MOF-based wound dressing and preparation method thereof

Abstract

The invention belongs to the field of hydrogel application, and discloses an MOF-based wound dressing and a preparation method thereof, and the MOF-based wound dressing is a composite material prepared by reaction of carrier hydrogel GHA (GelMA / HAMA) and Cu / ZIF-8-coated Cur antibacterial particles. The GHA hydrogel is formed by the cross-linking of methacrylated gelatin (GelMA) and methacrylated hyaluronic acid (HAMA). The invention further discloses a preparation method of the GHA hydrogel. The problems of wound infection, slow healing speed and the like caused by lack of controllable hygroscopicity, poor antibacterial property and the like of the existing wound dressing can be solved, and the wound dressing has biocompatibility, pH responsiveness and antibacterial property.

Description

Technical Field

[0001] The present invention belongs to the field of hydrogel applications, and particularly relates to a gelatin material loaded with a dual-metal MOF structure with hemostatic and antibacterial functions and drugs. Background Art

[0002] As an important defense line of the human body, the skin not only effectively resists the invasion of pathogens, but also plays a key role in preventing physical damage and protecting internal organs. When the human body is injured, the moist wound environment is extremely prone to infection, breeding bacteria and causing continuous inflammatory reactions. Developing more effective wound dressings is an urgent need at present.

[0003] The anti-infection ability of traditional dressings is weak, and the promotion of healing effect is also not satisfactory. With the wet wound healing theory being increasingly well-known and widely accepted by the public, wet dressings have been recognized in the field of wound care and become a research hotspot. Among them, hydrogels stand out among many wet dressings due to their unique three-dimensional porous structure, high water content, good biocompatibility, and similarity to the extracellular matrix, and become a popular material for treating wound bleeding. At present, there have been a large number of studies on injectable, self-healing or highly adhesive hydrogel wound dressings, but the functions of these hydrogels are often relatively single and difficult to deal with the problems of wound bleeding and bacterial growth at the same time, and their performance needs to be further improved.

[0004] Curcumin (Cur) is a natural compound widely present in ginger plants, which has the effects of inhibiting cell growth and anti-tumor. It can not only promote wound healing, inhibit the production of inflammatory factors, but also has good protective effects on multiple organ systems such as the gastrointestinal tract, respiratory system, cardiovascular system, liver, and nervous system.

[0005] With the development of science and technology, it has been found that encapsulating the target drug into a carrier to achieve its slow release is an effective method to promote wound healing. MOFs have been widely used in various fields due to their advantages such as dense pores, excellent drug loading performance, simple preparation method, and pH responsiveness. Among them, Gallis et al. used ZIF-8 as a sustained-release carrier of the antibacterial agent ceftazidime, which can achieve drug release for up to one week and effectively kill bacteria.

[0006] However, single-metal MOFs have certain limitations in terms of stability, biocompatibility, and drug release performance, and their functional diversity needs to be further improved. Summary of the Invention

[0007] In view of the problems of wound infection and slow wound healing caused by existing wound dressings due to lack of controllable hygroscopicity and poor antibacterial performance, etc., the present invention provides a MOF-based wound dressing with dual functions of hemostasis and antibacterial, aiming to promote wound healing by loading curcumin on bimetallic MOF and using modified gelatin as a carrier. This material has the advantages of good biocompatibility, coagulation performance, high drug loading rate, and high antibacterial rate, etc.

[0008] The technical solution of the present invention:

[0009] A MOF-based wound dressing, characterized in that the wound dressing uses a hydrogel formed by cross-linking methacrylated gelatin GelMA and methacrylated hyaluronic acid HAMA as a carrier, and loads curcumin Cur and bimetallic organic framework Cu / ZIF-8 as antibacterial particles.

[0010] Furthermore, the MOF-based wound dressing has the functions of hemostasis and antibacterial.

[0011] A preparation method of a MOF-based wound dressing, the steps are as follows:

[0012] Step 1, prepare GelMA solution and HAMA solution

[0013] Dissolve GelMA in water to form a GelMA solution; dissolve HAMA in water to form a HAMA solution;

[0014] Step 2, prepare Cu / ZIF-8@Cur

[0015] Mix zinc nitrate hexahydrate and copper nitrate trihydrate, and dissolve them with anhydrous methanol; fully dissolve 2-methylimidazole with anhydrous methanol, and then add curcumin; mix the two solutions, stir, centrifuge, wash, and put them in an oven to dry to obtain Cu / ZIF-8@Cur;

[0016] Step 3, prepare Cu / ZIF-8@Cur-GHA

[0017] Weigh the Cu / ZIF-8@Cur prepared in Step 2 and add it to the HAMA solution, then pour the HAMA mixed solution into the GelMA solution, add the photoinitiator LAP, and polymerize under the light source to obtain a GelMA / HAMA hydrogel loaded with Cu / ZIF-8@Cur, that is, Cu / ZIF-8@Cur-GHA.

[0018] Furthermore, in the above-mentioned Step 1, the mass concentration of the GelMA solution is 10%; the mass concentration of the HAMA solution is 2% - 10%.

[0019] Further, in the second step, the mass ratio of zinc nitrate hexahydrate to copper nitrate trihydrate added is 1:0.08 - 0.33; the mass ratio of 2-methylimidazole to curcumin added is 1 - 1.14:0.016 - 0.07; the mass ratio of zinc nitrate hexahydrate to 2-methylimidazole is 1:2.1 - 2.4. The drying temperature is 55 - 65 °C, and the drying time is 10 h - 12 h.

[0020] Further, in the third step, the mass ratio of Cu / ZIF-8@Cur to HAMA and GelMA is 0.25 - 1:0.2 - 1:1. The mass ratio of the photoinitiator LAP to Cu / ZIF-8@Cur is 1 - 3:12.5 - 50. The intensity of the light source is 250 - 300 mW / cm 2 , and the wavelength is 365 - 405 nm.

[0021] Further, it is characterized in that the mass fraction of Cu in Cu / ZIF-8@Cur is 10% - 40%.

[0022] Further, the Cu / ZIF-8@Cur composite particles have pH responsiveness, that is, they show good stability when no bacteria are present (neutral condition); when bacteria are present (the environment becomes weakly acidic), the Cu / ZIF-8@Cur particles will slowly release Cu 2+ , Zn 2+ and curcumin.

[0023] Further, the methacrylated gelatin (GelMA) has the effects of promoting platelet aggregation and activation, promoting cell adhesion and migration, etc., and is a hydrogel with excellent biocompatibility, low cost and easy availability.

[0024] Further, the bactericidal substance is mainly curcumin (Cur). It can effectively scavenge a variety of reactive oxygen species, including hydroxyl radicals, nitrogen dioxide radicals and superoxide anions, etc., and shows a significant inhibitory effect on the lipid peroxidation process, and also shows multiple pharmacological activities such as anti-inflammatory, anti-cancer and anti-allergic, and can play a synergistic role in improving sensitivity and reducing drug resistance when combined with other drugs.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) The present invention proposes a scheme of combining a hydrogel and a MOF for use as a wound dressing, which combines the good biocompatibility of the hydrogel and the excellent antibacterial property of the MOF particles, can promote wound healing, and is an ideal design for developing the next generation of multifunctional wound dressings.

[0027] (2) The present invention uses the method of loading drugs with bimetallic MOF to inhibit bacterial growth. The prepared material has excellent pH responsiveness, that is, it maintains a stable structure under neutral conditions and gradually releases curcumin and Cu 2+ , Zn 2+ , achieving a strong antibacterial effect. Description of the Drawings

[0028] Figure 1 is a scanning electron microscope photograph of the microscopic morphology of a MOF-based wound dressing of the present invention;

[0029] Figure 2 is the pH response curve of a MOF-based antibacterial particle;

[0030] Figure 3 is the antibacterial effect diagram of a MOF-based wound dressing. Detailed Embodiments

[0031] Next, the technical solutions in the embodiments of the present invention will be described completely and clearly in conjunction with the drawings in the embodiments of the present invention. The described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. It should be noted that based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts belong to the scope of protection of the present invention.

[0032] This embodiment includes a Cu / ZIF-8@Cur-GHA composite hydrogel wound dressing formed by the reaction of a carrier hydrogel GelMA / HAMA (GHA) and antibacterial particles Cu / ZIF-8@Cur.

[0033] Example 1:

[0034] Step 1: Prepare GelMA solution and HAMA solution

[0035] Weigh 0.1 g of GelMA and dissolve it in 1 mL of water to form a GelMA solution; weigh 0.02 g of HAMA and dissolve it in 1 mL of water to form a HAMA solution;

[0036] Step 2: Prepare Cu / ZIF-8@Cur

[0037] Mix 0.73 g of zinc nitrate hexahydrate and 0.148 g of copper nitrate trihydrate, and dissolve them with 50 mL of anhydrous methanol; weigh 1.63 g of 2-methylimidazole, fully dissolve it with 50 mL of anhydrous methanol and then add 75 mg of curcumin; mix the two solutions, stir, centrifuge, wash, and place them in an oven at 60 °C for drying for 10 h to obtain Cu / ZIF-8@Cur, where the mass fraction of Cu is 25%;

[0038] Step 3: Preparation of Cu / ZIF-8@Cur-GHA

[0039] Weigh 75 mg of Cu / ZIF-8@Cur prepared in Step 2 and add it to the HAMA solution. Then pour the HAMA mixed solution into the GelMA solution, add 2 mg of photoinitiator LAP, and polymerize it under the conditions of an intensity of 300 mW / cm 2 and a wavelength of 365 nm to obtain a GelMA / HAMA hydrogel loaded with Cu / ZIF-8@Cur, namely Cu / ZIF-8@Cur-GHA.

[0040] Example 2:

[0041] Step 1: Preparation of GelMA solution and HAMA solution

[0042] Weigh 0.1 g of GelMA and dissolve it in 1 mL of water to form a GelMA solution; weigh 0.06 g of HAMA and dissolve it in 1 mL of water to form a HAMA solution;

[0043] Step 2: Preparation of Cu / ZIF-8@Cur

[0044] Mix 0.73 g of zinc nitrate hexahydrate and 0.059 g of copper nitrate trihydrate, and dissolve them with 50 mL of anhydrous methanol; weigh 1.6 g of 2-methylimidazole, fully dissolve it with 50 mL of anhydrous methanol, and then add 45 mg of curcumin; mix the two solutions, stir, centrifuge, wash, and dry them in an oven at 55 °C for 10 h to obtain Cu / ZIF-8@Cur, where the mass fraction of Cu is 10%;

[0045] Step 3: Preparation of Cu / ZIF-8@Cur-GHA

[0046] Weigh 45 mg of Cu / ZIF-8@Cur prepared in Step 2 and add it to the HAMA solution. Then pour the HAMA mixed solution into the GelMA solution, add 3 mg of photoinitiator LAP, and polymerize it under the conditions of an intensity of 250 mW / cm 2 and a wavelength of 405 nm to obtain a GelMA / HAMA hydrogel loaded with Cu / ZIF-8@Cur, namely Cu / ZIF-8@Cur-GHA.

[0047] Example 3:

[0048] Step 1: Preparation of GelMA solution and HAMA solution

[0049] Weigh 0.1 g of GelMA and dissolve it in 1 mL of water to form a GelMA solution; weigh 0.1 g of HAMA and dissolve it in 1 mL of water to form a HAMA solution;

[0050] Step 2: Preparation of Cu / ZIF-8@Cur

[0051] Mix 0.73 g of zinc nitrate hexahydrate and 0.24 g of copper nitrate trihydrate, and dissolve them in 50 mL of anhydrous methanol; weigh 1.73 g of 2-methylimidazole, fully dissolve it in 50 mL of anhydrous methanol, and then add 100 mg of curcumin; mix the two solutions, stir, centrifuge, wash, and place them in an oven at 65 °C for drying for 11 h to obtain Cu / ZIF-8@Cur, where the mass fraction of Cu is 40%;

[0052] Step 3. Preparation of Cu / ZIF-8@Cur-GHA

[0053] Weigh 25 mg of Cu / ZIF-8@Cur prepared in Step 2 and add it to the HAMA solution, then pour the HAMA mixed solution into the GelMA solution, add 6 mg of photoinitiator LAP, and polymerize it under the conditions of an intensity of 270 mW / cm 2 , a wavelength of 375 nm to obtain a GelMA / HAMA hydrogel loaded with Cu / ZIF-8@Cur, namely Cu / ZIF-8@Cur-GHA.

[0054] In Example 1, preferably, Figure 1 It is a SEM image of the microscopic morphology of a MOF-based wound dressing. The prepared hydrogel presents a porous network structure with pore sizes ranging from 1 μm to 5 μm, and a structure of large pores enclosing small pores appears in some places. This structure is more conducive to the absorption of moisture and blood, thus playing a role in hemostasis. At the same time, particles consistent with the crystal structure of Cu / ZIF-8@Cur are found in the pores, further indicating the successful introduction of Cu / ZIF-8@Cur particles into the GHA hydrogel.

[0055] In Example 1, preferably, Figure 2It is a pH response curve of MOF-based antibacterial particles. Weigh 10 mg of Cu / ZIF-8@Cur. After measuring its encapsulation efficiency, disperse 10 mg of the material in 10 mL of PBS solution containing 0.5 v / v% Tween 20. Take out 1 mL for measurement at specific time points and supplement 1 mL of fresh PBS solution containing 0.5 v / v% Tween 20. Dilute the taken-out solution with methanol and measure the absorbance at 425 nm, and calculate the release amount of curcumin according to the standard curve. It can be seen from the figure that as the acidity increases, the release rate of curcumin gradually accelerates and the release amount gradually increases. When pH = 7.4, the release amount of curcumin within 20 h is about 15%. When pH = 6.5 and 5.5, the release amounts of curcumin within 20 h are 25% and 30% respectively. This result shows that Cu / ZIF-8@Cur has excellent pH responsiveness. It has a certain stability in neutrality. When bacteria are produced in the human body, the pH will decrease, and the Cu / ZIF-8@Cur particles will slowly release curcumin at acidic pH values, thereby exerting its own powerful medicinal effect.

[0056] In Example 1, preferably, Figure 3 It is an antibacterial effect diagram of a MOF-based wound dressing. Use two kinds of bacteria, Escherichia coli and Staphylococcus aureus, for antibacterial performance testing. Transfer an Escherichia coli / Staphylococcus aureus colony on the selective medium to 3 mL of LB liquid medium and culture overnight at 37 °C and 200 rpm. Dilute the two overnight bacterial suspensions and take 1 mL each and drop them into equal amounts of PBS buffer, GHA, Cu / ZIF-8@Cur, and Cu / ZIF-8@Cur-GHA, place them on a shaker, and culture at 37 °C and 200 rpm for 6 h. Then pipette 50 μL and spread it on the LB solid medium, place it upside down in an incubator, and culture overnight at 37 °C to observe the number of colonies. Weigh 0.1 g of GelMA and dissolve it in 1 mL of water to form a GelMA solution; weigh 0.02 g of HAMA and dissolve it in 1 mL of water to form a HAMA solution. Pour the HAMA solution into the GelMA solution, mix well, add 2 mg of photoinitiator LAP, and polymerize for 3 minutes under a 365 nm light source with an intensity of 300 mW / cm 2 to obtain a GelMA / HAMA hydrogel, that is, a GHA hydrogel. As shown in the figure, a large number of colonies appeared on the surface of the agar plate coated with the bacterial solution treated with the GHA hydrogel. However, there were basically no colonies formed on the surface of the agar plate coated with the bacterial solution treated with Cu / ZIF-8@Cur, and the antibacterial rate was close to 100%, showing extremely excellent antibacterial properties.

[0057] The specific embodiments of the present invention have been described in detail above. It can be understood that the above embodiments are merely exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A MOF-based wound dressing, characterized in that, The wound dressing uses a hydrogel formed by crosslinking methacrylated gelatin GelMA and methacrylated hyaluronic acid HAMA as a carrier, and loads curcumin Cur and bimetallic organic framework Cu / ZIF-8 as antibacterial particles.

2. The MOF-based wound dressing according to claim 1, wherein The MOF-based wound dressing has hemostatic and antibacterial functions.

3. The preparation method of a MOF-based wound dressing according to any one of claims 1-2, characterized in that, The steps are as follows: Step 1. Prepare GelMA solution and HAMA solution Dissolve GelMA in water to form a GelMA solution; dissolve HAMA in water to form an HAMA solution. Step 2. Prepare Cu / ZIF-8@Cur Mix zinc nitrate hexahydrate and copper nitrate trihydrate and dissolve them in anhydrous methanol; fully dissolve 2-methylimidazole in anhydrous methanol and then add curcumin; mix the two solutions, stir, centrifuge, wash, and place in an oven to dry to obtain Cu / ZIF-8@Cur. Step 3. Prepare Cu / ZIF-8@Cur-GHA Weigh the Cu / ZIF-8@Cur prepared in Step 2 and add it to the HAMA solution, then pour the HAMA mixed solution into the GelMA solution, add the photoinitiator LAP, and polymerize under a light source to obtain a GelMA / HAMA hydrogel loaded with Cu / ZIF-8@Cur, that is, Cu / ZIF-8@Cur-GHA.

4. The preparation method of a MOF-based wound dressing according to claim 3, characterized in that, In Step 1, the mass concentration of the GelMA solution is 10%; the mass concentration of the HAMA solution is 2% - 10%.

5. The preparation method of a MOF-based wound dressing according to claim 3, wherein, In Step 2, the mass ratio of the added zinc nitrate hexahydrate to copper nitrate trihydrate is 1:0.08 - 0.33; the mass ratio of the added 2-methylimidazole to curcumin is 1 - 1.14:0.016 - 0.07; the mass ratio of zinc nitrate hexahydrate to 2-methylimidazole is 1:2.1 - 2.4; the drying temperature is 55 - 65 °C, and the drying time is 10h - 12h.

6. The preparation method of a MOF-based wound dressing according to claim 3, characterized in that, In the third step described above, the mass ratio of Cu / ZIF-8@Cur to HAMA and GelMA is 0.25 - 1:0.2 - 1:1; the mass ratio of photoinitiator LAP to Cu / ZIF-8@Cur is 1 - 3:12.5 - 50; the intensity of the light source is 250 - 300 mW / cm 2 , and the wavelength is 365 - 405 nm.

7. The preparation method of a MOF-based wound dressing according to claim 3, characterized in that The mass fraction of Cu in Cu / ZIF-8@Cur is 10% - 40%.

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