Advertisement

In Situ Characterization of Stimulating Microelectrode Arrays: Study of an Idealized Structure Based on Argus II Retinal implants

  • Vincent Kandagor
  • Carlos J. Cela
  • Charlene A. Sanders
  • Elias Greenbaum
  • Gianluca Lazzi
  • David D. Zhou
  • Richard Castro
  • Sanjay Gaikwad
  • Jim Little
Chapter
Part of the Biological and Medical Physics, Biomedical Engineering book series (BIOMEDICAL)

Abstract

The development of a retinal prosthesis for artificial sight includes a study of the factors affecting the structural and functional stability of chronically implanted microelectrode arrays. Although neuron depolarization and propagation of electrical signals have been studied for nearly a century, the use of multielectrode stimulation as a proposed therapy to treat blindness is a frontier area of modern ophthalmology research. Mapping and characterizing the topographic information contained in the electric field potentials and understanding how this information is transmitted and interpreted in the visual cortex is still very much a work in progress. In order to characterize the electrical field patterns generated by the device, an in vitro prototype that mimics several of the physical and chemical parameters of the in vivo visual implant device was fabricated. We carried out multiple electrical measurements in a model “eye,” beginning with a single electrode, followed by a 9-electrode array structure, both idealized components based on the Argus II retinal implants. Correlating the information contained in the topographic features of the electric fields with psychophysical testing in patients may help reduce the time required for patients to convert the electrical patterns into graphic signals.

Keywords

Electrode Array Recording Electrode Stimulate Electrode Vitreous Humor Charge Injection 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Notes

Acknowledgements

This work was supported by the Office of Biological and Environmental Research, U.S. Department of Energy. Oak Ridge National Laboratory is managed by UT-Battelle, LLC for the U.S. Department of Energy under Contract DE-AC05-00OR22725.

References

  1. 1.
    Humayun MS, Weiland JD, Fujii GY et al (2003) Visual perception in a blind subject with a chronic microelectronic retinal prosthesis. Vision Research 43: 2573–2581.CrossRefGoogle Scholar
  2. 2.
    Santos A, Humayun MS, de Juan E, Jr. et al. (1997) Preservation of the inner retina in retinitis pigmentosa. A morphometric analysis. Archives of Ophthalmology 115:511–555.Google Scholar
  3. 3.
    Palanker D, Vankov A, Huie P et al. (2007) High-resolution opto-electronic retinal prosthesis: physical limitations and design. In Artificial Sight: Basic Research, Biomedical Engineering, and Clinical Advances, Biological and Medical Physics-Biomedical Engineering, MS Humayun, JD Weiland, G Chader, E Greenbaum eds., New York: Springer, pp. 255–278.Google Scholar
  4. 4.
    Shah S, Hines A, Zhou D et al. (2007) Electrical properties of retinal-electrode interface. Journal of Neural Engineering 4:S24–S29.CrossRefGoogle Scholar
  5. 5.
    Colodetti L, Weiland JD, Colodetti S et al. (2007) Pathology of damaging electrical stimulation in the retina. Experimental Eye Research 85:23–33.CrossRefGoogle Scholar
  6. 6.
    Kummer MP, Abbott JJ, Dinser S et al. (2007) Artificial vitreous humor for in vitro experiments. Conf Proc IEEE Eng Med Biol Soc, pp. 6407–6410.Google Scholar
  7. 7.
    Chirila TV, Hong Y, Dalton PD et al. (1998) The use of hydrophilic polymers as artificial vitreous. Progress in Polymer Science 23:475–508.CrossRefGoogle Scholar
  8. 8.
    Sanders CA, Nagler EJ, Zhou D et al. (2007) Dynamic Interactions of retinal prosthesis electrodes with neural tissue and materials science in electrode design. In Artificial Sight:Basic Research, Biomedical Engineering, and Clinical Advances, Biological and Medical Physics-Biomedical Engineering, MS Humayun, JD Weiland, G Chader, E Greenbaum eds., New York: Springer, pp. 209–226.Google Scholar
  9. 9.
    Weiland JD, Humayun MS, Liu W et al. (2002) Stimulating neural activity. In Handbook of Neuroprosthetic Methods, WE Finn, PG LoPresti eds., Boca Raton: CRC Press, pp. 75–94.Google Scholar
  10. 10.
    Suesserman MF, Spelman FA, Rubinstein JT (1991) In vitro measurement and characterization of current-density profiles produced by nonrecessed, simple recessed, and radially varying recessed stimulating electrodes. IEEE Transactions on Biomedical Engineering 38:401–408.CrossRefGoogle Scholar
  11. 11.
    Ameri H, Weiland JD, Humayun MS (2007) Biological considerations for an intraocular retinal prosthesis. In Artificial Sight:Basic Research, Biomedical Engineering, and Clinical Advances, Biological and Medical Physics-Biomedical Engineering, MS Humayun, JD Weiland, G Chader, E Greenbaum eds., New York: Springer, pp. 1–30.Google Scholar
  12. 12.
    Chu A, Morris K, Agazaryan A et al. (2007) In vitro determination of stimulus-induced pH changes in visual prostheses. In Artificial Sight: Basic Research, Biomedical Engineering, and Clinical Advances, Biological and Medical Physics-Biomedical Engineering, MS Humayun, JD Weiland, G Chader, E Greenbaum eds., New York: Springer, pp. 227–242.Google Scholar
  13. 13.
    Hench LL (1975) Prosthetic implant materials. Annual Review of Materials Science 5:279–300.CrossRefGoogle Scholar
  14. 14.
    Brummer SB, Turner MJ (1975) Electrical-stimulation of nervous-system – principle of safe charge injection with noble-metal electrodes. Bioelectrochemistry and Bioenergetics 2:13–25.CrossRefGoogle Scholar
  15. 15.
    Humayun MS, Scribner D, Justus B (2001) Intraocular retinal prosthesis test device. Proc. 23rd annual EMBS international conference, Istanbul, Turkey, pp. 3430–3435.Google Scholar
  16. 16.
    Zhou DM (2005) Platinum electrode and method for manufacturing the same. US patent 6,974,533.Google Scholar
  17. 17.
    Troelstra A, Garcia CA (1975) Electrical response of human eye to sinusoidal light stimulation. IEEE Transactions on Biomedical Engineering 22:369–378.CrossRefGoogle Scholar
  18. 18.
    Lazzi G et al (2008) unpublished data.Google Scholar
  19. 19.
    Schmidt S, Cela CJ, Singh V, Weiland J, Humayun MS, Lazzi G (2007) Computational Modeling of Electromagnetic and Thermal Effects for a Dual-Unit Retinal Prosthesis: Inductive Telemetry, Temperature Increase, and Current Densities in the Retina, In Artificial Sight:Basic Research, Biomedical Engineering,and Clinical Advances, Biological and Medical Physics-Biomedical Engineering, M. S. Humayun, J. D. Weiland, G. Chader and E. Greenbaum eds., New York: Springer, 2007, pp. 279–306.Google Scholar

Copyright information

© Springer Science+Business Media, LLC 2009

Authors and Affiliations

  • Vincent Kandagor
    • 1
  • Carlos J. Cela
    • 2
  • Charlene A. Sanders
    • 1
  • Elias Greenbaum
    • 1
  • Gianluca Lazzi
    • 2
  • David D. Zhou
    • 3
  • Richard Castro
    • 3
  • Sanjay Gaikwad
    • 3
  • Jim Little
    • 3
  1. 1.Molecular Bioscience and Biotechnology, Chemical Sciences DivisionOak Ridge National LaboratoryOak RidgeUSA
  2. 2.Department of Electrical and Computer EngineeringNorth Carolina State UniversityRaleighUSA
  3. 3.Second Sight Medical Products, Inc.SylmarUSA

Personalised recommendations