An implantable multi-brain region regulation hydrogel optical fiber device and its preparation method

Abstract

The present invention discloses an implantable multi-brain region regulating hydrogel optical fiber device and a preparation method thereof, belonging to the technical field of advanced functional optical fiber material preparation. The present invention combines the hydrogel optical fiber manufacturing process with femtosecond laser micromachining technology to complete the preparation of a hydrogel optical fiber device with multi-brain region regulating function. Specifically, it is mainly realized by using the pulling method and femtosecond laser micromachining technology. The cladding is coated on the surface of the fiber core by the pulling method, and the hydrogel optical fiber is stretched to lose water by subsequent vertical suspension. Then, the femtosecond laser micromachining system and the STL graphic call function are used to perform groove etching to manufacture a double-groove hydrogel optical fiber device with different section angles, so that it has the function of realizing multi-brain region regulation.

Description

Technical Field

[0001] The present invention relates to the technical field of advanced functional optical fiber material preparation, and in particular to an implantable multi-brain region regulating hydrogel optical fiber device and a preparation method thereof. Background Art

[0002] Multi-brain region manipulation is a neuroscience technique that aims to understand and regulate brain function by manipulating the activity of different brain regions. This involves the use of various techniques to achieve precise control and manipulation of specific brain regions or neuronal groups. By modulating the interactions between multiple brain regions, more effective treatments for neurological diseases can be achieved. It can also promote neurological recovery and regulate damaged neural networks, helping to promote the recovery and remodeling of neural function. Modulating the interactions between multiple brain regions can also provide a deeper understanding of brain function.

[0003] Current methods for regulating multiple brain regions include neuromodulation, brain-computer interface (BCI), and optogenetics. Neuromodulation techniques, such as electrical stimulation, magnetic stimulation, and deep brain stimulation, regulate the activity of specific brain regions through external stimulation. Brain-computer interface (BCI) uses implanted electrodes or sensors to interact with the brain, enabling real-time monitoring and regulation of multiple brain regions. Optogenetics utilizes light-sensitive proteins to stimulate specific neurons, enabling precise control of neuronal activity.

[0004] There are certain limitations and uncertainties in the use of neuromodulation technology and brain-computer interface technology for multi-brain region control. For example, the effectiveness of neuromodulation technology may be affected by factors such as individual differences, electrode position and parameter settings, resulting in increased inaccuracy in multi-brain region control. Electrical brain-computer interface devices have only limited functional control power and cannot achieve fine control. The information transmission speed is slow and depends on the external environment. Under the influence of electromagnetic interference, their measurement performance will be reduced, greatly affecting the accuracy of signal detection. At the same time, the long-term stability and durability of implanted electrodes are also a problem, because implanted devices may be affected by the reaction of surrounding tissues and biological corrosion, resulting in electrode failure. The use of optogenetics can effectively circumvent the above disadvantages and control multi-brain regions without electromagnetic interference.

[0005] In the past, quartz optical fiber or polymer optical fiber was commonly used for optogenetic brain region regulation. However, due to the materials used, these three optical fibers have poor biocompatibility. Even if biological corrosion and electromagnetic interference can be eliminated, more glial cells will be produced when implanted in the brain, causing the body’s rejection reaction and potential immune response as well as foreign body reaction. When used, these three optical fibers can only be used to regulate the brain region to control a single brain region, and cannot achieve simultaneous regulation of multiple brain regions, which will result in incomplete and inaccurate analysis of brain region information. Therefore, an ideal optical waveguide device with excellent biocompatibility, high durability, and the ability to achieve multi-brain region regulation is needed to achieve long-term and effective multi-brain region neural regulation.

[0006] Hydrogel optical fiber is a new type of optical sensor with advantages such as high biocompatibility, high sensitivity, high stability, and adjustability, which make it suitable for application in optogenetics. With the development of materials science and process design, the preparation and performance of hydrogel materials have been continuously improved, providing a good foundation for the research of hydrogel optical fiber. By combining the characteristics of hydrogel with the advantages of optical fiber sensors, high-sensitivity detection of tiny objects, trace substances, and microenvironments can be achieved, thus playing an important role in medical diagnosis, internal environment monitoring and other fields. However, at this stage, there is still a lack of research on high-performance implantable hydrogel optical fiber devices for multi-brain region regulation. Summary of the Invention

[0007] The purpose of the present invention is to provide an implantable multi-brain region regulation hydrogel fiber device and a preparation method thereof, in order to solve the problems existing in the above-mentioned prior art. The present invention combines the hydrogel fiber manufacturing process and femtosecond laser micromachining technology to complete the preparation of a hydrogel fiber device with multi-brain region regulation function. Specifically, it is mainly achieved by using the pulling method and femtosecond laser micromachining technology. The cladding is coated on the surface of the fiber core by the pulling method, and the hydrogel fiber is stretched to lose water through subsequent vertical suspension. Then, the femtosecond laser micromachining system and the STL graphic call function are used to perform groove etching to manufacture double-groove hydrogel fiber devices with different section angles, so that it has the function of realizing multi-brain region regulation.

[0008] To achieve the above object, the present invention provides the following solutions:

[0009] One of the technical solutions of the present invention is a method for preparing an implantable multi-brain region regulating hydrogel optical fiber device, comprising the following steps:

[0010] S1. Mixing a core precursor solution and a photocuring agent solution to obtain a mixed solution; transferring the mixed solution to a mold, and performing a photocuring reaction under ultraviolet light irradiation to obtain a hydrogel core; rotating and pulling the hydrogel core in a cladding solution, and then soaking the hydrogel core in a calcium chloride solution after the rotation and pulling to form a cladding on the surface of the hydrogel core; then vertically hanging the hydrogel core coated with the cladding to air-dry, to obtain a hydrogel optical fiber (the hydrogel optical fiber consists of a core and a cladding, has a double-layer structure, and is a cylinder).

[0011] S2. Based on the two different light-sensitive proteins selected when using light-sensitive proteins to light-stimulate neurons in different brain regions or neurons in different regions of the same brain region, two beams of probe light with different wavelengths are selected to be injected into the implantable multi-brain region regulation hydrogel optical fiber device. The refractive index of the core of the hydrogel optical fiber to the two beams of probe light with different wavelengths is tested, denoted as n1 and n2. The tangent angle between the groove and the hydrogel optical fiber is calculated based on the refractive index, denoted as and Two beams of light with different wavelengths have two different refractive indices in the hydrogel fiber core, and two different cut angles can be calculated;

[0012] S3, calculated according to step S2 and Etching two grooves in the hydrogel optical fiber to obtain a double-groove hydrogel optical fiber; wherein the etching depth of the groove having a smaller tangential angle with the hydrogel optical fiber is 100±10 μm, and the etching depth of the groove having a larger tangential angle with the hydrogel optical fiber is 200±10 μm (setting the etching depth in this manner can better transmit the two beams of light and ensure the stability of the hydrogel optical fiber device);

[0013] S4. Connect the silicon chip to one end of the double-groove hydrogel optical fiber (i.e., bond the silicon chip to one end face of the cylinder) to suppress the emission from the end face of the optical fiber, thereby obtaining the implantable multi-brain region regulating hydrogel optical fiber device.

[0014] Furthermore, in step S1, the raw material composition of the core precursor solution is, by volume percentage, 35%-45% acrylamide, 0.5%-1% N,N'-methylenebisacrylamide, 1.5%-2% ammonium persulfate and the balance water; the raw material composition of the cladding solution is, by volume percentage, 1%-2% EDC (1-ethyl-(3-dimethylaminopropyl)carbodiimide), 1.2%-2.5% Sulfo-NHS (N-hydroxysulfosuccinimide), 20%-26% sodium alginate, 0.05%-0.08% TEMED (tetramethylethylenediamine) and the balance water; the raw material composition of the photocuring agent solution is, by volume percentage, 0.2%-0.35% Irgacure and the balance water.

[0015] Furthermore, the mass fraction of the calcium chloride solution is 10%; and the soaking treatment time is 2 minutes.

[0016] The acrylamide monomer compound in the core precursor solution is used to form a high molecular weight hydrogel polymer, N,N'-methylenebisacrylamide provides unsaturated bonds and multiple functional group cross-linking monomers to connect into a high molecular weight network, and ammonium persulfate makes the hydrogel more tensile. Irgacure in the photocuring agent solution is used to absorb photon energy to induce cross-linking of the monomer compound. EDC and Sulfo-NHS in the cladding solution form strong chemical bonds with the surface of the hydrogel core through chemical induction. After the chemical bond is formed, it is immersed in a 10% by mass calcium chloride solution for 2 minutes to promote sodium alginate and calcium ions to form a complete hydrogel optical fiber cladding.

[0017] Furthermore, in step S1, the power of the ultraviolet light irradiation is 107 mW / cm 2 , the wavelength of the ultraviolet light is 396nm.

[0018] Furthermore, in step S1, the mold is a polytetrafluoroethylene tube. After the curing reaction is completed, the operation of removing the tube and extracting the hydrogel core is also included. After removing the tube and extracting the hydrogel core, a length of the hydrogel core can be cut first, and after air-drying (air-dried at room temperature for 6 hours), it can be used to test the refractive index of two beams of detection light with different wavelengths in step 2, as the refractive index of the core of the hydrogel optical fiber to the two beams of detection light with different wavelengths, and the remaining part is then clad. It is also possible to use a mixed solution of the same composition (mixed by a core precursor solution and a photocuring agent solution) while preparing the hydrogel core, and use the same photocuring process to prepare a hydrogel sample separately and air-dry (air-dried at room temperature for 6 hours) for testing the refractive index of two beams of detection light with different wavelengths in step 2, as the refractive index of the core of the hydrogel optical fiber to the two beams of detection light with different wavelengths.

[0019] Furthermore, in step S1, the specific operation of the rotational pulling is: first immersing the hydrogel fiber core in the cladding solution for 10 seconds, and then repeatedly pulling it 30-35 times at a pulling speed of 1 cm / s.

[0020] Furthermore, the cladding solution is placed in a culture dish during rotational pulling. During the repeated pulling process, the hydrogel fiber core is rotated 360° clockwise around the culture dish in the cladding solution in the culture dish every three times, and the rotation angular velocity is controlled to be 180° / s. The entire rotational pulling process lasts for 2-3 minutes.

[0021] When the hydrogel fiber core is rotated and pulled in the cladding solution, it needs to be rotated and pulled multiple times and cannot be immersed for a long time. The entire pulling process needs to be continued to prevent uneven cladding.

[0022] Furthermore, in step S1, the specific operation of vertically hanging the clad hydrogel fiber core for air drying is as follows: fix one end of the clad hydrogel fiber core with a tool, hang it vertically in the air, let it stand for 20 minutes, then fix the other end of the clad hydrogel fiber core with a tool, let the tool fall freely, thereby stretching the hydrogel fiber, and continue to hang it vertically for 6 hours (at room temperature). During the operation before air drying, in order to prevent the hydrogel fiber from changing its shape, the surface of the hydrogel fiber should be kept away from any solid matter until it is air-dried.

[0023] Furthermore, the tool is a binder clip.

[0024] Furthermore, in step S2, different probe lights are selected based on the two different light-sensitive proteins selected when using light-sensitive proteins to photostimulate neurons in different brain regions or neurons in different regions of the same brain region (i.e., based on different experimental test requirements). When the light-sensitive protein used changes, the probe light needs to be reselected, and the hydrogel optical fiber device is re-prepared based on the selected probe light. For example, if the light-sensitive protein Channelrhodopsin-2 (ChR2) needs to be used to photostimulate specific neurons in a certain brain region, the maximum absorption wavelength is approximately 470 nm, and light with a wavelength of 470 nm is selected as the probe light; if the light-sensitive protein Halorhodopsin (NpHR) needs to be used to photostimulate specific neurons in a certain brain region, the maximum absorption wavelength is approximately 590 nm, and light with a wavelength of 590 nm is selected as the probe light; if the light-sensitive protein Cobalamin-binding Channelrhodopsin (CoChR) needs to be used to photostimulate specific neurons in a certain brain region, the maximum absorption wavelength is approximately 520 nm, and light with a wavelength of 520 nm is selected as the probe light. When it is necessary to simultaneously use ChR2 and NpHR to perform optical stimulation and regulation on neurons in different brain regions or neurons in different regions of the same brain region, two beams of light with wavelengths of 470nm and 590nm are selected as detection lights for irradiating the implantable multi-brain region regulation hydrogel fiber optic device. Based on these two beams of light, a hydrogel fiber optic device is prepared that simultaneously uses ChR2 and NpHR to perform optical stimulation and regulation on neurons in different brain regions or neurons in different regions of the same brain region.

[0025] Furthermore, the refractive index of the core of the test hydrogel optical fiber to the two probe lights of different wavelengths in step S2 is measured by an Abbe refractive index meter.

[0026] Furthermore, the tangent angle between the groove and the hydrogel optical fiber is calculated according to the formula calculate.

[0027] Furthermore, before etching the grooves, the appropriate length of the hydrogel optical fiber is selected and the appropriate distance between the two grooves is selected according to the size of the brain area of ​​the experimental animal and the distribution of the neurons to be regulated.

[0028] Furthermore, the etching is performed by a femtosecond laser micromachining system, and the etching wavelength is 1028 nm.

[0029] Furthermore, the etching parameters include: pulse energy of 0.2 mJ, pulse width of 120 fs, and repetition frequency of 1 kHz. The etching wavelength, pulse energy, pulse width, and repetition frequency in the two groove etching processes are the same.

[0030] The etching of the grooves is mainly carried out by a femtosecond laser micromachining system, and the STL graphic call function is used to control the size and shape of the grooves. During the femtosecond processing, it is necessary to adjust the optimization parameters to etch the grooves to prevent the hydrogel fiber from breaking or the grooves from being too rough. Specifically, the hydrogel fiber is first fixed with a fiber clamp, and then the hydrogel fiber is fixed to the glass slide with tape. The position of the hydrogel fiber is adjusted by a multi-axis angle-adjustable platform to improve the accuracy of femtosecond laser engraving. By comparing the effects of etching wavelength, pulse energy, pulse frequency and pulse width on groove engraving, the femtosecond laser is optimized and adjusted to determine the etching wavelength to be 1028nm, the pulse energy to be 0.2mJ, the pulse width to be 120fs, and the repetition frequency to be 1KHz.

[0031] Furthermore, the specific operation of connecting the silicon wafer to one end of the double-groove hydrogel optical fiber is to connect and solidify the silicon wafer and one end of the hydrogel optical fiber using the mixed solution described in step S1, and then clad the connection with the cladding solution described in step S1 after solidification. The purpose of this step is to suppress emission from the end face of the double-groove hydrogel optical fiber.

[0032] Furthermore, before connecting the silicon wafer to one end of the double-groove hydrogel optical fiber, a pretreatment process of the silicon wafer is also included. The specific operations of the pretreatment are: cleaning the silicon wafer with alcohol and acetone, cutting it with a cutting blade after drying, and cleaning it again with alcohol and drying it.

[0033] Furthermore, the size of the silicon wafer after cutting is the same as the end face size of the double-groove hydrogel optical fiber.

[0034] The second technical solution of the present invention: an implantable multi-brain region regulating hydrogel optical fiber device prepared by the above-mentioned preparation method.

[0035] Furthermore, the diameter (outer diameter) of the hydrogel optical fiber is 400±20 μm, wherein the core diameter is 350±10 μm, and the cladding thickness is 25±5 μm.

[0036] The third technical solution of the present invention: the application of the above-mentioned implantable multi-brain region control hydrogel optical fiber device as an optical brain-computer interface to prepare a multi-brain region control device.

[0037] Furthermore, the multi-brain region regulation is specifically the recording and closed-loop regulation of specific neurons in multiple brain regions.

[0038] Furthermore, the multi-brain region regulation specifically refers to regulating neurons in different brain regions (two brain regions) or neurons in (two) different regions in the same brain region through optogenetic technology, that is, using light-sensitive proteins to light stimulate specific neurons in different brain regions (two brain regions) or in (two) different regions in the same brain region, so as to achieve precise control of neuronal activity.

[0039] The implantable multi-brain region control hydrogel fiber optic device of the present invention can regulate specific neurons in multiple brain regions (two brain regions, or different regions of the same brain region) using a single fiber. Specifically, the optical parameters of the two grooves of the hydrogel fiber optic brain-computer interface device are first measured in vitro, including wavelength and light emission angle, to ensure that the two probe beams injected into the hydrogel fiber optic device can pass through the two grooves and illuminate different brain regions. The hydrogel fiber optic brain-computer interface device (i.e., the hydrogel fiber optic device of the present invention) is then implanted into the brain of a mouse, and optogenetic stimulation is performed on multiple brain regions with known functions. The effect of the regulation is evaluated by analyzing the mouse's behavioral performance. Taking the instinctive defense circuit as an example, three important brain regions in this circuit are all located on the same coronal section and close to the midline, and they can be regulated separately using a single fiber. Simultaneously activating specific neurons in these brain regions will trigger instinctive defensive behavior. Activating downstream neurons while inhibiting upstream neurons will also trigger instinctive defensive behavior. Activating upstream neurons while inhibiting downstream neurons will weaken or even suppress instinctive defensive behavior. By analyzing instinctive defensive behavior, the effects of activation and inhibition on individual brain regions can be inferred.

[0040] The present invention discloses the following technical effects:

[0041] The implantable multi-brain region regulation hydrogel fiber optic device prepared by the present invention has better biocompatibility than quartz fiber and polymer fiber: the hydrogel fiber is made of materials with good biocompatibility, and when implanted in the brain region, it can reduce the production of glial cells, reduce the body's rejection reaction, and reduce potential immune reactions and foreign body reactions, thereby achieving long-term signal recording.

[0042] The implantable multi-brain region regulating hydrogel fiber optic device prepared by the present invention has higher flexibility: hydrogel fiber is softer and easier to bend and fold than quartz fiber and polymer fiber, and is therefore more suitable for application scenarios that require high flexibility, such as in the bending and torsion environment of medical devices.

[0043] The implantable multi-brain region regulating hydrogel optical fiber device prepared by the present invention has high sensitivity, thereby facilitating the monitoring of weak signals and enhancing the performance of optical sensors.

[0044] The present invention realizes the integration of femtosecond micromachining technology and hydrogel optical fiber manufacturing process. By controlling the parameters of the processing system, double-groove hydrogel optical fiber with specific functions can be customized to meet the needs of practical applications, which has great practical value.

[0045] The implantable multi-brain region control hydrogel fiber optic device prepared by this invention can be used as an optical brain-computer interface device for neural regulation and monitoring of brain region information changes. The dual-groove design enables the fiber optic to monitor and analyze multiple information sources. This device offers simple operation and accurate results for neural regulation and brain region information monitoring, demonstrating its practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0047] Figure 1 Schematic diagram of the operation of rotating and pulling the optical fiber cladding in the present invention;

[0048] Figure 2 This is a schematic diagram of the operation of vertically hanging optical fibers for air drying in the present invention;

[0049] Figure 3 Schematic diagram of the double-groove etching process of the hydrogel optical fiber of the present invention, wherein 3-1 is a femtosecond laser, 3-2 is a HWP, 3-3 is a GP, 3-4 is a CM, 3-5 is a QWP, 3-6 is a reflector, 3-7 is a CCD, 3-8 is a computer, 3-9 is a dichroic mirror, 3-10 is a microscope lens, 3-11 is an air-dried hydrogel optical fiber, 3-12 is a 6-axis precision displacement stage, and 3-13 is a front view of the double-groove hydrogel optical fiber;

[0050] Figure 4Schematic diagram of the process of suppressing emission from the optical fiber end face in the present invention, wherein 4-1 is alcohol, 4-2 is acetone, 4-3 is a silicon wafer, 4-4 is a blade, 4-5 is a small silicon wafer that has been cut, 4-6 is a beaker filled with alcohol, 4-7 is a double-groove hydrogel optical fiber, 4-8 is a glass slide, 4-9 is a mixed solution, and 4-10 is a bonded hydrogel optical fiber device;

[0051] Figure 5 Schematic diagram of a double-groove hydrogel optical fiber obtained after double-groove etching in the present invention, wherein 5-1 is a hydrogel optical fiber with double-groove etching, 5-2 is groove 1, and 5-3 is groove 2;

[0052] Figure 6 Schematic diagram of the theoretical model of dual-beam emission of the implantable multi-brain region regulation hydrogel optical fiber device of the present invention, wherein 6-1 is a front view of groove 1, 6-2 is a front view of groove 2, is the angle between the hydrogel optical fiber and groove 1, is the angle between the hydrogel fiber and groove 2, λ1 is the incident light 1, λ2 is the incident light 2, 6-3 is the core of the hydrogel fiber, 6-4 is the cladding of the hydrogel fiber, and l1 is the distance between the two grooves;

[0053] Figure 7 Schematic diagram of an experiment in which the implantable multi-brain region regulation hydrogel fiber optic device of the present invention is implanted in a mouse brain region to collect optical signals. 7-1 is a light source, 7-2 is a circulator, 7-3 is a spectrometer, 7-4 is a PC terminal, 7-5 is a support frame, 7-6 is a hydrogel fiber optic device, 7-7 is a mouse experimental platform, and 7-8 is an experimental mouse.

[0054] Figure 8 Schematic diagram of the signal transmission and collection process of the implantable multi-brain region regulation hydrogel optical fiber device of the present invention;

[0055] Figure 9 This is a curve showing the change in expansion rate of the double-groove hydrogel optical fiber obtained in step S7 of Example 1 in PBS buffer as a function of immersion time;

[0056] Figure 10 The sensitivity test results of the double-groove hydrogel optical fiber obtained in step S7 of Example 1 and the hydrogel optical fiber without double-groove etching are shown;

[0057] Figure 11 The bending-resilience performance test results of the double-groove hydrogel optical fiber obtained in step S7 of Example 1 and the optical fiber without double-groove etching are shown;

[0058] Figure 12 The tensile performance test results of the double-groove hydrogel optical fiber obtained in step S7 of Example 1, commercial quartz optical fiber, and polymer optical fiber;

[0059] Figure 13 The graph shows the calcium signal expression of a single stimulation (the black horizontal line is the duration of LS (5.5 s), the gray line represents the time when LS starts, and the thick black line represents the time when the animal starts the escape-fight behavior). DETAILED DESCRIPTION

[0060] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0061] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. The intermediate value within any stated value or stated range, and each smaller range between any other stated value or intermediate value within the stated range, is also encompassed within the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0062] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0063] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be exemplary only.

[0064] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0065] The present invention provides a method for preparing an implantable multi-brain region regulating hydrogel optical fiber device, comprising the following steps:

[0066] S1. Mixing a core precursor solution and a photocuring agent solution to obtain a mixed solution; transferring the mixed solution to a mold, and performing a photocuring reaction under ultraviolet light irradiation to obtain a hydrogel core; rotating and pulling the hydrogel core in a cladding solution, and then soaking the hydrogel core in a calcium chloride solution after the rotation and pulling to form a cladding on the surface of the hydrogel core; and then vertically hanging the hydrogel core coated with the cladding to air-dry to obtain a hydrogel optical fiber;

[0067] S2. Based on the two different light-sensitive proteins selected when using light-sensitive proteins to light-stimulate neurons in different brain regions or neurons in different regions of the same brain region, two beams of probe light with different wavelengths are selected to be injected into the implantable multi-brain region regulation hydrogel optical fiber device. The refractive index of the core of the hydrogel optical fiber to the two beams of probe light with different wavelengths is tested, denoted as n1 and n2. The tangent angle between the groove and the hydrogel optical fiber is calculated based on the refractive index, denoted as and

[0068] S3, calculated according to step S2 and Etching two grooves on the hydrogel optical fiber to obtain a double-groove hydrogel optical fiber; wherein the etching depth of the groove having a smaller tangent angle with the hydrogel optical fiber is 100±10 μm, and the etching depth of the groove having a larger tangent angle with the hydrogel optical fiber is 200±10 μm;

[0069] S4. Connect the silicon chip to one end of the double-groove hydrogel optical fiber to suppress the emission from the end face of the hydrogel optical fiber, thereby obtaining the implantable multi-brain region regulating hydrogel optical fiber device.

[0070] As a preferred embodiment of the present invention, the preparation method has the following specific preparation steps:

[0071] S1. Prepare the core precursor solution: prepare the core precursor solution according to the raw material composition of the core precursor solution;

[0072] S2. Prepare a light curing agent solution: prepare a light curing agent solution according to the raw material composition of the light curing agent solution;

[0073] S3. Extracting and curing the hydrogel core: adding a light curing agent solution to a core precursor solution to obtain a mixed solution; injecting the mixed solution into a polytetrafluoroethylene tube and performing a light curing reaction under ultraviolet light irradiation; and extracting the light-cured core from the tube;

[0074] S4, coating the optical fiber cladding: prepare the cladding solution according to the raw material composition of the cladding solution; then, clamp the hydrogel core extracted in S3 with a binder clip and rotate and pull it in the cladding solution (the operation diagram of the rotation pulling is shown in FIG. Figure 1Specifically, the hydrogel fiber core is first immersed in the cladding solution for 10 seconds, then repeatedly pulled at a pulling speed of 1 cm / s for 30-35 times, and then immersed in a 10% calcium chloride solution for 2 minutes to promote the formation of a complete hydrogel fiber cladding by sodium alginate and calcium ions, thus completing the cladding coating process;

[0075] S5. Fiber stretching and air drying: Hang the fiber coated with the cladding in S4 in the air. After standing for 20 minutes, clamp the bottom of the fiber with a binder clip and let the binder clip fall freely. Continue to hang vertically and air dry for 6 hours (the operation diagram of vertical hanging fiber air drying is shown in the figure). Figure 2 shown);

[0076] S6. Calculation of the angle between the groove and the hydrogel fiber: Based on the two different light-sensitive proteins selected when using light-sensitive proteins to light-stimulate neurons in different brain regions or neurons in different regions of the same brain region, two beams of probe light with different wavelengths are selected to be injected into the implantable multi-brain region control hydrogel fiber device. The refractive index of the hydrogel fiber core to the two beams of probe light with different wavelengths is tested, denoted as n1 and n2. According to the refractive index and formula Calculate the tangent angle between the groove and the hydrogel fiber and

[0077] S7, double groove etching of hydrogel optical fiber: The hydrogel optical fiber after air drying in S5 was fixed with an optical fiber clamp, and then the optical fiber was fixed on the slide with tape. The position of the optical fiber was adjusted by a multi-axis angle adjustable platform, and the femtosecond laser micromachining system (laser wavelength 1028nm) and STL graphics calling function were used according to the calculated S6. and Double groove etching is performed with the groove depth corresponding to the cut angle (the etching depth of the groove with a smaller cut angle with the hydrogel optical fiber is 100±10μm, and the etching depth of the groove with a larger cut angle with the hydrogel optical fiber is 200±10μm) to obtain a double groove hydrogel optical fiber (the operation diagram of the double groove etching process is shown in FIG. Figure 3 The schematic diagram of the obtained double groove hydrogel is shown in Figure 5 shown);

[0078] S8. Suppressing the emission from the end face of the double-groove hydrogel optical fiber: Clean the silicon wafer with alcohol and acetone, cut it with a cutting blade after drying, screen the silicon wafer under a microscope, clean the screened silicon wafer with alcohol after screening, and bond one end of the double-groove hydrogel optical fiber to the silicon wafer to suppress the emission from the end face of the optical fiber (the operation diagram of the process of suppressing the emission from the end face of the optical fiber is shown in the figure). Figure 4 If the emission from the fiber end face is not suppressed, the optical signal may not be detected at the double groove.

[0079] The present invention also provides an implantable multi-brain region regulating hydrogel optical fiber device prepared by the above preparation method.

[0080] The present invention also provides the use of the above-mentioned implantable multi-brain region regulation hydrogel optical fiber device as an optical brain-computer interface to prepare a multi-brain region regulation device.

[0081] The implantable multi-brain region control hydrogel optical fiber device of the present invention satisfies the dual-beam emission theoretical model (see Figure 6 ), so that the two optical paths emit light stimulation of different wavelengths. The details are as follows:

[0082] For a medium with a refractive index of n, the cut angle is Assume that the angle between the incident light and the optical fiber is θ, then:

[0083]

[0084] When reflected on the cut plane, the reflection angle is To satisfy the total reflection condition, then: get:

[0085]

[0086] To prevent the second reflected light from emitting from the optical fiber, another range is obtained:

[0087]

[0088] In summary, the required cut angle to prevent light of any wavelength from emitting from the optical fiber in a medium with a refractive index of n is the exact value Therefore, for two beams of light with different refractive indices, grooves with different cutting angles are designed. The two beams of light can be separated and emitted at different grooves.

[0089] Based on the above theoretical analysis, it can be concluded that the feasibility of the dual-light path output application of the implantable multi-brain region regulation hydrogel optical fiber device of the present invention is proven, which proves that it has practical application potential for multi-brain region regulation.

[0090] The implantable multi-brain region regulating hydrogel optical fiber device of the present invention, its preparation method and application are further described below with reference to specific embodiments.

[0091] All raw materials and equipment used in the examples of the present invention were purchased from commercial sources. The polytetrafluoroethylene tube was purchased from DAOGUAN, with a length of 50 mm, an inner diameter of 2 mm, and an outer diameter of 2.2 mm. The small binder clip for holding the hydrogel optical fiber was purchased from Deli, with a clamp width of 15 mm. The culture dish was purchased from bkman, mainly made of polystyrene, with a total height of 14.85 mm, a bottom height of 13.2 mm, a bottom inner diameter of 85.32 mm, and a cap diameter of 90.24 mm. The syringe was purchased from Andermed Medical, with a specification of 5 mL and a registration number of National Medical Device Registration No. 20153141515. The materials for configuring the hydrogel fiber core and cladding were purchased from Macklin (https: / / www.macklin.cn) and Sinopharm Chemical Reagent Co., Ltd. (https: / / www.macklin.cn). / / www.reagent.com.cn) and Aladdin (https: / / www.aladdin-e.com), specifically containing acrylamide, deionized water, sodium alginate, anhydrous calcium chloride, N,N'-methylenebisacrylamide, ammonium persulfate, N,N,N',N'-tetramethylethylenediamine, ethanol, acetone, PBS buffer, 1% sodium pentobarbital solution, and Irgacure; the pipette was an Eppendorf single-channel pipette, with three sizes of 100-1000 μL, 10-100 μL, and 2-20 μL selected for the experiment; the pipette tip was a Biosharp sterile box pipette tip; the beaker was a Hinwell experimental beaker; the UV lamp model was Omnicure S1500, 320-500 nm output, Excelitas Canada Inc., and the irradiation power during the experiment was 107 mW / cm 2 The wavelength of illumination was 396 nm. The microinjector and needle were from Hamilan, the microinjection pump was from KDS, the stereotaxic instrument was from Reward, and the stainless steel screws were purchased from Reward.

[0092] The weighing processes involved in the embodiments are all performed using an electronic balance, and the liquid is measured using a single-channel pipette or a graduated cylinder.

[0093] Example 1

[0094] An implantable multi-brain region regulation hydrogel fiber optic device, the preparation steps are as follows:

[0095] S1. Prepare a fiber core precursor solution: dissolve 35% acrylamide, 0.5% N,N'-methylenebisacrylamide, and 1.5% ammonium persulfate in 63.00% deionized water by volume to obtain a fiber core precursor solution.

[0096] S2. Prepare a light curing agent solution: Mix 0.2% Irgacure with 99.8% deionized water by volume, and ultrasonically disperse for 30 minutes to obtain a light curing agent solution.

[0097] S3. Extract and cure the hydrogel core: Use a single-channel pipette to add 15 μL of the photocuring agent solution to the 5 mL of the core precursor solution prepared in S1, and stir with a glass rod for 10 seconds to obtain a mixed solution. Use a syringe to inject the mixed solution into a polytetrafluoroethylene tube with a length of 50 mm and an inner diameter of 2 mm. Place the polytetrafluoroethylene tube filled with the mixed solution under a UV lamp for 1 hour of photocuring (irradiation power of 107 mW / cm 2 , the illumination wavelength was 396nm). The cured PTFE tube was then opened and removed using an alcohol-cleaned cutting blade to extract the hydrogel core. To prevent core shape changes during the experiment, the extracted core was temporarily stored in a moistened Petri dish. During this step, while preparing the hydrogel core, a hydrogel sample with the same composition as the hydrogel core was prepared using the same photocuring process using the mixed solution. After air-drying (at room temperature for 6 hours), the sample was used to test its refractive index in response to two probe beams of different wavelengths.

[0098] S4. Coating the optical fiber cladding: Mix 1% EDC, 1.2% Sulfo-NHS, 20% sodium alginate, 0.05% TEMED and 77.75% deionized water in a culture dish to obtain a cladding solution. Clamp one end of the hydrogel core extracted from S3 with a binder clip and rotate and pull it in the cladding solution (the operation diagram is shown in the figure). Figure 1 Specifically, the hydrogel core was immersed in the cladding solution for 10 seconds, then pulled 30 times at a pulling speed of 1 cm / s. After each three pulls, the hydrogel core was rotated 360° clockwise around the culture dish in the cladding solution, maintaining a rotational speed of 180° / s. The entire rotational pulling process lasted 2-3 minutes. After the rotational pulling process, the core was immersed in a 10% calcium chloride solution for 2 minutes to promote the formation of a complete hydrogel fiber cladding by the sodium alginate and calcium ions.

[0099] S5. Stretch and air-dry the optical fiber: hang the hydrogel optical fiber (i.e., the hydrogel core coated with the cladding) in S4 vertically in the air. After standing for 20 minutes, clamp the bottom of the optical fiber (i.e., the other end) with a binder clip and let the binder clip fall freely. Air-dry at room temperature (23°C) for 6 hours (the operation diagram is shown in the figure). Figure 2 As shown), a hydrogel optical fiber with a double-layer structure is formed (the shape of the hydrogel optical fiber is a cylinder).

[0100] S6. Calculation of the angle between the groove and the hydrogel fiber: Based on the two different light-sensitive proteins (ChR2 and NpHR) selected when using light-sensitive proteins to perform light stimulation and regulation on neurons in different brain regions or neurons in different regions of the same brain region, two beams of probe light with different wavelengths are selected to be injected into the implantable multi-brain region regulation hydrogel fiber device. The wavelengths of the two beams of light are λ1 = 470nm (probe light that stimulates ChR2 in neurons in a certain region to activate neurons in that region, making that region a neuron-exciting brain region), and λ2 = 590nm (probe light that stimulates NpHR in neurons in another region to inhibit neurons in that region, making that region a neuron-inhibiting brain region). The core of the hydrogel fiber is measured using an Abbe refractometer (tested using the air-dried sample prepared separately in step S3). The refractive index of light of wavelengths λ1 and λ2 are n1 = 1.41 and n2 = 1.38, respectively. This result is consistent with the law of normal dispersion. According to the refractive index and the formula Calculate the cutting angle between the groove and the hydrogel fiber and get two different cutting angles The depths of the two grooves are selected to be different from the cut angles of the hydrogel optical fiber, where the cut angle is The corresponding depth of the groove is 200 μm, and the cutting angle is The corresponding depth of the groove is 100 μm.

[0101] S7, double groove etching of hydrogel optical fiber (operation diagram as shown in Figure 3 As shown in the figure): The hydrogel optical fiber of S5 is fixed on a glass slide, and the position of the optical fiber is adjusted using a six-axis precision translation stage. The wavelength of the femtosecond laser is set to 1028nm, the pulse energy is 0.2mJ, the pulse width is 120fs, and the repetition frequency is 1kHz. The femtosecond laser micromachining system and the STL graphics calling function are used to perform double groove etching according to the angle between the groove and the hydrogel optical fiber calculated by S6 and the depth of the selected groove in the hydrogel to obtain a double groove hydrogel optical fiber. After the etching is completed, the groove etching effect is observed using a microscope.

[0102] S8. Suppress the end-face emission of the double-groove hydrogel optical fiber (operation diagram as shown in the figure) Figure 4As shown): the silicon wafer is cleaned and dried with 75vol% alcohol and acetone, and then the silicon wafer is cut with a cutting blade. The cutting size is the same as the size of the end face of the hydrogel optical fiber. After the cutting is completed, the silicon wafer is placed in a 75vol% alcohol solution again for cleaning and drying. The silicon wafer is then connected and cured with the mixed solution in S3 to one end of the double-groove hydrogel optical fiber (specifically, the mixed solution in S3 is applied to one side of the silicon wafer and one end face of the double-groove hydrogel optical fiber, and the side of the silicon wafer coated with the mixed solution is bonded to the end face of the double-groove hydrogel optical fiber coated with the mixed solution, and then placed under a UV lamp for 1 hour of light curing with an irradiation power of 107mW / cm 2 , the light wavelength is 396nm), and after curing, the connection is immersed in the cladding solution prepared by S4 for 10s, and then immersed in a calcium chloride solution with a mass fraction of 10% for 2min, and then vertically hung to air dry, completing the cladding coating of the connection to achieve the suppression of the optical fiber end face emission, and obtaining a hydrogel optical fiber device (the schematic diagram of the hydrogel optical fiber device is shown in Figure 5 shown).

[0103] Through the above S1-S8, the preparation of the hydrogel optical fiber device is completed. After repeated preparation and experimental testing, the overall diameter (outer diameter) of the double-layer hydrogel optical fiber formed in S5 is 400±20μm, of which the core diameter is 350±10μm and the cladding thickness is 25±5μm. Before performing the double-groove etching in step S7, the appropriate double-groove hydrogel optical fiber length and the appropriate distance between the two grooves can be selected according to the size of the brain area of ​​the experimental animal and the distribution of the neurons to be regulated. In this embodiment, mice are used as experimental animals. The neurons to be photostimulated and regulated by ChR2 and NpHR are located in different areas of the ventral tegmental area. The length of the double-groove hydrogel optical fiber is selected to be 2cm, and the distance between the two grooves is 2mm (the distance between the right end point of the first groove and the left end point of the second groove). It can be ensured that the two beams of detection light are irradiated to the corresponding areas after passing through the double-groove hydrogel optical fiber device.

[0104] The implantable multi-brain region control hydrogel fiber optic device prepared by the present invention can record and perform closed-loop control of specific neurons in multiple brain regions of mice or different regions of the same brain region. The experimental schematic diagram of the implantable multi-brain region control hydrogel fiber optic device implanted in the mouse brain region to collect light signals is shown as follows: Figure 7 As shown in the figure, specifically, the sensor detection light source is transmitted to the hydrogel optical fiber device through a circulator to achieve optical stimulation of the brain area. The detection light containing brain area information is transmitted to the spectrometer through the circulator. After the optical signal is recorded, it is transmitted to the PC for processing and comprehensive analysis of brain area information, such as analysis of instinctive defense behavior, to achieve multi-brain area regulation. The schematic diagram of the entire signal transmission and collection process is shown in the figure. Figure 8 shown.

[0105] Taking the neural mechanism of neurons in different regions of the ventral tegmental area involved in visual instinctive defense response as an example, specific tests were conducted:

[0106] The experimental steps for mice are as follows:

[0107] ① Anesthesia of mice: Anesthetize with 100 mg of 1% sodium pentobarbital solution per kg of body weight. After anesthesia, apply erythromycin ointment to the mouse's eyeball to keep it moist and prevent corneal desiccation, thereby protecting the mouse's eyes.

[0108] ② Fixation and leveling: Use a stereotaxic instrument to fix the mouse. First, disinfect the mouse's scalp with 75% alcohol, then cut the scalp to expose the bregma and lambda on the skull. Measure the distance from Bregma to Lambda and record it as the AP (Anteroposterior) value. Take half of the AP value in the X-axis direction, set the Y-axis value to 1mm, and adjust the left and right ear bars of the stereotaxic instrument so that the Z-axis height is consistent; at the same time, adjust the incisor clamp to ensure that the height of Bregma and Lambda on the Z-axis (Dorsaventral, DV value) is also the same. According to these coordinates, drill a hole in the skull, clean the skull powder with a syringe filled with saline, and keep the skull hole moist.

[0109] ③Injection of CaMKlla-ChR2-mCherry and EF1a-NpHR3.0-EYFP viruses: Prepare a microinjector and needle and connect them to a microinjection pump. First draw enough paraffin oil, taking care to avoid bubbles during the process (injection speed is 150nL / s). Release 2 microliters of paraffin oil in advance to ensure smooth communication between the instrument, syringe and needle. Then, draw 1 microliter of 10 12 Virus particles / ml of CaMKlla-ChR2-mCherry virus solution and EF1a-NpHR3.0-EYFP virus solution, to ensure that there is no blockage and bubbles during the suction process. Slowly lower the needle to the position of the target nucleus DV value of about 0.6mm, and continue to lower it by 0.2mm at a slower speed, and stay for 5-8 seconds to allow the two virus solutions to penetrate and diffuse downward. After the injection is completed, move the needle up 0.2mm and stay for 5-8 seconds to allow the two virus solutions to penetrate and diffuse upward. After the virus injection is completed, apply lidocaine gel to the wound to relieve pain and prevent infection. After the animal wakes up, put it back in the cage. The expression time of the virus in the body varies depending on the type of virus, usually 4-6 weeks. The purpose of this step is to simultaneously introduce ChR2 and NpHR into specific neurons in this brain area.

[0110] ④ Fiber embedding: The steps of anesthetizing and fixing mice are the same as before. A hole is made at the predetermined coordinates of the fiber embedding brain area, and 3 holes are made near the fiber, and 3 stainless steel screws are implanted as a stable base for the dental cement bracket. An implantable hydrogel fiber optic device (prepared in Example 1, with a core diameter of 350 μm, a cladding thickness of 25 μm, a length of 2 cm before the silicon chip is not connected, and a distance of 2 mm between the two grooves) is implanted into the target brain area using a fiber optic clamp. The DV value is set to 0.1-0.4 mm higher than the virus injection point. By regulating the position of the hydrogel fiber optic device, two beams of detection light can be injected into two different areas to be regulated in the ventral tegmentum (denoted as area 1 and area 2, wherein area 1 is located on the posterior outer side of the ventral tegmentum and area 2 is located on the anterior inner side of the ventral tegmentum). After the optical fiber is in place, the screws and hydrogel fiber optic device are covered with mixed dental cement. After the dental cement is completely cured, the animal is awake and put back in the cage. The surgical recovery period is 5-7 days, after which subsequent experimental operations can be performed. Subsequent experiments used probes of 470nm and 590nm wavelengths to illuminate the implantable multi-brain region control hydrogel fiber optic device. The 470nm probe light was emitted from one groove and entered region 1, activating ChR2 in neurons there. The 590nm probe light was emitted from the other groove and entered region 2, activating NpHR in neurons there. Simultaneously with the two different wavelengths of probe light, a visual instinctive fear experiment was conducted to further illustrate the results.

[0111] ⑤Visual instinctive fear experiment process:

[0112] The present invention designs a cubic experimental box with three sides made of white frosted organic plastic panels and one side made of transparent organic plastic panels. Its dimensions are 40 cm long, 40 cm wide, and 25 cm high. A 17-inch LCD monitor is embedded in the top of the experimental box. In one corner of the box, a 10 cm wide and 15 cm high rectangular shelter is placed to simulate a mouse nest. A high-definition digital camera with a shooting speed of up to 25 frames per second is mounted on the transparent surface of the experimental box. On the day of the experiment, the mouse is placed in the experimental box and allowed to acclimate to the environment for 5 minutes. When the mouse moves into the quadrant diagonally opposite the nest, it is given a shadow "Looming" stimulus in its upper visual field. This stimulus is presented as a black dot with a 2° visual angle (approximately 0.6 cm radius) that gradually enlarges to a black disk with a 20° visual angle (approximately 12.25 cm radius). Each stimulus lasts 350 milliseconds and is repeated 16 times in total, with the entire process lasting approximately 5.6 seconds. The stimulus is administered by the experimenter manually pressing the spacebar. The interval between each stimulation was no less than 2 minutes.

[0113] ⑥Data analysis:

[0114] The results of multi-brain region regulation are mainly reflected through calcium signals. The processing method of calcium signal data is as follows: First, all the raw data are smoothed by the moving average method, where each smoothing window covers 5 data points. Next, the change in the fluorescence signal (the fluorescence signal generated by the activated ChR2 and NpHR) is calculated, and the calculation formula used is (F-Fo) / Fo. The Fo here refers to the average value of the background fluorescence signal within 2 seconds before the excitation event. In order to perform these calculations and analyses, we used the OpSignal multi-channel Matlab analysis software developed by Qianaoxingke. Through this software, we can load event data files and calcium signal data files, and then draw a curve graph of (F-Fo) / Fo. The relevant results are shown in Figure 13 The figure shows that the calcium signal response increases in latency with the onset of LS stimulation and continues to increase until the animal initiates escape-fight behavior. Analysis of instinctive defensive behavior suggests that the implantable multi-brain region control hydrogel fiber optic device of the present invention, through stimulation with 470nm and 590nm probe light, activates and inhibits neurons in different regions of the mouse ventral tegmental area.

[0115] Effect verification

[0116] The performance of the double-groove hydrogel optical fiber obtained in step S7 of Example 1 of the present invention was compared with that of other different optical fibers (hydrogel optical fiber without double-groove etching, PMMA optical fiber, and quartz optical fiber) to verify its performance. To make all experimental results more representative, each experimental process was repeated three times. The hydrogel optical fiber without double-groove etching used in the experiment was the hydrogel optical fiber obtained in step S5 of Example 1 before double-groove etching. The PMMA optical fiber and quartz optical fiber used were both common commercial products. Among them, the PMMA (polymethyl methacrylate) optical fiber (POFXCL) had an overall diameter of 400 μm, and the quartz optical fiber (HPCF400) had a core diameter of 400 μm and a cladding thickness of 15 μm (i.e., the overall outer diameter of the optical fiber was 430 μm).

[0117] 1. Hydrogel optical fiber swelling performance test

[0118] The double-groove hydrogel optical fiber obtained in step S7 of the embodiment was subjected to a swelling performance test. Before immersing the double-groove hydrogel optical fiber in a culture dish filled with PBS buffer, its mass was weighed using a balance and recorded as the initial mass of the double-groove hydrogel optical fiber (w0). Subsequently, it was immersed in PBS buffer, maintaining the water temperature at 30°C, and at intervals of 30, 60, 90, 120, 150, and 300 minutes. The double-groove hydrogel optical fiber was gently taken out, the surface moisture was absorbed with filter paper, and the weight was recorded as the mass of the double-groove hydrogel optical fiber after immersion (w0).t ). Calculate its swelling ratio SR. The calculation formula of the swelling ratio is shown in formula (4):

[0119]

[0120] Test results see Figure 9 ,from Figure 9 It can be seen that after being immersed in PBS buffer for 150 minutes, the swelling rate is basically maintained at 150-160%, indicating that the double-groove hydrogel optical fiber obtained in step S7 of Example 1 of the present invention has high fidelity and will not destroy the integrity of the hydrogel optical fiber due to the moist environment in the brain.

[0121] 2. Sensitivity test

[0122] The double-groove hydrogel optical fiber obtained in step S7 of Example 1 and the hydrogel optical fiber without double-groove etching obtained in step S5 were used for pressure sensitivity testing. The two different hydrogel optical fibers were placed on a pressure platform one after another, and a pressure of 0.1N was applied each time. The change in light intensity was recorded using a spectrometer. In order to better show the change in light intensity with applied pressure, the test light intensity was normalized. The test results are shown in FIG. Figure 10 As shown in the figure, by performing linear fitting on the test results, it was found that the sensitivity of the double-groove hydrogel optical fiber was -0.89±0.03, and the sensitivity of the hydrogel optical fiber without double-groove etching was -0.47±0.04. After double-groove etching, the sensitivity was increased by nearly double, which fully demonstrated the superiority of double-groove hydrogel optical fiber in practical applications. The higher sensitivity ensures that it can accurately capture brain area information and achieve precise multi-brain area regulation.

[0123] 3. Bending resilience test

[0124] The double-grooved hydrogel optical fiber obtained in step S7 of Example 1 and the hydrogel optical fiber without double-grooved etching obtained in step S5 were used for bending resilience testing. The two hydrogel optical fibers were fixed on a rotation stage, which was then rotated 90° clockwise for 500 rotations. The angular deviation of the optical fiber when it returned to its initial position compared to when it was not rotated was recorded every 100 rotations. The test results are shown in Figure 2. Figure 11 As shown in the figure, the maximum bending angle deviation of the double-groove hydrogel optical fiber is 9±1°, and the maximum bending angle deviation of the hydrogel optical fiber without double-groove etching is 18±1.5°. From this result, it can be seen that the bending angle deviation of the hydrogel optical fiber with double-groove etching is small, which fully demonstrates its good durability, facilitates long-term brain area information monitoring, realizes accurate multi-brain area regulation, and has good practical application potential.

[0125] 4. Tensile performance test

[0126] The double-groove hydrogel optical fiber obtained in step S7 of Example 1 was selected to test the relationship between applied tension and deformation with PMMA optical fiber and quartz optical fiber. When performing the tensile test, the three optical fibers were fixed on the tensile machine in turn, different tensile forces were applied, and the relationship between tension and deformation was recorded. The test results are shown in Figure 2. Figure 12 As shown, from Figure 12 As can be seen from the figure, the double-groove hydrogel fiber obtained in step S7 of Example 1 exhibits the best tensile performance. When the applied stress is 56.4±1.2N, its tensile strain reaches 18%. In contrast, the PMMA fiber and the quartz fiber break at 5.5% and 4% stretch, respectively. This indicates that the double-groove hydrogel fiber obtained in step S7 of Example 1 has better tensile performance than PMMA and quartz fibers and has great potential for practical applications. In addition to its high biocompatibility, it also exhibits strong flexibility, a large tensile limit, strong durability, and a soft texture.

[0127] In summary, compared with other optical fibers, the implantable multi-brain region regulation hydrogel optical fiber device of the present invention has the potential to achieve long-term multi-brain region regulation and brain region neural recording, has high practical potential, and has great biomedical value.

[0128] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for preparing an implantable multi-brain region regulation hydrogel optical fiber device, characterized in that: The following steps are involved: S1, mixing a core precursor solution and a photocuring agent solution to obtain a mixed solution; Transferring the mixed solution into a mold and performing a photocuring reaction under ultraviolet light irradiation to obtain a hydrogel fiber core; The hydrogel fiber core is subjected to rotational pulling in a cladding solution, and then immersed in a calcium chloride solution after the rotational pulling to form a cladding on the surface of the hydrogel fiber core, and then the hydrogel fiber core coated with the cladding is vertically hung and air-dried to obtain a hydrogel optical fiber; S2. Based on the two different light-sensitive proteins selected when using light-sensitive proteins to photostimulate neurons in different brain regions or neurons in different regions of the same brain region, select two beams of probe light with different wavelengths to be injected into the implantable multi-brain region regulation hydrogel fiber device, test the refractive index of the hydrogel fiber core for the two probe light beams with different wavelengths, denoted as n1 and n2, and calculate the tangent angle between the groove and the hydrogel fiber based on the refractive index, denoted as φ1 and φ2; S3. Etching two grooves on the hydrogel optical fiber according to φ1 and φ2 calculated in step S2 to obtain a double-groove hydrogel optical fiber; wherein the etching depth of the groove having a smaller tangent angle with the hydrogel optical fiber is 100±10 μm, and the etching depth of the groove having a larger tangent angle with the hydrogel optical fiber is 200±10 μm; S4. Connect the silicon chip to one end of the double-groove hydrogel optical fiber to suppress emission from the optical fiber end face, thereby obtaining the implantable multi-brain region regulating hydrogel optical fiber device.

2. The preparation method according to claim 1, wherein The specific operation of the rotation pulling is: first soaking the hydrogel fiber core in the cladding solution for 10 seconds, and then repeatedly pulling it 30-35 times at a pulling speed of 1 cm / s.

3. The preparation method according to claim 1, wherein The specific operation of vertically hanging the clad hydrogel fiber core to air-dry is as follows: fix one end of the clad hydrogel fiber core with a tool, hang it vertically in the air, let it stand for 20 minutes, fix the other end of the clad hydrogel fiber core with a tool, let the tool fall freely, and continue to hang it vertically to air-dry for 6 hours.

4. The preparation method according to claim 1, wherein The angle between the groove and the hydrogel optical fiber is calculated according to the formula calculate.

5. The preparation method according to claim 1, wherein The etching is performed by a femtosecond laser micromachining system, and the etching wavelength is 1028 nm.

6. The preparation method according to claim 1, wherein The specific operation of connecting the silicon chip to one end of the double-groove hydrogel optical fiber is: using the mixed solution described in step S1 to connect and solidify the silicon chip and one end of the hydrogel optical fiber, and after solidification, using the cladding solution described in step S1 to clad the connection.

7. An implantable multi-brain region regulating hydrogel optical fiber device prepared by the preparation method according to any one of claims 1 to 6.

8. Use of the implantable multi-brain region control hydrogel optical fiber device as claimed in claim 7 as an optical brain-computer interface to prepare a multi-brain region control device.

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