Micro-current sponge dressing for promoting healing of pressure sores and application of micro-current sponge dressing

Abstract

The invention belongs to the technical field of medical dressings, and particularly relates to a micro-current sponge dressing for promoting healing of pressure sores and application of the micro-current sponge dressing. The device comprises a diaphragm, a cathode sponge and an anode sponge, the cathode sponge is annularly wrapped outside the diaphragm; and the anode sponge is distributed in the diaphragm in a cylindrical shape. According to the micro-current sponge dressing provided by the invention, the cathode sponge and the anode sponge generate an oxidation-reduction reaction in wound exudate to generate current; the micro-current can promote collagen regeneration, can generate zinc metal ions with an antibacterial effect, and can reduce the wound infection risk and promote wound healing; besides, the micro-current sponge dressing has a three-dimensional porous structure, has excellent water absorption performance, can fully absorb wound exudate, also has good elasticity, can provide a buffer layer between a patient and a supporting surface to relieve wound surface pressure, and finally promotes healing of a pressure sore wound surface.

Description

Technical Field

[0001] This application belongs to the technical field of medical dressings, and specifically relates to a microcurrent sponge dressing for promoting pressure ulcer healing and its application. Background Art

[0002] The condition of pressure ulcers is relatively complex, with slow self-repair, severe tissue necrosis, and easy repeated infections, which can then develop into chronic wounds. In addition, chronic wounds will in turn exacerbate the primary disease, which not only causes great physical and psychological pressure on patients, but also brings a heavy burden to families and society. The pathogenesis of pressure ulcers is very complex, involving many disciplinary fields, and multiple factors interact with each other. For example, local tissue hypoxia, wound bacterial infection, ischemia-reperfusion injury, etc. Although there are many factors, tissue ischemia caused by mechanical force is widely considered to be the initiating factor. Common dressings currently used in the market for treating pressure ulcers include foam dressings, hydrogel dressings, hydrocolloid dressings, transparent films, alginate dressings, etc. These dressings have single functions and are difficult to meet the needs of complex wound healing.

[0003] Studies have shown that microcurrent has antibacterial, anti-inflammatory, cell migration guidance, and collagen regeneration promotion effects during wound healing; currently, microcurrent dressings used for wound healing, such as PED-10 electronic dressings and Posifect (Biofisica) dressings, require an external power supply, and the portability of the dressings cannot be guaranteed; at the same time, dressings for pressure ulcers should have elasticity to provide a buffer layer between the patient and the support surface to relieve the wound pressure, and ultimately promote the healing of pressure ulcer wounds. Summary of the Invention

[0004] The technical problem to be solved by the present invention is: to provide a microcurrent sponge dressing that is convenient to use, does not require external power supply, can generate microcurrent by itself, and presents a three-dimensional porous structure and has good elasticity to relieve the pressure of pressure ulcer wounds.

[0005] The present invention provides a microcurrent sponge dressing for promoting pressure ulcer healing and its application, and specifically adopts the following technical solutions: In the first aspect, a microcurrent sponge dressing for promoting pressure ulcer healing, which includes a cathode sponge, an anode sponge, and a diaphragm; the cathode sponge is annularly wrapped outside the diaphragm; the anode sponge is cylindrically distributed inside the diaphragm; The preparation methods of the cathode sponge and the anode sponge specifically include the following steps: Add carboxymethyl chitosan to a phosphate buffer solution and stir to obtain a chitosan dispersion; Mix the chitosan dispersion and a bacterial cellulose solution to obtain dispersion A; Place the silane coupling agent in the dispersion liquid A, stir evenly to obtain dispersion liquid B, then add titanium powder or zinc powder, and then place it in a mold, freeze, freeze-dry, and vacuum-dry to obtain the anode sponge and the cathode sponge respectively; The preparation method of the diaphragm includes the following steps: Coat a layer of acrylic emulsion on the upper surface and side surface of the anode sponge, and vacuum-dry to obtain the diaphragm.

[0006] As a further preferred embodiment, the mass ratio of the carboxymethyl chitosan, phosphate buffer solution, bacterial cellulose solution, and silane coupling agent is 1:57:40:2.

[0007] As a further preferred embodiment, the solid content in the bacterial cellulose solution is 0.8%.

[0008] As a further preferred embodiment, the silane coupling agent includes one or more of KH550, KH560, and KH570.

[0009] As a further preferred embodiment, the pH of the phosphate buffer solution is 7.5 - 9.0.

[0010] As a further preferred embodiment, the temperature for stirring the carboxymethyl chitosan dispersed in the phosphate buffer solution is 40 °C - 60 °C.

[0011] In the second aspect, the present invention also provides the application of the above microcurrent sponge dressing in the preparation of an antibacterial material for promoting wound healing.

[0012] As a further preferred embodiment, the wound includes a pressure ulcer wound surface.

[0013] In the third aspect, the present invention also provides an antibacterial material for pressure ulcer wound surface healing, and the antibacterial material includes the above microcurrent sponge dressing.

[0014] The beneficial effects of the present invention are: The present invention provides a microcurrent sponge dressing, which includes a diaphragm, a cathode sponge, and an anode sponge. The cathode sponge is annularly wrapped outside the diaphragm, and the anode sponge is cylindrically distributed inside the diaphragm. The cathode sponge and the anode sponge generate a redox reaction in the wound exudate to produce an electric current. According to the data results of the embodiments of the present invention, simulating the humid environment of the wound can release a voltage greater than 0.2V. This microcurrent can promote collagen regeneration, and at the same time, zinc metal ions with antibacterial effects can be generated, which can reduce the risk of wound infection and promote wound healing. In addition, the microcurrent sponge dressing has a three-dimensional porous structure and excellent water absorption performance, can fully absorb wound exudate, maintain a moist wound healing environment, and accelerate wound surface healing. It also has good resilience performance, can provide a buffer layer between the patient and the support surface to reduce the wound surface pressure, relieve the inflammatory damage caused by ischemia and hypoxia of the skin due to long-term pressure in patients with pressure sores, and ultimately promote the healing of pressure sore wounds. Description of the Drawings

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0016] Figure 1 The figure shows the CCK-8 cytotoxicity test results of the microcurrent sponge dressings prepared in Examples 1-3; Figure 2 The figure shows the results of the cell viability and death staining test of the microcurrent sponge dressings prepared in Examples 1-3; Figure 3 The figure shows the antibacterial results of the microcurrent sponge dressings prepared in Examples 1-3; Figure 4 The figure shows the SEM and EDS characterization diagrams of the microcurrent sponge dressings prepared in Examples 1-3; Figure 5 The figure shows the voltage and current change diagrams of the microcurrent sponge dressings prepared in Examples 1-3; Figure 6 The figure shows the water absorption rate results of the microcurrent sponge dressings prepared in Examples 1-3; Figure 7 The figure shows the stress-strain curve diagrams of the microcurrent sponge dressings prepared in Examples 1-3; Figure 8 The figure shows the physical picture of the microcurrent sponge dressing prepared in Example 1 after being moistened. Detailed Embodiments

[0017] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts belong to the scope of protection of the present application.

[0018] Embodiment 1 A microcurrent sponge dressing for promoting pressure ulcer healing, and its preparation method specifically includes the following steps: (1) Preparation of columnar anode sponge and diaphragm: Step 1: Add 1 g of carboxymethyl chitosan to 57 g of phosphate buffer solution with pH = 8, stir well for 2 hours, and the temperature during stirring is 45 °C to prepare a chitosan dispersion; Step 2: Add 40 g of bacterial cellulose dispersion with a solid content of 0.8% to the chitosan dispersion in Step 1, stir for 30 minutes to prepare Dispersion A, and then add 2 g of silane coupling agent KH560 to Dispersion A and stir for 30 minutes to obtain Dispersion B; Step 3: Add 0.5 g of titanium powder to Dispersion B in Step 2, stir well for 10 hours, then inject it into a circular mold, place it in a -40 °C refrigerator and freeze for 8 hours, then put it into a freeze dryer and freeze-dry for 24 hours, and then vacuum-dry at 110 °C for 50 minutes to obtain an anode sponge. Then, coat a layer of acrylic emulsion on the upper surface and side of the sponge and vacuum-dry for 24 hours to form an anode sponge diaphragm, that is, the BCK@Ti 0.5 sponge.

[0019] (2) Preparation of annular cathode sponge: Step 1: Add 1 g of carboxymethyl chitosan to 57 g of phosphate buffer solution with pH = 8, stir well for 2 hours, and the temperature during stirring is 45 °C to prepare a chitosan dispersion; Step 2: Add 40 g of bacterial cellulose dispersion with a solid content of 0.8% to the chitosan dispersion described in step (1), stir for 30 minutes to prepare Dispersion A, and then add 2 g of silane coupling agent KH560 to Dispersion A and stir for 30 minutes to obtain Dispersion B; Step 3: Add 0.5 g of zinc powder to Dispersion B in Step 2, stir well for 10 hours, then inject it into an annular mold, place it in a -40 °C refrigerator and freeze for 8 hours, then put it into a freeze dryer and freeze-dry for 24 hours, and then vacuum-dry at 110 °C for 50 minutes to obtain a cathode sponge, that is, BCK@Zn 0.5 sponge; (3) Preparation of microcurrent sponge dressing: The microcurrent sponge dressing is obtained by nesting the anode sponge coated with the diaphragm into the cathode sponge, i.e., BCK@Ti / Zn 0.5 sponge.

[0020] The physical picture of the microcurrent sponge dressing prepared in this invention after being moistened is as Figure 8 shown (where 1, cathode sponge; 2, upper surface diaphragm; 3, anode sponge; 4, side surface diaphragm). When the sponge is used to treat pressure ulcer wounds, it can fully absorb the exudate from the wound. The anode sponge (titanium electrode) and the cathode sponge (zinc electrode) form a circuit in a humid environment and an electrochemical reaction occurs. The electrochemical reaction of the zinc electrode is: . At the titanium electrode, the reaction formula is: . The content of zinc in the human body ranks second only to iron. About 20% of the zinc in the adult body exists in the skin. It is one of the most important trace elements in the human body. As a coenzyme factor and the active center of proteins, zinc is essential for many enzymes and macromolecules. The direct effect of zinc ions on wound repair is mainly to promote the proliferation of repair cells and protein synthesis through zinc-dependent enzymes (such as DNA polymerase, RNA polymerase), thereby promoting wound healing.

[0021] Example 2 A microcurrent sponge dressing for promoting the healing of pressure ulcers, and its preparation method specifically includes the following steps: (1) Preparation of columnar anode sponge and diaphragm: Step 1: Add 1 g of carboxymethyl chitosan to 57 g of phosphate buffer solution with a pH of 8, stir well for 2 hours at a temperature of 45 °C to prepare a chitosan dispersion; Step 2: Add 40 g of bacterial cellulose dispersion with a solid content of 0.8% to the chitosan dispersion described in Step 1, stir for 30 minutes to prepare dispersion A, and then add 2 g of silane coupling agent KH560 to dispersion A and stir for 30 minutes to obtain dispersion B; Step 3: Add 1 g of titanium powder to the dispersion B described in Step 2, stir well for 10 hours, then inject it into a circular mold, place it in a -40 °C refrigerator and freeze for 8 hours, then put it into a freeze dryer for freeze drying for 24 hours, and then vacuum dry at 110 °C for 50 minutes to obtain the anode sponge. Then, coat a layer of acrylic emulsion on the upper surface and side surface of the sponge and vacuum dry for 24 hours to form the anode sponge diaphragm, i.e., obtain BCK@Ti 1 sponge.

[0022] (2) Preparation of annular cathode sponge: Step 1: Add 1 g of carboxymethyl chitosan to 57 g of phosphate buffer solution with a pH of 8, stir well for 2 hours at a temperature of 45 °C to prepare a chitosan dispersion; Step 2: Add 40 g of bacterial cellulose dispersion with a solid content of 0.8% to the chitosan dispersion described in step (1), stir for 30 minutes to prepare dispersion A, and then add 2 g of silane coupling agent KH560 to dispersion A and stir for 30 minutes to obtain dispersion B; Step 3: Add 1 g of zinc powder to the dispersion B described in step 2, stir thoroughly for 10 hours, then inject it into a ring mold, place it in a -40 °C refrigerator and freeze for 8 hours, then place it in a freeze dryer and freeze-dry for 24 hours, and then vacuum-dry at 110 °C for 50 minutes to obtain a cathode sponge, namely BCK@Zn 1 sponge.

[0023] (3) Preparation of microcurrent sponge dressing: Nest the anode sponge coated with the separator into the cathode sponge to obtain the microcurrent sponge dressing, namely BCK@Ti / Zn 1 sponge.

[0024] Example 3 A microcurrent sponge dressing for micro-promoting pressure ulcer healing, and its preparation method specifically includes the following steps: (1) Preparation of columnar anode sponge and separator: Step 1: Add 1 g of carboxymethyl chitosan to 57 g of phosphate buffer solution with PH = 8, stir thoroughly for 2 hours, and the temperature during stirring is 45 °C to prepare a chitosan dispersion; Step 2: Add 40 g of bacterial cellulose dispersion with a solid content of 0.8% to the chitosan dispersion described in step (1), stir for 30 minutes to prepare dispersion A, and then add 2 g of silane coupling agent KH560 to dispersion A and stir for 30 minutes to obtain dispersion B; Step 3: Add 2 g of titanium powder to the dispersion B described in step 2, stir thoroughly for 10 hours, then inject it into a circular mold, place it in a -40 °C refrigerator and freeze for 8 hours, then place it in a freeze dryer and freeze-dry for 24 hours, and then vacuum-dry at 110 °C for 50 minutes to obtain an anode sponge, and then coat a layer of acrylic emulsion on the upper surface and side of the sponge and vacuum-dry for 24 hours to form an anode sponge separator, namely BCK@Ti 2 sponge.

[0025] (2) Preparation of ring-shaped cathode sponge: Step 1: Add 1 g of carboxymethyl chitosan to 57 g of phosphate buffer solution with PH = 8, stir thoroughly for 2 hours, and the temperature during stirring is 45 °C to prepare a chitosan dispersion; Step 2: Add 40 g of bacterial cellulose dispersion with a solid content of 0.8% to the chitosan dispersion described in step (1), stir for 30 minutes to prepare dispersion A, and then add 2 g of silane coupling agent KH560 to dispersion A and stir for 30 minutes to obtain dispersion B; Step 3: Add 2 g of zinc powder to the dispersion B described in step 2, stir well for 10 hours, then inject it into a ring mold, place it in a -40 °C refrigerator for 8 hours, and then place it in a freeze dryer for freeze drying for 24 hours, and then vacuum dry at 110 °C for 50 minutes to obtain a cathode sponge, namely BCK@Zn 2 sponge.

[0026] (3) Preparation of microcurrent sponge dressing: Nest the anode sponge diaphragm into the cathode sponge to obtain the microcurrent sponge dressing, namely BCK@Ti / Zn 2 sponge.

[0027] Characterization tests were carried out on the cross-section of the above-prepared microcurrent sponge dressing, and the SEM and EDS characterization results are as Figure 4 shown, where Figure 4 (a) in is the SEM and EDS diagrams of BCK@Zn 0.5 , BCK@Zn 1 and BCK@Zn 2 ; Figure 4 (b) in is the SEM and EDS diagrams of BCK@Ti 0.5 , BCK@Ti 1 and BCK@Ti 2 ; It can be seen from (a) in Figure 4 and Figure 4 (b) in that the sponge has a porous structure, and EDS shows the distribution of zinc element in the cathode sponge and the distribution of titanium element in the anode sponge; Figure 4 (c) in is the SEM diagram of BCK@Ti 0.5 at 300 μm. It can be seen from Figure 4 (c) in that the microcurrent sponge has a three-dimensional porous structure and is easy to absorb liquid.

[0028] Example 4 The microcurrent sponge dressing prepared in the above example was used for CCK-8 cytotoxicity test, and the specific process is as follows: Use L929 fibroblasts for CCK-8 experiment to evaluate the in vitro biocompatibility of the microcurrent. First, culture the cells in a medium containing 10% fetal bovine serum and 1% penicillin streptomycin; place the medium in an incubator at 37 °C, containing 5% CO 2 and 100% humidity. Place 5×10 3L929 fibroblasts were cultured overnight to allow the cells to adhere to the wall; then, the sponge extracts (0.01 g / mL) of different groups (the microcurrent sponge dressings prepared in Examples 1-3) were added to each well for co-culture. The group without extract was used as a blank control. After incubating for 1 day, 3 days, and 7 days respectively, 10 μL of CCK-8 reagent was added to the culture medium and incubated for another 1 h. Finally, 100 μL of the culture solution was aspirated from the wells into a new 96-well plate, and the absorbance at 450 nm was measured using a microplate reader.

[0029] The results are as Figure 1 shown. It can be seen from the results that the microcurrent sponge dressing has no obvious cytotoxicity and exhibits good biocompatibility.

[0030] Example 5 Cell viability and cytotoxicity staining experiment The biocompatibility of the hydrogel was evaluated by live / dead staining. L929 fibroblasts were co-cultured with the sponge extracts of different groups (the microcurrent sponge dressings prepared in Examples 1-3) for 1 day, 3 days, and 7 days. The group without extract was used as a blank control. Live cells were stained with Calcein-AM to detect green fluorescence, and dead cells were stained with PI to detect red fluorescence. Confocal laser scanning microscopy was used to obtain the fluorescence images of L929 cells.

[0031] The results are as Figure 2 shown. It can be seen from the results that during the co-culture for 1 day, 3 days, and 7 days, the cells under different treatments increased significantly and showed green fluorescence, indicating that the microcurrent sponge dressing has good biocompatibility.

[0032] Example 6 The microcurrent sponge dressings prepared in the above examples were tested for antibacterial activity. The specific process is as follows: The samples of different groups (the microcurrent sponge dressings prepared in Examples 1-3) after ultraviolet sterilization treatment were washed three times with PBS and placed in a 12-well plate. The control group did not add the dressing. 1 mL of 10 8 CFU / mL of bacterial solution was added to each well and co-cultured for 18-24 hours. 50 μL of the bacterial solution was taken and spread on an agar plate at an appropriate dilution factor, and incubated at 37 °C for 18-24 hours. The number of colonies was counted. Each group of samples was tested in triplicate and the average value was taken.

[0033] The results are as Figure 3 shown. It can be seen from the results that the average colony numbers of the experimental group (denoted as B) and the control group (denoted as A) were statistically analyzed, and the antibacterial rate (%) = (A - B) / A × 100% was calculated. The results showed that BCK@Ti / Zn 0.5 、BCK@Ti / Zn 1, BCK@Ti / Zn 2 The antibacterial rates of the dressing against Staphylococcus aureus were 97.6%, 99.4%, and 99.8% respectively, the antibacterial rates against methicillin-resistant Staphylococcus aureus were 97.9%, 99.7%, and 100% respectively, and the antibacterial rates against Escherichia coli were 51.1%, 52.4%, and 69.6% respectively. It was proved that the microcurrent sponge dressing had strong antibacterial ability against Staphylococcus aureus and methicillin-resistant Staphylococcus aureus, and had relatively strong antibacterial ability against Escherichia coli, thus preventing and reducing the infection of the wound surface and promoting wound healing.

[0034] Example 7 The voltage of the microcurrent sponge dressing prepared in the above example was measured, and the specific process was as follows: The sponge dressings of different groups were fully moistened with phosphate buffer solution (simulating the moist environment of the wound), and the voltage and current on the 0th day and the 3rd day were measured using a multimeter respectively.

[0035] The results were as Figure 5 shown, and it could be seen from the results that the sponge dressing could continuously generate voltage and current for more than 3 days without an external energy source.

[0036] Example 8 The water absorption rate of the microcurrent sponge dressing prepared in the above example was measured, and the specific process was as follows: At room temperature, the sponge was placed in water for a period of time to fully absorb, and then taken out and weighed. The calculation formula for the water absorption rate was: water absorption rate = (W1 - W0) / W0 × 100%, where W0 and W1 were the masses of the sample before and after immersion respectively.

[0037] The results were as Figure 6 shown, and it could be seen from the results that the sponge showed excellent liquid absorption ability, which was beneficial to accelerating the absorption of wound exudate, maintaining the moist healing environment of the wound, and accelerating wound healing.

[0038] Example 9 The microcurrent sponge dressing prepared in the above example was subjected to a cyclic compression experiment, and the specific process was as follows: The mechanical properties of the sponge were evaluated by a cyclic compression test using a universal testing machine at room temperature. The cyclic compression test was carried out after the sponge was fully wetted. First, it was compressed to a preset strain of 50% at a speed of 2 mm / min, and then recovered to 0% strain at the same speed for 5 cycles.

[0039] The stress-strain curve was as Figure 7 shown, Figure 7 in which (a) was the stress-strain curve of the first compression cycle in the 5-time compression cycle experiment of the microcurrent sponge dressing prepared in Examples 1 - 3, Figure 7Among them, (b) is the stress-strain curve of the microcurrent sponge dressing prepared in Example 2 for 5 consecutive compression cycle experiments. From Figure 7 it can be seen that the sponge has good mechanical properties. After five compressions, the mechanical properties are stable, indicating that it has excellent resilience, which can reduce skin stress and relieve the inflammatory damage caused by ischemia and hypoxia of the skin of pressure ulcer patients due to long-term pressure, thus promoting the healing of pressure ulcer wounds.

[0040] The embodiments of the present application have been described above in conjunction with the accompanying drawings. Specific examples have been used herein to elaborate on the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the core idea of the present application. However, the present application is not limited to the above specific implementation manners. The above specific implementation manners are only illustrative and not restrictive. Under the inspiration of the present application, those of ordinary skill in the art can also make many forms without departing from the purpose of the present application and the scope protected by the claims, all of which belong to the protection scope of the present application.

Claims

1. A microcurrent sponge dressing for promoting the healing of pressure sores, characterized in that: It includes a cathode sponge, an anode sponge and a diaphragm; the cathode sponge is annularly wrapped outside the diaphragm; the anode sponge is cylindrically distributed inside the diaphragm; The method for preparing the cathode sponge and the anode sponge specifically comprises the following steps: adding carboxymethyl chitosan into a phosphate buffer solution and stirring to obtain a chitosan dispersion; The chitosan dispersion and the bacterial cellulose solution are mixed to obtain a dispersion A; The silane coupling agent is placed in the dispersion A, stirred evenly to obtain the dispersion B, and then titanium powder or zinc powder is added, and then placed in a mold, frozen, freeze-dried, and vacuum-dried to obtain the anode sponge and cathode sponge respectively; The method for preparing the diaphragm comprises the following steps: A layer of acrylic emulsion is coated on the upper surface and side surfaces of the anode sponge and vacuum dried to obtain the separator.

2. The microcurrent sponge dressing according to claim 1, characterized in that: The mass ratio of the carboxymethyl chitosan, the phosphate buffer solution, the bacterial cellulose solution and the silane coupling agent is 1:57:40:

2.

3. The microcurrent sponge dressing according to claim 2, characterized in that: The solid content of the bacterial cellulose solution is 0.8%.

4. The microcurrent sponge dressing according to claim 1, characterized in that: The mass ratio of dispersion B to titanium powder or zinc powder is 100:0.25-2.

5.

5. The microcurrent sponge dressing according to claim 1, characterized in that: The silane coupling agent includes one or more of KH550, KH560 and KH570.

6. The microcurrent sponge dressing according to claim 1, characterized in that: The pH of the phosphate buffer solution is 7.5-9.

0.

7. The microcurrent sponge dressing according to claim 1, characterized in that: The temperature for stirring the carboxymethyl chitosan in the phosphate buffer solution is 40°C-60°C.

8. Use of the microcurrent sponge dressing according to any one of claims 1 to 7 in the preparation of an antibacterial material for promoting wound healing.

9. The use according to claim 8, characterized in that: The wound includes a pressure ulcer wound.

10. An antibacterial material for healing of pressure sore wounds, characterized in that: The invention comprises the microcurrent sponge dressing according to any one of claims 1 to 7.

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