Chitosan-based oxygen-releasing antibacterial sponge dressing loaded with calcium peroxide

Abstract

The invention belongs to the technical field of biomedicine, and particularly relates to a chitosan-based oxygen-releasing antibacterial sponge dressing loaded with calcium peroxide. The invention relates to a chitosan-sodium alginate-calcium peroxide composite adsorbent, which is prepared from the following components in percentage by weight: more than or equal to 80 percent of chitosan, more than or equal to 15 percent of sodium alginate and 0.5 to 3 percent of calcium peroxide. The preparation method comprises the following steps: dissolving sodium alginate in deionized water to prepare a sodium alginate solution, and dissolving chitosan in a mixed solution of acetic acid and deionized water to prepare a chitosan solution; uniformly mixing the sodium alginate solution with the chitosan solution, then adding glycerol, then adding calcium peroxide, continuously stirring, and after uniformly stirring, freezing and drying, thereby obtaining the product. The prepared sponge dressing has a porous structure, is adjustable in thickness, is convenient to carry, has breathable, antibacterial and antioxidant properties, and can be used for triggering release of oxygen by absorbing wound exudate, improving a local hypoxia microenvironment, promoting healing of diabetic wounds and relieving pain of patients.

Description

Technical Field

[0001] The invention belongs to the technical field of biomedicine, and in particular relates to a chitosan-based oxygen-releasing antibacterial sponge dressing loaded with calcium peroxide. Background Art

[0002] Diabetic wounds are common chronic wounds, and hypoxia is a key factor in delaying wound healing. Due to the high sugar environment and metabolic demand, blood circulation is hindered, resulting in insufficient oxygen supply. When skin damage occurs, vascular defects and the accumulation of high oxygen-consuming cells further aggravate tissue hypoxia. The hypoxic environment inhibits angiogenesis, re-epithelialization, and extracellular matrix synthesis. In addition, it can cause bacterial infection and persistent inflammation, which seriously delays the healing of diabetic wounds. Therefore, improving wound tissue oxygenation is the key to promoting diabetic wound healing.

[0003] In recent years, hyperbaric oxygen therapy has been widely used clinically to improve wound tissue oxygenation. However, hyperbaric oxygen therapy is usually time-limited, with each treatment lasting 1 to 2 hours. It is not possible to continuously release oxygen, and when the patient leaves the chamber, the oxygen level in the wound will drop rapidly. In addition, the diffusion of oxygen is limited by damaged blood vessels and tight tissue barriers, which leads to inefficient oxygen delivery to the wound. Therefore, it is crucial to develop an oxygen generation system that can continuously oxygenate the wound bed for a long time to accelerate healing. Local dissolved oxygen delivery is an effective method to accelerate the healing of chronic diabetic wounds.

[0004] Nowadays, various oxygen release systems based on peroxides, fluorinated molecules and microalgae have been developed to improve wound healing in hypoxic microenvironments. It is well known that perfluorinated compounds are difficult to degrade and toxic. Liquid hydrogen peroxide is decomposed and consumed in a short time, making it difficult to maintain oxygen release for a long time and may cause patient discomfort. Metal peroxides may bring excess metal ions into the circulatory system, causing systemic toxicity. Algae microorganisms may cause immune responses. Calcium peroxide (CPO), as one of the widely used oxygen sources, has the advantages of good biocompatibility, degradability, release sustainability and avoidance of excessive reaction, and has potential applications in the biomedical field. However, the materials currently used for calcium peroxide loading are mostly hydrogels, which have the disadvantages of small pore size and low permeability. Therefore, we hope to develop wound dressings that can be used for calcium peroxide loading and have good oxygen delivery efficiency. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a chitosan-based oxygen-releasing antibacterial sponge dressing loaded with calcium peroxide, which is composed of chitosan, sodium alginate and calcium peroxide, has a porous structure, adjustable thickness, is easy to carry, and has breathable, antibacterial and antioxidant properties. It can release oxygen by absorbing wound exudate, improve the local hypoxic microenvironment, promote diabetic wound healing, and relieve patients' pain.

[0006] The technical solution adopted by the present invention is as follows:

[0007] The chitosan-based oxygen-releasing antibacterial sponge dressing loaded with calcium peroxide is composed of chitosan, sodium alginate and calcium peroxide, wherein the chitosan content is ≥80%, the sodium alginate content is ≥15%, and the calcium peroxide content is 0.5% to 3%;

[0008] The preparation method comprises the following steps: dissolving sodium alginate in deionized water and stirring for 6 to 10 hours to obtain a sodium alginate solution, and dissolving chitosan in a mixture of acetic acid and deionized water and stirring for 6 to 10 hours to obtain a chitosan solution; taking the sodium alginate solution and the chitosan solution and mixing them evenly, adding glycerol, and then adding calcium peroxide, and continuing to stir for 20 minutes, and after stirring evenly, introducing into a 24-well plate, placing in a -25 to -15 DEG C refrigerator to freeze for 12 to 60 hours, and then placing in a -50 to -30 DEG C freeze dryer for freeze drying for 24 to 72 hours, so as to obtain a chitosan-based oxygen-releasing antibacterial sponge dressing loaded with calcium peroxide.

[0009] The chitosan has a deacetylation degree of 70-98% and a weight average molecular weight of 150-200 kDa.

[0010] The concentration of the sodium alginate solution is 5-10wt.%.

[0011] The concentration of the chitosan solution is 5-10wt.%; the pH value of the mixed solution of acetic acid and deionized water is 3-6.

[0012] The added amount of glycerol is 5-10wt.% of the total amount of the sodium alginate solution and the chitosan solution.

[0013] The water absorption rate of the sponge dressing is ≥1300%, and the porosity is ≥80%.

[0014] The sponge dressing has an antibacterial rate of ≥95% on Escherichia coli and Staphylococcus aureus, and a 2,2-diphenyl-1-pyridohydrazine (DPPH) clearance rate of 85-95%.

[0015] The compression deformation recovery cycle number of the sponge dressing is ≥30 times, and the continuous oxygen release can be ≥5 days.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The chitosan-based oxygen-releasing antibacterial sponge dressing loaded with calcium peroxide described in the present invention is easy to carry, and triggers the oxygen release mechanism by absorbing wound exudate, thereby not only effectively improving the local hypoxic microenvironment of diabetic wounds and promoting wound healing, but also further accelerates the healing process through its multiple properties such as breathability, antibacterial and antioxidant properties, significantly alleviating the pain of patients and providing an ideal healing-promoting environment for diabetic wounds. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is an electron microscope image (×200 times) of the sponge dressing prepared in Example 1;

[0019] Figure 2 This is an electron microscope image (×200 times) of the sponge dressing prepared in Example 2;

[0020] Figure 3 This is an electron microscope image (×200 times) of the sponge dressing prepared in Example 3;

[0021] Figure 4 This is an electron microscope image (×200 times) of the sponge dressing prepared in Comparative Example 1;

[0022] Figure 5 is the stress-strain curve of the sponge dressing prepared in Example 1;

[0023] Figure 6 is the stress-strain curve of the sponge dressing prepared in Example 2;

[0024] Figure 7 is the stress-strain curve of the sponge dressing prepared in Example 3;

[0025] Figure 8 This is the stress-strain curve of the sponge dressing prepared in Comparative Example 1. DETAILED DESCRIPTION

[0026] The present invention is further described below with reference to the embodiments, but they do not limit the implementation of the present invention.

[0027] The raw materials used in the examples and comparative examples are conventional commercially available raw materials unless otherwise specified, and the process methods used in the examples and comparative examples are conventional methods in the art unless otherwise specified.

[0028] Example 1

[0029] The chitosan-based oxygen-releasing antibacterial sponge dressing loaded with calcium peroxide is composed of chitosan, sodium alginate and calcium peroxide, wherein the content of chitosan is 82.9%, the content of sodium alginate is 16.6%, and the content of calcium peroxide is 0.5%;

[0030] The preparation method comprises the following steps: dissolving sodium alginate in deionized water and stirring for 8 hours to obtain a sodium alginate solution with a concentration of 10 wt.%, dissolving chitosan in a mixture of acetic acid and deionized water with a pH value of 5 and stirring for 8 hours to obtain a chitosan solution with a concentration of 10 wt.%, mixing the sodium alginate solution and the chitosan solution evenly, adding glycerol, and then adding calcium peroxide, and continuing to stir for 20 minutes. After stirring evenly, the mixture is introduced into a 24-well plate, placed in a refrigerator at -20±5°C for freezing for 24 hours, and then placed in a freeze dryer at -40±10°C for freeze drying for 48 hours to obtain a chitosan-based oxygen-releasing antibacterial sponge dressing loaded with calcium peroxide.

[0031] The chitosan has a deacetylation degree of 87.5±7.5% and a weight average molecular weight of 180 kDa.

[0032] The added amount of glycerol is 10wt.% of the total amount of the sodium alginate solution and the chitosan solution.

[0033] Example 2

[0034] The chitosan-based oxygen-releasing antibacterial sponge dressing loaded with calcium peroxide is composed of chitosan, sodium alginate and calcium peroxide, wherein the content of chitosan is 82.5%, the content of sodium alginate is 16.5%, and the content of calcium peroxide is 1%;

[0035] The preparation method comprises the following steps: dissolving sodium alginate in deionized water and stirring for 6 hours to obtain a sodium alginate solution with a concentration of 50 wt.%, and dissolving chitosan in a mixture of acetic acid and deionized water with a pH value of 4 and stirring for 6 hours to obtain a chitosan solution with a concentration of 5 wt.%. After mixing the sodium alginate solution and the chitosan solution evenly, glycerol is added, and then calcium peroxide is added, and stirring is continued for 20 minutes. After stirring evenly, the mixture is introduced into a 24-well plate, placed in a refrigerator at -20±5°C for freezing for 48 hours, and then placed in a freeze dryer at -40±10°C for freeze drying for 60 hours to obtain a chitosan-based oxygen-releasing antibacterial sponge dressing loaded with calcium peroxide.

[0036] The chitosan has a deacetylation degree of 87.5±7.5% and a weight average molecular weight of 180 kDa.

[0037] The added amount of glycerol is 5wt.% of the total amount of the sodium alginate solution and the chitosan solution.

[0038] Example 3

[0039] The chitosan-based oxygen-releasing antibacterial sponge dressing loaded with calcium peroxide is composed of chitosan, sodium alginate and calcium peroxide, wherein the content of chitosan is 82.1%, the content of sodium alginate is 16.4%, and the content of calcium peroxide is 1.5%;

[0040] The preparation method comprises the following steps: dissolving sodium alginate in deionized water and stirring for 7 hours to obtain a sodium alginate solution with a concentration of 6wt.%, dissolving chitosan in a mixture of acetic acid and deionized water with a pH value of 6 and stirring for 7 hours to obtain a chitosan solution with a concentration of 6wt.%, mixing the sodium alginate solution and the chitosan solution evenly, adding glycerol, and then adding calcium peroxide, and continuing to stir for 20 minutes. After stirring evenly, the mixture is introduced into a 24-well plate, placed in a refrigerator at -20±5°C for freezing for 36 hours, and then placed in a freeze dryer at -40±10°C for freeze drying for 48 hours to obtain a chitosan-based oxygen-releasing antibacterial sponge dressing loaded with calcium peroxide.

[0041] The chitosan has a deacetylation degree of 87.5±7.5% and a weight average molecular weight of 180 kDa.

[0042] The added amount of glycerol is 8wt.% of the total amount of the sodium alginate solution and the chitosan solution.

[0043] Comparative Example 1

[0044] The difference from Example 3 is that the sponge dressing is composed of chitosan and sodium alginate, wherein the content of chitosan is 83.3% and the content of sodium alginate is 16.7%. The rest is the same as Example 3.

[0045] The sponge dressings prepared in Examples 1 to 3 and Comparative Example 1 were tested for performance, and the testing methods were as follows:

[0046] The surface morphologies of the sponge dressings prepared in Examples 1 to 3 and Comparative Example 1 were observed using a scanning electron microscope. Figures 1 to 4 As shown by Figures 1 to 4 It can be seen that the prepared sponge dressing is continuous and porous, and has an irregular structure, and its pores are interconnected.

[0047] The mechanical properties of the sponge dressings prepared in Examples 1 to 3 and Comparative Example 1 were tested using a universal material testing machine (Instron 3382). The samples were compressed 30 times at a speed of 100 mm / min. The samples were cut into cylinders with a diameter of 14 mm and a height of 10 mm. The same sample was tested three times in parallel. The test results are shown in FIG. Figures 5 to 8 As shown by Figures 5 to 8 It can be seen that the prepared sponge dressing has good flexibility and shape recovery, which helps the sponge to fit the wound surface and reduce damage. Good compressive resilience enables the sponge to maintain its pore structure under external pressure, providing a three-dimensional dynamic microenvironment that can effectively regulate cell behavior.

[0048] Dissolved oxygen content (mg / L): A dissolved oxygen meter (JPSJ-606L, Shanghai Precision Scientific Instrument Co., Ltd.) was used to test the dissolved oxygen content of the sponge dressings prepared in Examples 1 to 3 and Comparative Example 1. 5 mL of deionized water was added to a 50 mL sample bottle. The sample size was a cylinder with a diameter of 14 mm and a height of 10 mm. After inserting the oxygen electrode probe, the sample bottle was sealed with a sealing film. After the readings stabilized, the dissolved oxygen content was recorded. The test results are shown in Table 1.

[0049] Porosity (%): The sponge dressings prepared in Examples 1 to 3 and Comparative Example 1 were cut into round pieces with a diameter of 14 mm. The porosity of the sponge dressings after saturation in ethanol was determined by the immersion method. The samples were weighed before and after immersion in ethanol, and the test was repeated three times in parallel. The porosity was calculated by the following formula:

[0050]

[0051] Wherein, W2 is the weight after saturation, W1 is the initial weight, ρ is the density of ethanol, and V is the volume of the sponge dressing. The test results are shown in Table 1.

[0052] Antibacterial rate (%): The antibacterial properties of the sponge dressings prepared in Examples 1 to 3 and Comparative Example 1 were tested with reference to AATCC100-2012. The test results are shown in Table 1.

[0053] Table 1 Performance test results

[0054]

[0055] As can be seen from Table 1, the sponge dressing prepared by the present invention has an increased dissolved oxygen content and porosity with an increase in the proportion of calcium peroxide, which can effectively stimulate epithelial tissue formation, collagen synthesis and angiogenesis. In Comparative Example 1, since calcium peroxide is not contained, local hypoxia in diabetic wounds will inhibit angiogenesis, re-epithelialization and extracellular matrix synthesis to interfere with the wound healing process. The calcium peroxide loaded in the embodiment can absorb wound exudate to react and generate hydrogen peroxide, continuously release oxygen, and improve the local hypoxic microenvironment. In addition, the sponge dressing prepared by the present invention has good antibacterial properties, and the chitosan content in the sponge dressing is relatively high, and the antibacterial rates of Escherichia coli and Staphylococcus aureus reach 99.99%. In addition, the generated hydrogen peroxide can synergistically act with chitosan to effectively avoid wound infection and promote wound healing.

Claims

1. A chitosan-based oxygen-releasing antibacterial sponge dressing loaded with calcium peroxide, characterized in that: It is composed of chitosan, sodium alginate and calcium peroxide, wherein the content of chitosan is ≥80%, the content of sodium alginate is ≥15%, and the content of calcium peroxide is 0.5% to 3%; The preparation method comprises the following steps: dissolving sodium alginate in deionized water to obtain a sodium alginate solution, and dissolving chitosan in a mixture of acetic acid and deionized water to obtain a chitosan solution; mixing the sodium alginate solution and the chitosan solution evenly, adding glycerol, and then adding calcium peroxide, continuing to stir, stirring evenly, freezing, and drying to obtain a chitosan-based oxygen-releasing antibacterial sponge dressing loaded with calcium peroxide.

2. The calcium peroxide-loaded chitosan-based oxygen-releasing antibacterial sponge dressing according to claim 1, characterized in that: The chitosan has a deacetylation degree of 70-98% and a weight average molecular weight of 150-200 kDa.

3. The calcium peroxide-loaded chitosan-based oxygen-releasing antibacterial sponge dressing according to claim 1, characterized in that: The concentration of the sodium alginate solution is 5-10wt.%.

4. The calcium peroxide-loaded chitosan-based oxygen-releasing antibacterial sponge dressing according to claim 1, characterized in that: The concentration of the chitosan solution is 5-10wt.%; the pH value of the mixed solution of acetic acid and deionized water is 3-6.

5. The calcium peroxide-loaded chitosan-based oxygen-releasing antibacterial sponge dressing according to claim 1, characterized in that: The added amount of glycerol is 5-10wt.% of the total amount of the sodium alginate solution and the chitosan solution.

6. The calcium peroxide-loaded chitosan-based oxygen-releasing antibacterial sponge dressing according to claim 1, characterized in that: The freezing temperature is -25 to -15°C and the freezing time is 12 to 60 hours.

7. The calcium peroxide-loaded chitosan-based oxygen-releasing antibacterial sponge dressing according to claim 1, characterized in that: The drying is freeze drying, the freeze drying temperature is -50 to -30°C, and the time is 24 to 72 hours.

8. The calcium peroxide-loaded chitosan-based oxygen-releasing antibacterial sponge dressing according to claim 1, characterized in that: The water absorption rate of the sponge dressing is ≥1300%, and the porosity is ≥80%.

9. The calcium peroxide-loaded chitosan-based oxygen-releasing antibacterial sponge dressing according to claim 1, characterized in that: The sponge dressing has an antibacterial rate of ≥95% on Escherichia coli and Staphylococcus aureus, and a 2,2-diphenyl-1-pyridohydrazine clearance rate of 85-95%.

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