In-Vitro and In-Vivo Electrical Characteristics of a Penetrating
Microelectrode Array for Optic Nerve Electrical Stimulation
SUI Xiao-hong (隋晓红), SHAO Yi-bin (邵轶彬), LI Li-ming (李丽明)
CHAI Xin-yu (柴新禹), REN Qiu-shi (任秋实)
(1. Institute of Laser Medicine and Biophotonics,
Shanghai Jiaotong Universtiy, Shanghai 200240, China;
2. Department of Biomedical Engineering, Peking University, Beijing
100871, China)
Abstract 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.
Received: 16 September 2010
Published: 29 October 2011
the National Natural Science Foundation of China (Nos. 30700217 and 60971102) and the National Basic Research Program (973) of China (Nos. 2011CB707502 and 2011CB707505)
Corresponding Authors:
SUI Xiao-hong (隋晓红),
E-mail: renqsh@sjtu.edu.cn
