lower thin part is not used, the height from the recording MEA to the stimulating MEA is about 150 μm. The polyimide isolation layer is very thin (∼8 μm). The stimulating MEA with the customized jigs dips into the ACSF medium in the recording MEA chamber, where the isolated retinal patch is attached. Note that these pieces have a center opening for alignment. Figure 3 shows the experimental setup.

Bottom Line: This paper presents a novel sensing configuration for retinal physiology analysis, using two microelectrode arrays (MEAs).Results show that the geometrical relation between the stimulation microelectrode locations and the response locations seems very low.These results provide useful guidelines for developing a sub-retinal prosthesis.

View Article: PubMed Central - PubMed

Affiliation: Inter-university Semiconductor Research Center, Automation System Research Institute, School of Electrical Engineering and Computer Science, Seoul National University, Seoul 151-744, Korea. kkin76@snu.ac.kr

ABSTRACT
This paper presents a novel sensing configuration for retinal physiology analysis, using two microelectrode arrays (MEAs). In order to investigate an optimized stimulation protocol for a sub-retinal prosthesis, retinal photoreceptor cells are stimulated, and the response of retinal ganglion cells is recorded in an in vitro environment. For photoreceptor cell stimulation, a polyimide-substrate MEA is developed, using the microelectromechanical systems (MEMS) technology. For ganglion cell response recording, a conventional glass-substrate MEA is utilized. This new sensing configuration is used to record the response of retinal ganglion cells with respect to three different stimulation methods (monopolar, bipolar, and dual-monopolar stimulation methods). Results show that the geometrical relation between the stimulation microelectrode locations and the response locations seems very low. The threshold charges of the bipolar stimulation and the monopolar stimulation are in the range of 10~20 nC. The threshold charge of the dual-monopolar stimulation is not obvious. These results provide useful guidelines for developing a sub-retinal prosthesis.

Show MeSH
Related in: MedlinePlus