ARTIFICIAL RETINAL IMPLANT

• US 20080288067A1
• Filed: 05/12/2008
• Published: 11/20/2008
• Est. Priority Date: 05/10/2007
• Status: Active Grant

• Current Assignee: NewCyte, Inc. (Natcore Technology, Inc.)
• Original Assignee: NewCyte, Inc. (Natcore Technology, Inc.)
• Inventors: Flood, Dennis J.
• Granted Patent: US 8,433,417 B2
• Time in Patent Office: Days
• US Class Current: 623/6.63
• CPC Class Codes: A61F 2250/0043 differing in electric properties, e.g. in electrical conductivity, in galvanic properties
• CPC Class Codes: A61N 1/0543 Retinal electrodes
• CPC Class Codes: A61N 1/36046 of the eye
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• CPC Class Codes: H10K 30/352 the inorganic nanostructures being nanotubes or nanowires, e.g. CdTe nanotubes in P3HT polymer
• CPC Class Codes: H10K 30/87 Light-trapping means
• CPC Class Codes: H10K 39/32 Organic image sensors
• CPC Class Codes: H10K 85/225 comprising substituents

Abstract

Improved photosensing devices and methods are disclosed. Such devices and methods have application, among other things, as retinal implants and in imaging devices. In one embodiment, an exemplary retinal implant can include an array of photoreceptors adapted for positioning in the eye. Each photoreceptor can include a core, for example a carbon nanostructure, and a shell. The shell can include a light-responsive layer, and in many cases, the light-responsive layer can be formed of two semiconductor layers forming a heterojunction. The photoreceptors can be adapted to generate an electric field in response to incident light so as to stimulate a retinal neuron in its vicinity. The photoreceptors can be micron-sized or nano-sized, and can be arranged in densities similar to the density of rods and cones in the human eye. In one embodiment, an exemplary sensor for an imaging device can include a plurality of photosensors disposed on a substrate. Each photosensor can include a carbon nanostructure, a light-responsive layer coating at least a portion of the carbon nanostructure. The nanostructure and the light-responsive layer can be coupled to a set of contacts such that an electrical signal (e.g., voltage or current) developed across the contacts can represent the detection of light incident thereon and can correspond to a pixel in an image.

Claims

1. A retinal implant, comprising:

a plurality of photoreceptors adapted for positioning in the eye, each of said photoreceptors comprising a core including a carbon nanostructure and a shell including a light-responsive semiconducting material,

wherein said photoreceptors are adapted to generate an electric field in response to incident light so as to cause an action potential in at least one retinal neuron.

2. The retinal implant of claim 1, wherein said plurality of photoreceptors are adapted for implantation in the retina.

3. The retinal implant of claim 1, wherein said photoreceptors have tubular structures with widths in a range of about 1 nm to about 10,000 nm.

4. The retinal implant of claim 1, wherein said carbon nanostructure comprises a carbon nanotube.

5. The retinal implant of claim 4, wherein said carbon nanotube comprises any of a single wall or a multi-wall carbon nanotube.

6. The retinal implant of claim 1, further comprising a substrate to which said photoreceptors are coupled.

7. The retinal implant of claim 6, wherein said photoreceptors are arranged in a two-dimensional array over a surface of said substrate.

8. The retinal implant of claim 7, wherein said photoreceptors exhibit a surface density in a range of about 10⁹/mm² to about 10³/mm².

9. An implantable photoreceptor, comprising:

a carbon nanostructure;

a light-responsive layer coating at least a portion of a surface of the carbon nanostructure,

wherein the light-responsive layer is effective to generate, in response to light incident thereon, an electric field external to the photoreceptor suitable to induce an action potential in at least one neuron.

10. The implantable photoreceptor of claim 9, wherein the light-responsive layer includes a first layer disposed on the carbon nanostructure and a second layer disposed on the first layer to form a junction therewith, the junction including a depletion region.

11. The implantable photoreceptor of claim 10, wherein at least one of the first and second layer comprises a semiconductor material.

12. The implantable photoreceptor of claim 10, wherein the first layer and second layer comprise semiconductor materials of differing conductivity types.

13. The implantable photoreceptor of claim 10, wherein at least one of the first and second layers comprises at least one of a Group IV semiconductor, a Group III-V semiconductor, a Group II-VI semiconductor, and a Group I-III-VI semiconductor.

14. The implantable photoreceptor of claim 9, wherein the light-responsive layer is effective to generate, in response to light incident thereon, an electric charge in a portion of the photoreceptor, the electric charge producing an electric field external to the photoreceptor suitable to induce an action potential in a neuron.

15. The implantable photoreceptor of claim 9, wherein the electric field has a strength in a range of about 1,000 Volts/cm to about 100,000 Volts/cm.

16. The implantable photoreceptor of claim 9, wherein the electric charge is generated in at least one of the carbon nanostructure and the light-responsive layer.

17. The implantable photoreceptor of claim 9, wherein the light-responsive layer coats at least a portion of the surface of the nanostructure such that a coated end of the nanostructure has a radius of curvature of less than about 10⁻

6 cm.

18. The implantable photoreceptor of claim 9, wherein the carbon nanostructure has a tapered end to enhance an electric field produced therefrom.

19. The implantable photoreceptor of claim 9, further comprising a substrate supporting the carbon nanostructure.

20. The implantable photoreceptor of claim 19, wherein the substrate is disk-shaped.

21. The implantable photoreceptor of claim 19, wherein the substrate is annular.

22. The implantable photoreceptor of claim 9, wherein each carbon nanostructure comprises a carbon nanotube.

23. The implantable photoreceptor of claim 9, further comprising one or more other carbon nanostructures, the carbon nanostructure and the one or more other carbon nanostructures forming a bundle of carbon nanostructures and the light-responsive layer coating at least a portion of the bundle of carbon nanostructures.

24. The implantable photoreceptor of claim 23, wherein the light-responsive layer coats at least a portion of each carbon nanostructure in the bundle of carbon nanostructures.

25. The implantable photoreceptor of claim 23, wherein the bundle has a tapered end so as to enhance an electric field produced therefrom.

26. The implantable photoreceptor of claim 9, further comprising an insulating layer disposed on top of the light-responsive layer.

27. The implantable photoreceptor of claim 26, wherein the light-responsive layer is effective to generate, in response to light incident thereon, an electric charge in a portion of the photoreceptor, the electric charge producing an electric field external to the photoreceptor suitable to induce an action potential in at least one neuron adjacent the insulating layer.

28. The implantable photoreceptor of claim 9, wherein the light-responsive layer is operable to generate, an electric charge in a portion of the photoreceptor, the electric charge producing an electric field external to the photoreceptor suitable to induce an action potential in at least one neuron located at least about 50 nm from the implantable photoreceptor.

29. The implantable photoreceptor of claim 9, further comprising an insulating layer disposed on at least a portion of the surface of the carbon nanostructure that is not coated with the light-responsive layer.

30. The implantable photoreceptor of claim 9, wherein the carbon nanostructure has a length of about 2 to 50 microns and a width of about 500 to about 2000 nm.

31. The implantable photoreceptor of claim 9, wherein the light-responsive layer has a thickness of about 250 to about 2000 nm.

32. The implantable photoreceptor of claim 9, further comprising a wavelength-selective transparent layer disposed over the light-responsive layer.

33. A retinal implant, comprising

a plurality of photoreceptors disposed on a substrate, at least one of the photoreceptors including:

a carbon nanostructure;

a light-responsive layer coating at least a portion of a surface of the carbon nanostructure;

wherein the light-responsive layer is effective to generate, in response to light incident thereon, an electric field external to the photoreceptor suitable to induce an action potential in at least one neuron.

34. The retinal implant of claim 33, wherein the plurality of photoreceptors are disposed on the substrate with a density in a range of about 10³ to about 10⁹ photoreceptors per square millimeter.

35. The retinal implant of claim 33, wherein the plurality of photoreceptors are disposed on the substrate with a density in a range of about 1,000 to about 1,000,000 photoreceptors per square millimeter.

36. The retinal implant of claim 33, wherein the substrate is disk-shaped.

37. The retinal implant of claim 33, wherein the substrate is annular.

38. The retinal implant of claim 33, wherein the at least one photoreceptor further includes one or more other carbon nanostructures, the carbon nanostructure and the one or more other carbon nanostructures forming a bundle of carbon nanostructures and the light-responsive layer coating at least a portion of the bundle of carbon nanostructures.

39-86. -86. (canceled)