Preparation method of nano composite material and application of nano composite material in promoting healing of bacterial infectious wounds

Abstract

The invention provides a preparation method of a nano composite material and application of the nano composite material in promoting healing of bacterial infectious wounds. The nano composite material is specifically formed by compounding green synthesized silver nanoparticles and curcumin entrapped by a metal organic framework material ZIF-8, and has good antibacterial property, photodynamic property and biocompatibility. Animal experiment results show that compared with single use of nano-silver and curcumin, the nano composite material has a remarkable healing promoting effect on bacterial infectious wounds, and the nano composite material has wide clinical application potential on treatment of the bacterial infectious wounds.

Description

Technical Field

[0001] The present invention belongs to the field of nanomaterials and biomedicine technology, and relates to the preparation of nanocomposites and their application in promoting the healing of bacterial-infected wounds. Specifically, it relates to a nanocomposite material comprising green synthetic silver nanoparticles and curcumin-encapsulated by a metal-organic framework material ZIF-8, and its application in promoting the healing of bacterial-infected wounds. Background Art

[0002] In recent years, bacterial infections of wound tissue have become increasingly serious, and the accompanying rise in antibiotic resistance has exacerbated treatment challenges. The use of a single antimicrobial agent is no longer sufficient to meet clinical needs. Clinical treatments for wound healing include surgical debridement, tissue transplantation, wound dressings, and hyperbaric oxygen therapy. However, these approaches are plagued by long healing times, high costs, immune rejection, and susceptibility to infection, limiting their widespread application.

[0003] The development of nanotechnology has provided a new approach for this. Due to its unique physical and chemical properties, nanomaterials have shown significant antibacterial activity, especially silver nanoparticles (AgNPs). S ) has attracted much attention due to its broad-spectrum antibacterial properties. S The antibacterial mechanism mainly includes direct destruction of cell walls and cell membranes, release of Ag + Damage bacteria, generate reactive oxygen species by catalyzing water or oxygen, and regulate bacterial metabolism, protein and DNA replication, etc. However, AgNP S After absorption, it may accumulate in tissues and organs such as the skin, liver, lungs, kidneys and blood, causing many adverse reactions. S Biocompatibility, safety and environmental protection during synthesis and use, as well as reducing its cost of use, are still issues that need to be addressed.

[0004] Curcumin (Cur) is one of the main active ingredients extracted from the dried rhizome of Curcuma longa (Turmeric), a plant of the Curcumaceae family. As a natural photosensitizer, curcumin possesses many of the characteristics of an ideal photosensitizer, including a well-defined structure, a single component, a strong ability to generate reactive oxygen species, minimal toxicity, and low cost. Therefore, it has been widely used in antibacterial photodynamic therapy. However, Cur also has drawbacks such as poor water solubility, poor stability, and a short duration of photosensitivity, which limit its application.

[0005] Therefore, a method combining AgNP with broad-spectrum antimicrobial agents was developed. S As well as the new composite antibacterial strategy of Cur photodynamic therapy, it is important to improve the AgNP S The biocompatibility and water solubility of Cur are of great significance as they can effectively inhibit the growth of pathogens and promote the healing of bacterial-infected wounds. Summary of the Invention

[0006] The present invention aims to provide a method for preparing a nanocomposite material that can overcome the shortcomings of easy aggregation of silver nanoparticles and poor water solubility of curcumin, thereby achieving a synergistic antibacterial effect and playing an important role in the healing of bacterial-infected wounds, and its application in promoting the healing of bacterial-infected wounds.

[0007] To achieve the above object, the preparation method adopted by the present invention is as follows:

[0008] 1) taking an aqueous extract of the herbaceous plant and adjusting its pH to 5-9, then adding a 4-8 mmol / L silver nitrate solution to the aqueous extract of the herbaceous plant at a volume ratio of 1:1-9, and allowing the solution to react to obtain a dark brown colloidal solution of silver nanoparticles;

[0009] 2) zinc nitrate hexahydrate, 2-methylimidazole, and curcumin are taken separately at a molar ratio of zinc nitrate hexahydrate to 2-methylimidazole of 1:4-12 and a mass ratio of curcumin (Cur) to 2-methylimidazole solution of 1:50-80. The zinc nitrate hexahydrate, 2-methylimidazole, and curcumin are then ultrasonically dissolved in ultrapure water to obtain a zinc nitrate solution having a zinc ion concentration of 0.05-0.15 mol / L. Curcumin (Cur) and 2-methylimidazole solution are ultrasonically dissolved in anhydrous methanol to obtain a curcumin-containing 2-methylimidazole solution having a Cur concentration of 300-700 μg / mL. The zinc nitrate solution is rapidly added to the curcumin-containing 2-methylimidazole solution under magnetic stirring, stirred evenly, and allowed to stand to obtain a ZIF-8@Cur solution.

[0010] 3) According to ZIF-8@Cur and AgNP S Add AgNPs to the ZIF-8@Cur solution at a volume ratio of 1 to 30:1. S , ZIF-8@Cur&AgNP was prepared after ultrasonic mixing S Nanocomposite solution; the nanocomposite solution after the reaction was centrifuged at high speed, the precipitate was collected and redispersed in methanol, and the supernatant was discarded after repeated washing. The obtained product was fully dried in a vacuum drying oven to obtain orange ZIF-8@Cur&AgNP S Nanocomposite materials.

[0011] The pH value of the water extract of the herb is adjusted by using hydrochloric acid or sodium hydroxide solution.

[0012] The static reaction time in step 1) is 3 to 15 hours.

[0013] The standing time in step 2) is 12 to 36 hours.

[0014] In the step 3), the centrifugal speed is 8000-15000 rpm, and the centrifugal time is 10-30 min.

[0015] In the step 3), the vacuum drying temperature is 40-60° C., and the drying time is 12-36 hours.

[0016] ZIF-8@Cur&AgNP prepared by the above method S Nanocomposites Application of nanocomposites in promoting healing of bacterially infected wounds.

[0017] The present invention uses the bioactive components in the water extract of goose grass as reducing agents and stabilizers to greenly synthesize silver nanoparticles (AgNPs) S ); zinc nitrate hexahydrate and 2-methylimidazole are used as precursors to form a ZIF-8 organic framework through the coordination of zinc ions with nitrogen atoms in 2-methylimidazole; curcumin is added in a one-pot method during the reaction to obtain a curcumin-loaded metal-organic framework material ZIF-8@Cur; ZIF-8@Cur is fully mixed with silver nanoparticles greenly synthesized from an aqueous extract of scutellaria baicalensis, and the mixture is centrifuged, washed, and dried to obtain a nanocomposite material ZIF-8@Cur&AgNP. S Specifically, green synthesized silver nanoparticles are combined with curcumin encapsulated in the metal-organic framework material ZIF-8 to prepare a nanocomposite material with uniform morphology and uniform dispersion, which has good antibacterial properties, photodynamic properties and biocompatibility.

[0018] The present invention uses the water extract of the medicinal plant Capilla ovata as a reducing agent and a stabilizer to prepare AgNPs using a green synthesis method. S It has the advantages of wide raw material sources, low cost, mild and controllable reaction conditions, high efficiency and energy saving. It is safe, environmentally friendly and easy to operate, and has good biocompatibility, which meets the needs of sustainable development. Zeolite imidazolate framework-8 (ZIF-8) is composed of zinc ions and 2-methylimidazole connected by coordination bonds. It has high specific surface area, rich pore structure and pH response. The use of ZIF-8 as a nanocarrier for loading Cur can improve the water solubility and stability of curcumin and achieve a sustained release effect.

[0019] Green synthesized AgNPs S Combined with ZIF-8-encapsulated Cur, AgNP S A novel nanocomposite material ZIF-8@Cur&AgNP was synthesized based on the antibacterial properties of Cur and its photodynamic antibacterial therapy SIn vitro experimental results confirmed that the nanocomposite material had a hemolysis rate of less than 5%, relatively high cell viability, and good biocompatibility. The results of promoting the healing of bacterial-infected wounds in full-thickness skin defects in mice showed that compared with the use of a single material alone, the application of the nanocomposite material to the wound surface significantly shortened the healing time and increased the wound healing rate, providing new ideas and potential application pathways for the clinical treatment of bacterial infections. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The particle size distribution of the four nanomaterials prepared in Example 1 (a: AgNP S ;b:ZIF-8; c:ZIF-8@Cur; d:ZIF-8@Cur&AgNP S );

[0021] Figure 2 Transmission electron microscopy images of four nanomaterials prepared in Example 1 (a: AgNP S ;b:ZIF-8; c:ZIF-8@Cur; d:ZIF-8@Cur&AgNP S ).

[0022] Figure 3 For the four nanomaterials (AgNP S , ZIF-8, ZIF-8@Cur, ZIF-8@Cur&AgNP S ) of the hemolysis rate. *** indicates p < 0.001 between the experimental group and the control group.

[0023] Figure 4 For the four nanomaterials (AgNP S , ZIF-8, ZIF-8@Cur, ZIF-8@Cur&AgNP S ) and L929 cells for 24 h.

[0024] Figure 5 AgNP S , ZIF-8@Cur, ZIF-8@Cur&AgNP S (L + ), ZIF-8@Cur&AgNP S (L - ) Skin wound healing rates of mice in the four experimental groups and the blank control group. *** indicates p < 0.001 between the experimental group and the blank group. DETAILED DESCRIPTION

[0025] The present invention will be described in further detail below with reference to the accompanying drawings.

[0026] Example 1:

[0027] The preparation methods of the four different nanomaterials include the following steps:

[0028] 1) Take the water extract of goose grass and adjust its pH value to 6 with hydrochloric acid or sodium hydroxide solution, then add 6mmol / L silver nitrate solution according to the volume ratio of goose grass water extract to silver nitrate solution of 1:3, and let it react for 15h to obtain dark brown silver nanoparticle colloid AgNP S solution;

[0029] Prepare a 33 mg / mL 2-methylimidazole solution with methanol as the solvent; then prepare a 30 mg / mL zinc nitrate solution with deionized water as the solvent. Ultrasonicate the two solutions until they are completely dissolved. Quickly add the zinc nitrate solution to the 2-methylimidazole solution under magnetic stirring. The mixed solution gradually changes from colorless to milky white. Stir thoroughly for 15 minutes to mix evenly and then let it stand for 24 hours. Centrifuge the obtained ZIF-8 solution at 10,000 rpm for 30 minutes, discard the supernatant, wash the product with methanol three times, and dry it in a 50°C vacuum drying oven for 24 hours to obtain white ZIF-8 powder.

[0030] 2) According to the molar ratio of zinc nitrate hexahydrate to 2-methylimidazole being 1:8 and the mass ratio of curcumin (Cur) to 2-methylimidazole solution being 1:60, zinc nitrate hexahydrate, 2-methylimidazole and curcumin were taken respectively, and then the zinc nitrate hexahydrate was fully dissolved in ultrapure water by ultrasonication to obtain a zinc nitrate solution with a zinc ion concentration of 0.08 mol / L. Curcumin (Cur) and 2-methylimidazole solution were fully dissolved in anhydrous methanol by ultrasonication to obtain a 2-methylimidazole solution containing curcumin with a Cur concentration of 500 μg / mL. The zinc nitrate solution was quickly added to the 2-methylimidazole solution containing curcumin under magnetic stirring, stirred evenly and allowed to stand for 24 hours to obtain a ZIF-8@Cur solution;

[0031] 3) According to ZIF-8@Cur and AgNP S AgNPs were added to the ZIF-8@Cur solution at a volume ratio of 15:1. S , ZIF-8@Cur&AgNP was prepared after ultrasonic mixing S Nanocomposite solution; the reacted nanocomposite solution was centrifuged at 8000 rpm for 30 min to collect the precipitate and redisperse it in methanol. After repeated washing, the supernatant was discarded and the obtained product was dried in a vacuum drying oven at 40 ° C for 36 h to obtain orange ZIF-8@Cur&AgNP S Nanocomposite materials.

[0032] Figure 1 and Figure 2The four different nanomaterials prepared are given (a: AgNP S ;b:ZIF-8; c:ZIF-8@Cur; d:ZIF-8@Cur&AgNP S )’s apparent morphology and particle size distribution, the characterization steps are as follows:

[0033] The morphology of the four different nanomaterials was observed using a FEI Tecnai G2 F20 STWIN transmission electron microscope. S Black powder (ultrapure water as solvent) and vacuum-dried ZIF-8, ZIF-8@Cur, ZIF-8@Cur&AgNP S The powder (with anhydrous ethanol as the solvent) was diluted to a certain proportion and ultrasonicated in cold water for about 10 minutes. One drop of the fully dissolved solution was then dropped onto a 400-mesh copper grid to allow the solvent to fully evaporate at room temperature. The voltage parameter of the TEM was set to 80 kV, and the micromorphology and particle size of the four different nanomaterials were photographed and observed.

[0034] like Figure 1 As shown in a, AgNPs synthesized from the aqueous extract of Glechoma longituba S They are all nearly spherical, and the diameter of the nanoparticles is about 20nm. In addition, it can be observed that AgNP S The dispersion of the black silver nanoparticles is good, and the surface of the black silver nanoparticles is not very smooth. It is speculated that the light gray substance attached to it is the active ingredient from the water extract, which is used to overcome the disadvantage of the nanoparticles being easily aggregated and enhance the stability and dispersion of the nanoparticles; Figure 1 b, c, and d show three nanomaterials ZIF-8@Cur&AgNP S All of them showed a regular dodecahedron shape, and the nanocrystals were evenly distributed. The diameter of blank ZIF-8 nanoparticles was about 70nm, while that of ZIF-8@Cur and ZIF-8@Cur&AgNP was about 70nm. S The diameters of Cur and AgNP are slightly larger than those of ZIF-8, which are about 75nm and 80nm respectively. S All of them have been successfully encapsulated in ZIF-8 carriers.

[0035] It is worth noting that compared with the regular dodecahedron morphology of ZIF-8 carrier, ZIF-8@Cur and ZIF-8@Cur&AgNP SThe crystal morphology of the latter two seems to have undergone some changes. The edges of the crystal morphology of the latter two are obviously not as clear as the blank ZIF-8 carrier, and the particle sizes of their nanoparticles are slightly different. It is speculated that this may be due to the fact that during the one-pot synthesis process, the stirring speed and temperature affect the crystal growth process, resulting in the non-uniform distribution of Cur in the carrier material, causing its morphology to change; due to the one-step synthesis method, Cur may interact with the ZIF-8 precursor during the early mixing process, interfering with its normal growth; in addition, the ZIF-8 material has certain flexibility, and the loaded Cur and AgNP S Both may introduce internal stress and cause structural collapse of part of the skeleton, thus affecting its morphological characteristics. Since Ag is a heavy element, its ability to scatter electron beams is stronger than that of light elements such as C, O, and N. Therefore, it will show darker black high-contrast spots than ZIF-8 and ZIF-8@Cur in the transmission electron microscope. Figure 1 AgNPs can be seen in d S The nanostructured particles were loaded into ZIF-8 in the form of monodisperse spherical particles.

[0036] The average hydrated particle size distribution and polydispersity index of four different nanomaterials were measured using Litesizer 500 nanometer particle size analyzer and Zeta potential analyzer. The temperature of Malvern particle size analyzer was set at 25℃, and the prepared nanomaterial solutions were diluted to a certain multiple (AgNP S The colloidal solution used ultrapure water as solvent, ZIF-8, ZIF-8@Cur, ZIF-8@Cur&AgNP S The nano-solution (using anhydrous ethanol as solvent) was ultrasonicated in cold water for 10 min, and 1 ml was taken and placed in a cuvette for measurement.

[0037] like Figure 2 As shown in a, AgNP S The average hydrated particle size is 52.07±0.86nm; the PDI is 0.25±0.01, indicating that the generated nanoparticles have good dispersion. However, the particle size measured by the nanoparticle size analyzer is slightly larger than the test result of TEM. This may be due to the different detection methods and principles of the two. The nanoparticle size analyzer is more used to reveal the hydrodynamic diameter of the sample particles and the particle size distribution of the hydrated particles. Some other components adsorbed on the surface of the silver nanoparticles in the aqueous solution may cause the measurement results to be higher, resulting in a certain deviation from the particle size observed by transmission electron microscopy; Figure 2 As shown in b, c and d, ZIF-8, ZIF-8@Cur, ZIF-8@Cur&AgNP SThe average hydrated particle sizes of the three materials were 107.57±0.63nm, 155.01±0.22nm and 156.68±1.14nm, respectively; the PDIs were 0.072±0.018, 0.232±0.028 and 0.244±0.017, respectively. The particle sizes of the three materials were basically consistent with the trends observed by transmission electron microscopy, but due to the presence of agglomeration or solvation effects, the overall measured values were larger than their actual sizes. The PDI results showed that: ZIF-8@Cur and ZIF-8@Cur&AgNP S The dispersion performance of the ZIF-8 carrier is lower than that of the blank ZIF-8 carrier, but it can still be uniformly dispersed in the solvent.

[0038] By determining the four nanomaterials (AgNP S , ZIF-8, ZIF-8@Cur, ZIF-8@Cur&AgNP S ) and cytotoxicity to explore its in vitro biocompatibility, the test steps are as follows:

[0039] Weigh 10 mg of freeze-dried AgNPs S Powder and vacuum-dried ZIF-8, ZIF-8@Cur, ZIF-8@Cur&AgNP S The powder was dissolved in 10 mL of normal saline and sonicated until completely dissolved to prepare a 1 mg / mL stock solution. Before the experiment, the stock solution was sonicated and diluted with normal saline to a final concentration of 200 μg / mL for each sample solution.

[0040] Take anticoagulated whole blood and centrifuge it at 4000rpm for 15min. After discarding the supernatant, add normal saline, gently blow the cell suspension evenly, centrifuge it at 4000rpm for 10min, wash the red blood cells, repeat this step until the supernatant is clear, and discard the normal saline. Pipette 40μL of red blood cells into each centrifuge tube, add 1mL of each prepared sample solution to each tube, and set up positive and negative control groups. The positive control is 1mL of deionized water, and the negative control is 1mL of normal saline. All groups were incubated in a 37℃ incubator for 1h, and three parallel wells were set up for each group. After incubation, observe the hemolysis of the cells. After centrifugation for 5min, aspirate 100μL of the supernatant into a 96-well plate, measure the OD value at a wavelength of 545nm, and calculate the relative hemolysis rate of each sample according to the formula. The absorbance of the sample is recorded as Ds, the absorbance of the normal saline group is recorded as Dnc, and the absorbance of the deionized water group is recorded as Dpc. The relative hemolysis rate (%) = (Ds-Dnc) / (Dpc-Dnc)×100%.

[0041] L929 fibroblasts were selected and the CCK-8 method was used to determine the in vitro cytotoxicity of each nanomaterial at a concentration of 200 μg / mL. L929 cells were seeded in 96-well plates at a seeding density of 10 4 cells·well -1 , add 100 μL to each well. After incubation in a cell culture incubator containing 5% carbon dioxide and 37°C for 24 hours, 10 μL of each prepared sample solution was respectively aspirated and placed in each well containing cells, and the drug and cells were incubated together for another 24 hours. A group of cells without sample was set up as a parallel control group. The experiment was repeated three times, and three parallel wells were set up for each group. After adding 10 μL of CCK-8 solution to each well, the culture was continued for about 1 hour, and the absorbance of each well at a wavelength of 450 nm was measured, and the wound healing rate was calculated according to the formula. The OD value of the experimental group was recorded as ODex, the OD value of the control group was recorded as ODcg, and the background OD value was recorded as ODbg. The relative cell viability (%) = (ODex-ODbg) / (ODcg-ODbg)×100%.

[0042] According to the current general classification standard (ISO 10993-4 specification), when the hemolysis rate is less than 5%, it can be considered that the material has good blood compatibility and can be used in biomedical research. The hemolysis rate of each sample is quantitatively determined, such as Figure 3 As shown, 200 μg / mL of AgNP S , ZIF-8, ZIF-8@Cur and ZIF-8@Cur&AgNP S The hemolysis rates of the four nanomaterials were all much less than 5%, and compared with single drug use, combined use could significantly reduce the hemolysis rate.

[0043] The relative cell viability assay results were as follows Figure 4 As shown in the figure, among the several nanomaterials, ZIF-8 had the highest toxicity when acting on fibroblasts, with a relative cell viability of only 29.22%; the cell viability of ZIF-8@Cur was 96.03%; AgNP S The relative cell viability was 88.55% when it was used alone. After combining it with ZIF-8@Cur, most of the AgNPs S The silver nanoparticles are stably loaded in the pore structure of ZIF-8, and the number of silver nanoparticles in direct contact with cells is reduced, so the composite material ZIF-8@Cur&AgNP S The cell survival rate was as high as 96.89%. The experimental results showed that: AgNP S Compared with ZIF-8@Cur, ZIF-8@Cur&AgNP S All of them have good biocompatibility and are suitable for use as nano-antibacterial materials in wound healing experiments in mice.

[0044] To evaluate the healing effects of various nanomaterials on bacterially infected wounds, the following steps were performed:

[0045] Six-week-old male Kunming white mice were used, each weighing approximately 20-25 g. After purchase, the mice were individually labeled and housed in separate cages, with free access to standard mouse chow and drinking water. To avoid individual differences, all model mice were randomly divided into the following five groups: blank group, AgNP group, S group, ZIF-8@Cur group, ZIF-8@Cur&AgNP S After an adaptation period, all animals were anesthetized with an intraperitoneal injection of 1% sodium pentobarbital. The hair on the back of the neck was shaved, and the skin on the back of the mouse was wiped with alcohol. A sterile punch was used to create a circular wound of approximately 6 mm on the back of the mouse. Then, 20 μL of Staphylococcus aureus (1×10 7 CFU·mL -1 )Build an infection model.

[0046] The wound was recorded as the first day, and each group of mice was fed at room temperature according to the same standard. The blank group wounds were not treated in any way. The experimental groups were sprayed with different materials (200 μg / mL) and placed in cages after complete absorption (the light group irradiated the wound with blue light for about 15 minutes after administration). The treatment was given once a day in the morning and evening. On the 3rd, 7th and 14th days, the changes in the back wounds of the mice were observed and photographed, and the wound healing rate was calculated according to the formula. The area of the back wound of the mouse on the first day was recorded as X, and the area of the back wound on the 3rd, 7th and 14th days was recorded as Xi, then the wound healing rate (%) = (Xi-X) / X×100%.

[0047] Figure 5 AgNP S , ZIF-8@Cur, ZIF-8@Cur&AgNP S (L + ), ZIF-8@Cur&AgNP S (L - ) The skin wound healing rates of mice in the four experimental groups and the blank control group. Figure 5 As shown in the figure, on the third day, the wound healing rate of the blank group was only about 20%, while that of the AgNP group was S The healing rate of the blank group reached about 40%, the healing rate of the ZIF-8@Cur and the non-light-exposed group was about 45%, and the healing rate of the combined photodynamic therapy group reached more than 50%. On the 7th day, the healing rate of the blank group reached about 50%, and the healing rate of the AgNP SThe healing rates of the ZIF-8@Cur, ZIF-8@Cur, and combination therapy groups without light exposure ranged from 65-75%, while the combined therapy and photodynamic therapy group achieved a high healing rate of 88%. On day 14, the wound healing rate in the blank group was approximately 80%, while that in the combined therapy and photodynamic therapy group reached over 95%. The healing rates of the ZIF-8@Cur and combination therapy groups without light exposure were also close to 90%, demonstrating a significant difference compared to the blank group.

[0048] By comparing the wound healing rates of different groups, it was shown that the AgNP S Combined with ZIF-8-encapsulated Cur, AgNP can effectively promote the healing of bacterial-infected wounds. S The antibacterial properties of Cur enable it to effectively inhibit the growth of Staphylococcus aureus in wounds, reducing the risk of wound infection. Cur's anti-inflammatory and antioxidant activities help alleviate inflammatory responses at the wound site, scavenging excess free radicals and creating a microenvironment conducive to tissue repair. Encapsulating Cur in ZIF-8 improves its water solubility and stability, achieving a sustained release effect, extending its duration of action at the wound site and enhancing the therapeutic effect. Furthermore, this nanocomposite material can avoid the risk of secondary damage to damaged tissue caused by traditional wound dressings, such as gauze, during dressing changes.

[0049] Example 2:

[0050] 1) Take the water extract of goose grass and adjust its pH value to 8 with hydrochloric acid or sodium hydroxide solution, then add 4mmol / L silver nitrate solution according to the volume ratio of goose grass water extract to silver nitrate solution of 1:6, and let it react for 10 hours to obtain dark brown silver nanoparticle colloid AgNP S solution;

[0051] 2) According to the molar ratio of zinc nitrate hexahydrate to 2-methylimidazole being 1:10 and the mass ratio of curcumin (Cur) to 2-methylimidazole solution being 1:50, zinc nitrate hexahydrate, 2-methylimidazole and curcumin were taken respectively, and then the zinc nitrate hexahydrate was fully dissolved in ultrapure water by ultrasonication to obtain a zinc nitrate solution with a zinc ion concentration of 0.05 mol / L. Curcumin (Cur) and 2-methylimidazole solution were fully dissolved in anhydrous methanol by ultrasonication to obtain a 2-methylimidazole solution containing curcumin with a Cur concentration of 400 μg / mL. The zinc nitrate solution was quickly added to the 2-methylimidazole solution containing curcumin under magnetic stirring, stirred evenly and allowed to stand for 18 hours to obtain a ZIF-8@Cur solution;

[0052] 3) According to ZIF-8@Cur and AgNP S AgNPs were added to the ZIF-8@Cur solution at a volume ratio of 10:1. S, ZIF-8@Cur&AgNP was prepared after ultrasonic mixing S Nanocomposite solution; the reacted nanocomposite solution was centrifuged at a speed of 10000 rpm for 15 min to collect the precipitate and redisperse it in methanol. After repeated washing, the supernatant was discarded and the obtained product was dried in a vacuum drying oven at 50 ° C for 24 h to obtain orange ZIF-8@Cur&AgNP S Nanocomposite materials.

[0053] Example 3:

[0054] 1) Take the water extract of goose grass and adjust its pH value to 5 with hydrochloric acid or sodium hydroxide solution, then add 5mmol / L silver nitrate solution according to the volume ratio of goose grass water extract to silver nitrate solution of 1:9, and let it react for 3 hours to obtain dark brown silver nanoparticle colloid AgNP S solution;

[0055] 2) According to the molar ratio of zinc nitrate hexahydrate to 2-methylimidazole being 1:5 and the mass ratio of curcumin (Cur) to 2-methylimidazole solution being 1:80, zinc nitrate hexahydrate, 2-methylimidazole and curcumin were taken respectively, and then the zinc nitrate hexahydrate was fully dissolved in ultrapure water by ultrasonication to obtain a zinc nitrate solution with a zinc ion concentration of 0.1 mol / L. Curcumin (Cur) and 2-methylimidazole solution were fully dissolved in anhydrous methanol by ultrasonication to obtain a 2-methylimidazole solution containing curcumin with a Cur concentration of 300 μg / mL. The zinc nitrate solution was quickly added to the 2-methylimidazole solution containing curcumin under magnetic stirring, stirred evenly and allowed to stand for 30 hours to obtain a ZIF-8@Cur solution;

[0056] 3) According to ZIF-8@Cur and AgNP S AgNPs were added to the ZIF-8@Cur solution at a volume ratio of 20:1. S , ZIF-8@Cur&AgNP was prepared after ultrasonic mixing S Nanocomposite solution; the reacted nanocomposite solution was centrifuged at a speed of 12000 rpm for 20 min to collect the precipitate and redisperse it in methanol. After repeated washing, the supernatant was discarded and the obtained product was dried in a vacuum drying oven at 45 ° C for 30 h to obtain orange ZIF-8@Cur&AgNP S Nanocomposite materials.

[0057] Example 4:

[0058] 1) Take the water extract of goose grass and adjust its pH value to 7 with hydrochloric acid or sodium hydroxide solution, then add 8mmol / L silver nitrate solution according to the volume ratio of goose grass water extract to silver nitrate solution of 1:1, and let it react for 8 hours to obtain dark brown silver nanoparticle colloid AgNPS solution;

[0059] 2) According to the molar ratio of zinc nitrate hexahydrate to 2-methylimidazole being 1:6 and the mass ratio of curcumin (Cur) to 2-methylimidazole solution being 1:70, zinc nitrate hexahydrate, 2-methylimidazole and curcumin were taken respectively, and then the zinc nitrate hexahydrate was fully dissolved in ultrapure water by ultrasonication to obtain a zinc nitrate solution with a zinc ion concentration of 0.15 mol / L. Curcumin (Cur) and 2-methylimidazole solution were fully dissolved in anhydrous methanol by ultrasonication to obtain a 2-methylimidazole solution containing curcumin with a Cur concentration of 600 μg / mL. The zinc nitrate solution was quickly added to the 2-methylimidazole solution containing curcumin under magnetic stirring, stirred evenly and allowed to stand for 12 hours to obtain a ZIF-8@Cur solution;

[0060] 3) According to ZIF-8@Cur and AgNP S AgNPs were added to the ZIF-8@Cur solution at a volume ratio of 30:1. S , ZIF-8@Cur&AgNP was prepared after ultrasonic mixing S Nanocomposite solution; the reacted nanocomposite solution was centrifuged at 9000 rpm for 25 min to collect the precipitate and redisperse it in methanol. After repeated washing, the supernatant was discarded and the obtained product was dried in a vacuum drying oven at 55 ° C for 18 h to obtain orange ZIF-8@Cur&AgNP S Nanocomposite materials.

[0061] Example 5:

[0062] 1) Take the water extract of goose grass and adjust its pH value to 9 with hydrochloric acid or sodium hydroxide solution, then add 7mmol / L silver nitrate solution according to the volume ratio of goose grass water extract to silver nitrate solution of 1:7, and let it react for 12 hours to obtain dark brown silver nanoparticle colloid AgNP S solution;

[0063] 2) According to the molar ratio of zinc nitrate hexahydrate to 2-methylimidazole of 1:12 and the mass ratio of curcumin (Cur) to 2-methylimidazole solution of 1:65, zinc nitrate hexahydrate, 2-methylimidazole and curcumin were taken respectively, and then the zinc nitrate hexahydrate was fully dissolved in ultrapure water by ultrasonication to obtain a zinc nitrate solution with a zinc ion concentration of 0.12 mol / L. Curcumin (Cur) and 2-methylimidazole solution were fully dissolved in anhydrous methanol by ultrasonication to obtain a 2-methylimidazole solution containing curcumin with a Cur concentration of 700 μg / mL. The zinc nitrate solution was quickly added to the 2-methylimidazole solution containing curcumin under magnetic stirring, stirred evenly and allowed to stand for 36 hours to obtain a ZIF-8@Cur solution;

[0064] 3) According to ZIF-8@Cur and AgNP S AgNPs were added to the ZIF-8@Cur solution at a volume ratio of 1:1. S , ZIF-8@Cur&AgNP was prepared after ultrasonic mixing S Nanocomposite solution; the nanocomposite solution after the reaction was centrifuged at a speed of 15000 rpm for 10 min to collect the precipitate and redisperse it in methanol. After repeated washing, the supernatant was discarded and the obtained product was dried in a vacuum drying oven at 60 ° C for 12 h to obtain orange ZIF-8@Cur&AgNP S Nanocomposite materials.

Claims

1. A method for preparing a nanocomposite material, characterized in that The following steps are involved: 1) taking an aqueous extract of the herbaceous plant and adjusting its pH to 5-9, then adding a 4-8 mmol / L silver nitrate solution to the aqueous extract of the herbaceous plant at a volume ratio of 1:1-9, and allowing the solution to react to obtain a dark brown colloidal solution of silver nanoparticles; 2) zinc nitrate hexahydrate, 2-methylimidazole, and curcumin are taken separately at a molar ratio of zinc nitrate hexahydrate to 2-methylimidazole of 1:4-12 and a mass ratio of curcumin (Cur) to 2-methylimidazole solution of 1:50-80. The zinc nitrate hexahydrate, 2-methylimidazole, and curcumin are then ultrasonically dissolved in ultrapure water to obtain a zinc nitrate solution having a zinc ion concentration of 0.05-0.15 mol / L. Curcumin (Cur) and 2-methylimidazole solution are ultrasonically dissolved in anhydrous methanol to obtain a curcumin-containing 2-methylimidazole solution having a Cur concentration of 300-700 μg / mL. The zinc nitrate solution is rapidly added to the curcumin-containing 2-methylimidazole solution under magnetic stirring, stirred evenly, and allowed to stand to obtain a ZIF-8@Cur solution. 3) According to ZIF-8@Cur and AgNP S Add AgNPs to the ZIF-8@Cur solution at a volume ratio of 1 to 30:

1. S , ZIF-8@Cur&AgNP was prepared after ultrasonic mixing S Nanocomposite solution; the nanocomposite solution after the reaction was centrifuged at high speed, the precipitate was collected and redispersed in methanol, and the supernatant was discarded after repeated washing. The obtained product was fully dried in a vacuum drying oven to obtain orange ZIF-8@Cur&AgNP S Nanocomposite materials.

2. The method for preparing the nanocomposite material according to claim 1, wherein: The pH value of the water extract of the herb is adjusted by using hydrochloric acid or sodium hydroxide solution.

3. The method for preparing the nanocomposite material according to claim 1, wherein: The static reaction time in step 1) is 3 to 15 hours.

4. The method for preparing the nanocomposite material according to claim 1, wherein: The standing time in step 2) is 12 to 36 hours.

5. The method for preparing the nanocomposite material according to claim 1, wherein: In the step 3), the centrifugal speed is 8000-15000 rpm, and the centrifugal time is 10-30 min.

6. The method for preparing the nanocomposite material according to claim 1, wherein: In the step 3), the vacuum drying temperature is 40-60° C., and the drying time is 12-36 hours.

7. A ZIF-8@Cur&AgNP prepared by the method according to any one of claims 1 to 6 S Application of nanocomposites in promoting healing of bacterially infected wounds.

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