Injectable antibacterial anti-inflammatory high internal phase emulsions, methods of making and using the same

Abstract

The present application relates to a kind of injectable antibacterial anti-inflammatory high internal phase emulsion promoting periodontal tissue regeneration and preparation method thereof.The preparation method of the emulsion includes the following steps: (1) preparation is made of distilled water, growth factor protein nanoparticle and trace element doped hydroxyapatite nanoparticle consisting of continuous phase;(2) in continuous phase, add the dispersed phase containing natural flavonoids and pharmaceutical oil, obtain high internal phase Pickering emulsion after emulsification.The high internal phase emulsion constructed by the present application is an integrated repair system for periodontal disease treatment, can be according to different particle concentration to control the release of trace element and natural flavonoids, with higher antibacterial, anti-inflammatory activity, bone tissue repair capacity and injectability, can be applied to drug controlled release system, periodontal disease treatment and other biomedical fields.

Description

Technical Field

[0001] This invention belongs to the field of pharmaceutical science, specifically an injectable antibacterial and anti-inflammatory high internal phase emulsion, its preparation method, and its application. Background Technology

[0002] Periodontitis is a chronic infectious disease caused by microbial imbalance, characterized by the destruction of connective tissue attachment, alveolar bone loss, and tooth loss. Bacteria are the main pathogenic factor, negatively impacting not only chewing function, aesthetics, and quality of life, but also imposing a significant social and economic burden. The focus of periodontitis treatment is on effectively removing bacterial accumulations around the tooth roots, controlling inflammation, and promoting periodontal and alveolar bone regeneration. Current clinical treatment strategies primarily rely on mechanical therapies such as ultrasonic scalers and periodontal curettage, along with the use of antibiotics, to reduce the bacterial load on the periodontium. However, due to the irregular anatomical structure of periodontal pockets, periodontitis presents certain challenges and difficulties in treatment, including long treatment cycles, difficulty in radical cure, and poor repair of alveolar bone and gingival damage.

[0003] High internal phase Pickering emulsions, typically referring to emulsions stabilized by solid particles with a dispersed phase volume fraction exceeding 74%, are also known as gel emulsions. Due to their extremely high internal phase ratio, they can load a large amount of lipid-soluble substances, and the thick, dense solid particle adsorption layer at the emulsion interface can block pro-oxidants, thereby improving the stability of the active loading. Therefore, high internal phase Pickering emulsions are an excellent delivery carrier for encapsulating bioactive compounds, improving their stability, and achieving controlled release. Furthermore, because high internal phase Pickering emulsions have a low water content, they are less prone to deterioration and exhibit better stability compared to ordinary emulsions. Therefore, high internal phase emulsions are currently used in the food, pharmaceutical, and cosmetic industries.

[0004] Natural compounds are the best choice for treating various diseases. Among them, flavonoids stand out due to their wide distribution in fruits, vegetables, grains, herbs, and beverages. In recent years, flavonoids have attracted attention, and in vitro and in vivo studies have shown that flavonoids have many benefits, such as antibacterial, anti-inflammatory, antioxidant, neuroprotective, and potent anticancer effects, which can meet the antibacterial and anti-inflammatory needs in the treatment of periodontitis. However, the poor water solubility of flavonoids leads to low bioavailability, and most flavonoid compounds are unstable under high temperature and light conditions, limiting their application in disease treatment.

[0005] Hydroxyapatite is a major inorganic component of human bone, exhibiting excellent biocompatibility and promoting angiogenesis and the repair of damaged tissues, particularly bone repair. Its composite materials have been widely used in tissue and bone regeneration. Besides hydroxyapatite, human bone also contains trace elements such as silicon, magnesium, zinc, iron, strontium, and carbonate. The Ca ions in hydroxyapatite are easily replaced by these metal ions, making its structure more biomimetic to human bone and thus enhancing its bioactivity.

[0006] Growth factors are a group of polypeptide molecules that regulate cell growth and metabolism. They have multiple regulatory functions and can stimulate the body's tissue self-repair and regeneration potential to a certain extent, thus achieving periodontal tissue regeneration. Currently, many growth factors are considered to play a key role in the periodontal tissue repair and regeneration process, such as bone morphogenetic protein (BMP), basic fibroblast growth factor (bFGF), platelet-derived growth factor (PDGF), insulin-like growth factor (IGF), and concentrated growth factor (CGF).

[0007] Therefore, to treat periodontitis, an injectable antibacterial and anti-inflammatory high-internal-phase emulsion that promotes periodontal tissue regeneration can be prepared using a high-internal-phase Pickering emulsion as a template. This emulsion can improve the bioavailability and stability of flavonoids to meet the antibacterial and anti-inflammatory requirements during periodontitis treatment. It can also load growth factors and trace functional elements onto hydroxyapatite nanoparticles to achieve controlled release of growth factors and trace functional elements and alveolar bone repair during periodontitis treatment. Summary of the Invention

[0008] This invention aims to overcome the problems of poor stability and low bioavailability of natural flavonoids by using a high internal phase emulsion as a carrier to enhance drug loading. It employs trace amounts of functional element-doped hydroxyapatite nanoparticles and growth factor-loaded protein nanoparticles as emulsion stabilizers, enabling the high internal phase emulsion to integrate multiple functions such as good injectability, antibacterial properties, biocompatibility, angiogenesis promotion, and bone tissue repair. This provides a comprehensive treatment and repair system for periodontal diseases, offering antibacterial, anti-inflammatory, antioxidant, injectable, angiogenesis-promoting, and bone tissue repair capabilities.

[0009] This invention provides an injectable antibacterial and anti-inflammatory high-internal-phase emulsion for promoting periodontal tissue regeneration, prepared using a high-internal-phase Pickering emulsion as a template. Growth factor protein nanoparticles and trace functional element-doped hydroxyapatite nanoparticles are added as stabilizers to a continuous phase, which is then mixed and homogenized with a dispersed phase containing natural flavonoids and pharmaceutical oils to obtain the injectable antibacterial and anti-inflammatory high-internal-phase emulsion. Gelatin and natural flavonoids are widely available and inexpensive raw materials. The high-internal-phase Pickering emulsion template exhibits high stability and, as a controlled-release system, can increase the bioavailability and loading rate of natural flavonoids, improve their stability, and achieve the slow release of growth factors, natural flavonoids, and trace functional element-doped hydroxyapatite nanoparticles.

[0010] To achieve the above objectives, the present invention adopts the following technical solution:

[0011] (1) Dissolve type B gelatin thoroughly in phosphate buffer (0.1 mol / L), add ethylenediamine and adjust the pH of the solution to 5.0, add EDC and bring the volume to 250 mL with phosphate buffer (0.1 mol / L), react for 1 hour, dialyze and freeze dry to obtain aminated gelatin. Dissolve aminated gelatin thoroughly in distilled water, add acetone to obtain a precipitate, redissolve the precipitate in distilled water and adjust the pH of the solution to 4.0, add acetone again until a precipitate is formed, then add crosslinking agent (genipin is used at 5-10% of the gelatin mass) to the solution and continue the reaction at 40℃ for 3-5 hours. Centrifuge the solution after reaction at 10000 rpm for 20-30 minutes to obtain aminated gelatin nanoparticles;

[0012] (2) Prepare a Ca(OH)2 solution and add a compound containing a functional element to replace part of the Ca in the system with the functional element. Stir in a closed container at room temperature for 2-3 hours until a uniform suspension is formed (0.25-0.1 mL of polyethylene glycol-400 is added during this period). Prepare an H3PO4 solution (0.2-0.5 M) and add it dropwise to the above suspension. Stir at room temperature for 4 hours and then stop stirring. Let it age for 24 hours. Take the lower layer of suspension and wash it twice by repeated centrifugation with anhydrous ethanol and RO water. Then dry, grind and calcine it to obtain trace functional element-doped hydroxyapatite nanoparticles.

[0013] (3) A continuous phase consisting of distilled water, growth factor protein nanoparticles and trace functional element-doped hydroxyapatite nanoparticles is mixed with a dispersed phase containing natural flavonoids and pharmaceutical oil at a volume ratio of 1:3 to 1:4 under the condition of 13000 to 15000 rpm to form an O / W type high internal phase Pickering emulsion.

[0014] (4) Stored at 4℃ in the dark to obtain an injectable antibacterial and anti-inflammatory high internal phase emulsion for promoting periodontal tissue regeneration, prepared by the Pickering emulsion method. In this invention, the growth factor loaded on the protein nanoparticles can be any one of IGF-1, VEGF, PDGF, BMP, and CGF; the trace functional element compound used to prepare trace functional element-doped hydroxyapatite nanoparticles can be any one of inorganic compounds containing Cu, Mg, Zn, Co, Mn, Se, and Sr; the natural flavonoid compound can be any one of quercetin, apigenin, luteolin, morin, myricetin, hesperidin, and catechin; and the medicinal oil can be any one of isopropyl myristate, corn oil, sunflower seed oil, MCT oil, and soybean oil.

[0015] This invention prepares protein nanoparticles using natural polymer gelatin as raw material, loads growth factors onto the protein nanoparticles, and uses a very small amount of growth factor-loaded protein nanoparticles and trace amounts of functional element-doped hydroxyapatite nanoparticles as emulsifiers to prepare a high internal phase Pickering emulsion with excellent stability.

[0016] The high internal phase Pickering emulsion provided by this invention has a dispersed phase volume fraction of 75-80%, which can support a large amount of natural flavonoids. The protein nanoparticle and trace functional element-doped hydroxyapatite nanoparticle adsorption layer on the emulsion template interface can effectively improve the stability of natural flavonoids and achieve the slow release of growth factors, trace functional element-doped hydroxyapatite nanoparticles, and natural flavonoids. The released natural flavonoids, growth factors, and trace functional element-doped hydroxyapatite nanoparticles work together to exert anti-inflammatory, antibacterial, antioxidant, angiogenesis-promoting, and bone tissue repair effects.

[0017] Therefore, the high internal phase emulsion stabilized by protein nanoparticles and trace element-doped hydroxyapatite nanoparticles provided by this invention has anti-inflammatory, antioxidant, antibacterial, angiogenesis-promoting, and bone tissue repair capabilities, and has great application prospects in biomedical fields such as drug controlled release systems and periodontitis treatment.

[0018] Therefore, the injectable antibacterial and anti-inflammatory high internal phase emulsion prepared using the present invention has the following advantages:

[0019] (1) The protein nanoparticles prepared in this invention are aminated gelatin nanoparticles with good wettability, biocompatibility and stability, and the formation of high internal phase Pickering emulsion only requires a small amount (0.1 wt%) of protein nanoparticles.

[0020] (2) The trace functional element-doped hydroxyapatite nanoparticles prepared by the present invention can achieve slow release of trace functional elements and hydroxyapatite nanoparticles, and have good biocompatibility, angiogenesis and bone tissue repair capabilities, and can be used for tissue repair and bone regeneration.

[0021] (3) The natural flavonoids used in this invention have been shown to have many benefits, such as antibacterial, anti-inflammatory, antioxidant, neuroprotective and powerful anticancer effects, and are widely available and inexpensive.

[0022] (4) The present invention uses protein nanoparticles to load growth factors, which can stimulate the potential of the body's tissues to self-repair and regenerate to a certain extent, thereby achieving periodontal tissue regeneration and slow release of growth factors.

[0023] (5) The protein nanoparticles and trace functional element-doped hydroxyapatite nanoparticles prepared in this invention have a large internal phase volume fraction in the high internal phase Pickering emulsion, which can load a large amount of natural flavonoids and improve the bioavailability of flavonoids. This is of great significance for improving the resource utilization of natural products.

[0024] (6) The high internal phase Pickering emulsion stabilized by the protein nanoparticles and trace functional element-doped hydroxyapatite nanoparticles prepared in this invention has good storage stability and can effectively improve the stability of flavonoids.

[0025] (7) The injectable antibacterial and anti-inflammatory high internal phase emulsion prepared by the present invention provides an integrated repair system for the treatment of periodontal diseases with antibacterial, anti-inflammatory, antioxidant, injectable, angiogenesis-promoting and bone tissue repair capabilities. Attached Figure Description

[0026] Figure 1 The injectable antibacterial and anti-inflammatory high internal phase emulsion prepared in Example 1;

[0027] Figure 2 Laser confocal microscopy image of the injectable antibacterial and anti-inflammatory high internal phase emulsion prepared in Example 1;

[0028] Figure 3 Micro-CT image of periodontitis treatment using the injectable antibacterial and anti-inflammatory high internal phase emulsion prepared in Example 1. Detailed Implementation

[0029] The present invention will be further described below with reference to specific embodiments. The advantages and features of the present invention will become clearer as the embodiments are described. However, the embodiments are merely exemplary and do not constitute any limitation on the scope of the present invention.

[0030] Example 1

[0031] Dissolve 5.0 g of type B gelatin in 125 mL of phosphate buffer (0.1 mol / L) until fully dissolved. Add 16 mL of ethylenediamine to adjust the pH of the solution to 5.0, then add 3.055 g of EDC and bring the volume to 250 mL with phosphate buffer. React for 1 hour, dialyze, and freeze dry to obtain aminated gelatin.

[0032] Dissolve 1.25g of aminated gelatin in 25mL of distilled water and keep it at 40℃ until fully dissolved. Add 25mL of acetone and continue to add 15mL of distilled water until the solution is clear and adjust the pH to 4.0. Add acetone again until a white precipitate is formed. Then add 200μL of genipin solution to the solution and continue to react at 40℃ for 3 hours. Centrifuge the reacted solution at 10000rpm for 30 minutes to obtain aminated gelatin nanoparticles.

[0033] Take 5 mL of aminated gelatin nanoparticles, and mix 25 μg of IGF-1 with the aminated gelatin nanoparticles at 4 °C for 15 hours to obtain protein nanoparticles loaded with IGF-1.

[0034] Dissolve 0.398 g of anhydrous copper sulfate in 200 mL of RO water. Add 3.52 g of Ca(OH)2 to the above solution. Stir the mixture in a sealed container at room temperature for 2 hours until a uniform suspension is formed (add 0.1 mL of polyethylene glycol during this period). Add 100 mL of 0.3 M H3PO4 solution dropwise to the suspension. Stir at room temperature for 4 hours and then stop stirring. After aging for 24 hours, take the lower layer of suspension and wash it twice by repeated centrifugation with anhydrous ethanol and RO water. Dry, grind, and calcine the suspension to obtain copper-doped hydroxyapatite nanoparticles.

[0035] Prepare a 1 mL continuous phase aqueous solution, wherein the concentration of protein nanoparticles is 10 mg / mL and the concentration of copper-doped hydroxyapatite nanoparticles is 5 mg / mL; prepare a 3 mL dispersed phase, wherein 2.25 mg of quercetin is dissolved in 3 mL of LMCT oil; stir the two phases at 13000 rpm for 30 s and store at 4 °C in the dark to obtain an injectable antibacterial and anti-inflammatory high internal phase emulsion that promotes periodontal tissue regeneration.

[0036] Example 2

[0037] Dissolve 5.0 g of type B gelatin in 125 mL of phosphate buffer (0.1 mol / L) until fully dissolved. Add 16 mL of ethylenediamine to adjust the pH of the solution to 5.0, then add 3.055 g of EDC and bring the volume to 250 mL with phosphate buffer. React for 1 hour, dialyze, and freeze dry to obtain aminated gelatin.

[0038] Dissolve 1.25g of aminated gelatin in 25mL of distilled water and keep it at 40℃ until fully dissolved. Add 25mL of acetone and continue to add 15mL of distilled water until the solution is clear and adjust the pH to 4.0. Add acetone again until a white precipitate is formed. Then add 200μL of genipin solution to the solution and continue to react at 40℃ for 3 hours. Centrifuge the reacted solution at 10000rpm for 30 minutes to obtain aminated gelatin nanoparticles.

[0039] Take 5 mL of aminated gelatin nanoparticles, and mix 25 μg of IGF-1 with the aminated gelatin nanoparticles at 4 °C for 15 hours to obtain protein nanoparticles loaded with IGF-1.

[0040] Dissolve 0.744 g of zinc nitrate in 200 mL of RO water. Add 3.52 g of Ca(OH)2 to the above solution. Stir the mixture in a sealed container at room temperature for 2 hours until a uniform suspension is formed (add 0.1 mL of polyethylene glycol during this period). Add 100 mL of H3PO4 solution (0.3 M) dropwise to the suspension. Stir at room temperature for 4 hours and then stop stirring. After aging for 24 hours, take the lower layer of suspension and wash it twice by repeated centrifugation with anhydrous ethanol and RO water. Dry, grind, and calcine the suspension to obtain zinc-doped hydroxyapatite nanoparticles.

[0041] Prepare a 1 mL continuous phase aqueous solution, wherein the concentration of protein nanoparticles is 5 mg / mL and the concentration of zinc-doped hydroxyapatite nanoparticles is 5 mg / mL; prepare a 3 mL dispersed phase, wherein 2.25 mg of catechin is dissolved in 3 mL of LMCT oil; stir the two phases at 13000 rpm for 30 s and store at 4 °C in the dark to obtain an injectable antibacterial and anti-inflammatory high internal phase emulsion that promotes periodontal tissue regeneration.

[0042] Example 3

[0043] Dissolve 5.0 g of type B gelatin in 125 mL of phosphate buffer (0.1 mol / L) until fully dissolved. Add 16 mL of ethylenediamine to adjust the pH of the solution to 5.0, then add 3.055 g of EDC and bring the volume to 250 mL with phosphate buffer. React for 1 hour, dialyze, and freeze dry to obtain aminated gelatin.

[0044] Dissolve 1.25g of aminated gelatin in 25mL of distilled water and keep it at 40℃ until fully dissolved. Add 25mL of acetone and continue to add 15mL of distilled water until the solution is clear and adjust the pH to 4.0. Add acetone again until a white precipitate is formed. Then add 200μL of genipin solution to the solution and continue to react at 40℃ for 3 hours. Centrifuge the reacted solution at 10000rpm for 30 minutes to obtain aminated gelatin nanoparticles.

[0045] Take 5 mL of aminated gelatin nanoparticles, mix 12.5 μg of VEGF with the aminated gelatin nanoparticles at 4 °C and stir for 15 hours to obtain VEGF-loaded protein nanoparticles.

[0046] Dissolve 0.398 g of anhydrous copper sulfate in 200 mL of RO water. Add 3.52 g of Ca(OH)2 to the above solution. Stir the mixture in a sealed container at room temperature for 3 hours until a uniform suspension is formed (add 0.1 mL of polyethylene glycol during this period). Add 100 mL of H3PO4 solution (0.3 M) dropwise to the suspension. Stir at room temperature for 4 hours and then stop stirring. After aging for 24 hours, take the lower layer of suspension and wash it twice by repeated centrifugation with anhydrous ethanol and RO water. Dry, grind, and calcine the suspension to obtain copper-doped hydroxyapatite nanoparticles.

[0047] Prepare a 0.8 mL continuous phase aqueous solution, wherein the concentration of protein nanoparticles is 5 mg / mL and the concentration of copper-doped hydroxyapatite nanoparticles is 6 mg / mL; prepare a 3.2 mL dispersed phase, wherein 3.2 mg of morin is dissolved in 3.2 mL of corn oil; stir the two phases at 15000 rpm for 30 s and store at 4 °C in the dark to obtain an injectable antibacterial and anti-inflammatory high internal phase emulsion that promotes periodontal tissue regeneration.

[0048] Example 4

[0049] Dissolve 5.0 g of type B gelatin in 125 mL of phosphate buffer (0.1 mol / L) until fully dissolved. Add 16 mL of ethylenediamine to adjust the pH of the solution to 5.0, then add 3.055 g of EDC and bring the volume to 250 mL with phosphate buffer. React for 1 hour, dialyze, and freeze dry to obtain aminated gelatin.

[0050] Dissolve 1.25g of aminated gelatin in 25mL of distilled water and keep it at 40℃ until fully dissolved. Add 25mL of acetone and continue to add 15mL of distilled water until the solution is clear and adjust the pH to 4.0. Add acetone again until a white precipitate is formed. Then add 200μL of genipin solution to the solution and continue to react at 40℃ for 3 hours. Centrifuge the reacted solution at 10000rpm for 30 minutes to obtain aminated gelatin nanoparticles.

[0051] Take 5 mL of aminated gelatin nanoparticles, mix 12.5 μg of VEGF with the aminated gelatin nanoparticles at 4 °C and stir for 15 hours to obtain VEGF-loaded protein nanoparticles.

[0052] Dissolve 0.398 g of anhydrous copper sulfate in 200 mL of RO water. Add 3.52 g of Ca(OH)2 to the above solution. Stir the mixture in a sealed container at room temperature for 3 hours until a uniform suspension is formed (add 0.1 mL of polyethylene glycol during this period). Add 100 mL of H3PO4 solution (0.3 M) dropwise to the suspension. Stir at room temperature for 4 hours and then stop stirring. After aging for 24 hours, take the lower layer of suspension and wash it twice by repeated centrifugation with anhydrous ethanol and RO water. Dry, grind, and calcine the suspension to obtain copper-doped hydroxyapatite nanoparticles.

[0053] Prepare a 0.8 mL continuous phase aqueous solution, wherein the concentration of protein nanoparticles is 10 mg / mL and the concentration of copper-doped hydroxyapatite nanoparticles is 6 mg / mL; prepare a 3.2 mL dispersed phase, wherein 3.2 mg of quercetin is dissolved in 3.2 mL of soybean oil; stir the two phases at 15000 rpm for 30 s and store at 4 °C in the dark to obtain an injectable antibacterial and anti-inflammatory high internal phase emulsion that promotes periodontal tissue regeneration.

[0054] Example 5

[0055] Dissolve 5.0 g of type B gelatin in 125 mL of phosphate buffer (0.1 mol / L) until fully dissolved. Add 16 mL of ethylenediamine to adjust the pH of the solution to 5.0, then add 3.055 g of EDC and bring the volume to 250 mL with phosphate buffer. React for 1 hour, dialyze, and freeze dry to obtain aminated gelatin.

[0056] Dissolve 1.25g of aminated gelatin in 25mL of distilled water and keep it at 40℃ until fully dissolved. Add 25mL of acetone and continue to add 15mL of distilled water until the solution is clear and adjust the pH to 4.0. Add acetone again until a white precipitate is formed. Then add 200μL of genipin solution to the solution and continue to react at 40℃ for 3 hours. Centrifuge the reacted solution at 10000rpm for 30 minutes to obtain aminated gelatin nanoparticles.

[0057] Take 5 mL of aminated gelatin nanoparticles, and mix 25 μg of IGF-1 with the aminated gelatin nanoparticles at 4 °C for 15 hours to obtain protein nanoparticles loaded with IGF-1.

[0058] Dissolve 0.744 g of zinc nitrate in 200 mL of RO water. Add 3.52 g of Ca(OH)2 to the above solution. Stir the mixture in a sealed container at room temperature for 2 hours until a uniform suspension is formed (add 0.1 mL of polyethylene glycol during this period). Add 100 mL of H3PO4 solution (0.3 M) dropwise to the suspension. Stir at room temperature for 4 hours and then stop stirring. After aging for 24 hours, take the lower layer of suspension and wash it twice by repeated centrifugation with anhydrous ethanol and RO water. Dry, grind, and calcine the suspension to obtain zinc-doped hydroxyapatite nanoparticles.

[0059] Prepare a 0.88 mL continuous phase aqueous solution, wherein the concentration of protein nanoparticles is 10 mg / mL and the concentration of zinc-doped hydroxyapatite nanoparticles is 10 mg / mL; prepare a 3.12 mL dispersed phase, wherein 2.34 mg apigenin is dissolved in 3.12 mL soybean oil; stir the two phases at 15000 rpm for 30 s and store at 4℃ in the dark to obtain an injectable antibacterial and anti-inflammatory high internal phase emulsion that promotes periodontal tissue regeneration.

Claims

1. A method for preparing an injectable antibacterial and anti-inflammatory high internal phase emulsion, characterized in that, Includes the following steps: (1) Prepare a continuous phase consisting of distilled water, protein nanoparticles and trace functional element-doped hydroxyapatite nanoparticles, wherein the concentration ranges of protein nanoparticles and trace functional element-doped hydroxyapatite nanoparticles are 4 ~ 10 mg / mL and 5 ~ 10 mg / mL, respectively. The protein nanoparticles and trace functional element-doped hydroxyapatite are used as common stabilizers for the high internal phase emulsion, with a ratio of 1:1 to 1:2.

5. The protein nanoparticles are aminated gelatin nanoparticles, and their preparation method is as follows: Type B gelatin was fully dissolved in 0.1 mol / L phosphate buffer, ethylenediamine was added and the pH of the solution was adjusted to 5.0, EDC was added and the volume was brought up to 250 mL with 0.1 mol / L phosphate buffer. After reacting for 1 hour, the solution was dialyzed and lyophilized to obtain aminated gelatin. Aminated gelatin was fully dissolved in distilled water, acetone was added to obtain a precipitate, the precipitate was redissolved in distilled water and the pH of the solution was adjusted to 4.0, acetone was added dropwise again until a precipitate was formed, and then the solution was kept at a constant temperature of 40 °C for 3-5 hours. The solution after reaction was centrifuged at 10000 rpm for 20-30 minutes to obtain aminated gelatin nanoparticles. The crosslinking agent is genipin, and its dosage is 5-10% of the gelatin mass. The aforementioned trace functional element-doped hydroxyapatite nanoparticles were prepared using a precipitation method: Prepare a Ca(OH)2 solution and add a compound containing a functional element to replace part of the Ca in the system. Stir the mixture in a closed container at room temperature for 2-3 hours until a uniform suspension is formed. During this process, add 0.25-0.1 mL of polyethylene glycol-400. Prepare a 0.2-0.5 M H3PO4 solution and add it dropwise to the suspension. Stir at room temperature for 4 hours and then stop stirring. Let it age for 24 hours. Take the lower layer of suspension and wash it twice by repeated centrifugation with anhydrous ethanol and RO water. Then dry, grind, and calcine it to obtain trace amounts of functional element-doped hydroxyapatite nanoparticles. The compounds containing the trace functional elements are any one of inorganic compounds containing Cu, Mg, Zn, Co, Mn, Se, and Sr; (2) Prepare a dispersion phase consisting of natural flavonoids and pharmaceutical oil, wherein the concentration of natural flavonoids ranges from 750 to 1000 mg / mL; The natural flavonoids mentioned are any one of quercetin, apigenin, luteolin, morin, myricetin, hesperidin, and catechin; The medicinal oil mentioned is any one of MCT oil, isopropyl myristate, corn oil, sunflower seed oil, and soybean oil; (3) The continuous phase and the dispersed phase are mixed at a volume ratio of 1:3 to 1:4 under the condition of 13000 ~ 15000 rpm to form an oil-in-water (O / W) type high internal phase Pickering emulsion.

2. The method for preparing the injectable antibacterial and anti-inflammatory high internal phase emulsion according to claim 1, characterized in that, The aminated gelatin nanoparticles are loaded with growth factors that promote periodontal tissue regeneration, and the growth factors are any one of IGF-1, VEGF, PDGF, BMP, and CGF.

3. An injectable antibacterial and anti-inflammatory high internal phase emulsion, obtained by the preparation method according to claim 1 or 2.

4. The application of the injectable antibacterial and anti-inflammatory high internal phase emulsion as described in claim 3, as a material for preparing controlled-release drugs and a material for treating periodontal diseases.

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