Aluminum adjuvant coated PLGA (poly (lactic-co-glycolic acid)) nanoparticles and application thereof

Abstract

The invention discloses an aluminum adjuvant coated PLGA (poly (lactic-co-glycolic acid)) nanoparticle and application thereof, a nanoscale aluminum adjuvant is prepared firstly, and then the aluminum adjuvant coated PLGA nanoparticle is prepared. The prepared nano-aluminum-coated PLGA nanoparticles can effectively activate antigen presenting cells and promote antigen presentation, so that humoral immunity and cellular immunity processes of an organism are activated at the same time, the tumor immunotherapy effect is enhanced, and the nano-aluminum-coated PLGA nanoparticles have high clinical use value.

Description

Technical Field

[0001] The invention belongs to the technical field of biomedicine, and specifically relates to PLGA nanoparticles coated with aluminum adjuvant and application of the nanoparticles as vaccine adjuvants. Background Art

[0002] Vaccine adjuvants refer to immune stimulants that enhance and regulate the immune response of vaccine antigens. When used together with antigens, they can produce a stronger immune response. The development of adjuvants has lasted for more than a hundred years. Traditional inactivated vaccines basically use complex adjuvants based on aluminum salts. In recent years, new vaccines such as recombinant vaccines, genetic engineering vector vaccines, and nucleic acid vaccines have been gradually developed. These vaccines generally have the problem of low immunogenicity, so a variety of broad-spectrum and highly efficient new vaccine adjuvants have been successfully developed. According to their different mechanisms of action, they can be divided into new oil emulsion adjuvants, liposome adjuvants, CpG oligonucleotide adjuvants, cytokine adjuvants, nanoadjuvants, polysaccharide adjuvants, and composite system adjuvants. At present, the human vaccine adjuvants on the market include aluminum salts, MF59, virus-like particles, AS04, AS03, AS01, CpG 1018, and Matrix-M for emergency use of the new crown.

[0003] Aluminum adjuvants, as the most widely used type of adjuvant, usually refer to aluminum hydroxide, aluminum phosphate, potassium aluminum sulfate, amorphous aluminum hydroxyphosphate sulfate and aluminum-magnesium mixtures with particle sizes at the micron level. Currently, the aluminum adjuvants on the market mainly include aluminum hydroxide adjuvants (trade name: Rehydragel TM ) and aluminum phosphate adjuvant (trade name: Aluminum adjuvants work by adsorbing antigens onto their surfaces. Their combined use can increase the humoral immune response induced by vaccine antigens by several times or even dozens of times without inducing serious side effects such as fever.

[0004] Poly(lactide-co-glycolide) (PLGA) is a biomaterial formed by random polymerization of two monomers, lactide and glycolide. It has good biocompatibility and biodegradability and has been approved by the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA) for the preparation of drug delivery systems. At present, vaccine controlled release delivery systems based on PLGA nanoparticles have been widely studied. PLGA nanoparticles can not only encapsulate antigens inside them, but also adsorb protein antigens through hydrophobic forces. Through reasonable design, the application range of PLGA nanoparticles can be greatly enriched and their functionality can be improved, which has excellent application prospects.

[0005] Although aluminum adjuvants approved for marketing have good safety and efficacy and are widely used, the particle size of aluminum adjuvants is 1-10 μm. The larger particle size makes it difficult for aluminum salts to be taken up by cells and cannot help antigens complete the lysosomal escape process, making it difficult for antigens to stimulate CD8 through the MHC I cross-presentation process. + The Th1 type cellular immune response process mediated by T cells. Currently, most aluminum adjuvant vaccines on the market can only induce Th2 type humoral immune response, which is less effective for tumor immunotherapy. The lack of safe and efficient new aluminum salt adjuvants limits its clinical application. Summary of the invention

[0006] One of the purposes of the present invention is to provide a PLGA nanoparticle, comprising a core and a shell, wherein the core is made of a lactide-co-glycolide copolymer, and the shell is made of an aluminum adjuvant and a stabilizer;

[0007] The molecular weight of the lactide-glycolide copolymer is 4000-240000, and the molar ratio of lactide to glycolide in the lactide-glycolide copolymer is 1:99-99:1

[0008] Furthermore, the particle size of the aluminum adjuvant is 0.01-1 μm.

[0009] Furthermore, the aluminum adjuvant is AlOOH, Al(OH)3 or Al2O3·3H2O.

[0010] Furthermore, the inner core is loaded with a drug that enhances antigen presentation.

[0011] Furthermore, the drug for enhancing antigen presentation is a Toll-like receptor agonist.

[0012] Furthermore, the stabilizer is polyvinyl alcohol (PVA), polyvinyl pyrrolidone (PVP) or carboxymethyl cellulose (CMC).

[0013] Toll-like receptors (TLRs) are innate immune receptors that are directly or indirectly responsible for detecting pathogen-associated molecular patterns (PAMPs) and responding to PAMPs by activating innate and adaptive immune pathways. Naturally occurring and synthetic TLR agonists can utilize these endogenous immune signaling pathways to enhance and regulate vaccine responses, thereby functioning as vaccine adjuvants. The Toll-like receptor family mainly includes TLR1, TLR2, TLR4, TLR5, TLR6, TLR10, which are expressed on the cell membrane surface and can recognize pathogen membrane components, and TLR3, TLR7, TLR8, and TLR9, which are expressed on the endoplasmic reticulum and lysosomal membrane surfaces of cells and can recognize pathogen nucleic acid components. In the present invention, the Toll-like receptor agonists that can be used include TLR1 / 2 agonists (such as Diproovocim, CU-T12-9), TLR4 agonists (such as Neoseptin 3, monophospholipid A, Euodenine A derivatives), TLR2 / 6 agonists (FSL-1), TLR7 / 8 agonists (such as Imiquimod, Resimod, PF-4878691, Selgantolimod, Telratolimod, Vesatolimod, Motolimod), TLR9 agonists, etc. In one embodiment of the present invention, Imiquimod is selected as a model drug and loaded by the above-mentioned PLGA nanoparticles.

[0014] The second object of the present invention is to provide a method for preparing the above-mentioned PLGA nanoparticles, comprising the following steps:

[0015] Step 1, dissolving PLGA in a mixed solution of dichloromethane and methanol as an oil phase;

[0016] Step 2, using aluminum adjuvant solution as the aqueous phase;

[0017] Step 3, under ice bath and ultrasonic conditions, dropwise adding the oil phase into the water phase, and continuously ultrasonicating to obtain an O / W emulsion;

[0018] Step 4, pouring the O / W emulsion into the stabilizer solution, stirring to remove the organic solvent, centrifuging, removing the supernatant, and obtaining the PLGA nanoparticles.

[0019] In one embodiment of the present invention, PLGA and imiquimod (R837) are dissolved together in a mixed solution of dichloromethane and methanol as an oil phase, and then the subsequent preparation is performed.

[0020] The third object of the present invention is to provide the use of the above-mentioned PLGA nanoparticles as a vaccine adjuvant.

[0021] The present invention prepares PLGA nanoparticles coated with nano-aluminum adjuvants. The electrostatic effect, ligand exchange effect of the nano-aluminum adjuvant and the hydrophobic effect of PLGA are utilized to enable the nano-aluminum-coated PLGA nanoparticles to effectively adsorb antigens and achieve efficient antigen delivery and lysosomal escape in cells. At the same time, Toll-like receptor 7 can be activated by further encapsulating imiquimod (R837), thereby effectively activating antigen presenting cells and synergistically enhancing the body's cellular immune response process.

[0022] Beneficial effects:

[0023] (1) The present invention prepares a nano-scale aluminum adjuvant. Compared with the traditional micron-scale aluminum adjuvant material, the nano-aluminum adjuvant can be effectively taken up by cells, thereby assisting the lysosomal escape of vaccine antigens and the antigen presentation process.

[0024] (2) The preparation process of the nano-aluminum-coated PLGA nanoparticles provided by the present invention is simple and has good reproducibility; compared with commercially available aluminum adjuvants, the nano-adjuvant of the present invention has a higher antigen loading capacity and high stability, and is easy for clinical transformation.

[0025] (3) The PLGA nanoparticles prepared by the present invention can be loaded with other drugs at the same time, such as the Toll-like receptor 7 agonist imiquimod, to exert a synergistic immune effect.

[0026] (4) The nano-aluminum-coated PLGA nanoparticles prepared by the present invention can effectively activate antigen presenting cells and promote antigen presentation, thereby activating the body's humoral immunity and cellular immunity processes at the same time, enhancing the tumor immunotherapy effect, and have high clinical use value. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The particle size distribution and potential distribution of aluminum oxyhydroxide (AlOOH) are shown in Figure 2.

[0028] Figure 2 Figure 2 shows the particle size of R837@AP nanoadjuvant coated with different concentrations of aluminum adjuvant.

[0029] Figure 3 This is the particle size distribution diagram of R837@AP nanoadjuvant.

[0030] Figure 4 This is a transmission electron microscopy image of R837@AP nanoadjuvant.

[0031] Figure 5 This is the result of the stability investigation experiment of R837@AP nanoadjuvant.

[0032] Figure 6In the figure, the left figure shows the antigen adsorption rate results of R837@AP nanoadjuvants with different w / w, and the right figure shows the antigen adsorption rate results of R837@AP nanoadjuvant and commercially available aluminum adjuvant when w / w=1:8.

[0033] Figure 7 The results show the changes in the viability of DC2.4 cells after incubation with aluminum adjuvant-coated PLGA nanoparticles (AP), R837, and aluminum adjuvant-coated PLGA nanoparticles loaded with R837 (R837@AP) for 24 hours.

[0034] Figure 8 These are the results of investigating the lysosomal escape ability of R837@AP / OVA nanovaccine. DETAILED DESCRIPTION

[0035] The present invention uses aluminum adjuvant dissolved in water as the aqueous phase, and PLGA and imiquimod dissolved in dichloromethane-methanol as the oil phase to prepare nano-aluminum-coated PLGA nanoparticles, and loads the Toll-like receptor 7 agonist imiquimod in the nanoparticles to enhance antigen presentation and synergistically activate cellular immunity for tumor immunotherapy. The preparation process includes the following steps:

[0036] Step 1, dissolving PLGA and imiquimod in a mixed solution of dichloromethane and methanol as an oil phase;

[0037] The concentration of PLGA is 10-50 mg / mL, preferably 25 mg / mL; the concentration of imiquimod is 1.5-5 mg / mL, preferably 3.25 mg / mL; the volume ratio of dichloromethane to methanol is 2:1;

[0038] Step 2, using an aluminum adjuvant solution as the aqueous phase, wherein the concentration of the aluminum adjuvant is 1 to 20 mg / mL, preferably 5 mg / mL;

[0039] Step 3, under ice bath and ultrasonic conditions, dropwise add the oil phase into the water phase, and continue ultrasonication for 10 to 30 minutes to obtain an O / W emulsion;

[0040] Step 4, pouring the O / W emulsion into the PVA solution, stirring to remove the organic solvent, centrifuging, removing the supernatant, washing the precipitate with deionized water, and resuspending to obtain PLGA nanoparticles coated with aluminum adjuvant;

[0041] The volume ratio of the oil phase, the water phase and the PVA solution is 1:10:50.

[0042] Specifically, the preparation method of aluminum oxyhydroxide (AlOOH) is as follows: adding NaOH solution to AlCl3·6H2O solution under stirring conditions, adjusting the pH of the mixed solution to weak acidity with NaOH solution, continuously stirring, ultrasonicating, ultrafiltering and replacing the buffer system with neutral deionized water to obtain aluminum oxyhydroxide nanoparticles. The concentration of AlCl3·6H2O solution is 2-20 mg / mL, the concentration of NaOH solution is 0.04-0.50 mol / L, the adjusted pH is 5.0-6.0, and the continuous stirring time is 10-60 min.

[0043] Specifically, the preparation method of aluminum hydroxide (Al(OH)3) is as follows: adding NaOH solution to AlCl3 solution under stirring conditions, adjusting the pH of the mixed solution to weak acidity with NaOH solution, and obtaining Al(OH)3 nanoparticles. The content of AlCl3 solution is 1-95%, the content of NaOH solution is 1-75%, the adjusted pH is 5.8, and the stirring speed is 1-500r / min.

[0044] Specifically, the preparation method of hydrated aluminum oxide (Al2O3·3H2O) is as follows: anhydrous AlCl3 crystals are completely dissolved into a transparent solution, ammonia is introduced under stirring conditions, and the reaction is stopped when the pH is alkaline to obtain Al2O3·3H2O. The temperature of the AlCl3 solution is maintained at 10-90°C, and the pH is adjusted to 7.0-10.0.

[0045] The preferred embodiments of the present invention will be described in detail below in conjunction with examples. It should be understood that the following examples are provided only for the purpose of illustration and are not intended to limit the scope of the present invention. Those skilled in the art may make various modifications and substitutions to the present invention without departing from the purpose and spirit of the present invention.

[0046] Unless otherwise specified, the experimental methods used in the following examples are conventional methods.

[0047] Unless otherwise specified, the materials and reagents used in the following examples can be obtained from commercial sources.

[0048] Poly(lactide-co-glycolide) (PLGA, Mw 38000-54000 Da, LG 50:50).

[0049] Example 1

[0050] 1. Preparation of aluminum adjuvant

[0051] 1.1 Preparation of aluminum oxyhydroxide (AlOOH)

[0052] 400 mg of AlCl3·6H2O was weighed and dissolved in 40 mL of deionized water to obtain a 1% AlCl3·6H2O solution. Under room temperature and stirring conditions, 30 mL of 0.12 mol / L NaOH solution was added to 30 mL of 1% AlCl3·6H2O solution, and 0.04 mol / L NaOH solution was added dropwise after mixing evenly. The addition was stopped when the pH of the solution reached 5.0-6.0, and stirring was continued for 30 min. After that, the solution was ultrasonically treated (ice bath) with an ultrasonic cell disruptor, and finally, an ultrafiltration tube (MWCO 3 kDa) was used to remove excess ion residues in the solution and the buffer system was replaced with deionized water with a pH of 7.0 to obtain AlOOH nanoparticles.

[0053] The particle size, polydispersity index (PDI) and potential were measured by nanoparticle size potentiometer. Figure 1 As shown, the AlOOH nanoparticle solution has a light blue opalescence, a particle size of 53.0±5.9 nm, a PDI of 0.175±0.023, and a potential of +40.1±0.5 mV.

[0054] 1.2 Preparation of aluminum hydroxide (Al(OH)3)

[0055] Weigh 32g AlCl3 and dissolve it in 40mL deionized water to obtain 80% AlCl3 solution. Weigh 16g NaOH and dissolve it in 40mL deionized water to obtain 40% NaOH solution. Add AlCl3 solution into a reaction vessel and stir at room temperature at a stirring speed of 150-200r / min, and add NaOH solution dropwise into AlCl3 solution until pH reaches 5.8 to obtain Al(OH)3 solution.

[0056] 1.3 Preparation of hydrated aluminum oxide (Al2O3·3H2O)

[0057] Take 32g of anhydrous AlCl3 crystals and put them into a three-necked flask. Add a certain amount of benzene to moisten it. Then slowly add an appropriate amount of anhydrous ethanol. AlCl3 is completely dissolved into a transparent solution. Keep the temperature at 60-70℃. Then stir and pass ammonia to promote the reaction. The reaction is continued for 2h. The white solid in the reflux reactor gradually increases, and the reaction stops when the pH is 8. Then vacuum filter and distill the filtrate in a water bath. Take the distilled sample and dissolve it in deionized water for hydrolysis to obtain Al2O3·3H2O.

[0058] 2. Preparation of coated PLGA nanoparticles

[0059] Weigh 50 mg PLGA and 6.5 mg R837 and dissolve them in 2 mL dichloromethane-methanol (2:1, v / v) to obtain the oil phase; dilute the AlOOH solution to the appropriate concentration (1.0, 2.5, 5.0, 10.0, 20.0 mg / mL) as the aqueous phase. Add 2 mL of the oil phase to 20 mL of the aqueous phase under ice bath and ultrasonic conditions (ultrasonic power of 300 W, with a parameter cycle of ultrasonic 3s and then stop 3s), and continue ultrasonication for 15 minutes to obtain an O / W type emulsion, which is then poured into 100 mL of 1% PVA solution and stirred overnight to remove the organic solvent. The solution is then centrifuged at 12000 r / min and the precipitate is collected and washed with deionized water, repeated 3 times to remove excess, PVA and unencapsulated R837, and resuspended to obtain R837@AP nanoadjuvant.

[0060] The performance of the emulsion droplets is a key factor in the solvent evaporation method, and the concentration of AlOOH will affect the mechanical strength of the interfacial film and thus the size of the emulsion droplets. This example investigates the difference in particle size of R837@AP prepared when the concentration of AlOOH in the aqueous phase is 1.0, 2.5, 5.0, 10.0, and 20.0 mg / mL. Figure 2 It can be seen that the particle size of R837@AP decreases first and then increases with the increase of AlOOH concentration. When the concentration is 5.0 mg / mL, the particle size of R837@AP prepared is the smallest and there is no large particle precipitation after centrifugation. Therefore, the R837@AP used in subsequent experiments is prepared using 5.0 mg / mL AlOOH solution.

[0061] R837@AP prepared using 5.0 mg / mL AlOOH solution was diluted 100 times with deionized water to obtain 1 mL of sample dilution, and its particle size, PDI and potential were measured at 25 °C using a nanoparticle size potentiometer. Figure 3 As shown, the particle size of R837@AP nanoadjuvant is 334±2.5nm, PDI is 0.225±0.010, and the potential is +26.7±0.3mV.

[0062] R837@AP prepared with 5.0mg / mL AlOOH solution was diluted with deionized water to an appropriate multiple, 10μL was pipetted and dropped onto the copper mesh, and allowed to stand for 3min. Then 0.1wt% phosphotungstic acid solution was added for dyeing for 2-3min, the residual dye solution was dried with filter paper, and a small amount of deionized water was added to wash away the excess phosphotungstic acid. The copper mesh was dried under an infrared lamp, observed under an electron microscope, and photographed. Figure 4 As shown, the nanoparticles as a whole present a spherical core-shell structure with a rough surface, which indicates that the prepared nanoadjuvant has a suitable particle size and potential, and has a large specific surface area, which is conducive to antigen delivery.

[0063] R837@AP prepared freshly using 5.0 mg / mL AlOOH solution was stored in a refrigerator at 4°C. The appearance of the solution was observed every 7 days, and a small amount of the solution was diluted 100 times with deionized water. The particle size and PDI changes of 1 mL of the sample dilution were measured at 25°C using a nanoparticle size potentiometer. Figure 5 As shown, when the R837@AP nanoadjuvant was placed in a 4°C environment, there was no significant difference in the particle size test results within 30 days, and the appearance of the solution was observed to show no stratification or large particle precipitation, indicating that the prepared nanoadjuvant has good stability.

[0064] Test Example 1

[0065] 10 mg of OVA protein was weighed and dissolved in 2 mL of deionized water to obtain an antigen mother solution. 150 μL of the carrier R837@AP prepared in Example 1 and 150 μL of the antigen solution were mixed in a centrifuge tube according to a certain mixing ratio (w / w), and vortexed for more than 1 h at room temperature to ensure sufficient mixing. The mixed solution was then centrifuged (4°C, 12000 r / min, 10 min), the supernatant was diluted and the protein content was determined by the BCA method, and the antigen adsorption rate (AE) was calculated according to formula (1).

[0066]

[0067] Among them, W total is the amount of antigen input in the mixed system, W free is the amount of free antigen in the supernatant.

[0068] In addition, the same method was used to determine the commercial aluminum adjuvant (Imject TM The antigen adsorption capacity of Alum Adjuvant was used as a control.

[0069] like Figure 7 As shown in the middle left figure, when the amount of carrier in the mixed system is greater than the amount of antigen (w / w ≥ 1), the antigen adsorption rate is high; when mixed at w / w = 10:1 and w / w = 8:1, R837@AP can completely adsorb the antigen, and its antigen adsorption rate can reach 98.9±2.1% at w / w = 4:1; when the amount of antigen in the mixed system is greater than the amount of carrier (w / w < 1), the antigen adsorption rate of R837@AP is lower than 80.0%, and it reaches adsorption saturation at w / w = 1:8. R837@AP nanoadjuvant and commercial aluminum adjuvant were mixed with OVA antigen at w / w = 1:8, and the maximum antigen adsorption amount of the two adjuvants was calculated, as shown in the figure below. Figure 6 As shown in the middle right figure, 1 mg R837@AP can adsorb 3.1±0.3 mg OVA antigen, which is about 2.1 times the adsorption capacity of commercially available aluminum adjuvants, which also proves that R837@AP has a high antigen loading capacity.

[0070] Test Example 2

[0071] 50 mg of PLGA was dissolved in 2 mL of dichloromethane-methanol (2:1, v / v) to obtain an oil phase, and the AlOOH solution was diluted to 5 mg / mL as the aqueous phase. 2 mL of the oil phase was added to 20 mL of the aqueous phase under ice bath and ultrasonic conditions, and the ultrasonication was continued for 15 min to obtain an O / W type Pickering emulsion, which was then poured into 100 mL of 1% PVA solution and stirred overnight to remove the organic solvent. The solution was centrifuged at 12000 r / min, the precipitate was collected, washed 3 times with deionized water to remove excess AlOOH and PVA, and resuspended to obtain an aluminum adjuvant-coated PLGA nanoparticle solution (AP).

[0072] DC2.4 cells in the logarithmic growth phase were counted at 5×10 3 The cells were seeded at a density of 100 / well in a 96-well plate and cultured in a CO2 incubator for 24 hours. Then, different concentrations of aluminum oxyhydroxide solution (AlOOH), aluminum adjuvant-coated PLGA nanoparticle solution (AP), R837 solution, and aluminum adjuvant-coated R837-loaded PLGA nanoparticle solution (R837@AP) were incubated with DC2.4 cells for 24 hours, and cell viability was determined by MTT assay.

[0073] like Figure 7 As shown, the cell safety of positively charged carriers of AlOOH and AP was first evaluated on DC2.4 cells. When the concentration of AlOOH was as high as 500 μg / mL, the cell survival rate of the AlOOH group was 81.1%, and the cell survival rate of the AP group was maintained above 90.0%, with no obvious cytotoxicity. Next, the cell safety of free R837 and R837@AP was evaluated. Free R837 had a high toxic effect on DC cells, and after R837 was loaded into the nanocarrier, the cell survival rate was high even at a higher concentration, indicating that the R837@AP nanoadjuvant has a high cell safety.

[0074] Test Example 3

[0075] Weigh 2 mg FITC and dissolve it in 100 μL DMSO to obtain a 20.0 mg / mL FITC solution. Weigh 40 mg OVA protein and dissolve it in 2 mL pH 9.0 sodium carbonate-sodium bicarbonate buffer (0.05 mol / L) to obtain a 20.0 mg / mL OVA solution. Add the FITC solution dropwise to the OVA solution at room temperature and in the dark, stir and react for 24 hours, dialyze in pure water for 12 hours, and freeze-dry to obtain OVA-FITC. Weigh 2 mg OVA-FITC and dissolve it in 1 mL deionized water to obtain a 2.0 mg / mL free OVA-FITC mother solution. Mix R837@AP and OVA-FITC at a ratio of 4:1 (w / w), vortex and oscillate at room temperature for more than 1 hour, and prepare a 1.0 mg / mL R837@AP / OVA-FITC mother solution.

[0076] DC2.4 cells in the logarithmic growth phase were counted at 1×10 5 The cells were inoculated at a density of 100 / dish in a 35 mm laser confocal culture dish. After culturing for 24 hours, the culture medium was removed and the cells were washed twice with PBS. 500 μL R837@AP / OVA-FITC (5 μg / mL) was added to the culture dish and incubated with the cells for 4 hours and 9 hours. The liquid was removed and the cells were washed three times with PBS. The cells were stained with Lyso-Tracker Red lysosomal red fluorescent probe at 37°C for 45 minutes, and then washed three times with PBS. The fluorescence distribution on DC2.4 cells was observed with CLSM and photographed.

[0077] like Figure 8 As shown in the figure, OVA antigen can be taken up into lysosomes with the help of R837@AP after about 4 hours of interaction with cells, and the colocalization coefficient reaches 0.92. After 9 hours of interaction, the green fluorescence of the antigen is mainly seen in the cytoplasm, and the colocalization coefficient drops to 0.56, indicating that the nanoadjuvant can promote the lysosomal escape of the antigen.

Claims

1. A PLGA nanoparticle, characterized in that: It comprises a core and an outer shell, wherein the core is made of a lactide-glycolide copolymer, and the outer shell is made of an aluminum adjuvant and a stabilizer; The molecular weight of the lactide-glycolide copolymer is 4000-240000, and the molar ratio of lactide to glycolide in the lactide-glycolide copolymer is 1:99-99:

1.

2. The PLGA nanoparticle according to claim 1, characterized in that The particle size of the aluminum adjuvant is 0.01-1 μm.

3. The PLGA nanoparticle according to claim 2, characterized in that The aluminum adjuvant is AlOOH, Al(OH)3 or Al2O3·3H2O.

4. The PLGA nanoparticle according to claim 1, characterized in that The inner core is loaded with a drug that enhances antigen presentation.

5. The PLGA nanoparticle according to claim 4, characterized in that The drug for enhancing antigen presentation is a Toll-like receptor agonist.

6. The PLGA nanoparticle according to claim 1, characterized in that The stabilizer is polyvinyl alcohol, polyvinyl pyrrolidone or carboxymethyl cellulose.

7. The method for preparing PLGA nanoparticles according to claim 1, characterized in that: The following steps are involved: Step 1, dissolving the lactide-co-glycolide copolymer in a mixed solution of dichloromethane and methanol as an oil phase; Step 2, using aluminum adjuvant solution as the aqueous phase; Step 3, under ice bath and ultrasonic conditions, dropwise adding the oil phase into the water phase, and continuously ultrasonicating to obtain an O / W emulsion; Step 4, pouring the O / W emulsion into the stabilizer solution, stirring to remove the organic solvent, centrifuging, removing the supernatant, and obtaining the PLGA nanoparticles.

8. Use of the PLGA nanoparticles according to any one of claims 1 to 6 in the preparation of vaccine adjuvants.

Images