Limits...
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.

Show MeSH

Related in: MedlinePlus

The fabrication process flow stimulating MEA.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3376591&req=5

f4-sensors-12-03131: The fabrication process flow stimulating MEA.

Mentions: The stimulating MEA is fabricated with polyimide (PI-2525, HD Micro Systems, Tokyo, Japan), Ti, and Au at the Inter-university Semiconductor Research Center (Seoul, Republic of Korea) using the microelectromechanical systems (MEMS) technology. All materials are biocompatible [28,29]. A stimulating microelectrode has a 30 μm diameter, and a reference microelectrode has a 70 μm diameter. They are separated 600 μm apart from each other. The fabrication process is described in Figure 4. First, SiO2 is deposited on Si substrate for releasing device at the final step. Polyimide (8 μm) is spin coated and cured as a lower base layer. Titanium and gold are deposited and patterned for the microelectrodes and conductive lines. Then, polyimide (8 μm) is spin coated again, and patterned for the site opening openings and base shaping. Finally, using hydrofluoric acid solution, the polyimide-substrate MEA is released from the substrate.


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)

The fabrication process flow stimulating MEA.
© Copyright Policy
Related In: Results  -  Collection

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

f4-sensors-12-03131: The fabrication process flow stimulating MEA.
Mentions: The stimulating MEA is fabricated with polyimide (PI-2525, HD Micro Systems, Tokyo, Japan), Ti, and Au at the Inter-university Semiconductor Research Center (Seoul, Republic of Korea) using the microelectromechanical systems (MEMS) technology. All materials are biocompatible [28,29]. A stimulating microelectrode has a 30 μm diameter, and a reference microelectrode has a 70 μm diameter. They are separated 600 μm apart from each other. The fabrication process is described in Figure 4. First, SiO2 is deposited on Si substrate for releasing device at the final step. Polyimide (8 μm) is spin coated and cured as a lower base layer. Titanium and gold are deposited and patterned for the microelectrodes and conductive lines. Then, polyimide (8 μm) is spin coated again, and patterned for the site opening openings and base shaping. Finally, using hydrofluoric acid solution, the polyimide-substrate MEA is released from the substrate.

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