Nano composite material with photo-thermal antibacterial, ROS (reactive oxygen species) removal and wound healing promotion effects and preparation method of nano composite material

Abstract

The invention relates to a nano composite material with photo-thermal antibacterial property, ROS (reactive oxygen species) removal capability and capability of promoting wound healing and a preparation method of the nano composite material. The nano composite material is MnPB (at) PDA, and is formed by taking manganese ion doped Prussian blue nano cube MnPB as an inner core and wrapping the periphery of the inner core with polydopamine PDA. The average size of the nano composite material is 115-245 nm, the average size of the inner core MnPB is 95-200 nm, and the average thickness of the PDA shell layer is 10-23 nm. The preparation method comprises the following steps: (1) preparing MnPB by adopting a precipitation method; and (2) coating the PDA shell layer formed by dopamine auto-polymerization on the surface of the MnPB by adopting an in-situ polymerization method. The preparation process is simple, the product morphology is uniform, the controllability of composition and size is good, the product nano composite material has excellent photo-thermal antibacterial performance, good active oxygen species removal capacity and wound healing treatment effect, the antibacterial performance can be remarkably improved by adsorbing Cu < 2 + > or Zn < 2 + > ions, and the application prospect is wide. Good application prospects are realized in the treatment fields of photo-thermal antibiosis, ROS (reactive oxygen species) removal and wound healing promotion.

Description

Technical Field

[0001] The present invention relates to the technical field of nanomaterial preparation, and in particular to a nanocomposite material with enhanced photothermal antibacterial, ROS scavenging and wound healing promoting effects and a preparation method thereof. Background Art

[0002] With the emergence of superbugs and the formation of bacterial biofilms, antibacterial infection treatment has become increasingly difficult. Under this trend, relying solely on antibiotics and the body's immune system to treat stubborn bacteria is very limited. On the other hand, poor healing of skin wounds or surgical wounds can easily lead to postoperative complications. The injured tissue is prone to produce excessive reactive oxygen species (ROS) such as hydroxyl free radicals and superoxide free radicals. The production of excessive ROS will inhibit cell proliferation and cause cell apoptosis through oxidative reactions. The continuous oxidation of ROS to the tissue at the wound site will damage fibroblasts and keratinocytes, etc., resulting in delayed wound healing and an increased risk of bacterial infection of the wound. Therefore, it is necessary to use exogenous materials to remove excess ROS at the wound in a timely manner to promote wound healing and restore tissue function.

[0003] Prussian blue nanoparticles are a type of photothermal material that strongly absorbs long-wave visible light and near-infrared light. They can effectively convert near-infrared light energy into heat, using high temperature to destroy the normal physiological functions of bacteria to achieve a photothermal antibacterial effect, thereby reducing the body's inflammation caused by bacterial infection. At the same time, Prussian blue nanoparticles also have excellent multiple nanoenzyme activities and anti-inflammatory properties, and have application potential as ROS scavengers in promoting wound healing. The literature (Theranostics, 2019, 9, 2843-2855) reported that Mn 2+ Doped Prussian blue manganese nanozymes have the function of scavenging various ROS and can be used to treat colitis in mice. Patent (CN105412927A) provides Mn nanozymes that can be used for photothermal therapy. 2+ Preparation method of doped Prussian blue nanomaterials. However, how to obtain a composite material with enhanced photothermal antibacterial properties, ROS scavenging and wound healing promotion is still a challenge, which will provide a new method for the integrated solution of the clinical medical problem of wound healing caused by bacterial infection. Polydopamine (PDA) has excellent biocompatibility, ROS scavenging ability, strong metal ion chelating ability and light absorption ability, and is widely used to construct photothermal materials and biological antibacterial agents. Therefore, using PDA and Mn 2+ Nanocomposites constructed with doped Prussian blue nanoparticles are expected to have the effects of photothermal antibacterial, ROS scavenging and promoting wound healing. By further chelating copper, zinc and other ions with antibacterial activity using PDA, the enhancement of antibacterial function can be achieved simply and conveniently. Summary of the Invention

[0004] The purpose of the present invention is to solve the deficiencies of the prior art and provide a nanocomposite material MnPB@PDA composed of Prussian blue nanocubes doped with manganese ions and a preparation method thereof. The nanocomposite material has a core-shell structure, wherein the core manganese ion-doped Prussian blue nanocubes MnPB are superior to Prussian blue nanoparticles in ROS scavenging ability, and the PDA shell layer wrapped around the periphery can not only effectively improve the light absorption capacity, photothermal effect and ROS scavenging effect of MnPB, but also can absorb copper ions Cu and improve the ROS scavenging ability of MnPB. 2+ or zinc ion Zn 2+ The enhanced antibacterial effect is achieved. Therefore, the nanocomposite material achieves the application effect of integrating photothermal antibacterial, ROS removal and wound healing promotion.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] The present application provides a nanocomposite material MnPB@PDA containing Prussian blue nanocubes doped with manganese ions. The nanocomposite material MnPB@PDA is composed of a core of Prussian blue nanocubes MnPB doped with manganese ions and a PDA shell layer wrapped around the periphery.

[0007] In some embodiments, the surface of the nanocomposite material can further adsorb copper ions Cu 2+ or zinc ion Zn 2 + .

[0008] In some embodiments, the copper ions Cu adsorbed by the nanocomposite 2+ or zinc ion Zn 2+ , which can come from any one of copper acetate, copper sulfate, copper chloride, zinc acetate, zinc sulfate, and zinc chloride.

[0009] In some embodiments, the nanocomposite has an average particle size of 115 to 245 nm, wherein the average size of the MnPB core is 95 to 200 nm, and the average thickness of the PDA shell is 10 to 23 nm.

[0010] In some embodiments, the nanocomposite material can be simultaneously applied to photothermal antibacterial, reactive oxygen species scavenging and wound healing treatments.

[0011] Some embodiments of the present application provide a method for preparing a nanocomposite material, which is carried out according to the following steps:

[0012] (1) Preparation of manganese ion-doped Prussian blue nanocubes (MnPB): Solution A was prepared by dissolving a certain amount of manganese acetate tetrahydrate and ferrous sulfate heptahydrate in 20 mL of 0.01 mol / L hydrochloric acid. Solution B was prepared by dissolving 1.0 g of polyvinyl pyrrolidone and a certain amount of potassium hexacyanoferrate (III) in 20 mL of water. Solution A was added dropwise to solution B with stirring, and then stirring was stopped. The temperature was raised to 90°C and the reaction was continued for 5 h. The mother liquor was removed by centrifugation, and the solution was washed five times with ethanol and five times with water, respectively, and then dried in vacuo at 40°C to obtain MnPB.

[0013] (2) PDA shell coating of MnPB: 8 mg of the MnPB prepared in step (1) and 8 mL of water were added to a reaction flask. After the reaction mixture was uniformly mixed, 8 mL of Tris-HCl buffer (0.01 mol / L, pH 7.9) containing dopamine hydrochloride was added dropwise to the reaction flask. The reaction was stirred at room temperature for 12 h to complete the PDA shell coating of MnPB. The mixture was centrifuged to remove the supernatant, washed with water five times, and then dried in vacuo at 40°C to obtain a MnPB@PDA nanocomposite material.

[0014] In some embodiments, in the method for preparing the nanocomposite material, the concentrations of manganese acetate and ferrous sulfate contained in solution A in step (1) are 0.05 mol / L to 0.5 mol / L, and the concentration of potassium hexacyanoferrate (III) contained in solution B is 0.1 mol / L to 1.0 mol / L.

[0015] In some embodiments, in the method for preparing the nanocomposite material, the concentration of dopamine hydrochloride in the Tris-HCl buffer in step (2) is 0.0026 mol / L to 0.053 mol / L.

[0016] In some embodiments, in the method for preparing the nanocomposite material, the mass ratio of MnPB to dopamine hydrochloride in step (2) is 1:0.5 to 1:20.

[0017] The nanocomposite material MnPB@PDA proposed in the present invention has antibacterial activity under near-infrared light, good ROS scavenging ability and skin healing therapeutic function, and has good application prospects in antibacterial and skin healing treatment.

[0018] Due to the adoption of the above technical solution, the present invention has the following advantages and positive effects compared with the existing inventions:

[0019] (1) The nanocomposite material MnPB@PDA prepared by the present invention has good antibacterial properties, ROS scavenging ability and skin healing promoting effect. The PDA wrapping can make the performance of MnPB@PDA in photothermal antibacterial, ROS scavenging and skin healing promoting significantly enhanced compared with MnPB; at the same time, the use of PDA to Cu2+ or Zn 2+ The chelation effect adsorbed Cu 2+ or Zn 2+ The bactericidal ability of ionic MnPB@PDA is significantly enhanced, and it can completely kill bacteria at lower concentrations and in shorter illumination time, making it more suitable for safe and rapid antibacterial applications.

[0020] (2) The preparation process of the present invention is simple and easy. The size of the nanocomposite material and the thickness of the PDA shell can be conveniently adjusted by adjusting the amount of reactants. The obtained nanocomposite material has a regular morphology. The entire preparation process does not require additives such as stabilizers or surfactants, thereby avoiding the negative impact of additives on the application of the material in biological systems.

[0021] (3) The PDA shell in the nanocomposite material MnPB@PDA prepared by the present invention also has the ability to load drugs such as antibiotics or couple other functional molecules, which provides convenience for subsequent surface loading of other drug molecules or covalent modification of functional molecules and expansion of application performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a transmission electron microscope image of the product of Example 1.

[0023] Figure 2 This is a transmission electron microscope image of the product of Example 4.

[0024] Figure 3 This is the element distribution diagram of the product of Example 4.

[0025] Figure 4 It is the absorption spectrum figure of the product of Example 1 and Example 4.

[0026] Figure 5 Graph showing temperature changes of the products of Example 1 and Example 4 under near-infrared light.

[0027] Figure 6 This is a temperature change diagram of the product of Example 4 under near-infrared light of different power densities.

[0028] Figure 7 This is a temperature change diagram of the product of Example 4 during the illumination-cooling cycle test.

[0029] Figure 8 Transmission electron microscope image of the product of Example 8

[0030] Figure 9 This is the element distribution diagram of the product of Example 8.

[0031] Figure 10 This is the Cu 2p X-ray photoelectron spectrum of the product of Example 8.

[0032] Figure 11 It is the absorption spectrum figure of the product of Example 4 and Example 8.

[0033] Figure 12 This is a temperature change diagram of the dispersion of the product of Example 8 during the illumination-cooling cycle test.

[0034] Figure 13 This is a diagram of the antibacterial effect of the product of Example 2 under darkness and near-infrared light.

[0035] Figure 14 These are graphs showing the antibacterial effects of the products of Example 1, Example 4, and Example 8 under darkness and near-infrared light.

[0036] Figure 15 The figures show the antibacterial effects of the product of Example 8 at different concentrations under near-infrared light.

[0037] Figure 16 This is a diagram showing the efficiency of the products of Example 1 and Example 4 in scavenging hydroxyl radicals.

[0038] Figure 17 This is a diagram showing the efficiency of the products of Example 1 and Example 4 in scavenging superoxide radicals. DETAILED DESCRIPTION

[0039] In the present invention, a MnPB@PDA nanocomposite is prepared by a two-step reaction of precipitation and in-situ polymerization and encapsulation. The size of MnPB is regulated by changing the concentration of the reactants manganese acetate, ferrous sulfate, and potassium hexacyanoferrate (III), and the thickness of the PDA shell is regulated by changing the concentration of dopamine hydrochloride. Compared with MnPB, the obtained MnPB@PDA nanocomposite has enhanced photothermal antibacterial effect, improved ROS scavenging ability, and faster skin healing. In particular, the adsorption of Cu 2+ or Zn 2+ The antibacterial ability of the ionic nanocomposite material is further enhanced, and the bacteria can be completely killed in a shorter illumination time.

[0040] The following examples and drawings are used to further illustrate the content of the present invention, but the content of the present invention is not limited to the following examples.

[0041] Example 1:

[0042] Manganese-doped Prussian blue nanocubes (MnPB) were prepared as follows: 2.45 g of manganese acetate tetrahydrate and 2.78 g of ferrous sulfate heptahydrate were dissolved in 20 mL of 0.01 mol / L hydrochloric acid to prepare solution A, where the concentrations of manganese acetate and ferrous sulfate were both 0.5 mol / L. 1.0 g of polyvinyl pyrrolidone and 6.58 g of potassium hexacyanoferrate (III) were dissolved in 20 mL of water to prepare solution B, where the concentration of potassium hexacyanoferrate (III) was 1.0 mol / L. Solution A was added dropwise to solution B with stirring, and then stirring was turned off. The temperature was raised to 90°C and the reaction was allowed to react for 5 h. The mother liquor was removed by centrifugation, and the solution was washed five times with ethanol and five times with water, respectively, before being dried in vacuo at 40°C to obtain MnPB.

[0043] Figure 1 The morphology of MnPB observed under a transmission electron microscope is shown in Figure 1. The particles have a cubic morphology and an average size of 200 nm.

[0044] Example 2:

[0045] The steps and processes are the same as those in Example 1, except that in step (1), 1.23 g of manganese acetate tetrahydrate and 1.39 g of ferrous sulfate heptahydrate are used in solution A, corresponding to a concentration of 0.25 mol / L of manganese acetate and ferrous sulfate, and 3.29 g of potassium hexacyanoferrate (III) is used in solution B, corresponding to a concentration of 0.5 mol / L of potassium hexacyanoferrate (III), to obtain manganese-doped Prussian blue nanocubes MnPB. The product has a cubic morphology with an average size of 150 nm as observed under a transmission electron microscope.

[0046] Example 3:

[0047] The steps and processes are the same as those in Example 1, except that in step (1), 0.25 g of manganese acetate tetrahydrate and 0.28 g of ferrous sulfate heptahydrate are used in solution A, corresponding to the concentrations of manganese acetate and ferrous sulfate of 0.05 mol / L, and 0.66 g of potassium hexacyanoferrate (III) is used in solution B, corresponding to the concentration of potassium hexacyanoferrate (III) of 0.1 mol / L, to obtain manganese-doped Prussian blue nanocubes MnPB. The product has a cubic morphology with an average size of 95 nm as observed under a transmission electron microscope.

[0048] Example 4:

[0049] The PDA-wrapped nanocomposite material MnPB@PDA was prepared according to the following steps: 8 mg of the product MnPB of Example 1 and 8 mL of water were added to a reaction flask. After the reaction was evenly mixed, 80 mg of dopamine hydrochloride was dissolved in 8 mL of Tris-HCl buffer (0.01 mol / L, pH 7.9), and the corresponding dopamine hydrochloride solution concentration was 0.052 mol / L. The mixture was then added dropwise to the reaction flask. The reaction was stirred at room temperature for 12 h to complete the wrapping of the MnPB by the PDA shell. The mixture was centrifuged to remove the supernatant, washed with water 5 times, and then dried in vacuo at 40°C to obtain the nanocomposite material MnPB@PDA.

[0050] Figure 2 The morphology of MnPB@PDA observed under a transmission electron microscope is shown. MnPB@PDA has a clear core-shell structure with an average size of 245 nm, of which the average thickness of the PDA shell is 23 nm.

[0051] Figure 3 The element distribution map of MnPB@PDA shown in the figure proves that MnPB@PDA contains Fe, Mn, C, N, and O elements and is evenly distributed.

[0052] Figure 4 The absorption spectra shown confirm that both MnPB@PDA and the product MnPB of Example 1 have strong absorption capabilities for near-infrared light, and the wrapping of the PDA shell can significantly improve the absorption effect of the nanomaterial on near-infrared light.

[0053] Example 5:

[0054] The steps and process are the same as those in Example 4, except that 8 mg of MnPB prepared in Example 3 is used instead, the mass of dopamine hydrochloride is changed to 40 mg, and the corresponding concentration of dopamine hydrochloride solution is 0.026 mol / L. The morphology of the obtained nanocomposite material MnPB@PDA observed under transmission electron microscopy is the same as that in Example 4, but the average size is 134 nm, wherein the average thickness of the PDA shell is 20 nm.

[0055] Example 6:

[0056] The steps and process are the same as those in Example 4, except that 8 mg of MnPB prepared in Example 3 is used instead, the mass of dopamine hydrochloride is changed to 4 mg, and the corresponding concentration of dopamine hydrochloride solution is 0.0026 mol / L. The morphology of the obtained nanocomposite material MnPB@PDA observed under transmission electron microscopy is the same as that in Example 4, but the average size is 115 nm, wherein the average thickness of the PDA shell is 10 nm.

[0057] Example 7:

[0058] The products of Example 1 and Example 4 were prepared into dispersions with a concentration of 0.8 mg / mL, placed in centrifuge tubes and placed in a centrifuge tube at a power density of 1.2 W / cm 2 The sample was irradiated with an 808 nm near-infrared laser, and the temperature of the liquid was recorded with a digital thermometer to determine the photothermal properties of the sample. In order to determine the stability of the product of Example 4 under an 808 nm near-infrared laser, the dispersion was allowed to cool naturally to room temperature after the first irradiation, and then the light source was turned on repeatedly for 15 minutes. This irradiation-cooling process was repeated for a total of 4 cycles, and the temperature changes during the entire process were recorded.

[0059] Figure 5 The temperature changes of the product dispersions of Example 1 and Example 4 within 15 minutes of near-infrared laser irradiation are shown. Their temperature increases are 23.5°C and 24.7°C, respectively. Under the same conditions, the temperature increase of water is only 5.8°C, which proves that both MnPB and MnPB@PDA have photothermal conversion properties, and the PDA layer wrapping can enhance the photothermal performance of the nanoparticles.

[0060] Figure 6 The temperature rise effect of the dispersion of the product of Example 4 under 808nm near-infrared laser irradiation at different power densities is shown. The temperature rise of the dispersion increases gradually with the increase of the optical power density. When the laser power density reaches 1.2W / cm 2 and above, the temperature of the dispersion can reach or exceed 50 °C (room temperature is 25 °C at 0 min), indicating that the nanocomposite material is expected to be used for photothermal antibacterial applications.

[0061] Figure 7 The temperature rise of the dispersion of the product of Example 4 during the four illumination-cooling cycle tests is shown as follows: There is no obvious decrease, showing good photothermal stability. The data of the first cooling process in the figure are fitted and calculated. The photothermal efficiency of MnPB@PDA is 27.1%.

[0062] Based on the above results, it can be seen that nanocomposites MnPB@PDA It has good photothermal properties and stability, which are essential properties for the nanocomposite material to be used for photothermal antibacterial treatment.

[0063] Example 8:

[0064] Weigh 10 mg of the product of Example 4, add 2 mL of water to disperse it, then drop 2 mL of 10 mg / mL copper chloride solution into it. Stir and react for 12 h, then centrifuge to remove the mother liquor, and wash with water 5 times to obtain Cu 2+ Ion-adsorbed nanocomposite MnPB@PDA-Cu 2+ .

[0065] Figure 8 shown MnPB@PDA-Cu 2+ The morphology observed under a transmission electron microscope showed that the particle size and morphology were similar to those of the product MnPB@PDA in Example 4, but the surface was rougher.

[0066] Figure 9 shown MnPB@PDA-Cu 2+ Element distribution diagram, determine Cu 2+ It was successfully adsorbed on the MnPB@PDA surface and evenly distributed.

[0067] Figure 10 The MnPB@PDA-Cu 2+ Cu 2p X-ray photoelectron spectrum, the signal peak position confirms that the nanomaterial contains Cu 2+ ions, and the mass fraction of Cu was measured by plasma mass spectrometry to be 8.6%.

[0068] Figure 11 The MnPB@PDA-Cu 2+ and the absorption spectrum of MnPB@PDA in Example 4, MnPB@PDA-Cu 2+ The absorbance at 808 nm is greater, indicating that Cu 2+ The adsorption of enhanced the absorption of 808nm near-infrared light by the nanocomposite.

[0069] Figure 12 The MnPB@PDA-Cu 2+ The temperature change during the 808nm near-infrared laser irradiation-cooling 4 cycles reached 25.1℃ within 15min, and the corresponding dispersion temperature exceeded 50℃ and had good photothermal stability. Figure 12 The data of the first cooling process were fitted to calculate the MnPB@PDA-Cu 2+ The photothermal efficiency is 31.2%, which is higher than the photothermal efficiency of the product MnPB@PDA in Example 4.

[0070] Based on the above data, MnPB@PDA-Cu 2+ The photothermal performance is better than that of MnPB@PDA and MnPB@PDA-Cu 2+ It has better prospects for photothermal applications.

[0071] Example 9:

[0072] The steps and process are the same as those in Example 8, except that a 10 mg / mL zinc sulfate heptahydrate solution is used to obtain Zn 2+ Combined nanocomposite MnPB@PDA-Zn 2+ The morphology observed under a transmission electron microscope was similar to that of Example 8, and the mass fraction of Zn was measured by an inductively coupled plasma mass spectrometer to be 4.7%.

[0073] Example 10:

[0074] The dark toxicity and photothermal antibacterial properties of MnPB@PDA were tested by plate method. The specific operation process was as follows: the product of Example 4 was added to 1 mL of Escherichia coli suspension to make the particle concentration in the suspension 0.8 mg / mL and the bacterial solution concentration 1×10 6 CFU / mL, the mixture was shaken and cultured in the dark for 30 min, 50 μL was aspirated and diluted 100 times with LB medium, and then evenly spread on the surface of agar solid medium and placed in a CO2 incubator (37 ° C). The remaining bacterial suspension was placed in a power density of 1.2 W / cm 2 The cells were irradiated with an 808nm near-infrared laser for 5min, 10min and 15min. The mixed bacterial solution obtained at each time point was diluted and spread on the surface of the solid culture medium using the same method and then placed in a CO2 incubator. All solid culture media were cultured in the dark at 37±5℃ for 24h, then taken out and the colony distribution was observed. The bacterial suspension with an equal volume of liquid culture medium was used as the blank group.

[0075] Figure 13 The data show the antibacterial effect of MnPB@PDA on Escherichia coli under different illumination times in darkness and 808nm near-infrared light. Compared with the blank group, MnPB@PDA did not show obvious inhibitory effect on the reproduction of Escherichia coli in a dark environment, indicating that the dark toxicity of the nanocomposite material is very low. With the extension of illumination time, the number of colony distribution in the blank group did not decrease significantly, while the number of colony distribution in the experimental group decreased rapidly. Escherichia coli was completely killed after 15 minutes of illumination, proving that MnPB@PDA has photothermal antibacterial properties.

[0076] Example 11:

[0077] The antibacterial properties of nanoparticles with different compositions were compared by plate method. The specific operation process was as follows: the products of Example 1, Example 4 and Example 8 were added to a group of 1 mL of Escherichia coli bacterial suspension, respectively, so that the concentration of nanoparticles in the bacterial suspension was 0.8 mg / mL and the bacterial suspension concentration was 1×10 6 CFU / mL, a bacterial suspension to which an equal volume of CuCl2 solution (concentration of 68.8 μg / mL, the same as the Cu content in the product group of Example 8) was added was used as a control group, and a bacterial suspension to which an equal volume of liquid culture medium was added was used as a blank group. The method described in Example 10 was used to test dark culture and the use of a power density of 1.2 W / cm 2 Bacterial growth of a bacterial suspension irradiated with 808 nm near-infrared laser for 5 min and cultured on a solid culture medium at 37 ± 5 °C for 24 h.

[0078] Figure 14 The experimental groups shown are MnPB, MnPB@PDA, and MnPB@PDA-Cu 2+, the antibacterial properties of the control group CuCl2 and the blank group. Under dark conditions, except for the control group CuCl2 showing certain antibacterial properties, the three nanomaterials had no obvious toxicity to Escherichia coli. Under light, MnPB@PDA-Cu 2+ The antibacterial activity exhibited was significantly better than that of MnPB@PDA, MnPB and the control group CuCl2. It was the only sample that completely killed bacteria within 5 minutes, demonstrating the synergistic bactericidal effect of photothermal effect and copper ions, and had the best antibacterial performance.

[0079] Example 12:

[0080] The MnPB@PDA-Cu was tested by plate method. 2+ The specific operation process is as follows: different masses of the product of Example 8 are added to a group of 1 mL of Escherichia coli bacterial suspensions, so that the concentrations of the nanoparticles in the bacterial suspension are 0.8, 0.4, 0.2, 0.1, 0.05, 0.025, 0.0125 and 0.00625 mg / mL, respectively. The method described in Example 10 is used for the test, and the power density is 1.2 W / cm 2 The bacterial growth condition of the mixed solution after irradiation with 808nm near-infrared laser for 5 minutes and cultured on the surface of solid culture medium at 37±5℃ for 24 hours was measured. The minimum antibacterial concentration at which no bacteria grew was the minimum inhibitory concentration of the sample.

[0081] Figure 15 Different concentrations of MnPB@PDA-Cu 2+ The antibacterial performance of the nanoparticles under near-infrared light is that they cannot completely kill bacteria when the concentration is less than 0.2 mg / mL. 2+ The minimum inhibitory concentration of MnPB@PDA-Cu 2+ The concentration and light exposure time required to achieve complete sterilization are significantly less than Figure 13 Example 4 MnPB@PDA is shown, therefore, MnPB@PDA-Cu 2+ As an antimicrobial agent, it can achieve faster and more efficient antimicrobial applications.

[0082] Example 13:

[0083] The hydroxyl radical scavenging ability of MnPB and MnPB@PDA was tested using terephthalic acid: the products of Example 1 and Example 4 were added to acetate buffer (10 mmol / L, pH 5.5) containing terephthalic acid (0.5 mmol / L), ferrous sulfate (0.1 mmol / L), and H2O2 (10 mmol / L), respectively. After mixing and shaking for 5 minutes, the fluorescence intensity of the mixture was measured at 425 nm (excitation wavelength 315 nm). The scavenging rate was calculated according to the following formula:

[0084] Clearance rate = [1-(sample group intensity-background intensity) / (blank group intensity-background intensity)]*100%.

[0085] Figure 16 Both nanoparticles shown have the ability to scavenge hydroxyl radicals. The PDA shell coating of MnPB can enhance the scavenging rate of hydroxyl radicals, and as the particle concentration increases, the ability of MnPB@PDA to scavenge hydroxyl radicals increases accordingly.

[0086] Example 14:

[0087] The superoxide radical scavenging ability of MnPB and MnPB@PDA was measured using the nitroblue tetrazolium method: The products of Example 1 and Example 4 were added to 2 mL of phosphate buffer (10 mmol / L, pH 7.4) containing nitroblue tetrazolium (75 μmol / L), riboflavin (20 μmol / L), and methionine (12.5 mmol / L). The mixture was irradiated under a xenon lamp (emitting visible light) for 20 minutes, and the absorbance of the mixed solution at 560 nm was measured. The illuminated reaction system without the addition of nanoparticles served as the positive control group, and the reaction system without the addition of nanoparticles and without illumination served as the negative control group. The superoxide radical scavenging ability of the nanoparticles was calculated according to the following formula:

[0088] Clearance rate = [1-(positive control group value-experimental group value) / (positive control group value-negative control group value)]*100%.

[0089] Figure 17 The results show that the ability of MnPB@PDA to scavenge superoxide radicals is stronger than that of MnPB, and as the particle concentration increases, the ability of MnPB@PDA to scavenge superoxide radicals gradually increases.

[0090] Example 15:

[0091] The therapeutic effect of MnPB@PDA on skin wound healing was determined by means of a rat animal model. The specific method is as follows: a rat with a 10 mm diameter circular full-thickness skin cut off from the back was used as an animal model, and the rats were randomly divided into 4 groups, with 5 rats in each group. The prepared and sterilized dispersion of the product of Example 1 (2 mg / mL), the high-concentration dispersion of the product of Example 4 (2 mg / mL) and the low-concentration dispersion group (0.5 mg / mL) were used as experimental group samples, and normal saline was used as the control group sample. Each group of samples was added dropwise to sterile gauze, which was adhered to the wound surface by wet compressing, covered with a waterproof and breathable membrane and fixed on the rat (recorded as day 1). The dressings were changed on the 4th, 7th, 10th and 13th days respectively, and the experiment was terminated on the 15th day. Based on the wound healing condition and the size of the wound diameter of each group of animals, the feasibility of the samples for skin wound healing was evaluated.

[0092] The results confirmed that both MnPB and MnPB@PDA have the effect of promoting wound healing. The skin of rats treated with high-concentration MnPB@PDA was completely healed on the 10th day, while the average wound sizes of the high-concentration MnPB, low-concentration MnPB@PDA and normal saline groups were 0.10cm, 0.15cm and 0.30cm on the 15th day, respectively. This shows that the healing effect of MnPB@PDA on skin wounds is correlated with the dosage, and the therapeutic effect is better than MnPB at the same concentration. No animal death, disability or wound tissue necrosis occurred during the experiment, confirming that MnPB@PDA can be used as an agent to promote wound healing.

Claims

1. A nanocomposite material MnPB@PDA containing Prussian blue nanocubes doped with manganese ions, characterized in that :The nanocomposite material MnPB@PDA is composed of manganese ion-doped Prussian blue nanocubes MnPB as the core and polydopamine PDA wrapped around the periphery.

2. The nanocomposite material according to claim 1, wherein: Its surface can further adsorb copper ions Cu 2 + or zinc ion Zn 2+ .

3. The nanocomposite material according to claim 2, characterized in that: The copper ion Cu 2+ or zinc ion Zn 2+ It can be derived from any one of copper acetate, copper sulfate, copper chloride, zinc acetate, zinc sulfate, and zinc chloride.

4. The nanocomposite material according to claim 1, wherein: The average particle size of the nanocomposite is 115-245 nm, of which the average size of the MnPB core is 95-200 nm and the average thickness of the PDA shell is 10-23 nm.

5. The nanocomposite material according to any one of claims 1 to 4, characterized in that: It can be used for photothermal antibacterial, active oxygen scavenging and wound healing treatment at the same time.

6. The method for preparing the nanocomposite material according to claim 1, wherein: Follow these steps: Step 1. Preparation of manganese ion-doped Prussian blue nanocubes (MnPB): Dissolve a certain amount of manganese acetate tetrahydrate and ferrous sulfate heptahydrate in 20 mL of 0.01 mol / L hydrochloric acid to obtain solution A. Dissolve 1.0 g of polyvinyl pyrrolidone and a certain amount of potassium hexacyanoferrate (III) in 20 mL of water to obtain solution B. Add solution A dropwise to solution B with stirring. Stirring is then turned off and the temperature is raised to 90°C for 5 hours. The mother liquor is removed by centrifugation. The product is washed five times with ethanol and then water, respectively, and then dried in vacuo at 40°C to obtain MnPB.

7. Step 2. PDA Shell Coating of MnPB: Add 8 mg of the MnPB prepared in Step 1 and 8 mL of water to a reaction flask. Once the mixture is thoroughly mixed, add 8 mL of Tris-HCl buffer (0.01 mol / L, pH 7.9) containing dopamine hydrochloride dropwise to the reaction flask. Stir the reaction at room temperature for 12 hours to complete the PDA shell coating of the MnPB. The mixture is centrifuged to remove the supernatant, washed five times with water, and then dried under vacuum at 40°C to obtain the MnPB@PDA nanocomposite.

8. The method for preparing the nanocomposite material according to claim 6, wherein: In step 1, the concentrations of manganese acetate and ferrous sulfate contained in solution A are 0.05 mol / L to 0.5 mol / L, and the concentration of potassium hexacyanoferrate (III) contained in solution B is 0.1 mol / L to 1.0 mol / L.

9. The method for preparing the nanocomposite material according to claim 6, wherein: The concentration of dopamine hydrochloride in the Tris-HCl buffer in step 2 is 0.0026 mol / L to 0.053 mol / L.

10. The method for preparing the nanocomposite material according to claim 6, wherein: In step 2, the mass ratio of MnPB to dopamine hydrochloride is 1:0.5~1:20.

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