Preparation method of photocuring methacrylated gelatin hydrogel dressing

Abstract

The invention belongs to the technical field of dressing preparation, and particularly relates to a preparation method of a photocuring methacrylated gelatin hydrogel dressing, which comprises the following steps: step 1, dissolving methacrylated gelatin in a phosphate buffer solution to prepare a methacrylated gelatin solution with the mass concentration of 5-15%; 2, adding a natural photoinitiator into the solution obtained in the step 1, and uniformly stirring and mixing; 3, adding the traditional Chinese medicine active ingredient powder, and stirring until the powder is uniformly dispersed to obtain a mixed solution; and 4, pouring the mixed solution into a mold, and curing and molding under the irradiation of visible light. Chlorophyll or riboflavin is used as a natural photoinitiator and is directly dispersed in a methacrylated gelatin solution in a physical blending mode, a curing light source enables chlorophyll to completely avoid a chemical initiator, meanwhile, the process is simplified into physical stirring to replace nanoparticle synthesis and modification, visible light reduces the risk of tissue burn, the production cost is reduced, and the method is suitable for industrial production. The method is suitable for primary medicine.

Description

Technical Field

[0001] This invention belongs to the field of dressing preparation technology, specifically relating to a method for preparing photocurable methacrylamide gelatin hydrogel dressings. Background Technology

[0002] Methacrylamide gelatin (GelMA) is a photosensitive biomaterial prepared by chemically modifying gelatin. It combines the biocompatibility of natural biomaterials with the controllability of synthetic materials and is widely used in tissue engineering, 3D bioprinting, drug delivery and other fields.

[0003] A search revealed that invention patent CN112891618B discloses an in-situ photocurable antibacterial bone defect repair gel and its preparation method. The gel is composed of methacrylamide copper sulfide nanoparticles and methacrylamide gelatin after photocrosslinking. This invention introduces modified CuSNPs into GelMA gel, which can then be photocured and shaped in situ to obtain a CuSNPs-GelMA composite hydrogel. Near-infrared light irradiation of this composite material activates the photothermal effect of CuSNPs in the CuSNPs-GelMA composite hydrogel, promoting the proliferation and osteogenic differentiation of mesenchymal stem cells in the periodontal defect area. The slowly released Cu2+ from the composite material further endows the bone defect repair scaffold system with sustained antibacterial activity, greatly preventing post-periodontal surgery infection. This composite material is reasonably easy to prepare, inexpensive, highly operable, biocompatible, and exhibits excellent osteogenic effects, broadening the indications for periodontal regeneration surgery and also applicable to the repair of other bone defects.

[0004] The aforementioned disclosed technology requires the synthesis of methacrylated copper sulfide nanoparticles and involves multiple chemical reactions, such as copper acetate sulfidation, methacrylic anhydride, and dialysis for 3 to 7 days. This makes the process complex and difficult to mass-produce, and it is only suitable for laboratory use and difficult to mass-produce. Summary of the Invention

[0005] To address the aforementioned problems in the prior art, this invention provides a method for preparing photocurable methacrylamide gelatin hydrogel dressings. This method aims to solve the technical problem that the synthesis process in the prior art requires the synthesis of methacrylamide copper sulfide nanoparticles, which involves multiple chemical reactions, resulting in complex processes and high difficulty in mass production. This method is only suitable for laboratory use and is difficult to mass-produce.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing a photocurable methacrylamide gelatin hydrogel dressing, comprising the following steps: Step 1: dissolving methacrylamide gelatin in phosphate buffer solution to prepare a methacrylamide gelatin solution with a mass concentration of 5% to 15%; Step 2: adding a natural photoinitiator to the solution obtained in Step 1 and stirring to mix evenly; Step 3: adding powdered active ingredients of traditional Chinese medicine and stirring until evenly dispersed to obtain a mixed solution; Step 4: pouring the mixed solution into a mold and curing it under visible light with a wavelength of 400 to 700 nm.

[0007] Furthermore, the natural photoinitiator is chlorophyll.

[0008] Furthermore, the amount of the natural photoinitiator added is 0.5% to 2% of the mass of the methacrylamide gelatin.

[0009] Furthermore, the active ingredients of the traditional Chinese medicine include at least one of total flavonoids from okra flower and borneol.

[0010] Furthermore, the amount of total flavonoids added from the okra flower is 0.1% to 3% of the mass of the methacrylamide gelatin.

[0011] Furthermore, the amount of borneol added is 0.1% to 2.5% of the mass of the methacrylamide gelatin.

[0012] Furthermore, in step three, water-soluble silk peptide powder is added, with the amount added being 0.5% to 1.5% of the mass of methacrylamide gelatin.

[0013] Furthermore, in step three, oxidized dextran is added in an amount of 0.1% to 1% of the mass of methacrylamide gelatin.

[0014] Furthermore, the intensity of the visible light irradiation is 30 to 100 mW / cm². 2 The curing time is 1 to 5 minutes.

[0015] Furthermore, the operating temperature for steps two and three is between 25 and 37 degrees Celsius.

[0016] Compared with the prior art, the beneficial effects of the present invention are:

[0017] 1. In this invention, chlorophyll or riboflavin is used as a natural photoinitiator and directly dispersed in a methacrylamide gelatin solution through physical blending. No chemical modification or dialysis is required throughout the process. The curing light source is extended to the 400 to 700 nm visible light range, allowing chlorophyll to completely avoid the cytotoxicity of chemical initiators such as LAP, greatly increasing cell survival rate. At the same time, the process is simplified to physical stirring instead of nanoparticle synthesis and modification, greatly shortening the preparation time. The visible light penetration depth at 480 nm reaches 2 to 3 mm, which is far higher than the 405 nm blue-violet light of the comparative patent, reducing the risk of tissue burns and thus greatly reducing production costs, making it suitable for primary healthcare. The safety of the light source supports in-situ curing of deep wounds in the body, such as abdominal ulcers.

[0018] 2. Existing technology relies solely on Cu 2+ Ionic antibacterial agents, while possessing limited functionality and lacking anti-inflammatory and analgesic capabilities, cannot meet the diverse needs of infected wounds such as burns and diabetic foot ulcers. In this invention, total flavonoids from Hibiscus syriacus (0.1 to 3 wt%) and borneol (0.1 to 2.5 wt%), along with other active ingredients from traditional Chinese medicine, are directly mixed into a methacrylamide gelatin solution in powder form. This eliminates the need for chemical grafting. By combining the anti-inflammatory and angiogenesis-promoting properties of flavonoids with the antibacterial, analgesic, and transdermal-promoting properties of borneol, a comprehensive antibacterial, anti-inflammatory, and repairing function is achieved. Low-temperature stirring prevents degradation of heat-sensitive components, significantly increasing the retention rate of active ingredients. Furthermore, it seamlessly integrates with the natural initiator system without increasing the complexity of the process.

[0019] 3. Existing technologies rely on 405nm high-energy blue-violet light, which has poor tissue penetration and is prone to photothermal damage. At the same time, it does not solve the problem of insufficient mechanical strength of hydrogels, such as easy breakage after transplantation. In this invention, a broadband visible light of 400 to 700nm is used for curing, and oxidized dextran is introduced to improve network toughness. Visible light devices are widely available, such as dental light curing lamps, making them convenient to use during surgery. Oxidized dextran enhances cross-linking through aldehyde-amino Schiff base reaction, greatly improving tensile modulus and matching the mechanical requirements of dynamic tissues. Water-soluble silk peptide powder is used as a co-initiator, which greatly reduces curing time. Attached Figure Description

[0020] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0021] Figure 1 This is a flowchart of the present invention. Detailed Implementation

[0022] 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. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Example 1:

[0024] Please see Figure 1 This embodiment provides the following technical solution: a method for preparing a photocurable methacrylamide gelatin hydrogel dressing, comprising the following steps: Step 1: dissolving methacrylamide gelatin in phosphate buffer to prepare a methacrylamide gelatin solution with a mass concentration of 5% to 15%; Step 2: adding a natural photoinitiator to the solution obtained in Step 1 and stirring to mix evenly; Step 3: adding powdered active ingredients of traditional Chinese medicine and stirring until evenly dispersed to obtain a mixed solution; Step 4: pouring the mixed solution into a mold and curing it under visible light with a wavelength of 400 to 700 nm.

[0025] Specifically, by using physical blending of natural photoinitiators and active ingredients from traditional Chinese medicine, and limiting visible light curing conditions (400-700nm), the chemical modification and dialysis steps are eliminated, shortening the preparation cycle to less than 24 hours and greatly simplifying the process. At the same time, the tissue penetration depth of the visible light source (400-700nm) reaches 2-3mm, avoiding thermal damage caused by high-energy blue-violet light (405nm) and improving the safety of clinical applications. Moreover, there are no complicated synthesis and purification steps throughout the process, the equipment requirements are low, and it is suitable for scale-up production on GMP standard production lines.

[0026] The natural photoinitiator is chlorophyll. The amount of natural photoinitiator added is 0.5% to 2% of the mass of methacrylamide gelatin.

[0027] Specifically, chlorophyll or riboflavin is used as the initiator; the residual toxicity of chemical initiators (such as LAP) is completely avoided, ensuring biosafety; cell survival rate is greatly improved; and the concentration of the initiator is limited to 0.5%-2% of the mass of methacrylamide gelatin; cross-linking is ensured to be completed within 1 to 5 minutes under visible light; the natural initiator is derived from plant extracts; it meets the green production standards for medical devices, and the raw materials are sustainable.

[0028] The active ingredients of the traditional Chinese medicine include at least one of the following: total flavonoids from Hibiscus syriacus flower and borneol. The amount of total flavonoids from Hibiscus syriacus flower added is 0.1% to 3% of the mass of methacrylamide gelatin. The amount of borneol added is 0.1% to 2.5% of the mass of methacrylamide gelatin.

[0029] Specifically, total flavonoids from Hibiscus syriacus flowers (0.1%-3%) provide anti-inflammatory and angiogenesis-promoting effects; borneol (0.1%-2.5%) achieves antibacterial, analgesic, and transdermal penetration enhancement effects; at the same time, the powder is directly and physically mixed in; the operating temperature is controlled between 25 and 37 degrees Celsius to avoid degradation of heat-sensitive components; the activity retention rate is greatly increased, ensuring activity stability; the two-component compound covers the comprehensive needs of infected wounds, such as burns and diabetic ulcers, for antibacterial, anti-inflammatory, and analgesic effects, thus expanding the indications.

[0030] Step three also involves adding water-soluble silk peptide powder, at a concentration of 0.5% to 1.5% of the mass of methacrylamide gelatin. Step three also involves adding oxidized dextran, at a concentration of 0.1% to 1% of the mass of methacrylamide gelatin.

[0031] Specifically, water-soluble silk peptide powder (0.5%-1.5% of the mass of methacrylamide gelatin) is used as a co-initiator; the curing time is shortened to less than 4 minutes, greatly increasing the crosslinking efficiency; oxidized dextran (0.1%-1% of the mass of methacrylamide gelatin) strengthens the network through Schiff base reaction, significantly improving the tensile modulus; meeting the mechanical strength requirements of dynamic tissues; oxidized dextran improves the swelling resistance of hydrogels; and the in vivo degradation cycle is extended to 14-21 days.

[0032] The intensity of visible light irradiation is 30 to 100 mW / cm². 2 The curing time is 1 to 5 minutes.

[0033] Specifically, light intensity 30-100mW / cm 2 With a duration of 1 to 5 minutes, it ensures the repeatability of clinical procedures; at the same time, it uses low-intensity visible light to replace ultraviolet and blue-violet light, reducing the risk of DNA damage; and it is compatible with existing medical equipment such as light curing lamps, reducing hospital procurement costs and improving the universality of the equipment.

[0034] The operating temperature for steps two and three is 25 to 37 degrees Celsius.

[0035] Specifically, it improves the low-temperature mixing environment to 25 to 37 degrees Celsius; prevents the thermal oxidation and deactivation of flavonoids; avoids high-temperature-induced pre-crosslinking of methacrylamide gelatin; ensures pouring fluidity and maintains solution stability; matches the operating room ambient temperature; supports immediate preparation and use during surgery; and greatly increases process compatibility.

[0036] Example 2:

[0037] Please see Figure 1 In this embodiment, the staff applied the method disclosed in this invention in the clinical practice of the burn department of a tertiary hospital;

[0038] Methacrylamide gelatin (GelMA, 50 kDa) was dissolved in phosphate buffer at 37°C to prepare a 12 wt% solution in 500 mL. Chlorophyll (0.8% by weight of GelMA) was added and stirred until dissolved. Next, total flavonoids from okra flowers (1.2% by weight of GelMA) and borneol powder (1.5% by weight of GelMA) were added, and the mixture was stirred at 200 rpm for 30 minutes in a constant temperature water bath at 37°C. Then, oxidized dextran (0.5% by weight of GelMA) and water-soluble silk peptide powder (1.0% by weight of GelMA) were added, and the mixture was stirred for another 15 minutes. Finally, after debridement, the mixed solution was poured onto the deep second-degree burn wound, covered with a 3 mm thick silicone mold, and cured with visible light (wavelength 480 nm, intensity 80 mW / cm²). 2 Irradiate for 120 seconds for in-situ crosslinking.

[0039] Oxidized dextran, through a Schiff base reaction, achieved a hydrogel tensile modulus of 35 kPa, 2.3 times higher than pure GelMA; flavonoids and borneol achieved a sustained release rate of 89% after 72 hours; the diameter of the inhibition zone against Pseudomonas aeruginosa was 15.2 mm; and the VAS score for wound pain decreased from 7.2 to 2.1; the chlorophyll initiator achieved a cell survival rate of 98.7%; the expression level of angiogenesis factor VEGF increased by 3.1 times; and the wound contraction rate was 92% after 21 days; the entire preparation process took 45 minutes, 160 times more efficient than nanoparticle synthesis; the visible light penetration depth was 2.8 mm without photothermal damage; and the cost per unit material was reduced by 67%.

[0040] The working principle of this invention is as follows: Chlorophyll, a natural photoinitiator, generates free radicals under irradiation with visible light at 400 to 700 nm, which triggers the cross-linking of double bonds in methacrylamide gelatin molecular chains to form a three-dimensional network structure. At the same time, total flavonoids from Hibiscus syriacus and borneol are embedded in the hydrogel through physical blending. The flavonoids exert anti-inflammatory and angiogenesis effects through sustained release at the wound site, while the borneol penetrates the gel network to achieve antibacterial and analgesic effects. The two work synergistically to overcome the functional limitations of single-ion antibacterial agents.

[0041] The aldehyde groups of oxidized dextran undergo a Schiff base reaction with the amino groups of gelatin to enhance network toughness, while water-soluble silk peptide powder accelerates free radical transfer and shortens the curing time to within 4 minutes. Ultimately, while eliminating the toxicity of chemical initiators and avoiding the complex process of nanoparticle synthesis and dialysis, it achieves a triple improvement in antibacterial, anti-inflammatory, and mechanical strength properties.

[0042] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a photocurable methacrylamide gelatin hydrogel dressing, characterized in that: Includes the following steps: Step 1: Dissolve the methacrylated gelatin in phosphate buffer to prepare a methacrylated gelatin solution with a mass concentration of 5% to 15%. Step 2: Add the natural photoinitiator to the solution obtained in Step 1 and stir to mix thoroughly; Step 3: Add the active ingredient powder of traditional Chinese medicine, stir until evenly dispersed, and obtain a mixed solution; Step 4: Pour the mixed solution into the mold and cure it under visible light with a wavelength of 400 to 700 nm.

2. The method for preparing photocurable methacrylamide gelatin hydrogel dressing according to claim 1, characterized in that: The natural photoinitiator is chlorophyll.

3. The method for preparing photocurable methacrylamide gelatin hydrogel dressing according to claim 2, characterized in that: The amount of the natural photoinitiator added is 0.5% to 2% of the mass of the methacrylamide gelatin.

4. The method for preparing photocurable methacrylamide gelatin hydrogel dressing according to claim 1, characterized in that: The active ingredients of the traditional Chinese medicine include at least one of the following: total flavonoids from Hibiscus syriacus and borneol.

5. The method for preparing photocurable methacrylamide gelatin hydrogel dressing according to claim 4, characterized in that: The amount of total flavonoids added from the okra flower is 0.1% to 3% of the mass of the methacrylamide gelatin.

6. The method for preparing photocurable methacrylamide gelatin hydrogel dressing according to claim 4, characterized in that: The amount of borneol added is 0.1% to 2.5% of the mass of methacrylamide gelatin.

7. The method for preparing photocurable methacrylamide gelatin hydrogel dressing according to claim 1, characterized in that: In step three, water-soluble silk peptide powder is also added, and the amount added is 0.5% to 1.5% of the mass of methacrylamide gelatin.

8. The method for preparing photocurable methacrylamide gelatin hydrogel dressing according to claim 1, characterized in that: In step three, oxidized dextran is also added, and the amount added is 0.1% to 1% of the mass of methacrylamide gelatin.

9. The method for preparing photocurable methacrylamide gelatin hydrogel dressing according to claim 1, characterized in that: The intensity of the visible light irradiation is 30 to 100 mW / cm². 2 The curing time is 1 to 5 minutes.

10. The method for preparing photocurable methacrylamide gelatin hydrogel dressing according to claim 1, characterized in that: The operating temperature for steps two and three is 25 to 37 degrees Celsius.

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