Preparation method of quantum dot nanospheres, quantum dot nanospheres and applications

Abstract

The present invention discloses a preparation method, quantum dot nanospheres, and their applications, relating to the field of quantum dot technology. The preparation method comprises: mixing hydrophobic quantum dots, an organic non-coordinating solvent, and a first emulsifier solution to obtain a quantum dot micelle dispersion; mixing a monomer, a ligand, and a second emulsifier solution to obtain a monomer droplet dispersion; and polymerizing the quantum dot micelle dispersion and the monomer droplet dispersion in the presence of an initiator. By adding a ligand to the monomer and then polymerizing it with the quantum dots, the introduced ligand achieves a dynamic equilibrium of ligands on the quantum dot surface, maintaining a high PLQY of the quantum dots and thereby achieving the preparation of high PLQY quantum dot nanospheres.

Description

Technical Field

[0001] The present invention relates to the field of quantum dot technology, and in particular to a preparation method of quantum dot nanospheres, quantum dot nanospheres and applications. Background Art

[0002] Quantum dots offer the advantages of tunable fluorescence emission wavelength, high photoluminescence quantum yield (PLQY), and excellent fluorescence stability, making them highly favored for the quantitative detection of biomarkers such as proteins, nucleic acids, and cells. However, quantum dots have a small particle size, a large specific surface area, and a rich surface atom population. Their surface ligands also affect their fluorescence properties. During use, environmental factors such as water and oxygen can cause surface structural changes, resulting in a decrease in PLQY and limiting their application.

[0003] Multiple quantum dots are loaded into a nanosphere to form quantum dot fluorescent nanospheres, which can exhibit higher fluorescence intensity than a single fluorescent material. In addition to providing a protective shell, the nanosphere matrix can also reduce the biotoxicity and nonspecific adsorption of the fluorescent material, and provide groups that can be coupled with antibodies. Quantum dots are embedded in the process of preparing nanospheres through copolymerization with monomers. Common methods include suspension polymerization and emulsion polymerization. These methods can ensure that quantum dots do not leak in the use environment. However, the continuous phase of these methods is water, and the ligands of the quantum dots will dissociate and fall off in the aqueous solution, resulting in defects on the surface of the quantum dots and a decrease in PLQY, which affects their application in quantitative detection.

[0004] Therefore, how to maintain the high PLQY of quantum dots when preparing quantum dot nanospheres is an urgent problem to be solved.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] The purpose of the present invention is to provide a preparation method of quantum dot nanospheres and quantum dot nanospheres, aiming to prepare quantum dot nanospheres with high PLQY.

[0007] Another object of the present invention is to provide an application of the above quantum dot nanospheres in quantitative detection.

[0008] The present invention is achieved in that:

[0009] In a first aspect, the present invention provides a method for preparing quantum dot nanospheres, comprising:

[0010] mixing hydrophobic quantum dots, an organic non-coordinating solvent, and a first emulsifier solution to obtain a quantum dot micelle dispersion;

[0011] Mixing the monomer, the ligand, and the second emulsifier solution to obtain a monomer droplet dispersion;

[0012] The quantum dot micelle dispersion and the monomer droplet dispersion are polymerized in the presence of an initiator.

[0013] In an optional embodiment of the present invention, the preparation process of the quantum dot micelle dispersion includes: mixing hydrophobic quantum dots and an organic non-coordinating solvent to obtain a first oil phase mixture, and mixing the first oil phase mixture with a first emulsifier solution.

[0014] In an optional embodiment of the present invention, the mass of the hydrophobic quantum dots per milliliter of the organic non-coordinating solvent is 0.4 g to 2.3 g;

[0015] Preferably, the hydrophobic quantum dots are selected from at least one of group II-VI quantum dots, group II-V quantum dots, group III-V quantum dots, group IV-VI quantum dots, group I-VI quantum dots, group I-III-VI quantum dots, and group IV quantum dots;

[0016] Preferably, the organic non-coordinating solvent is selected from at least one of alkanes and their derivatives, alkenes and their derivatives, cycloalkanes and their derivatives, and benzene and its derivatives;

[0017] More preferably, the organic non-coordinating solvent is at least one selected from hexane or its isomers, heptane or its isomers, octane or its isomers, heptene or its isomers, octene or its isomers, benzene or its isomers, toluene or its isomers, chloroform or its isomers and tetrachloroethylene or its isomers.

[0018] In an optional embodiment of the present invention, the first emulsifier solution is an aqueous solution formed by an amphiphilic compound with a concentration of 1 mg / L-3 mg / L;

[0019] Preferably, the volume ratio of the first oil phase mixture to the first emulsifier solution is 0.5-2:100;

[0020] Preferably, the amphiphilic compound used to prepare the first emulsifier solution is an anionic surfactant.

[0021] In an optional embodiment of the present invention, the preparation process of the monomer droplet dispersion includes: mixing the monomer and the ligand to obtain a second oil phase mixture, and mixing the second oil phase mixture with a second emulsifier solution.

[0022] In an optional embodiment of the present invention, the monomer is a vinyl monomer or a derivative thereof, the ligand is a compound capable of passivating surface defects of quantum dots, and the mass ratio of the monomer to the ligand is 180-220:1;

[0023] Preferably, the monomer is selected from at least one of styrene, divinylbenzene, chlorostyrene, methyl methacrylate, ethyl methacrylate, propyl acrylate and butyl acrylate;

[0024] Preferably, the ligand is selected from at least one of saturated fatty acids, saturated fatty amines, unsaturated fatty acids, unsaturated fatty amines, organic phosphines and thiols.

[0025] In an optional embodiment of the present invention, the second emulsifier solution is an aqueous solution formed by an amphiphilic compound with a concentration of 0.5 mg / L-2 mg / L;

[0026] Preferably, the volume of the second emulsifier solution per gram of the second oil phase mixture is 2 mL to 3 mL;

[0027] Preferably, the amphiphilic compound used to prepare the second emulsifier solution is an anionic surfactant.

[0028] In an optional embodiment of the present invention, the quantum dot micelle dispersion is mixed with the monomer droplet dispersion and the initiator aqueous solution, and the temperature is raised to 60° C.-80° C. for polymerization;

[0029] Preferably, the mass ratio of the quantum dot micelle dispersion to the monomer droplet dispersion is 100:60-80, and the mass ratio of the initiator used to the monomer is 0.05-0.2:10000;

[0030] Preferably, the initiator is selected from at least one of potassium persulfate, azobisisobutylamidine hydrochloride, azobisisobutylimidazoline hydrochloride, azobiscyanovaleric acid and azobisisopropylimidazoline;

[0031] Preferably, the concentration of the initiator aqueous solution is 5 mg / L-15 mg / L;

[0032] Preferably, the polymerization time is 20h-30h;

[0033] Preferably, filtration and concentration are carried out after the polymerization is completed.

[0034] In a second aspect, the present invention further provides a quantum dot nanosphere prepared by the preparation method in any of the above embodiments.

[0035] In a third aspect, the present invention further provides the use of the quantum dot nanospheres in the above embodiment in quantitative detection.

[0036] The present invention has the following beneficial effects: by adding ligands to monomers and then polymerizing with quantum dots, the dynamic balance of ligands on the surface of quantum dots is achieved through the introduced ligands, the high PLQY of the quantum dots is maintained, and the preparation of high PLQY quantum dot nanospheres is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0038] Figure 1 The fluorescence intensity test results of the quantum dot nanospheres obtained in Example 1 and Comparative Example 1 are shown;

[0039] Figure 2 This is the morphology of the product prepared in Example 7. DETAILED DESCRIPTION

[0040] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, all are conventional products that can be purchased commercially.

[0041] An embodiment of the present invention provides a method for preparing quantum dot nanospheres, comprising:

[0042] S1. Preparation of quantum dot micelle dispersion

[0043] The hydrophobic quantum dots, the organic non-coordinating solvent and the first emulsifier solution are mixed to obtain a quantum dot micelle dispersion for later use.

[0044] In some embodiments, the preparation process of the quantum dot micelle dispersion includes: mixing hydrophobic quantum dots and an organic non-coordinating solvent to obtain a first oil phase mixture, mixing the first oil phase mixture with a first emulsifier solution, and controlling the mixing steps to obtain a uniform dispersion.

[0045] In some embodiments, the hydrophobic quantum dots are selected from at least one of group II-VI quantum dots, group II-V quantum dots, group III-V quantum dots, group IV-VI quantum dots, group I-VI quantum dots, group I-III-VI quantum dots, and group IV quantum dots, and may be any one or more of the above, such as group II-VI Zn(S,Se), Cd(S,Se,Te), group II-V Cd3(P,As)2, group III-V In(P,As), group IV-VI Pb(S,Se), group I-VI Ag2(S,Se), group I-III-VI CuIn(S,Se)2, AgIn(S,Se)2, and group IV (C, Si, Ge).

[0046] In some embodiments, the organic non-coordinating solvent is selected from at least one of alkanes and their derivatives, alkenes and their derivatives, cycloalkanes and their derivatives, and benzene and its derivatives, and may be any one or more of the above. Preferably, the organic non-coordinating solvent is selected from at least one of hexane, heptane, octane, heptene, octene, benzene, toluene, chloroform, and tetrachloroethylene, and may be any one or more of the above, or may be isomers of the above.

[0047] In some embodiments, the mass of the hydrophobic quantum dots per milliliter of organic non-coordinating solvent is 0.4 g-2.3 g, such as 0.4 g, 0.5 g, 1.0 g, 1.5 g, 2.0 g, 2.3 g, etc. In actual operation, the ratio of hydrophobic quantum dots to organic non-coordinating solvent can be controlled to 3 g / 7 mL-7 g / 3 mL (m / V).

[0048] In some embodiments, the first emulsifier solution is an aqueous solution of an amphiphilic compound, and the concentration is 1 mg / L-3 mg / L, such as 1 mg / L, 2 mg / L, 3 mg / L, etc. The volume ratio of the first oil phase mixture to the first emulsifier solution is 0.5-2:100, such as 0.5:100, 1.0:100, 1.5:100, 2.0:100, etc.

[0049] In some embodiments, the amphiphilic compound used to prepare the first emulsifier solution is an anionic surfactant, such as sodium dodecylbenzenesulfonate.

[0050] S2. Preparation of monomer droplet dispersion

[0051] The monomer, ligand and second emulsifier solution are mixed to obtain a monomer droplet dispersion for later use.

[0052] In some embodiments, the preparation process of the monomer droplet dispersion includes: mixing the monomer and the ligand to obtain a second oil phase mixture, mixing the second oil phase mixture with a second emulsifier solution, and controlling the mixing steps to obtain a uniform dispersion.

[0053] In some embodiments, the monomer is a vinyl monomer or a derivative thereof, and the ligand is a compound capable of passivating surface defects in the quantum dots. By introducing a ligand compound capable of passivating surface defects in the quantum dots, a dynamic equilibrium of ligands on the quantum dot surface can be achieved, maintaining a high PLQY of the quantum dots and enabling the preparation of high-PLQY quantum dot nanospheres. The mass ratio of monomer to ligand is 180-220:1, such as 180:1, 190:1, 200:1, 210:1, 220:1, etc.

[0054] Furthermore, the monomer is selected from at least one of styrene, divinylbenzene, chlorostyrene, methyl methacrylate, ethyl methacrylate, propyl acrylate and butyl acrylate, and may be any one or more of the above; the ligand is selected from at least one of saturated fatty acids, saturated fatty amines, unsaturated fatty acids, unsaturated fatty amines, organic phosphines and thiols, and may be any one or more of the above.

[0055] In some embodiments, the second emulsifier solution is an aqueous solution of an amphiphilic compound having a concentration of 0.5 mg / L-2 mg / L; the volume of the second emulsifier solution per gram of the second oil phase mixture is 2 mL-3 mL. The amount of emulsifier is controlled to ensure sufficient reaction. Specifically, the concentration of the second emulsifier solution is 0.5 mg / L, 1.0 mg / L, 1.5 mg / L, 2.0 mg / L, etc., and the volume of the second emulsifier solution per gram of the second oil phase mixture is 2 mL, 2.5 mL, 3.0 mL, etc.

[0056] Furthermore, the amphiphilic compound used to prepare the second emulsifier solution is an anionic surfactant, such as sodium dodecylbenzenesulfonate.

[0057] S3, aggregation

[0058] The quantum dot micelle dispersion and the monomer droplet dispersion are polymerized in the presence of an initiator to obtain quantum dot nanospheres.

[0059] In some embodiments, a quantum dot micelle dispersion is mixed with a monomer droplet dispersion and an initiator aqueous solution, and the temperature is raised to 60° C. to 80° C. for polymerization for 20 to 30 hours. Specifically, the polymerization temperature can be 60° C., 70° C., 80° C., etc., and the polymerization time can be 20 hours, 24 hours, 28 hours, 30 hours, etc.

[0060] In some embodiments, the mass ratio of the quantum dot micelle dispersion to the monomer droplet dispersion is 100:60-80, the mass ratio of the initiator to the monomer is 0.05-0.2:10,000, and the concentration of the initiator aqueous solution is 5 mg / L-15 mg / L. By controlling the amount of initiator, quantum dots, and monomers, the reaction can be fully carried out to produce quantum dot nanospheres with a high PLQY.

[0061] Specifically, the mass ratio of the quantum dot micelle dispersion and the monomer droplet dispersion can be 100:60, 100:70, 100:80, etc., the mass ratio of the initiator used to the monomer can be 0.05:10000, 0.10:10000, 0.15:10000, 0.20:10000, etc., and the concentration of the initiator aqueous solution can be 5 mg / L, 10 mg / L, 15 mg / L, etc.

[0062] It should be noted that trace amounts of ligands cannot maintain the PLQY of quantum dots, while excessive addition of ligands will affect the occurrence of polymerization reactions, making it difficult to form quantum dot nanospheres; or affect the solubility of quantum dots in organic solvents, making it difficult to form quantum dot micelles, and forming a large number of agglomerates; it may also destroy the chemical equilibrium between the surface atoms of the quantum dots and the ligands, causing the quantum dot surface to be decomposed, forming more surface defects, and obtaining quantum dot nanospheres with lower PLQY.

[0063] Furthermore, the initiator refers to a compound that can decompose to generate free radicals, without limitation, and can be at least one of potassium persulfate, azobisisobutylamidine hydrochloride, azobisisobutylimidazoline hydrochloride, azobiscyanovaleric acid and azobisisopropylimidazoline, or any one or more of the above.

[0064] In some embodiments, after the polymerization is completed, filtration and concentration are performed to obtain quantum dot fluorescent nanospheres. The filtration method is not limited and can be suction filtration.

[0065] The present invention also provides a quantum dot nanosphere prepared by the above-mentioned preparation method, which has the advantage of high PLQY. The application of the quantum dot nanosphere in quantitative detection has the advantage of high detection accuracy.

[0066] The features and performance of the present invention are further described in detail below with reference to the embodiments.

[0067] Example 1

[0068] This embodiment provides a method for preparing quantum dot nanospheres, comprising:

[0069] (1) 7 g of quantum dots (ZnCdSe) were dispersed in 3 mL of octane to obtain an oil phase mixture A1; sodium dodecyl sulfate was dissolved in water to obtain a sodium dodecyl sulfate aqueous solution A2 with a concentration of 2 mg / L.

[0070] (2) 1 mL of the oil phase mixture A1 was dispersed in 100 mL of the sodium dodecyl sulfate aqueous solution A2 to form a quantum dot micelle dispersion A3.

[0071] (3) Take 20 g of styrene and add 0.1 g of oleic acid to form an oil phase mixture B1; dissolve sodium dodecyl sulfate in water to obtain a sodium dodecyl sulfate aqueous solution B2 with a concentration of 1 mg / L.

[0072] (4) The oil phase mixture B1 obtained in step (3) was dispersed in 50 mL of sodium dodecylsulfonate aqueous solution B2 to form a monomer dispersion B3.

[0073] (5) A3 obtained in step (2) and B3 obtained in step (4) were mixed, 20 mL of potassium persulfate aqueous solution (10 mg / L) was added, and the temperature was raised to 70° C. for polymerization for 24 h.

[0074] (6) Filtration and concentration are performed to obtain the quantum dot fluorescent nanospheres, and the PLQY is tested to be 99.8%.

[0075] Example 2

[0076] This embodiment provides a method for preparing quantum dot nanospheres, comprising:

[0077] (1) 7 g of quantum dots (ZnCdSe) were dispersed in 3 mL of hexane to obtain an oil phase mixture A1; sodium dodecyl sulfate was dissolved in water to obtain a sodium dodecyl sulfate aqueous solution A2 with a concentration of 1 mg / L.

[0078] (2) 2 mL of the oil phase mixture A1 was dispersed in 100 mL of the sodium dodecyl sulfate aqueous solution A2 to form a quantum dot micelle dispersion A3.

[0079] (3) Take 18 g of divinylbenzene and add 0.1 g of oleic acid to form an oil phase mixture B1; dissolve sodium dodecyl sulfate in water to obtain a sodium dodecyl sulfate aqueous solution B2 with a concentration of 0.5 mg / L.

[0080] (4) The oil phase mixture B1 obtained in step (3) was dispersed in 55 mL of sodium dodecylsulfonate aqueous solution B2 to form a monomer dispersion B3.

[0081] (5) A3 obtained in step (2) and B3 obtained in step (4) were mixed, 18 mL of potassium persulfate aqueous solution (5 mg / L) was added, and the temperature was raised to 60° C. for polymerization for 30 h.

[0082] (6) Filtration and concentration are performed to obtain the quantum dot fluorescent nanospheres.

[0083] Example 3

[0084] This embodiment provides a method for preparing quantum dot nanospheres, comprising:

[0085] (1) 3 g of quantum dots (ZnCdSe) were dispersed in 7 mL of heptene to obtain an oil phase mixture A1; sodium dodecyl sulfate was dissolved in water to obtain a sodium dodecyl sulfate aqueous solution A2 with a concentration of 3 mg / L.

[0086] (2) 0.5 mL of the oil phase mixture A1 was dispersed in 100 mL of the sodium dodecyl sulfate aqueous solution A2 to form a quantum dot micelle dispersion A3.

[0087] (3) Take 22 g of chlorostyrene and add 0.1 g of oleic acid to form an oil phase mixture B1; dissolve sodium dodecyl sulfate in water to obtain a sodium dodecyl sulfate aqueous solution B2 with a concentration of 2 mg / L.

[0088] (4) The oil phase mixture B1 obtained in step (3) was dispersed in 44 mL of sodium dodecylsulfonate aqueous solution B2 to form a monomer dispersion B3.

[0089] (5) A3 obtained in step (2) and B3 obtained in step (4) were mixed, 30 mL of potassium persulfate aqueous solution (15 mg / L) was added, and the temperature was raised to 80° C. for polymerization for 20 h.

[0090] (6) Filtration and concentration are performed to obtain the quantum dot fluorescent nanospheres.

[0091] Example 4

[0092] The only difference from Example 1 is that oleic acid is replaced by an equal amount of octanethiol.

[0093] After testing, PLQY=92.7%.

[0094] Example 5

[0095] The only difference from Example 1 is that oleic acid is replaced by an equal amount of oleylamine.

[0096] After testing, PLQY=88.7%.

[0097] Example 6

[0098] The only difference from Example 1 is that the amount of oleic acid used in step (3) is 0.05 g.

[0099] After testing, PLQY=92.7%.

[0100] Example 7

[0101] The only difference from Example 1 is that the amount of oleic acid used in step (3) is 0.50 g.

[0102] After testing, PLQY=78.8%.

[0103] Comparative Example 1

[0104] This embodiment provides a method for preparing quantum dot nanospheres, comprising:

[0105] (1) 7 g of quantum dots (ZnCdSe) were dispersed in 3 mL of octane to obtain an oil phase mixture A1; sodium dodecyl sulfate was dissolved in water to obtain a sodium dodecyl sulfate aqueous solution A2 with a concentration of 2 mg / L.

[0106] (2) 1 mL of the oil phase mixture A1 was dispersed in 100 mL of the sodium dodecyl sulfate aqueous solution A2 to form a quantum dot micelle dispersion A3.

[0107] (3) Take 20 g of styrene as the oil phase mixture B1; dissolve sodium dodecyl sulfonate in water to obtain a sodium dodecyl sulfonate aqueous solution B2 with a concentration of 1 mg / L.

[0108] (4) The oil phase mixture B1 obtained in step (3) was dispersed in 50 mL of sodium dodecylsulfonate aqueous solution B2 to form a monomer dispersion B3.

[0109] (5) A3 obtained in step (2) and B3 obtained in step (4) were mixed, 20 mL of potassium persulfate aqueous solution (10 mg / L) was added, and the temperature was raised to 70° C. for polymerization for 24 h.

[0110] (6) Filtration and concentration are performed to obtain the quantum dot fluorescent nanospheres, and the PLQY is tested to be 78.1%.

[0111] The only difference between Comparative Example 1 and Example 1 is that the oil phase mixture B1 does not contain oleic acid, and the PLQY decreases significantly. It can be seen that the addition of the ligand can significantly improve the PLQY of the prepared quantum dot nanospheres.

[0112] The fluorescence intensity of the quantum dot nanospheres prepared in Example 1 and Comparative Example 1 at different wavelengths was tested. Figure 1 As shown, it can be seen that the fluorescence intensity of the quantum dot nanospheres prepared in Example 1 is significantly greater than that in the comparative example.

[0113] The morphology of the product prepared in Example 7 is as follows Figure 2 As shown in the figure, it can be seen that too many ligands will hinder the diffusion of monomers, resulting in the protection of the polymer shell outside the quantum dots, and the PLQY will decrease.

[0114] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A method for preparing quantum dot nanospheres, characterized in that: include: mixing hydrophobic quantum dots, an organic non-coordinating solvent, and a first emulsifier solution to obtain a quantum dot micelle dispersion; mixing the monomer, the ligand, and the second emulsifier solution to obtain a monomer droplet dispersion; polymerizing the quantum dot micelle dispersion and the monomer droplet dispersion in the presence of an initiator; The mass ratio of the monomer to the ligand is 180-220:1; The mass ratio of the quantum dot micelle dispersion to the monomer droplet dispersion is 100:60-80.

2. The preparation method according to claim 1, characterized in that The preparation process of the quantum dot micelle dispersion includes: mixing the hydrophobic quantum dots and the organic non-coordinating solvent to obtain a first oil phase mixture, and mixing the first oil phase mixture with the first emulsifier solution.

3. The preparation method according to claim 2, characterized in that The mass of the hydrophobic quantum dots corresponding to each milliliter of the organic non-coordinating solvent is 0.4 g to 2.3 g.

4. The preparation method according to claim 1, characterized in that The hydrophobic quantum dots are selected from at least one of group II-VI quantum dots, group II-V quantum dots, group III-V quantum dots, group IV-VI quantum dots, group I-VI quantum dots, group I-III-VI quantum dots and group IV quantum dots.

5. The preparation method according to claim 1, characterized in that The organic non-coordinating solvent is selected from at least one of alkanes and their derivatives, alkenes and their derivatives, cycloalkanes and their derivatives, and benzene and its derivatives.

6. The preparation method according to claim 5, characterized in that The organic non-coordinating solvent is at least one selected from hexane or its isomers, heptane or its isomers, octane or its isomers, heptene or its isomers, octene or its isomers, benzene or its isomers, toluene or its isomers, chloroform or its isomers, and tetrachloroethylene or its isomers.

7. The preparation method according to claim 2, characterized in that The first emulsifier solution is an aqueous solution formed by an amphiphilic compound, and the concentration is 1 mg / L-3 mg / L.

8. The preparation method according to claim 7, characterized in that The volume ratio of the first oil phase mixture to the first emulsifier solution is 0.5-2:

100.

9. The preparation method according to claim 8, characterized in that The amphiphilic compound used to prepare the first emulsifier solution is an anionic surfactant.

10. The preparation method according to claim 1, characterized in that The preparation process of the monomer droplet dispersion includes: mixing the monomer and the ligand to obtain a second oil phase mixture, and mixing the second oil phase mixture with the second emulsifier solution.

11. The preparation method according to claim 10, characterized in that: The monomer is selected from at least one of styrene, divinylbenzene, chlorostyrene, methyl methacrylate, ethyl methacrylate, propyl acrylate and butyl acrylate.

12. The preparation method according to claim 10, characterized in that The ligand is selected from at least one of saturated fatty acids, saturated fatty amines, unsaturated fatty acids, unsaturated fatty amines, organic phosphines and thiols.

13. The preparation method according to claim 10, characterized in that The second emulsifier solution is an aqueous solution formed by an amphiphilic compound, and the concentration is 0.5 mg / L-2 mg / L.

14. The preparation method according to claim 10, characterized in that The volume of the second emulsifier solution corresponding to each gram of the second oil phase mixture is 2 mL to 3 mL.

15. The preparation method according to claim 13, characterized in that The amphiphilic compound used to prepare the second emulsifier solution is an anionic surfactant.

16. The preparation method according to claim 1, characterized in that The quantum dot micelle dispersion, the monomer droplet dispersion and the initiator aqueous solution are mixed, and the temperature is raised to 60° C.-80° C. for polymerization.

17. The preparation method according to claim 16, characterized in that The mass ratio of the initiator used to the monomer is 0.05-0.2:10000.

18. The preparation method according to claim 16, characterized in that The initiator is at least one selected from potassium persulfate, azobisisobutylamidine hydrochloride, azobisisobutylimidazoline hydrochloride, azobiscyanovaleric acid and azobisisopropylimidazoline.

19. The preparation method according to claim 16, characterized in that The concentration of the initiator aqueous solution is 5 mg / L-15 mg / L.

20. The preparation method according to claim 16, characterized in that The polymerization time is 20h-30h.

21. The preparation method according to claim 16, characterized in that After the polymerization was completed, the mixture was filtered and concentrated.

22. A quantum dot nanosphere, characterized in that: It is prepared by the preparation method according to any one of claims 1 to 21.

23. Use of the quantum dot nanospheres according to claim 22 in the quantitative detection of biomarkers for purposes other than disease diagnosis and treatment.

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