Quantum dot modified group B neisseria meningitidis and vaccine preparation method thereof

Abstract

The invention provides quantum dot modified group B neisseria meningitidis and a preparation method of a vaccine of the quantum dot modified group B neisseria meningitidis. The preparation method comprises the following steps: taking corn straws and sunflower straws as a straw mixture according to a weight ratio of (1-1.5): 1, putting the straw mixture, an escherichia coli DH5alpha cell membrane and urea into water according to a weight ratio of 100: 100: 1, carrying out high-temperature heating reaction, and filtering and dialyzing reactants to prepare aminated quantum dots; extruding the aminated quantum dots and a group B neisseria meningitidis cell membrane through a liposome extruder according to a weight ratio of (8-10): 1, and centrifuging to obtain cell membrane hybrid aminated quantum dots; and co-incubating the cell membrane hybrid aminated quantum dots and the group B neisseria meningitidis to obtain the cell membrane hybrid aminated quantum dots. The group B neisseria meningitidis is modified by adopting the specific quantum dots, the toxicity of the modified group B neisseria meningitidis is obviously reduced, and the modified group B neisseria meningitidis is expected to be applied to related fields of vaccines and the like.

Description

Technical Field

[0001] This invention relates to the field of bioengineering technology, specifically to quantum dot-modified group B Neisseria meningitidis and its vaccine preparation method. Background Technology

[0002] Group B Neisseria meningitidis is a Gram-negative diplococcus that adheres to the nasopharyngeal mucosa via pili. Once it enters the bloodstream, it can cause bacteremia or sepsis, and may even cross the blood-brain barrier, leading to purulent encephalomyelitis.

[0003] Currently, the main strategy for attenuating the virulence of serogroup B Neisseria meningitidis is genetic engineering modification, such as deleting or inactivating genes directly related to pathogenicity, or modifying regulatory genes to reduce the expression level of virulence factors or alter their expression timing. However, these methods require extensive exploratory experiments and are quite challenging. Therefore, whether it is possible to modify serogroup B Neisseria meningitidis using specific biomaterials and reduce its virulence is a research direction worth considering. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a method for reducing the toxicity of serogroup B meningococci by endocytizing quantum dots, thus possessing potential for use as a vaccine. To achieve this objective, the present invention provides the following technical solution: A method for preparing quantum dot-modified group B Neisseria meningitidis, the method comprising the following steps: (1) Corn stalks and sunflower stalks were mixed as straws in a weight ratio of 1~1.5:1. The straw mixture, Escherichia coli DH5α cell membrane and urea were placed in water in a weight ratio of 100:100:1 and subjected to high-temperature heating reaction. The reactants were filtered and dialyzed to prepare aminated quantum dots. (2) Aminated quantum dots and group B meningococcal cell membranes were extruded using a liposome extruder at a weight ratio of 8~10:1 and then subjected to ultrasonic centrifugation to obtain cell membrane hybrid aminated quantum dots. (3) The cell membrane hybrid amination quantum dots were co-incubated with group B meningococcal bacteria to obtain quantum dot modified group B meningococcal bacteria.

[0005] Preferably, in step (1), the high-temperature heating is carried out in a high-pressure reactor lined with polytetrafluoroethylene, the reaction temperature is 200°C, and the reaction time is 12 hours.

[0006] Preferably, in step (1), after the reaction is complete, the solution is filtered with ordinary qualitative filter paper and then filtered with a 0.22 μm microporous membrane to obtain a clear quantum dot solution; the filtrate is placed in a dialysis bag with a molecular weight cutoff of 1000 Da and dialyzed in deionized water for 3 days, with the water changed 3 times a day; the dialyzed solution is freeze-dried to obtain amination quantum dots.

[0007] Preferably, in step (2), the polycarbonate filter membranes with decreasing pore sizes are repeatedly extruded; the pore sizes of the polycarbonate filter membranes with decreasing pore sizes are 400nm, 200nm, and 100nm, respectively.

[0008] Preferably, in step (2), the number of extrusions is 30.

[0009] Preferably, in step (2), the temperature is 4°C, the centrifugal force is 100000×g, and the centrifugation time is 1 hour when performing ultrasound.

[0010] Preferably, in step (3), the obtained cell membrane hybrid aminated quantum dots are co-incubated with group B meningococcal bacteria in the logarithmic growth phase for 2 hours; every 10 7 CFU with 10mg of cell membrane hybrid amino-modified quantum dots.

[0011] Preferably, the weight ratio of corn stalks to sunflower stalks is 1:1; the weight ratio of aminated quantum dots to Neisseria meningitidis cell membranes is 10:1.

[0012] A quantum dot-modified group B meningococcal bacteria, wherein the quantum dot-modified group B meningococcal bacteria is prepared by the aforementioned preparation method.

[0013] The aforementioned application of quantum dot-modified group B meningococcal bacteria in vaccine preparation.

[0014] The beneficial effects of this invention are: This invention modifies serogroup B meningococci using specific quantum dots, resulting in a significantly reduced virulence of the modified serogroup B meningococci, which is expected to have applications in vaccines and related fields. Detailed Implementation

[0015] The present invention will be specifically described below through embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above-described invention are still within the scope of protection of the present invention.

[0016] Example 1 1. Preparation of amination quantum dots: (1) Raw materials and reagents: corn stalks (gifted from local farmers, washed and dried in an oven at 60℃), sunflower stalks (gifted from local farmers, washed and dried in an oven at 60℃), Neisseria meningitidis group B cell membrane, Escherichia coli DH5α cell membrane, extraction buffer: 0.1 mol / L Tris-Cl, 1 mmol / L EDTA, 0.5% sodium deoxycholate (pH= 8.6); The cell membranes of Neisseria meningitidis serogroup B and Escherichia coli DH5α were obtained using the following protocol: 1) Culture the bacteria to the logarithmic phase, collect the bacterial culture, and centrifuge to collect the bacterial cell precipitate; 2) Resuspend the bacterial cell precipitate in extraction buffer pre-cooled at 4℃ to obtain a bacterial suspension; immerse the ultrasonic probe in the bacterial suspension, set the ultrasonic power to 200W, and perform intermittent ultrasonication (5 seconds of ultrasonication followed by 5 seconds of intermittent interval), with a total intermittent ultrasonication time of 10 minutes, to achieve the disruption of the bacterial cells; 3) Centrifuge the ruptured bacterial suspension at 4°C and 3000×g for 10 minutes, and transfer the supernatant to a new centrifuge tube; the supernatant contains cell membranes, cytoplasm and other soluble components; 4) Centrifuge the supernatant obtained in step 3) at 4°C and 100,000×g for 1 hour. The supernatant obtained after centrifugation is mainly composed of cytoplasmic proteins, which should be discarded. Collect the precipitate, which is the enriched cell membrane component. 5) Gently resuspend the precipitate with a small amount of pre-cooled PBS, wash it, and then centrifuge it again at 100,000×g at 4°C for 1 hour to remove residual proteins. Discard the supernatant and take the precipitate, which is the cell membrane. Resuspend the final membrane precipitate with PBS and store it.

[0017] (2) Preparation method: Corn stalks and sunflower stalks were prepared in a 1:1 weight ratio, crushed, and mixed to obtain a stalk mixture. 100 parts by weight of the stalk mixture and 100 parts by weight of urea were prepared. One part by weight of E. coli DH5α cell membrane (precipitate) was also prepared. The stalk mixture, E. coli DH5α cell membrane (precipitate), and urea were placed in deionized water to achieve a solute-to-solution weight ratio of 150 mg / 100 mL, and thoroughly mixed. The mixture was then placed in a polytetrafluoroethylene-lined high-pressure reactor, and the reaction temperature was set to 200℃ for 12 hours. After the reaction, the solution was filtered through ordinary qualitative filter paper, followed by filtration through a 0.22 μm microporous membrane to obtain a clear quantum dot solution. The filtrate was placed in a dialysis bag with a molecular weight cutoff of 1000 Da and dialyzed in deionized water for 3 days, changing the water 3 times a day. The dialyzed solution was then freeze-dried to obtain amination-modified quantum dots for later use.

[0018] 2. Preparation of quantum dot-modified group B Neisseria meningitidis (1) Take the obtained aminated quantum dots and Neisseria meningitidis cell membrane (precipitate) in a weight ratio of 10:1, resuspend them in deionized water, and use a liposome extruder to repeatedly extrude them through polycarbonate filter membranes with decreasing pore sizes (400nm, 200nm, 100nm) for a total of 30 times. (2) The squeezed solution was subjected to ultracentrifugation at 100,000 × g for 1 hour at 4°C to obtain cell membrane hybrid amination quantum dots; (3) The obtained cell membrane hybrid amination quantum dots were co-incubated with group B meningococcal bacteria in the logarithmic growth phase for 2 hours to obtain quantum dot-modified group B meningococcal bacteria; in this step, every 10 7 CFU with 10mg of cell membrane hybrid amino-modified quantum dots.

[0019] Example 2 1. Preparation of amination quantum dots: (1) Raw materials and reagents: corn stalks (gifted from local farmers, washed and dried in an oven at 60℃), sunflower stalks (gifted from local farmers, washed and dried in an oven at 60℃), Neisseria meningitidis group B cell membrane, Escherichia coli DH5α cell membrane, extraction buffer: 0.1 mol / L Tris-Cl, 1 mmol / L EDTA, 0.5% sodium deoxycholate (pH= 8.6); The cell membranes of Neisseria meningitidis serogroup B and Escherichia coli DH5α were obtained using the following protocol: 1) Culture the bacteria to the logarithmic phase, collect the bacterial culture, and centrifuge to collect the bacterial cell precipitate; 2) Resuspend the bacterial cell precipitate in extraction buffer pre-cooled at 4℃ to obtain a bacterial suspension; immerse the ultrasonic probe in the bacterial suspension, set the ultrasonic power to 200W, and perform intermittent ultrasonication (5 seconds of ultrasonication followed by 5 seconds of intermittent interval), with a total intermittent ultrasonication time of 10 minutes, to achieve the disruption of the bacterial cells; 3) Centrifuge the ruptured bacterial suspension at 4°C and 3000×g for 10 minutes, and transfer the supernatant to a new centrifuge tube; the supernatant contains cell membranes, cytoplasm and other soluble components; 4) Centrifuge the supernatant obtained in step 3) at 4°C and 100,000×g for 1 hour. The supernatant obtained after centrifugation is mainly composed of cytoplasmic proteins, which should be discarded. Collect the precipitate, which is the enriched cell membrane component. 5) Gently resuspend the precipitate with a small amount of pre-cooled PBS, wash it, and then centrifuge it again at 100,000×g at 4°C for 1 hour to remove residual proteins. Discard the supernatant and take the precipitate, which is the cell membrane. Resuspend the final membrane precipitate with PBS and store it.

[0020] (2) Preparation method: Corn stalks and sunflower stalks were prepared in a weight ratio of 1.5:1, crushed, and mixed to obtain a stalk mixture. 100 parts by weight of the stalk mixture and 100 parts by weight of urea were prepared. One part by weight of E. coli DH5α cell membrane (precipitate) was also prepared. The stalk mixture, E. coli DH5α cell membrane (precipitate), and urea were placed in deionized water to achieve a solute-to-solution weight ratio of 150 mg / 100 mL, and thoroughly mixed. The mixture was then placed in a polytetrafluoroethylene-lined high-pressure reactor, and the reaction temperature was set to 200℃ for 12 hours. After the reaction, the solution was filtered through ordinary qualitative filter paper, followed by filtration through a 0.22 μm microporous membrane to obtain a clear quantum dot solution. The filtrate was placed in a dialysis bag with a molecular weight cutoff of 1000 Da and dialyzed in deionized water for 3 days, changing the water 3 times a day. The dialyzed solution was then freeze-dried to obtain amination-modified quantum dots for later use.

[0021] 2. Preparation of quantum dot-modified group B Neisseria meningitidis (1) Take the obtained aminated quantum dots and Neisseria meningitidis cell membrane (precipitate) in a weight ratio of 8:1, resuspend them in deionized water, and use a liposome extruder to repeatedly extrude them through polycarbonate filter membranes with decreasing pore sizes (400nm, 200nm, 100nm) for a total of 30 times. (2) The squeezed solution was subjected to ultracentrifugation at 100,000 × g for 1 hour at 4°C to obtain cell membrane hybrid amination quantum dots; (3) The obtained cell membrane hybrid amination quantum dots were co-incubated with group B meningococcal bacteria in the logarithmic growth phase for 2 hours to obtain quantum dot-modified group B meningococcal bacteria; in this step, every 10 7 CFU with 10mg of cell membrane hybrid amino-modified quantum dots.

[0022] Comparative Example 1 Compared with Example 1, the difference lies in the fact that the weight ratio of the aminated quantum dots to the group B meningococcal cell membrane is 1:1 when preparing the cell membrane hybrid aminated quantum dots, while the rest is the same as in Example 1.

[0023] The specific plan is as follows: 1. Preparation of amination quantum dots: (1) Raw materials and reagents: corn stalks (gifted from local farmers, washed and dried in an oven at 60℃), sunflower stalks (gifted from local farmers, washed and dried in an oven at 60℃), Neisseria meningitidis group B cell membrane, Escherichia coli DH5α cell membrane, extraction buffer: 0.1 mol / L Tris-Cl, 1 mmol / L EDTA, 0.5% sodium deoxycholate (pH= 8.6); The cell membranes of Neisseria meningitidis serogroup B and Escherichia coli DH5α were obtained using the following protocol: 1) Culture the bacteria to the logarithmic phase, collect the bacterial culture, and centrifuge to collect the bacterial cell precipitate; 2) Resuspend the bacterial cell precipitate in extraction buffer pre-cooled at 4℃ to obtain a bacterial suspension; immerse the ultrasonic probe in the bacterial suspension, set the ultrasonic power to 200W, and perform intermittent ultrasonication (5 seconds of ultrasonication followed by 5 seconds of intermittent interval), with a total intermittent ultrasonication time of 10 minutes, to achieve the disruption of the bacterial cells; 3) Centrifuge the ruptured bacterial suspension at 4°C and 3000×g for 10 minutes, and transfer the supernatant to a new centrifuge tube; the supernatant contains cell membranes, cytoplasm and other soluble components; 4) Centrifuge the supernatant obtained in step 3) at 4°C and 100,000×g for 1 hour. The supernatant obtained after centrifugation is mainly composed of cytoplasmic proteins, which should be discarded. Collect the precipitate, which is the enriched cell membrane component. 5) Gently resuspend the precipitate with a small amount of pre-cooled PBS, wash it, and then centrifuge it again at 100,000×g at 4°C for 1 hour to remove residual proteins. Discard the supernatant and take the precipitate, which is the cell membrane. Resuspend the final membrane precipitate with PBS and store it.

[0024] (2) Preparation method: Corn stalks and sunflower stalks were prepared in a 1:1 weight ratio, crushed, and mixed to obtain a stalk mixture. 100 parts by weight of the stalk mixture and 100 parts by weight of urea were prepared. One part by weight of E. coli DH5α cell membrane (precipitate) was also prepared. The stalk mixture, E. coli DH5α cell membrane (precipitate), and urea were placed in deionized water to achieve a solute-to-solution weight ratio of 150 mg / 100 mL, and thoroughly mixed. The mixture was then placed in a polytetrafluoroethylene-lined high-pressure reactor, and the reaction temperature was set to 200℃ for 12 hours. After the reaction, the solution was filtered through ordinary qualitative filter paper, followed by filtration through a 0.22 μm microporous membrane to obtain a clear quantum dot solution. The filtrate was placed in a dialysis bag with a molecular weight cutoff of 1000 Da and dialyzed in deionized water for 3 days, changing the water 3 times a day. The dialyzed solution was then freeze-dried to obtain amination-modified quantum dots for later use.

[0025] 2. Preparation of quantum dot-modified group B Neisseria meningitidis (1) Take the obtained aminated quantum dots and Neisseria meningitidis cell membrane (precipitate) in a weight ratio of 1:1, resuspend them in deionized water, and use a liposome extruder to repeatedly extrude them through polycarbonate filter membranes with decreasing pore sizes (400nm, 200nm, 100nm) for a total of 30 times. (2) The squeezed solution was subjected to ultracentrifugation at 100,000 × g for 1 hour at 4°C to obtain cell membrane hybrid amination quantum dots; (3) The obtained cell membrane hybrid amination quantum dots were co-incubated with group B meningococcal bacteria in the logarithmic growth phase for 2 hours to obtain quantum dot-modified group B meningococcal bacteria; in this step, every 10 7 CFU with 10mg of cell membrane hybrid amino-modified quantum dots.

[0026] Comparative Example 2 Compared with Example 1, the difference is that E. coli DH5α cell membrane is not added when preparing aminated quantum dots, otherwise it is the same as Example 1.

[0027] The specific plan is as follows: 1. Preparation of amination quantum dots: (1) Raw materials and reagents: corn stalks (gifted from local farmers, washed and dried in an oven at 60℃), sunflower stalks (gifted from local farmers, washed and dried in an oven at 60℃), Neisseria meningitidis cell membranes, extraction buffer: 0.1 mol / L Tris-Cl, 1 mmol / L EDTA, 0.5% sodium deoxycholate (pH= 8.6); The cell membrane of serogroup B meningococcus was obtained using the following protocol: 1) Culture the bacteria to the logarithmic phase, collect the bacterial culture, and centrifuge to collect the bacterial cell precipitate; 2) Resuspend the bacterial cell precipitate in extraction buffer pre-cooled at 4℃ to obtain a bacterial suspension; immerse the ultrasonic probe in the bacterial suspension, set the ultrasonic power to 200W, and perform intermittent ultrasonication (5 seconds of ultrasonication followed by 5 seconds of intermittent interval), with a total intermittent ultrasonication time of 10 minutes, to achieve the disruption of the bacterial cells; 3) Centrifuge the ruptured bacterial suspension at 4°C and 3000×g for 10 minutes, and transfer the supernatant to a new centrifuge tube; the supernatant contains cell membranes, cytoplasm and other soluble components; 4) Centrifuge the supernatant obtained in step 3) at 4°C and 100,000×g for 1 hour. The supernatant obtained after centrifugation is mainly composed of cytoplasmic proteins, which should be discarded. Collect the precipitate, which is the enriched cell membrane component. 5) Gently resuspend the precipitate with a small amount of pre-cooled PBS, wash it, and then centrifuge it again at 100,000×g at 4°C for 1 hour to remove residual proteins. Discard the supernatant and take the precipitate, which is the cell membrane. Resuspend the final membrane precipitate with PBS and store it.

[0028] (2) Preparation method: Corn stalks and sunflower stalks were prepared in a 1:1 weight ratio, crushed, and mixed to obtain a stalk mixture. 100 parts by weight of the stalk mixture and 100 parts by weight of urea were prepared. The stalk mixture and urea were placed in deionized water to achieve a solute-to-solution weight ratio of 150 mg / 100 mL, and thoroughly stirred. The mixture was then placed in a polytetrafluoroethylene-lined high-pressure reactor, and the reaction temperature was set to 200℃ for 12 hours. After the reaction was complete, the solution was filtered through ordinary qualitative filter paper, followed by filtration through a 0.22 μm microporous membrane to obtain a clear quantum dot solution. The filtrate was placed in a dialysis bag with a molecular weight cutoff of 1000 Da and dialyzed in deionized water for 3 days, changing the water 3 times a day. The dialyzed solution was then freeze-dried to obtain amination-modified quantum dots for later use.

[0029] 2. Preparation of quantum dot-modified group B Neisseria meningitidis (1) Take the obtained aminated quantum dots and Neisseria meningitidis cell membrane (precipitate) in a weight ratio of 10:1, resuspend them in deionized water, and use a liposome extruder to repeatedly extrude them through polycarbonate filter membranes with decreasing pore sizes (400nm, 200nm, 100nm) for a total of 30 times. (2) The squeezed solution was subjected to ultracentrifugation at 100,000 × g for 1 hour at 4°C to obtain cell membrane hybrid amination quantum dots; (3) The obtained cell membrane hybrid amination quantum dots were co-incubated with group B meningococcal bacteria in the logarithmic growth phase for 2 hours to obtain quantum dot-modified group B meningococcal bacteria; in this step, every 10 7 CFU with 10mg of cell membrane hybrid amino-modified quantum dots.

[0030] Experimental Example 1 This experiment tested the virulence levels of the bacteria obtained in Example 1, Example 2, Comparative Example 1, and Comparative Example 2. The larvae of the large wax moth were used as the model organism for virulence determination, and unmodified group B Neisseria meningitidis was used as the control group.

[0031] The specific plan is as follows: 1. Streak Neisseria meningitidis group B on chocolate agar and incubate at 37°C with 5% CO2 for 24 hours. Inoculate single colonies into liquid culture medium and incubate at 37°C with shaking until the logarithmic growth phase. Collect the cells by centrifugation, resuspend in sterile PBS, and adjust the bacterial suspension to approximately 1×10⁻⁶. 9 The stock solution concentration was determined by CFU / mL, and then serial dilutions were performed (1×10⁻⁶). 8 CFU / mL, 1×10 7 CFU / mL, 1×10 6 CFU / mL, 1×105 CFU / mL, 1×10 4 (CFU / mL).

[0032] 2. Select 200-300 mg weight of large wax moth larvae and starve them for 24 hours with only moistened filter paper before infection; then divide them into groups according to different implementation examples, comparative examples and control groups, with 10 larvae in each group; 3. Use a cotton swab dipped in 70% ethanol to gently wipe the surface of the larva near the last pair of abdominal prolegs on the left anterior side for disinfection; fix the larva on the palm of your hand or a soft pad, and use a microsyringe to insert the needle at a 30-degree angle under the wiped surface and slowly inject 10 μL of bacterial solution; after injection, gently place the larva in a sterile culture dish and incubate it in a 37°C constant temperature incubator in the dark, observing and recording every 12 hours for at least 72 hours; investigate the median lethal dose.

[0033] 4. The experimental results are shown in Table 1. It can be seen that the bacteria treated in Examples 1 and 2 have lower virulence, and the median lethal dose is three orders of magnitude higher than that of the untreated bacteria, showing a significant virulence reduction effect. However, the virulence reduction effect of the bacteria obtained in Comparative Example 1 is not obvious, and the virulence of the bacteria obtained in Comparative Example 2 is unchanged compared with the control group.

[0034]

[0035] Experiment Example 2 This experiment tested the virulence levels of the bacteria obtained in Example 1, Example 2, Comparative Example 1, and Comparative Example 2. Different concentrations of bacteria were injected intraperitoneally into BALB / c mice to determine their virulence, with unmodified group B Neisseria meningitidis used as the control group.

[0036] The specific plan is as follows: 1. Streak Neisseria meningitidis group B on chocolate agar and incubate at 37°C with 5% CO2 for 24 hours. Inoculate single colonies into liquid culture medium and incubate at 37°C with shaking until the logarithmic growth phase. Collect the cells by centrifugation, resuspend in sterile PBS, and adjust the bacterial suspension to approximately 1×10⁻⁶. 9 The stock solution concentration was determined by CFU / mL, and then serial dilutions were performed (1×10⁻⁶). 8 CFU / mL, 1×10 7 CFU / mL, 1×10 6 CFU / mL, 1×10 5 CFU / mL, 1×10 4 (CFU / mL).

[0037] 2. Six-week-old BALB / c mice were selected and fasted for 12 hours before intraperitoneal injection. They were then divided into groups according to different implementation examples, comparative examples, and control groups, with 10 mice in each group. 3. Inject 100 μL of bacterial solution of different concentrations into the embodiment via intraperitoneal injection. After injection, wait until the bacterial solution does not leak out, then put the mouse back into the cage and observe its behavioral and condition changes. Measure its weight every 12 hours. When its weight drops by more than 20% of its original weight, the mouse is considered dead. Observe for one week, record the number of mice that are considered dead, and calculate the median lethal dose for different embodiments.

[0038] 4. The experimental results are shown in Table 2. It can be seen that the bacteria treated in Examples 1 and 2 have lower virulence, and the median lethal dose is increased by 4 orders of magnitude compared with the untreated bacteria, showing a significant virulence reduction effect. However, the virulence reduction effect of the bacteria obtained in Comparative Example 1 is not obvious, and the virulence of the bacteria obtained in Comparative Example 2 is unchanged compared with the control group.

[0039]

Claims

1. A method for preparing quantum dot-modified group B Neisseria meningitidis, characterized in that, The preparation method includes the following steps: (1) Corn stalks and sunflower stalks were mixed as straws in a weight ratio of 1~1.5:

1. The straw mixture, Escherichia coli DH5α cell membrane and urea were placed in water in a weight ratio of 100:100:1 and subjected to high-temperature heating reaction. The reactants were filtered and dialyzed to prepare aminated quantum dots. (2) Aminated quantum dots and group B meningococcal cell membranes were extruded using a liposome extruder at a weight ratio of 8~10:1 and then subjected to ultrasonic centrifugation to obtain cell membrane hybrid aminated quantum dots. (3) The cell membrane hybrid amination quantum dots were co-incubated with group B meningococcal bacteria to obtain quantum dot modified group B meningococcal bacteria.

2. The method for preparing quantum dot-modified group B Neisseria meningitidis according to claim 1, characterized in that, In step (1), the high-temperature heating is carried out in a high-pressure reactor lined with polytetrafluoroethylene, the reaction temperature is 200°C and the reaction time is 12 hours.

3. The method for preparing quantum dot-modified group B Neisseria meningitidis according to claim 2, characterized in that, In step (1), after the reaction is complete, the solution is filtered with ordinary qualitative filter paper and then filtered with a 0.22 μm microporous membrane to obtain a clear quantum dot solution. The filtrate is placed in a dialysis bag with a molecular weight cutoff of 1000 Da and dialyzed in deionized water for 3 days, with the water changed 3 times a day. The dialyzed solution is freeze-dried to obtain amination quantum dots.

4. The method for preparing quantum dot-modified group B Neisseria meningitidis according to claim 1, characterized in that, In step (2), the polycarbonate filter membranes with decreasing pore sizes are repeatedly extruded in sequence; the pore sizes of the polycarbonate filter membranes with decreasing pore sizes are 400nm, 200nm and 100nm respectively.

5. The method for preparing quantum dot-modified group B Neisseria meningitidis according to claim 4, characterized in that, In step (2), the number of extrusions is 30.

6. The method for preparing quantum dot-modified group B Neisseria meningitidis according to claim 1, characterized in that, In step (2), the temperature is 4℃, the centrifugal force is 100000×g, and the centrifugation time is 1 hour when performing ultrasound.

7. The method for preparing quantum dot-modified group B Neisseria meningitidis according to claim 1, characterized in that, In step (3), the obtained cell membrane hybrid aminated quantum dots were co-incubated with group B meningococcal bacteria in the logarithmic growth phase for 2 hours; every 10 7 CFU with 10mg of cell membrane hybrid amino-modified quantum dots.

8. The method for preparing quantum dot-modified group B Neisseria meningitidis according to claim 1, characterized in that, The weight ratio of corn stalks to sunflower stalks was 1:1; the weight ratio of aminated quantum dots to Neisseria meningitidis cell membranes was 10:

1.

9. A quantum dot-modified group B Neisseria meningitidis, characterized in that, The quantum dot-modified group B meningococcal bacteria is prepared by the preparation method according to any one of claims 1 to 8.

10. The application of the quantum dot-modified group B meningococcal bacteria as described in claim 9 in the preparation of vaccines.

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