Improved hydrogel dressing for treating diabetic wound based on photodynamic therapy and preparation method thereof

Abstract

The invention discloses an improved diabetes wound treatment hydrogel dressing based on photodynamic therapy and a preparation method, and relates to the technical field of hydrogel dressings, and the key point of the technical scheme is that a photosensitizer, an antibacterial nano material and bioactive molecules are combined for use through a layered structure. According to the invention, each layer can exert a specific treatment effect obviously, so that the overall treatment effect is enhanced, the wound healing efficiency is greatly improved, and the infection risk is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of hydrogel dressings, and more specifically to an improved hydrogel dressing for treating diabetic wounds based on photodynamic therapy and a preparation method thereof. Background Art

[0002] With the extension of human life span and the improvement of living standards, the incidence of diabetes has increased year by year, and the incidence of type II diabetes has shown a trend of younger age. Clinically, diabetic patients have a disordered immune system and a weakened ability to resist bacterial infection, making them more susceptible to infection at all sites of injury. Since the skin wounds of diabetic patients are characterized by moisture and high sugar content, which provides a good place for the growth of bacteria, the infection problem of skin wounds is the most serious and is one of the important factors inducing diabetic foot. Neutrophils are one of the most important immune cells to resist infection in the early stages of inflammation. However, due to the long-term systemic chronic inflammation induced by hyperglycemia, diabetic patients are under long-term pressure on neutrophils, which often have major functional defects and cannot exert their due immune function. Compared with ordinary infected wounds, the microenvironment of diabetic infected wounds is more complex. In addition to the oxidative stress caused by high levels of reactive oxygen species, it is also accompanied by diabetes-specific high expression of proinflammatory factors (such as tumor necrosis factor-α, interleukin-1β, interleukin-6, etc.), hypoxia, malnutrition, and blocked nitric oxide synthesis. The healing of skin wounds includes four processes: hemostasis, inflammation, proliferation and remodeling. The slow inflammatory process hinders the normal transition from the inflammatory phase to the subsequent proliferation and remodeling phases, further inducing the formation of chronic wounds that are difficult to heal.

[0003] More and more studies have shown that hydrogels can alleviate the development of inflammation by regulating the level of reactive oxygen in the wound surface. They are the most ideal and most promising dressings for caring for diabetic patients’ wounds. However, the hydrogels currently on the market have the following problems in treating diabetic wounds:

[0004] 1. Limited therapeutic effect: Existing photodynamic hydrogels often only focus on the photodynamic effect of photosensitizers when treating diabetic wounds, lack multiple treatment mechanisms, and lead to low healing efficiency;

[0005] 2. High risk of infection: Traditional hydrogels usually do not have antibacterial properties in wound treatment, which can easily lead to wound infection and increase the risk of complications for patients;

[0006] 3. Lack of personalization: Existing technologies lack flexibility in treatment plans and cannot be adjusted according to changes in wound conditions, limiting the treatment effect;

[0007] 4. Uneven drug release: The drug release of traditional hydrogels often cannot be precisely controlled, which may affect healthy tissues and affect the treatment effect. Summary of the invention

[0008] The purpose of the present invention is to provide an improved hydrogel dressing for treating diabetic wounds based on photodynamic therapy and a preparation method thereof, so as to solve the above-mentioned problems.

[0009] The above technical objectives of the present invention are achieved through the following technical solutions: A method for preparing an improved hydrogel dressing for treating diabetic wounds based on photodynamic therapy, comprising the following steps:

[0010] S1. Dissolve the base layer material:

[0011] S1.1 Photosensitive layer: In a container, add solvent, weigh sodium alginate and aminophthalocyanine, and stir with a stirrer to ensure that the sodium alginate is completely dissolved to form a uniform colloidal solution;

[0012] S1.2 Antibacterial layer, in another container, weigh sodium alginate and copper-based nanoparticles, add solvent, and stir evenly with a stirrer to ensure that all ingredients are fully mixed to form a colloidal solution, wherein the mass ratio of sodium alginate to copper-based nanoparticles is 140:1, and the mass volume ratio of sodium alginate to solvent is 70:27 g / ml;

[0013] S1.3 Active molecule layer: In a separate container, weigh sodium alginate and

[0014] miR-142-3p, add solvent, stir evenly with a stirrer, and ensure

[0015] miR-142-3p was completely dispersed in the solution;

[0016] S2. Forming a layered structure: pouring the colloidal solution of the photosensitizer layer into a pre-prepared mold, leaving it to stand at room temperature until it is partially solidified, so as to form a preliminarily solidified layer; then adding the antibacterial layer, slowly pouring the colloidal solution of the antibacterial layer onto the base layer to ensure good contact between the two layers, leaving it to stand again until it is partially solidified; finally adding the bioactive molecule layer, gently pouring the mixture of the bioactive molecule layer onto the antibacterial layer to form a third layer, and leaving it to stand to solidify;

[0017] S3. Cross-linking treatment: After the last layer in step S2 is cured, calcium chloride solution is added to promote cross-linking of the entire structure so that each layer is firmly bonded; continue to stand for several minutes to ensure that all layers are evenly cross-linked;

[0018] S4. Post-processing: The entire layered hydrogel is removed from the mold, washed with PBS or saline to remove unreacted components, and then dried or freeze-dried;

[0019] S5. Storage: The synthesized layered hydrogel was placed in a sealed container and stored at low temperature to maintain the stability of its active ingredients.

[0020] The present invention is further configured as follows: in step S1.1, the mass ratio of sodium alginate to aminophthalocyanine is 35:1, and the mass volume ratio of sodium alginate to solvent is 70:27 g / ml.

[0021] The present invention is further configured as follows: in step S1.3, the mass ratio of sodium alginate to miR-142-3p is 7000:1, and the mass volume ratio of sodium alginate to solvent is 70:27 g / ml.

[0022] The present invention is further configured as follows: in step S1, the solvent is physiological saline or PBS.

[0023] The present invention is further configured as follows: in step S2, the thicknesses of the photosensitizer layer, the antibacterial layer and the active molecule layer are all 1-2 mm.

[0024] The present invention is further configured as follows: in step S3, the concentration of the calcium chloride solution is 0.5 mol / L.

[0025] The present invention also provides an improved hydrogel dressing for treating diabetic wounds based on photodynamic therapy, which is prepared by the above-mentioned method for preparing the improved hydrogel dressing for treating diabetic wounds based on photodynamic therapy.

[0026] In summary, the present invention has the following beneficial effects:

[0027] 1. Hierarchical structure design

[0028] Multifunctional layers: The photosensitizer, antimicrobial nanomaterials and bioactive molecules are isolated separately through a layered structure, so that each layer can play a specific therapeutic role, enhancing the overall therapeutic effect.

[0029] 2. Precision drug release

[0030] Gradient release mechanism: Different levels of drug ingredients can be designed to be released in stages, achieving more precise drug control and thus improving the therapeutic effect.

[0031] 3. Material innovation

[0032] Use of composite materials: Combining sodium alginate, aminophthalocyanine and copper-based nanoparticles, the antibacterial property and photodynamic therapy effect of the hydrogel are improved.

[0033] 4. Intelligent response function

[0034] Smart materials: Use pH-sensitive materials to automatically adjust physical properties and drug release according to changes in the wound environment, thereby improving the personalization and adaptability of treatment.

[0035] 5. Cross-linking treatment optimization

[0036] Uniform cross-linking: The use of calcium chloride cross-linking agent ensures the bonding between the layers and increases the mechanical strength and stability of the hydrogel. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is an electron microscopic image of a hydrogel in an embodiment of the present invention;

[0038] Figure 2 This is a diagram showing the in vitro antibacterial effect of the hydrogel in an embodiment of the present invention;

[0039] Figure 3 This is a comparison chart of the antibacterial effect of infected wounds on mice in the embodiments of the present invention;

[0040] Figure 4 This is a comparison diagram of the angiogenic effect on infectious wounds in mice according to the embodiments of the present invention;

[0041] Figure 5 It is a comparison chart of the healing speed of infectious wounds in mice in the embodiments of the present invention. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. 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.

[0043] Embodiment 1:

[0044] S1. Dissolve the base layer material:

[0045] S1.1 Photosensitive layer: In a container, add 27 ml of normal saline or PBS, then weigh 70 g of sodium alginate and 2 g of aminophthalocyanine, and stir with a stirrer to ensure that the sodium alginate is completely dissolved to form a uniform colloidal solution;

[0046] S1.2 Antibacterial layer: In another container, weigh 70 g of sodium alginate and 0.5 g of copper-based nanoparticles, add 27 ml of saline or PBS, and stir evenly using a stirrer to ensure that all ingredients are fully mixed to form a colloidal solution;

[0047] S1.3 Active molecule layer: In a separate container, weigh 70 g of sodium alginate and 0.01 g of miR-142-3p, add solvent, and stir evenly with a stirrer to ensure that miR-142-3p is completely dispersed in the solution;

[0048] S2. Forming a layered structure: pouring the colloidal solution of the photosensitizer layer into a pre-prepared mold, the thickness can be set as needed (e.g., 1-2 mm), and standing at room temperature until it is partially solidified to form a preliminary solidified layer; then adding the antibacterial layer, slowly pouring the colloidal solution of the antibacterial layer onto the base layer to ensure good contact between the two layers, and standing again until it is partially solidified; finally adding the bioactive molecule layer, gently pouring the mixture of the bioactive molecule layer onto the antibacterial layer to form a third layer, and standing to solidify;

[0049] S3. Cross-linking treatment: After the last layer in step S2 is cured, 0.5 mol / L calcium chloride solution is added to promote cross-linking of the entire structure so that each layer is firmly bonded; continue to stand for several minutes to ensure that all layers are evenly cross-linked;

[0050] S4. Post-processing: The entire layered hydrogel is removed from the mold, washed with PBS or saline to remove unreacted components, and then dried or freeze-dried;

[0051] S5. Storage: The synthesized layered hydrogel was placed in a sealed container and stored at low temperature to maintain the stability of its active ingredients.

[0052] According to the above method, an improved hydrogel dressing for treating diabetic wounds based on photodynamic therapy was prepared, and its electron microscopy image is as follows: Figure 1 shown.

[0053] 1. In vitro antibacterial test

[0054] 1.1 Material preparation

[0055] Culture medium: nutrient agar

[0056] Bacterial strains: Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli)

[0057] Experimental Group:

[0058] PBS group: normal saline (PBS)

[0059] Hydrogel group: experimentally synthesized hydrogels

[0060] 1.2 Cultivation of bacteria

[0061] Staphylococcus aureus (S. aureus) and Escherichia coli (E. co li) were inoculated onto nutrient agar medium respectively, ensuring that the bacteria were evenly distributed on the surface of the medium.

[0062] The agar plate was placed in a suitable temperature and environment for incubation (37°C for 24 hours) until the bacteria grew densely and formed colonies.

[0063] 1.3 Cutting experimental samples

[0064] Take out the grown nutrient agar plate and cut it into small pieces of uniform size using a sterile cutter or blade, suitable for placing the experimental group samples.

[0065] 1.4 Experimental Grouping

[0066] Divide the agar plates into two groups:

[0067] PBS group: Use a sterile pipette to draw an appropriate amount of physiological saline (PBS) and apply it on the agar plate to cover a small area;

[0068] Hydrogel group: Take an appropriate amount of the hydrogel prepared in Example 1 (for example, cut into suitable slices according to a set ratio or inject into a gel layer), and carefully place the hydrogel on an area of ​​another agar plate to ensure that it is in contact with the bacteria.

[0069] 1.5 Incubation

[0070] Place the treated agar plates back into the incubator at 37°C and continue culturing for 18-24 hours to promote bacterial growth on the agar plates and observe the antibacterial effect.

[0071] 1.6 Observe and record

[0072] The antibacterial effects of the two groups were observed, with special attention paid to the colonies in the hydrogel group and the PBS group.

[0073] 1.7 Data Analysis

[0074] The colonies of the PBS group and the hydrogel group were compared to analyze the antibacterial properties of the hydrogel. Figure 2 As shown, 2 colonies were observed in the hydrogel group, while the number of bacterial colonies in the control group was >30. The hydrogel showed good antibacterial effect in the in vitro antibacterial experiment.

[0075] 2. Mouse wound healing experiment:

[0076] 2.1 Experimental methods

[0077] Infectious wounds were created on 6 mice. The hydrogel dressings prepared in Example 1 were applied to the wounds of 3 mice, and the same amount of PBS was applied to the wounds of the other 3 mice as blank controls to observe the wound healing of the mice.

[0078] 2.2 Experimental results and analysis

[0079] The hydrogel showed good antibacterial effect on infected wounds in mice. Figure 3As shown, (a) After PBS and hydrogel were used to treat infected wounds of mice for 1 week, the bacterial colonies in the wound of the hydrogel group were significantly reduced. (b) Giemsa staining of the wound tissue showed that the bacteria in the wound of the hydrogel group were significantly less than those in the PBS group.

[0080] The hydrogel showed good angiogenic effect on infected wounds in mice, such as Figure 4 As shown, 5 days after hydrogel treatment, B-ultrasound of the blood vessels in the wound of mice showed that the number of blood vessels in the wound of the hydrogel group was significantly increased.

[0081] Comparison of wound healing speed Figure 5 As shown, after 14 days of treatment, the wound area in the hydrogel treatment group was significantly reduced.

[0082] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing an improved hydrogel dressing for treating diabetic wounds based on photodynamic therapy, characterized in that: The steps include: S1. Dissolve the base layer material: S1.1 Photosensitive layer: In a container, add solvent, weigh sodium alginate and aminophthalocyanine, and stir with a stirrer to ensure that the sodium alginate is completely dissolved. Form a homogeneous colloidal solution; S1.2 Antibacterial layer, in another container, weigh sodium alginate and copper-based nanoparticles, add solvent, and stir evenly with a stirrer to ensure that all ingredients are fully mixed to form a colloidal solution, wherein the mass ratio of sodium alginate to copper-based nanoparticles is 140:1, and the mass volume ratio of sodium alginate to solvent is 70:27 g / ml; S1.3 Active molecule layer: In a separate container, weigh sodium alginate and miR-142-3p, add solvent, and stir evenly using a stirrer to ensure that miR-142-3p is completely dispersed in the solution; S2. Forming a layered structure: pouring the colloidal solution of the photosensitizer layer into a pre-prepared mold, leaving it to stand at room temperature until it is partially solidified, so as to form a preliminarily solidified layer; then adding the antibacterial layer, slowly pouring the colloidal solution of the antibacterial layer onto the base layer to ensure good contact between the two layers, leaving it to stand again until it is partially solidified; finally adding the bioactive molecule layer, gently pouring the mixture of the bioactive molecule layer onto the antibacterial layer to form a third layer, and leaving it to stand to solidify; S3. Cross-linking treatment: After the last layer in step S2 is cured, calcium chloride solution is added to promote cross-linking of the entire structure so that each layer is firmly bonded; continue to stand for several minutes to ensure that all layers are evenly cross-linked; S4. Post-processing: The entire layered hydrogel is removed from the mold, washed with PBS or saline to remove unreacted components, and then dried or freeze-dried; S5. Storage: The synthesized layered hydrogel was placed in a sealed container and stored at low temperature to maintain the stability of its active ingredients.

2. The method for preparing an improved hydrogel dressing for treating diabetic wounds based on photodynamic therapy according to claim 1, characterized in that: In step S1.1, the mass ratio of sodium alginate to aminophthalocyanine is 35:1, and the mass volume ratio of sodium alginate to solvent is 70:27 g / ml.

3. The method for preparing an improved hydrogel dressing for treating diabetic wounds based on photodynamic therapy according to claim 1, characterized in that: In step S1.3, the mass ratio of sodium alginate to miR-142-3p was 7000:1, and the mass volume ratio of sodium alginate to solvent was 70:27 g / ml.

4. The method for preparing an improved hydrogel dressing for treating diabetic wounds based on photodynamic therapy according to claim 1, characterized in that: In step S1, the solvent is physiological saline or PBS.

5. A method for preparing an improved hydrogel dressing for treating diabetic wounds based on photodynamic therapy, characterized in that: In step S2, the thickness of the photosensitizer layer, the antibacterial layer and the active molecule layer are all 1-2 mm.

6. A method for preparing an improved hydrogel dressing for treating diabetic wounds based on photodynamic therapy, characterized in that: In step S3, the concentration of the calcium chloride solution is 0.5 mol / L.

7. An improved hydrogel dressing for treating diabetic wounds based on photodynamic therapy, characterized by: The invention is prepared by the method described in any one of claims 1 to 6.

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