Optically active material, optoelectronic neural electrode and method for producing same

Abstract

The application belongs to the technical field of biological electrodes, and particularly relates to a photoactive material, a photoelectric nerve electrode and a preparation method thereof. The photoactive material is a thin film material composed of a polymer electron donor and a small molecule electron acceptor. The preparation method of the thin film material comprises the following steps: step 1, preparing a mixture thin film of the polymer electron donor and the small molecule electron acceptor; and step 2, exposing the mixture thin film to laser for treatment. The application further provides a photoelectric nerve electrode made of the photoactive material. The photoelectric conversion efficiency of the photoactive material is higher, and the photoelectric nerve electrode made of the photoactive material has better photoelectric performance, and has a wide application prospect in the treatment and research of brain neuron related diseases.

Description

Technical Field

[0001] This invention belongs to the field of bioelectrode technology, specifically relating to a photoactive material, a photoelectric nerve electrode, and its preparation method. Background Technology

[0002] With the development of neuroscience, brain science, and novel bioelectronics, the monitoring, stimulation, and modulation of neurological diseases and functions mediated by implantable neural electrodes are becoming increasingly important. Novel neural electrodes and neurostimulation technologies for the modulation of neurological diseases or functions are considered important directions for future neuroscience development and clinical applications. Conventional electrical stimulation requires brain surgery to implant electrodes, supplemented by complex circuitry and power connections, which greatly restricts patients' normal activities and increases the potential risks of neuromodulation. Novel photoelectric neural electrodes excited by remote light stimulation promise to solve this problem through non-invasive, distal stimulation.

[0003] Replacing traditional metals and semiconductors with flexible polymers as electrode materials is an important strategy for reducing immune rejection caused by mechanical mismatch at the neural interface. This is beneficial for improving the efficiency of electrical stimulation and recording at the neural interface by providing a biocompatible interface. The flexibility and photoelectric effect of opto-organic polymers offer hope for the development of novel flexible, wirelessly tunable opto-neural electrodes. Some studies have already attempted to fabricate various flexible photoelectrodes for neural stimulation (e.g., CN202010460927.9 A flexible neural photoelectrode for neural recording and stimulation and its fabrication method). However, achieving high photoelectric conversion efficiency and improving the biocompatibility and interfacial electron transport efficiency of the electrodes are key aspects of opto-electrode design.

[0004] This mainly depends on the photoelectric conversion effect of the photoactive materials constituting the electrode, the high light transmittance of the electrode substrate, the biocompatibility and tissue adhesion of the electrode-tissue interface, and the overall mechanical and biocompatibility of the electrode. Further research in this field is still needed to resolve these issues. Summary of the Invention

[0005] To address the problems of existing technologies, this invention provides a photoactive material, a photoelectric nerve electrode, and a method for preparing the same.

[0006] A photoactive material is a thin film material composed of a polymer electron donor and a small molecule electron acceptor. The preparation method of the thin film material includes the following steps:

[0007] Step 1: Prepare a mixed film of polymer electron donor and small molecule electron acceptor;

[0008] Step 2: Expose the mixture film to a laser for treatment, and the desired result is obtained.

[0009] Preferably, the polymer electron donor is selected from PCPDTBT, P3HT, and H2P. c At least one of them.

[0010] Preferably, the small molecule electron acceptor is selected from at least one of PCBM, fullerene, fullerene derivatives, PTCDI, and ITIC.

[0011] Preferably, the ratio of the polymer electron donor to the small molecule electron acceptor is 1:(1-1.5) by weight.

[0012] Preferably, step 1 specifically includes: preparing a mixed solution of a polymer electron donor and a small molecule electron acceptor, and preparing a mixed film of the mixed solution by spin coating;

[0013] The solvent of the mixed solution is selected from chlorobenzene; the spin coating process is specifically spin coating at 500-1000 rpm / s for 30-60s.

[0014] Preferably, in step 2, the laser is a femtosecond laser with a wavelength of 515-1030nm; the laser frequency is 80-1000kHz, the pulse energy is 0-100μJ, the pulse width is 100-800 femtoseconds, and the laser scanning speed is 10-100mm / s.

[0015] This invention also provides a method for preparing the above-mentioned photoactive material, comprising the following steps:

[0016] Step 1: Prepare a mixed film of polymer electron donor and small molecule electron acceptor;

[0017] Step 2: Expose the mixture film to a laser to obtain the final product.

[0018] The present invention also provides the use of the above-mentioned photoactive materials in the preparation of organic optoelectronic devices.

[0019] The present invention also provides a photoelectric nerve electrode, comprising: a substrate, an anode layer, a cathode interface layer, a cathode layer, and a photoactive layer made of the above-mentioned photoactive material.

[0020] Preferably, the substrate material is selected from polyethylene glycol diglycidyl ether modified silk fibroin membrane;

[0021] And / or, the material of the anode layer is selected from poly(3,4-ethylenedioxythiophene) doped with polystyrene sulfonate;

[0022] And / or, the material of the cathode layer is selected from poly(3,4-ethylenedioxythiophene) doped with polystyrene sulfonate;

[0023] And / or, the material of the cathode interface layer is selected from poly[9,9-bis(3'-(N,N-dimethyl)-N-ethylaminopropyl-2,7-fluoroene)-co-2,7-(9,9-dioctylfluoroene)] dibromide;

[0024] And / or, in the photoelectric nerve electrode, the order of the layers is as follows: substrate, anode layer, photoactive layer, cathode interface layer, cathode layer, or substrate, cathode layer, cathode interface layer, photoactive layer, anode layer;

[0025] And / or, the surface of the photoelectric nerve electrode is further provided with sodium alginate hydrogel.

[0026] This invention is the first to discover that laser annealing of thin film materials composed of polymer electron donors and small molecule electron acceptors using laser irradiation can effectively improve the photoelectric conversion efficiency of these materials. Furthermore, this invention optimizes the material composition and ratio of the polymer electron donor and small molecule electron acceptor, and further optimizes the parameters of the laser annealing process (laser wavelength, laser energy, and laser scanning speed), achieving the best possible improvement in photoelectric conversion efficiency. Through this discovery, this invention provides a photoactive material with higher photoelectric conversion efficiency. This photoactive material can be used in the fabrication of flexible photoelectrodes to enhance their photoelectric activity. Therefore, this invention has excellent application prospects.

[0027] Obviously, based on the above description of the present invention, and according to common technical knowledge and conventional methods in the field, various other modifications, substitutions, or alterations can be made without departing from the basic technical concept of the present invention.

[0028] The following detailed embodiments further illustrate the above-described content of the present invention. However, this should not be construed as limiting the scope of the present invention to the following examples. All technologies implemented based on the above-described content of the present invention fall within the scope of the present invention. Attached Figure Description

[0029] Figure 1The following are the characterization results of the photoactive materials and photoelectric nerve electrodes in Experiments 1 and 2. In Example a, the structure of the photoelectric nerve electrode PENE (PN type) is shown: cross-linked silk fibroin-PEDOT: PSS as the substrate and anode layer, PCPDTBT: PC60BM as the photoactive layer, and PFN-Br / PEDOT: PSS as the cathode interface / cathode layer; in Example b, a schematic diagram of laser-assisted photoactive layer morphology modulation; in Example c, the atomic force microscope images and UV-Vis curves of the untreated, thermally annealed, and laser-annealed photoactive layers; in Example ef, the GIWAX diffraction rings and corresponding out-of-plane files of the untreated, thermally annealed, and laser-annealed groups; in Example g, a schematic diagram of photovoltage testing; in Example h, the photovoltage curves generated by untreated and laser-annealed materials at a light intensity of 2.5 mW / mm²; in Example i, the cyclic photocurrent response; and in Example j, the photovoltage curves of the PN and NP types of PENE.

[0030] Figure 2 The results of the in vitro photoelectric neuronal activity modulation experiment in Experiment Example 3 are shown below. a) is a schematic diagram (left) of photoelectric stimulation modulation of PC12 cell activity using patch-clamp technique, an optical image of PC12 cells cultured on PENE; b) shows the cell density cultured on glass substrates, PN, and NP PENEs, respectively; c) shows the resting membrane potentials (RMPs) recorded for PC12 cells cultured on PN, NP PENEs, and glass substrates, respectively; d) shows the changes in cell membrane potentials of PC12 cells after light stimulation of PN and NP PENEs, recorded by patch-clamp; e) shows the changes in depolarization and hyperpolarization membrane potentials recorded by patch-clamp; f) shows the statistical analysis of depolarization and hyperpolarization membrane potentials under different light intensities; g) shows the fluorescence images of Fluo-4AM (top) / AMPA (bottom) dyes in PC12 cells over time after light stimulation of PN and NP PENEs, respectively; h) shows the Ca2+ levels of PC12 cells after light stimulation of PN and NP PENEs. 2+ Fluorescence intensity change (ΔF / F0), control group is cells stimulated only by light without PENE; i is a schematic diagram of the principle of cell depolarization and hyperpolarization by PN type and NP type PENE under light.

[0031] Figure 3The following are the results of the in vivo photoelectric neural activity modulation experiment in Example 4. In this experiment, a) is a schematic diagram of PENE-mediated photoelectric stimulation of the rat cerebral cortex; b) is a schematic diagram showing different photoelectric responses at the neural interface achieved by changing the structure of PENE (PN type and NP type); c) is the principle of PN-type PENE as a photoelectric neural interface and its interaction with changes in nerve cell membrane potential; d) is the local field potential (LFP) of the rat cerebral cortex and its corresponding time spectrum recorded by photoelectric stimulation based on PN-type PENE; and e) is the interaction of NP-type PENE as a photoelectric neural interface and its interaction with nerve cell membrane potential. The principle of change; f represents the local field potential (LFP) and corresponding time spectrum of the rat cerebral cortex recorded by photoelectric stimulation based on NP-type PENE; g represents the amplitude of the rat cerebral cortex field potential statistically based on PN-type and NP-type PENE photoelectric stimulation; h represents the corresponding power spectral density (PSD) value obtained from 3d and 3f; i represents the corresponding power spectral density values ​​of the control group (physiological saline), NP-type photoelectric stimulation (PES), and ES in the range of 10-30Hz; the inset shows the rat cerebral cortex field potential and time spectrum after conventional electrical stimulation (ES). Detailed Implementation

[0032] In the following examples and experimental cases, reagents and raw materials not specifically described are all commercially available products.

[0033] Example 1 Photoactive Materials

[0034] This embodiment provides a photoactive material, the preparation method of which is as follows:

[0035] Step 1, the polymer electron donor (poly[2,6-(4,4-bis(2-ethylhexyl)-4H-cyclopentadi[b;]thiophene)-substituted-benzo[d;t]benzothiazole], PCPDTBT, Sigma-Aldrich, USA) and the small molecule electron acceptor ([6,6]-phenyl-C61-butyrate, PC 60 The mixture film was prepared using BM (Sigma-Aldrich, USA). The specific steps are as follows:

[0036] 20mg PCPDTBT and 20mg PC 60 BM was dissolved in 2 mL of anhydrous chlorobenzene and mechanically stirred overnight at 70°C to obtain a homogeneous organic optoelectronic semiconductor mixed solution. The mixed solution was spin-coated at speed I: 500 rpm / s for 10 s, and then at speed II: 1000 rpm for 30 s.

[0037] Step 2: Expose the mixture film to laser light for treatment (laser annealing), and the desired result is obtained. The specific steps are as follows:

[0038] Laser annealing was performed using an ultrafast Ti:sapphire femtosecond laser with a wavelength of 515 nm to induce the reconstruction of photoactive molecules in the mixture film. The laser energy and scanning speed were precisely controlled by a computer program, with the laser energy ranging from 0-100 μJ and the laser scanning speed from 10-100 mm / s. In this embodiment, the preferred parameters were a laser energy of 50 μJ and a laser scanning speed of 10 mm / s.

[0039] The photoactive material prepared in this embodiment is composed of a PCPDTBT:PC60BM conjugated polymer mixture. PCPDTBT:PC60BM is a typical organic optoelectronic semiconductor (OPS) pair, in which PCPDTBT acts as an electron donor, and its HOMO and LUMO levels are precisely between those of the acceptor PC60BM. This arrangement facilitates energy level cascading, thereby enabling convenient transfer of charge carriers. Finally, another layer of PEDOT:PSS is coated as an anode conductive layer to conduct hole transport. Because PEDOT:PSS can conduct both electrons and holes simultaneously, it has a particularly wide range of applications and is suitable for playing multiple roles such as cathode or anode in organic optoelectronic devices.

[0040] In the photoactive material prepared in this embodiment, the high energy density of the laser induces the formation of photoexcited plasmas between PCPDTBT and PC60CBM molecules. Due to the π-π interactions between PCPDTBT molecules, PCPDTBT further aggregates to form PCPDTBT-rich domains, and PC60CBM does the same. At the microscale, the separation of PCPDTBT and PC60CBM-rich domains provides a basis for phase separation. After the laser scanning, the PCPDTBT and P60CBM molecules are rapidly cooled to room temperature. Due to the different crystallization temperatures, the phase distributions of PCPDTBT and P60CBM will be fixed in different states. Furthermore, the high energy of the laser can modulate the molecular interactions between PCPDTBT and P60CBM, thereby forming a more ordered molecular stack during rapid cooling and crystallization. In addition, compared with thermal annealing, the rapid crystallization time will greatly avoid the microstructural defects that may be caused by prolonged thermal annealing. Therefore, the recrystallization and phase separation of the photoactive layer will improve the charge transfer at the interface between PCPDTBT and P60CBM molecules.

[0041] Example 2: Photoelectric neural electrodes for neural modulation

[0042] This embodiment provides a PN-type photoelectric nerve electrode, comprising, in sequence: a substrate, an anode layer, a photoactive layer, a cathode interface layer, and a cathode layer.

[0043] Its preparation method includes the following steps:

[0044] Step 1, Prepare the substrate:

[0045] Cross-linked silk fibroin films were prepared by casting. 200 mg of lyophilized fibroin raw material (silk sourced from the Zhejiang Academy of Agricultural Sciences; extraction method: silk fibers were completely immersed in 0.02 M Na2CO3 aqueous solution at a bath ratio of 1:200, the mixed solution was boiled and maintained for 30 min, then washed with deionized water, repeated three times to obtain degummed silk; after the degummed silk was naturally dried, it was dissolved in 9.3 M LiBr at 60 °C, dialyzed in a dialysis bag for 72 h to remove bromide and lithium ions; finally, the dialyzed fibroin aqueous solution was lyophilized to obtain lyophilized fibroin raw material) was dissolved in 5 mL of deionized water to prepare a 4 w / t% fibroin aqueous solution, which was added to a 50 mL single-necked flask, and then polyethylene glycol diglycidyl ether (PEGDE) was added to make the PEGDE concentration 20 wt%, 30 wt%, or 40 wt% (the samples used in the following experimental data are the samples prepared in the experimental group with a PEGDE concentration of 30 wt%), and reacted at 60 °C for 1 h. Finally, 1 mL of the reaction solution was pressed into a square weighing boat with a side length of 1.5 × 1.5 cm and placed on a horizontal platform. The silk fibroin was allowed to air dry naturally to form a film, thus obtaining a cross-linked silk fibroin basement membrane (named SF).

[0046] Step 2, Prepare the anode layer:

[0047] A 1.5 × 1.5 cm glass cover slip was used as the substrate to facilitate the support and spin-coating of the cross-linked silk fibroin substrate (SF). A 100 mg / mL PEDDOT:PSS solution (pH 1000, Heraeus, Germany) was filtered (1 μm, PTFE filter) and then spin-coated at two speeds: I: 500 rpm for 10 s and II: 8000 rpm for 30 s, with a volume of 50 μL. The film was then annealed at 110 °C for 20 min. To improve the conductivity of PEDOT:PSS, DMSO was used as the solvent to wash away the PSS in the resulting film, followed by annealing at 110 °C for 20 min to obtain a transparent SF-PEDOT:PSS conductive film.

[0048] Step 3, Prepare the photoactive layer:

[0049] Photoactive materials were prepared on the surface of SF-PEDOT:PSS conductive films according to the method in Example 1.

[0050] Step 4, Prepare the cathode interface layer:

[0051] Poly[9,9-bis(3'-(N,N-dimethyl)-N-ethylaminopropyl-2,7-fluoroene)-co-2,7-(9,9-dioctylfluoroene)] dibromide (PFN-Br, Sigma-Aldrich, USA) was dissolved in methanol to prepare a 5 mg mL solution. -1 The PFN-Br methanol solution was spin-coated onto the photoactive layer surface at rotation speeds of 500 rpm for 10 seconds (I) and 3000 rpm for 30 seconds (II), with a volume of 100 μL. Finally, the solution was annealed at 110°C for 20 min to obtain the completed photoelectric neural electrode (P-SPE).

[0052] Step 5, Prepare the cathode layer:

[0053] The PEDOT:PSS layer was prepared using the same method as in step two and served as the cathode layer.

[0054] Step 6, Sodium alginate hydrogel modification:

[0055] A dissolved sodium alginate solution (10 mg / mL) was spin-coated onto the electrode surface at 1000 rpm (200 μL). Then, a 0.5 wt.% CaCl2 solution (50 μL) was added dropwise at 1000 rpm to induce rapid cross-linking. This yielded a sodium alginate hydrogel-modified silk fibroin photoelectric nerve electrode (PENE).

[0056] Example 3: Photoelectric neural electrodes for neural modulation

[0057] This embodiment provides an NP-type photoelectric nerve electrode, comprising, in sequence: a substrate, a cathode layer, a cathode interface layer, a photoactive layer, and an anode layer.

[0058] The composition and preparation method of each layer are the same as in Example 2. The difference is that the preparation order of the cathode layer, cathode interface layer and anode layer is adjusted according to the stacking method to prepare photoelectric nerve electrodes with different stacking methods.

[0059] Comparative Example 1: Photoactive materials prepared by heat annealing

[0060] The composition and preparation method of the photoactive material in this comparative example are the same as those in Example 1, except that the laser annealing in step 2 is not performed, but thermal annealing is used instead.

[0061] The specific steps of hot annealing are as follows: place the spin-coated photoelectric nerve electrode in a vacuum drying oven at 110℃ and heat it for 20 minutes.

[0062] Comparative Example 2: Photoactive material prepared without annealing.

[0063] The composition and preparation method of the photoactive material in this comparative example are the same as those in Example 1, except that the laser annealing in step 2 is not performed.

[0064] Comparative Example 3: Photoelectric nerve electrodes prepared by thermal annealing

[0065] The composition and preparation method of the photoelectric nerve electrode provided in this comparative example are the same as those in Example 2, except that the photoactive layer is prepared according to the method of Comparative Example 1 (i.e., instead of laser annealing in step 2, thermal annealing is used).

[0066] The technical solution of the present invention will be further illustrated by the following experiments.

[0067] Example 1: Characterization of Photoactive Materials

[0068] This experiment characterizes the laser-annealed photoactive material (PCPDTBT:PC60BM) prepared in Example 1, the thermally annealed photoactive material (PCPDTBT:PC60BM) prepared in Comparative Example 1, and the unannealed photoactive material (PCPDTBT:PC60BM) prepared in Comparative Example 2.

[0069] Using atomic force microscopy (AFM), Figure 1 c) Observation of the microstructure of the photoactive layer reveals that the unannealed PCPDTBT:PC60BM and the thermally annealed PCPDTBT:PC60BM exhibit typical miscibility of PCPDTBT and PC60BM chains. However, the laser-annealed PCPDTBT:PC60BM shows a larger interconnected region of PCPDTBT (purple) and PC60BM aggregate domains (yellow), indicating finer phase separation than thermal annealing. Clearly, laser annealing enhances the ordered stacking of PCPDTBT and PC60BM molecules and increases the degree of phase separation, which in turn promotes the separation of photoexcitons.

[0070] To further understand the effect of laser annealing on the microstructure of blends, we used UV-Vis spectroscopy and GIWAX to detect the molecular packing of photoactive molecules. Figure 1 d and Figure 1 e-1f). For example... Figure 1As shown in Figure d, the main absorption band of the PCPDTBT:PC60BM mixture without any annealing treatment is located in the 500-680 nm range. Conversely, the UV-Vis absorbance curve of the laser-annealed PCPDTBT:PC60BM mixture shows a red shift compared to the thermally annealed version, but without a significant shift. We attribute this adsorption shift to the inter-chain localization or intra-chain planarization excitation of PCPDTBT, resulting in a higher degree of ordering and increased π-conjugation length. The broad peak at 4A-1 mainly represents the out-of-plane alkyl chain stacking of PCPDTBT. Since the spherical fullerene structure of PC60BM covers the original PCPDTBT curve, the shapes of the three diffraction peaks are similar. Figure 1 f). However, the new diffraction peaks that appeared in the laser annealing group at q≈1.55A⁻¹ indicate that the π-π stacking of the PCPDTBT conjugated chains is more compact after laser annealing, which is beneficial for charge transport.

[0071] Example 2: Characterization of the photoelectric properties of the photoelectric nerve electrode (PENE)

[0072] I. Experimental Methods

[0073] This experiment characterized the photoelectric properties of laser-annealed PENE prepared in Example 2 and thermally annealed PENE prepared in Comparative Example 3. Furthermore, a comparative study verified that the PN-type PENE prepared in Example 2 and the NP-type PENE prepared in Example 3 possess different photoelectric properties.

[0074] In this experimental example, such as Figure 1 As shown in g, a glass pipette was used as the cathode to assemble PENE with an electrolyte (KCl, 0.1M) and a reference electrode (Ag / AgCl). The maximum photovoltage and photocurrent were then measured.

[0075] II. Experimental Results

[0076] from Figure 1 h shows that, with a 625nm optical pulse (10ms, 2.5mW / mm), 2 Under laser annealing, the maximum photovoltage of PENE reached 55 mV. Compared with the thermally annealed PENE prepared in Comparative Example 3, this value increased by approximately 30%, sufficient to induce a change in cell membrane potential. Similarly, we performed photocurrent experiments and plotted the photocurrent density curve (see...). Figure 1 i). Clearly, after five pulses of red light irradiation of PENE, a density of approximately 0.1 mA cm⁻¹ was observed. -2 The cyclic photocurrent response.

[0077] Subsequently, the photoelectric voltage of PN-type PENE and NP-type PENE were tested respectively, such as Figure 2 As shown in Figure j, PN-type PENE exhibits greater electron accumulation at the interface, leading to a relative increase in the photoelectric voltage recorded by the Ag / AgCl electrode. Conversely, NP-type PENE generates holes, resulting in a decrease in photoelectric voltage. These results indicate that laser processing of photoactive layer molecules can produce PENE with enhanced photoelectric response. The prepared PENE can be used as a photocathode (PN-type) and anode interface (NP-type), providing a possibility for further exploration of its neuromodulation potential.

[0078] The characterization experiments described above show that the photoactive material prepared by laser annealing in this invention has better photoelectric conversion efficiency and can improve the maximum photovoltage of the PENE it produces.

[0079] Experiment Example 3: In vitro photoelectric neural activity modulation

[0080] I. Experimental Methods

[0081] To investigate the effects of photoelectric neuromodulation on neuronal activity, we cultured PC12 pheochromocytoma cells (derived from rat adrenal medulla, in DMEM medium, 37°C, CO2 incubator) on either PN-type PENE prepared in Example 2 or NP-type PENE prepared in Example 3. We then assessed light-induced cell activity using whole-cell patch-clamp recordings. Figure 2 a) The PC12 cell line was chosen because it originates from pheochromocytoma of the adrenal medulla in rats and differentiates into a neuron-like phenotype, exhibiting morphological and biochemical characteristics similar to neurons.

[0082] Furthermore, this experimental example also investigated whether PENE could induce depolarization or hyperpolarization-related Ca2+ in larger cellular networks via light. 2+ Flow rate changes. Specifically, PC12 cells were seeded on PENE and treated with Ca... 2+ The cells were co-cultured with a fluorescent dye (Fluo-4AM, working solution diluted 1000 times). Then, laser confocal scanning microscopy (LCSM) was used to dynamically image changes in cell excitability under light stimulation.

[0083] II. Experimental Results

[0084] like Figure 2 As shown in b, there was almost no significant difference in cell density between PN and NP PENE cells cultured on glass substrates compared to PC12 cells cultured on glass substrates. Furthermore, after clamping the cell membrane with a pipette, the mean resting membrane potentials (RMPs) recorded in the PN and NP PENE groups in the dark ranged from -45 to -65 mV, comparable to the values ​​in the normal glass group. Subsequently, maintaining the potential at -65 mV, subthreshold induced changes in cell membrane potential were recorded under red light irradiation of different intensities. Figure 2 d). Clearly, the light pulse (0.5mW mm) -2 The PN type of PENE was acted upon, resulting in PC12 cell membrane depolarization of 7 ± 0.4 mV. When the pulse intensity was further increased to 1 and 2.5 mW mm... -2 At that time, the observed depolarization levels corresponded to 24 ± 0.65 and 25 ± 0.92 mV, respectively. Figure 2 d, top). The observed increase in membrane voltage can be attributed to the accumulation of photogenerated negative charges on the surface of PN-type PENE, leading to a relative increase in intracellular membrane voltage ( Figure 2 e, above figure). Conversely, when a similar optical pulse is applied to an NP-type PENE ( Figure 2 (d, lower part), membrane potentials were -4±0.4, -6±0.5, and -18±0.85 mV, respectively. This indicates that NP-type PENEs achieve hyperpolarization of the cell membrane. The photovoltage-induced accumulation of anions lowers the cell potential, which can also explain this result. Figure 2 e (see image below). Finally. Figure 2 f shows the opposite changes in PN and NP membrane potentials, respectively. This indicates that the designed PENE has the ability to modulate cell membrane potential. Furthermore, these millivolt-level photoelectric responses are sufficient to induce changes in cellular activity.

[0085] like Figure 2 As shown in g, the addition of Fluo-4AM to the PN-type PENE / PC12 solution immediately induces fluorescence emission upon the application of a light pulse to the PN-type PENE. With prolonged irradiation time, Ca2+ can be observed. 2+ The fluorescence intensity increased. Subsequently, the ability of PENE-mediated photoelectric stimulation to elicit repeatable responses in PC12 cells was investigated. Conversely, we used (±)-α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid hydrate (AMPA) to assess the inhibitory effect of light on NP-type PENE. Clearly, intracellular fluorescence intensity gradually decreased with prolonged illumination. Figure 2 g), this is due to Ca 2+ The efflux reduced the membrane potential, indicating that photoelectric stimulation of NP-type PENEs inhibited cell excitation. Furthermore, the corresponding fluorescence intensity curve dynamically decreased with increasing photostimulation load. Figure 2 h). Therefore, the selective manipulation of PC12 neural activity through different types of PENE photoelectric stimulation is consistent with previous whole-cell patch-clamp studies, suggesting that integrating PENE and photoelectric stimulation into a single radio-stimulation platform holds great promise for further epilepsy treatment.

[0086] Experiment Example 4: Regulation of Photoelectric Nerve Activity in Vivo

[0087] I. Experimental Methods

[0088] After confirming that photoelectric stimulation can generate sufficient voltage to induce cell polarization or depolarization through PN or NP type PENE, this experimental example further uses the PN type PENE prepared in Example 2 or the NP type PENE prepared in Example 3 as a wireless photoelectric platform to evaluate its ability to excite and inhibit neural activity in the cerebral cortex.

[0089] like Figure 3 As shown in Figure a, after removing the dura mater, we adhered two types of PENE to the somatosensory cortex of the mouse brain, using silver wires connected to skull screws as reference electrodes to perform photoelectric stimulation of the brain.

[0090] II. Experimental Results

[0091] Prior to light stimulation, we investigated the temperature changes of PENE under light irradiation using thermal infrared imaging. The results showed that the temperature change was minimal under different light energies, thus ruling out the possibility that light-induced temperature variations could cause tissue damage or neuronal responses.

[0092] For PN-type PENE, photostimulation generates negatively charged electrons at the cathode interface, leading to the accumulation of more positive ions within the neuronal cell. Figure 3 (b) and (3c), light stimulation causes an increase in intracellular potential. This mechanism is consistent with previous patch-clamp recordings of cellular depolarization. Therefore, when PN-type PENEs are irradiated with light pulses, the recorded electrophysiological data show increased neural excitability. Figure 3 As shown in Figure d, the upper panel displays a significant ridge wave with an amplitude of up to several hundred microvolts (μV), while the lower panel describes the enhanced discharge power from the low-frequency to the high-frequency region.

[0093] Conversely, NP-type PENEs generate positive charges at the interface. Figure 3 b (right), leading to a decrease in intracellular potential, blocking the transmission of positive charge signals from proximal to distal ends, thereby causing cell hyperpolarization ( Figure 3 e). Therefore, after applying photoload via NP-type PENE, the recorded electrophysiological data showed a significant inhibitory effect, manifested as a decrease in LFP curve amplitude (top figure) and a corresponding decrease in discharge power in the high-frequency region (bottom figure). Figure 3 f). Furthermore, compared to the control group (no light exposure), Figure 3 The g-3h dataset also shows quantitative data on LFP amplitude and discharge energy values, which are highly consistent with the LFP and time-frequency results. Furthermore, after applying anodic electrical stimulation (ES), such as... Figure 3As shown in i, the LFP curve and the corresponding time spectrum also show a similar decrease, and the PSD decreases significantly in every frequency band (10-30 Hz). These results undoubtedly indicate that NP-type PENE-mediated photoelectric stimulation has a comparable inhibitory effect to conventional ES.

[0094] Based on the above experimental records, combined with the previous patch-clamp and Ca... 2+ The results showed that photoelectric stimulation based on PN-type PENEs was more likely to induce increased excitability of neurons in the cerebral cortex. Conversely, photoelectric stimulation of NP-type PENEs inhibited neural activity. Therefore, the two types of PENEs provided by this invention can play different roles in various neuronal diseases. For example, since epileptic seizures involve highly synchronized firing of brain neurons and abnormal neural hyperexcitability, NP-type PENEs are well-suited for studying photoelectric inhibition of epileptic seizures.

[0095] As can be seen from the above embodiments and experimental examples, the present invention provides a photoactive material with higher photoelectric conversion efficiency. This photoactive material can be used to fabricate photoelectric neural electrodes with better photoelectric properties, showing broad application prospects in the treatment and research of neuronal diseases.

Claims

1. An optically active material, characterized by: It is a thin film material composed of a polymer electron donor selected from PCPDTBT and a small molecule electron acceptor selected from PCBM, the ratio of the polymer electron donor and the small molecule electron acceptor is 1:(1-1.5) by weight, and the preparation method of the thin film material comprises the following steps: 60 BM, the ratio of the polymer electron donor and the small molecule electron acceptor is 1:(1-1.5) by weight, and the preparation method of the thin film material comprises the following steps: Step 1, preparing a mixture film of the polymer electron donor and the small molecule electron acceptor; Step 2, exposing the mixture film to laser for laser annealing, thereby obtaining the photoactive material. The laser is a femtosecond laser with a wavelength of 515-1030 nm, a frequency of 80-1000 kHz, a pulse energy of 0-100 μJ, and a pulse width of 100-800 femtosecond; and the laser scanning speed is 10-100 mm / s.

2. The photoactive material according to claim 1, characterized in that: In step 1, the polymer electron donor and the small molecule electron acceptor are prepared into a mixed solution, and the mixed solution is prepared into a mixture film by spin coating. The solvent of the mixed solution is selected from chlorobenzene, and the spin coating process is specifically spin coating at 500-1000 rpm / s for 30-60 s.

3. The method of producing an optically active material according to claim 1 or 2, characterized by: The method comprises the following steps: Step 1, preparing a mixture film of the polymer electron donor and the small molecule electron acceptor; Step 2, exposing the mixture film to laser for laser annealing, thereby obtaining the photoactive material.

4. Use of the photoactive material of claim 1 or 2 in the preparation of an organic optoelectronic device.

5. An optoelectronic neural electrode, characterized by The method comprises: a substrate, an anode layer, a cathode interface layer, a cathode layer, and a photoactive layer prepared from the photoactive material of claim 1 or 2.

6. The optoelectronic neural electrode of claim 5, wherein: The material of the substrate is selected from polyethylene glycol diglycidyl ether modified silk fibroin film; and / or, the material of the anode layer is selected from polystyrene sulfonate doped poly(3,4-ethylenedioxythiophene); and / or, the material of the cathode layer is selected from polystyrene sulfonate doped poly(3,4-ethylenedioxythiophene); and / or, the material of the cathode interface layer is selected from poly[9,9-bis(3'-(N,N-dimethyl)-N-ethylaminopropyl-2,7-fluorene)-co-2,7-(9,9-dioctylfluorene)] dibromide; and / or, in the optoelectronic neural electrode, the layers are arranged in the following order: substrate, anode layer, photoactive layer, cathode interface layer, cathode layer, or substrate, cathode layer, cathode interface layer, photoactive layer, anode layer; and / or, the surface of the optoelectronic neural electrode is further provided with sodium alginate hydrogel.

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