Hydrogel dressing, preparation method of hydrogel dressing and application of hydrogel dressing in plugging and repairing of through orificium fistulae

Abstract

The invention discloses a hydrogel dressing, a preparation method of the hydrogel dressing and application of the hydrogel dressing to plugging and repairing of a through orificium fistulae. The hydrogel dressing comprises a gelling component and a photoinitiator, and is formed by crosslinking under light irradiation, the mass ratio of the gelling component to the photoinitiator is (20-40): 1; the gel forming component comprises water, a cross-linking agent, an acrylamide monomer, polyvinyl alcohol, collagen, cellulose nanofibers and a zeolite imidazate skeleton structure material ZIF; the cross-linking agent is polysaccharide grafted with double bonds. The hydrogel dressing can also comprise a hydrolase and a catalase. The catalase is added to play a role in resisting oxidation, and the hydrolase is added to play a role in resisting fibrosis. Aiming at a series of problems of serious inflammation, serious fibrosis and the like of a penetrating fistula part, the material has certain mechanical toughness, viscosity, water-retaining property and drug delivery capability by adding reasonably matched characteristic components, and is used for rapid plugging, long-acting mechanical support and wound healing of the penetrating fistula.

Description

Technical Field

[0001] The invention relates to the technical field of gel dressings, and in particular to a hydrogel dressing, a preparation method thereof, and applications of the dressing in plugging and repairing through fistulas. Background Art

[0002] Head and neck cancer, oral cancer and other cancers will cause serious damage to the body after radiotherapy, and fistula repair treatment is more difficult at this time. Not only will there be problems with common fistulas due to the complex environment of the head and neck, but there will also be problems with skin fibrosis and oxidation after radiotherapy. What's worse, radiotherapy will reduce a person's immunity, making various complications more likely to occur.

[0003] Oral fistula is a common complication after the treatment of head and neck cancer and oral cancer. Once a penetrating fistula occurs, the situation is often extremely complicated and difficult to handle, which brings huge challenges to subsequent treatment. Especially penetrating orocutaneous fistula or oropharyngeal fistula, they usually appear in the extremely complex structure of the head and neck area. In this area, oral fistula may cause a series of serious consequences, such as refractory infection, which is difficult to be effectively controlled by conventional treatment methods; it may also cause carotid artery rupture. Once it occurs, the patient's life safety will be greatly threatened, and even serious life-threatening consequences may occur. These factors work together to make the healing process of oral fistula more difficult and complicated. Therefore, there is an urgent need to develop new biomaterials to solve this problem.

[0004] The development of fistula wound dressings has gone through traditional and modern stages. In the modern stage, driven by the theory of moist healing, wet dressings such as hydrogels and bioactive dressings containing growth factors, collagen, etc. have emerged. At present, research on the regeneration and repair of through fistulas is relatively extensive, but there is almost no research on the more difficult fistula repair after radiotherapy. In particular, there has been no report on biomaterials that integrate physical occlusion and biochemical repair, especially anti-fibrosis repair, to achieve regeneration and repair of through fistulas after radiotherapy. Summary of the invention

[0005] Due to the above-mentioned defects in the prior art, the present invention provides a hydrogel dressing, a preparation method thereof, and an application in the occlusion and repair of through fistulas, which has a series of good mechanical properties and drug sustained-release capabilities, and can be effectively used for the occlusion and repair of through fistulas (especially through fistulas after radiotherapy).

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] In a first aspect, the present invention provides a hydrogel dressing, comprising a gelling component and a photoinitiator, which is formed by cross-linking under light irradiation; the mass ratio of the gelling component to the photoinitiator is (20~40):1; the gelling component comprises water, a cross-linking agent, acrylamide (AAm) monomer, polyvinyl alcohol (PVA), collagen, cellulose nanofibers, and a zeolite imidazolate skeleton structure material ZIF; the cross-linking agent is a polysaccharide grafted with double bonds.

[0008] The hydrogel dressing is formed by light-induced crosslinking of double-bond grafted polysaccharide (CSMA) and AAm monomer into gel, adding PVA to enhance viscosity and water retention, adding collagen to promote tissue repair, and adding ZIF to enhance anti-inflammatory properties. The hydrogel dressing has certain viscosity, water retention, anti-inflammatory and sustained drug release capabilities, and has mechanical strength that matches sports tissue (elongation at break is higher than 600%), which can effectively isolate the infection of the moist environment inside the wound and provide mechanical support in the sports environment. It integrates physical blocking and biochemical repair, and provides new materials for dynamic and moist tissues, especially for the blocking and repair of through fistulas (such as oropharyngeal fistulas, esophageal fistulas, intestinal fistulas, anal fistulas, etc.) after treatment or radiotherapy.

[0009] Furthermore, the mass fraction of each component in the gelling component is:

[0010] Crosslinking agent 1%;

[0011] Acrylamide monomer and collagen 20%;

[0012] Polyvinyl alcohol 20%;

[0013] Cellulose nanofiber 1%;

[0014] ZIF 0.1%;

[0015] The balance is water.

[0016] Furthermore, the hydrogel dressing also includes hydrolase and catalase (CAT enzyme). The addition of CAT enzyme plays an antioxidant role, and the addition of hydrolase plays an anti-fibrosis role. By loading hydrolase, catalase, and anti-inflammatory and antioxidant substances such as ZIF, the wound repair microenvironment can be reshaped, intracellular oxidative stress can be reduced, cell growth can be promoted, and tissue regeneration and repair can be further accelerated; at the same time, the excess extracellular matrix can be decomposed to play an antioxidant role, which is used to support cell proliferation and promote tissue regeneration and repair; it has an anti-fibrosis function and is used for the treatment of normal function damage caused by fibrosis of tissues after radiotherapy.

[0017] Furthermore, the polysaccharide is any one or more combinations of gelatin, dextran, chitosan, chondroitin sulfate, and hyaluronic acid.

[0018] Furthermore, the hydrolase is bovine trypsin; the mass percentage of the hydrolase in the hydrogel dressing is 0.003%, and the concentration of the catalase in the hydrogel dressing is 0.99 mg / ml.

[0019] In a second aspect, the present invention provides a method for preparing a hydrogel dressing, which is used to prepare the hydrogel dressing as described above, comprising the following steps:

[0020] Step S1, mixing a gelling component with a photoinitiator to obtain a hydrogel precursor solution; the mass ratio of the gelling component to the photoinitiator is (20-40):1; the gelling component includes water, a crosslinking agent, acrylamide monomer, polyvinyl alcohol, collagen, cellulose nanofibers, and a zeolite imidazolate skeleton structure material ZIF; the crosslinking agent is a polysaccharide grafted with double bonds;

[0021] Step S2: Photoinduced polymerization to obtain a hydrogel dressing.

[0022] By adopting this technical solution, biological dressings for enhancing dynamic permeable fistula closure and promoting repair can be synthesized very simply and quickly.

[0023] Furthermore, in the step S1, trace amounts of hydrolase and catalase are added to the hydrogel precursor solution to prepare an enzyme-loaded hydrogel dressing.

[0024] Furthermore, in step S2, the hydrogel precursor solution is irradiated with ultraviolet light for more than 20 minutes to form a hydrogel dressing.

[0025] In a third aspect, the present invention provides a hydrogel dressing prepared by the above-mentioned preparation method.

[0026] In the last aspect, the present invention provides the use of the hydrogel dressing as described above as a dressing for plugging and repairing a through fistula. The through fistula includes oral oropharyngeal fistula, esophageal fistula, intestinal fistula, anal fistula, etc. In practical applications, the enzyme-loaded hydrogel dressing of the present invention is adhered to the fistula to achieve the plugging of the defect site, provide mechanical support for dynamic tissues, and effectively prevent bacterial infection in humid environments. At the same time, it can slowly release anti-fibrosis and antioxidant enzymes, thereby promoting cell proliferation and tissue regeneration and repair, and achieving the purpose of treatment and repair.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] (1) The hydrogel of the present invention can be used to treat a series of problems such as severe inflammation and severe fibrosis at the fistula site after radiotherapy. By reasonably matching characteristic components, the material can have certain mechanical toughness, viscosity, water retention and drug delivery capabilities, and can be used for the treatment of the disease. It can be used for rapid occlusion, long-term chemical support and wound healing of penetrating fistulas such as oral oropharyngeal fistulas after radiotherapy for oral cancer and head and neck cancer.

[0029] (2) The hydrogel dressing of the present invention can be rapidly formed under ultraviolet light irradiation. During the entire gelation process, only specific ingredients need to be added to a carefully formulated precursor solution. No complicated operation steps and additional processing procedures are required to achieve one-step forming. This process is not only simple and easy, greatly reducing the difficulty of operation, but also extremely fast, and can complete gelation in a short time, effectively improving production efficiency and providing strong technical support for related applications. The preparation process is simple and gentle, with good biocompatibility and strong tissue-specific adhesion, achieving strong adhesion and blocking of wound tissue, which can supplement or replace the role of sutures and avoid secondary damage to tissues. It integrates physical blocking and biochemical repair, and is not only suitable for rapid blocking of through fistulas, wound healing and long-term chemical support, but can also be used for anti-fibrosis needs after radiotherapy, improving patients' treatment tolerance, and has broad application prospects and promotion value.

[0030] (3) The hydrogel dressing of the present invention has suitable viscosity, mechanical strength, water retention and sustained drug release ability, which can effectively isolate the infection of the moist environment inside the wound, such as contamination by chyme, saliva and bacteria in the oral cavity, and provide mechanical support in the sports environment; at the same time, by loading hydrolases, catalases and anti-inflammatory and antioxidant substances such as ZIF, it can reshape the wound repair microenvironment, reduce intracellular oxidative stress, promote cell growth, and further accelerate tissue regeneration and repair. At the same time, it can decompose excess extracellular matrix to play an antioxidant role, integrating physical blocking and biochemical repair, and providing a new material for the treatment of through fistulas after radiotherapy (such as oropharyngeal fistulas, esophageal fistulas, intestinal fistulas, anal fistulas, etc.). BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The present invention and its features and advantages will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings, in which like reference numerals indicate like parts throughout the drawings.

[0032] Figure 1 It is a schematic diagram of the structure of the hydrogel dressing raw material and its product of the present invention;

[0033] Figure 2Mechanical properties of the hydrogel material prepared in Example 1: a, tensile curves of the hydrogel (GEL / E) loaded with hydrolase and CAT enzyme and the hydrogel (GEL) not loaded with enzyme; b, puncture curves of the hydrogel (GEL / E) loaded with hydrolase and CAT enzyme and the hydrogel (GEL) not loaded with enzyme;

[0034] Figure 3 Storage modulus (G') and loss modulus (G") curves of the repair layer hydrogel prepared in Example 2 under 37°C oscillation time scanning mode;

[0035] Figure 4 This is an image of the occlusion and sealing of the hydrogel dressing prepared in Example 3 in a New Zealand rabbit fistula model after radiotherapy;

[0036] Figure 5 These are representative photos of wounds in different treatment groups on days 0 to 28 in the New Zealand rabbit fistula model after radiotherapy in Example 4;

[0037] Figure 6 This is an H&E staining picture of the skin and mucosal side of the wound of the New Zealand white rabbit in Example 4 after 28 days of treatment. DETAILED DESCRIPTION

[0038] The structure of the present invention is further described below in conjunction with the accompanying drawings and specific embodiments, but is not intended to limit the present invention.

[0039] The reaction devices, compounds and solvents involved in the following embodiments and examples are all commercially available. The detection instruments and detection reagents involved in the following effect embodiments are all commercially available, the detection methods used are the prior art that can be retrieved, and the detection environment is a normal temperature environment.

[0040] See also Figure 1 The claims and specification of the present invention disclose a hydrogel dressing, comprising a gelling component and a photoinitiator, which is formed by cross-linking under light irradiation; the mass ratio of the gelling component to the photoinitiator is (20~40):1; the gelling component comprises water, a cross-linking agent, acrylamide (AAm) monomer, polyvinyl alcohol (PVA), collagen, cellulose nanofibers, and a zeolite imidazolate skeleton structure material ZIF; the cross-linking agent is a polysaccharide grafted with double bonds.

[0041] The hydrogel dressing is formed by light-induced cross-linking of double-bond grafted polysaccharide (CSMA) and AAm monomer into gel, the addition of PVA plays a role in enhancing viscosity and water retention, the addition of collagen plays a role in promoting tissue repair, and the addition of ZIF plays a role in enhancing anti-inflammatory properties.

[0042] The hydrogel dressing may also include hydrolases and catalase (CAT enzyme). The addition of CAT enzyme plays an antioxidant role, and the addition of hydrolases plays an anti-fibrosis role. By loading hydrolases, catalase, and anti-inflammatory and antioxidant substances such as ZIF, the wound repair microenvironment can be reshaped, intracellular oxidative stress can be reduced, cell growth can be promoted, and tissue regeneration and repair can be further accelerated; at the same time, excess extracellular matrix can be decomposed to play an antioxidant role, which is used to support cell proliferation and promote tissue regeneration and repair; it has an anti-fibrosis function and is used for the treatment of tissues that have been damaged in normal function due to fibrosis after radiotherapy.

[0043] The hydrogel dressing achieves certain mechanical toughness, viscosity, water retention and drug delivery capabilities by rationally matching characteristic ingredients, and is used for the treatment of the disease. It can be used for rapid occlusion of penetrating fistulas such as oral oropharyngeal fistulas after oral cancer and head and neck cancer radiotherapy, long-term chemical support and wound healing.

[0044] To further help understand the technical solution of the present invention, the technical solution and technical effects of the present invention are described in more detail below through several specific implementation examples.

[0045] Example 1 Preparation and performance testing of hydrogel (GEL) without enzyme loading

[0046] 1) Polysaccharide grafting double bonds: 14 g of chondroitin sulfate (CS) was dissolved in 100 mL of deionized water, stirred at room temperature for 0.5 h to form a uniform solution, 1M HCl was added dropwise to adjust the pH to 3.5, and then 4.5 mL of GMA (glycidyl methacrylate) was added to the above solution and reacted at 50 ° C for 2-3 h. After the reaction was completed, the solution was added to anhydrous ethanol while stirring to produce white flocs. After washing with anhydrous ethanol three times, it was dialyzed in deionized water for 3 days (MWCO molecular weight cutoff 8000-12000), and the dialyzate was freeze-dried. After complete drying, it was ground to obtain white powder CSMA (CS grafted with carbon-carbon double bonds).

[0047] 2) Preparation of hydrogel materials: 1% (w / w) CSMA, 20% (w / w) acrylamide (AAM) and collagen, 20% (w / w) polyvinyl alcohol (PVA), 1% (w / w) cellulose nanofiber, and 0.1% (w / w) ZIF were added to deionized water, mixed with a 40:1 photoinitiator (α-ketoglutaric acid) to obtain a precursor solution, and then placed under ultraviolet light (365 nm, 25 mW / cm 2) Irradiate with light for 30 minutes to polymerize into gel to obtain a gel material. The time for polymerizing gel is more than 20 minutes, which varies depending on the ratio and selection of the gel-forming components and the photoinitiator.

[0048] The mechanical properties of the prepared enzyme-free hydrogel material were tested by a tensile test machine. The tensile test measurement speed was 20 mm / min. The sample was in the shape of a round cake with a diameter of 1 cm and a thickness of 1 mm. The results are shown in Figure 2 As shown in a and 2b, the maximum elongation at break of the enzyme-free gel material is 650%, the puncture strength can reach more than 8 kPa, and it can withstand a puncture strain of more than 2700%, which can be applied to the movement and deformation of tissues at the site of through fistulas.

[0049] The enzyme-free hydrogel prepared by replacing chondroitin sulfate with any one or more combinations of gelatin, dextran, chitosan, and hyaluronic acid has similar properties to the GEL sample.

[0050] Example 2 Preparation and performance testing of enzyme-loaded hydrogel (GEL / E)

[0051] 1) Grafting double bonds onto polysaccharides: The steps are the same as step 1) in Example 1.

[0052] 2) Preparation of enzyme-loaded hydrogel material: The steps are similar to step 2) in Example 1, except that 0.003% (w / w) of hydrolase (such as bovine trypsin or other similar hydrolase) and 0.99 mg / ml of CAT enzyme are also added to the formula of the gel precursor solution.

[0053] The mechanical properties of enzyme-loaded hydrogels were tested by a tensile test machine. The tensile test measurement speed was 20 mm / min. The samples were in the shape of a round cake with a diameter of 1 cm and a thickness of 1 mm. The results are shown in Figure 2 As shown in a and 2b, the maximum elongation at break of the enzyme-loaded gel material is 700%, the puncture strength can reach more than 9 kPa, and it can withstand a puncture strain of more than 3500%, and can be applied to the movement and deformation of tissues at the site of through fistulas.

[0054] The enzyme-loaded hydrogel prepared by replacing chondroitin sulfate with any one or more combinations of gelatin, dextran, chitosan, and hyaluronic acid has similar properties to the GEL / E sample.

[0055] In order to determine the gelation time of the hydrogel adhesive, the storage modulus (G') and loss modulus (G") of the hydrogel were measured using a Thermo Haake rheometer at a frequency of 1 Hz and a shear stress of 1 Pa. The enzyme-loaded hydrogel precursor was first spread on a parallel plate (20 mm in diameter, 0.3 mm in gap) at 37 °C, and then UV irradiation was performed. A dynamic time scan was performed and then a dynamic frequency scan of 10 to 0.1 Hz was performed. The experimental results are shown in Figure 3 As shown in the figure, the storage modulus (G') and loss modulus (G") curves of the enzyme-loaded hydrogel in the frequency scanning mode at 37°C. Due to the chemical cross-linking of the hydrogel, the change of G' is independent of the frequency change of 10~0.1 Hz, and G' remains in a relatively stable state, showing good mechanical stability.

[0056] Example 3

[0057] In order to evaluate the sealing performance of the hydrogel dressing of the present invention on through fistulas after radiotherapy, we selected the oral oropharyngeal fistula, which has the characteristics of complex anatomical structure, variable physiological environment, repeated inflammatory stimulation and continuous tissue movement, and is extremely difficult to repair, as a model for animal experimental verification.

[0058] First, New Zealand rabbits were treated with X-ray radiotherapy (source-skin distance 100 cm, 35 / 40 Gy single local irradiation, which caused partial necrosis of the epidermis, hair loss, redness and swelling of the wound, inflammatory reaction, and ulceration). Then, a New Zealand rabbit oral fistula (POF) model was established. A 1.5×1.5 cm 2 Circular, penetrating wounds that penetrate the skin and oral mucosa (see Figure 4 Left figure), the hydrogel dressing prepared in step 3) of Example 2 is attached to the fistula (see Figure 4 Right), and achieves efficient adhesion through covalent coupling with amino groups on the tissue surface through hydrogen bonds in the polymer network.

[0059] Example 4

[0060] The repair-promoting effect of the hydrogel adhesive prepared in Example 1 and Example 2 was further evaluated using the New Zealand rabbit POF model, and a control group, a GEL group, and a GEL / E group were set up respectively. For the GEL / E group and the GEL group, the material obtained in step 2) of Example 2 and Example 1 was placed on the surface of the fistula, and the prepared hydrogel material could be completely attached to the wound defect surface without other operations, such as Figure 4 shown.

[0061] In contrast, the secondary tissue damage caused by the commonly used suture fixation in clinical practice was avoided, and samples were collected and tested every 3 days after surgery. Figure 5As shown, overall, the wound healing rate in the control group was slower than that in the wounds that had not been irradiated with x-rays. The wounds basically did not heal in the early stage after modeling, and the wound healing rate was significantly accelerated until the 18th day. On the 18th day, the enzyme-loaded hydrogel group (GEL / E group) and the pure hydrogel group (GEL group) achieved wound closure rates of 85.3% and 50.2%, respectively, which were significantly higher than the blank control group (9.8%). On the 28th day, the enzyme-loaded hydrogel group achieved complete healing (100.0%), but the gel group and the blank group did not completely heal on the 28th day (possibly due to x-ray irradiation). It is worth noting that, see Figure 6 (The ruler in the figure indicates the same length). The wound treated with the enzyme-loaded hydrogel dressing healed best on the 28th day (100%), and the skin and mucosa at the wound site achieved complete epithelialization, while the other two groups still had unhealed penetrating defects. However, the wound recovery of the non-enzyme-loaded hydrogel was better than that of the control group, indicating that the hydrogel dressing prepared by the present invention has an excellent repair-promoting effect on penetrating fistulas.

[0062] In summary, the hydrogel dressing and preparation method thereof provided by the present invention can well solve the technical problem of lack of materials for repairing fistulas in complex areas after radiotherapy, and can be very simply and quickly synthesized into a biological dressing for enhancing dynamic permeability fistula closure and promoting repair, and has high promotion and application value.

[0063] Those skilled in the art should understand that those skilled in the art can implement variations by combining the prior art and the above embodiments, which will not be described in detail here. Such variations do not affect the essential content of the present invention, and will not be described in detail here.

[0064] The above describes the preferred embodiments of the present invention. It should be understood that the present invention is not limited to the above-mentioned specific embodiments, and the devices and structures that are not described in detail should be understood to be implemented in a common manner in the art; any technician familiar with the art can use the above-disclosed methods and technical contents to make many possible changes and modifications to the technical solutions of the present invention without departing from the scope of the technical solutions of the present invention, or modify them into equivalent embodiments of equivalent changes, which does not affect the essential content of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention are still within the scope of protection of the technical solutions of the present invention.

Claims

1. A hydrogel dressing comprising a gelling component and a photoinitiator, which is cross-linked under light irradiation; characterized in that: The mass ratio of the gelling component to the photoinitiator is (20-40):1; the gelling component includes water, a crosslinking agent, acrylamide monomer, polyvinyl alcohol, collagen, cellulose nanofibers, and a zeolite imidazolate skeleton structure material ZIF; the crosslinking agent is a polysaccharide grafted with double bonds.

2. A hydrogel dressing according to claim 1, characterized in that: The mass fraction of each component in the gelling component is: Cross-linking agent 1%; Acrylamide monomer and collagen 20%; Polyvinyl alcohol 20%; Cellulose nanofiber 1%; ZIF 0.1%; The balance is water.

3. A hydrogel dressing according to claim 1 or 2, characterized in that: The hydrogel dressing also includes a hydrolase and a catalase.

4. A hydrogel dressing according to claim 1 or 2, characterized in that: The polysaccharide is any one or more combinations of gelatin, dextran, chitosan, chondroitin sulfate and hyaluronic acid.

5. A hydrogel dressing according to claim 3, characterized in that: The hydrolase is bovine trypsin; the mass percentage of the hydrolase in the hydrogel dressing is 0.003%, and the concentration of the catalase in the hydrogel dressing is 0.99 mg / ml.

6. A method for preparing a hydrogel dressing, characterized in that: The method for preparing the hydrogel dressing according to claims 1 to 5 comprises the following steps: Step S1, mixing a gelling component with a photoinitiator to obtain a hydrogel precursor solution; the mass ratio of the gelling component to the photoinitiator is (20-40):1; the gelling component includes water, a crosslinking agent, acrylamide monomer, polyvinyl alcohol, collagen, cellulose nanofibers, and a zeolite imidazolate skeleton structure material ZIF; the crosslinking agent is a polysaccharide grafted with double bonds; Step S2: Photoinduced polymerization to obtain a hydrogel dressing.

7. The method for preparing a hydrogel dressing according to claim 6, characterized in that: In the step S1, trace amounts of hydrolase and catalase are also added to the hydrogel precursor solution.

8. The method for preparing a hydrogel dressing according to claim 6 or 7, characterized in that: In the step S2, the hydrogel precursor solution is irradiated with ultraviolet light for more than 20 minutes to form a hydrogel dressing.

9. A hydrogel dressing, characterized in that: The method is described in any one of claims 6 to 8.

10. The use of a hydrogel dressing as a through fistula plugging and repair dressing, characterized in that: The hydrogel dressing is the hydrogel dressing according to any one of claims 1 to 5 and 9.

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