Slow-release bletilla striata dressing combining carbon nanospheres to hydrogel

Abstract

The invention relates to the technical field of medical dressings, in particular to a slow-release bletilla striata dressing with carbon nanospheres combined to hydrogel, the dressing is hydrogel combined with the carbon nanospheres, bletilla striata polysaccharide is loaded on the surfaces of the carbon nanospheres, and tea tree oil is encapsulated in the carbon nanospheres; the technical problems of a traditional hydrogel dressing in the aspects of wound healing, antibiosis and drug sustained release are solved, the dressing has the effects of antibiosis and wound healing promotion, drug sustained release can be achieved, and the service time is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of medical dressings, and in particular to a sustained-release bletilla striata dressing in which carbon nanospheres are combined with a hydrogel. Background Art

[0002] Hydrogels are swollen, cross-linked semisolids formed by polymers or copolymers absorbing large amounts of water. They possess high water content, are soft and comfortable, and adhere well to wounds, providing a suitable healing environment. However, traditional hydrogel dressings face numerous challenges in wound care applications, including slow wound healing, limited antimicrobial efficacy, and difficulty in precisely regulating drug release, making them ineffective in providing sustained, effective wound treatment.

[0003] Bletilla striata (Bletilla striata) is the dried tuber of the orchid plant Bletilla striata. It has astringent and hemostatic properties, reduces swelling and promotes tissue regeneration, and clears heat and dampness. It is primarily used to treat surgical trauma, ulcers, pus, pulmonary tuberculosis, and hemoptysis. Bletilla striata polysaccharide, a key active ingredient in Bletilla striata, can promote platelet aggregation, forming a gel-like substance at the bleeding site, plugging damaged blood vessels and achieving hemostasis. It can also inhibit the growth of various bacteria and directly participate in the repair and metabolic processes of damaged tissues and cells, accelerating wound healing and reducing scar formation. In Yangzhou University's master's thesis, "Antibacterial Activity of FeS2-Modified Carbon Nanospheres and Their Synergistic Effect with Bletilla striata Polysaccharide in Treating Wound Infections," An Lanfang, a postdoctoral dissertation author, loaded carbon nanospheres with Bletilla striata polysaccharide and FeS2. The antibacterial effect is achieved through the use of divalent iron ions. Furthermore, the loaded Bletilla striata polysaccharide promotes cell proliferation and migration, resulting in carbon nanospheres loaded with Bletilla striata polysaccharide and FeS2 exhibiting superior antibacterial efficacy and rapid wound healing.

[0004] Therefore, carbon nanospheres loaded with bletilla striata polysaccharide and FeS2, which have better antibacterial effects and faster wound healing speed, are applied to traditional hydrogel dressings. It is possible to solve the disadvantages of traditional hydrogel dressings, such as slow wound healing speed, limited antibacterial efficacy, and difficulty in accurately regulating drug release. However, there are currently no reports combining the two, and how to combine carbon nanospheres with hydrogels and the effect of the dressing obtained after the combination is unknown. In addition, divalent iron ions are very easy to oxidize and can produce toxins to human cells, so they are not suitable for long-term use. Tea tree oil is a natural plant extract with good antibacterial and anti-inflammatory effects and can replace FeS2, but how to stably combine tea tree oil with carbon nanospheres is also a major problem. Summary of the Invention

[0005] The present invention provides a sustained-release Bletilla striata dressing in which carbon nanospheres are bonded to a hydrogel. The dressing is a hydrogel bonded with carbon nanospheres, the surface of the carbon nanospheres is loaded with Bletilla striata polysaccharide, and tea tree oil is encapsulated within the carbon nanospheres. The dressing has antibacterial and wound healing effects, can achieve sustained release of drugs, and prolongs the use time.

[0006] In order to solve the above technical problems, the technical solution of the present invention is:

[0007] A sustained-release bletilla striata dressing is provided by combining carbon nanospheres with a hydrogel. The dressing is a hydrogel combined with carbon nanospheres, the surface of the carbon nanospheres is loaded with bletilla striata polysaccharide, and tea tree oil is encapsulated in the carbon nanospheres.

[0008] The content of the carbon nanospheres in the dressing is 3% wt-12% wt; the content of the bletilla striata polysaccharide in the dressing is 1% wt-5% wt; and the content of the tea tree oil in the dressing is 0.5% wt-3% wt.

[0009] The particle size of the carbon nanospheres ranges from 50 to 300 nm.

[0010] Furthermore, tea tree oil and a carbon source are dissolved in water, wherein the concentration of the carbon source is 0.05-0.2 g / mL and the mass ratio of tea tree oil to carbon source is 1:(5-15). Ultrasonic stirring is performed to form a uniformly dispersed mixed solution, which is then placed in a sealed container for hydrothermal reaction at a certain temperature. After the reaction is completed, the mixture is cooled and centrifuged to remove unreacted substances, and then washed with water to remove excess tea tree oil and other residues, thereby obtaining carbon nanospheres encapsulating tea tree oil.

[0011] Specifically, the carbon source is glucose, sucrose, citric acid or maltose; specifically, the temperature of the hydrothermal reaction is 160-220° C., and the reaction time is 24-40 hours.

[0012] Furthermore, the carbon nanospheres and Bletilla striata polysaccharide are weighed and dissolved in ultrapure water, respectively. After ultrasonication until completely dispersed, the two dispersions are combined, and the combined dispersion has a mass ratio of carbon nanospheres to Bletilla striata polysaccharide of 1:(0.2-1). The combined dispersion is stirred for 12-20 hours and then centrifuged. The resulting precipitate is washed with ethanol and then dried to obtain carbon nanospheres with Bletilla striata polysaccharide surface-loaded. Preferably, the drying temperature is 45-50°C.

[0013] Furthermore, the hydrogel is prepared by adding a cross-linking agent to a natural high molecular polymer. Preferably, the natural high molecular polymer is sodium alginate and the cross-linking agent is calcium chloride.

[0014] Furthermore, the carbon nanospheres and the hydrogel are combined through click chemistry, and azide and alkyne groups are introduced on the carbon nanospheres and the hydrogel, respectively. In the presence of a copper (I) catalyst, the azide and alkyne groups undergo a cycloaddition reaction to connect the carbon nanospheres and the hydrogel.

[0015] Furthermore, the steps of combining the carbon nanospheres with the hydrogel are as follows: (1) preparing the alkyne hydrogel: dissolving sodium alginate in MES buffer at a concentration of 0.02 g / mL, adding EDC and NHS to activate for 30 minutes, adding propargylamine to react at room temperature for a period of time, wherein the amount of propargylamine added is 20% to 50% of the molar amount of carboxyl groups in the sodium alginate, dialysis and purification to obtain Alg-alkyne, mixing an Alg-alkyne solution with a mass fraction of 2% to 4% w / v with a CaCl2 solution with a mass fraction of 2% to 5% w / v, and allowing to stand for cross-linking to form an alkyne hydrogel;

[0016] (2) Preparation of azide-modified carbon nanospheres: dissolving carbon nanospheres and sodium azide in an organic solvent in an amount of 1 g:(5-10) g:(10-20) mL of carbon nanospheres, sodium azide, and organic solvent, and reacting under stirring at 60-80° C. for 12-24 hours to obtain azide-modified carbon nanospheres;

[0017] (3) The azide-modified carbon nanospheres and the alkyne-modified hydrogel are thoroughly mixed at a molar ratio of 1:1 between the azide and alkyne groups, and a copper (I) catalyst is added in an amount of 1% to 5% of the total molar number of the azide and alkyne groups. The mixture is stirred at room temperature for 2 to 4 hours to bind the carbon nanospheres to the hydrogel.

[0018] Furthermore, the dressing further comprises one or more of a thickener, a moisturizer, and a transdermal enhancer. Preferably, the thickener is sodium carboxymethylcellulose, the moisturizer is glycerol, and the transdermal enhancer is azone.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) The dressing provided by the present invention is a hydrogel combined with carbon nanospheres. The surface of the carbon nanospheres is loaded with bletilla striata polysaccharide, and tea tree oil is encapsulated in the carbon nanospheres. The dressing has antibacterial and wound healing effects, and can achieve sustained release of drugs and prolong the use time.

[0021] (2) The dressing provided by the present invention connects carbon nanospheres with hydrogels through a cycloaddition reaction. The elasticity and plasticity of the hydrogel are enhanced by the addition of carbon nanospheres, optimizing the internal structure of the hydrogel, giving the hydrogel better flexibility and toughness, improving the skin-friendliness of the dressing, and enabling the dressing to fit the wound contour closely. Even in active parts such as joints, good coverage and protection can be maintained, and it is not easy to be damaged and deformed, ensuring that the therapeutic effect is stable. At the same time, the surface properties and nanoscale size of the carbon nanospheres can affect the adhesion, spreading and proliferation behavior of cells. After introducing carbon nanospheres into the hydrogel, more attachment sites can be provided for cells, promoting the growth and reproduction of cells on the surface of the hydrogel, which is conducive to the repair and regeneration of tissues. In addition, utilizing the swelling-contraction characteristics of the hydrogel, it is possible to achieve the slow release of the tea tree oil encapsulated on the carbon nanospheres and the bletilla striata polysaccharide loaded when the dressing is used, achieving the effect of controlled release, continuously providing the therapeutic effects of tea tree oil and bletilla striata polysaccharide to the wound, and improving the therapeutic effect and bioavailability of the drug.

[0022] (3) In the present invention, tea tree oil is encapsulated in carbon nanospheres during the synthesis of carbon nanospheres, providing a relatively stable microenvironment for the tea tree oil, maintaining the chemical stability and biological activity of the tea tree oil, avoiding the volatilization and premature degradation of the tea tree oil, and enabling it to be stably present in the dressing system after being encapsulated. At the same time, the tea tree oil encapsulated in the carbon nanospheres can achieve more accurate and controllable release, prolonging its effective action time, avoiding irritation to the human body due to excessive local concentration, and improving the safety of use. Tea tree oil is continuously released at the wound, relying on its natural antibacterial properties, strongly inhibiting bacterial growth, reducing inflammatory reactions, and creating a favorable environment for wound healing. In addition, tea tree oil is relatively safe, stable, synergistic, and environmentally friendly, making it suitable for the design of medical dressings that require long-term antibacterial and healing promotion.

[0023] (4) The surface of the carbon nanospheres in the present invention is loaded with Bletilla striata polysaccharide. The antibacterial and anti-inflammatory properties of tea tree oil and the healing-promoting function of Bletilla striata polysaccharide cooperate with each other to produce a synergistic effect. While preventing and controlling wound infection, it actively promotes wound tissue regeneration and repair, comprehensively improving the speed and quality of wound healing, and has obvious advantages over traditional hydrogel dressings.

[0024] (5) The present invention combines carbon nanospheres containing hydrophobic tea tree oil with hydrophilic hydrogel to jointly regulate the hydrophilicity and hydrophobicity of the dressing. This balance enables the dressing to effectively absorb excess exudate from the wound and maintain appropriate moisture, while also promoting drug release and interaction with wound tissue, accelerating the healing process.

[0025] (6) The excellent biocompatibility of the Bletilla striata polysaccharide and the hydrogel in the present invention ensures that when the dressing contacts the wound, it will not trigger a severe immune response or toxic effects, providing a safe and gentle environment for wound repair and promoting tissue regeneration. Furthermore, the hydrogel itself has good biodegradability, which can reduce environmental pollution and conform to the current concept of environmental protection and sustainable development, making this material have greater advantages in the biomedical and environmental fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic structural diagram of the hydrogel combined with carbon nanospheres provided by the present invention;

[0027] Figure 2 A schematic diagram of the structure of carbon nanospheres provided by the present invention with bletilla striata polysaccharide loaded on the surface and tea tree oil encapsulated inside;

[0028] In the figure, 1-hydrogel, 2-carbon nanospheres, 3-bletilla striata polysaccharide, 4-tea tree oil. DETAILED DESCRIPTION

[0029] The present invention will be further described below with reference to the accompanying drawings and examples.

[0030] This embodiment provides a sustained-release Bletilla striata dressing in which carbon nanospheres are bonded to a hydrogel. The dressing is a hydrogel 1 bonded with carbon nanospheres 2. The surface of the carbon nanospheres is loaded with Bletilla striata polysaccharide 3, and tea tree oil 4 is encapsulated in the carbon nanospheres. Figure 1 and Figure 2 In this embodiment, the content of carbon nanospheres in the dressing is 6% wt, the content of bletilla striata polysaccharide in the dressing is 2.5% wt, and the content of tea tree oil in the dressing is 1.5% wt.

[0031] Furthermore, the particle size of the carbon nanospheres ranges from 50 to 300 nm.

[0032] Furthermore, the dressing also includes one or more of a thickener, a moisturizer, and a transdermal enhancer; the thickener is sodium carboxymethyl cellulose, the moisturizer is glycerol, and the transdermal enhancer is azone.

[0033] The method for preparing the sustained-release Bletilla striata dressing in this embodiment by combining carbon nanospheres with a hydrogel comprises the following steps:

[0034] (1) Preparation of carbon nanospheres encapsulating tea tree oil: tea tree oil and carbon source were dissolved in water, wherein the concentration of the carbon source was 0.1 g / mL and the mass ratio of tea tree oil to carbon source was 1:10. Ultrasonic treatment was performed for 30 min to ensure that the tea tree oil was evenly dispersed in the solution to form a stable mixed system. The evenly dispersed mixed solution was placed in a polytetrafluoroethylene-lined high-pressure reactor, and the reactor was placed in a precisely temperature-controlled oven. The temperature was raised to 180°C and maintained at this temperature for 24 hours to allow the carbon source to undergo carbonization reaction and the tea tree oil to be encapsulated in the formed carbon nanospheres. After the reaction was completed, the cooled reaction product was transferred to a centrifuge tube of a high-speed centrifuge, and the centrifugal speed was set to 5000 rpm and the centrifugal time was set to 20 minutes to precipitate the carbon nanospheres. The supernatant was carefully removed, the precipitated product was collected, and the precipitated product was washed with deionized water multiple times. After each wash, centrifugation was performed until no unreacted substances were detected in the washing liquid. The washed product was spread flat on a clean culture dish, placed in a vacuum drying oven, and dried at 60° C. for 12 hours to obtain dry carbon nanospheres encapsulating tea tree oil, which were stored in a dry, light-proof environment.

[0035] In this example, 100 mg of tea oil was initially added, and the supernatant after centrifugation was collected. Solvent extraction and subsequent gravimetric analysis revealed that approximately 19.5 mg of unencapsulated tea oil was separated, resulting in a calculated encapsulation efficiency of approximately 80.5%, a high tea oil encapsulation efficiency. By optimizing the preparation conditions (carbon source concentration, tea oil to carbon source mass ratio, and hydrothermal reaction temperature and time), the encapsulation efficiency of tea oil in carbon nanospheres can reach 70%-90%.

[0036] This example also simulated the stability of tea oil encapsulated in carbon nanospheres. The carbon nanospheres were stored at high temperature and humidity (40°C, 75% RH, 30 days). The simulation results showed that after 30 days, the encapsulation efficiency dropped by only about 5 percentage points to 75.5%, demonstrating good storage stability. After one year of storage at room temperature, the tea oil content in the tea oil-encapsulated carbon nanospheres remained above 85%, while the unencapsulated tea oil control group retained only 50%.

[0037] (2) Loading Bletilla striata polysaccharide on the surface of carbon nanospheres encapsulating tea tree oil: Accurately weigh the carbon nanospheres encapsulating tea tree oil and Bletilla striata polysaccharide, dissolve them in ultrapure water, and stir them using a magnetic stirrer to ensure complete dissolution and uniform solution state. The two dissolved solutions are placed in an ultrasonic cleaner and ultrasonically treated at an optimized ultrasonic frequency and time until the solid matter is completely and evenly dispersed and the solution is clear and transparent. The two dispersions are then slowly mixed together to form a mixed dispersion. The mass ratio of carbon nanospheres to Bletilla striata polysaccharide in the combined dispersion is 1:(0.2-1). The mixed dispersion is transferred to a magnetic stirrer and stirred continuously at room temperature for 12 hours to fully load Bletilla striata polysaccharide on the surface of the carbon nanospheres. The solution temperature is kept stable during the stirring process to avoid external factors interfering with the loading process. After the stirring is completed, the mixed solution is transferred to a centrifuge tube and centrifuged according to the predetermined centrifugal conditions. After centrifugation, the supernatant is carefully collected and properly retained for subsequent detection and analysis of indicators such as the loading rate. The precipitate was washed several times with an appropriate amount of ethanol to remove unloaded Bletilla striata polysaccharide and other impurities. The washed precipitate was dried in a 45°C oven to a constant weight to obtain carbon nanospheres loaded with Bletilla striata polysaccharide, ready for binding to the hydrogel.

[0038] (3) Preparation of alkyne hydrogel: Sodium alginate was dissolved in MES buffer at pH 6.0 at a concentration of 0.02 g / mL. EDC and NHS were added for activation for 30 minutes, wherein the amount of EDC added was 1.2 times the molar amount of carboxyl groups in sodium alginate, and the amount of NHS added was 0.5 times the molar amount of EDC. Propylamine was added and reacted at room temperature for 12 hours, wherein the amount of propylamine added was 20% to 50% of the molar amount of carboxyl groups in sodium alginate. Alg-alkyne was purified by dialysis, and the Alg-alkyne solution (2%-4% w / v) was mixed with CaCl2 solution (2%-5% w / v). The mixture was allowed to stand for cross-linking for 20 minutes to form an alkyne hydrogel.

[0039] (4) Preparation of azide-modified carbon nanospheres: The carbon nanospheres encapsulated with tea tree oil and loaded with bletilla striata polysaccharide on the surface prepared in step (2) are dissolved in an organic solvent (such as DMF) with sodium azide added in an amount of 1 g:(5-10) g:(10-20) mL. The mixture is stirred at 60-80° C. for 12-24 hours to obtain azide-modified carbon nanospheres.

[0040] (5) The azide-modified carbon nanospheres and the alkyne-modified hydrogel are fully mixed at a molar ratio of 1:1 between the azide and alkyne groups, and a copper (I) catalyst is added in an amount of 1%-5% of the total molar number of the azide and alkyne groups. The mixture is reacted for 2-4 hours under stirring at room temperature (20-25°C) to allow the azide and alkyne groups to undergo an efficient cycloaddition reaction, thereby achieving a stable combination of the carbon nanospheres and the hydrogel, and obtaining the final sustained-release Bletilla striata dressing in which the carbon nanospheres are combined with the hydrogel.

[0041] The antibacterial efficiency of the dressing prepared in this embodiment can reach 90%-95%, with good antibacterial effect. Moreover, the dressing can significantly accelerate wound healing. Compared with traditional hydrogel dressings, the healing time can be shortened to 5-6 days, and complete healing can be achieved in about 12 days, with a healing rate increased by about 36%. When the dressing is applied to the affected area of ​​mice, the hydrogel absorbs the exudate and slowly releases the bletilla polysaccharide and tea tree oil. It can continuously release the active ingredients within 8-10 hours, maintaining a relatively stable drug concentration, thereby continuously exerting antibacterial, anti-inflammatory and healing effects.

Claims

1. A sustained-release Bletilla striata dressing in which carbon nanospheres are bonded to a hydrogel, characterized by: The dressing is a hydrogel combined with carbon nanospheres, the surface of the carbon nanospheres is loaded with bletilla striata polysaccharide, and tea tree oil is encapsulated in the carbon nanospheres.

2. The sustained-release Bletilla striata dressing comprising carbon nanospheres bonded to a hydrogel according to claim 1, characterized in that: The content of the carbon nanospheres in the dressing is 3% wt-12% wt; the content of the bletilla striata polysaccharide in the dressing is 1% wt-5% wt; and the content of the tea tree oil in the dressing is 0.5% wt-3% wt.

3. The sustained-release Bletilla striata dressing comprising carbon nanospheres bonded to a hydrogel according to claim 1, characterized in that: The particle size of the carbon nanospheres ranges from 50 to 300 nm.

4. The sustained-release Bletilla striata dressing comprising carbon nanospheres bonded to a hydrogel according to claim 1, characterized in that: Tea tree oil and a carbon source are dissolved in water, wherein the concentration of the carbon source is 0.05-0.2 g / mL and the mass ratio of tea tree oil to carbon source is 1:(5-15). Ultrasonic stirring is performed to form a uniformly dispersed mixed solution, which is then placed in a sealed container for hydrothermal reaction under certain temperature conditions. After the reaction is completed, the mixture is cooled, centrifuged, and washed with water to obtain carbon nanospheres encapsulating tea tree oil.

5. The sustained-release Bletilla striata dressing comprising carbon nanospheres bonded to a hydrogel according to claim 4, characterized in that: The carbon source is glucose, sucrose, citric acid or maltose; the temperature of the hydrothermal reaction is 160-220° C., and the reaction time is 24-40 hours.

6. The sustained-release Bletilla striata dressing comprising carbon nanospheres bonded to a hydrogel according to claim 1, characterized in that: Weigh carbon nanospheres and Bletilla striata polysaccharide, dissolve them in ultrapure water respectively, and combine the two dispersions after complete dispersion by ultrasonication. The mass ratio of carbon nanospheres to Bletilla striata polysaccharide in the combined dispersion is 1:(0.2-1). Stir for 12-20 hours and then centrifuge. The resulting precipitate is washed with ethanol and then dried to obtain carbon nanospheres with Bletilla striata polysaccharide loaded on the surface.

7. The sustained-release Bletilla striata dressing comprising carbon nanospheres bonded to a hydrogel according to claim 1, characterized in that: The hydrogel is prepared by adding a cross-linking agent to a natural high molecular polymer.

8. The sustained-release Bletilla striata dressing comprising carbon nanospheres bonded to a hydrogel according to claim 1, characterized in that: The carbon nanospheres and hydrogels are combined through click chemistry. Azide and alkyne groups are introduced on the carbon nanospheres and hydrogels respectively. In the presence of copper (I) catalyst, the azide and alkyne groups undergo a cycloaddition reaction to connect the carbon nanospheres and hydrogel.

9. The sustained-release Bletilla striata dressing comprising carbon nanospheres bonded to a hydrogel according to claim 8, characterized in that: The steps of combining the carbon nanospheres with the hydrogel are as follows: (1) Preparation of alkyne hydrogel: Sodium alginate was dissolved in MES buffer at a concentration of 0.02 g / mL, EDC and NHS were added for activation for 30 minutes, propargylamine was added and reacted at room temperature for a period of time, the amount of propargylamine added was 20% to 50% of the molar amount of carboxyl groups in sodium alginate, Alg-alkyne was obtained by dialysis purification, 2% to 4% w / v Alg-alkyne solution was mixed with 2% to 5% w / v CaCl solution, and the mixture was allowed to stand for cross-linking to form alkyne hydrogel; (2) Preparation of azide-modified carbon nanospheres: dissolving carbon nanospheres and sodium azide in an organic solvent in an amount of 1 g:(5-10) g:(10-20) mL of carbon nanospheres, sodium azide, and organic solvent, and reacting under stirring at 60-80° C. for 12-24 hours to obtain azide-modified carbon nanospheres; (3) The azide-modified carbon nanospheres and the alkyne-modified hydrogel are thoroughly mixed at a molar ratio of 1:1 between the azide and alkyne groups, and a copper (I) catalyst is added in an amount of 1% to 5% of the total molar number of the azide and alkyne groups. The mixture is stirred at room temperature for 2 to 4 hours to bind the carbon nanospheres to the hydrogel.

10. The sustained-release Bletilla striata dressing comprising carbon nanospheres bonded to a hydrogel according to claim 1, characterized in that: The dressing further comprises one or more of a thickener, a moisturizer, and a transdermal enhancer.

Images