Antibacterial imidazolyl carbonized polymer dot as well as preparation method and application thereof

Abstract

The invention discloses a preparation method of antibacterial imidazolyl carbonized polymer dots, which comprises the following steps: S1, dissolving a carbon source and an imidazolyl ionic liquid in a solvent, and uniformly mixing the components to obtain a mixed solution; s2, putting the mixed solution into a reaction kettle, and heating; and S3, after the reaction is finished, cooling and taking out the solution, and freeze-drying to obtain the antibacterial imidazolyl carbonized polymer dots. According to the preparation method, a polymer is used as a carbon source, imidazolyl ionic liquid is used as a passivating agent, the imidazole functionalized carbonized polymer point with a good antibacterial effect is prepared by adopting a one-step solvothermal method and serves as the novel antibacterial carbon point, and the novel antibacterial carbon point shows efficient antibacterial performance on staphylococcus aureus and escherichia coli.

Description

Technical Field

[0001] The present invention relates to the field of medical technology, and in particular to an antibacterial imidazole carbonized polymer dot and a preparation method and application thereof. Background Art

[0002] Bacterial infection refers to local or systemic infection caused by pathogenic bacteria or conditionally pathogenic bacteria invading the human blood circulation system, growing and multiplying, and producing toxins and other metabolites. The discovery of antibiotics once brought hope to mankind, but due to the widespread use of antibiotics, many pathogens have become resistant. In the past twenty years, the number of pathogens resistant to first-line clinical antimicrobial drugs has doubled. In addition to first-line drugs, resistance of pathogens to second-line and third-line clinical drugs is also becoming increasingly common. The simultaneous use of different antibiotics has exacerbated bacteria's multidrug resistance to antibiotics, and bacterial infections have once again become one of the biggest challenges facing global human health.

[0003] In recent years, carbon-based nanomaterials have been widely used in medical and life science research, such as drug delivery, bioimaging, photothermal therapy, gene delivery and tissue engineering. In particular, nanomaterials based on carbon dots have attracted widespread attention due to their low toxicity and good biocompatibility. A key advantage of carbon dots (CDs) is that they contain abundant surface active groups, which allows CDs to chemically modify different molecules or functional groups for use in biomarkers, biosensors, tissue imaging and other fields. As an alternative to antibiotics, carbon dots are a promising material with simple preparation methods, low cost, easy surface functionalization, excellent antibacterial activity and unique antibacterial mechanism. Summary of the invention

[0004] The main purpose of the present invention is to propose a method for preparing antibacterial imidazole-based carbonized polymer dots, which adopts a one-step solvent thermal method to prepare imidazole-based carbonized polymer dots with good antibacterial effect, and have high antibacterial properties against Staphylococcus aureus and Escherichia coli.

[0005] To achieve the above object, the present invention provides a method for preparing antibacterial imidazole-based carbonized polymer dots, comprising the following steps:

[0006] S1, dissolving the carbon source and the imidazolyl ionic liquid in a solvent, and mixing the components evenly to obtain a mixed solution;

[0007] S2, placing the mixed solution in a reaction kettle and heating;

[0008] S3. After the reaction is completed, the solution is cooled and taken out, and the antibacterial imidazole carbonized polymer dots are obtained after freeze-drying.

[0009] The present invention uses polymer as carbon source and imidazolyl ionic liquid as passivating agent, and adopts a one-step solvothermal method to prepare imidazole functionalized carbonized polymer dots with good antibacterial effect as new antibacterial carbon dots, which show high antibacterial performance against Staphylococcus aureus and Escherichia coli. The preparation process is simple and efficient, and the antibacterial performance is excellent, which provides a new idea for expanding the research and development of safe and low-toxic carbon nanomaterial antibacterial agents.

[0010] Preferably, the carbon source is 0.1 to 15.0 g.

[0011] Preferably, the imidazolyl ionic liquid is 0.1 to 15.0 g.

[0012] Preferably, the solvent is 5.0 to 50.0 mL.

[0013] Preferably, the mass ratio of the carbon source to the imidazolyl ionic liquid is 10:1-5.

[0014] By adjusting the ratio of carbon source and imidazolyl ionic liquid, the yield of carbon dots can be further improved and better fluorescence effect can be obtained. While having good antibacterial efficacy, it can also achieve marked identification of bacterial infection.

[0015] Preferably, the carbon source comprises one or more of polyacrylic acid, sodium polyacrylate, polyvinyl alcohol, polyethyleneimine, hyaluronic acid and alginic acid.

[0016] Preferably, the imidazolyl ionic liquid includes one or more of 1-propylamino-3-methylimidazolium bromide, 1-butyl-3-methylimidazolium proline, 1-propyl-3-methylimidazolium threonine, 1-propyl-3-methylimidazolium serine, 1-hexyl-3-methylimidazolium tryptophanate, and 1-butyl-3-methylimidazolium alanine.

[0017] Preferably, the solvent is any one of methanol and water.

[0018] Preferably, the heating temperature in step S2 is 140-200° C., and the heating time is 4-10 hours.

[0019] In addition, the present invention also provides an antibacterial imidazole-based carbonized polymer dot prepared by the above preparation method.

[0020] The present invention also provides an application of the antibacterial imidazole-based carbonized polymer dots in the fields of antibacterial diagnosis and treatment and bacterial infection identification.

[0021] Compared with the prior art, the imidazole-functionalized carbonized polymer dots prepared by the technical solution described in the present invention can effectively kill drug-resistant bacteria, especially have high antibacterial properties against Staphylococcus aureus and Escherichia coli. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying any creative work.

[0023] Figure 1 , the antibacterial activity of the imidazole carbonized polymer dots prepared in Examples 1 to 6 and Comparative Examples 1 and 2 against Escherichia coli and Staphylococcus aureus;

[0024] Figure 2 , the antibacterial activity of the imidazole carbonized polymer dots prepared in Example 7 against Escherichia coli and Staphylococcus aureus;

[0025] Figure 3 , Example 7-3 Cell imaging diagram.

[0026] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in this field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0028] A method for preparing antibacterial imidazole-based carbonized polymer dots comprises the following steps:

[0029] S1, dissolving 0.1-15.0 g of carbon source and 0.1-15.0 g of imidazole-based ionic liquid in 5.0-50.0 mL of solvent, and mixing the components evenly to obtain a mixed solution;

[0030] S2, placing the mixed solution in a reaction kettle, and reacting at 140-200° C. for 4-10 hours;

[0031] S3. After the reaction is completed, the solution is cooled and taken out, and the antibacterial imidazole carbonized polymer dots are obtained after freeze-drying.

[0032] Preferably, the carbon source includes one or more of polyacrylic acid, sodium polyacrylate, polyvinyl alcohol, polyethyleneimine, hyaluronic acid and alginic acid. By selecting a polymer as a carbon source, carbon dots are formed on the long chain, so that more carbon dots are formed and the antibacterial effect is higher.

[0033] Preferably, the imidazolyl ionic liquid includes one or more of 1-propylamino-3-methylimidazolyl bromide, 1-butyl-3-methylimidazolyl proline, 1-propyl-3-methylimidazolyl threonate, 1-propyl-3-methylimidazolyl serine, 1-hexyl-3-methylimidazolyl tryptophanate, and 1-butyl-3-methylimidazolyl alanate. The imidazolyl ionic liquid is selected as a passivating agent, and the prepared carbon dots have residual imidazole groups, and the antibacterial performance of the composite carbon dots can further enhance the overall antibacterial effect.

[0034] Preferably, the solvent includes any one of methanol and water.

[0035] Preferably, the mass ratio of the carbon source to the imidazolyl ionic liquid is 10:1-5.

[0036] The present invention is further described below by listing examples. It should be understood that the following examples are only used to illustrate the present invention, rather than to limit the present invention.

[0037] Examples 1 to 6

[0038] A method for preparing antibacterial imidazole-based carbonized polymer dots comprises the following steps:

[0039] S1. According to the raw material components shown in Table 1, weigh a carbon source and an imidazole-based ionic liquid, dissolve them in a solvent, and ultrasonically dissolve and mix them to obtain a mixed solution;

[0040] S2, adding the mixed solution in step S1 into a hydrothermal reactor and reacting at 180°C for 5h;

[0041] S3. After the reaction is completed, the mixture is naturally cooled to room temperature, the solution is taken out, filtered through a membrane, dialyzed, and freeze-dried to obtain the imidazole-based carbonized polymer dots.

[0042] Comparative Example 1

[0043] A method for preparing carbonized polymer dots comprises the following steps:

[0044] S1. Weigh 1.0 g of polyacrylic acid and 0.25 g of glycine, dissolve them in 15.0 mL of deionized water, and mix them by ultrasonic dissolution to obtain a mixed solution;

[0045] S2, adding the mixed solution in step S1 into a hydrothermal reactor and reacting at 180°C for 5h;

[0046] S3. After the reaction is completed, the solution is naturally cooled to room temperature, and the solution is taken out, passed through a membrane, dialyzed, and freeze-dried to obtain the antibacterial carbonized polymer dots.

[0047] Comparative Example 2

[0048] A method for preparing imidazole carbon dots comprises the following steps:

[0049] S1. Weigh 1.0 g of citric acid and 0.25 g of 1-butyl-3-methylimidazolium proline salt, dissolve them in 15.0 mL of methanol, and mix them by ultrasonic dissolution to obtain a mixed solution;

[0050] S2, adding the mixed solution in step S1 into a hydrothermal reactor and reacting at 180°C for 5h;

[0051] S3. After the reaction is completed, the mixture is naturally cooled to room temperature, the solution is taken out, filtered through a membrane, dialyzed, and freeze-dried to obtain the imidazole-based carbonized polymer dots.

[0052] Table 1

[0053]

[0054] The materials obtained in Examples 1 to 6 and Comparative Examples 1 and 2 were tested for their in vitro antibacterial properties:

[0055] The antibacterial properties of the materials prepared in Examples 1 to 6 and Comparative Examples 1 and 2 were evaluated using Gram-positive bacteria Staphylococcus aureus and Gram-negative bacteria Escherichia coli. The PBS group was used as the control group.

[0056] On the clean bench, pour LB medium (sterilized at 121℃ for 20min) onto the medium plate and wait for it to solidify. Add 5mL of bacterial solution containing carbon dots to the solidified medium plate, where the concentration of carbon dots is 1mg / mL and the concentration of bacteria is 1×10 6 CFU / mL, and then quickly and evenly spread it with a spreader, and inverted culture in a 37°C incubator for 12 hours. The plate counting method was used to quantitatively analyze the antibacterial effect. Each group of experiments was performed in parallel 3 times. The average colony count of the 3 parallel experiments in each group of experiments was used as the final colony count of the group of experiments. The calculation formula for the antibacterial rate is as follows:

[0057] Antibacterial rate (%) = (N 总菌落数 -N 活菌数 ) / N 总菌落数 ×100%

[0058] Test results such as Figure 1As shown. It shows that the imidazole-based carbonized polymer dots prepared in this scheme have good bactericidal effects on Staphylococcus aureus and Escherichia coli, and can effectively reduce the development of bacterial resistance. In Comparative Example 1, no imidazole-based ionic liquid was added, and the prepared carbon dots did not contain imidazole groups, and the antibacterial effect was poor. In Comparative Example 2, no polymer was used as a carbon source. Compared with the present scheme of preparing carbon dots on long chains, it does not have antibacterial advantages and has lower antibacterial efficacy.

[0059] Example 7

[0060] Example 7 adopts the same preparation method and parameters as Example 5, except that the mass ratio of the carbon source and the imidazolyl ionic liquid is adjusted, as shown in the following table:

[0061] Mass ratio of carbon source and imidazolyl ionic liquid Example 7-1 10:1 Example 7-2 10:2 Example 7-3 10:3 Example 7-4 10:4 Example 7-5 10:5 Example 7-6 15:1 Example 7-7 10:6

[0062] The antibacterial properties of the antibacterial imidazole carbonized polymer dots prepared in Example 7 were tested using the in vitro antibacterial properties test method. The test results are as follows: Figure 2 As shown. The imidazole-based carbonized polymer dots of Example 7 have bactericidal effects on Staphylococcus aureus and Escherichia coli. In particular, the imidazole-based carbonized polymer dots prepared in Examples 7-1 to 7-5 have the best bactericidal effects on Staphylococcus aureus and Escherichia coli; among them, the antibacterial rates of the imidazole-based carbonized polymer dots of Examples 7-6 and 7-7 on Staphylococcus aureus and Escherichia coli are slightly reduced. It can be seen that when the mass ratio of the carbon source to the imidazole-based ionic liquid is in the range of 10:1 to 5, the obtained imidazole-based carbonized polymer dots have the best antibacterial effect.

[0063] The carbon dot quantum yield and fluorescence effect of the imidazole carbonized polymer dots prepared in Example 7 were detected by the following method:

[0064] Calculation of fluorescence quantum yield (QY) The calculation formula of QY is as follows:

[0065]

[0066] Wherein the subscripts ST and X represent the standard quinine sulfate and the test sample, respectively, φ represents the fluorescence quantum yield, Grad represents the ratio of the integral area of ​​the fluorescence emission spectrum to the absorbance, and η represents the refractive index of the solvent. In order to reduce the influence of reabsorption, the absorbance of the 10 mm fluorescence cuvette at the excitation wavelength of the sample shall not exceed 0.1.

[0067] Cell imaging tests were performed as follows:

[0068] First, HCT-116 cells were thawed and incubated. Then, the cells were diluted into a suspension using RPMI-1640 medium (containing 10% fetal bovine serum and 1% penicillin-streptomycin), with a cell density of approximately 1×10 5 / mL. Take a 12-well plate and add 2mL of cell suspension to each well. Shake horizontally to evenly disperse the cells in each well. Add 2mL of pre-sterilized PBS solution to the wells on the outer circle of the well plate to prevent contamination. Place the well plate with cells in the incubator and continue incubation for 24 hours. Remove the original culture medium in the well and add 2mL of new culture medium containing 1.0mg / mL carbon dots to each well and continue incubation for 48 hours. Take out the well plate and remove the mixed solution in the well. Test using a fluorescent inverted microscope.

[0069] The results of detecting the fluorescence quantum yield are as follows:

[0070]

[0071] It can be seen that when the mass ratio of the carbon source to the imidazolyl ionic liquid is in the range of 10:1 to 5, the quantum yield of the carbon dots of the imidazolyl carbonized polymer dots is relatively high, reaching more than 60.4%. While having good antibacterial properties, it can be used for fluorescent labeling and has a wider range of applications. Figure 3 As shown, images of cells labeled using Example 7-3 can be seen.

[0072] In summary, the present invention uses polymer as carbon source and imidazole-based ionic liquid as passivating agent, and uses a one-step solvothermal method to prepare imidazole-based carbonized polymer dots with good antibacterial effect as novel antibacterial carbon dots. The carbon dots are compounded with residual imidazole groups to significantly improve the antibacterial efficacy. Furthermore, by optimizing and limiting the ratio of the raw materials, the prepared imidazole-based carbonized polymer dots not only have efficient antibacterial properties, but also have a higher carbon dot quantum yield and better fluorescence effect, which can realize bacterial infection marker identification.

[0073] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for preparing antibacterial imidazole carbonized polymer dots, characterized in that: The steps include: S1, dissolving the carbon source and the imidazolyl ionic liquid in a solvent, and mixing the components evenly to obtain a mixed solution; S2, placing the mixed solution in a reaction kettle and heating; S3. After the reaction is completed, the solution is cooled and taken out, and the antibacterial imidazole carbonized polymer dots are obtained after freeze-drying.

2. The method for preparing the antibacterial imidazole-based carbonized polymer dots according to claim 1, wherein: The carbon source is 0.1 to 15.0 g.

3. The method for preparing the antibacterial imidazole-based carbonized polymer dots according to claim 1, wherein: The imidazolyl ionic liquid is 0.1 to 15.0 g.

4. The method for preparing the antibacterial imidazole carbonized polymer dots according to claim 1, wherein: The solvent is 5.0 to 50.0 mL.

5. The method for preparing the antibacterial imidazole carbonized polymer dots according to claim 1, wherein: The mass ratio of the carbon source to the imidazolyl ionic liquid is 10:1-5.

6. The method for preparing the antibacterial imidazole carbonized polymer dots according to claim 1, wherein: The carbon source includes one or more of polyacrylic acid, sodium polyacrylate, polyvinyl alcohol, polyoxyethyleneimine, hyaluronic acid and alginic acid.

7. The method for preparing the antibacterial imidazole carbonized polymer dots according to claim 1, wherein: The imidazolyl ionic liquid includes one or more of 1-propylamino-3-methylimidazolium bromide, 1-butyl-3-methylimidazolium proline, 1-propyl-3-methylimidazolium threonine, 1-propyl-3-methylimidazolium serine, 1-hexyl-3-methylimidazolium tryptophan, and 1-butyl-3-methylimidazolium alanine.

8. The method for preparing the antibacterial imidazole-based carbonized polymer dots according to claim 1, wherein: The solvent is any one of methanol and water.

9. An antibacterial imidazole carbonized polymer dot, characterized in that: The antibacterial imidazole carbonized polymer dots are prepared by the preparation method of any one of claims 1 to 8.

10. An application of the antibacterial imidazole-based carbonized polymer dots as claimed in claim 9 in the field of antibacterial diagnosis and treatment and bacterial infection identification.

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