April 2010
Volume 51, Issue 13
Free
ARVO Annual Meeting Abstract  |   April 2010
Enhanced Microelectrodes for Retinal Stimulation
Author Affiliations & Notes
  • K.-I. Koo
    Electrical Engneering and Computer Science, Seoul National University College of Engineering, Automation and Systems Research Institute / Inter-university Semiconductor Research Institute, Seoul, Republic of Korea
    Nano Artificial Vision Research Center, Seoul, Republic of Korea
  • S. Lee
    Nano Artificial Vision Research Center, Seoul, Republic of Korea
    Electrical Engneering and Computer Science, Seoul National University College of Engineering, Automation and Systems Research Institute / Inter-University Semiconductor Research Institute, Seoul, Republic of Korea
  • J.-W. Ban
    Nano Artificial Vision Research Center, Seoul, Republic of Korea
    Electrical Engneering and Computer Science, Seoul National University College of Engineering, Automation and Systems Research Institute / Inter-University Semiconductor Research Institute, Seoul, Republic of Korea
  • H.-Y. Jeong
    Nano Artificial Vision Research Center, Seoul, Republic of Korea
    Electrical Engneering and Computer Science, Seoul National University College of Engineering, Automation and Systems Research Institute / Inter-University Semiconductor Research Institute, Seoul, Republic of Korea
  • H. Park
    Nano Artificial Vision Research Center, Seoul, Republic of Korea
    Electrical Engneering and Computer Science, Seoul National University College of Engineering, Automation and Systems Research Institute / Inter-University Semiconductor Research Institute, Seoul, Republic of Korea
  • S.-J. Hong
    Nano Artificial Vision Research Center, Seoul, Republic of Korea
    Electrical Engneering and Computer Science, Seoul National University College of Engineering, Automation and Systems Research Institute / Inter-University Semiconductor Research Institute, Seoul, Republic of Korea
  • S. H. Bae
    Nano Artificial Vision Research Center, Seoul, Republic of Korea
    Ophthalmology, Seoul National University School of Medicine, Seoul, Republic of Korea
  • J.-M. Seo
    Nano Artificial Vision Research Center, Seoul, Republic of Korea
    Ophthalmology, Seoul National University School of Medicine, Seoul, Republic of Korea
  • H. Chung
    Nano Artificial Vision Research Center, Seoul, Republic of Korea
    Ophthalmology, Seoul National University School of Medicine, Seoul, Republic of Korea
  • D. D. Cho
    Nano Artificial Vision Research Center, Seoul, Republic of Korea
    Electrical Engneering and Computer Science, Seoul National University College of Engineering, Automation and Systems Research Institute / Inter-University Semiconductor Research Institute, Seoul, Republic of Korea
  • Footnotes
    Commercial Relationships  K.-I. Koo, None; S. Lee, None; J.-W. Ban, None; H.-Y. Jeong, None; H. Park, None; S.-J. Hong, None; S.H. Bae, None; J.-M. Seo, None; H. Chung, None; D.D. Cho, None.
  • Footnotes
    Support  Korea Health 21 R & D Project A050251 supported by MIHWAF
Investigative Ophthalmology & Visual Science April 2010, Vol.51, 3042. doi:https://doi.org/
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    • Get Citation

      K.-I. Koo, S. Lee, J.-W. Ban, H.-Y. Jeong, H. Park, S.-J. Hong, S. H. Bae, J.-M. Seo, H. Chung, D. D. Cho; Enhanced Microelectrodes for Retinal Stimulation. Invest. Ophthalmol. Vis. Sci. 2010;51(13):3042. doi: https://doi.org/.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose: : This paper presents an enhanced microelectrode with varying arrowhead shapes for retinal stimulation. These microelectrodes have arrowhead shapes with varying heights for contour-conformity to target retinal cells. Compared with our previous microelectrode in 2009, these microelectrodes have additional wrapping-layers around the posts, which we found crucially important to withstand the shear stress during implant surgery.

Methods: : Theses microelectrode is fabricated using the microelectromechanical systems (MEMS) technology. The base of each microelectrode is defined by SiO2 layer patterning on a (100) single crystalline Si. The height of post is determined by deep RIE. Alkaline wet etch reveals 8 {111} planes to result in uncompleted octahedron structure. The final structure is an octahedron positioned upon post, resembling an arrowhead shape. Subsequently, Au is electroplated to fill the fabricated mold. The exterior layer of electroplated metal serves as an interface with target cells. After surface polishing, a ring shape pattern around the electroplated electrode is vertically etched. This ring shape pattern works as polyimide wrapping-layer mold. After polyimide body layer is poured and cured, the interconnective metal multi-layers and polyimide intermediate layers are patterned for high density microelectrode array. Finally, the Si substrate is etched away using SF6 from the opposite side. After fabrication, electrical characterization including interface impedance is evaluated. Mechanical robustness is tested by implantation into the rabbit eye.

Results: : The fabricated microelectrode has arrowhead-shaped microelectrodes with the wrapping-layer. The base plane of each electrode is a 30 ~ 100 µm diameter circle. The total height of each electrode is approximately 70 ~ 120 µm. The interface impedance shows a magnitude of 116.6 kilo-Ohm and a phase shift of -71.33 ° at 1 kHz in saline medium at room temperature. Fabricated MEA showed good integrity during surgical manipulation.

Conclusions: : A new type of MEA was fabricated using the MEMS technology and evaluated at in vivo environment. This result indicates that it is possible to implement approximately 1.5 times higher density arrays for larger scale integration.

Keywords: retina • electrophysiology: non-clinical • transplantation 
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