A microneedle patch for treating spinal cord injury and preparation method thereof

Abstract

The present invention provides a microneedle patch for treating spinal cord injury and a preparation method thereof, comprising a silk fibroin microneedle and mesoporous organic silicon oxide nanoparticles filled inside the silk fibroin microneedle, and preparing the microneedle patch by mixing the amination-modified mesoporous organic silicon oxide nanoparticles loaded with ammonia borane with a silk fibroin solution. The technical solution of the present invention can significantly improve the recovery effect after spinal cord injury by locally regulating the iron ion concentration and the oxidative stress level, which not only solves the technical defects of the existing microneedle patch technology in the specific treatment of spinal cord injury, but also provides a new type of treatment device with practical application potential.

Description

Technical Field

[0001] The present invention relates to the field of medical materials and equipment, and in particular to a microneedle patch for treating spinal cord injury and a preparation method thereof. Background Art

[0002] Current approaches to treating spinal cord injury include drug therapy to reduce inflammation and oxidative damage, and physical therapy to promote functional recovery. However, these approaches generally fail to directly regulate the microenvironment of the injured area.

[0003] In the prior art, conventional microneedle patch technology is used for drug delivery, as shown in U.S. Patent No. US20140350123A1. These microneedle patches achieve rapid drug release by physically penetrating the skin barrier. However, although conventional microneedle patches provide an effective way to deliver drugs, they do not provide a solution for the specific biochemical environment in spinal cord injury - iron ion accumulation.

[0004] Furthermore, these approaches also fail to generate beneficial hydrogen gas in the local microenvironment to alleviate the oxidative stress caused by iron ions. Summary of the invention

[0005] In view of the problems in the prior art, the object of the present invention is to provide a microneedle patch for treating spinal cord injury and a preparation method thereof.

[0006] According to one aspect of the present invention, a microneedle patch for treating spinal cord injury is provided, comprising silk fibroin microneedles and mesoporous organic silicon oxide nanoparticles filled inside the silk fibroin microneedles.

[0007] Preferably, the mesoporous organic silicon oxide nanoparticles are amino-modified mesoporous organic silicon oxide nanoparticles.

[0008] Preferably, the surface of the mesoporous organic silicon oxide nanoparticles is loaded with ammonia borane.

[0009] Preferably, the mass ratio of the ammonia borane to the aminated mesoporous organic silicon oxide nanoparticles is 1:1-10.

[0010] Preferably, the mass ratio of the silk fibroin microneedles to the amino-modified mesoporous organic silicon oxide nanoparticles loaded with ammonia borane is 5 to 30:1.

[0011] Preferably, the particle size of the mesoporous organic silicon oxide nanoparticles is 50-120 nm, and the pore size is 1-8 nm.

[0012] Preferably, the amination is carried out by treating the surface of the mesoporous organic silicon oxide nanoparticles with 3-aminopropyltriethoxysilane.

[0013] Preferably, the silk fibroin microneedle comprises a plurality of microneedles, the distance between the centers of adjacent microneedles is 600-800 μm, the radius of the bottom of the microneedle is 70-90 μm, and the height of the microneedle is 250-300 μm.

[0014] According to another aspect of the present invention, a method for preparing the above-mentioned microneedle patch for treating spinal cord injury is provided, comprising the following steps:

[0015] Step 1, preparing amino-modified mesoporous organic silicon oxide nanoparticles;

[0016] Step 2, preparing amino-modified mesoporous organic silicon oxide nanoparticles with ammonia borane loaded on the surface;

[0017] Step 3, preparing a silk fibroin solution, mixing the amino-modified mesoporous organic silicon oxide nanoparticles loaded with ammonia borane with the silk fibroin solution to prepare a microneedle patch.

[0018] Preferably: Step 1 comprises:

[0019] Step 1.1, preparing an ethanol solution of mesoporous organic silicon oxide nanoparticles;

[0020] Step 1.2, adding 3-aminopropyltriethoxysilane to the ethanol solution of the mesoporous organic silicon oxide nanoparticles, centrifuging the reaction, and washing to obtain the amino-modified mesoporous organic silicon oxide nanoparticles.

[0021] The present invention provides a microneedle patch for treating spinal cord injury and a preparation method thereof, which can significantly improve the recovery effect after spinal cord injury by locally regulating the iron ion concentration and oxidative stress level. In this way, the present invention not only solves the technical defects of the existing microneedle patch technology in the specific treatment of spinal cord injury, but also provides a new type of treatment device with practical application potential. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Other features, objectives and advantages of the present invention will become more apparent from a reading of the detailed description of non-limiting embodiments made with reference to the following accompanying drawings.

[0023] Figure 1a TEM image of amino-modified mesoporous silica according to an embodiment of the present invention;

[0024] Figure 1b This is a TEM image of the amination-modified mesoporous silica loaded with ammonia borane according to an embodiment of the present invention;

[0025] Figure 1c This is an element distribution diagram of the amination-modified mesoporous silica loaded with ammonia borane according to an embodiment of the present invention;

[0026] Figure 1d This is a SEM image of the microneedle loaded with MON@AB according to an embodiment of the present invention;

[0027] Figure 1e This is a gas chromatogram of hydrogen release from the MON@AB loaded microneedles according to an embodiment of the present invention;

[0028] Figure 2a This is a Prussian blue iron staining image of a normal spinal cord according to an embodiment of the present invention;

[0029] Figure 2b This is a Prussian blue iron staining image of the SCI spinal cord in an embodiment of the present invention;

[0030] Figure 2c This is a picture of the SCI spinal cord Lucia blue iron staining after microneedle treatment of MON@AB according to an embodiment of the present invention;

[0031] Figure 3a A normal mouse gait motion diagram according to an embodiment of the present invention;

[0032] Figure 3b The gait motion diagram of the SCI mouse according to the embodiment of the present invention;

[0033] Figure 3c This is a gait motion diagram of SCI mice after microneedle treatment of MON@AB according to an embodiment of the present invention;

[0034] Figure 4a This is a display diagram of the pressure intensity of the normal mouse hind limbs according to an embodiment of the present invention;

[0035] Figure 4b This is a graph showing the pressure intensity of the hind limbs of an SCI mouse according to an embodiment of the present invention;

[0036] Figure 4c This is a graph showing the pressure intensity of the hind limbs of SCI mice after microneedle treatment with MON@AB according to an embodiment of the present invention;

[0037] Figure 5a This is an immunofluorescence staining image of a normal spinal cord according to an embodiment of the present invention (red NF-200 neural structure marker, green GAFP glial scar marker, yellow PLP myelin marker);

[0038] Figure 5b This is an immunofluorescence staining image of the SCI spinal cord of an embodiment of the present invention;

[0039] Figure 5c This is an immunofluorescence staining image of the SCI spinal cord after microneedle treatment of MON@AB in an embodiment of the present invention;

[0040] Figure 6 This is an infrared spectrum of the amino-modified mesoporous silicon according to an embodiment of the present invention. DETAILED DESCRIPTION

[0041] Example embodiments will now be described more fully with reference to the accompanying drawings. However, example embodiments can be implemented in a variety of forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present invention will be comprehensive and complete and fully convey the concepts of the example embodiments to those skilled in the art. The same reference numerals in the figures represent the same or similar structures, and thus their repeated description will be omitted.

[0042] In an embodiment of the present invention, a microneedle patch for treating spinal cord injury is provided:

[0043] The iron ion adsorption and hydrogen production microneedle patch for treating spinal cord injury (referred to as "microneedle patch") includes silk fibroin microneedles that can be degraded in the body and mesoporous organic silicon oxide (mesoporous silica) nanoparticles (MON) filled inside the microneedles.

[0044] Preferably, MON is treated with amination and the surface of MON is loaded with hydrogen donor ammonia borane (AB)

[0045] That is, the internal space between the microneedles is filled with the degradable MON@AB complex.

[0046] The iron ion adsorption and hydrogen production microneedle patch for treating spinal cord injury in the embodiment of the present invention combines amino-modified MON with good biosafety, hydrogen donor AB and degradable silk fibroin microneedles.

[0047] Silk fibroin microneedles have good biological safety and tissue repair function and can serve as a good carrier of MON@AB.

[0048] Traditional microneedle patches are not designed to adsorb iron ions, resulting in the inability to effectively reduce oxidative stress caused by iron ion accumulation due to spinal cord injury. The embodiments of the present invention can adsorb iron ions in the damaged area by introducing mesoporous organic silicon oxide nanoparticles into the microneedles, thereby directly reducing oxidative damage and cell death. This improvement has a significant improvement in chemical adsorption efficiency, which is specifically reflected in the increase in the value of adsorption capacity, which will be directly reflected in the improvement of therapeutic effect. Aminated MON has an extremely high specific surface area and drug loading rate. At the same time, the amino groups grafted on the surface of mesoporous silicon can selectively adsorb iron ions and have excellent divalent iron adsorption capacity, while mesoporous silicon without amino has no ability to adsorb iron ions.

[0049] Existing microneedle technology lacks the function of producing hydrogen in the local treatment area. Hydrogen, as a known antioxidant, can effectively reduce oxidative stress. The microneedle patch of the embodiment of the present invention can produce hydrogen in the body environment by loading ammonia borane in the mesoporous organic silicon oxide nanoparticles, which helps to further inhibit lipid peroxidation and cell death caused by iron ion accumulation. The hydrogen donor AB can decompose and produce hydrogen in the slightly acidic environment of inflammation in the body, achieving sustained release in the body. Amination MON can carry ammonia borane into the damaged area, release hydrogen while efficiently adsorbing divalent iron ions, and blocking the process of ferroptosis.

[0050] Preferably, in an embodiment of the present invention, the mass ratio of ammonia borane to amination-modified mesoporous organic silicon oxide nanoparticles in the microneedles is preferably 1:1 to 10. And the mass ratio of silk fibroin microneedles to ammonia borane-loaded ammonia borane-modified mesoporous organic silicon oxide nanoparticles is preferably 5 to 30:1.

[0051] In an embodiment of the present invention, a method for preparing a microneedle patch for treating spinal cord injury is also provided, comprising the following steps:

[0052] Step 1: synthesize amino-modified mesoporous organic silica nanoparticles (MON) using a template method.

[0053] Dissolve cetyltrimethylammonium chloride and triethanolamine in deionized water.

[0054] Tetraethoxysilane and bis-[3-(triethoxysilyl)propyl]tetrasulfide were added dropwise, and the mixture was stirred.

[0055] The product was collected by centrifugation and washed with ethanol and water for several times to remove residual reactants.

[0056] Then, the collected product was extracted with a hydrochloric acid solution in ethanol (10% v / v), and the template hexadecyltrimethylammonium chloride was removed by reflux to obtain mesoporous organic silica nanoparticles MON.

[0057] Subsequently, the surface of MON was treated with 3-aminopropyltriethoxysilane to react with amine groups. MON was first dispersed in ethanol, and then the solution was refluxed and 3-aminopropyltriethoxysilane was added. After centrifugation, it was washed with water and ethanol, and the amine-functionalized MON (MON-NH2) was redispersed in ethanol to obtain an amino-modified mesoporous organic silicon oxide nanoparticle solution.

[0058] The particle size of the finally prepared amino mesoporous organic silicon oxide nanoparticles is 50-120 nm, preferably 100 nm, and the pore size is 1-8 nm, preferably 5 nm. 2+ The adsorption rate reaches over 60%.

[0059] The mesoporous silica nanoparticles used in the embodiments of the present invention have a specific pore size and surface functionalization treatment, which enables them to effectively adsorb iron ions and stably release hydrogen under in vivo conditions. This solves the problem that traditional microneedle patches cannot effectively intervene in the accumulation of iron ions in the spinal cord injury area. Through both physical and chemical mechanisms, mesoporous silica nanoparticles play a key role in the treatment of spinal cord injury, both adsorbing iron ions and alleviating oxidative stress.

[0060] Step 2, modifying the surface of the amino mesoporous organic silicon oxide nanoparticles with a hydrogen donor AB to obtain MON@AB;

[0061] The aminated mesoporous organic silica nanoparticles and AB were mixed in deionized water and stirred in an ice water bath.

[0062] MON@AB (aminated mesoporous organic silicon oxide nanoparticles loaded with ammonia borane) was obtained by vacuum drying.

[0063] Ammonia borane is loaded into mesoporous silica nanoparticles, which enable stable and controlled generation of hydrogen in vivo. This overcomes the limitation of existing treatment methods that cannot directly produce antioxidants in the damaged area. The generation of hydrogen provides a strong antioxidant protection directly at the damaged site, reducing cell ferroptosis and lipid peroxidation.

[0064] Step 3: Wrap the MON@AB as a whole in the silk fibroin microneedles to prepare a microneedle patch for iron ion adsorption and hydrogen production.

[0065] The use of silk fibroin as the matrix material of the microneedle not only provides good biocompatibility and biodegradability, but also enhances the mechanical strength of the microneedle and the stability of the drug carrier. The common biocompatibility problems and limited drug loading of traditional microneedle patch materials are solved in the present invention. The use of silk fibroin matrix makes the microneedle patch more suitable for long-term contact with the organism, and can effectively load high concentrations of mesoporous silica nanoparticles and ammonia borane.

[0066] Polydimethylsiloxane (PDMS) is used as the basic mold for preparing microneedle patches. The microneedles in the center of the mold are arranged in a 12×12 array, the distance between the centers of adjacent microneedles is 600-800μm, the bottom radius of the microneedles is 70-90μm, and the height of the microneedles is 250-300μm. The bottom of the microneedle patch is a 10mm×10mm rectangle.

[0067] Traditional microneedle patches may not be able to effectively penetrate the skin to reach the spinal cord injury area. The microneedle design optimization of the embodiment of the present invention ensures that the therapeutic agent can be accurately delivered to the spinal cord injury area, thereby improving the therapeutic effect.

[0068] MON@AB was mixed with silk fibroin solution (purchased from Suzhou Yongqinquan, EFL-SilMA-001). The mixture was absorbed by a pipette and added to the needle groove of the PDMS mold and dried and irradiated.

[0069] The silk fibroin solution is then absorbed, added to a mold for drying, irradiation, and demoulding to obtain a microneedle patch.

[0070] A microneedle patch for treating spinal cord injury and a preparation method thereof according to an embodiment of the present invention can significantly improve the recovery effect after spinal cord injury by locally regulating the iron ion concentration and oxidative stress level. In this way, the embodiment of the present invention not only solves the technical defects of the existing microneedle patch technology in the specific treatment of spinal cord injury, but also provides a new type of treatment device with practical application potential.

[0071] The present invention is described below with specific embodiments:

[0072] Example 1

[0073] Step 1, dissolve 2 g of hexadecyltrimethylammonium chloride and 1 g of triethanolamine in 20 ml of deionized water at 95° C. with stirring.

[0074] After 20 minutes, 1 g of tetraethoxysilane and 1.3 g of bis-[3-(triethoxysilyl)propyl]tetrasulfide were added dropwise, and the mixture was stirred for 4 hours.

[0075] The product was collected by centrifugation and washed with ethanol and water for several times to remove residual reactants.

[0076] Then, the collected product was extracted with hydrochloric acid solution in ethanol (10% v / v) at 78° C. for 12 hours, and the extraction was repeated twice. The template hexadecyltrimethylammonium chloride was removed by reflux to obtain mesoporous organic silica nanoparticles MON.

[0077] Subsequently, the surface of MON was treated with 3-aminopropyltriethoxysilane to react with amine groups. First, 50 mg of MON was dispersed in 100 mL of ethanol, and then the solution was refluxed at 78 ° C for 12 hours, and then 50 μL of 3-aminopropyltriethoxysilane was added to react for 6 hours. After centrifugation, it was washed with water and ethanol, and the amine-functionalized MON (MON-NH2) was redispersed in 50 mL of ethanol to obtain an amino-modified mesoporous organic silica nanoparticle solution.

[0078] like Figure 6 The infrared spectrum of amino mesoporous silica is shown in Figure 1, where 690 and 1630 cm -1 Corresponding to the N—H bending vibration peak and —NH 3+The symmetrical vibration peaks of silane indicate that the surface of silica is successfully modified by silane. The particle size of the amino-modified mesoporous organic silicon oxide nanoparticles prepared is 100nm and the pore size is 5nm. 2+ The adsorption rate reaches over 60%.

[0079] Step 2: 5 mg of amino-modified mesoporous organic silica nanoparticles and 2 mg of AB were mixed in 10 mL of deionized water and stirred in an ice-water bath for 3 days.

[0080] MON@AB (aminated mesoporous organic silicon oxide nanoparticles loaded with ammonia borane) was obtained by vacuum drying.

[0081] Step 3, using polydimethylsiloxane (PDMS) as the basic mold for preparing the microneedle patch. The microneedles in the center of the mold are arranged in an array of 12×12, the distance between the centers of adjacent microneedles is 800μm, the bottom radius of the microneedles is 90μm, and the height of the microneedles is 260μm. The bottom of the microneedle patch is a rectangle of 10mm×10mm.

[0082] MON@AB was mixed with silk fibroin solution (purchased from Suzhou Yongqinquan, EFL-SilMA-001). The mass ratio of MON@AB to silk fibroin was 1:9. 200 μL of the mixture was absorbed by a pipette, added to the pin groove of the PDMS mold and dried at 35 °C for 4 hours, followed by ultraviolet irradiation for 30 seconds.

[0083] Then absorb 500 μL of silk fibroin solution, add it into the mold and dry it for 4 hours, irradiate it with ultraviolet light for 30 seconds, and demold it to obtain the microneedle patch.

[0084] Experimental test:

[0085] 1. Hydrogen release test:

[0086] The microneedle patch prepared in Example 1 was placed in PBS with a pH of 6.5, and hydrogen gas was collected at 37° C. (normal body temperature) after 1, 20, and 30 minutes of reaction, respectively, and the gas production was detected by gas chromatograph.

[0087] Depend on Figure 1a It can be seen that amino-modified mesoporous silica with uniform size and good dispersion was synthesized.

[0088] Depend on Figure 1b and 1c It can be seen that ammonia borane is loaded into mesoporous silicon, and nitrogen and boron elements are evenly distributed.

[0089] Depend on Figure 1d It can be seen that MON@AB-loaded silk fibroin microneedles were synthesized, and the needle tip morphology was good.

[0090] Depend on Figure 1e It can be seen that through gas chromatography detection, the microneedle patch system can release hydrogen.

[0091] 2. The developed microneedle patch was used to treat a spinal cord injury (SCI) mouse model to evaluate its adsorption effect on iron ion accumulation at the injury site.

[0092] Animal model: Experimental mice for constructing a spinal cord injury model.

[0093] Patch: The microneedle patch prepared in Example 1 was applied to the spinal cord injury area.

[0094] Staining method: Prussian blue and DAB staining are used to mark and observe the distribution of iron ions.

[0095] Control group category:

[0096] Sham group: uninjured mice.

[0097] SCI group: untreated spinal cord injury model mice.

[0098] MON@AB group: mice treated with ammonia borane-loaded mesoporous silica microneedle patch.

[0099] Experimental steps:

[0100] Modeling: First, spinal cord injury model was established in experimental mice.

[0101] Patch application: The microneedle patch prepared in Example 1 was applied to the spinal cord injury site of experimental mice.

[0102] Staining and detection:

[0103] Prussian blue was used to stain the iron ion accumulation area to observe the changes in iron ion concentration.

[0104] DAB staining was used to further demonstrate the distribution of iron ions.

[0105] Measurement method:

[0106] Observe the staining results under a microscope and compare the color intensity of the areas where iron ions have accumulated.

[0107] Microscopic images were taken after staining of each group of animals for quantitative analysis and comparison.

[0108] Result description:

[0109] Figure 2a , 2b Figure 2c shows the spinal cord cross-section staining results of the three groups of experimental mice. The staining images show the distribution changes of iron ions. Figure 2a As shown in Figure 2, iron ions were sparsely distributed in the Sham group, with no obvious accumulation. Figure 2b As shown in Figure 2, the staining results of the SCI group showed that iron ions accumulated in large quantities in the injured area. Figure 2c As shown in the figure, compared with the SCI group, the distribution of iron ions in the experimental mice treated with the microneedle patch was significantly reduced in the MON@AB group, indicating that the microneedle patch has an adsorption effect on iron ions, and the MN / MON@AB group significantly reduced the accumulation of iron ions.

[0110] As shown in the figure, within 48 hours after treatment, the iron ion concentration in the damaged area of ​​the treatment group was reduced by more than 50% compared with the untreated group. This significant reduction helped alleviate oxidative stress and created a more favorable environment for cell and tissue recovery.

[0111] 3. Experiments to help spinal cord injured mice recover motor function and histology:

[0112] (1) The Catwalk gait analysis system was used to evaluate the kinematic function of the spinal cord injury model mice, which were divided into three groups: Sham group (uninjured), SCI group (untreated spinal cord injury), and MON@AB group (treated with microneedle patches).

[0113] like Figure 3a-3c As shown in the figure, mice can walk naturally on the gait track, and the system automatically records the gait information of mice, including the location of footprints, stride, step length and other parameters. Through video capture, the system analyzes the gait trajectory of each group of experimental mice. The stride distance of 0.5s, 0.75s, and 1.0s walking is recorded.

[0114] like Figure 3a As shown in , the sham group had a smooth gait, regular footstep intervals, and consistent stride length and speed, indicating good motor function; Figure 3b As shown in , the SCI group showed obvious asymmetry, unstable stride, and decreased coordination between the front and rear paws, indicating severe impairment of motor function; Figure 3c As shown in , the MON@AB group showed significantly improved gait compared with the SCI group, with increased stride length and better restoration of gait symmetry, indicating a therapeutic effect.

[0115] (2) The Catwalk system was used to record the magnitude (z-axis height represents pressure intensity) and distribution (x and y axes represent distribution in different areas of the sole) of the mouse hind limb pressure, e.g. Figure 4a-4c As shown in the figure, the pressure at each contact point on the sole of the foot is displayed in different colors and heights, representing the intensity of the pressure.

[0116] like Figure 4a As shown in , the Sham group showed normal bipedal pressure with a clear peak; Figure 4b As shown in , the SCI group had almost no significant pressure peak, indicating that the hindlimb function was severely impaired; Figure 4cAs shown in , the MON@AB group showed a certain pressure peak, indicating that the treatment effect was significant and the hind limb function was partially restored.

[0117] (3) Immunofluorescence staining was used to evaluate the effects of different treatment groups on tissue repair after spinal cord injury, especially on myelin, glial fibers, and nerve fibers. Figure 5a-5c As shown in the figure, PLP (yellow): represents myelin protein, a marker of myelin sheath, used to evaluate the repair and regeneration of myelin sheath. GAFP (green): represents glial fibrillary acid protein, a marker of astrocytes, used to reflect glial cell response, usually accompanied by inflammatory response and scar formation. NF-200 (red): represents neurofilament protein, a marker of nerve fibers, used to show the structural integrity and regeneration of nerve axons.

[0118] like Figure 5a As shown in the figure, the sham group (sham operation group): the overall staining image shows that the spinal cord structure is clear, the myelin sheath (PLP, yellow) is evenly distributed, and the myelin sheath structure is complete. The enlarged image shows that the myelin sheath tissue is not damaged, the nerve fibers (NF-200, red) are clear, and the astrocytes (GAFP, green) are less distributed, indicating that there is no obvious damage to the tissue and inflammatory response.

[0119] like Figure 5b As shown in the figure, the SCI group (untreated spinal cord injury group): Overall staining: Myelin (yellow) is significantly reduced, and myelin loss and tissue structure destruction can be seen in the injured area. Nerve fibers (red) are more broken, and astrocytes (green) are densely distributed, indicating a significant inflammatory response after injury. The enlarged image shows: In the injured area, myelin is severely lost, glial fibers proliferate, and the nerve fiber structure is damaged, showing breakage and uneven distribution, reflecting severe injury and inflammation.

[0120] like Figure 5c As shown in the figure, MON@AB group (microneedle patch treatment group): Overall staining: The myelin sheath (yellow) in the injured area increased significantly, indicating the regeneration effect of myelin sheath after treatment. The distribution of glial cells (green) was relatively uniform, and the nerve fibers (red) were partially restored, showing signs of tissue repair. The enlarged image shows that compared with the SCI group, myelin sheath regeneration increased, glial cells decreased, and the continuity of nerve fibers was partially restored, indicating that after using the microneedle patch, the myelin sheath and nerve fibers in the injured area were partially repaired, and the inflammatory response was also reduced.

[0121] In summary, for the regeneration of nerve fibers and myelin sheaths: In the treatment group, significant regeneration of nerve fibers and myelin sheaths was observed by fluorescent labeling of PLP and NF-200. Compared with the untreated group, the continuity of nerve fibers and the density of myelin sheath structure in the treatment group improved by about 60%, showing significant repair of nerve axons and myelin sheaths.

[0122] Regarding changes in glial cell responses: Results using GAFP labeling showed that astrocyte activity in the treatment group was significantly reduced, and glial proliferation and inflammatory responses were reduced by approximately 40% compared to the untreated group, which helps to reduce scar formation and promote regeneration of neural tissue.

[0123] For comprehensive tissue recovery: Comprehensive evaluation showed that the recovery of the structure and function of the spinal cord injury area in the treatment group was significantly better than that in the untreated group. Histological analysis showed that the cell survival rate and cell functionality in the treatment area were significantly improved, and the recovery of the overall tissue structure was improved by more than 50% compared with the untreated group.

[0124] As can be seen from the above, the embodiments of the present invention show significant beneficial effects in improving the treatment effect of spinal cord injury, reducing side effects, simplifying operation procedures, reducing costs, etc. These advantages make the present invention have high market potential and practical value, and help improve the treatment experience and prognosis of patients with spinal cord injury.

[0125] 1. Improve treatment efficiency and accuracy

[0126] The embodiments of the present invention directly act on the spinal cord injury area by designing a specific nano-microneedle patch, effectively concentrating the therapeutic force, and greatly improving the treatment accuracy and efficiency compared to traditional treatment methods (such as systemic drug administration).

[0127] 2. Reduce drug side effects and improve biosafety

[0128] Since the drug acts directly on the target area, systemic drug distribution is reduced, thereby reducing potential side effects. In addition, silk fibroin and mesoporous silica, as biocompatible materials, further improve the safety of treatment.

[0129] 3. Simplify treatment procedures and improve patient convenience

[0130] The microneedle patch of the embodiment of the present invention is easy to apply and remove, and does not require complicated surgical intervention, which greatly simplifies the treatment process. For patients, this treatment method is more convenient and less painful. In preclinical experiments, the patch treatment of the present invention can be completed in just a few minutes, while traditional drug injections or surgical operations take tens of minutes to hours.

[0131] 4. Environmentally friendly and cost-effective

[0132] Since the drug acts directly on the injured part, the total amount of the drug used is reduced compared to the traditional method, thereby reducing drug waste and environmental burden in the production process. At the same time, it reduces the pharmaceutical cost and the patient's treatment cost. According to preliminary economic evaluation, the treatment cost of the present invention is about 30% lower than that of traditional drug treatment.

[0133] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the protection scope of the present invention.

Claims

1. A microneedle patch for treating spinal cord injury, characterized in that: The invention comprises a silk fibroin microneedle and mesoporous organic silicon oxide nanoparticles filled in the silk fibroin microneedle.

2. The microneedle patch for treating spinal cord injury according to claim 1, characterized in that: The mesoporous organic silicon oxide nanoparticles are amino-modified mesoporous organic silicon oxide nanoparticles.

3. The microneedle patch for treating spinal cord injury according to claim 2, characterized in that: Ammonia borane is loaded on the surface of the mesoporous organic silicon oxide nanoparticles.

4. The microneedle patch for treating spinal cord injury according to claim 3, characterized in that: The mass ratio of the ammonia borane to the amino-modified mesoporous organic silicon oxide nanoparticles is 1:1-10.

5. The microneedle patch for treating spinal cord injury according to claim 3, characterized in that: The mass ratio of the silk fibroin microneedles to the amino-modified mesoporous organic silicon oxide nanoparticles loaded with ammonia borane is 5 to 30:

1.

6. The microneedle patch for treating spinal cord injury according to claim 1, characterized in that: The particle size of the mesoporous organic silicon oxide nanoparticles is 50-120 nm, and the pore size is 1-8 nm.

7. The microneedle patch for treating spinal cord injury according to claim 2, characterized in that: The amination is carried out by treating the surface of the mesoporous organic silicon oxide nanoparticles with 3-aminopropyltriethoxysilane.

8. The microneedle patch for treating spinal cord injury according to claim 1, characterized in that: The silk fibroin microneedle comprises a plurality of microneedles, the distance between the centers of adjacent microneedles is 600-800 μm, the bottom radius of the microneedle is 70-90 μm, and the height of the microneedle is 250-300 μm.

9. A method for preparing the microneedle patch for treating spinal cord injury according to claim 3, characterized in that: The following steps are involved: Step 1, preparing amino-modified mesoporous organic silicon oxide nanoparticles; Step 2, preparing amino-modified mesoporous organic silicon oxide nanoparticles with ammonia borane loaded on the surface; Step 3, preparing a silk fibroin solution, mixing the amino-modified mesoporous organic silicon oxide nanoparticles loaded with ammonia borane with the silk fibroin solution to prepare a microneedle patch.

10. The method for preparing a microneedle patch for treating spinal cord injury according to claim 9, characterized in that: The step 1 comprises: Step 1.1, preparing an ethanol solution of mesoporous organic silicon oxide nanoparticles; Step 1.2, adding 3-aminopropyltriethoxysilane to the ethanol solution of the mesoporous organic silicon oxide nanoparticles, centrifuging the reaction, and washing to obtain the amino-modified mesoporous organic silicon oxide nanoparticles.

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