A microneedle / gelma hydrogel composite hernia patch and a preparation method thereof

Abstract

The application discloses a microneedle / GelMA hydrogel composite hernia patch and a preparation method thereof, the patch comprising a microneedle array layer and a GelMA hydrogel, the GelMA hydrogel covering and adhering to the root of the microneedle needle. The microneedle array layer is used for realizing tissue fixation and local drug delivery, the GelMA hydrogel is enzymatically crosslinked by an HRP / H2O2 system to form a stable structure, and has good flexibility and wet adhesion performance. The application combines the biodegradability and tissue integration characteristics of type IV collagen and the adjustable mechanics and biological adhesion characteristics of the GelMA hydrogel, realizes a minimally invasive, stable and degradable hernia repair scheme, can be firmly attached to the tissue surface without suturing, can be gradually degraded and absorbed after the operation, reduces foreign body reaction and organ adhesion, significantly reduces the risk of infection and recurrence, and has excellent biocompatibility and clinical application prospect.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of biotechnology, and particularly relates to a microneedle / GelMA hydrogel composite hernia patch and a preparation method thereof. BACKGROUND

[0002] Hernia repair surgery is one of the surgical treatment methods commonly used in clinical practice. Traditional repair usually relies on materials such as polypropylene patches and polyester fiber meshes. Although such materials have good mechanical strength, they have poor surface hydrophilicity and limited biocompatibility, which can easily cause postoperative infection, inflammatory reaction, and abdominal organ adhesion and other complications. In addition, traditional patches are usually fixed by suturing or stapling, which not only increases the wound area and operation time, but also can cause postoperative pain and patch displacement.

[0003] In recent years, hydrogel materials have been widely studied for tissue repair due to their good biocompatibility, degradability, and wet adhesion. However, pure hydrogels are insufficient in mechanical support and fixation ability and are difficult to withstand abdominal wall tension. On the other hand, microneedle technology, as a new emerging minimally invasive interface penetration method, can achieve local drug release and mechanical anchoring, but traditional microneedles are mostly made of polymers or metals, which have limitations such as slow degradation and residual risk. In summary, existing hernia repair materials still cannot simultaneously meet the requirements of biocompatibility, antibacterial property, anti-adhesion property, and tissue fixation stability.

[0004] Therefore, a microneedle / GelMA hydrogel composite hernia patch and a preparation method thereof are urgently needed. SUMMARY

[0005] To solve the defects in the prior art, the application provides a microneedle / GelMA hydrogel composite hernia patch and a preparation method thereof, to solve the problems of poor tissue compatibility, unstable fixation, and high risk of postoperative complications of existing hernia repair materials.

[0006] To solve the above technical problems, the application provides the following technical solutions:

[0007] The first object of the application provides a microneedle / GelMA hydrogel composite hernia patch, which comprises a microneedle array layer and a GelMA hydrogel. The microneedle array layer is composed of type IV collagen and is shaped by freeze-drying. The front surface of the microneedle array layer has a plurality of microneedle tips. The GelMA hydrogel is formed by enzymatic cross-linking and solidification of the HRP / H2O2 system. The GelMA hydrogel covers and adheres to the root of the microneedle tip.

[0008] Preferably, the length of the microneedle tip of the microneedle array layer is 400-800 pm, and the arrangement density is 10x10-20x20 needles / cm 2 .

[0009] Preferably, the thickness of the GelMA hydrogel is 0.8mm-1.5mm.

[0010] Preferably, the tissue contact surface of the GelMA hydrogel is provided with an anti-adhesion coating.

[0011] The second object of the present application provides a preparation method of a microneedle / GelMA hydrogel composite hernia patch, comprising the steps of:

[0012] Step S1, preparing a type IV collagen solution and injecting it into a microneedle mold to obtain a microneedle array layer by freeze-drying;

[0013] Step S2, preparing a GelMA prepolymer solution, adding HRP and H2O2 to form an enzyme crosslinking system;

[0014] Step S3, placing the microneedle mold in a flat mold and pouring the GelMA prepolymer solution to cover the roots of the microneedle heads;

[0015] Step S4, controlling the temperature and reaction time to perform enzyme crosslinking to form the microneedle / GelMA hydrogel composite hernia patch;

[0016] Step S5, demolding, drying and sterile packaging.

[0017] Preferably, in the step S1, the mass concentration of the type IV collagen solution is 10%-15% w / v.

[0018] Preferably, in the step S1, the type IV collagen solution is vacuum degassed and then freeze-dried, and the freeze-drying conditions are -40℃ to -20℃, a vacuum degree of 10-30Pa, and a freeze-drying time of 12-24 hours.

[0019] Preferably, in the step S2, the mass concentration of the GelMA prepolymer solution is 8%-12% w / v, the concentration of the HRP is 0.1-0.3U / mL, and the concentration of the H2O2 is 0.01-0.05% v / v.

[0020] Preferably, in the step S2, the temperature of the enzyme crosslinking reaction is controlled at 25℃-37℃, and the time is 10-60 minutes.

[0021] Preferably, in the step S2, a mixed solution of 2% carboxymethyl cellulose (CMC) and 2% hyaluronic acid (HA) in a ratio of 1:1 is sprayed on the tissue contact surface of the GelMA hydrogel of the microneedle / GelMA hydrogel composite hernia patch, and an anti-adhesion layer is formed after drying.

[0022] Compared with the prior art, the present application has the following beneficial effects:

[0023] In the present application, type IV collagen can self-assemble to form a basement membrane-like three-dimensional network, which is highly matched with the tissue structure of the peritoneum, significantly improving the tissue integration, wet stability and low immune reactivity of the hernia repair site. The type IV collagen protein gives the microneedle array layer good biocompatibility and degradability, and can naturally fuse with the tissue collagen fibers; the GelMA hydrogel provides flexible support and wet adhesion, and realizes stable interfacial bonding through enzyme crosslinking. After the patch is attached to the hernia defect, the microneedle array layer can be partially inserted into the tissue surface layer under the action of slight external force during the attachment process, and a distributed mechanical anchor is formed through the synergistic effect of multiple needles, so that the stable positioning of the patch is realized without the need for suturing or stapling. The GelMA hydrogel maintains adhesion and anti-adhesion properties in a body fluid environment, promoting tissue repair and regeneration.

[0024] The present application combines the tissue anchoring properties of the microneedle array layer and the adhesion and anti-adhesion functions of the GelMA hydrogel, achieving a comprehensive balance of mechanical fixation, local anti-inflammatory and antibacterial properties, degradability and biological fusion. Compared with traditional hernia repair materials, the patch described in the present application can significantly reduce the risk of postoperative infection and adhesion, and does not require suture or staple fixation, has the advantages of small trauma, fast healing, good compatibility, etc., and has broad clinical application prospects and industrialization value. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a flow chart of a preparation method of a microneedle / GelMA hydrogel composite hernia patch according to the present application;

[0026] Figure 2 is a white light imaging graph after the type IV collagen microneedle array is punctured on the pig skin tissue, used to verify the ability of the microneedle to penetrate the tissue surface layer, scale = 800 μm;

[0027] Figure 3 is a fluorescence imaging graph corresponding to the puncture area, used to further verify the insertion depth and distribution of the microneedle in the tissue, scale = 200 μm;

[0028] Figure 4 is a scanning electron microscope graph of the type IV collagen microneedle, showing the needle tip morphology and structural integrity, scale = 100 μm;

[0029] Figure 5 is an overall morphology graph of the type IV collagen microneedle array under a super-depth microscope, used to characterize the molding state, needle body height consistency and axial structure stability of the microneedle under actual size scale, scale = 300 μm;

[0030] Figure 6 is a curve graph of the adhesion strength in the comparative example of the present application. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0032] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative positional relationship, movement condition, etc. between components in a certain posture (as shown in the drawings), and if the certain posture changes, the directional indications also change accordingly.

[0033] In addition, if the embodiments of the present application involve descriptions such as “first”, “second”, etc., the descriptions of “first”, “second”, etc. are only for description purposes, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by “first” and “second” can explicitly or implicitly include at least one of the features. In addition, the meaning of “and / or” appearing throughout the text includes three parallel solutions. Taking “A and / or B” as an example, it includes A solution, or B solution, or A and B solutions. In addition, the technical solutions of each embodiment can be combined with each other, but it must be based on the fact that a person of ordinary skill in the art can realize it. When the combination of technical solutions contradicts each other or cannot be realized, it should be considered that the combination of technical solutions does not exist and is not within the protection scope of the present application.

[0034] The microneedle / GelMA hydrogel composite hernia patch in the embodiment comprises a microneedle array layer and a GelMA hydrogel, the microneedle array layer is composed of IV collagen which is shaped by freeze-drying, and the front surface of the microneedle array layer has a plurality of microneedle needles; the GelMA hydrogel is formed by enzymatic cross-linking solidification of HRP / H2O2 system, and the GelMA hydrogel covers and adheres to the root of the microneedle needle, wherein the IV collagen microneedle array layer forms a microneedle morphology with a clear needle tip structure and axial strength after freeze-drying shaping, and the microneedle can be inserted into the soft tissue surface layer along the axial direction when pressed, so as to realize the initial mechanical fixation of the patch without damaging the deep tissue. According to the actual situation, the microneedle needle length of the microneedle array layer can be selected as 400 μm, 600 μm, 800 μm, and the arrangement density is 10×10, 5×15, 20×20 needles / cm 2The thickness of the GelMA hydrogel is 0.8 mm, 1 mm, 1.5 mm. The covalent bonding between the microneedle array layer and the GelMA back plate is achieved by HRP-mediated tyrosine crosslinking to enhance the interface bonding strength.

[0035] Example 1: Preparation of a microneedle / GelMA hydrogel composite hernia patch (see preparation process in Figure 1 ).

[0036] 1. Preparation of GelMA prepolymer: 1.0 grams of gelatin methacrylate (GelMA) powder was weighed and dissolved in 10 milliliters of PBS solution at a ratio of 10% (w / v) under magnetic stirring at 37°C until completely dissolved. Then 0.3% (w / v) horseradish peroxidase (HRP) and 0.03% (v / v) hydrogen peroxide (H2O2) solution were added, and the mixture was thoroughly mixed for later use. This solution is used for subsequent hydrogel preparation and has good crosslinking and adhesion properties.

[0037] 2. Preparation of microneedle mold: a polydimethylsiloxane (PDMS) microneedle mold was prepared using laser etching technology. The mold has multiple conical needle cavities with a height of 600 microns and a base diameter of 150 microns, with a needle spacing of 400 microns. After cleaning with ethanol, the mold was dried in a vacuum drying oven for 2 hours to remove surface impurities and moisture.

[0038] 3. Preparation of microneedle array layer: 0.8 grams of type IV collagen powder was dissolved in 10 milliliters of pH 7.4 buffer to prepare a solution with a concentration of 12% (w / v) and thoroughly stirred to form a transparent solution. The resulting solution was injected into the microneedle mold and placed in a vacuum degassing instrument to remove air bubbles to ensure that the microneedle cavities were fully filled. Then the mold was freeze-dried at -40°C for 18 hours to obtain a collagen microneedle array with complete structure. The resulting microneedles are arranged in a neat and sharp manner, with good morphology stability and tissue penetration ability.

[0039] 4. GelMA hydrogel formation and compounding: the prepared microneedle mold was placed in a horizontal mold tray, and the pre-prepared GelMA prepolymer solution was slowly poured to cover the root of the microneedle head by about 1 millimeter. Then the reaction was carried out at 25°C for 30 minutes to form a GelMA hydrogel with elasticity and adhesion through HRP / H2O2 system enzymatic crosslinking. During the enzymatic crosslinking process, the tyrosine groups between collagen and GelMA can form covalent bonding, thereby enhancing the interface bonding force of the two-layer structure and forming a stable patch.

[0040] 5. Construction of anti-adhesion layer: On the tissue contact surface of the GelMA hydrogel, spray an anti-adhesion solution (concentration of each 2% w / v) formed by carboxymethyl cellulose (CMC) and hyaluronic acid (HA) in a mass ratio of 1:1, and dry after standing for 2 hours to form a dense and smooth anti-adhesion film layer.

[0041] 6. Demolding and drying: The patch after crosslinking and curing is slowly peeled off from the mold and placed in a 30°C vacuum drying oven for drying for 8 hours until the water content of the sample is less than 5%. The obtained patch is a translucent film with a thickness of about 1.2 millimeters, and the microneedle array is regular and has no collapse.

[0042] 7. Performance test:

[0043] (1) Mechanical property test: The tensile strength of the patch is measured by an electronic tensile tester, the maximum stress is 0.72±0.06 MPa, and the elongation at break is 43±4%.

[0044] (2) Tissue penetration performance test: The average penetration depth of the microneedle is 480-520 μm, and the insertion force is 0.25 N / needle on the pig skin tissue.

[0045] (3) Wet adhesion test: The adhesion strength between the back plate and the tissue is 28-32 kPa after soaking in PBS, which can stably maintain the adhesion for more than 48 hours.

[0046] (4) Degradation performance test: After soaking in PBS for 14 days, the residual mass of the patch is 34% of the initial mass, indicating that it has good degradability.

[0047] 8. Microneedle puncture and tissue fixation verification: To verify the integrity of the microneedle structure of the microneedle patch of the present application and its puncture and initial fixation ability to the tissue, the morphology and puncture performance of the prepared microneedle array are evaluated. First, the microneedle is observed by scanning electron microscopy and super-depth microscopy ( Figure 4 , Figure 5 ), and the results show that the microneedle tip morphology is clear, the arrangement is regular, the needle body structure is complete, and it has good molding consistency and mechanical stability.

[0048] Further, the in-vitro pig skin is selected as the simulated tissue, the microneedle patch is attached to the surface of the pig skin and light pressure is applied, and the microneedle can quickly penetrate into the tissue surface. The white light image and fluorescence imaging results of the pig skin after puncture show that ( Figure 2 , Figure 3 ), the microneedle forms uniform and clear puncture marks on the tissue surface, and there is no obvious needle body bending or falling phenomenon, indicating that the microneedle can effectively penetrate into the tissue and achieve stable initial mechanical fixation, providing a reliable structural basis for subsequent patch attachment and tissue repair.

[0049] 9. Animal experiment verification: select SD rats with a body weight of about 250 grams, under anesthesia, remove a 1cm x 1cm defect area on the abdominal wall, and attach the prepared microneedle wound patch hernia patch. The microneedle can quickly insert the tissue surface and be stably fixed, and the GelMA backboard forms a wet adhesion with the tissue surface. After 14 days of observation, the repaired part heals well, and there is no obvious inflammatory reaction or abscess formation. Compared with the ordinary GelMA patch group, the tissue adhesion score of the patch group of the present application is significantly reduced (P<0.05), the tissue repair is complete and the angiogenesis is rich.

[0050] In this embodiment, type IV collagen, as a basement membrane specific structural protein, has a unique three-dimensional network structure and α chain crosslinking mode. This structure makes it have more excellent stability and cell recognition characteristics in a wet tissue environment, can form molecular-level integration with the host tissue basement layer, thereby improving the quality of tissue fusion and repair.

[0051] Example 2: Preparation of a microneedle / GelMA hydrogel composite hernia patch (the preparation process is shown in Figure 1 ).

[0052] The rest is the same as example 1, except that the mass concentration of the type IV collagen solution is 10%. The freeze-drying conditions are -20℃, vacuum degree 10Pa, and freeze-drying time 12 hours.

[0053] The mass concentration of the GelMA prepolymer solution is 8% w / v, the concentration of HRP is 0.1U / mL, and the concentration of H2O2 is 0.01% v / v. The temperature of the enzymatic crosslinking reaction is controlled at 30℃, and the time is 10 minutes.

[0054] Example 3: Preparation of a microneedle / GelMA hydrogel composite hernia patch (the preparation process is shown in Figure 1 ).

[0055] The rest is the same as example 1, except that the mass concentration of the type IV collagen solution is 15% w / v. The freeze-drying conditions are -30℃, vacuum degree 30Pa, and freeze-drying time 24 hours.

[0056] The mass concentration of the GelMA prepolymer solution is 12% w / v, the concentration of HRP is 0.2U / mL, and the concentration of H2O2 is 0.05% v / v. The temperature of the enzymatic crosslinking reaction is controlled at 37℃, and the time is 60 minutes.

[0057] Comparative example 1:

[0058] To fully verify the long-term fixation stability of the patch in a wet state environment and the protection ability of the loaded drug, and to prove its sustained advantage compared to other microneedle systems, a 28-day comparative experiment was conducted.

[0059] 1. Sample and model drug preparation:

[0060] Experimental group: patch prepared in Example 1.

[0061] Control group A (structure control group): pure GelMA hydrogel patch without microneedle structure

[0062] Control group B (chemically cross-linked microneedle control group): chemically cross-linked silk fibroin microneedle patch prepared by mixing maleic anhydride modified silk fibroin (mass concentration 20% w / v) with stabilizer trehalose (mass concentration 5% w / v), using dithiothreitol (DTT) as a cross-linking agent, pouring and drying with a PDMS mold.

[0063] All groups were loaded with the same dose of model drugs, levofloxacin hydrochloride (antibacterial drug) and basic fibroblast growth factor (bFGF).

[0064] 2. Experimental method:

[0065] Fixation stability test: the sample was attached to the wet isolated porcine peritoneal tissue, immersed in PBS at 37°C, and placed on a horizontal shaker (50 rpm) for continuous shaking. The adhesion strength retention rate was determined at the preset time points (1st, 7th, 14th, 21st, 28th day).

[0066] Drug stability test (accelerated experiment): after sealing the sample loaded with bFGF, it was placed in a 40°C oven for accelerated stability test. After 28 days, the biological activity retention rate of bFGF was determined by ELISA kit and CCK-8 cell proliferation method.

[0067] 3. Experimental results:

[0068] 3.1 Wet state fixation stability: the experimental group patch showed excellent stability throughout the 28-day test period, with adhesion strength retention rate still maintaining above 80% at the end. The control group A (pure GelMA back plate) without microneedle structure showed rapid decay and basically lost its adhesion performance within a week after attachment. The control group B (chemically cross-linked silk fibroin microneedle) showed some fixation ability, but its adhesion strength decreased significantly over time, with a retention rate of less than 50% at the 28th day, and the overall stability was significantly lower than that of the experimental group. The adhesion performance change trend of each group is shown in Figure 6 .

[0069] 3.2 Drug activity retention rate: After 40℃, 28-day accelerated stability test, the biological activity retention rate of bFGF in the experimental group was (85.5±2.8)%. In contrast, the activity retention rate of bFGF in the control group B (chemical cross-linking microneedle control group) was only (68.2±4.5)%, showing a significant difference.

[0070] 4. Experimental conclusion:

[0071] Through the above comparative experiments, it can be seen that the microneedle composite patch of the application has better comprehensive performance in long-term wet state fixation performance and drug activity protection. It can maintain stable tissue fixation state in wet environment, and has better protection effect on bioactive drugs under long-term storage conditions.

[0072] In contrast, the silk fibroin microneedle patch prepared by chemical cross-linking has certain limitations in long-term fixation stability and drug activity retention.

[0073] The patch of the application shows excellent tissue integration and anti-adhesion performance in animal experiments. The patch can provide mechanical support and stable attachment in the early postoperative period, promote tissue regeneration, and gradually degrade and absorb during the healing process, without the need for secondary surgery to remove it. The overall structure is soft, comfortable and has no obvious foreign body reaction, significantly improving the repair effect and postoperative comfort.

[0074] Comparative Example 2:

[0075] In order to fully verify the anti-adhesion properties and structural integrity of the patch of the application in complex wet environment, and prove its comprehensive advantages compared to single functional materials, the following in vitro simulation experiments are compared and studied.

[0076] 1. Sample preparation:

[0077] Experimental group: The patch prepared in Example 1.

[0078] Control group D (simple microneedle control group): The same type IV collagen solution and PDMS mold as in Example 1 were used to prepare a pure type IV collagen microneedle array by freeze-drying molding. This sample does not have a GelMA hydrogel backboard and an anti-adhesion coating.

[0079] Control group E (commercial adhesive film control group): A commercially available medical tissue sealing adhesive film (its main components are gelatin-resorcinol-formaldehyde system) was selected and covered on an inert film substrate of the same size.

[0080] 2. Experimental method:

[0081] In vitro anti-cell adhesion test: Each group of samples (experimental group, control group D, control group E) was cut into a 1 cm diameter disc and placed at the bottom of a 24-well plate. The same number of mouse fibroblasts (L929) were inoculated on the surface of each group of samples, and cultured at 37°C, 5% CO2 for 48 hours. The relative proliferation activity of the cells on the sample surface was determined by the CCK-8 method, which indirectly represented the cell adhesion and growth. At the same time, Calcein-AM live cell staining was used to observe the adhesion morphology and density of the cells on the sample surface under a fluorescence microscope.

[0082] Wet-state interfacial bonding strength test: aimed to evaluate the bonding firmness between the microneedle array layer and the back plate in the composite structure. The front surface (microneedle surface) of the experimental group (microneedle + GelMA back plate) and control group D (pure microneedle array, temporarily adhered to the test base after wetting the back surface with a small amount of water) was fixed. Using a material testing machine, the back plate (or test base) was peeled off at a certain angle (such as 90°) and speed (such as 10 mm / min), and the maximum force value during peeling was recorded to calculate the interfacial bonding strength.

[0083] Swelling behavior and shape stability observation: each group of samples was immersed in a 37°C PBS solution. At the preset time points (1h, 4h, 24h), the samples were taken out, the surface moisture was absorbed with filter paper, and then weighed to calculate the swelling rate. At the same time, the sample morphology change was observed by optical microscope, especially the integrity of the microneedle structure.

[0084] 3. Experimental results:

[0085] 3.1 In vitro anti-cell adhesion ability:

[0086] Experimental group: the relative proliferation activity of cells on its anti-adhesion surface was only (6.5±1.3)%. Under the fluorescence microscope, only a small amount of scattered, round cells were seen, with almost no spreading, indicating that its surface can effectively resist cell adhesion. Control group D (simple microneedle): the relative proliferation activity of cells was as high as (88.2±5.1)%. Under the microscope, a large number of cells were tightly adhered to the surface and gaps of the microneedle, and showed good spreading morphology, indicating that the simple microneedle structure provided favorable adhesion sites for cells. Control group E (commercial adhesive film): the relative proliferation activity of cells was (52.7±4.8)%, which was significantly higher than that of the experimental group, indicating that its anti-cell adhesion ability was limited.

[0087] 3.2 Wet-state interfacial bonding strength: Experimental group: the interfacial bonding strength between the microneedle array layer and the GelMA hydrogel backing plate is (25.3±2.1) kPa. The peeling surface occurs within the GelMA layer rather than the interface between the two layers, proving that the two form a stable whole through enzymatic crosslinking. Control group D (pure microneedles): the "bonding" strength between its microneedle array and the temporarily wetted test base is extremely low and almost impossible to measure effectively (<2 kPa), and it separates under slight external force.

[0088] 3.3 Swelling behavior and shape stability: Experimental group: 24-hour swelling rate is (125±8)%. The overall structure remains intact after swelling, and the microneedle morphology is clear without collapse or dissolution. Control group D (pure microneedles): after encountering PBS, it quickly absorbs water and softens, and the microneedle structure deforms and collapses severely within 4 hours, making effective testing impossible. Control group E (commercial adhesive film): the 24-hour swelling rate is as high as (350±25)%, and the loose structure of the adhesive film leads to a significant decrease in mechanical strength.

[0089] 4. Experimental conclusion:

[0090] This embodiment fully proves the unique advantages of the patch of the present application through a series of in vitro experiments from the three dimensions of anti-cell adhesion, structural integrity, and wet-state stability:

[0091] In terms of anti-adhesion performance, the anti-adhesion surface of the patch of the present application can extremely effectively inhibit cell adhesion and growth, and its effect is much better than that of pure microneedle structure which easily causes cell adhesion and that of commercial adhesive film which has limited anti-adhesion ability.

[0092] In terms of structural synergy, the IV type collagen microneedle array and the GelMA hydrogel backing plate in the present application form a composite structure with a firm interface and integrated performance through enzymatic crosslinking, and its interfacial bonding strength is far superior to that of temporary physical adhesion, which is the basis for realizing long-term reliable fixation.

[0093] In terms of wet-state stability, the composite structure of the present application exhibits moderate swelling rate and excellent shape retention ability, overcoming the defects of pure collagen microneedles which quickly soften and collapse when encountering water, and commercial adhesive films which over-swelling leads to performance decline.

[0094] In summary, the present application successfully integrates excellent anti-adhesion characteristics, stable structural integrity, and good wet-state stability through the systematic design of microneedle anchoring, gel backing support, and anti-adhesion coating, which is indispensable. The comprehensive performance is beyond the reach of any single component or simple stacking of prior art.

[0095] Finally, it should be noted that the above only describes the preferred embodiments of the present application and is not intended to limit the present application. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art will appreciate that the technical solutions described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalent ones. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A microneedle / GelMA hydrogel composite hernia patch, characterized in that, It includes a microneedle array layer and a GelMA hydrogel. The microneedle array layer is composed of type IV collagen that has been freeze-dried and fixed. The front side of the microneedle array layer has multiple microneedle tips. The GelMA hydrogel is formed by enzymatic cross-linking and curing in an HRP / H2O2 system. The GelMA hydrogel covers and adheres to the base of the microneedle tips.

2. The microneedle / GelMA hydrogel composite hernia patch according to claim 1, characterized in that, The microneedle array layer has a microneedle tip length of 400μm to 800μm and an arrangement density of 10×10 to 20×20 needles / cm. 2 .

3. The microneedle / GelMA hydrogel composite hernia patch according to claim 1, characterized in that, The thickness of the GelMA hydrogel is 0.8 mm to 1.5 mm.

4. The microneedle / GelMA hydrogel composite hernia patch according to claim 1, characterized in that, The tissue contact surface of the GelMA hydrogel is provided with an anti-adhesion coating.

5. A method for preparing a microneedle / GelMA hydrogel composite hernia patch as described in any one of claims 1-4, characterized in that, include: Step S1: Prepare type IV collagen solution and inject it into a microneedle mold, then freeze-dry to obtain a microneedle array layer; Step S2: Prepare GelMA prepolymer solution, add HRP and H2O2 to form an enzyme cross-linking system; Step S3: Place the microneedle mold into the flat mold and pour in the GelMA prepolymer solution to cover the root of the microneedle tip; Step S4: Control the temperature and reaction time to perform enzymatic cross-linking to form the microneedle / GelMA hydrogel composite hernia patch; Step S5: Demolding, drying, and aseptic packaging.

6. The method for preparing the microneedle / GelMA hydrogel composite hernia patch according to claim 5, characterized in that, In step S1, the mass concentration of the type IV collagen solution is 10% to 15% w / v.

7. The method for preparing the microneedle / GelMA hydrogel composite hernia patch according to claim 5, characterized in that, In step S1, the type IV collagen solution is degassed under vacuum and then freeze-dried. The freeze-drying conditions are -40℃ to -20℃, vacuum degree of 10 to 30 Pa, and freeze-drying time of 12 to 24 hours.

8. The method for preparing the microneedle / GelMA hydrogel composite hernia patch according to claim 5, characterized in that, In step S2, the mass concentration of the GelMA prepolymer solution is 8%–12% w / v, the concentration of HRP is 0.1–0.3 U / mL, and the concentration of H2O2 is 0.01–0.05% v / v.

9. The method for preparing the microneedle / GelMA hydrogel composite hernia patch according to claim 5, characterized in that, In step S4, the temperature of the enzymatic cross-linking reaction is controlled at 25°C to 37°C, and the time is 10 to 60 minutes.

10. The method for preparing the microneedle / GelMA hydrogel composite hernia patch according to claim 5, characterized in that, In step S4, a 1:1 mixture of 2% carboxymethyl cellulose and 2% hyaluronic acid is sprayed onto the tissue contact surface of the GelMA hydrogel of the microneedle / GelMA hydrogel composite hernia patch, and after drying, an anti-adhesion layer is formed.

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