Safe Implantation of a Flexible Electrode Array Into the Eye by ‘Sandwich’ Technique
Jong-Mo SeoC DoddsYan T. WongE. KimJingai ZhouJohn W. MorleyGregg J. SuaningNigel H. LovellS. KimH. Chung
1
Citation
0
Reference
20
Related Paper
Keywords:
Electrode array
Cite
Interfacing
Multielectrode array
Pyramid (geometry)
Cite
Citations (4)
Pipette
Cite
Citations (20)
A flexible multi-electrode array (MEA) with an embedded silicon chip for electrical stimulation of neurons or for recording action potentials has been manufactured and characterized. Possible improvements for medical applications using this novel approach are presented. By connecting and addressing several of these MEAs via a bus system, the number and the density of electrodes can be increased significantly. This is interesting for medical applications such as retinal implants and cochlear implants, and also for deep brain stimulators. Design and fabrication techniques for the multi-electrode array are presented. Finally, first results of mechanical stress tests are shown.
Electrode array
Retinal implant
Cite
Citations (1)
Multielectrode array
Electrode array
Biocompatible material
Plotter
Cite
Citations (137)
Interfacing
Cite
Citations (0)
Retinal Prosthesis
Electrode array
Visual prosthesis
Cite
Citations (0)
Implanted electrodes are the first piece of hardware in an intracortical signals recording pathway. This work presents an improved flexible microwire array electrode for intracortical recordings. Only ready-made materials and general mechanical tools are used to fabricate a microelectrode. The proposed procedure is relatively simple, even for a novice worker to implement in-house. Many key steps in producing a good microwire array electrode are facilitated. These main steps include selecting materials, preparing for fabrication, and assembling the electrode. The assembly of the microwire array electrode includes connecting and positioning PCB pattern, arraying and fixing microwires, and soldering and packaging the electrode. A practiced researcher can assemble the microelectrode in about 2 h and implant it in approximately three. The mass of this assembled microelectrode is 1.96 g. The cost of the materials in the entire array is less than US$1.5, and the array is suitable for implantation in the cortex of rats for invasive studies. In this study, electrochemical impedance spectroscopy is also applied to measure the impedance and the phase between the electrode and the electrolyte, and then to obtain an equivalent circuit. The improved microwire array electrode is adopted to record the intracortical signal of cerebrum. The microwire array electrode can be fabricated and used for multi-site, multiple single-unit recording experiments. Several experimental results are presented, along with applications that demonstrate the feasibility and advantages of the proposed approach.
Electrode array
Multielectrode array
Cite
Citations (8)
Minimally invasive implantation of subdural electrodes can dramatically benefit the patients with various neurological diseases. In modern clinical practice, the implantation procedure of the electrode arrays remains traumatic for patients and increases postoperative infection risk. Here we report a design and insertion technique of thermally activated shape-memory polymer-based electrode array that can recover up to ten times length deformation. The compressed four-centimeter wide array can be easily packed into a three-millimeter diameter tube and subsequently deployed thought five-millimeter opening in a restricted space between a brain phantom and a simulated skull. The mechanical properties of the developed array are comparable to the materials traditionally employed for the purpose, and the electrical and signal recording properties are preserved after shape deformation and recovery. Additionally, the array is biocompatible and exhibits conformability to a curvy brain surface. The results demonstrate that insertion of the electrode array through a small hole into a restricted space similar to subdural cavity is possible, which may inspire future solution of minimal invasive implantation for patients suffering from epilepsy, amyotrophic lateral sclerosis or tetraplegia.
Shape-memory polymer
Electrode array
Cite
Citations (1)
A wirelessly operated, minimally invasive retinal prosthesis was developed for preclinical chronic implantation studies in Yucatan minipig models. The implant conforms to the outer wall of the eye and drives a microfabricated polyimide stimulating electrode array with sputtered iridium oxide electrodes. This array is implanted in the subretinal space using a specially designed ab externo surgical technique that fixes the bulk of the prosthesis to the outer surface of the sclera. The implanted device is fabricated on a host polyimide flexible circuit. It consists of a 15-channel stimulator chip, secondary power and data receiving coils, and discrete power supply components. The completed device is encapsulated in poly(dimethylsiloxane) except for the reference/counter electrode and the thin electrode array. In vitro testing was performed to verify the performance of the system in biological saline using a custom RF transmitter circuit and primary coils. Stimulation patterns as well as pulse strength, duration, and frequency were programmed wirelessly using custom software and a graphical user interface. Wireless operation of the retinal implant has been verified both in vitro and in vivo in three pigs for more than seven months, the latter by measuring stimulus artifacts on the eye surface using contact lens electrodes.
Retinal implant
Visual prosthesis
Cite
Citations (149)