Antibacterial photothermal / photodynamic nanoparticles and preparation method and application thereof

Abstract

The invention discloses a method for preparing antibacterial photothermal / photodynamic nanoparticles and applications, which are carried out under light-proof conditions, and include the following steps: adding dipalmitoylphosphatidylcholine, cholesterol, distearoylphosphatidylethanolamine-polyethylene glycol, and indocyanine green to anhydrous ethanol to dissolve to obtain a liposome ethanol solution; adding the liposome ethanol solution to pure water to obtain a mixed solution; ultrasonically crushing the mixed solution to obtain liposome-encapsulated primary particles of indocyanine green; after dialysis of the primary particles of indocyanine green encapsulated by liposomes, liposome-encapsulated antibacterial photothermal / photodynamic nanoparticles of indocyanine green are obtained. The nanoparticles prepared by the present invention have good biocompatibility, effectively solve the defects of indocyanine green water solubility and poor stability, and have high application value in the field of photothermal / photodynamic synergistic anti-periodontitis Streptococcus Gordonii.

Description

Technical Field

[0001] The present invention belongs to the technical field of biomedical materials, and specifically relates to antibacterial photothermal / photodynamic nanoparticles and a preparation method and application thereof. Background Art

[0002] Periodontitis is an immune inflammatory disease caused by bacterial plaque biofilm. If not treated in time, it will lead to tooth loss, edentulous jaw, chewing dysfunction and malnutrition. Streptococcus gordonii (S. gordonii) is a Gram-positive bacterium that colonizes the tooth surface in the early stage and participates in mediating the adhesion and aggregation of other oral bacteria. At present, conventional periodontal treatment methods are prone to bacterial resistance and other problems, resulting in the inability to completely eliminate plaque microorganisms, which seriously affects the treatment effect of periodontitis.

[0003] Recently, near-infrared excited photodynamic therapy (PDT) and photothermal therapy (PTT) synergistic therapy is one of the effective strategies to combat bacterial infections. Indocyanine green (ICG) has been used in PDT and PTT as a photosensitizer and photothermal agent. ICG can produce reactive oxygen species (ROS) under near-infrared light irradiation, and the absorbed light can also be converted into heat to induce bacterial necrosis and apoptosis. Liposomes, as a nano-lipid vesicle, can encapsulate hydrophobic ICG in the lipid bilayer. ICG NPs liposome nanoparticles were constructed by nanoprecipitation method and were heated to 1 W / cm 2 Under the irradiation of 808nm near-infrared light, the accurate and efficient combination of photothermal and photodynamic therapy is used to achieve the elimination of periodontal Streptococcus Gordonii.

[0004] In summary, traditional surgical intervention and antibiotic treatment are ineffective, often hindering periodontal tissue regeneration, causing periodontal bacterial resistance, and even leading to tooth loss and systemic diseases. Therefore, it is necessary to study a safe and efficient method to provide a therapeutic prospect for the elimination of periodontal Streptococcus Gordonii. Summary of the invention

[0005] In order to solve the above problems, the present invention provides an antibacterial photothermal / photodynamic nanoparticle and its preparation method and application. The liposome nanoparticles prepared by the present invention have uniform spherical particle size, good dispersibility, good photothermal / photodynamic performance under near-infrared light irradiation, good biocompatibility, and provide potential value for the removal of periodontal Streptococcus Gordonii.

[0006] In order to achieve the above object, the present invention provides the following technical solution: a method for preparing antibacterial photothermal / photodynamic nanoparticles, the preparation method is carried out in a light-proof environment, comprising the following steps:

[0007] 1) adding dipalmitoylphosphatidylcholine, cholesterol, distearoylphosphatidylethanolamine-polyethylene glycol, and indocyanine green into anhydrous ethanol to dissolve and obtain a liposome ethanol solution;

[0008] 2) adding the liposome ethanol solution into pure water to obtain a mixed solution;

[0009] 3) subjecting the mixed solution to ultrasonic crushing to obtain primary particles of liposome-encapsulated indocyanine green;

[0010] 4) dialyzing the primary particles of indocyanine green encapsulated by liposomes to obtain antibacterial photothermal / photodynamic nanoparticles of indocyanine green encapsulated by liposomes.

[0011] The mass ratio of dipalmitoylphosphatidylcholine, cholesterol and distearoylphosphatidylethanolamine-polyethylene glycol is (7-12): (2-6): (1-2).

[0012] The mass ratio of the liposome to indocyanine green is 10-20:1, and the liposome refers to the total amount of dipalmitoylphosphatidylcholine+cholesterol+distearoylphosphatidylethanolamine-polyethylene glycol.

[0013] In step 2), the concentration of indocyanine green in the mixed solution is 0.1-1 mg / mL.

[0014] The power of the ultrasonic crushing is 30% to 40%, and the time of the ultrasonic crushing is 5 to 10 minutes.

[0015] The distearoyl phosphatidylethanolamine-polyethylene glycol is distearoyl phosphatidylethanolamine modified with polyethylene glycol 2000.

[0016] The molecular weight cut-off of the dialysis is 8000-14000Da, and the dialysis time is 12-24h.

[0017] The antibacterial photothermal / photodynamic nanoparticles of indocyanine green encapsulated by liposomes are uniform spherical particles with a particle size of 100 to 300 nm.

[0018] The antibacterial photothermal / photodynamic nanoparticles prepared by the above preparation method.

[0019] The above-mentioned antibacterial photothermal / photodynamic nanoparticles are used in the preparation of drugs for treating and inhibiting periodontal Streptococcus Gordonii.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) Through the combined effects of photothermal and photodynamic therapy, the treatment efficiency is improved while solving the problem of bacterial resistance caused by conventional periodontal treatment.

[0022] (2) The preparation method of the antibacterial photothermal / photodynamic nanoparticles of the present invention is simple and easy, has high photothermal and photodynamic sterilization performance, and the synthesized nanoparticles have good biocompatibility. When the composition concentration is 50 μg / mL and 1 W / cm 2 Irradiation with 808nm near-infrared light of high power density for 10min has a good sterilization effect on periodontal Streptococcus Gordonii.

[0023] (3) The preparation method of the present invention is simple, the product has good uniformity, is very conducive to expanding production, and can be used for periodontal treatment against Streptococcus Gordonii. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The figure is a particle size characterization result diagram of the antibacterial photothermal / photodynamic nanoparticles in Example 1 (wherein Figure A is a transmission electron microscope image of ICGNPs nanoparticles, and Figure B is a particle size distribution diagram of ICG NPs nanoparticles);

[0025] Figure 2 The UV-visible absorption spectrum of the antibacterial photothermal / photodynamic nanoparticles in Example 1 at 250-900 nm;

[0026] Figure 3 The standard curve of different concentrations of indocyanine green in Example 1;

[0027] Figure 4 The in vitro photothermal performance results of ICG NPs nanoparticles in Example 1 (Figure A is a line graph of temperature changes at different concentrations, and Figure B is a line graph of temperature changes at different powers);

[0028] Figure 5 The plate count graphs of indocyanine green and ICG NPs nanoparticles at different concentrations in Example 1 (Figure A is the agar plate image of each group; Figure B is the survival rate of S. gordonii bacteria; * and **** represent P < 0.05 and P < 0.0001, respectively).

[0029] Figure 6 The figures are the anti-biofilm effects of indocyanine green and ICG NPs nanoparticles at different concentrations on Streptococcus gordonii in Example 1 (Figure A is the crystal violet staining of Streptococcus gordonii after different treatments; Figure B is the semi-quantitative analysis of the amount of biofilm of Streptococcus gordonii; ** and **** represent P < 0.01 and P < 0.0001, respectively).

[0030] Figure 7 This is a graph showing the reactive oxygen production of indocyanine green and ICG NPs nanoparticles at different concentrations in Example 1 under an inverted fluorescence microscope.

[0031] Figure 8This is a graph showing the hemolysis rate of ICG NPs nanoparticles at different concentrations in Example 1. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation methods described herein are only used to explain the present invention and are not used to limit the present invention.

[0033] The method for preparing antibacterial photothermal / photodynamic nanoparticles of the present invention is carried out in a light-proof environment and comprises the following steps:

[0034] 1) adding dipalmitoylphosphatidylcholine, cholesterol, distearoylphosphatidylethanolamine-polyethylene glycol, and indocyanine green into anhydrous ethanol to dissolve and obtain a liposome ethanol solution;

[0035] 2) adding the liposome ethanol solution into pure water to obtain a mixed solution;

[0036] 3) subjecting the mixed solution to ultrasonic crushing to obtain primary particles of liposome-encapsulated indocyanine green;

[0037] 4) dialyzing the primary particles of indocyanine green encapsulated by liposomes to obtain antibacterial photothermal / photodynamic nanoparticles of indocyanine green encapsulated by liposomes.

[0038] The mass ratio of dipalmitoylphosphatidylcholine, cholesterol and distearoylphosphatidylethanolamine-polyethylene glycol is (7-12): (2-6): (1-2).

[0039] The mass ratio of the liposome to indocyanine green is 10-20:1, and the liposome refers to the total amount of dipalmitoylphosphatidylcholine+cholesterol+distearoylphosphatidylethanolamine-polyethylene glycol.

[0040] In step 2), the concentration of indocyanine green in the mixed solution is 0.1-1 mg / mL.

[0041] The power of the ultrasonic crushing is 30% to 40%, and the time of the ultrasonic crushing is 5 to 10 minutes.

[0042] The distearoyl phosphatidylethanolamine-polyethylene glycol is distearoyl phosphatidylethanolamine modified with polyethylene glycol 2000.

[0043] The molecular weight cut-off of the dialysis is 8000-14000Da, and the dialysis time is 12-24h.

[0044] The antibacterial photothermal / photodynamic nanoparticles of indocyanine green encapsulated by liposomes are uniform spherical particles with a particle size of 100 to 300 nm.

[0045] The antibacterial photothermal / photodynamic nanoparticles prepared by the above preparation method.

[0046] The above-mentioned antibacterial photothermal / photodynamic nanoparticles are used in the preparation of drugs for treating and inhibiting periodontal Streptococcus Gordonii.

[0047] The present invention will be further described below in conjunction with the embodiments.

[0048] Example 1

[0049] Weigh 7 mg of dipalmitoylphosphatidylcholine, 2 mg of cholesterol, 1 mg of distearoylphosphatidylethanolamine-polyethylene glycol (all purchased from Xi'an Ruixi Biotechnology Co., Ltd.) and 1 mg of indocyanine green (Beijing Bailingwei Technology Co., Ltd.) and dissolve them in 1 ml of anhydrous ethanol. Make the mass ratio of liposomes to indocyanine green 10:1. Take another 9 ml of ultrapure water, and add the above mixed solution dropwise into the ultrapure water so that the concentration of indocyanine green is 0.1 mg / ml. The concentration is obtained by using an ultrasonic cell disruptor, ultrasonicating at 30% power for 10 minutes, and synthesizing the primary particles of liposomes encapsulating indocyanine green. Under light-proof conditions, the obtained mixed solution is transferred to an 8000Da dialysis bag and dialyzed overnight for 24 hours to remove unbound ICG and excipients, and obtain antibacterial photothermal / photodynamic nanoparticles of indocyanine green encapsulated by liposomes.

[0050] Example 2

[0051] Weigh 10 mg of dipalmitoylphosphatidylcholine, 3.5 mg of cholesterol, 1.5 mg of distearoylphosphatidylethanolamine-polyethylene glycol and 1 mg of indocyanine green and dissolve them in 1 ml of anhydrous ethanol. Make the mass ratio of liposomes to indocyanine green 15:1. Take another 4 ml of ultrapure water and add the above mixed solution dropwise into the ultrapure water so that the concentration of indocyanine green is about 0.2 mg / ml. The concentration is obtained by using an ultrasonic cell disruptor and ultrasonicating at 35% power for 8 minutes to synthesize the primary particles of liposome-encapsulated indocyanine green. Under light-proof conditions, the obtained mixed solution is transferred to a 10000Da dialysis bag and dialyzed overnight for 18 hours to remove unbound ICG and excipients to obtain antibacterial photothermal / photodynamic nanoparticles of indocyanine green encapsulated by liposomes.

[0052] Example 3

[0053] Weigh 12 mg of dipalmitoylphosphatidylcholine, 6 mg of cholesterol, 2 mg of distearoylphosphatidylethanolamine-polyethylene glycol and 1 mg of indocyanine green and dissolve them in 1 ml of anhydrous ethanol. Make the mass ratio of liposomes to indocyanine green 20:1. Take another 1 ml of ultrapure water and add the above mixed solution dropwise into the ultrapure water so that the concentration of indocyanine green is about 0.5 mg / ml. Use an ultrasonic cell disruptor to ultrasonicate at 40% power for 5 minutes to synthesize primary particles of liposome-encapsulated indocyanine green. Under light-proof conditions, transfer the obtained mixed solution to a 14000Da dialysis bag and dialyze it overnight for 12 hours to remove unbound ICG and excipients to obtain liposome-encapsulated indocyanine green nanoparticles.

[0054] The liposome nanoparticles obtained in Examples 1, 2 and 3 were physically and chemically characterized. The particle sizes of the liposome nanoparticles obtained in Examples 1, 2 and 3 were approximately 146 nm, 259 nm and 271 nm, respectively, the PDIs were 0.263, 0.279 and 0.294, and the encapsulation rates were approximately 93.7%, 88.3% and 83.1%, respectively. In the above embodiments, Example 1 is the best solution, and the liposome nanoparticles used in the following embodiments are all prepared from Example 1.

[0055] Test results and analysis

[0056] (1) Particle size analysis of antibacterial photothermal / photodynamic nanoparticles

[0057] The antibacterial photothermal / photodynamic nanoparticles obtained in Example 1 were physically and chemically characterized. First, the morphological characteristics of the prepared ICG NPs were observed using a transmission electron microscope from Hitachi, Japan. Then, the particle size of ICG NPs was analyzed using a dynamic light scattering particle size analyzer from Malvern, UK. The ultraviolet-visible absorption spectrum of ICGNPs at a wavelength of 250 to 900 nm was measured using a UV-visible spectrophotometer from Hitachi, Japan.

[0058] pass Figure 1 A transmission electron microscope image shows that the liposome nanoparticles ICG NPs obtained in Example 1 have a regular spherical structure, a particle size of about 150 nm, and good size uniformity.

[0059] pass Figure 1 B. From the results of dynamic light scattering, it can be seen that the hydrated particle size of the liposome nanoparticles ICG NPs obtained in Example 1 is about 146 nm, the polydispersity index (PDI) is 0.263, and the dispersibility and uniformity are good, which is convenient for quality control of nanoformulation production.

[0060] pass Figure 2The measurement results of the ultraviolet-visible spectrophotometer show that the ultraviolet absorption curve of the ICG NPs prepared in Example 1 contains the characteristic absorption peak of ICG at 780 nm, indicating that ICG has been successfully encapsulated into the liposomes to form a stable ICG NPs nano-load structure.

[0061] (2) Encapsulation efficiency of antibacterial photothermal / photodynamic nanoparticles

[0062] Figure 3 The standard curve of ICG at different concentrations (3-125 μg / ml) at 780 nm measured by ultraviolet spectrophotometer has a good linear relationship with the absorbance. The encapsulation amount of ICG was measured by ultraviolet spectrophotometer, and the results showed that the encapsulation rate of ICG in liposome nanoparticles ICG NPs was high, with an encapsulation rate of 93.7%.

[0063] (3) Photothermal properties of antibacterial photothermal / photodynamic nanoparticles

[0064] The photothermal efficiency of the antibacterial photothermal / photodynamic nanoparticles obtained in Example 1 was measured. PBS and ICG NPs solutions of different concentrations were irradiated with near-infrared light of 808 nm, and the temperature change curve of ICG NPs under near-infrared light of different powers for 10 min was detected. The temperature of the ICG NPs solution was detected every 30 seconds to evaluate the photothermal efficiency of ICG NPs.

[0065] Figure 4 A is a graph showing the photothermal heating effect of ICG NPs at different concentrations (6.25, 12.5, 25, 50, 100 μg / mL). The results show that ICG NPs have a higher photothermal efficiency than PBS, and its heating effect increases with increasing concentration.

[0066] Figure 4 B is different power (0.5W / cm 2 、0.6W / cm 2 , 0.7W / cm 2 , 0.8W / cm 2 , 0.9W / cm 2 , 1.0W / cm 2 ) under near-infrared light irradiation. The results show that the temperature of the ICG NPs solution increases with the increase of power, indicating that ICG NPs has a good heat generation effect.

[0067] When irradiated with near-infrared light for 10 minutes, the maximum temperature of the ICG NPs solution at a concentration of 50 μg / ml was greater than 50°C, while the temperature of the solution in the control group did not increase significantly. This indicates that ICG NPs have a good bactericidal effect without damaging normal tissues. Therefore, ICG NPs at a concentration of 50 μg / ml were selected for subsequent studies.

[0068] (4) In vitro antibacterial properties of antibacterial photothermal / photodynamic nanoparticles

[0069] The antibacterial photothermal / photodynamic nanoparticles ICG NPs obtained in Example 1 were characterized for their in vitro antibacterial properties. First, the revived S. gordonii was inoculated on a BHI agar plate and cultured overnight at 37°C under aerobic conditions (5% O2, 85% N2, 10% CO2). When a single colony grew out, the S. gordonii single colony was transferred to 5 ml of liquid culture medium and continued to be cultured until the logarithmic growth phase. The S. gordonii bacterial suspension was prepared into 1×10 7 CFU / mL for later use. The S.gordonii bacterial suspension was centrifuged at 8000rpm for 5min, incubated with 1ml PBS (control group), ICG at different concentrations (5, 10, 15, 20μg / ml) and liposome nanoparticles ICGNPs at 37℃ in the dark for 2h, and then the sample was centrifuged at 6000rpm for 5min and washed three times with PBS. 100μl of the sample was transferred to a 96-well plate and washed with 1W / cm 2 Irradiate with near-infrared light for 10 minutes, and after continuous dilution, take 10 μl of bacterial solution and add it evenly on the BHI agar plate, and culture it overnight under aerobic conditions at 37°C. Count the colonies after they grow. The inhibition rate is calculated. The experimental results are shown in the figure below. Figure 5 shown.

[0070] Depend on Figure 5 It can be seen that ICG NPs are exposed to 1W / cm 2 After 10 minutes of near-infrared light irradiation, the bactericidal ability of lower concentrations of ICG was weaker than that of the control group. The antibacterial activity was only 43% at ICG 15μg / ml, while the antibacterial efficiency reached 93% at ICG concentration of 20μg / ml. The above results showed that the bacterial activity of S.gordonii decreased with the increase of ICG concentration. Compared with free ICG, the antibacterial effect of ICG NPs nanoparticles is more significant, and its antibacterial efficiency can reach 99%. Therefore, the significant decrease in colony counts under 808nm irradiation shows that ICG NPs can play a good bactericidal role after near-infrared light irradiation, and show excellent in vitro antibacterial effect on Streptococcus gordonii.

[0071] (5) In vitro anti-biofilm properties of antibacterial photothermal / photodynamic nanoparticles

[0072] The antibacterial photothermal / photodynamic nanoparticles ICG NPs obtained in Example 1 were tested for their anti-biofilm activity. First, the biofilm of Streptococcus gordonii was cultured in a constant temperature incubator, and 100 μl PBS, ICG at different concentrations (5, 10, 15, 20 μg / ml) and ICG NPs were added and incubated for 6 h, and the biofilms of the ICG group and ICG NPs group were irradiated with 1 W / cm 2 The treatment was performed by near-infrared laser irradiation for 10 min. The biofilm was then stained with crystal violet for 20 min, and the OD value at 600 nm was measured using a microplate reader to evaluate the anti-biofilm effect of ICG NPs.

[0073] Figure 6 A is the crystal violet staining image of the biofilm. Figure 6 B is a semi-quantitative analysis of the biofilm biomass of Streptococcus gordonii. Compared with the control group, the biofilm biomass of S.gordonii gradually decreased with the increase of ICG concentration. When the ICG concentration increased from 5μg / ml to 15μg / ml, the inhibition rate of S.gordonii biofilm increased from 27% to 44%. The results showed that the inhibitory effect of ICG on biofilm formation was concentration-dependent. When ICG NPs were used at 1W / cm 2 After 10 minutes of near-infrared light irradiation, the inhibition rate of S. gordonii biofilm (87%) was more significant than that of 20 μg / ml ICG alone (73%). Therefore, compared with free ICG, ICG NPs showed a better anti-biofilm effect on S. gordonii.

[0074] (6) In vitro detection of reactive oxygen species (ROS) of antibacterial photothermal / photodynamic nanoparticles

[0075] The S. gordonii suspension in the logarithmic growth phase was incubated with the control group (PBS), ICG at different concentrations (5, 10, 15, 20 μg / ml), and ICG NPs for 2 h. 2 After near-infrared laser irradiation for 10 min, the ROS generation after different treatments was observed under an inverted fluorescence microscope using a ROS probe, dichlorofluorescein diacetate (DCFH-DA).

[0076] Figure 7The images of reactive oxygen production of ICG and ICG NPs at different concentrations were observed by inverted fluorescence microscopy. The presence of reactive oxygen species was almost undetectable in the blank control group. When free ICG was irradiated with 808nm laser, the fluorescence intensity gradually increased with the increase of ICG concentration, indicating that the generation of ROS was positively correlated with the concentration of ICG, while the ROS generation of ICG NPs was still higher than that of free ICG. ICG NPs can produce more reactive oxygen species.

[0077] (7) Biocompatibility of antibacterial photothermal / photodynamic nanoparticles

[0078] Arterial blood of SD rats was collected and red blood cells were prepared into a 2% red blood cell suspension for later use. Ultrapure water was used as the positive control group and PBS was used as the negative control group. ICG NPs solutions of different concentrations (50, 25, 12.5, 6.25 μg / ml), ultrapure water, PBS and 2% red blood cell suspension were mixed in a 1:1 ratio. Incubate at 37°C in the dark for 4 hours, centrifuge at 1500 rpm for 10 minutes, and detect the OD value of the supernatant at 540 nm using an enzyme marker.

[0079] Figure 8 The hemolysis images of ICG NPs nanoparticles at different concentrations. The red blood cell damage and hemoglobin leakage were obvious in the positive control group, while no red blood cell damage was observed in other groups. As the concentration of ICG NPs nanoparticles increased, the absorbance at OD540 nm gradually increased, and the damage to red blood cells also gradually increased. However, at the highest concentration within the research range (50μg / ml), the hemolysis rate of ICG NPs nanoparticles was still less than 5%. The results showed that ICG NPs nanoparticles have good biocompatibility.

[0080] Although the above embodiment describes the present invention in detail, it is only a part of the embodiments of the present invention rather than all the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A method for preparing antibacterial photothermal / photodynamic nanoparticles, characterized in that: The preparation method is carried out in a light-proof environment and comprises the following steps: 1) adding dipalmitoylphosphatidylcholine, cholesterol, distearoylphosphatidylethanolamine-polyethylene glycol, and indocyanine green into anhydrous ethanol to dissolve to obtain a liposome ethanol solution; 2) adding the liposome ethanol solution into pure water to obtain a mixed solution; 3) subjecting the mixed solution to ultrasonic crushing to obtain primary particles of liposome-encapsulated indocyanine green; 4) dialyzing the primary particles of indocyanine green encapsulated by liposomes to obtain antibacterial photothermal / photodynamic nanoparticles of indocyanine green encapsulated by liposomes.

2. The method for preparing antibacterial photothermal / photodynamic nanoparticles according to claim 1, characterized in that: The mass ratio of dipalmitoylphosphatidylcholine, cholesterol and distearoylphosphatidylethanolamine-polyethylene glycol is (7-12): (2-6): (1-2).

3. The method for preparing antibacterial photothermal / photodynamic nanoparticles according to claim 2, characterized in that: The mass ratio of the liposome to indocyanine green is 10-20:1, and the liposome refers to the total amount of dipalmitoylphosphatidylcholine+cholesterol+distearoylphosphatidylethanolamine-polyethylene glycol.

4. The method for preparing antibacterial photothermal / photodynamic nanoparticles according to claim 1, characterized in that: In step 2), the concentration of indocyanine green in the mixed solution is 0.1-1 mg / mL.

5. The method for preparing antibacterial photothermal / photodynamic nanoparticles according to claim 1, characterized in that: The power of the ultrasonic crushing is 30% to 40%, and the time of the ultrasonic crushing is 5 to 10 minutes.

6. The method for preparing antibacterial photothermal / photodynamic nanoparticles according to claim 1, characterized in that: The distearoyl phosphatidylethanolamine-polyethylene glycol is distearoyl phosphatidylethanolamine modified with polyethylene glycol 2000.

7. The method for preparing antibacterial photothermal / photodynamic nanoparticles according to claim 1, characterized in that: The molecular weight cut-off of the dialysis is 8000-14000Da, and the dialysis time is 12-24h.

8. The method for preparing the antibacterial photothermal / photodynamic nanoparticles according to any one of claims 1 to 7, characterized in that: The antibacterial photothermal / photodynamic nanoparticles of indocyanine green encapsulated by liposomes are uniform spherical particles with a particle size of 100 to 300 nm.

9. Antibacterial photothermal / photodynamic nanoparticles prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the antibacterial photothermal / photodynamic nanoparticles according to claim 9 in the preparation of a drug for treating and inhibiting periodontal Streptococcus gordonii.

Images