Can subretinal microphotodiodes successfully replace degenerated photoreceptors?

Zrenner, Eberhart; Stett, Alfred; Weiß, Stefan; Aramant, Robert B.; Guenther, Elke; Köhler, Konrad; Miliczek, K.-D.; Seiler, Magdalene J.; Haemmerle, H.

doi:10.1016/s0042-6989(98)00312-5

Cited by 267 publications

(155 citation statements)

References 27 publications

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“…Inkjet printing typically ensures better morphology and inter-membrane connectivity, and thus the conductivity of the printed pattern is higher compared to the drop cast samples as confirmed by the data presented here. On the other hand, the resistivity of drop cast C/T-Graphene, IPAGraphene and NMP-Graphene was found to be~10 4 times lower when compared to the MoS 2 dispersions, with values of~0.18, 0.43, and~1.1 Ω cm, respectively, for the three dispersions.…”

Section: Biocompatibility Analysismentioning

confidence: 89%

“…3 Retinal prosthetic devices may be viable as a vision-recovery methodology to restore vision through electrical stimulation. 4,5 Another approach to combat AMD is via the use of artificially implantable photodetectors that are physically placed on the retina. This approach, while promising, suffers from issues of Si substrate rigidity, 6,7 where retinal cells migrate to fill the empty space between the implant and retinal pigment epithelium (RPE), which leads to the formation of scar tissue and cell reorganization in the various layers of the retina.…”

Section: Introductionmentioning

confidence: 99%

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Biocompatible, large-format, inkjet printed heterostructure MoS2-graphene photodetectors on conformable substrates

et al. 2017

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An inkjet printed, biocompatible, heterostructure photodetector is described that was constructed using inks of photo-active molybdenum disulfide (MoS 2 ) and electrically conducting graphene which facilitated charge collection of the photocarriers. The importance of such devices stems from their potential utility in age-related-macular degeneration, which is a condition where the photosensitive retinal tissue degrades with aging, eventually compromising vision. The absence of effective therapeutic remedies for patients with this disorder has motivated the development of such devices to restore some degree of visual function. Inkjet printed, flexible prosthetic devices offer design simplicity where additive manufacturing can enable large format, low-cost arrays. The biocompatible inkjet printed two-dimensional heterojunction devices were photoresponsive to broadband incoming radiation in the visible regime, and the photocurrent I ph scaled proportionally with the incident light intensity, exhibiting a photoresponsivity R~0.30 A/W. This is 10 3 times higher compared to prior reports, and detectivity D was calculated to be~3.6 × 10 10 Jones. Straindependent measurements were also conducted with bending, indicating the feasibility of such devices printed on flexible substrates. Drop cast and printed CT-MoS 2 inks were characterized using techniques, such as Raman spectroscopy, photoluminescence measurements and scanning electron microscopy. Both mouse embryonic fibroblast and human esophageal fibroblast were used for the biocompatibility analysis for inks drop cast on two types of flexible substrates, polyethylene terephthalate and polyimide. The biocompatibility of inks formed using two-dimensional graphene and MoS 2 on polyimide substrates was extremely high, in excess of 98% for mouse embryonic fibroblast.

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Section: Biocompatibility Analysismentioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Biocompatible, large-format, inkjet printed heterostructure MoS2-graphene photodetectors on conformable substrates

et al. 2017

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“…(4)(5)(6) Also, these results support that the approach of restoring vision by electrical stimulation of the surviving neurons using neural prosthetic devices may be viable as a vision-recovery methodology in retinal degenerative diseases. (7,8) The electrical stimulation typically involves a biphasic current waveform for the purpose of driving a constant current through the tissue followed by the reverse current to maintain charge balance.…”

Section: Introductionmentioning

confidence: 99%

Fabrication and Evaluation of Silicon Nanowire Photodetectors on Flexible Substrate for Retinal Prosthetic System

Lee

Jung

Park

et al. 2012

Sensors and Materials

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Retinal degenerative diseases result in a progressive degeneration of photoreceptors in the retina and eventually lead to complete blindness. In this study, we develop a novel silicon nanowire photodetector on a flexible substrate to replace the function of photoreceptors on the retina and restore vision for the blind. An extremely high surfaceto-volume-ratio characteristic of the nanowire enables the development of highly sensitive photonic sensors. Therefore, a nanowire-based photodetector can be used as a stand-alone retinal stimulation system without an external camera. The fabricated silicon nanowire photodetector is measured to have an average photoresponsivity of 1×10 4 A/W in a wide range of light intensities and wavelengths. Also, the optical characteristics of the silicon nanowire photodetector are well maintained on a flexible substrate, which is verified by comparing the photosensitivity before and after the substrate transfer from a rigid form to a flexible form. To evaluate the mechanical durability of the flexible silicon nanowire photodetector, mechanical bending tests are performed. The optical performance of the flexible photodetector is well preserved during bending for 200 times. The presented performance evaluation results show that the proposed nanowire-based photodetector can be used for the implementation of the retinal prosthetic system. The results of this proposed novel method can point the way to a revolutionary break-through in artificial retina research.206

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“…In the cases, photoreceptors are degenerated, however the rest of the neural tissues of the retina are still alive. To recover the vision, visual prosthesis by electrical stimulation of the remaining retinal layer has been discussed [5] [6].…”

Section: Introductionmentioning

confidence: 99%

System implementation of a CMOS vision chip for visual recovery

Uehara

Furumiya

et al. 2003

Sensors and Camera Systems for Scientific, Industrial, and Digital Photography Applications IV

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We have developed a CMOS vision chip, an image sensor with pixel-level signal processing, to replace photoreceptor cells in the retina. In this paper, we describe a pixel-level signal processing, which is to control on the stimulus waveform and the amount of the electrical injection charge.Our CMOS vision chip is an array of a pixel, which consists of a photo detector, a pulse shaper, and a current stimulus circuit. The photo detector circuit generates a pulse frequency modulated (PFM) pulse, which frequency is proportional to the intensity of the incoming light [1] [2]. The PFM photo detector is also modified to restrict the maximum frequency of PFM pulse signal for safety neural stimulation [3].The PFM pulse signal should be converted into suitable waveform for efficient neural stimulation. We have employed a pulse shaper to generate one stimulus pulse from one PFM pulse. The pulse parameters (i.e., pulse duration, polarity, etc) of the output pulse signal are controlled by the external signal.For the electrical neural stimulus, the stimulus intensity is given by the amount of the electrical injection charge. The amount of the injection charge should be enough to evoke a phosphene but should be low to avoid the damage of the retinal tissue caused by the excess charge injection. In our prototyped CMOS vision chip, the stimulus current amplitude is used to control the amount of charge. The 6-bit binary-weighted digital-to-analog converter (DAC) with 2µA resolution is used to control the stimulus current amplitude.

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Can subretinal microphotodiodes successfully replace degenerated photoreceptors?

Cited by 267 publications

References 27 publications

Biocompatible, large-format, inkjet printed heterostructure MoS2-graphene photodetectors on conformable substrates

Biocompatible, large-format, inkjet printed heterostructure MoS2-graphene photodetectors on conformable substrates

Fabrication and Evaluation of Silicon Nanowire Photodetectors on Flexible Substrate for Retinal Prosthetic System

System implementation of a CMOS vision chip for visual recovery

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