Piezoelectric anti-inflammatory fibrous membrane / hydrogel composite dressing and preparation method thereof

Abstract

The invention belongs to the technical field of biomedical materials, and provides a piezoelectric anti-inflammatory fibrous membrane / hydrogel composite dressing and a preparation method thereof, and the preparation method comprises the following steps: purifying bacterial cellulose to remove residual strains and other components; carrying out hydroxylation surface treatment on barium titanate; uniformly mixing the purified bacterial cellulose hydroxylated barium titanate, and performing vacuum filtration to obtain a bacterial cellulose / hydroxylated barium titanate composite fiber membrane; the preparation method comprises the following steps: preparing a polydopamine solution, then adding epigallocatechin-3-gallate, acrylamide, N, N-methylene bisacrylamide and tetramethylethylenediamine, and fully stirring to obtain a hydrogel precursor; and finally, putting the obtained composite fiber membrane into a mold, and pouring the hydrogel precursor to obtain the composite fiber membrane / hydrogel composite dressing. The prepared dressing can promote wound healing through self power supply, ultrasound and application of mechanical stimulation, can also provide a moist environment, reduce inflammatory response of wounds and provide excellent oxidation resistance, and thus the wound healing effect of the dressing is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of biomedical materials, and in particular to a fiber membrane / hydrogel composite dressing with piezoelectric anti-inflammatory function and a preparation method thereof. Background Art

[0002] Chronic wounds are a common type of complex, difficult-to-heal wound, and are associated with a range of costly complications. Intrinsic pathogenic factors (such as neuropathy, vascular problems, and diabetes) can cause complex systemic effects, while extrinsic factors (such as wound infection, pressure, etc.) can also lead to difficult wound healing.

[0003] At present, there are many different treatment methods for wound healing, such as the use of bioactive materials, advanced growth factor-mediated therapy, and structural simulation of natural extracellular matrix. However, these methods still face the challenges of inaccurate control and loss of bioactivity. The focus of the present invention is to design a wound dressing that is safe, efficient, accelerates healing, and improves the quality of healing. Studies have shown that electrical stimulation can promote the growth and migration of skin fibroblasts, enhance the secretion of growth factors, and promote the transformation of fibroblasts to myofibroblasts, thereby promoting wound healing. Therefore, the introduction of bioelectric dressings is an effective method in electrical stimulation therapy. Piezoelectric materials can convert mechanical energy into electrical energy under the action of external forces. Due to this self-generating property, piezoelectric materials are suitable for the preparation of wireless, simple, and flexible microcurrent dressings. Traditional electrical stimulation is limited to large-scale use due to the disadvantages of large equipment and the need for professional operation. Ultrasound therapy, due to its biocompatibility, low energy attenuation, non-invasiveness, and high penetration, makes it an effective auxiliary treatment method for wound healing. The combination of ultrasound and piezoelectric polymers is conducive to the generation of concentrated power transmission, which can penetrate the wound area and further promote wound healing. Summary of the invention

[0004] In view of the problems in the prior art, the present invention designs a piezoelectric anti-inflammatory fiber membrane / hydrogel composite dressing, which converts it into an electric field through mechanical action, and can reduce inflammation, resist oxidation, provide a moist healing environment, and promote wound healing.

[0005] To achieve the above technical objectives, the present invention provides a method for preparing a piezoelectric anti-inflammatory fiber membrane / hydrogel composite dressing, the method comprising at least the following steps:

[0006] Step 1: Purify bacterial cellulose to remove residual strains and other components;

[0007] Step 2: hydroxylating the barium titanate surface;

[0008] Step 3: uniformly mixing the purified bacterial cellulose obtained in step 1 and the hydroxylated barium titanate obtained in step 2 to obtain a suspension;

[0009] Step 4: vacuum filtration of the suspension obtained in step 3 to obtain a bacterial cellulose / hydroxylated barium titanate composite fiber membrane;

[0010] Step 5: prepare a polydopamine solution, add epigallocatechin-3-gallate, acrylamide, N,N-methylenebisacrylamide and tetramethylethylenediamine, and stir thoroughly to obtain a hydrogel precursor;

[0011] Step 6: Place the composite fiber membrane obtained in step 4 into a mold, and then pour the hydrogel precursor obtained in step 5 into it to obtain the composite fiber membrane / hydrogel composite dressing.

[0012] In some technical solutions of the present invention, step 1 includes the following steps: placing the bacterial cellulose membrane in a sodium hydroxide solution, heating it in a water bath to remove residual strains, and thoroughly washing it with deionized water until it is neutralized.

[0013] In some technical solutions of the present invention, the heating temperature of the water bath is 78-82° C., and the heating time is 3-5 hours.

[0014] In some technical solutions of the present invention, the hydroxylation surface treatment of barium titanate in step 2 comprises the following steps:

[0015] Step 2.1: Adding nano-barium titanate into hydrogen peroxide solution;

[0016] Step 2.2: After ultrasonication, add to a four-necked flask and reflux at 100-110°C for 3-5h;

[0017] Step 2.3: Wash with deionized water 2-3 times and dry to obtain hydroxylated barium titanate powder.

[0018] In some preferred technical solutions of the present invention, the mass ratio of nano-barium titanate to hydrogen peroxide solution is 1:6.

[0019] In some technical solutions of the present invention, the step 3 mixing step mainly includes the following operations:

[0020] Step 3.1: Place bacterial cellulose in water and use a high-speed homogenizer to break it into a bacterial cellulose water suspension;

[0021] Step 3.2: ultrasonically disperse the barium titanate hydroxylate nanoparticles in deionized water, and then mix them with the bacterial cellulose aqueous suspension under vigorous stirring in a homogenizer to ensure sufficient mixing;

[0022] Step 3.3: The mixed suspension is vacuum filtered through a microporous membrane, followed by pressing and drying to form a composite cellulose membrane.

[0023] In some preferred technical solutions, the mass fraction of the hydroxylated barium titanate in the bacterial cellulose is 20-100%, specifically, 20%, 30%, 40%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%. The barium titanate treated by hydroxylation can further improve its adhesion performance on the cellulose surface while retaining its piezoelectric effect, thereby increasing the loading amount of the barium titanate component on the bacterial cellulose and improving the healing effect of the dressing under mechanical stimulation.

[0024] In some preferred technical solutions, the rotation speed of the homogenizer is 1000-1500 rpm.

[0025] In some technical solutions of the present invention, the step 5 of preparing the hydrogel specifically includes the following operations:

[0026] Step 5.1: dissolving dopamine hydrochloride and ammonium persulfate in deionized water and stirring at room temperature for 25-30 minutes to form a polydopamine solution;

[0027] Step 5.2: Add epigallocatechin-3-gallate and stir for 10-15 minutes;

[0028] Step 5.3: Add acrylamide and N,N-methylenebisacrylamide and stir for 10-15 minutes.

[0029] Step 5.4: Finally, add tetramethylethylenediamine and stir rapidly with a glass rod to form a hydrogel precursor.

[0030] In some technical solutions of the present invention, the mass fraction of epigallocatechin-3-gallate added is 1-10%, and specific examples include 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, and 10%. By loading epigallocatechin-3-gallate in the hydrogel, excellent antioxidant properties can be exhibited, which is a good solution to the problem of excessive active oxygen in the wound.

[0031] The present invention also provides a piezoelectric anti-inflammatory fiber membrane / hydrogel composite dressing, and the dressing is prepared by the preparation method.

[0032] The beneficial effects brought by the technical solution provided by the present invention are:

[0033] 1. Use bacterial cellulose as the fiber membrane skeleton, load nanoparticles with high-voltage electrical properties, mix them evenly through high-speed stirring, and obtain fiber membrane through vacuum filtration, so as to firmly load the nanoparticles with high-voltage electrical effect in the nanofibers. The prepared composite fiber membrane / hydrogel composite dressing can promote wound healing through self-powered, ultrasonic, and mechanical stimulation.

[0034] 2. At the same time, the composite fiber membrane / hydrogel composite dressing prepared by the present invention, the hydrogel layer can not only provide a moist environment for the composite dressing, but also reduce the inflammatory response of the wound, provide excellent antioxidant properties, and thus improve the wound healing effect of the dressing.

[0035] 3. The fiber membrane / hydrogel composite dressing prepared by the present invention can be applied to special alkaline skin to achieve the effect of sustained drug release. Epigallocatechin-3-gallate added to the fiber membrane / hydrogel composite dressing has bactericidal, anti-inflammatory and antioxidant effects, and can be released locally in a controlled manner, thereby enhancing wound healing by inhibiting inflammatory reactions, promoting the proliferation of fibroblasts and the synthesis of collagen fibers. DETAILED DESCRIPTION

[0036] The following is a clear and complete description of the technical solutions in the present invention in conjunction with the embodiments of the present invention. The described embodiments are part of the embodiments of the present invention, but not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] Embodiment 1:

[0038] Step 1: Place the bacterial cellulose membrane in a sodium hydroxide solution, wash it in a water bath at 80°C for 4 hours to remove residual strains and other components, and then wash it thoroughly with deionized water until neutralized.

[0039] Step 2: Add nano-barium titanate to hydrogen peroxide solution, add it to a four-necked flask after ultrasonication, and reflux it at 105°C for 4 hours, wash it twice with deionized water, and dry it to obtain hydroxylated barium titanate powder, wherein the ratio of barium titanate to hydrogen peroxide solution is 1:6.

[0040] Step 3: Place bacterial cellulose in water and use a high-speed homogenizer to break it into a bacterial cellulose water suspension. The hydroxylated barium titanate nanoparticles are ultrasonically dispersed in deionized water, and then mixed with the bacterial cellulose water suspension under vigorous stirring by a homogenizer to ensure sufficient mixing, and the mixed suspension is vacuum filtered through a microporous membrane, followed by pressing and drying to form a composite fiber membrane, in which the hydroxylated barium titanate accounts for 20% of the bacterial cellulose, and the speed of the homogenizer is 1200 rpm.

[0041] Step 4: Dissolve 0.03 g of dopamine hydrochloride in deionized water, add 0.4 g of ammonium persulfate and stir at room temperature for 30 minutes to form a polydopamine solution, add 1% epigallocatechin-3-gallate and stir for 15 minutes, then add 5 g of acrylamide and 0.03 g of N,N-methylenebisacrylamide, stir for 15 minutes, and finally add 40 μL of tetramethylethylenediamine and stir quickly with a glass rod to form a hydrogel precursor.

[0042] Step 5: Place the composite fiber membrane obtained in step 3 into a mold, and then pour in the hydrogel precursor obtained in step 4 to obtain a composite fiber membrane / hydrogel composite dressing.

[0043] Example 2

[0044] Step 1: Place the bacterial cellulose membrane in a sodium hydroxide solution, wash it in a water bath at 80°C for 4 hours to remove residual strains and other components, and then wash it thoroughly with deionized water until neutralized.

[0045] Step 2: Add nano-barium titanate to hydrogen peroxide solution, add it to a four-necked flask after ultrasonication, and reflux it at 105°C for 4 hours, wash it twice with deionized water, and dry it to obtain hydroxylated barium titanate powder, wherein the ratio of barium titanate to hydrogen peroxide solution is 1:6.

[0046] Step 3: Place bacterial cellulose in water and use a high-speed homogenizer to break it into a water suspension of bacterial cellulose. The hydroxylated barium titanate nanoparticles are ultrasonically dispersed in deionized water, and then mixed with the bacterial cellulose water suspension under vigorous stirring of a homogenizer to ensure sufficient mixing, and the mixed suspension is vacuum filtered through a microporous membrane, followed by pressing and drying to form a composite fiber membrane, in which the hydroxylated barium titanate accounts for 40% of the bacterial cellulose, and the speed of the homogenizer is 1200rpm.

[0047] Step 4: Dissolve 0.03 g of dopamine hydrochloride in deionized water, add 0.4 g of ammonium persulfate and stir at room temperature for 30 minutes to form a polydopamine solution, add 3% epigallocatechin-3-gallate and stir for 15 minutes, then add 5 g of acrylamide and 0.03 g of N,N-methylenebisacrylamide, stir for 15 minutes, and finally add 40 μL of tetramethylethylenediamine and stir quickly with a glass rod to form a hydrogel precursor.

[0048] Step 5: Place the composite fiber membrane obtained in step 3 into a mold, and then pour in the hydrogel precursor obtained in step 4 to obtain a composite fiber membrane / hydrogel composite dressing.

[0049] Example 3

[0050] Step 1: Place the bacterial cellulose membrane in a sodium hydroxide solution, wash it in a water bath at 80°C for 4 hours to remove residual strains and other components, and then wash it thoroughly with deionized water until neutralized.

[0051] Step 2: Add nano-barium titanate to hydrogen peroxide solution, add it to a four-necked flask after ultrasonication, and reflux it at 105°C for 4 hours, wash it twice with deionized water, and dry it to obtain hydroxylated barium titanate powder, wherein the ratio of barium titanate to hydrogen peroxide solution is 1:6.

[0052] Step 3: Place bacterial cellulose in water and use a high-speed homogenizer to break it into a water suspension of bacterial cellulose. Ultrasonic dispersion of hydroxylated barium titanate nanoparticles in deionized water, then mix with the bacterial cellulose water suspension under vigorous stirring of a homogenizer to ensure adequate mixing, vacuum filter the mixed suspension with a microporous membrane, and then press and dry to form a composite fiber membrane, in which hydroxylated barium titanate accounts for 60% of the bacterial cellulose, and the speed of the homogenizer is 1200 rpm.

[0053] Step 4: Dissolve 0.03 g of dopamine hydrochloride in deionized water, add 0.4 g of ammonium persulfate and stir at room temperature for 30 minutes to form a polydopamine solution, add 5% epigallocatechin-3-gallate and stir for 15 minutes, then add 5 g of acrylamide and 0.03 g of N,N-methylenebisacrylamide, stir for 15 minutes, and finally add 40 μL of tetramethylethylenediamine and stir quickly with a glass rod to form a hydrogel precursor.

[0054] Step 5: Place the composite fiber membrane obtained in step 3 into a mold, and then pour in the hydrogel precursor obtained in step 4 to obtain a composite fiber membrane / hydrogel composite dressing.

[0055] Example 4

[0056] Step 1: Place the bacterial cellulose membrane in a sodium hydroxide solution, wash it in a water bath at 80°C for 4 hours to remove residual strains and other components, and then wash it thoroughly with deionized water until neutralized.

[0057] Step 2: Add nano-barium titanate to hydrogen peroxide solution, add it to a four-necked flask after ultrasonication, and reflux it at 105°C for 4 hours, wash it twice with deionized water, and dry it to obtain hydroxylated barium titanate powder, wherein the ratio of barium titanate to hydrogen peroxide solution is 1:6.

[0058] Step 3: Place bacterial cellulose in water and use a high-speed homogenizer to break it into a water suspension of bacterial cellulose. Ultrasonic dispersion of hydroxylated barium titanate nanoparticles in deionized water, then mix with the bacterial cellulose water suspension under vigorous stirring of a homogenizer to ensure adequate mixing, vacuum filter the mixed suspension with a microporous membrane, and then press and dry to form a composite fiber membrane, in which hydroxylated barium titanate accounts for 80% of the bacterial cellulose, and the speed of the homogenizer is 1200 rpm.

[0059] Step 4: Dissolve 0.03 g of dopamine hydrochloride in deionized water, add 0.4 g of ammonium persulfate and stir at room temperature for 30 minutes to form a polydopamine solution, add 7% epigallocatechin-3-gallate and stir for 15 minutes, then add 5 g of acrylamide and 0.03 g of N,N-methylenebisacrylamide, stir for 15 minutes, and finally add 40 μL of tetramethylethylenediamine and stir quickly with a glass rod to form a hydrogel precursor.

[0060] Step 5: Place the composite fiber membrane obtained in step 3 into a mold, and then pour in the hydrogel precursor obtained in step 4 to obtain a composite fiber membrane / hydrogel composite dressing.

[0061] Example 5

[0062] Step 1: Place the bacterial cellulose membrane in a sodium hydroxide solution, wash it in a water bath at 80°C for 4 hours to remove residual strains and other components, and then wash it thoroughly with deionized water until neutralized.

[0063] Step 2: Add nano-barium titanate to hydrogen peroxide solution, add it to a four-necked flask after ultrasonication, and reflux it at 105°C for 4 hours, wash it twice with deionized water, and dry it to obtain hydroxylated barium titanate powder, wherein the ratio of barium titanate to hydrogen peroxide solution is 1:6.

[0064] Step 3: Place bacterial cellulose in water and use a high-speed homogenizer to break it into a water suspension of bacterial cellulose. Ultrasonic dispersion of hydroxylated barium titanate nanoparticles in deionized water, then mix with the bacterial cellulose water suspension under vigorous stirring of a homogenizer to ensure adequate mixing, vacuum filter the mixed suspension with a microporous membrane, and then press and dry to form a composite fiber membrane, in which hydroxylated barium titanate accounts for 100% of the bacterial cellulose, and the speed of the homogenizer is 1200 rpm.

[0065] Step 4: Dissolve 0.03 g of dopamine hydrochloride in deionized water, add 0.4 g of ammonium persulfate and stir at room temperature for 30 minutes to form a polydopamine solution, add 9% epigallocatechin-3-gallate and stir for 15 minutes, then add 5 g of acrylamide and 0.03 g of N,N-methylenebisacrylamide, stir for 15 minutes, and finally add 40 μL of tetramethylethylenediamine and stir quickly with a glass rod to form a hydrogel precursor.

[0066] Step 5: Place the composite fiber membrane obtained in step 3 into a mold, and then pour in the hydrogel precursor obtained in step 4 to obtain a composite fiber membrane / hydrogel composite dressing.

[0067] Comparative Example 1

[0068] The only difference compared with Example 1 is that epigallocatechin-3-gallate is not added to the hydrogel layer.

[0069] Comparative Example 2

[0070] Compared with Example 1, the only difference is that no bacterial cellulose / hydroxylated barium titanate composite fiber membrane is added.

[0071] Test experiment:

[0072] 1. Piezoelectric test: The dressings prepared in Examples 1-5 and Comparative Examples 1 and 2 were encapsulated with insulating tape to form a sandwich structure, and an electrometer was used to collect the piezoelectric output signal of the sample under mechanical external force or ultrasound. In the mechanical pressure test, the movement frequency of the LinMot linear motor was set to 1.0 Hz and the speed was set to 0.1 m / s; in the ultrasonic test, the frequency of the ultrasonic device was 1 MHz and the pulse time was 1.4 ms.

[0073] 2. Drug sustained release performance test: Test the drug release rates of Examples 1-5 and Comparative Examples 1 and 2 at different time points in a phosphate buffered saline solution at pH = 7.4.

[0074] 3. Antioxidant performance test: The free radical scavenging ability of Examples 1-5 and Comparative Examples 1 and 2 in 2,2-diphenyl-1-picrylhydrazyl solution was tested using a UV-visible spectrophotometer.

[0075] 4. Mechanical stimulation experiment: The untreated group was used as the blank group, and Examples 1-5 and Comparative Examples 1 and 2 were placed at the bottom of the well plate and ultrasonically stimulated using an ultrasonic machine. After culturing for 1 day, 3 days, and 5 days, the absorbance of each group was measured using an ELISA instrument, and the activity of the cells was evaluated.

[0076] 5. Anti-inflammatory performance experiment: The wound tissue area of ​​mice was detected by ELISA method, and the untreated wound was used as a blank group. Then, the wound was treated with Examples 1-5 and Comparative Examples 1 and 2, and the concentrations of inflammatory cytokines tumor necrosis factor α (TNF-α) and interleukin β (IL-1β) in the cells were detected to evaluate the anti-inflammatory performance of the samples.

[0077] Test result description:

[0078] 1. Piezoelectric performance test:

[0079] Table 1 Piezoelectric performance test results

[0080]

[0081] As shown in Table 1, after adding bacterial cellulose / hydroxylated barium titanate composite fiber membrane to Examples 1-5, a significant piezoelectric effect will be produced. Mechanical pressure test or ultrasonic test shows that the output voltage and current will increase with the increase of the amount of hydroxylated barium titanate added.

[0082] 2. Drug sustained release performance test

[0083] Table 2 Drug sustained release test results

[0084] Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 12h / ％ 3.4 6.2 10.3 15.1 16.3 0 2.3 192h / ％ 19.5 33.4 57.1 72.3 93.4 0 16.6

[0085] It can be seen from Table 2 that the drug release rate of the composite fiber membrane / hydrogel dressing prepared in Examples 1-5 can be as high as over 90% in 192 hours, which is more conducive to promoting wound healing.

[0086] 3. Antioxidant performance test

[0087] Table 3 Antioxidant performance test results

[0088]

[0089] As can be seen from Table 3, examples 1-5 added epigallocatechin-3-gallate, and the free radical scavenging rate was able to reach 23-81%, while comparative example 1 did not add epigallocatechin-3-gallate, and the free radical scavenging rate was only 2%, and the antioxidant activity was almost negligible. It can be seen that the addition of epigallocatechin-3-gallate can provide excellent antioxidant properties for the composite fiber membrane / hydrogel dressing, improve the problem of excessive reactive oxygen in the wound, and thus promote wound healing.

[0090] 4. Mechanical stimulation to promote healing experiment

[0091] Table 4-1 Test results without adding mechanical stimulation

[0092] Blank Group Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 1 day 0.21 0.27 0.30 0.32 0.36 0.41 0.25 0.23 3 days 0.62 0.63 0.68 0.73 0.77 0.82 0.61 0.62 5 days 0.92 0.96 0.98 1.02 1.05 1.13 0.92 0.93

[0093] Table 4-2 Test results after adding mechanical stimulation

[0094] Blank Group Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 1 day 0.22 0.32 0.45 0.54 0.76 1.07 0.30 0.25 3 days 0.63 0.76 1.02 1.24 1.62 2.13 0.72 0.64 5 days 0.92 1.15 1.47 1.73 2.21 2.94 1.11 0.95

[0095] Combining Tables 4-1 and 4-2, it can be seen that after adding mechanical stimulation, the number of cells in the examples increased significantly, indicating that the dressings prepared in Examples 1-5 can promote cell proliferation under mechanical stimulation conditions, thereby improving the wound healing effect.

[0096] 5. Anti-inflammatory properties test

[0097] Table 5 Anti-inflammatory performance test results

[0098]

[0099] As shown in Table 5, after epigallocatechin-3-gallate was added to Example 1-5, TNF-α and IL-1β decreased more significantly compared with the blank group, indicating that the composite dressing with epigallocatechin-3-gallate can effectively inhibit the inflammatory response and achieve an anti-inflammatory effect.

[0100] Comprehensive experimental tests show that the composite fiber membrane / hydrogel prepared in Examples 1-5 has a high-voltage electric effect, can promote wound healing by self-powered and ultrasonic mechanical stimulation, and at the same time, the polydopamine hydrogel layer loaded with gallicate-3-gallate has anti-inflammatory and antioxidant properties, thereby reducing the inflammatory response and reactive oxygen content of the wound, and further promoting wound healing.

[0101] Finally, a few points should be explained: Although the present invention has been described in detail above with general descriptions and specific embodiments, on the basis of the present invention, the above embodiments are only used to illustrate the technical solution of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that: it is still possible to modify the technical solutions recorded in the aforementioned embodiments, or to replace part or all of the technical features therein with equivalents; and these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the present invention.

Claims

1. A method for preparing a piezoelectric anti-inflammatory fiber membrane / hydrogel composite dressing, It is characterized in that At least the following steps are included: Step 1: Purify bacterial cellulose to remove residual strains and other components; Step 2: Surface treatment of barium titanate by hydroxylation. Step 3: uniformly mixing the purified bacterial cellulose obtained in step 1 and the hydroxylated barium titanate obtained in step 2 to obtain a suspension; Step 4: vacuum filtration of the suspension obtained in step 3 to obtain a bacterial cellulose / hydroxylated barium titanate composite fiber membrane; Step 5: prepare a polydopamine solution, add epigallocatechin-3-gallate, acrylamide, N,N-methylenebisacrylamide and tetramethylethylenediamine, and stir thoroughly to obtain a hydrogel precursor; Step 6: Place the composite fiber membrane obtained in step 4 into a mold, and then pour the hydrogel precursor obtained in step 5 into it to obtain the composite fiber membrane / hydrogel composite dressing.

2. The method for preparing the composite dressing according to claim 1, It is characterized in that The step 1 comprises the following steps: placing the bacterial cellulose membrane in a sodium hydroxide solution, heating it in a water bath to remove residual strains, and thoroughly washing it with deionized water until it is neutralized.

3. The method for preparing the composite dressing according to claim 1, It is characterized in that The hydroxylation surface treatment of barium titanate in step 2 comprises the following steps: Step 2.1: Adding nano-barium titanate into hydrogen peroxide solution; Step 2.2: After ultrasonication, add to a four-necked flask and reflux at 100-110°C for 3-5h; Step 2.3: Wash with deionized water 2-3 times and dry to obtain hydroxylated barium titanate powder.

4. The method for preparing the composite dressing according to claim 2, It is characterized in that The mass ratio of the nano-barium titanate to the hydrogen peroxide solution is 1:

6.

5. The method for preparing the composite dressing according to claim 1, It is characterized in that The step 3 mixing step mainly includes the following operations: Step 3.1: Place bacterial cellulose in water and use a high-speed homogenizer to break it into a bacterial cellulose water suspension; Step 3.2: ultrasonically disperse the barium titanate hydroxylate nanoparticles in deionized water, and then mix them with the bacterial cellulose aqueous suspension under vigorous stirring in a homogenizer to ensure sufficient mixing; Step 3.3: The mixed suspension is vacuum filtered through a microporous membrane, followed by pressing and drying to form a composite cellulose membrane.

6. The method for preparing the composite dressing according to claim 5, It is characterized in that The rotation speed of the homogenizer is 1000-1500 rpm.

7. The method for preparing the composite dressing according to claim 1, It is characterized in that The mass fraction of the hydroxylated barium titanate in the bacterial cellulose is 20-100%.

8. The method for preparing the composite dressing according to claim 1, It is characterized in that The step 5 of preparing the hydrogel precursor specifically includes the following operations: Step 5.1: dissolving dopamine hydrochloride and ammonium persulfate in deionized water and stirring at room temperature for 25-30 minutes to form a polydopamine solution; Step 5.2: Add epigallocatechin-3-gallate and stir for 10-15 minutes; Step 5.3: Add acrylamide and N,N-methylenebisacrylamide and stir for 10-15 minutes. Step 5.4: Finally, add tetramethylethylenediamine and stir rapidly with a glass rod to form a hydrogel precursor.

9. The method for preparing the composite dressing according to claim 1, It is characterized in that The mass fraction of epigallocatechin-3-gallate added is 1-10%.

10. A composite fiber membrane / hydrogel composite dressing, It is characterized in that Obtained by the preparation method according to any one of claims 1 to 9.

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