Dry double network hydrogel patch and preparation method and application thereof

Abstract

This invention relates to a dry dual-network hydrogel patch, comprising an interpenetrating dual-network adhesive layer composed of an N-hydroxysuccinimide-functionalized gelatin-polyethylene glycol diacrylate network and a polyacrylic acid network, and a polyurethane backing fixed to one side of the interpenetrating dual-network adhesive layer. Upon contact with a moist wound, the dry interpenetrating dual-network adhesive layer rapidly absorbs interfacial liquid, weakening the hydration barrier of the tissue surface. The synergistic effect of the initial non-covalent interactions mediated by the PAA network and the subsequent covalent anchoring provided by the gelatin-NHS-PEGDA network achieves rapid, stable, and durable tissue adhesion, can withstand high pressure loads, and can reliably close moist wounds. This invention also provides a method for preparing the dry dual-network hydrogel patch and an application of the dry dual-network hydrogel patch.

Description

Technical Field

[0001] This invention relates to the field of surgical supplies technology, specifically to a dry dual-network hydrogel patch, its preparation method, and its application. Background Technology

[0002] In recent years, minimally invasive surgery and digestive endoscopy techniques have been widely used in the diagnosis and treatment of abdominal organ diseases, demonstrating significant advantages in reducing surgical trauma, shortening hospital stays, and improving postoperative recovery. Nevertheless, intraoperative iatrogenic tissue damage remains difficult to completely avoid, especially complications such as gastrointestinal perforation and solid organ bleeding. Due to limited operating space, persistent tissue surface moisture, and dynamic organ movement, rapid and reliable closure and hemostasis are often difficult to achieve. Traditional suturing and mechanical closure are complex and may cause additional tissue damage; most existing tissue adhesives are easily interfered with by the hydration layer at high-moisture interfaces, making it difficult to simultaneously meet the requirements of immediate hemostasis, strong interfacial adhesion, and dynamic sealing. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to provide a dry dual-network hydrogel patch, its preparation method and application, to solve the technical problem that most existing tissue adhesives are easily interfered with by the hydration layer under high humidity interface, making it difficult to simultaneously meet the requirements of immediate hemostasis, strong interfacial adhesion and dynamic sealing.

[0004] This invention is achieved through the following technical solution: A dry dual-network hydrogel patch includes an interpenetrating dual-network adhesive layer composed of an N-hydroxysuccinimide ester-functionalized gelatin-polyethylene glycol diacrylate network and a polyacrylic acid network, and a polyurethane backing fixed to one side of the interpenetrating dual-network adhesive layer.

[0005] This invention also provides a method for preparing a dry dual-network hydrogel patch, which includes the following steps: S1. Preparation of primary network samples based on N-hydroxysuccinimide ester functionalized gelatin and polyethylene glycol diacrylate; S2. Add acrylic acid to the primary network sample prepared in step S1, mix thoroughly by vortexing, filter the resulting mixture through a 0.4μm sterile syringe filter to remove undissolved particles, transfer it to a mold with a lid to reduce moisture evaporation, and irradiate it with ultraviolet light. Acrylic acid polymerizes in situ to form a polyacrylic acid network, which interpenetrates with the primary network to obtain an interpenetrating double network structure sample. S3. Allow the obtained interpenetrating double network structure sample to stand and dry. S4. Curl polyurethane onto the back of the pre-formed hydrogel to form a backing.

[0006] Furthermore, a method for preparing primary network samples based on N-hydroxysuccinimide ester-functionalized gelatin and polyethylene glycol diacrylate: Gelatin, polyethylene glycol diacrylate solution, NHS and α-ketoglutaric acid were dissolved in deionized water and mixed under magnetic stirring until a uniform transparent solution was formed. The transparent solution was then irradiated with ultraviolet light for 30 minutes to initiate a photopolymerization reaction, thereby obtaining a primary network sample in a transparent pre-gel state based on N-hydroxysuccinimide ester functionalized gelatin and polyethylene glycol diacrylate.

[0007] Furthermore, the concentration of the gelatin in the deionized aqueous solution is 7%-8% w / v.

[0008] Furthermore, the concentration of the gelatin in the deionized aqueous solution is 7.5% w / v.

[0009] The present invention also provides an application of a dry dual-network hydrogel patch, wherein the above-mentioned dry dual-network hydrogel patch is adhered to the wound surface and pressed for 10 seconds.

[0010] Furthermore, the wound can be an intestinal wound, a liver wound, or a skin wound.

[0011] The beneficial effects of this invention are as follows: The dry-state dual-network hydrogel patch of this invention comprises an interpenetrating dual-network adhesive layer composed of an N-hydroxysuccinimide-functionalized gelatin-polyethylene glycol diacrylate network and a polyacrylic acid network, and a polyurethane backing fixed to one side of the interpenetrating dual-network adhesive layer. Upon contact with a moist wound, the dry-state interpenetrating dual-network adhesive layer rapidly absorbs interfacial fluid, weakening the hydration barrier of the tissue surface. The synergistic effect of the initial non-covalent interactions mediated by the PAA network and the subsequent covalent anchoring provided by the gelatin-NHS-PEGDA network achieves rapid, stable, and durable tissue adhesion, can withstand high pressure loads, and can reliably seal moist wounds.

[0012] The dry-state dual-network hydrogel patch described in this invention does not rely solely on high stiffness to gain mechanical advantages, but rather achieves a better balance between network strength and segment mobility, thereby endowing the material with better toughness and deformation adaptability. It exhibits good mechanical recovery and short-range cycle tolerance under large deformation conditions, maintaining structural stability in dynamic physiological environments such as continuous exudation, active bleeding, or dynamic tissue deformation, and possesses strong hemostatic ability.

[0013] The dry dual-network hydrogel patch of the present invention can be directly applied to the tissue surface without additional stimulation during use, which is simple to operate, and can be prepared into different sizes and shapes by means of molds to adapt to different types of tissue damage scenarios.

[0014] The dry dual-network hydrogel patch described in this invention is suitable not only for injuries to moist internal organs, but also for closing soft tissue wounds on the body surface.

[0015] The dry dual-network hydrogel patch described in this invention exhibits good biocompatibility, showing neither significant cytotoxicity nor inducing significant local adverse tissue reactions or visible systemic toxicity. This provides a safety basis for further research on its application in tissue closure, wound repair, and related biomedical fields.

[0016] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the layer structure of the dry dual-network hydrogel patch of the present invention; Figure 2 This is a schematic diagram of the UV crosslinking preparation of GAP dual-network hydrogel, showing the process of the system forming from a transparent pregel state to an interpenetrating polymer network structure; Figure 3 The images show the FT-IR analysis results of the interpenetrating double network structure sample, a and b. FT-IR analysis shows that at 1240 cm⁻¹... -1 NHS-related characteristic peaks appeared at 1544 cm⁻¹. -1 The appearance of an amide II band at [location] indicates that the NHS-activated ester participated in the reaction and formed a new amide bond; c. FT-IR analysis of the dried GAP patch showed that the characteristic O–H / N–H absorption band increased from 3417 cm⁻¹. -1 Blue shifted to 3448cm -1 This indicates a change in the interaction environment within the network; Figure 4 SEM image of primary gelatin-NHS-PEGDA network; Figure 5 SEM image of an interpenetrating dual-network structure; Figure 6 The mechanical properties of GAP hydrogels are characterized as follows: a) Schematic diagram of the initial state of the hydrogel and uniaxial tensile test; bd) Representative tensile stress-strain curves of GAP hydrogels with different gelatin concentrations (5%, 7.5%, and 10%, w / v), and the corresponding tensile strength and elongation at break; e) Stress-strain curves of the 7.5% gelatin group GAP hydrogel under continuous cyclic loading-unloading at 400% strain, used to evaluate its cyclic deformation tolerance and energy dissipation behavior. Figure 7 a) Changes in storage modulus (G′) and loss modulus (G′′) of GAP hydrogel with 5% gelatin concentration during frequency scanning; b) Changes in storage modulus (G′) and loss modulus (G′′) of GAP hydrogel with 7.5% gelatin concentration during frequency scanning; c) Changes in storage modulus (G′) and loss modulus (G′′) of GAP hydrogel with 10% gelatin concentration during frequency scanning. Figure 8 In the diagram, a, c, and e are schematic diagrams of the experimental setup used to evaluate the interfacial toughness (180° peel), normal adhesion strength, and lap shear strength of GAP patches, respectively; b, d, and f are quantitative results of the interfacial toughness, normal adhesion strength, and shear strength of GAP patches on the surfaces of pig skin, intestines, and liver, respectively. Figure 9 g. Schematic diagram of burst pressure testing device based on perforated tubing model; h. Comparison of burst pressure of GAP patch and clinical fibrin glue; Figure 10 In the image, a) is a representative image of GAP patch used in an isolated porcine intestinal wall injury model; b) is a representative image of GAP patch used in an isolated porcine liver surface linear injury model; c–g) are representative continuous images of isolated porcine intestinal injury sealing experiments; h–l) are images of the GAP patch application process and final coverage effect in the isolated porcine liver surface linear injury model. Figure 11 In the table, a) is a schematic diagram of the establishment of a linear liver injury model in rats; b) is a quantitative analysis diagram of total blood loss in each group; c) is a representative photograph of the blood accumulation on the liver surface and filter paper after treatment in the blank control group, fibrin glue group, and GAP patch group. Figure 12 In the image, a) shows the establishment of a full-thickness skin incision model on the rat's back and a schematic diagram of different treatment methods; b) shows representative photographs of wound closure on postoperative days 1, 4, 7, and 10 in different treatment groups; c) shows quantitative analysis of wound area on postoperative days 1, 4, 7, and 10 in different treatment groups; d) shows H&E staining images of the wound area on postoperative days 1, 4, 7, and 10 in different treatment groups; e) shows Masson's trichrome staining images of the wound area on postoperative days 7 and 10 in different treatment groups. Figure 13 H&E staining results of major organs (heart, liver, spleen, lung and kidney) after treatment of rat skin wounds with GAP patches; Figure 14In the images, a) live / dead staining images of NIH-3T3 cells cultured in GAP patch extract for 24, 48, and 72 hours; b) quantitative analysis of cell viability (CCK-8) of NIH-3T3 cells cultured in GAP patch extract for 24, 48, and 72 hours; c) schematic diagram of the rat subcutaneous implantation model; d) H&E staining images of the subcutaneous implantation areas in the GAP patch group and the fibrin glue group, showing mild local tissue reactions; e) H&E staining images of major organs (heart, liver, spleen, lung, and kidney) on postoperative day 10, showing no obvious systemic toxicity-related pathological changes.

[0018] In the figure: Interpenetrating double network adhesive layer-1; polyurethane backing-2. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0020] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0021] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0022] In the above description of the present invention, it should be noted that the terms "one side," "the other side," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of the invention is conventionally placed during use. These terms are used only for the convenience of describing the present invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0023] Furthermore, terms such as "identical" do not imply that components must be absolutely identical; minor differences are permissible. The term "perpendicular" simply means that the positional relationship between components is more perpendicular than "parallel," not that the structure must be perfectly perpendicular; a slight tilt is acceptable.

[0024] Please see Figure 1 The present invention provides a technical solution: a dry dual-network hydrogel patch, comprising an interpenetrating dual-network adhesive layer 1 composed of an N-hydroxysuccinimide (NHS) ester-functionalized gelatin-polyethylene glycol diacrylate (PEGDA) network and a polyacrylic acid (PAA) network, and a polyurethane backing 2 fixed to one side of the interpenetrating dual-network adhesive layer.

[0025] This invention also provides another technical solution: a method for preparing a dry dual-network hydrogel patch, used to prepare the above-mentioned dry dual-network hydrogel patch, comprising the following steps: S1. Prepare primary network samples based on N-hydroxysuccinimide ester functionalized gelatin (gelatin-NHS) and polyethylene glycol diacrylate (PEGDA); A method for preparing a primary network sample based on N-hydroxysuccinimide-functionalized gelatin (gelatin-NHS) and polyethylene glycol diacrylate (PEGDA): Gelatin, polyethylene glycol diacrylate solution, NHS, and α-ketoglutaric acid are dissolved in deionized water and mixed under magnetic stirring until a homogeneous and transparent solution is formed. The transparent solution is then irradiated with ultraviolet light for 30 minutes to initiate a photopolymerization reaction. The ultraviolet irradiation conditions are: UV, wavelength 284 nm, power 10 W, to obtain a transparent pre-gelled primary network sample based on N-hydroxysuccinimide-functionalized gelatin (gelatin-NHS) and polyethylene glycol diacrylate (PEGDA). The concentration of gelatin in the deionized aqueous solution is 7%-8% w / v, preferably 7.5% w / v. The concentration of PEGDA in the deionized aqueous solution is 1% w / v, and the concentration of α-ketoglutaric acid in the deionized aqueous solution is 0.5% w / v.

[0026] S2. Add acrylic acid (AA) to the primary network sample prepared in step S1, mix thoroughly by vortexing, filter the resulting mixture through a 0.4 μm sterile syringe filter to remove undissolved particles, transfer it to a covered mold to reduce moisture evaporation, and irradiate with ultraviolet light. The acrylic acid (AA) polymerizes in situ to form a polyacrylic acid (PAA) network, which interpenetrates with the primary network to obtain an interpenetrating double network structure sample, namely GAP hydrogel. Figure 2 ); Specifically, acrylic acid is added to the primary network sample based on N-hydroxysuccinimide ester functionalized gelatin (gelatin-NHS) and polyethylene glycol diacrylate (PEGDA) at a concentration of 30% w / v. Depending on the application, the mold cavity used in step S2 can be circular, square, or strip-shaped. The size of the mold cavity can be adaptively set according to actual usage requirements. The ultraviolet irradiation conditions are: UV, wavelength 284nm, power 10W, and irradiation time 30 minutes.

[0027] S3. Allow the obtained interpenetrating double network structure sample to stand and dry at an ambient temperature of 25 degrees Celsius and a humidity of 30%.

[0028] S4. Curl polyurethane (PU) onto the back of the pre-formed hydrogel to form a backing.

[0029] The present invention also provides another technical solution: the application of a dry dual-network hydrogel patch, wherein the above-mentioned dry dual-network hydrogel patch is adhered to the wound surface and pressed for 10 seconds. The wound surface can be an intestinal wound, a liver wound, or a skin wound.

[0030] Fourier Transform (FT-IR) characterization: The interpenetrating double network structure sample obtained in step S2 was characterized by Fourier transform spectroscopy. The Fourier transform infrared (FT-IR) spectroscopy results supported the formation of this interpenetrating double network structure. Compared with the sample without NHS, the sample containing NHS showed higher NHS concentration at 1240 cm⁻¹. -1 A characteristic absorption peak attributable to NHS-related structural vibrations appeared at 1544 cm⁻¹; simultaneously, at 1544 cm⁻¹... -1 The observation of a characteristic peak of amide II indicates that the NHS-activated ester participated in the reaction and formed new amide bonds, thereby introducing additional covalent connections into the network. Figure 3 a, b).

[0031] The O–H / N–H characteristic absorption band in the primary network sample based on N-hydroxysuccinimide-functionalized gelatin (gelatin-NHS) and polyethylene glycol diacrylate (PEGDA) extends from 3417 cm⁻¹. -1 Blue shifted to 3448cm -1 ( Figure 3(b) and (c) indicate that the hydrogen bonding environment in the system has changed, which is related to the enhanced carboxyl-related interactions and the rearrangement of internal network interactions after the introduction of PAA. The NHS active ester groups in the network further endow the material with the ability to form covalent anchors with amino groups on the tissue surface, thus contributing to rapid and stable bioadhesion. FT-IR results support the interpenetrating dual-network structure: the PAA network provides abundant carboxyl groups, which can form initial interfacial bonds with various substrate surfaces through non-covalent interactions such as hydrogen bonding and ionic interactions; the gelatin-NHS-PEGDA network provides reactive NHS active ester sites, which can further covalently react with amino groups on the tissue surface, thereby enhancing the stability and durability of interfacial adhesion. Simultaneously, the interpenetration and coupling of the two networks at the molecular scale helps with stress dispersion and energy dissipation, thus providing a structural basis for the material to balance adhesion and mechanical toughness.

[0032] Scanning electron microscopy (SEM) characterization: Scanning electron microscopy (SEM) characterization was performed on the primary network sample based on N-hydroxysuccinimide-functionalized gelatin (gelatin-NHS) and polyethylene glycol diacrylate (PEGDA) obtained in step S1, and the interpenetrating double network structure sample obtained in step S2. The results showed that the primary network sample based on N-hydroxysuccinimide-functionalized gelatin (gelatin-NHS) and polyethylene glycol diacrylate (PEGDA) exhibited a relatively loose and relatively uniform porous structure. Figure 4 ); In the interpenetrating double network structure sample formed after secondary UV crosslinking, a network structure with larger pore size and sparser distribution can be observed. Figure 5 ).

[0033] This further supports the formation of the interpenetrating double network structure. Notably, the dry state of the adhesive layer is beneficial for the storage and transportation of the material, and it can rapidly absorb and rehydrate after contact with the bleeding wound, thereby activating its interfacial adhesion properties.

[0034] In the description of subsequent experiments, the interpenetrating double network structure sample is referred to as GAP hydrogel, and the prepared dry double network hydrogel patch is referred to as GAP patch.

[0035] Mechanical property testing of GAP patches: Tensile mechanical properties of GAP hydrogels with gelatin concentrations of 5%, 7.5%, and 10% (w / v) were tested using a universal testing machine in a simulated body fluid (SBF) environment. Figure 6 a). The results showed that the gelatin concentration had a significant impact on the mechanical properties of GAP hydrogels.

[0036] The 5% gelatin group exhibited lower mechanical strength. Figure 6(b) Its tensile strength was 162.76±30.57 kPa, and its elongation at break was 387±69%. This indicates that at lower gelatin concentrations, the network structure formed by the system is relatively insufficient, making it difficult to effectively bear and transfer external stress. In contrast, when the gelatin concentration is increased to 7.5% ( Figure 6 c) GAP hydrogel exhibits the best overall mechanical properties, with its tensile strength increased to 373.70±7.50 kPa, while maintaining a high elongation at break (779±26%).

[0037] It is worth noting that the rheological frequency scanning results show that the elastic modulus of the 7.5% group is lower than that of the 10% group. Figure 7 ac), However, its tensile strength and ductility are superior to the latter. This result indicates that the 7.5% group does not simply rely on higher stiffness to gain mechanical advantages, but rather achieves a better balance between network strength and chain segment mobility, thus endowing the material with better toughness and deformation adaptability. When the gelatin concentration is further increased to 10% ( Figure 6 d) The tensile strength of the GAP hydrogel decreased to 324.80±43.50 kPa, and the elongation at break also decreased to 490±25%. This change suggests that while a higher gelatin content can improve the network rigidity of the GAP hydrogel, it also restricts the movement and rearrangement of polymer chains, thereby weakening the material's ductility during stretching and making it more susceptible to brittle failure. Overall, the 7.5% gelatin group exhibits a more balanced mechanical characteristic between strength and ductility. This combination of properties is more conducive to the patch adapting to periodic deformation after adhesion to the tissue surface and reduces the risk of GAP hydrogel cracking or interfacial failure caused by local stress concentration.

[0038] To further evaluate the mechanical stability of GAP hydrogels under dynamic loading conditions, cyclic tensile tests were performed on the 7.5% group of GAP hydrogel samples. Figure 6 e). The results showed that after five consecutive cycles of loading under 400% strain conditions, the stress-strain curves still maintained a high degree of overlap, and no obvious structural damage or rapid decay of mechanical properties was observed.

[0039] These results indicate that GAP hydrogels possess good mechanical recovery and short-range cycling tolerance under large deformation conditions, suggesting an effective energy dissipation mechanism within their network, which helps the material maintain structural stability in dynamic physiological environments.

[0040] GAP patch adhesion performance test: To systematically evaluate the adhesion ability of GAP patches to different moist tissue surfaces, isolated porcine skin, intestine, and liver tissues with different surface characteristics and mechanical properties were selected, and the interfacial toughness, normal adhesion strength, and shear strength of the GAP patches were tested respectively. Figure 8 a, c, e).

[0041] The results showed that the GAP patch rapidly absorbed water and hydrated upon contact with tissue, forming a stable adhesion interface within a short time. Due to differences in surface composition, liquid state, and cohesive strength among different tissues, the adhesion performance of the patch on various tissue surfaces exhibited a certain gradient. Interfacial toughness testing showed that the interfacial toughness (adhesion energy) of the GAP patch on the surfaces of porcine skin, intestine, and liver was 383.12 ± 75.20 Jm, respectively. -2 143.25±10.10Jm -2 and 94.23±8.72Jm -2 ( Figure 8 b). The normal adhesion strengths reached 106.38±12.80 kPa, 82.33±3.10 kPa, and 50.37±9.50 kPa, respectively. Figure 8 d). Further shear strength tests showed corresponding values ​​of 47.97±7.16 kPa, 32.22±2.87 kPa, and 16.83±0.29 kPa, respectively. Figure 8 f).

[0042] The above results demonstrate that GAP patches can achieve rapid and stable multimodal adhesion to different types of moist tissue surfaces. From a tissue perspective, GAP patches exhibited the highest interfacial toughness and adhesion strength on porcine skin, which is related to the high structural integrity and abundant reactive groups in skin tissue. For intestinal tissue continuously covered by fluid, GAP maintained high interfacial adhesion performance, indicating its good adaptability to wet interfaces. For the blood-rich and fragile liver surface, although the measured adhesion strength was relatively low, no significant interfacial deadhesion was observed during the test; the main manifestation was local tissue cohesion disruption, suggesting that the interfacial bonding strength between GAP and the liver surface reached or exceeded the local tissue cohesion strength.

[0043] Considering that intraoperative tissue incision, perforation, or injury is often accompanied by local fluid leakage and pressure load, the sealing ability of the GAP patch was further evaluated through burst pressure testing. Figure 9 g). Specifically, a GAP patch was placed over an opening with a diameter of approximately 2 mm, and its ultimate pressure resistance to liquid leakage was measured. The results showed that the burst pressure of the GAP patch reached 202.55 ± 13.69 mmHg, significantly higher than the 76.61 ± 9.89 mmHg of the fibrin glue group (g). Figure 9(h) indicates that it has strong sealing ability and can withstand high pressure load.

[0044] GAP patch sealing ability test in isolated porcine organ models: To evaluate the immediate sealing ability of GAP patches on the surface of moist organ injuries, an iatrogenic injury model of isolated porcine organs was established. Given that gastrointestinal perforation is a common and serious complication during gastrointestinal surgery, a linear full-thickness through-the-wall incision of approximately 1 cm was first prepared in isolated porcine intestine to simulate intestinal perforation. Under untreated conditions, physiological saline was infused into the sealed intestinal segment with progressively increasing pressure, resulting in continuous fluid leakage at the incision site. Subsequently, a GAP patch was applied to the moist wound (outer wall of the intestine) and gently pressed for approximately 10 seconds, followed by another water injection and pressure test. The results showed that after treatment with the GAP patch, leakage at the incision site was rapidly suppressed, indicating that the GAP patch can quickly establish a stable seal on the surface of the moist intestinal wall, thereby effectively preventing fluid leakage.

[0045] To further verify the applicability of GAP patches on different intestinal wall surfaces, a linear lesion of approximately 1 cm was also created on the inner wall of the intestinal tract. Figure 10 (a, cg). Experimental results showed that leakage disappeared rapidly after GAP patch treatment, indicating that it has good sealing ability on different intestinal wall tissue surfaces. Notably, even when the intestinal tract underwent significant radial expansion after fluid filling, no obvious slippage or material breakage was observed in the patch, indicating that it can maintain good interfacial stability under pressure and deformation conditions.

[0046] Furthermore, to investigate the applicability of GAP patches on the surface of solid organs, a linear lesion approximately 2 cm long was created on the surface of isolated porcine liver, and the GAP patch was applied to the moistened liver tissue surface with gentle pressure for 10 seconds. The results showed that the patch could form a tight adhesion to the liver surface. Figure 10 (b, h–l). Although this ex vivo model did not involve the bleeding challenge under real hemodynamic conditions, it exhibited good adhesion and surface retention on the surface of moist liver tissue. In summary, the GAP patch demonstrated good immediate sealing ability and adaptability to moist tissue surfaces in different types of ex vivo porcine organ injury models.

[0047] Hemostatic performance test of GAP patch: To evaluate the hemostatic ability of GAP patches under in vivo active bleeding conditions, a rat liver hemorrhage model was established. Figure 11 a) Specifically, linear lesions were created on the surface of rat livers, and weighing filter paper was placed beneath the liver beforehand. Bleeding was collected by weighing, and the amount of blood loss was calculated. Untreated wounds served as a negative control group. Given that fibrin glue has been widely used as a clinical reference for tissue sealing and hemostasis, it was used as a positive control group in this study.

[0048] The results of the blood loss analysis showed that ( Figure 11 (b) The blood loss in the GAP patch group was 158±40.5 mg, significantly lower than that in the fibrin glue group (621±168 mg) and the blank control group (1077±101 mg). The untreated group showed continuous and significant bleeding, while the fibrin glue group reduced blood loss to some extent, but its hemostatic effect was still significantly weaker than that in the GAP patch group. Figure 11 c).

[0049] The above results demonstrate that GAP patches can achieve more effective wound coverage and hemostasis control in a liver active bleeding model. The superior hemostatic performance of GAP patches is related to the synergistic effect of their rapid water absorption activation and stable interfacial adhesion. On the one hand, the dry patch can rapidly absorb interfacial fluid upon contact with the bleeding wound, thereby promoting direct contact between the material and the moist tissue surface; on the other hand, the stable adhesion formed on the tissue surface helps to quickly cover the wound and reduce continuous blood extravasation. These synergistic effects jointly promote the effective hemostasis of GAP patches in a dynamic bleeding environment.

[0050] Evaluation trial of the expanded application of GAP patches in full-thickness skin incision closure: After verifying the sealing and hemostatic properties of GAP patches in moist visceral tissues, a full-thickness skin incision model on the back of a rat was further used to evaluate its applicability in closing soft tissue wounds on the body surface, in order to examine the potential for expanding the application of this material in different tissue scenarios. A full-thickness skin incision model on the back of a male rat (incision length 2 cm) was established in the experiment. Figure 12 a), and set up an interrupted surgical suture group and a commercially available fibrin glue group as positive controls, while an untreated blank control group was set up to evaluate the natural healing process.

[0051] The results showed that GAP patches could achieve wound closure after covering the incision with light pressure for about 10 seconds, and maintained good interfacial adhesion and wound closure integrity even after surgery until dressing change, under conditions where there was no external bandaging and the animal was allowed to move freely. Figure 12 b). In contrast, fibrin glue is more prone to detachment in dynamic skin environments, leading to unstable wound closure; while sutures provide reliable fixation, they inevitably introduce pinhole damage and local stress concentration.

[0052] Macroscopic healing results showed that on the 7th day after surgery, the wound area in the GAP patch group was significantly smaller than that in the blank control group and the fibrin glue group. Figure 12c), indicating that GAP patches help promote early wound closure. H&E staining further showed that both the GAP patch group and the suture group exhibited only low to moderate inflammatory cell infiltration throughout the observation period, which largely subsided by day 10; in contrast, the blank control group and the fibrin glue group showed more pronounced inflammatory responses and tissue structural disorder, with the fibrin glue group showing more inflammatory cell infiltration in the incision area on day 7, suggesting a relatively stronger early inflammatory response. Figure 12 d). The above results indicate that GAP patches promote wound closure without causing abnormal or excessive local inflammatory responses.

[0053] Collagen deposition is an important indicator of skin wound repair and tissue remodeling. Masson staining results showed that, compared with the blank control group and the fibrin glue group, the GAP patch group and the suture group exhibited earlier collagen deposition on postoperative days 1 and 4, suggesting that it helps in early wound matrix remodeling. From postoperative day 7 to day 10, collagen deposition in the wounds of all groups gradually increased; by day 10, there was no significant difference in collagen deposition levels between the GAP patch group and the suture group. Figure 12 (e) indicates that the GAP patch did not hinder the later matrix remodeling process of the wound.

[0054] In addition, to assess the in vivo safety of GAP patches after application to skin wounds, histological analysis was performed on major organs (heart, liver, spleen, lung, and kidney). The results showed that no significant organ toxicity-related pathological changes were observed in either the GAP patch group or the control group. Figure 13 In summary, GAP patches also demonstrated rapid wound closure, mild local inflammatory response, and good tissue compatibility in full-thickness skin incision models, indicating that this material, in addition to being suitable for injuries to moist internal organs, also has the potential to be extended to the closure of soft tissue wounds on the body surface.

[0055] Biocompatibility testing of GAP patches: To systematically evaluate the biocompatibility of GAP patches, in vitro cell experiments and in vivo implantation experiments were conducted. In the in vitro experiments, mouse embryonic fibroblasts (NIH-3T3) were cultured in GAP patch extract and control culture medium, respectively, and live / dead staining and CCK-8 assays were performed after 24, 48, and 72 hours of culture. Figure 14 (a, b) The results showed that the cell survival in the experimental group was similar to that in the control group at each time point, and the cells were intact and spread well, indicating that the GAP patch extract did not show obvious cytotoxicity.

[0056] In in vivo experiments, GAP patches and commercially available tissue adhesive fibrin glue were implanted subcutaneously into the backs of SD rats. After 14 days, samples were collected, and H&E staining analysis was performed on the implanted skin and surrounding tissues. Figure 14(c, d) Histological results showed that the GAP patch group only induced a mild local inflammatory response, similar in degree to that in the fibrin glue group, and no obvious tissue necrosis or abnormal pathological proliferation was observed in either group. This result indicates that the GAP patch has good local tissue compatibility in vivo.

[0057] Furthermore, to further evaluate the systemic safety of GAP patches under subcutaneous implantation conditions, histological observation of major organs (heart, liver, spleen, lung, and kidney) revealed no significant pathological abnormalities in either the GAP patch group or the fibrin glue group. Figure 14 (e) indicates that the GAP patch did not cause significant systemic toxicity during the observation period. Combined in vitro and in vivo experimental results show that the GAP patch has good biocompatibility, exhibiting neither significant cytotoxicity nor inducing significant local adverse tissue reactions or visible systemic toxicity. These results provide a safety basis for further research on its application in tissue closure, wound repair, and related biomedical fields.

[0058] GAP patches can be directly applied to tissue surfaces without additional stimulation during use, and can be molded into different sizes and shapes to adapt to different types of tissue injuries. As a patch-type material, its application is relatively intuitive, which helps reduce the loss of liquid materials on complex wounds; at the same time, the dual-network structure gives it good mechanical toughness and deformation adaptability, thus providing a material basis for stable coverage of tissue surfaces, defect closure, and local reinforcement.

[0059] GAP patches exhibit consistent advantages in mechanical properties, tissue adhesion, damage sealing, and hemostasis. Material characterization shows that GAP patches possess good tensile properties and energy dissipation capacity, which are crucial for their adaptation to dynamic soft tissue deformation. Further adhesion tests demonstrate that GAP patches can form stable interfacial bonds on various moist tissue surfaces, including porcine skin, isolated intestines, and liver, exhibiting high interfacial toughness, normal adhesion strength, and shear adhesion strength. Ex vivo organ injury models further validated its sealing ability on complex tissue surfaces: whether resisting leakage challenges caused by luminal expansion in an intestinal perforation model or achieving rapid coverage in a liver surface injury model, GAP patches demonstrated good interfacial stability and immediate sealing ability. These results indicate that the material not only possesses strong initial adhesion but also maintains effective sealing under moist and stressed conditions. In in vivo functional validation, GAP patches significantly reduced blood loss in a rat liver active hemorrhage model, and their hemostatic effect was superior to fibrin glue and the blank control group. This result demonstrates that GAP patches can not only achieve wound closure under in vitro conditions but also exert effective local hemostasis under real blood flow conditions. Combining its material configuration and wet adhesion behavior, this performance stems from two synergistic effects: firstly, the patch can quickly establish a tight interface upon contact with a moist wound, thereby reducing continuous fluid exudation; secondly, the material itself possesses a certain degree of mechanical integrity, forming a relatively stable physical barrier on the wound surface.

[0060] In addition to its application in moist visceral tissues, the potential for further application of GAP patches was evaluated in a rat full-thickness skin incision model. Results showed that GAP patches enabled rapid wound closure and exhibited a smaller wound area and higher healing rate in the early postoperative period. Histological analysis further indicated that the GAP patch group performed similarly to the suture group in terms of inflammatory response control and collagen regeneration, and no abnormal local tissue reactions were observed. These results suggest that GAP patches, besides being suitable for closure and hemostasis of moist visceral tissues, also have the potential to be extended to the closure of soft tissue wounds on the body surface. Good biocompatibility is the foundation for the further transformation and application of tissue adhesive materials. In vitro cell experiments showed that the GAP patch extract did not exhibit significant cytotoxicity; subcutaneous implantation experiments showed that it only caused mild local tissue reactions, similar to the fibrin glue group; and histological observation of major organs also showed no significant systemic toxicity-related pathological changes. These results collectively demonstrate that GAP patches have good in vitro and in vivo biocompatibility, providing necessary safety support for their further application.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A dry state double network hydrogel patch, characterized by: It includes an interpenetrating double network adhesive layer composed of an N-hydroxysuccinimide ester functionalized gelatin-polyethylene glycol diacrylate network and a polyacrylic acid network, and a polyurethane backing fixed to one side of the interpenetrating double network adhesive layer.

2. A method of preparing a dry state double network hydrogel patch, characterized by, The preparation of the dry dual-network hydrogel patch according to claim 1 includes the following steps: S1. Preparation of primary network samples based on N-hydroxysuccinimide ester functionalized gelatin and polyethylene glycol diacrylate; S2. Add acrylic acid to the primary network sample prepared in step S1, mix thoroughly by vortexing, filter the resulting mixture through a 0.4μm sterile syringe filter to remove undissolved particles, transfer it to a mold with a lid to reduce moisture evaporation, and irradiate it with ultraviolet light. Acrylic acid polymerizes in situ to form a polyacrylic acid network, which interpenetrates with the primary network to obtain an interpenetrating double network structure sample. S3. Allow the obtained interpenetrating double network structure sample to stand and dry. S4. Curl polyurethane onto the back of the pre-formed hydrogel to form a backing.

3. The method for preparing the dry dual-network hydrogel patch according to claim 2, characterized in that, Method for preparing primary network samples based on N-hydroxysuccinimide ester-functionalized gelatin and polyethylene glycol diacrylate: Gelatin, polyethylene glycol diacrylate solution, NHS and α-ketoglutaric acid were dissolved in deionized water and mixed under magnetic stirring until a uniform transparent solution was formed. The transparent solution was then irradiated with ultraviolet light for 30 minutes to initiate a photopolymerization reaction, thereby obtaining a primary network sample in a transparent pre-gel state based on N-hydroxysuccinimide ester functionalized gelatin and polyethylene glycol diacrylate.

4. The method for preparing the dry dual-network hydrogel patch according to claim 3, characterized in that: The concentration of the gelatin in the deionized aqueous solution is 7%-8% w / v.

5. The method for preparing a dry dual-network hydrogel patch according to claim 4, characterized in that: The concentration of the gelatin in the deionized aqueous solution is 7.5% w / v.

6. An application of a dry dual-network hydrogel patch, characterized in that: The dry dual-network hydrogel patch according to any one of claims 1-5 is adhered to the wound surface and pressed for 10 seconds.

7. The application of the dry dual-network hydrogel patch according to claim 6, characterized in that: The wound can be an intestinal wound, a liver wound, or a skin wound.

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