Abstract: The Chinese C-Sight team aims to restore
vision to blind patients by means of stimulating the optic nerve
with a penetrating microelectrode array. A biocompatible,
implantable microwire array was developed having four
platinum-iridium shafts, each 100 µm in diameter. This
penetrating microwire array is described in this paper, including
its fabrication techniques and its in-vitro electrical
characteristics. Every set of four shafts was spaced 0.4 mm from
center to center, comprising two short shafts that were 0.3 mm long
and two that were 0.9 mm long. This design was intended to
stimulate ganglion cell axons at different depths within the optic
nerve. In-vitro electrochemical impedance testing results showed
that the impedance at 1 kHz ranged from 8 to 10 kΩ at room
temperature. The voltage responses of the arrays to current pulse
stimulation indicated a charge-injection capacity of
210 µC/cm2. Finally, in-vivo acute animal experiments
showed that the amplitude of the electrically evoked potentials
(EEPs) measured in primary visual cortex could be as large as
100 μV upon direct stimulation of the optic nerve.
SUI Xiao-hong (隋晓红),
. In-Vitro and In-Vivo Electrical Characteristics of a Penetrating
Microelectrode Array for Optic Nerve Electrical Stimulation[J]. Journal of Shanghai Jiaotong University(Science), 2011
, 16(5)
: 614
-619
.
DOI: 10.1007/s12204-011-1198-0
[1] Dobelle W H, Mladejovsky M G. Phosphenes produced by electrical
stimulation of human occipital cortex, and their application to the
development of a prosthesis for the blind [J]. The Journal of
Physiology, 1974, 243(2): 553-576.
[2] Troyk P, Bak M, Berg J, et al. A model for intracortical visual prosthesis
research [J]. Artificial Organs, 2003, 27(11):
1005-1015.
[3] Chow A Y, Chow V Y. Subretinal electrical stimulation of the rabbit
retina [J]. Neuroscience Letter, 1997, 225(1): 13-16.
[4] Zrenner E, Miliczek K D, Gabel V P, et al. The development of subretinal
microphotodiodes for replacement of degenerated photoreceptors [J].
Ophthalmic Research, 1997, 29(5): 269-280.
[5] Humayun M S, Weiland J D, Fujii G Y, et al. Visual perception in a blind
subject with a chronic microelectronic retinal prosthesis [J].
Vision Research, 2003, 43(24): 2573-2581.
[6] Rizzo J F, Wyatt J, Loewenstein J, et al. Methods and perceptual thresholds
for short-term electrical stimulation of human retina with
microelectrode arrays [J]. Investigative Ophthalmology
and Visual Science, 2003, 44(12): 5355-5361.
[7] Veraart C, Raftopoulos C, Mortimer J T, et al. Visual sensations produced by
optic nerve stimulation using an implanted self-sizing spiral cuff
electrode [J]. Brain Research, 1998, 813(1): 181-186.
[8] Brelen M E, Duret F, Gerard B, et al. Creating a meaningful visual perception
in blind volunteers by optic nerve stimulation [J]. Journal of
Neural Engineering, 2005, 2(1): 22-28.
[9] Sakaguchi H, Fujikado T, Fang X Y, et al. Transretinal electrical stimulation
with a suprachoroidal multichannel electrode in rabbit eyes[J].
Japanese Journal of Ophthalmology, 2004, 48(3): 256-261.
[10] Fang X Y, Sakaguchi H, Fujikado T, et al. Direct stimulation of optic nerve
by electrodes implanted in optic disc of rabbit eyes [J].
Graefe's Archive for Clinical and Experimental Ophthalmology, 2005,
243(1): 49-56.
[11] Weiland J D, Liu W, Humayun M S. Retinal
prosthesis [J]. Biomedical Engineering, 2005, 7(1):
361-401.
[12] Pernkopf W, Sagl M, Fafilek G. Applications of microelectrodes in
impedance spectroscopy [J]. Solid State Ionics, 2005,
176(25-28): 2031-2036.
[13] Merrill D R, Bikson M, Jefferys J G R. Electrical stimulation of
excitable tissue: Design of efficacious and safe protocols [J].
Journal of Neuroscience Methods, 2005, 141(2): 171-198.
[14] Geddes L A. Historical evolution of circuit models for the
electrode-electrolyte interface [J]. Annals of Biomedical
Engineering, 1997, 25(1): 1-14.
[15] Weiland J D, Anderson D J, Humayun M S. In vitro electrical properties
for iridium oxide versus titanium nitride stimulating electrodes
[J]. IEEE Transations on Biomedical Engineering, 2002,
49(12): 1574-1579.
[16] Walter P, Heimann K. Evoked cortical potentials after electrical
stimulation of the inner retina in rabbits [J]. Graefe's
Archive for Clinical and Experimental Ophthalmology, 2000,
238(4): 315-318.
[17] Nadig M N. Development of a silicon retinal implant: Cortical evoked
potentials following focal stimulation of the rabbit retina with
light and electricity [J]. Clinical Neurophysiology, 1999,
110(9): 1545-1553.
[18] Fang X, Sakaguchi H, Fujikado T, et al. Direct stimulation of optic nerve by
electrodes implanted in optic disc of rabbit eyes [J].
Graefe' s Archive for Clinical and Experimental Ophthalmology,
2005, 243(1): 49-56.
[19] Brummer S B, Robblee L S, Hambrecht F T. Criteria for selecting
electrodes for electrical stimulation: Theoretical and practical
considerations [J]. Annals of the New York Academy of
Sciences, 1983, 405(1): 159-171.
