Mechanical and electrical evaluation for the long-term stability of implanted 3D retinal microelectrode

Abstract

In this paper, the mechanical and electrical characteristics of 3D microelectrode are presented to provide the long-term stability of the implanted microelectrode. As the dimensions of the microelectrode become smaller, the microelectrode can be easily damaged by mechanical pressure and overinjected electric charge. In order to avoid these destructions, allowable mechanical and electrical stress should be determined. Experiments for durability evaluation are set up and performed to measure the mechanical force and safe charge injection limit. The result of the experiments shows that the allowable mechanical force in vertical and horizontal direction is 0.8165 N and 0.2068 N, respectively. In the charge injection test, it is observed that the density of injected charge is a prior factor in microelectrode dissolution rather than the total amount of injected charge.

Electrical Characterization of 3D Au Microelectrodes for Use in Retinal Prostheses

“…As a different approach, we have been developing 3D microelectrodes since 2006. We have presented results on the fabrication [ 10 , 11 ], long-term biostability [ 12 ], and enhanced electrical/mechanical characteristics [ 12 , 13 ] of such devices. Other researchers have also reported results on 3D electrode technology [ 14 ].…”

Selection and biocompatibility of electrode in spinal cord stimulator system

“…The first kind is the flexible microneedle electrode (MEAs), which is generally made of poly-p-xylene [10] and polyimide [11]. Another one is the 3-D MEAs which is microneedle electrode made of rigid materials, for silicon [12]、 gold [13]、nickel [14]、titanium [15]、steel [16]、polymethyl methacrylate [17]. 3-D MEAs with high-aspect-ratio needles have also been utilized in neural electrical stimulation and recording, for they can contact closely with tissues or even penetrate into tissues to get more effective and accurate electrical conduction.…”

Contactless Liquid Sensing Technique Using a Quartz Oscillator

“…(16,(32)(33)(34)(35)(36)(37) 3D electrodes are expected to approach the target cells in the retina more closely than 2D electrodes. Also, the flexible polyimide substrate is adapted for conformal attachment to the spherical structure of the eye.…”

“…Mechanical evaluation was performed to characterize the maximum vertical and horizontal stresses. (37) The threshold force for the mechanical durability in the vertical direction can be seen in Fig. 4(a).…”