Disclosure of Invention
In view of the above, the invention provides a novel nerve stimulation array system which is provided with photoelectric conversion materials and metal electrode layers which are arrayed, has a simple structure and low manufacturing cost, can realize light response nerve electrical stimulation with spatial resolution without integrating a complex signal acquisition module, a wireless signal transmission and reception module and an integrated chip control module, and can be used for different nerve stimulation fields such as visual stimulation, cerebral cortex stimulation and the like.
Specifically, a first aspect of an embodiment of the present invention provides a neural stimulation array system, including: the photoelectric sensor comprises a flexible substrate, a photoelectric response layer and an electrode layer, wherein the photoelectric response layer is embedded into the flexible substrate and is formed by arranging photoelectric conversion materials in an array mode, and the electrode layer is located on the photoelectric response layer.
In the present invention, the electrode of the electrode layer is located on the surface of the photoelectric conversion material of the photoelectric response layer. Obviously, the electrode layers are also arranged by an array of conductive materials.
Optionally, the thickness of the electrode layer is 50-300nm.
Optionally, the flexible substrate has a thickness of 5-500 μm.
Wherein the thickness of the photoelectric response layer is less than or equal to the thickness of the flexible substrate. Preferably, the thickness of the photo-responsive layer is equal to the thickness of the flexible substrate, for example 5-500 μm.
In one embodiment of the invention, the flexible substrate has an array of holes, and the photoelectric response layer is filled in the holes of the array of holes; the holes are blind holes or through holes. The depth direction of the holes is parallel to the thickness direction of the flexible substrate. When the hole of the flexible substrate is a through hole penetrating through the thickness direction of the flexible substrate, the thickness of the photoelectric response layer is equal to the thickness of the flexible substrate.
Further, the holes are circular, triangular, quadrilateral, polygonal or other irregular shapes. Accordingly, the cross section of the photoelectric conversion material of the photoelectric response layer is circular, round, triangular, quadrilateral, polygonal or other irregular shapes.
Preferably, the holes are circular and have a diameter of 100 μm-2mm.
In the invention, the flexible substrate is made of insulating material, so that the diffusion of photoelectrons can be effectively inhibited, and the nerve stimulation array system realizes electric stimulation with resolution. The flexible substrate material may be a flexible insulating polymer, the choice of which depends on the end use and the desired effect of the application. For example, to ensure that a film substrate that can effectively conform to a curved surface structure can be formed, it is desirable to ensure that the flexible substrate material has good film formability and good mechanical properties at high curvatures.
Optionally, the material of the flexible substrate includes one or more of polyimide, polydimethylsiloxane, polyethylene terephthalate, parylene and photoresist. The photoresist may be a positive photoresist or a negative photoresist, and may be, but not limited to, SU8 photoresist, AZ photoresist, etc.
The electrode layer is made of at least one material selected from platinum, gold, titanium, iridium, palladium, niobium, tantalum and alloys thereof, titanium nitride (TixNy), iridium oxide (IrOx), indium Tin Oxide (ITO), aluminum doped zinc oxide (AZO), fluorine doped tin dioxide (FTO) and phosphorus doped tin dioxide (PTO), but not limited thereto.
In the invention, the photoelectric response layer has better photoelectric conversion efficiency and biocompatibility. Preferably, the photoelectric conversion material constituting the photoelectric response layer may be selected from at least one of the following substances having different photoelectric response mechanisms: photovoltaic material, photo-deformable material composite piezoelectric material and up-conversion material composite photovoltaic material.
Wherein the photovoltaic material can absorb photon energy in the visible region (400-800 nm) and thereby directly generate photoelectrons. The photoinduced deformation material composite piezoelectric material is firstly dependent on the photoinduced deformation material to generate deformation under the excitation of light rays in the visible light wave band (400-800 nm), so that the deformation material composite piezoelectric material is conducted to the piezoelectric material to generate a piezoelectric signal. The up-conversion material composite photovoltaic material is dependent on the up-conversion material absorbing photon energy in the near infrared region (780-2526 nm) and emitting photons with wavelengths in the visible region (400-800 nm), and thereby exciting the photovoltaic material in the response band to generate photoelectrons in the visible region. When the photoelectric conversion material is an up-conversion material composite photovoltaic material, the photoelectric response layer of the obtained nerve stimulation system can respond to light rays in a near infrared region (808-2500 nm) beyond a visible light region, so that the super-vision light ray perception capability is obtained.
Wherein the photovoltaic material is at least one of the following substances: monocrystalline silicon solar cell materials, thin film solar cell materials typified by amorphous silicon, copper indium gallium selenide thin films, and cadmium telluride thin films, dye sensitized solar cell materials based on titanium dioxide and a compound thereof, perovskite solar cell materials based on perovskite type organic metal halides, and organic photovoltaic materials of polyacetylenes, polythiophenes, polyanilines, polypyrroles, and derivatives and copolymers thereof. Examples of the perovskite-type organometal halide include lead carbamate, lead bromide, and lead chloride.
The composite piezoelectric material of the photo-deformable material is any one combination of the following photo-deformable material and piezoelectric material, wherein the photo-deformable material is at least one of the following materials: photoisomerization material represented by azobenzene and its derivative, spiropyran and its derivative; ferroelectric inorganic photodeformation materials represented by lead titanate, barium titanate, potassium niobate, lithium tantalate, bismuth layered perovskite structure ferroelectrics, tungsten bronze ferroelectrics, bismuth ferrite, monopotassium phosphate, triglycidyl ammonium sulfate, rochlote, and perovskite type organic metal halide ferroelectrics; non-ferroelectric inorganic photoinduced deformation materials represented by strontium ruthenate, silicon, cadmium sulfide and gallium arsenide; wherein the piezoelectric material is at least one of the following materials: piezoelectric crystals represented by quartz crystals, lithium gallate, lithium germanate, titanium germanate, and lithium tantalate; piezoelectric ceramics represented by barium titanate, lead zirconate titanate, lead metaniobate, lead barium lithium niobate; piezoelectric polymers represented by polyvinylidene fluoride ferroelectric polymers, odd nylon, polyacrylonitrile, vinylidene dicyano and copolymers thereof, polyurea, polyphenyl cyanoether, polyvinyl chloride, polyvinyl acetate, polypropylene, polytetrafluoroethylene. Among them, as the polyvinylidene fluoride-based ferroelectric polymer, there may be mentioned poly (vinylidene fluoride-trifluoroethylene) [ P (VDF-TrFE) copolymer ], poly (vinylidene fluoride-chlorotrifluoroethylene) [ P (VDF-CFE) copolymer ], poly (vinylidene fluoride-chlorotrifluoroethylene) [ P (VDF-CTFE) copolymer ], poly (vinylidene fluoride-hexafluoropropylene) [ P (VDF-HFP) copolymer ], poly (vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene) [ P (VDF-TrFE-CFE) terpolymer ], poly (vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene) [ P (VDF-TrFE-CTFE) terpolymer ] and poly (vinylidene fluoride-trifluoroethylene-hexafluoropropylene) [ P (VDF-TrFE-HFP) terpolymer ].
The up-conversion material composite photoelectric material is a composite material formed by up-conversion nanometer and at least one of the following materials: organic photovoltaic materials of polyacetylene, polythiophene, polyaniline, polypyrrole, derivatives and copolymers thereof. The up-conversion nanoparticle comprises a main body material, a sensitizer and an activator, wherein the main body material is NaYF4 or NaGdF4, the sensitizer is Yb, and the activator is Er, tm or Ho. Specifically, the up-conversion fluorescent material includes at least one of NaYF4:Yb3+,Er3+、YF3:Yb3+,Er3+、NaYF4:Yb3+,Tm3+、YF3:Yb3+,Tm3+、NaYF4:Yb3+,Ho3+ and YF3:Yb3+,Ho3+.
The nerve stimulating array system provided by the first aspect of the invention comprises a flexible substrate, a photoelectric response layer which is arranged on the flexible substrate and is formed by arrayed photoelectric conversion materials, and an arrayed electrode layer which is arranged on the photoelectric response layer, wherein the photoelectric response layer can directly generate photoelectrons with spatial resolution for stimulating nerves under optical stimulation without integrating complex signal acquisition modules, wireless signal transmission and reception modules, integrated chip control modules and other multifunctional modules, and the arrayed electrode layer can be used for realizing nerve electrical stimulation with spatial resolution. The nerve stimulation array system has the advantages of simple structure, low cost, good flexibility, high photoelectric conversion efficiency and good biocompatibility, can realize the photoelectric response electric stimulation of spatial resolution, and can be used in the field of different nerve electric stimulation of eyes, brains and the like.
In a second aspect, an embodiment of the present invention provides a method for preparing a neural stimulation array system, including the steps of:
Providing a hard substrate, and preparing a flexible substrate on the hard substrate;
preparing a hole array on the flexible substrate, filling a photoelectric conversion material into holes of the hole array, and forming a photoelectric response layer embedded in the flexible substrate;
Forming an electrode layer on the photoelectric conversion material of the photoelectric response layer;
Removing the hard substrate to obtain a nerve stimulation array system; the photoelectric response layer is formed by arranging photoelectric conversion materials in an array mode.
In one embodiment of the present invention, the preparation of the hole array on the flexible substrate specifically comprises: coating photoresist on the flexible substrate, and photoetching to form a patterned photoresist layer; forming a metal film on the patterned photoresist layer, removing the photoresist, and forming a patterned metal mask layer; and etching the flexible substrate to form the flexible substrate with the hole array. The patterned photoresist layer may be formed by exposing, developing, etc. the coated photoresist. Wherein, the material of the metal mask layer comprises aluminum, gold, silver and platinum. Preferably aluminum. Aluminum is used as a metal mask layer, and can be removed easily in the later stage.
Further, after forming the electrode layer on the photoelectric conversion material of the photoelectric response layer, it further includes: and removing the patterned metal mask layer.
Wherein the hard substrate is made of glass, metal, silicon or ceramic.
Wherein the flexible substrate may be formed of a flexible material by a coating method or a casting method.
Wherein the array of holes is formed by at least one of photolithography, plasma dry etching, and machining.
The filling mode of the photoelectric conversion material comprises one or more of physical embedding, coating, casting and in-situ growth.
The preparation method of the nerve stimulation array system provided by the second aspect of the invention is simple and convenient and easy to operate, and can be used for rapidly preparing the nerve stimulation array system with high integration level and simple structure, thereby greatly reducing the manufacturing cost of the current nerve stimulation system.
Advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the embodiments of the invention.
Detailed Description
For a better description of the objects, technical solutions and advantages of the present invention, the present invention will be further described with reference to the following specific examples.
Example 1
The nerve stimulation array system has a structure shown in fig. 1, and comprises a flexible substrate 10, a photoelectric response layer 20 inlaid in the flexible substrate 10, and an electrode layer 30 covered on the surface of the photoelectric response layer 20, wherein the photoelectric response layer 20 is formed by arranging photoelectric conversion materials in an array.
In this embodiment, as shown in fig. 2, the flexible substrate 10 has an array of holes formed of 9 circular through holes having a diameter of 2mm, and the photoelectric response layer 20 is filled in the holes of the array of holes; the thickness of the photoelectric response layer 20 is 200 μm, and the material is copper indium gallium selenide thin film solar cell material. The thickness of the flexible substrate 10 is 200 μm, and the material is Polydimethylsiloxane (PDMS); the electrode layer 30 has a thickness of 300nm and is made of Indium Tin Oxide (ITO).
The preparation method of the nerve stimulation array system comprises the following steps:
1) Surface treatment of hard substrate
And taking the monocrystalline silicon wafer as a hard substrate, and cleaning the surface of the monocrystalline silicon wafer to remove organic and inorganic impurities on the surface. The specific cleaning steps are as follows: sequentially ultrasonically cleaning in acetone, absolute ethyl alcohol and ultrapure water, drying by nitrogen, and then putting into a drying oven for drying; and then carrying out oxygen plasma treatment on the dried silicon wafer to make the surface hydrophilic.
2) Preparation of flexible substrates
Uniformly spin-coating a layer of pre-polymerized liquid of Polydimethylsiloxane (PDMS) on the surface of a monocrystalline silicon wafer by using a spin-coating instrument, and heating at 80 ℃ for 30min to solidify the pre-polymerized liquid to obtain a PDMS film with the thickness of 200 mu m, thus obtaining the flexible substrate. Spin-coating SU-8 photoresist with the thickness of 20 mu m on the surface of the PDMS film, and carrying out photoetching patterning on the photoresist to obtain a patterned photoresist layer; then forming an Al film with the thickness of 50nm on the surface of the substrate by magnetron sputtering, dissolving photoresist by using SU-8 developing solution, and forming a patterned metal mask layer of Al on the surface of the PDMS film; finally, carrying out plasma etching on the PDMS film which is not covered by the Al mask layer to form the PDMS flexible substrate with the thickness of 200 mu m and the array of 9 round holes with the diameter of 2 mm.
3) Preparation of a photoelectric response layer
Embedding a cylindrical copper indium gallium diselenide thin film solar cell material with the thickness of 200 mu m and the diameter of 2mm into the round hole of the PDMS flexible substrate; and filling PDMS prepolymer in the gap, and heating at 80 ℃ for 30min to solidify the PDMS prepolymer, so that the copper indium gallium selenide thin film solar cell material and the PDMS flexible substrate form an integrated structure.
4) Preparation of metal electrode layer
Under the masking action of the Al masking layer, depositing a layer of Indium Tin Oxide (ITO) electrode layer with the thickness of 300nm on the surface of the PDMS flexible substrate compounded with the photoelectric response layer by a magnetron sputtering coating method, wherein the metal electrode layer is positioned on the photoelectric conversion material of the photoelectric response layer. And then dissolving the Al mask layer serving as a mask by adopting a NaOH solution, and removing the monocrystalline silicon piece to finally obtain the nerve stimulating array system shown in figure 1.
The neural stimulation array system of the embodiment 1 of the invention has 9 electrodes, wherein the single electrode can stimulate the visual ganglion cells to show excitability under the excitation of a sunlight simulation illumination system (100 mW/cm2) with the emission wave band of visible light region (400-800 nm) and the output voltage of more than 5V and the output current of more than 10 mA.
Example 2
The nerve stimulation array system has a structure shown in fig. 1-2, and comprises a flexible substrate 10, a photoelectric response layer 20 inlaid in the flexible substrate 10, and an electrode layer 30 covered on the surface of the photoelectric response layer 20, wherein the photoelectric response layer 20 is formed by arranging photoelectric conversion materials in an array.
In the present embodiment, the flexible substrate 10 has an array of holes formed of 9 circular through holes having a diameter of 200 μm, and the photoelectric response layer 20 is filled in the holes of the array of holes; the thickness of the photoelectric response layer 20 is 5 μm, and the material is titanium dioxide nano-array with photovoltaic property. The thickness of the flexible substrate 10 is 5 μm, and the material is polyimide; the thickness of the electrode layer 30 was 50nm, and the material was Au.
The preparation method of the nerve stimulation array system comprises the following steps:
1) Surface treatment of hard substrate
And taking the polycrystalline silicon chip as a hard substrate, and cleaning the surface of the polycrystalline silicon chip to remove organic and inorganic impurities on the surface. The specific cleaning steps are as follows: sequentially ultrasonically cleaning in acetone, absolute ethyl alcohol and ultrapure water, drying by nitrogen, and then putting into a drying oven for drying; and then carrying out oxygen plasma treatment on the dried silicon wafer to make the surface hydrophilic.
2) Preparation of a flexible polymeric substrate layer
Uniformly spin-coating a polyimide acid solution on the surface of a polycrystalline silicon wafer by using a spin-coating instrument to form a wet film, heating at 100 ℃ for 3min, and then heating in a 300 ℃ oven for 0.5h to cyclize the polyimide acid to form polyimide, wherein the thickness of the polyimide is 5 mu m, thus obtaining the flexible substrate. Spin-coating SU-8 photoresist with the thickness of 20 mu m on the surface of the polyimide layer, and photoetching to pattern the photoresist to obtain a patterned photoresist layer; then forming an Al film with the thickness of 50nm on the surface of the polyimide layer by magnetron sputtering, dissolving photoresist, and forming a patterned metal mask layer of Al on the surface of the polyimide layer; finally, the polyimide uncovered by the Al mask layer is subjected to plasma etching to form a polyimide flexible substrate layer with the thickness of 5 mu m and the array of 9 round holes with the diameter of 200 mu m.
3) Preparation of a photoelectric response layer
Titanium dioxide nanowire arrays with the thickness of 5 mu m are selectively grown on the surface of a bare silicon wafer in a round hole of a polyimide flexible substrate layer through a hydrothermal method, and the thickness of the formed titanium dioxide nanowire array layer is controlled through controlling the addition amount and the reaction time of a reaction precursor (tetrabutyl titanate).
4) Preparation of metal electrode layer
Under the masking action of the Al masking layer, an Au metal electrode layer with the thickness of 50nm is deposited on the surface of the polyimide flexible substrate compounded with the photoelectric response layer by a magnetron sputtering coating method. And then dissolving the Al mask layer, and removing the monocrystalline silicon piece to finally obtain the nerve stimulation array system shown in figure 1.
The neural stimulation array system of embodiment 2 of the present invention has 9 electrodes, wherein a single electrode can stimulate the visual ganglion cells to exhibit excitability by generating an output voltage of more than 500mV and an output current of more than 100 μa under the excitation of a solar light simulation illumination system (100 mW/cm2) with an emission band of a visible light region (400-800 nm).
Example 3
The nerve stimulating array system has a structure shown in fig. 3, and comprises a flexible substrate 10, a photoelectric response layer 20 inlaid in the flexible substrate 10, and an electrode layer 30 covered on the surface of the photoelectric response layer 20, wherein the photoelectric response layer 20 is formed by arranging photoelectric conversion materials in an array.
In the present embodiment, the flexible substrate 10 has an array of holes formed of 9 square through holes having a side length of 500 μm, and the photoelectric response layer 20 is filled in the through holes of the array of holes but does not fill the through holes; the thickness of the photoelectric response layer 20 was 9.8. Mu.m, and the material was perovskite light absorbing substance such as lead-methyl iodide having photoelectric response characteristics. The thickness of the flexible substrate 10 is 10 mu m, and the material is parylene; the electrode layer 30 has a thickness of 300nm and is made of Au.
The preparation method of the nerve stimulation array system comprises the following steps:
1) Surface treatment of hard substrate
The glass sheet is taken as a hard substrate, and the surface of the glass sheet is cleaned to remove organic and inorganic impurities on the surface. The specific cleaning steps are as follows: sequentially ultrasonically cleaning in acetone, absolute ethyl alcohol and ultrapure water, drying by nitrogen, and then putting into a drying oven for drying; and then carrying out oxygen plasma treatment on the dried glass sheet to make the surface hydrophilic.
2) Preparation of a flexible polymeric substrate layer
And uniformly spin-coating a layer of parylene solution on the surface of the glass sheet by using a spin-coating instrument, and obtaining a parylene film with the thickness of 10 mu m by regulating the rotating speed, thus obtaining the flexible substrate. Spin-coating SU-8 photoresist with the thickness of 20 mu m on the surface of the parylene layer, and photoetching to pattern the photoresist to obtain a patterned photoresist layer; then forming an Al film with the thickness of 50nm on the surface of the photoresist through magnetron sputtering, and forming a patterned metal mask layer of Al on the surface of the parylene layer after dissolving the photoresist; finally, the parylene which is not covered by the Al mask layer is subjected to plasma etching to form the parylene flexible substrate with the thickness of 10 mu m and the square through hole array with the 9 side length of 500 mu m.
3) Preparation of a photoelectric response layer
Selectively growing a lead-methyl iodide layer with the thickness of 9.8 mu m on the surface of a bare glass sheet in a round hole of the parylene flexible substrate layer by a one-step solution method, and controlling the thickness of the formed lead-methyl iodide layer by controlling the addition amount of reaction precursors (lead iodide and methyl iodide).
4) Preparation of metal electrode layer
Under the masking action of the Al masking layer, depositing an Au metal electrode layer with the thickness of 300nm on the surface of the film compounded with the photoelectric response layer by a magnetron sputtering coating method. Then dissolving the Al mask layer serving as a mask plate, and removing the monocrystalline silicon piece to finally obtain the nerve stimulation array system shown in figure 1.
The single electrode of the nerve stimulation array system of the embodiment 3 of the invention can stimulate the visual ganglion cells to show excitability by generating output voltage of more than 5V and output current of more than 500 mu A under the excitation of the sunlight simulation illumination system (100 mW/cm2) with the emission wave band of visible light region (400-800 nm).
Example 4
A nerve stimulating array system capable of being simply integrated is shown in fig. 4, and comprises a flexible substrate 10, a photoelectric response layer 20 inlaid in the flexible substrate 10, and an electrode layer 30 covered on the surface of the photoelectric response layer 20, wherein the photoelectric response layer 20 is formed by arranging photoelectric conversion materials in an array.
In the present embodiment, the flexible substrate 10 has an array of holes formed of 9 circular through holes having a diameter of 500 μm, and the photoelectric response layer 20 is filled in the through holes of the array of holes, but does not fill the through holes; the thickness of the photoelectric response layer 20 is 190 μm, and the material of the photoelectric response layer is organic photovoltaic material poly (3-n-hexylthiophene). The thickness of the flexible substrate 10 is 200 mu m, and the material is polydimethylsiloxane; the thickness of the electrode layer 30 was 50nm, and the material was Pt.
The preparation method of the nerve stimulation array system comprises the following steps:
1) Surface treatment of hard substrate
And taking the monocrystalline silicon wafer as a hard substrate, and cleaning the surface of the monocrystalline silicon wafer to remove organic and inorganic impurities on the surface. The specific cleaning steps are as follows: sequentially ultrasonically cleaning in acetone, absolute ethyl alcohol and ultrapure water, drying by nitrogen, and then putting into a drying oven for drying; and then carrying out oxygen plasma treatment on the dried silicon wafer to make the surface hydrophilic.
2) Preparation of flexible substrates
Uniformly spin-coating a layer of pre-polymerized liquid of Polydimethylsiloxane (PDMS) on the surface of a monocrystalline silicon wafer by using a spin-coating instrument, and heating at 80 ℃ for 30min to solidify the pre-polymerized liquid to obtain a PDMS film with the thickness of 200 mu m, thus obtaining the flexible substrate. Spin-coating SU-8 photoresist with the thickness of 20 mu m on the surface of the PDMS film, and carrying out photoetching patterning on the photoresist to obtain a patterned photoresist layer; then forming an Al film with the thickness of 50nm on the surface of the substrate by magnetron sputtering, dissolving photoresist, and forming a patterned metal mask layer of Al on the surface of the PDMS film; finally, plasma etching is carried out on the PDMS film which is not covered by the Al mask layer, so that the PDMS flexible substrate with the thickness of 200 mu m and the array of 9 round holes with the diameter of 500 mu m is formed.
3) Preparation of a photoelectric response layer
And forming poly (3-n-hexylthiophene) with the thickness of 190 mu m on the surface of the bare silicon wafer in the round hole of the PDMS flexible substrate by a casting film forming method, and controlling the thickness of the formed poly (3-n-hexylthiophene) layer by controlling the volume and the concentration of a poly (3-n-hexylthiophene) solution used for casting film forming.
4) Preparation of metal electrode layer
Under the masking action of the Al masking layer, depositing a layer of Pt metal electrode layer with the thickness of 50nm on the surface of the PDMS flexible substrate compounded with the photoelectric response layer by a magnetron sputtering coating method, wherein the metal electrode layer is positioned on the photoelectric conversion material of the photoelectric response layer. And then removing the Al mask layer serving as a mask plate, and removing the monocrystalline silicon piece to finally obtain the nerve stimulation array system shown in figure 1.
The neural stimulation array system of this example 4 has 9 electrodes, wherein a single electrode can stimulate the visual ganglion cells to exhibit excitability by generating an output voltage of more than 200mV and an output current of more than 100 μa under the excitation of a solar simulated illumination system (100 mW/cm2) with an emission band of the visible light region (400-800 nm).
Example 5
As shown in fig. 5, the neural stimulation array system includes a flexible substrate 10, a photoelectric response layer 20 embedded in the flexible substrate 10, and an electrode layer 30 covering the surface of the photoelectric response layer 20, wherein the photoelectric response layer 20 is formed by arranging photoelectric conversion materials in an array.
In this embodiment, the flexible substrate 10 has an array of 9 holes formed by circular blind holes having a diameter of 200 μm, and the photoelectric response layer 20 is filled in the blind holes of the array of holes; the thickness of the photoelectric response layer 20 is 18 μm, and the material is poly (vinylidene fluoride-trifluoroethylene) having a piezoelectric effect compounded with azobenzene derivative having a photo-deformation characteristic. The thickness of the flexible substrate 10 is 20 μm, and the flexible substrate is made of polyethylene terephthalate (PET); the thickness of the electrode layer 30 was 50nm, and the material was Pt.
The preparation method of the nerve stimulation array system comprises the following steps:
1) Surface treatment of hard substrate
And taking the monocrystalline silicon wafer as a hard substrate, and cleaning the surface of the monocrystalline silicon wafer to remove organic and inorganic impurities on the surface. The specific cleaning steps are as follows: sequentially ultrasonically cleaning in acetone, absolute ethyl alcohol and ultrapure water, drying by nitrogen, and then putting into a drying oven for drying; and then carrying out oxygen plasma treatment on the dried silicon wafer to make the surface hydrophilic.
2) Preparation of flexible substrates
And uniformly spin-coating PET on the surface of the monocrystalline silicon piece by using a spin-coating instrument, and obtaining the PET film with the thickness of 20 mu m by regulating the rotating speed, thus obtaining the flexible substrate. Spin-coating SU-8 photoresist with the thickness of 20 mu m on the surface of the PET layer, and photoetching to pattern the photoresist to obtain a patterned photoresist layer; then forming an Al film with the thickness of 50nm on the surface of the substrate by magnetron sputtering, dissolving photoresist, and forming a patterned metal mask layer of Al on the surface of the PDMS film; finally, the PDMS film which is not covered by the Al mask layer is subjected to plasma etching to form the PET flexible substrate with the thickness of 18 mu m and the hole array of 9 round blind holes with the diameter of 200 mu m.
3) Preparation of a photoelectric response layer
And (3) dripping a precursor solution containing vinylidene fluoride-trifluoroethylene copolymer with the total mass concentration of 10mg/mL and the mass ratio of 4:1 and 4- (10-bromodecyloxy) -4' -octoxyazobenzene into the arrayed round holes of the PET flexible substrate, thoroughly drying at room temperature, and finally obtaining the photoelectric response layer (with the thickness of 18 mu m) with the thickness slightly smaller than that of the flexible polymer substrate layer by controlling the dripping times.
4) Preparation of metal electrode layer
And depositing a Pt metal electrode layer with the thickness of 50nm on the surface of the film compounded with the photoelectric response layer by a magnetron sputtering coating method, wherein the metal electrode layer is positioned on the photoelectric conversion material of the photoelectric response layer. The Al mask layer as a mask was then dissolved, resulting in a neural stimulation array system as shown in fig. 1.
The neurostimulation array system of this example 5 has 9 electrodes, and a single electrode can stimulate the ganglion cells to exhibit excitability by generating an output voltage of greater than 20mV and an output current of greater than 100 μA under excitation by visible light (100 mW/cm2) at wavelengths of 405, 532, and 650nm, respectively.
Example 6
The nerve stimulation array system comprises a flexible substrate 10, a photoelectric response layer 20 inlaid in the flexible substrate 10, and an electrode layer 30 covered on the surface of the photoelectric response layer 20, wherein the photoelectric response layer 20 is formed by arranging photoelectric conversion materials in an array.
In the present embodiment, the flexible substrate 10 has an array of holes formed of 9 circular through holes having a diameter of 200 μm, and the photoelectric response layer 20 is filled in the holes of the array of holes; the thickness of the photoelectric response layer 20 is 20 μm, and the material is poly (vinylidene fluoride-trifluoroethylene) having a piezoelectric effect by compounding strontium ruthenate having a photo-deformation characteristic. The thickness of the flexible substrate 10 is 20 μm, and the flexible substrate is made of polyethylene terephthalate (PET); the thickness of the electrode layer 30 was 50nm, and the material was Pt.
The preparation method of the nerve stimulation array system is similar to that of example 5, except that: in the step 3), a precursor solution containing 10mg/mL of vinylidene fluoride-trifluoroethylene copolymer and 0.1mg/mL of strontium ruthenate nano particles is dripped into an array round hole of a PET flexible substrate, and the precursor solution is thoroughly dried at room temperature, and the dripping times are controlled, so that the photoelectric response layer with the thickness consistent with that of the flexible polymer substrate layer (20 mu m) is finally obtained.
The neural stimulation array system of example 6 produces an output voltage greater than 50mV and an output current greater than 200 μA under excitation by visible light (100 mW/cm2) at wavelengths of 532 and 650nm, respectively, and is capable of stimulating the visual ganglion cells to exhibit excitability.
Example 7
The nerve stimulation array system comprises a flexible substrate 10, a photoelectric response layer 20 inlaid in the flexible substrate 10, and an electrode layer 30 covered on the surface of the photoelectric response layer 20, wherein the photoelectric response layer 20 is formed by arranging photoelectric conversion materials in an array.
In the present embodiment, the flexible substrate 10 has an array of holes formed of 9 circular through holes having a diameter of 200 μm, and the photoelectric response layer 20 is filled in the holes of the array of holes; the thickness of the photoelectric response layer 20 is 20 μm, and the material of the photoelectric response layer is up-conversion nano-particles NaYF4:Yb3+,Er3+ compounded with an organic photovoltaic material poly (3-n-hexylthiophene). The thickness of the flexible substrate 10 is 20 μm, and the flexible substrate is made of polyethylene terephthalate (PET); the thickness of the electrode layer 30 was 50nm, and the material was Pt.
The preparation method of the nerve stimulation array system comprises the following steps:
1) Surface treatment of hard substrate
And taking the monocrystalline silicon wafer as a hard substrate, and cleaning the surface of the monocrystalline silicon wafer to remove organic and inorganic impurities on the surface. The specific cleaning steps are as follows: sequentially ultrasonically cleaning in acetone, absolute ethyl alcohol and ultrapure water, drying by nitrogen, and then putting into a drying oven for drying; and then carrying out oxygen plasma treatment on the dried silicon wafer to make the surface hydrophilic.
2) Preparation of flexible substrates
And uniformly spin-coating PET on the surface of the monocrystalline silicon piece by using a spin-coating instrument, and obtaining the PET film with the thickness of 20 mu m by regulating the rotating speed, thus obtaining the flexible substrate. Spin-coating SU-8 photoresist with the thickness of 20 mu m on the surface of the PET layer, and photoetching to pattern the photoresist to obtain a patterned photoresist layer; then forming an Al film with the thickness of 50nm on the surface of the substrate by magnetron sputtering, dissolving photoresist, and forming a patterned metal mask layer of Al on the surface of the PDMS film; finally, the PDMS film which is not covered by the Al mask layer is subjected to plasma etching to form the PET flexible substrate with the thickness of 20 mu m and the hole array of 9 round holes with the diameter of 200 mu m.
3) Preparation of a photoelectric response layer
Adding a poly (3-n-hexylthiophene) solution with up-conversion nano particles NaYF4:Yb3+,Er3+ (NaYF 4 as a main material, yb as a sensitizer and Er as an activator) with the mass concentration of 10mg/mL into an array round hole coated on the PET flexible substrate, thoroughly drying at room temperature, and finally obtaining the photoelectric response layer with the thickness consistent with the thickness of the flexible polymer substrate layer (20 mu m) by controlling the dripping times.
4) Preparation of metal electrode layer
And depositing a Pt metal electrode layer with the thickness of 50nm on the surface of the film compounded with the photoelectric response layer by a magnetron sputtering coating method, wherein the metal electrode layer is positioned on the photoelectric conversion material of the photoelectric response layer. The Al mask layer as a mask was then dissolved, resulting in a neural stimulation array system as shown in fig. 1.
The individual electrodes of the neural stimulation array system of example 7 produced an output voltage greater than 200mV and an output current greater than 100 μA under excitation of near infrared lamps (100 mW/cm2) with emission wavelengths of 808nm, 1200nm, and 2500nm, respectively, and were capable of stimulating the ganglion cells to exhibit excitability.
The above examples merely represent exemplary embodiments of the invention, which are described in more detail and are not to be construed as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.