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Shire DB, Gingerich MD, Wong PI, Skvarla M, Cogan SF, Chen J, Wang W, Rizzo JF. Micro-Fabrication of Components for a High-Density Sub-Retinal Visual Prosthesis. MICROMACHINES 2020; 11:mi11100944. [PMID: 33086504 PMCID: PMC7603138 DOI: 10.3390/mi11100944] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 10/10/2020] [Accepted: 10/13/2020] [Indexed: 01/30/2023]
Abstract
We present a retrospective of unique micro-fabrication problems and solutions that were encountered through over 10 years of retinal prosthesis product development, first for the Boston Retinal Implant Project initiated at the Massachusetts Institute of Technology and at Harvard Medical School’s teaching hospital, the Massachusetts Eye and Ear—and later at the startup company Bionic Eye Technologies, by some of the same personnel. These efforts culminated in the fabrication and assembly of 256+ channel visual prosthesis devices having flexible multi-electrode arrays that were successfully implanted sub-retinally in mini-pig animal models as part of our pre-clinical testing program. We report on the processing of the flexible multi-layered, planar and penetrating high-density electrode arrays, surgical tools for sub-retinal implantation, and other parts such as coil supports that facilitated the implantation of the peri-ocular device components. We begin with an overview of the implantable portion of our visual prosthesis system design, and describe in detail the micro-fabrication methods for creating the parts of our system that were assembled outside of our hermetically-sealed electronics package. We also note the unique surgical challenges that sub-retinal implantation of our micro-fabricated components presented, and how some of those issues were addressed through design, materials selection, and fabrication approaches.
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Affiliation(s)
- Douglas B. Shire
- Bionic Eye Technologies, Inc., Ithaca, NY 14850, USA; (M.D.G.); (P.I.W.)
- Correspondence: ; Tel.: +1-607-339-7085
| | | | - Patricia I. Wong
- Bionic Eye Technologies, Inc., Ithaca, NY 14850, USA; (M.D.G.); (P.I.W.)
| | - Michael Skvarla
- Cornell NanoScale Science and Technology Facility, Ithaca, NY 14853, USA;
| | - Stuart F. Cogan
- Department of Bioengineering, University of Texas, Dallas, Richardson, TX 75080, USA;
| | - Jinghua Chen
- Department of Ophthalmology, University of Florida, Gainesville, FL 32611, USA;
| | - Wei Wang
- Department of Ophthalmology, University of Louisville, Louisville, KY 40292, USA;
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Chen J, Poulaki V, Kim SJ, Eldred WD, Kane S, Gingerich M, Shire DB, Jensen R, DeWalt G, Kaplan HJ, Rizzo JF. Implantation and Extraction of Penetrating Electrode Arrays in Minipig Retinas. Transl Vis Sci Technol 2020; 9:19. [PMID: 32821491 PMCID: PMC7401973 DOI: 10.1167/tvst.9.5.19] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 12/31/2019] [Indexed: 12/12/2022] Open
Abstract
Purpose This work was motivated by the goals of demonstrating methods to fabricate and implant large numbers of penetrating arrays into the retina and the feasibility of extraction. Methods Arrays of inactive, three-dimensional (3D) SU-8 structures were microfabricated onto 13-µm polyimide substrates. Standard vitreoretinal surgical techniques were used with an ab externo approach for subretinal implantation of arrays in 12 mini-pigs. In the first three surgeries, different post-geometries were explored, while a preferred design (128-µm tall, 30-µm diameter, 200-µm spacing) was used for the remaining nine implantations. Two arrays were extracted. Funduscopy, optical coherence tomography (OCT) and immunohistochemistry of the retinae were performed. The unoperated eyes and tissue far from implantation served as controls. A thirteenth pig was implanted with a planar array. Results Ten implant surgeries had no significant complication, and two arrays were successfully extracted. One retinal tear occurred after implantation due to too long posts in an early surgery. In “successful” cases, OCT showed close apposition of the arrays to the retina and integration of the posts, the tops of which were positioned at the junction of the inner plexiform and ganglion cells, without significant gliosis. Conclusions These results provide a proof-of-concept that relatively large numbers of 3D posts can be implanted into, and extracted from, the retina of mini-pigs. Our surgical numbers were relatively small, especially for the extractions, and our conclusions must be viewed with that limitation. Our methods are applicable for human surgeries. Translational Relevance This study provides results of implantation and extraction of relatively large numbers of 3D posts from the retina of minipig eyes. If similar technology were used in humans, a 3D array of this type should lower perceptual thresholds, provide safer long-term stimulation, and perhaps provide better perceptual outcomes.
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Affiliation(s)
- Jinghua Chen
- Department of Ophthalmology, University of Florida, College of Medicine, Gainesville, FL, USA
| | - Vasiliki Poulaki
- Boston VA Healthcare System, Ophthalmology, Jamaica Plain, Boston, MA, USA
| | - Seong-Joon Kim
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Korea
| | | | | | | | | | - Ralph Jensen
- Boston VA Healthcare System, Ophthalmology, Jamaica Plain, Boston, MA, USA
| | - Gloria DeWalt
- Department of Biology, Boston University, Boston, MA, USA
| | - Henry J Kaplan
- Department of Ophthalmology and Visual Sciences, University of Louisville, Louisville, KY, USA
| | - Joseph F Rizzo
- Department of Ophthalmology, Harvard Medical School and the Massachusetts Eye and Ear, Boston, MA, USA
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Xiao Y, Wang Y, Li F, Lin T, Huffman K, Landeros S, Bosse B, Jing Y, Bartsch DU, Thorogood S, Freeman WR, Cheng L. Acute Rabbit Eye Model for Testing Subretinal Prostheses. Transl Vis Sci Technol 2019; 8:20. [PMID: 31602345 PMCID: PMC6779096 DOI: 10.1167/tvst.8.5.20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 07/23/2019] [Indexed: 11/24/2022] Open
Abstract
Purpose Subretinal prostheses are a novel technology for restoring useful vision in patients with retinitis pigmentosa or age-related macular degeneration. We characterize the surgical implantation technique and functional time window of an acute rabbit eye model for testing of human subretinal prostheses. Methods Retinal prostheses were implanted subretinally in 26 rabbits using a two-step technique. Fundus imaging, fluorescein fundus angiography, and optical coherence topography (OCT) were conducted postoperatively from days 1 to 21 to monitor prosthesis positioning and retinal anatomic changes. Results Successful implantation and excellent retina apposition were achieved in 84.6% of the rabbits. OCTs showed the overlying retina at full thickness for the first 2 days after implantation. Histology confirmed intact inner layers of the overlying retina until day 3. Progressive atrophy of the overlying retina was revealed by repeated OCTs; approximately 40% of the retina thickness remained on postoperative days 5 and 6. Conclusions The two-step implantation technique works well for the rabbit eye model with human prostheses. Rabbit retina may be used for acute electrophysiologic testing of a retinal prosthesis, but is unsuitable for chronic studies due to the merangiotic retina and its limited time window of validity. Translational Relevance The improved efficacy in prosthesis surgery using this technique will circumvent the challenges in animal models that provide human-like features critical for the transition into human clinical trials.
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Affiliation(s)
- Ying Xiao
- Department of Ophthalmology, Jacobs Retina Center at Shiley Eye Institute, University of California, San Diego, La Jolla, CA, USA
| | - Yuqin Wang
- Department of Ophthalmology, Jacobs Retina Center at Shiley Eye Institute, University of California, San Diego, La Jolla, CA, USA
| | - Fangting Li
- Department of Ophthalmology, Jacobs Retina Center at Shiley Eye Institute, University of California, San Diego, La Jolla, CA, USA
| | - Tiezhu Lin
- Department of Ophthalmology, Jacobs Retina Center at Shiley Eye Institute, University of California, San Diego, La Jolla, CA, USA
| | - Kristyn Huffman
- Department of Ophthalmology, Jacobs Retina Center at Shiley Eye Institute, University of California, San Diego, La Jolla, CA, USA
| | - Stephanie Landeros
- Department of Ophthalmology, Jacobs Retina Center at Shiley Eye Institute, University of California, San Diego, La Jolla, CA, USA
| | | | - Yi Jing
- Nanovision Biosciences, Inc., La Jolla, CA, USA
| | - Dirk-Uwe Bartsch
- Department of Ophthalmology, Jacobs Retina Center at Shiley Eye Institute, University of California, San Diego, La Jolla, CA, USA
| | | | - William R Freeman
- Department of Ophthalmology, Jacobs Retina Center at Shiley Eye Institute, University of California, San Diego, La Jolla, CA, USA
| | - Lingyun Cheng
- Department of Ophthalmology, Jacobs Retina Center at Shiley Eye Institute, University of California, San Diego, La Jolla, CA, USA
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Leung RT, Nayagam DAX, Williams RA, Allen PJ, Salinas-La Rosa CM, Luu CD, Shivdasani MN, Ayton LN, Basa M, Yeoh J, Saunders AL, Shepherd RK, Williams CE. Safety and efficacy of explanting or replacing suprachoroidal electrode arrays in a feline model. Clin Exp Ophthalmol 2014; 43:247-58. [PMID: 25196241 DOI: 10.1111/ceo.12428] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 08/24/2014] [Indexed: 11/26/2022]
Abstract
BACKGROUND A key requirement for retinal prostheses is the ability for safe removal or replacement. We examined whether suprachoroidal electrode arrays can be removed or replaced after implantation. METHODS Suprachoroidal electrode arrays were unilaterally implanted into 13 adult felines. After 1 month, arrays were surgically explanted (n = 6), replaced (n = 5) or undisturbed (n = 2). The retina was assessed periodically using fundus photography and optical coherence tomography. Three months after the initial implantation, the function of replaced or undisturbed arrays was assessed by measuring the responses of the visual cortex to retinal electrical stimulation. The histopathology of tissues surrounding the implant was examined. RESULTS Array explantation or replacement was successful in all cases. Fundus photography showed localized disruption to the tapetum lucidum near the implant's tip in seven subjects following implantation. Although optical coherence tomography showed localized retinal changes, there were no widespread statistically significant differences in the thickness of the retinal layers or choroid. The distance between the electrodes and retina increased after device replacement but returned to control values within eight weeks (P < 0.03). Staphylomas developed near the scleral wound in five animals after device explantation. Device replacement did not alter the cortical evoked potential threshold. Histopathology showed localized outer nuclear layer thinning, tapetal disruption and pseudo-rosette formation, but the overall retinal morphology was preserved. CONCLUSIONS It is feasible to remove or replace conformable medical grade silicone electrode arrays implanted suprachoroidally. The scleral wound requires careful closure to minimize the risk of staphylomas.
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Affiliation(s)
- Ronald T Leung
- Bionics Institute, Melbourne, Victoria, Australia; Department of Pathology, The University of Melbourne, Melbourne, Victoria, Australia
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Rizzo JF, Shire DB, Kelly SK, Troyk P, Gingerich M, McKee B, Priplata A, Chen J, Drohan W, Doyle P, Mendoza O, Theogarajan L, Cogan S, Wyatt JL. Development of the boston retinal prosthesis. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2012; 2011:3135-8. [PMID: 22255004 DOI: 10.1109/iembs.2011.6090855] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A small, hermetic, wirelessly-controlled retinal prosthesis was developed for pre-clinical studies in Yucatan mini-pigs. The device was implanted on the outside of the eye in the orbit, and it received both power and data wirelessly from external sources. The prosthesis drove a sub-retinal thin-film array of sputtered iridium oxide stimulating electrodes. The implanted device included a hermetic titanium case containing the 16-channel stimulator chip and discrete circuit components. Feedthroughs in the hermetic case connected the chip to secondary power- and data-receiving coils, which coupled to corresponding external power and data coils driven by a power amplifier. Power was delivered by a 500 KHz carrier, and data were delivered by frequency shift keying. Stimulation pulse strength, duration and frequency were programmed wirelessly from an external computer system. Through an 'outbound' telemetry channel, electrode impedances were monitored by an on-board analog to digital converter that sampled the output voltage waveforms. The final assembly was tested in vitro in physiological saline and in vivo in two mini-pigs for up to three months by measuring stimulus artifacts generated by the implant's current drivers.
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Affiliation(s)
- Joseph F Rizzo
- Boston VA Healthcare System, 150 S Huntington Ave, Boston, MA 02130, USA. joseph_rizzo @meei.harvard.edu
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Rizzo JF, Shire DB, Kelly SK, Troyk P, Gingerich M, McKee B, Priplata A, Chen J, Drohan W, Doyle P, Mendoza O, Theogarajan L, Cogan S, Wyatt JL. Overview of the boston retinal prosthesis: challenges and opportunities to restore useful vision to the blind. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2012; 2011:7492-5. [PMID: 22256071 DOI: 10.1109/iembs.2011.6093610] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
A small, hermetic, wirelessly-controlled retinal prosthesis was developed for pre-clinical studies in Yucatan mini-pigs. The device was implanted on the outside of the eye in the orbit, and it received both power and data wirelessly from external sources. The prosthesis drove a sub-retinal thin-film array of sputtered iridium oxide stimulating electrodes. The implanted device included a hermetic titanium case containing the 16-channel stimulator chip and discrete circuit components. Feedthroughs in the hermetic case connected the chip to secondary power- and data-receiving coils, which coupled to corresponding external power and data coils driven by a power amplifier. Power was delivered by a 500 KHz carrier, and data were delivered by frequency shift keying. Stimulation pulse strength, duration and frequency were programmed wirelessly from an external computer system. Through an 'outbound' telemetry channel, electrode impedances were monitored by an on-board analog to digital converter that sampled the output voltage waveforms. The final assembly was tested in vitro in physiological saline and in vivo in two mini-pigs for up to three months by measuring stimulus artifacts generated by the implant's current drivers.
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Affiliation(s)
- Joseph F Rizzo
- Boston VA Healthcare System, 150 S Huntington Ave, Boston, MA 02130, USA.
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Kelly SK, Shire DB, Chen J, Doyle P, Gingerich MD, Cogan SF, Drohan WA, Theogarajan LS, Wyatt JL, Rizzo JF. Communication and Control System for a 15-Channel Hermetic Retinal Prosthesis. Biomed Signal Process Control 2011; 6:356-363. [PMID: 21927618 DOI: 10.1016/j.bspc.2011.05.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A small, hermetic, wirelessy-controlled retinal prosthesis has been developed for pre-clinical studies in Yucatan minipigs. The device was attached conformally to the outside of the eye in the socket and received both power and data wirelessly from external sources. Based on the received image data, the prosthesis drove a subretinal thin-film polyimide array of sputtered iridium oxide stimulating electrodes. The implanted device included a hermetic titanium case containing a 15-channel stimulator and receiver chip and discrete circuit components. Feedthroughs in the hermetic case connected the chip to secondary power- and data-receiving coils, which coupled to corresponding external power and data coils driven by power amplifiers. Power was delivered by a 125 KHz carrier, and data were delivered by amplitude shift keying of a 15.5 MHz carrier at 100 Kbps. Stimulation pulse strength, duration and frequency were programmed wirelessly from an external computer system. The final assembly was tested in vitro in physiological saline and in vivo in two minipigs for up to five and a half months by measuring stimulus artifacts generated by the implant's current drivers.
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Affiliation(s)
- Shawn K Kelly
- Center for Innovative Visual Rehabilitation, Boston VA Healthcare System, 150 South Huntington Avenue, Boston, MA 02130 USA
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Kelly SK, Shire DB, Chen J, Doyle P, Gingerich MD, Cogan SF, Drohan WA, Behan S, Theogarajan L, Wyatt JL, Rizzo JF. A hermetic wireless subretinal neurostimulator for vision prostheses. IEEE Trans Biomed Eng 2011; 58:3197-205. [PMID: 21859595 DOI: 10.1109/tbme.2011.2165713] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
A miniaturized, hermetically encased, wirelessly operated retinal prosthesis has been developed for preclinical studies in the Yucatan minipig, and includes several design improvements over our previously reported device. The prosthesis attaches conformally to the outside of the eye and electrically drives a microfabricated thin-film polyimide array of sputtered iridium oxide film electrodes. This array is implanted into the subretinal space using a customized ab externo surgical technique. The implanted device includes a hermetic titanium case containing a 15-channel stimulator chip and discrete circuit components. Feedthroughs in the case connect the stimulator chip to secondary power and data receiving coils on the eye and to the electrode array under the retina. Long-term in vitro pulse testing of the electrodes projected a lifetime consistent with typical devices in industry. The final assembly was tested in vitro to verify wireless operation of the system in physiological saline using a custom RF transmitter and primary coils. Stimulation pulse strength, duration, and frequency were programmed wirelessly from a Peripheral Component Interconnect eXtensions for Instrumentation (PXI) computer. Operation of the retinal implant has been verified in two pigs for up to five and a half months by detecting stimulus artifacts generated by the implanted device.
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Affiliation(s)
- Shawn K Kelly
- Center for Innovative Visual Rehabilitation, VA Boston Healthcare System, Boston, MA 02130, USA.
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Kusnyerik A, Resch M, Roska T, Karacs K, Gekeler F, Wilke R, Benav H, Zrenner E, Süveges I, Németh J. [Vision restoration with implants in retinal degenerations]. Orv Hetil 2011; 152:537-45. [PMID: 21436016 DOI: 10.1556/oh.2011.29064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Up until now there has been no available treatment for diseases causing the permanent impairment of retinal photoreceptors. Currently the development of the retinal prostheses is the earliest to promise a result that can be implemented in the clinical treatment of these patients. Implants with different operating principles and in various stages of progress are presented in details, highlighting the characteristics, as well as the Hungarian aspects of the development. This survey intends to provide an overview on retinal prostheses, implantable in case of degenerative diseases of the retina, by reviewing and assessing the papers published in relevant journals and based on personal experience. Developments in microelectronics in recent years made it possible and proved to be feasible to replace the degenerated elements in the retina with electrical stimulation. Multiple comparable approaches are running simultaneously. Two types of these implants are directly stimulating the remaining living cells in the retina. Hitherto the finest resolution has been achieved with the subretinal implants. Although the epiretinal implant offer lower resolution, but requires shorter surgery for implantation. Retinal implants in certain retinal diseases are proved to be capable of generating vision-like experiences. A number of types of retinal implants can be expected to appear in clinical practice a few years after the successful conclusion of clinical trials.
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Affiliation(s)
- Akos Kusnyerik
- Semmelweis Egyetem, Általános Orvostudományi Kar, Szemészeti Klinika Budapest.
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