Self-adhesive, high-toughness, antibacterial wheat gluten protein film and preparation method thereof

Abstract

The application discloses a self-adhesive, high-toughness and antibacterial wheat gluten protein film and a preparation method thereof. The film has good skin adhesion, high tensile toughness and antibacterial performance, and is prepared through hydration kneading, hot-pressing forming, Cu2+ solution immersion coordination loading and glycerol-water solvent replacement treatment. Compared with a pure WG film, the tensile toughness of the film is improved by about 13.4 times, the tensile strength is improved by about 11.6 times, and the skin adhesion strength is improved by about 1.3 times, so that the organic unity of self-adhesion, high toughness, antibacterial property and dry resistance is realized, and the film is suitable for dynamic wound care of joint parts.

Description

Technical Field

[0001] This invention relates to the field of biomedical materials, specifically to a self-adhesive, high-toughness, antibacterial wheat gluten protein film and its preparation method. Background Technology

[0002] In the field of clinical trauma care, skin wounds at joint sites are subjected to continuous stretching, compression, and shearing dynamic mechanical environments, which places high demands on the performance of dressings. These demands include good self-adhesion to ensure that the dressing does not easily fall off during joint movement, high tensile strength and compliance to adapt to skin deformation, and long-lasting antibacterial properties to reduce the risk of infection.

[0003] Existing medical dressings, including foam dressings and hydrogel dressings, have seen improvements in some aspects, but often suffer from limited functionality. For example, some self-adhesive foam dressings offer advantages in ease of use, but are prone to curling or falling off during repeated flexion and extension; hydrogel dressings have good conformability, but their mechanical strength and intrinsic adhesion may be insufficient.

[0004] Wheat gluten protein (WG), a byproduct of wheat starch production, is widely available and rich in glutenin and gliadin. It has certain viscoelasticity and film-forming potential, and good biocompatibility, which is in line with the development trend of bio-based materials.

[0005] In the prior art, Chinese patent CN101780060A discloses a medical wheat protein membrane prepared by solution casting with the addition of plasticizers and cosolvents. It focuses on tensile strength and water absorption / retention properties, but does not address intrinsic self-adhesive design, provides data on elongation at break, or mention antibacterial function. Other related technologies, such as synthetic polymer hydrogels or structural joint dressings, also struggle to simultaneously meet the synergistic requirements of self-adhesion, high toughness, and antibacterial properties needed for joint applications.

[0006] There is still room for improvement in the intrinsic material adaptability, process simplicity, and multifunctional synergy of existing technologies in dynamic joint environments. Summary of the Invention

[0007] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0008] The technical problem to be solved by the present invention is to provide a self-adhesive, high-toughness, antibacterial wheat gluten protein film and its preparation method, so as to improve the fit, toughness and antibacterial properties of existing dressings in joint wound care.

[0009] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0010] A self-adhesive, high-toughness, antibacterial wheat gluten protein film is prepared by hydrating and kneading wheat gluten protein powder into dough, hot pressing it into shape, and then successively impregnating it with copper ion solution and treating it with glycerol-water solvent replacement.

[0011] Specific preparation methods include:

[0012] Preparation of WG dough: Wheat gluten protein powder with a protein content of 80±2% is mixed with deionized water at a ratio of 1:1 to 1:2. After kneading, the mixture is allowed to stand to obtain dough with a uniform network structure.

[0013] Hot pressing: Hot pressing at 60-100℃ for 3-10 minutes yields sheet-like WG films.

[0014] Copper ion loading: The WG film was immersed in a 1-1000 μmol / L CuSO4 solution for 1-4 h to achieve coordination binding of Cu²⁺ with the active groups of the protein.

[0015] Solvent replacement: Immerse the Cu²⁺-loaded membrane in a 25%-75% glycerol-water solution for 0.5-2 hours to obtain the target membrane.

[0016] Under preferred conditions, the material-to-liquid ratio is 1:1.5, kneading is performed 10-20 times, hot pressing is carried out at 80℃ for 5 min, CuSO4 concentration is 100 μmol / L, and glycerol volume fraction is 50%.

[0017] This invention achieves multifunctional unification through the synergistic effect of the following steps:

[0018] (1) The kneading process allows the wheat gluten protein molecular chains to fully stretch, expose the free thiol groups and convert them into disulfide bonds, forming self-crosslinking, and obtaining a dough with a macroscopically smooth, elastic and microscopically uniform three-dimensional network structure.

[0019] (2) The hot pressing process promotes dough flow and shaping at a suitable temperature, while further promoting the formation of disulfide bonds, increasing the network crosslinking density, and avoiding surface drying defects.

[0020] (3) Cu²⁺ impregnation loading enables the active groups such as amino and carboxyl groups on the WG molecular chain to form coordination bonds with Cu²⁺, stabilize the loading of copper ions, give the membrane long-lasting antibacterial properties, and enhance cohesion.

[0021] (4) The solvent replacement treatment of the glycerol-water binary solution is different from the premixed glycerol method. Glycerol molecules can fully enter the already formed protein network, reconstruct the hydrogen bond network, and improve the tensile toughness, skin adhesion strength and anti-drying properties of the membrane.

[0022] Compared with pure WG membrane, the membrane of this invention has an increased tensile toughness of about 13.4 times, an increased tensile strength of about 11.6 times, and an increased skin adhesion strength of about 1.3 times. It achieves an organic unity of self-adhesion, high toughness, antibacterial and anti-drying properties, making it suitable for dynamic wound care in joint areas. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0024] Figure 1 SEM images of cross-sections of WG dough at different kneading cycles according to the present invention;

[0025] Figure 2 These are macroscopic morphology images of the WG film at different hot-pressing temperatures according to the present invention;

[0026] Figure 3 The free thiol content at different hot-pressing temperatures according to the present invention;

[0027] Figure 4 The macroscopic morphology of the WG dough (liquid-to-material ratio 1:1.5, smooth and delicate appearance) and the SEM image of the cross-section of the WG dough (liquid-to-material ratio 1:1.5, uniform honeycomb structure) of the present invention are shown.

[0028] Figure 5 The macroscopic morphology of the WG dough of the present invention (material-liquid ratio 1:2, loose, unevenly shaped);

[0029] Figure 6 This is a cross-sectional SEM image of the WG dough of the present invention (material-liquid ratio 1:2, poor continuity of pores).

[0030] Figure 7 The macroscopic morphology of the WG dough of the present invention (kneaded 20 times, rough surface, poor uniformity);

[0031] Figure 8 This is a cross-sectional SEM image of the WG dough of the present invention (kneaded 20 times, network structure destroyed);

[0032] Figure 9 The macroscopic morphology of the WG dough of the present invention (hot-pressed at 100°C for 5 min, with pores on the surface and localized drying).

[0033] Figure 10 This is a cross-sectional SEM image of the WG dough of the present invention (hot-pressed at 100°C for 5 min, densified).

[0034] Figure 11 The macroscopic morphology of the WG dough of the present invention (hot-pressed at 80°C for 10 min, densified);

[0035] Figure 12 This is a cross-sectional SEM image of the WG dough of the present invention (hot-pressed at 80°C for 10 min, resulting in reduced pores and uneven structure).

[0036] Figure 13 The WG film of premixed glycerol of the present invention;

[0037] Figure 14 Examples 5 of this invention show the WG film before drying and the WG film after drying.

[0038] Figure 15 This is a plate count diagram of the antibacterial plate of WG-n Cu²⁺-GI of the present invention. Detailed Implementation

[0039] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0040] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0041] Secondly, the term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places throughout this specification does not necessarily refer to the same embodiment, nor is it a single embodiment or an embodiment selectively excluded from other embodiments.

[0042] Example 1

[0043] This embodiment provides a method for preparing a pure wheat gluten (WG) membrane.

[0044] Specifically:

[0045] (1) Preparation of WG dough: Take 5g of wheat gluten protein powder and 7.5g of deionized water (material-liquid ratio 1:1.5) and put them in a container. Add water and stir to mix. Knead the dough repeatedly 15 times. After kneading, let it stand for 30 minutes to relieve stress and obtain WG dough.

[0046] (2) Hot pressing and shaping: Divide the WG dough into small pieces of 1±0.05g, place them on an 80℃ heating plate, cover them with a heating plate of the same temperature and apply a 2kg weight, and hot press for 5min to obtain WG film.

[0047] like Figure 4 As shown, when the material-to-liquid ratio is 1:1.5, the WG dough exhibits a fine and smooth macroscopic morphology, with a uniform honeycomb-like three-dimensional network structure in its cross-section, providing a good structural foundation for subsequent hot pressing. As shown in the figure, the WG film obtained after hot pressing at 80℃ for 5 minutes has a smooth surface and uniformly distributed pores in its cross-section.

[0048] The results show that the membrane under these process conditions has certain flexibility and initial viscosity, and can be used as a base membrane for subsequent functional modification.

[0049] Comparative Example 1

[0050] This comparative example provides the preparation of pure wheat gluten protein membranes under different process parameters:

[0051] Specifically: 1) Material-to-liquid ratio: Take 5g of wheat gluten protein powder and 10g of deionized water (material-to-liquid ratio 1:2), and the remaining kneading and hot pressing conditions are the same as in Example 1.

[0052] As shown in the figure, when the ratio of liquid to feed is too high, the dough has a loose macroscopic shape, uneven forming, and poor continuity of cross-sectional pores, which is not conducive to forming a uniform three-dimensional network structure.

[0053] 2) Comparative example of kneading times: material-liquid ratio 1:1.5, knead 20 times, other conditions are the same as in Example 1.

[0054] As shown in the figure, excessive kneading results in a rough dough surface, poor uniformity, and damage to the network structure.

[0055] 3) Comparative example of hot pressing conditions: Hot pressing was performed at 100℃ or 80℃ for 10 minutes, with other conditions the same as in Example 1. As shown in the figure, when the hot pressing temperature is too high or the time is too long, pores and localized drying occur on the film surface, the cross-section shows excessive densification, and the pore deformation is obvious, affecting the flexibility and performance of the film.

[0056] The comparative results above show that the material-to-liquid ratio, the number of kneading cycles, and the hot-pressing temperature and time have a significant impact on the microstructure and macroscopic morphology of WG dough and film. Only within the appropriate parameter range can a base film with uniform structure and good performance be obtained.

[0057] Example 2

[0058] This embodiment provides a method for preparing a self-adhesive, high-toughness, antibacterial wheat gluten protein film (WG-Cu²⁺-GI), specifically:

[0059] (1) Preparation of WG dough: Same as in Example 1 (material-liquid ratio 1:1.5, knead 15 times, let stand for 30 minutes).

[0060] (2) Hot pressing: Same as in Example 1 (80℃, 2kg, 5min) to obtain WG film.

[0061] (3) Prepare a 100 μmol / L CuSO4 solution: accurately weigh 0.025 g CuSO4·5H2O powder, dissolve it in deionized water, and make up to 1 L.

[0062] (4) Impregnation loading: The WG membrane prepared in step (2) is immersed in the above CuSO4 solution and left to stand at room temperature for 2 hours to allow the active groups on the WG molecular chain to coordinate with Cu²⁺. After removal, the surface is rinsed with deionized water and dried to obtain the WG-Cu²⁺ membrane.

[0063] (5) Prepare a 50% glycerol-water binary solution: Take 50 mL of glycerol and add 50 mL of deionized water, stir and mix well.

[0064] (6) Solvent replacement treatment: Immerse the WG-Cu²⁺ membrane in the above glycerol-water binary solution and let it stand at room temperature for 1 hour. After taking it out, wipe the surface liquid with filter paper to obtain the WG-Cu²⁺-GI membrane.

[0065] Example 3

[0066] This embodiment provides the preparation of antibacterial films with different Cu²⁺ concentrations, specifically:

[0067] The preparation method is basically the same as in Example 2, except that the concentration of CuSO4 solution in step (3) is replaced with 1 μmol / L, 10 μmol / L and 1000 μmol / L respectively, and WG-1Cu²⁺-GI membrane, WG-10Cu²⁺-GI membrane and WG-1000Cu²⁺-GI membrane are prepared accordingly.

[0068] like Figure 15 As shown, the antibacterial plate count results of WG-nCu²⁺-GI membranes at different Cu²⁺ concentrations indicate that the antibacterial effect is enhanced with increasing Cu²⁺ concentration.

[0069] Example 4

[0070] This example provides a premixed glycerol control experiment, specifically:

[0071] In the hydration stage of step (1) of Example 1, glycerol equivalent to 50% of the final glycerol amount was added in advance, and the remaining steps were the same as those in Example 2.

[0072] (1) Preparation of WG dough: Take 0.5g of wheat gluten protein powder and 0.75mL of deionized water (material-liquid ratio 1:1.5) and put them in a container. Add 0.125mL of glycerin, add water and stir to mix. Knead the dough repeatedly 15 times. After kneading, let it stand for 30min to relieve stress and obtain WG dough.

[0073] (2) Hot pressing and shaping: Place the WG dough on an 80℃ heating plate, cover it with a heating plate of the same temperature and apply a 2kg weight, and hot press for 5 minutes to obtain the WG film.

[0074] The results are as follows Figure 13 The results show that, due to the influence of small molecule glycerol on glutenin and gliadin after premixing, it is difficult to obtain a better molecular network structure through kneading and hot pressing, resulting in uneven membrane surface and thus affecting its mechanical properties. This demonstrates that the post-solvent replacement treatment method has unique advantages.

[0075] Example 5

[0076] This embodiment provides a control experiment for the solution casting method. Specifically, a control experiment for the solution casting method is set up with reference to the solution casting process of wheat gluten protein reported in the literature.

[0077] (1) Preparation of film-forming solution: Take 0.5g of wheat gluten protein powder and add it to 5mL of 40% ethanol aqueous solution (measure 2mL of anhydrous ethanol with a graduated cylinder and mix with 3mL of deionized water). Adjust the pH to 11-12 with 2mol / L NaOH (weigh 0.40g of sodium hydroxide solid, dissolve it in a small amount of deionized water and make up to 5mL). Add 0.125mL of glycerol and stir to form a uniform film-forming solution.

[0078] (2) Casting film: Pour the film-forming solution into a horizontal mold with a diameter of 4cm, spread it out, and dry it in a 60℃ oven for 1 hour until constant weight to obtain the WG-GI film prepared by solution casting.

[0079] like Figure 14 The results show that, compared to Example 2, the cast film did not involve mechanical intervention of the protein molecules, resulting in a lack of entanglement and cross-linking between molecular chains. Although it could form a film, the film's strength and toughness were significantly insufficient, making demolding difficult and prone to breakage. Moreover, it required the addition of ethanol and NaOH as additives, posing a risk of organic solvent and alkali residue. In contrast, the present invention uses a kneading-hot pressing process, requiring no additives, making the process simpler and safer.

[0080] Furthermore, the performance testing methods are as follows:

[0081] (1) Tensile mechanical properties: Universal testing machine, sample 30mm×10mm, spacing 20mm, tensile speed 20mm / min, tested after equilibration at 20℃ and 50% humidity for 72h, and calculated tensile strength, elongation at break and tensile toughness (n=3).

[0082] (2) Adhesion performance: Fresh pigskin substrate, overlap area 1.5cm×1.5cm, pre-compression 5kPa for 60s, peel test at 20mm / min.

[0083] (3) Antibacterial properties: Vibration contact method, 0.1g membrane with 3~3.75×10 5 Plate counting was performed after 18 hours of contact with CFU / mL bacterial culture.

[0084] (4) Cytotoxicity: CCK-8 method, 0.1 g / mL extract was co-cultured with L929 cells for 24 h and 48 h.

[0085] (5) Anti-drying performance: Observe the state and mechanical properties after being placed in the air for 24 hours.

[0086] The test results are as follows:

[0087] Example 1 (pure WG film): tensile toughness 54.71±3.89 kJ / m³, tensile strength 20.09±0.95 kPa, elongation at break 410.80±4.01%, skin adhesion strength 20.13±0.86 kPa.

[0088] Example 2 (WG-Cu²⁺-GI film): Tensile toughness 787.29±4.52 kJ / m³, tensile strength 252.93±1.87 kPa, elongation at break 514.65±3.26%, skin adhesion strength 46.82±0.58 kPa. Compared with Example 1, the tensile toughness increased by approximately 13.4 times, the tensile strength increased by approximately 11.6 times, and the skin adhesion strength increased by approximately 1.3 times.

[0089] The membrane from Example 2 remained flexible after being exposed to air for 24 hours, retaining a tensile toughness of 628.23 ± 4.38 kJ / m³, demonstrating good resistance to drying. In Example 3, a concentration of 100 μmol / L achieved a good balance between antibacterial properties and cell safety.

[0090] Furthermore, through systematic comparison of Examples 1-5 and comparative examples, it can be seen that the specific process sequence of the present invention, namely "kneading-hot pressing molding-Cu²⁺ post-impregnation coordination-glycerol post-solvent replacement", precisely regulates the wheat gluten protein molecular network and produces synergistic technical effects.

[0091] This effect is not a simple superposition of existing hot-pressing WG film technology or Cu²⁺ antibacterial modification technology, but rather overcomes the technical biases of existing technologies such as poor self-adhesion, insufficient toughness, weak resistance to drying, and sudden release of antibacterial agents. Figures 1 to 14 The results clearly show that different process parameters affect the microstructure and macroscopic morphology of the dough and film. Only under optimized conditions (material-to-liquid ratio 1:1.5, kneading 15 times, and hot pressing at 80℃ for 5 minutes) can a uniformly structured base film be obtained. Based on this, Cu²⁺ coordination crosslinking ( Figure 15This process imparts long-lasting antibacterial properties to the membrane, while the glycerol post-solvent replacement treatment enhances the membrane's toughness, self-adhesion, and anti-drying ability.

[0092] The synergistic effect of the above-mentioned multi-step process has produced a significant performance improvement effect. The resulting WG-Cu²⁺-GI membrane has intrinsic self-adhesion, high toughness and antibacterial properties, and can better adapt to the dynamic mechanical environment of the joint, demonstrating the superiority of the technical solution of the present invention.

Claims

1. A self-adhesive, high-toughness, antibacterial wheat gluten protein film, characterized in that: It is prepared by hydrating and kneading wheat gluten protein powder with a protein content of 80±2% to form dough, hot pressing it into shape, and then subjecting it to copper ion impregnation loading and glycerol-water binary solvent replacement treatment in sequence.

2. The self-adhesive, high-toughness, antibacterial wheat gluten protein film as described in claim 1, characterized in that: The membrane is obtained by kneading dough with a uniform three-dimensional network structure, and then hot-pressed into a sheet-like film. Copper ions are stably loaded in the protein network in the form of coordination bonds, and glycerol molecules enter the network through solvent displacement to reconstruct hydrogen bonds.

3. The self-adhesive, high-toughness, antibacterial wheat gluten protein film as described in claim 2, characterized in that: Copper ion loading is achieved by impregnation with CuSO4 solution with a concentration of 1–1000 μmol / L.

4. The self-adhesive, high-toughness, antibacterial wheat gluten protein film as described in claim 3, characterized in that: Includes the following steps: The volume fraction of glycerol in a glycerol-water binary solution is 25% to 75%.

5. A method for preparing a self-adhesive, high-toughness, antibacterial wheat gluten protein film as described in any one of claims 1-4, characterized in that, Includes the following steps: (1) Mix wheat gluten protein powder with deionized water at a ratio of 1:1 to 1:2, stir and knead for 10 to 20 times, and let stand for 15 to 60 minutes to obtain dough; (2) The dough is hot-pressed at 60-100℃ and 2kg pressure for 3-10 minutes to obtain WG film; (3) Immerse the WG film in 1-1000 μmol / L CuSO4 solution for 1-4 h, rinse and dry to obtain Cu²⁺ loaded film; (4) Immerse the Cu²⁺-loaded membrane in a glycerol-water binary solution with a glycerol volume fraction of 25% to 75% for 0.5 to 2 hours, and then wipe it dry to obtain the target membrane.

6. The method for preparing a self-adhesive, high-toughness, antibacterial wheat gluten protein film as described in claim 5, characterized in that: In step (1), the ratio of material to liquid is 1:1.5, knead 15 times, and let stand for 30 minutes.

7. The method for preparing a self-adhesive, high-toughness, antibacterial wheat gluten protein film as described in claim 6, characterized in that: In step (2), the hot pressing temperature is 80℃ and the hot pressing time is 5min.

8. The method for preparing a self-adhesive, high-toughness, antibacterial wheat gluten protein film as described in claim 7, characterized in that: In step (3), the concentration of CuSO4 solution is 100 μmol / L and the soaking time is 2 h; in step (4), the volume fraction of glycerol is 50% and the soaking time is 1 h.

9. The application of the membrane prepared by the method for preparing a self-adhesive, high-toughness, antibacterial wheat gluten protein membrane as described in claim 8 in the preparation of wound dressings for joint areas.

10. The application according to claim 9, characterized in that, The joints are movable joints such as fingers, knees, or elbows, and the membrane can maintain good adhesion in dynamic stretching, compression, and shearing environments.

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