A biological adhesive tape for a nerve stump after amputation and a preparation method thereof

Abstract

The application discloses a biological adhesive tape for a nerve stump after amputation and a preparation method thereof. The biological adhesive tape comprises an outer layer and an inner layer, and the outer layer and the inner layer are connected by a PEG-based adhesive layer. The outer surface of the outer layer is coated with a PDMS hydrophobic coating layer. The inner surface of the inner layer is also coated with a PEG-based adhesive layer. The outer layer is made of recombinant human collagen type I and contains dexamethasone drug-loaded microspheres. The inner layer is made of recombinant human collagen type I and contains gabapentin drug-loaded microspheres. The outer layer of the biological adhesive tape can inhibit inflammatory response and reduce foreign body reaction by releasing glucocorticoids. The inner layer can prevent and relieve neuropathic pain by releasing gabapentin. The physical adhesion of the adhesive tape can prevent the growth of nerve fibers outward, thereby reducing the risk of neuroma formation. The biological adhesive tape has high flexibility in application, is suitable for nerve stumps with different diameters and shapes, and is suitable for complex trauma.

Description

Technical Field

[0001] The present invention relates to the technical field of biomedicine, and in particular to a biological adhesive tape for nerve stumps after amputation and a preparation method thereof. Background Art

[0002] In recent years, the number of amputees worldwide has shown a significant upward trend. In the United States alone, there are currently approximately 1.7 million amputees, with over 230,000 new amputees discharged annually. However, approximately 25% of amputees are unable to begin rehabilitation or resume daily activities due to persistent pain in their residual limb. This pain primarily stems from neuromas and phantom limb pain in the nerve stump. Current clinical treatments include traction nerve resection or embedding the nerve stump in muscle or bone drill holes and suturing it. However, these surgical methods have numerous drawbacks, including high surgical difficulty.

[0003] Existing bioimplants include biodegradable polymer nerve tubes (such as Polyganics NEUROCAP) or stented nerve closure tubes (such as AXOGEN NerveCap). However, these nerve sheaths require epineurial sutures under a microscope during surgery using 8-0 sutures, which can easily leave residual thread and continue to stimulate the axons, making the procedure difficult. Furthermore, different diameter nerves require different sheath specifications, making clinical application cumbersome. Summary of the Invention

[0004] The purpose of the present invention is to provide a biological tape for nerve stumps after amputation and a preparation method thereof in view of the deficiencies in the prior art.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] The first aspect provides a bioadhesive tape for use on nerve stumps after amputation, comprising an outer layer and an inner layer, wherein the outer layer and the inner layer are connected by a layer of PEG-based adhesive, wherein the outer surface of the outer layer is coated with a PDMS hydrophobic coating; and the inner surface of the inner layer is also coated with a PEG-based adhesive layer.

[0007] The outer layer is made of recombinant human type I collagen and contains dexamethasone-loaded microspheres made of PEG-PLGA copolymer; dexamethasone is used to inhibit inflammatory reactions and reduce foreign body reactions;

[0008] The inner layer is made of recombinant human type I collagen and contains gabapentin-loaded microspheres made of PEG-PLA copolymer; gabapentin is used to prevent and relieve neuralgia;

[0009] The PEG-based adhesive is formed by cross-linking four-arm PEG-acrylate and dithiothreitol.

[0010] Among them, the matrix material uses recombinant human type I collagen, which has good biocompatibility; the drug-loaded microspheres use PEG-PLGA and PEG-PLA copolymers to achieve slow release of drugs.

[0011] Furthermore, the average particle size of the dexamethasone-loaded microspheres is 4-5 μm.

[0012] Furthermore, the average particle size of the gabapentin-loaded microspheres is 2-3 μm.

[0013] Furthermore, the thickness of the outer layer is 0.4-0.5 mm, and the thickness of the inner layer is 0.8-1 mm.

[0014] The second aspect is to provide a method for preparing the above-mentioned biological tape for nerve stumps after amputation, comprising the following steps:

[0015] Step 1, preparing the outer layer solution and the inner layer solution respectively;

[0016] Step 2: pour the inner layer solution into a mold and crosslink at 35-37°C for 0.5-1 hour;

[0017] Step 3, evenly coating the inner and outer surfaces of the cross-linked inner layer with a PEG-based adhesive;

[0018] Step 4: Pour the outer layer solution onto the inner layer and cross-link at 35-37°C for 0.5-1 hour;

[0019] Step 5: coating a PDMS hydrophobic layer on the outer surface after cross-linking;

[0020] Step six, vacuum drying for 10-12 hours and sterilization to obtain the biological tape for nerve stumps after amputation.

[0021] Furthermore, the specific preparation method of the inner layer solution is as follows:

[0022] Gabapentin-loaded microspheres were prepared by spray drying: gabapentin and PEG-PLA copolymer were dissolved in dichloromethane and the microspheres were prepared using a spray dryer with an inlet temperature of 70°C, an outlet temperature of 40°C, and a pump speed of 5 mL / min. The gabapentin-loaded microspheres were collected and freeze-dried.

[0023] The gabapentin-loaded microspheres were dispersed in a recombinant human type I collagen solution with a concentration of 12 mg / mL, and stirred at 37° C. for 1 hour to uniformly disperse the microspheres.

[0024] Furthermore, the specific preparation method of the outer layer solution is as follows:

[0025] Dexamethasone-loaded microspheres were prepared using a double emulsion method: dexamethasone and PEG-PLGA copolymer were dissolved in dichloromethane to form the oil phase. The oil phase was slowly added dropwise to a 2% w / w PVA aqueous solution and ultrasonically emulsified using an ultrasonic probe to form colostrum. The colostrum was slowly poured into a 0.5% w / w PVA aqueous solution, stirred to evaporate the solvent, and the dexamethasone-loaded microspheres were collected by centrifugation and freeze-dried.

[0026] Dexamethasone-loaded microspheres were dispersed in a recombinant human type I collagen solution with a concentration of 8 mg / mL and stirred at 37°C for 1 hour to uniformly disperse the microspheres.

[0027] Furthermore, the PEG-based adhesive was prepared as follows: four-arm PEG-acrylate was dissolved in PBS solution, dithiothreitol was added, and the mixture was reacted at 37°C for 30 minutes to form a hydrogel. The PEG-based hydrogel ensured good adhesion between the adhesive tape and the nerve stump.

[0028] Furthermore, the specific operation of coating the PDMS hydrophobic layer on the surface of the outer layer is as follows: dissolving the PDMS prepolymer in n-hexane, coating the outer layer surface by spin coating (to ensure uniformity), and curing at 80°C for 2 hours to form a PDMS hydrophobic layer to prevent scar tissue deposition.

[0029] The present invention adopts the above technical solution, which has the following technical effects compared with the prior art:

[0030] The bio-tape of this invention has an outer (non-stick) layer that slowly releases glucocorticoids to suppress inflammation and reduce foreign body reactions, while the inner (adhesive) layer slowly releases gabapentin to prevent and relieve neuralgia. Furthermore, the physical adhesion of the tape prevents outgrowth of nerve fibers, thereby reducing the risk of neuroma formation.

[0031] In addition, the bio-tape of the present invention has low application difficulty, simple clinical application, high application flexibility, is suitable for nerve stumps of different diameters and shapes, is suitable for complex trauma situations, and can cover multiple nerve stumps and surrounding damaged tissues. DETAILED DESCRIPTION

[0032] The present invention will be further described below with reference to specific embodiments, but this is not intended to limit the present invention. It should be noted that, unless there is a conflict, the embodiments and features in the embodiments of the present invention may be combined with each other.

[0033] Experimental reagents and instruments:

[0034] Recombinant human type I collagen, Shanxi Jinbo Biopharmaceutical Co., Ltd., China;

[0035] Acetic acid solution, Sigma-Aldrich, USA;

[0036] Dexamethasone, Sigma-Aldrich, USA;

[0037] Dichloromethane, Merck, Germany;

[0038] PEG-PLGA copolymer, LA:GA=75:25, Mw=20 kDa, Evonik, Germany;

[0039] PVA, Sigma-Aldrich, USA;

[0040] Gabapentin, Sigma-Aldrich, USA;

[0041] PEG-PLA copolymer, Mw = 15 kDa, Polysciences, USA;

[0042] Four-arm PEG-acrylate, molecular weight 10 kDa, Laysan Bio, USA;

[0043] PBS solution, pH = 7.4, Gibco, USA;

[0044] Dithiothreitol, DTT, Sigma-Aldrich, USA;

[0045] PDMS prepolymer, Dow Corning, USA;

[0046] n-Hexane, Sigma-Aldrich, USA;

[0047] Ultrasound probe, Sonics & Materials, USA;

[0048] Freeze drying equipment, FreeZone series, Labconco, USA;

[0049] Spray dryer, B-290, BUCHI, Switzerland;

[0050] PTFE mold, custom made, Shanghai Jinpan Medical Instrument Co., Ltd., China;

[0051] Spin coater, WS-650, Laurell Technologies, USA;

[0052] Vacuum drying oven, DZF-6050, Shanghai Yiheng Scientific Instrument Co., Ltd., China.

[0053] Example 1

[0054] This embodiment provides a biological tape for use on nerve stumps after amputation. The specific preparation method is as follows:

[0055] 1. Preparation of Required Solutions

[0056] 1.1 Preparation of inner layer solution

[0057] Gabapentin-loaded microspheres were prepared by spray drying: 500 mg of gabapentin and 1 g of PEG-PLA copolymer were dissolved in 100 mL of dichloromethane. Microspheres were prepared using a spray dryer (inlet temperature 70°C, outlet temperature 40°C, pump rate 5 mL / min), collected, and freeze-dried for 24 hours.

[0058] 1 g of gabapentin-loaded microspheres were dispersed in 100 mL of recombinant human type I collagen solution (12 mg / mL) and stirred at 37°C for 1 hour to uniformly disperse the microspheres.

[0059] The solvent of the recombinant human type I collagen solution is 0.1 M acetic acid solution.

[0060] 1.2 Preparation of outer layer solution

[0061] Dexamethasone-loaded microspheres were prepared using a double emulsion method (W / O / W): 200 mg of dexamethasone and 100 mg of PEG-PLGA copolymer were dissolved in 10 mL of dichloromethane as the oil phase. The oil phase was slowly added dropwise to 10 mL of a 2 w / w% PVA aqueous solution. Ultrasonic emulsification was performed using an ultrasonic probe for 5 minutes (power 300 W, 2 seconds on, 1 second interval) to form colostrum. The colostrum was slowly poured into 100 mL of a 0.5% PVA aqueous solution and stirred for 4 hours (400 rpm) to evaporate the solvent. The microspheres were collected by centrifugation (10,000 g, 10 minutes) and freeze-dried for 24 hours.

[0062] 1 g of dexamethasone-loaded microspheres were dispersed in 100 mL of recombinant human type I collagen solution (8 mg / mL) and stirred at 37°C for 1 hour to uniformly disperse the microspheres.

[0063] The solvent of the recombinant human type I collagen solution is 0.1 M acetic acid solution.

[0064] 1.3 Preparation of PEG-based adhesive

[0065] 2 g of four-arm PEG-acrylate was dissolved in 10 mL of PBS solution, and 15.4 mg of dithiothreitol was added and reacted at 37°C for 30 minutes to form a hydrogel.

[0066] 2. Preparation of Biotape

[0067] 1) Pour the inner layer solution into a polytetrafluoroethylene mold with a thickness of 1 mm and crosslink at 37°C for 1 hour;

[0068] 2) Evenly apply 0.5 mL of PEG-based adhesive on the inner surface;

[0069] 3) Pour the outer layer solution onto the inner layer to a thickness of 0.5 mm and crosslink at 37°C for 1 hour;

[0070] 4) Coating the outer layer with a hydrophobic PDMS layer: PDMS prepolymer (components A and B of the curing agent Sylgard 184 were weighed in a 10:1 mass ratio) was dissolved in n-hexane to obtain a 5% (w / v) PDMS solution. A layer of PDMS was applied to the outer layer by spin coating (3000 rpm, 30 seconds) and cured at 80°C for 2 hours.

[0071] 5) Place in a vacuum drying oven and dry at 50°C for 12 hours;

[0072] 6) Sterilize with ethylene oxide gas at a temperature of 54° C., a relative humidity of 60%, an ethylene oxide concentration of 600 mg / L, and a sterilization time of 4 hours to obtain a biological tape for use on nerve stumps after amputation.

[0073] Application Example 1

[0074] After amputation, the biotape prepared in Example 1 can be used in the following manner according to the specific condition of the nerve stump:

[0075] 1. Fitting: For smaller nerve stumps (e.g., less than 5 mm), cut the bio-tape to the appropriate size, center the nerve stump on the tape, and then fold the tape in half so that the inner layer (adhesive layer) completely wraps around the nerve stump. Gently press to ensure full contact between the tape and the nerve stump.

[0076] 2. Wrapping and Fitting: For larger nerve stumps (e.g., greater than 5 mm) or irregularly shaped, cut the bio-tape into strips and wrap them around one end of the nerve stump, ensuring a 50% overlap with each wrap until the nerve stump is completely covered. Maintain appropriate tension during wrapping to ensure the tape adheres snugly to the nerve stump without causing compression.

[0077] 3. Complex trauma: For complex trauma with multiple nerve stumps or surrounding tissue damage, the two methods above can be combined as needed. First, each nerve stump is treated individually, and then a larger area of ​​tape can be used to cover the entire trauma area to provide additional protection and drug release.

[0078] Through these application methods, the bio-adhesive tape of the present invention can be applied to nerves of varying diameters and complex traumatic conditions. The outer layer (non-stick layer) slowly releases glucocorticoids to suppress inflammation and reduce foreign body reactions, while the inner layer (adhesive layer) slowly releases gabapentin to prevent and relieve neuralgia. Furthermore, the physical adhesion of the tape prevents outgrowth of nerve fibers, thereby reducing the risk of neuroma formation. During application, care should be taken to maintain the sterility of the surgical area.

[0079] Verification Example 1

[0080] In order to simulate the sustained release of two drugs (dexamethasone and gabapentin) in the biotape prepared in Example 1 under an in vitro environment, the present invention placed the biotape film sample in PBS buffer for a sustained release experiment, and measured the released drug concentration at a fixed time point using high performance liquid chromatography, and finally obtained the sustained release data at different time points.

[0081] 1. Experimental Conditions

[0082] Buffer: PBS (phosphate buffered saline), pH = 7.4

[0083] Temperature: 37℃±0.5℃

[0084] Stirring speed: 100 rpm

[0085] Sampling time points: 0h, 2h, 4h, 8h, 12h, 24h, 48h, 72h, 96h, 120h, 168h; sampling 3 times at each time point, and repeated experiments 3 times

[0086] Experimental film size: 1cm×1cm; thickness: 1.5mm

[0087] PBS buffer volume: Use 50 mL of PBS buffer and place it in a 100 mL beaker

[0088] 2. Drug concentration determination method: High performance liquid chromatography (HPLC)

[0089] The chromatographic conditions are:

[0090] Chromatographic column: C18 reverse phase column (150mm×4.6mm, 5μm)

[0091] Mobile phase:

[0092] Dexamethasone: acetonitrile: water = 60:40 (v / v)

[0093] Gabapentin: methanol: 0.05 M potassium dihydrogen phosphate buffer (pH 6.5) = 20:80 (v / v)

[0094] Flow rate: 1.0 mL / min

[0095] Detection wavelength: dexamethasone 240nm; gabapentin 210nm

[0096] Injection volume: 20 μL

[0097] Sampling method: 1 mL of sample was taken at each time point, and 1 mL of fresh PBS was immediately added after sampling to keep the volume constant.

[0098] 3. Dexamethasone sustained-release data (unit: cumulative release percentage)

[0099] Time point | Release percentage (mean ± SD)

[0100] 0h|0%±0%

[0101] 2h|5.2%±0.8%

[0102] 4h|9.7%±1.2%

[0103] 8h|18.3%±1.5%

[0104] 12h|25.6%±1.9%

[0105] 24h|38.4%±2.3%

[0106] 48h | 52.7% ± 2.8%

[0107] 72h | 63.5% ± 3.1%

[0108] 96h|72.1%±3.4%

[0109] 120h|78.9%±3.6%

[0110] 168h|85.3%±3.8%

[0111] visible:

[0112] 1) The release rate was relatively fast in the first 24 hours, with a cumulative release of 38.4%;

[0113] 2) The release rate flattened out from 24 to 72 hours, and the cumulative release increased from 38.4% to 63.5%;

[0114] 3) The release rate further slowed down from 72 to 168 hours, and the final cumulative release reached 85.3%;

[0115] 4) After 168 hours (7 days), the cumulative release reached 85.3%, indicating that most of the drug had been released, but about 15% of the drug still remained in the carrier.

[0116] 4. Gabapentin sustained-release data (unit: cumulative release percentage)

[0117] Time point | Release percentage (mean ± SD)

[0118] 0h|0%±0%

[0119] 2h|7.8%±1.1%

[0120] 4h | 14.5% ± 1.6%

[0121] 8h|25.9%±2.0%

[0122] 12h|35.2%±2.4%

[0123] 24h|49.7%±2.9%

[0124] 48h | 65.3% ± 3.3%

[0125] 72h | 76.8% ± 3.6%

[0126] 96h|84.5%±3.8%

[0127] 120h|90.2%±4.0%

[0128] 168h|94.7%±4.1%

[0129] visible:

[0130] 1) The release rate was relatively fast in the first 24 hours, with a cumulative release of 49.7%;

[0131] 2) The release rate slowed slightly from 24 to 72 hours, and the cumulative release increased from 49.7% to 76.8%;

[0132] 3) The release rate further slowed down from 72 to 168 hours, and the final cumulative release reached 94.7%;

[0133] 4) After 168 hours (7 days), the cumulative release reached 94.7%, indicating that almost all the drugs were released and only about 5% of the drugs remained in the carrier.

[0134] Verification Example 2

[0135] To test the effectiveness of the biotape of the present invention, we conducted a series of in vivo experiments:

[0136] 2.1 Selection of experimental animals:

[0137] Adult male Sprague-Dawley rats weighing 250-300 g were selected.

[0138] 2.2 Group design:

[0139] The rats were randomly divided into 2 groups, 6 in each group, and samples were collected at 4 time points;

[0140] Control group: only sciatic nerve transection

[0141] Experimental group: Sciatic nerve was cut and then wrapped with the biotape of the present invention

[0142] 2.3 Evaluation Metrics

[0143] Neuroma formation assessment: Assess the incidence of neuromas.

[0144] The criteria for positive neuroma formation are:

[0145] (1) Gross observation: Obvious spherical or spindle-shaped swelling appears at the nerve stump, with the diameter of the swelling exceeding 1.5 times the normal nerve diameter. Histological observation: HE staining shows disordered nerve fiber arrangement, obvious collagen fiber proliferation, and disordered axon regeneration, with a "whorl-like" or "maze-like" arrangement. Immunohistochemistry: Positive staining of nerve fiber markers (such as NF200) shows disordered distribution, and increased expression of collagen fiber markers (such as type I collagen).

[0146] (2) Scar formation assessment: Masson trichrome staining was used to observe the thickness and density of collagen fibers.

[0147] (3) Evaluation of anti-inflammatory effect: Western blot was used to detect the expression of inflammatory factors (IL-1β, TNF-α).

[0148] 2.4 Experimental Results

[0149] 1) Incidence of neuroma

[0150] Time point | Neuroma incidence in the control group | Neuroma incidence in the experimental group

[0151] 2 weeks | 33.3% (2 / 6) | 0% (0 / 6)

[0152] 4 weeks | 66.7% (4 / 6) | 0% ( / 6)

[0153] 8 weeks | 100% (6 / 6) | 0% (0 / 6)

[0154] 12 weeks | 100% (6 / 6) | 0% (0 / 6)

[0155] 2) Collagen fiber thickness and density

[0156] Time point | Collagen fiber thickness of control group (μm) | Collagen fiber thickness of experimental group (μm) | Collagen fiber density of control group (%) | Collagen fiber density of experimental group (%) (mean ± SD)

[0157] 2 weeks|52.3±5.1|38.6±4.2|35.7±3.8|27.9±3.1

[0158] 4 weeks | 78.5 ± 7.3 | 54.2 ± 5.7 | 48.3 ± 4.5 | 36.2 ± 3.7

[0159] 8 weeks | 95.7±8.9 | 67.3±6.5 | 57.6±5.2 | 42.8±4.3

[0160] 12 weeks | 108.2 ± 10.1 | 75.9 ± 7.2 | 63.4 ± 5.8 | 47.5 ± 4.6

[0161] 3) Expression levels of inflammatory factors in Western blot experiments

[0162] Time point|Control group IL-1β (relative expression)|Experimental group IL-1β (relative expression)|

[0163] TNF-α(relative expression) in control group | TNF-α(relative expression) in experimental group (mean ±

[0164] Standard Deviation

[0165] 2 weeks|2.87±0.31|1.95±0.22|2.53±0.28|1.76±0.19

[0166] 4 weeks|2.41±0.26|1.52±0.17|2.12±0.23|1.38±0.15

[0167] 8 weeks|1.93±0.21|1.14±0.13|1.75±0.19|1.05±0.11

[0168] 12 weeks|1.56±0.17|0.89±0.10|1.43±0.16|0.82±0.09

[0169] The above data show that the biological tape prepared by the present invention can effectively inhibit the formation of neuroma after nerve transection, reduce the generation of scar tissue, and reduce local inflammatory response.

[0170] The above description is only a preferred embodiment of the present invention and does not limit the implementation mode and protection scope of the present invention. Those skilled in the art should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the contents of the present invention specification should be included in the protection scope of the present invention.

Claims

1. A biological tape for nerve stumps after amputation, characterized in that: The invention comprises an outer layer and an inner layer, wherein the outer layer and the inner layer are connected by a layer of PEG-based adhesive, the outer surface of the outer layer is coated with a PDMS hydrophobic coating, and the inner surface of the inner layer is also coated with a PEG-based adhesive layer; Wherein, the outer layer is made of recombinant human type I collagen and contains dexamethasone-loaded microspheres, and the dexamethasone-loaded microspheres are made of PEG-PLGA copolymer; The inner layer is made of recombinant human type I collagen and contains gabapentin-loaded microspheres, which are made of PEG-PLA copolymer; The PEG-based adhesive is formed by cross-linking four-arm PEG-acrylate and dithiothreitol.

2. The biological tape for nerve stumps after amputation according to claim 1, characterized in that: The average particle size of the dexamethasone-loaded microspheres is 4-5 μm.

3. The biological tape for nerve stumps after amputation according to claim 1, characterized in that: The average particle size of the gabapentin-loaded microspheres is 2-3 μm.

4. The biological tape for nerve stumps after amputation according to claim 1, characterized in that The thickness of the outer layer is 0.4-0.5 mm, and the thickness of the inner layer is 0.8-1 mm.

5. A method for preparing a biological tape for nerve stumps after amputation according to any one of claims 1 to 4, characterized in that: The steps include: Step 1, preparing the outer layer solution and the inner layer solution respectively; Step 2: pour the inner layer solution into a mold and crosslink at 35-37°C for 0.5-1 hour; Step 3, evenly coating the inner and outer surfaces of the cross-linked inner layer with a PEG-based adhesive; Step 4: Pour the outer layer solution onto the inner layer and cross-link at 35-37°C for 0.5-1 hour; Step 5: coating a PDMS hydrophobic layer on the outer surface after cross-linking; Step six, vacuum drying for 10-12 hours and sterilization to obtain the biological tape for nerve stumps after amputation.

6. The preparation method according to claim 5, characterized in that The specific preparation method of the inner layer solution is as follows: Gabapentin-loaded microspheres were prepared by spray drying: gabapentin and PEG-PLA copolymer were dissolved in dichloromethane and the microspheres were prepared using a spray dryer with an inlet temperature of 70°C, an outlet temperature of 40°C, and a pump speed of 5 mL / min. The gabapentin-loaded microspheres were collected and freeze-dried. The gabapentin-loaded microspheres were dispersed in a recombinant human type I collagen solution with a concentration of 12 mg / mL, and stirred at 37° C. for 1 hour to uniformly disperse the microspheres.

7. The preparation method according to claim 5, characterized in that The specific preparation method of the outer layer solution is as follows: Preparation of dexamethasone-loaded microspheres: Dexamethasone and PEG-PLGA copolymer were dissolved in dichloromethane to form the oil phase. The oil phase was slowly added dropwise to a 2% w / w PVA aqueous solution and ultrasonically emulsified using an ultrasonic probe to form colostrum. The colostrum was slowly poured into a 0.5% w / w PVA aqueous solution, stirred to evaporate the solvent, and the dexamethasone-loaded microspheres were collected by centrifugation and freeze-dried. Dexamethasone-loaded microspheres were dispersed in a recombinant human type I collagen solution with a concentration of 8 mg / mL and stirred at 37°C for 1 hour to uniformly disperse the microspheres.

8. The preparation method according to claim 5, characterized in that The specific preparation method of the PEG-based adhesive is as follows: four-arm PEG-acrylate is dissolved in PBS solution, dithiothreitol is added, and the mixture is reacted at 37°C for 30 minutes to form a hydrogel.

9. The preparation method according to claim 5, characterized in that The specific operation of coating the PDMS hydrophobic layer on the surface of the outer layer is as follows: PDMS prepolymer is dissolved in n-hexane, coated on the surface of the outer layer by spin coating, and cured at 80°C for 2 hours to form the PDMS hydrophobic layer.