Amphiphilic branched polymers with aggregation-induced emission effect, nanoparticles and preparation method and application thereof

Abstract

The present application relates to amphiphilic branched polymer with aggregation-induced emission effect, nanoparticles and its preparation method and application, the structure of the amphiphilic branched polymer with aggregation-induced emission effect is: including branched block of polymethacrylate and linear block of polyvinyl, the linear block of polyvinyl is grafted with tetraphenyl ethylene as aggregation-induced emission functional unit and hydrophobic core, and simultaneously grafted with dimethyl formamide as hydrophilic shell, the biocompatibility and safety of nanoparticles prepared from the polymer are enhanced.The present application quickly and efficiently synthesizes amphiphilic branched polymer with aggregation-induced emission effect through reversible addition-fragmentation chain transfer polymerization, and the amphiphilic branched polymer has stronger aggregation-induced emission effect compared with traditional amphiphilic linear polymer, and can be used as more efficient tumor cell fluorescent imaging platform.

Description

Technical Field

[0001] This invention relates to the field of fluorescent polymer materials, specifically to amphiphilic branched polymers and nanoparticles with aggregation-induced emission effects, their preparation methods, and applications. Background Technology

[0002] In recent years, aggregation-induced emission (AIE) materials have attracted widespread attention from researchers in various fields due to their advantages such as convenient synthesis, good modifiability, high biocompatibility, and sensitivity to the external environment. Compared with the shortcomings of aggregation-induced quenching of traditional chemical fluorescent dyes, the "the more aggregated, the more luminescent" property of AIE small molecules is highly favored. Therefore, luminescent polymers prepared based on AIE small molecule monomers have high emission efficiency, sensitive response to the external environment, and good scalability for modification, and are thus applied in fields such as chemical sensing, bioimaging, and drug delivery.

[0003] Self-assembly technology can form multi-unit assemblies with specific ordering or structure through non-covalent interactions between disordered units, enabling the preparation of ordered and stable assemblies at different scales. When self-assembly technology is combined with aggregation-induced emission (AIE), the advantages of each can be fully utilized, broadening the application boundaries of both. Specifically, when amphiphilic polymers using AIE small molecules as hydrophobic segments undergo self-assembly, the intermolecular motion of the hydrophobic small molecules in the core, including rotation and vibration, is effectively restricted. Therefore, when in the excited state, the non-radiative loss of AIE small molecules is limited, and energy can only be emitted in the form of radiative transitions, resulting in continuous and stable fluorescence in the assembly. Therefore, amphiphilic self-assemblies with AIE properties are widely used in cell imaging, drug delivery and tracing, monitoring polymerization processes, and studying self-assembly mechanisms.

[0004] For example, patent publication number CN108559091B discloses a polymer drug carrier with aggregation-induced emission and dual sensitivity, drug-loaded micelles and their preparation method, which discloses an amphiphilic polymer with tetraphenylethylene derivatives as AIE functional units, which can achieve drug loading and monitoring. However, this scheme has the defect that the polymer loses its fluorescence properties after the disulfide bond is broken.

[0005] Traditional linear amphiphilic AIE functional polymers exhibit a sharp decrease in fluorescence of individual linear polymer units after deassembly or detachment of grafted AIE small molecules, failing to maintain strong fluorescence performance efficiently and stably for extended periods.

[0006] Therefore, existing technologies still need to be improved and developed. Summary of the Invention

[0007] In view of the shortcomings of the prior art, the present invention provides amphiphilic branched polymers and nanoparticles with aggregation-induced emission effect, their preparation methods and applications, aiming to solve the problem that traditional linear amphiphilic AIE functional polymers cannot maintain strong fluorescence performance for a long time with high efficiency and stability.

[0008] This invention provides an amphiphilic branched polymer with aggregation-induced emission (AIE) effect, comprising branched blocks of polymethacrylate and linear blocks of polyethylene. The polyethylene blocks are grafted with tetraphenylethylene as the AIE functional unit and a hydrophobic core, and with dimethylformamide as a hydrophilic shell, enhancing the biocompatibility and safety of nanoparticles prepared from the AIE. This invention rapidly and efficiently synthesizes an amphiphilic branched polymer with AIE through a reversible addition-fragmentation chain transfer polymerization reaction. Compared to traditional amphiphilic linear polymers, this amphiphilic branched polymer exhibits a stronger AIE effect and can serve as a more efficient fluorescence imaging platform for tumor cells.

[0009] Specifically, the technical solution of the present invention is as follows: An amphiphilic branched polymer exhibiting aggregation-induced emission effect, wherein the structural formula of the amphiphilic branched polymer exhibiting aggregation-induced emission effect is shown in formula (I): Formula (I); Where 1≤n≤3, 5≤m≤10, and 7≤q≤15, and n, m, and q are all integers.

[0010] A method for preparing an amphiphilic branched polymer with aggregation-induced emission effect as described in this invention, wherein the preparation method includes the following steps: a. Dissolve the chain transfer agent and azobisisobutyronitrile in a solvent and stir the mixture at 70-80℃ for 2-6 hours under an inert atmosphere; the structural formula of the chain transfer agent is shown in formula (II): Formula (II); b. Dissolve tetraphenylethylene monomer and azobisisobutyronitrile in a solvent, and then add them to the mixture obtained in step a. Stir and react at 70-80℃ for 6-20h under an inert atmosphere. After purification, the polymer shown in formula (III) is obtained. Formula (III); c. Dissolve the polymer shown in formula (III), dimethylacrylamide, and azobisisobutyronitrile in a solvent, stir and react at 70-80℃ for 4-19h under an inert atmosphere, and then purify to obtain the amphiphilic branched polymer with aggregation-induced emission effect shown in formula (I).

[0011] Optionally, the method for preparing the chain transfer agent represented by formula (II) includes the following steps: 2-Hydroxyethyl methacrylate, 2-[n-butyltrithiocarbonate]propionic acid, 4-dimethylaminopyridine and tetrahydrofuran were mixed to obtain a mixed solution; Under stirring, a tetrahydrofuran solution of dicyclohexylcarbodiimide was added dropwise to the above mixed solution, and the reaction was carried out for 5 hours. After purification, the chain transfer agent shown in formula (II) was obtained.

[0012] Optionally, in step a, the mass ratio of the chain transfer agent to azobisisobutyronitrile is 17.5:(1.64~4.92).

[0013] Optionally, in step b, the mass ratio of the tetraphenylethyl monomer, chain transfer agent, and azobisisobutyronitrile is (179~358):(17.5~35):(1.64~3.28).

[0014] Optionally, in step c, the mass ratio of the polymer shown in formula (III), dimethacrylamide, and azobisisobutyronitrile is (32~64):(9.913~19.826):(0.3~0.6). A method for preparing nanoparticles using an amphiphilic branched polymer exhibiting aggregation-induced emission effect as described in this invention, comprising the steps of: The amphiphilic branched polymer exhibiting aggregation-induced emission effect was dissolved in a solvent to obtain a branched polymer solution; The branched polymer solution is added to water or physiological saline, shaken, and then the solvent is removed by bubbling with an inert gas to obtain the nanoparticles.

[0015] Optionally, the concentration of the branched polymer solution is 0.1~1 mg / ml, and the volume ratio of the branched polymer solution to water or physiological saline is (9:1)~(6:4).

[0016] Nanoparticles were prepared using the method for preparing nanoparticles with an aggregation-induced emission effect as described in this invention.

[0017] An application of nanoparticles as described in this invention in tumor cell fluorescence imaging.

[0018] Beneficial effects: This invention provides amphiphilic branched polymers and nanoparticles with aggregation-induced emission effect, their preparation methods, and applications. The structure of the amphiphilic branched polymer with aggregation-induced emission effect is as follows: The polymer comprises branched blocks of polymethacrylate and linear blocks of polyethylene. The polyethylene blocks are grafted with tetraphenylethylene as aggregation-induced emission functional units and a hydrophobic core, and with dimethylformamide as a hydrophilic shell, enhancing the biocompatibility and safety of nanoparticles prepared from this polymer. This invention rapidly and efficiently synthesizes amphiphilic branched polymers with aggregation-induced emission effects via a reversible addition-fragmentation chain transfer polymerization reaction. Compared to traditional amphiphilic linear polymers, these branched polymers exhibit stronger aggregation-induced emission effects, and the hydrophilic / hydrophobic units are less prone to detachment, thus preventing deassembly. This makes them suitable as a more efficient and stable fluorescence imaging platform for tumor cells. Attached Figure Description

[0019] Figure 1 The amphiphilic branched polymer with aggregation-induced emission effect prepared in Example 1 of this invention. 1 HNMR spectrum.

[0020] Figure 2 This is a particle size distribution diagram of the amphiphilic branched polymer nanoparticles with aggregation-induced emission effect prepared in Example 5 of the present invention.

[0021] Figure 3 This is a transmission electron microscope image of the amphiphilic branched polymer nanoparticles with aggregation-induced emission effect prepared in Example 5 of the present invention.

[0022] Figure 4 This is the fluorescence emission spectrum of the amphiphilic branched polymer with aggregation-induced emission effect prepared in Example 1 of the present invention.

[0023] Figure 5 The fluorescence emission spectra of the amphiphilic branched polymer nanoparticles with aggregation-induced emission effect prepared in Example 5 and Comparative Example 1 of this invention are shown.

[0024] Figure 6 This is a laser confocal microscope image of tumor cells in the application of fluorescence imaging of tumor cells using the amphiphilic branched polymer nanoparticles with aggregation-induced emission effect prepared in Example 5 of the present invention. Detailed Implementation

[0025] This invention provides amphiphilic branched polymers and nanoparticles with aggregation-induced emission effects, their preparation methods, and applications. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0026] This invention provides an amphiphilic branched polymer with aggregation-induced emission effect, comprising branched blocks of polymethacrylate and linear blocks of polyethylene, wherein the linear blocks of polyethylene are grafted with tetraphenylethylene and dimethylformamide; the structural formula of the amphiphilic branched polymer with aggregation-induced emission effect is shown in formula (I): Formula (I); Where 1≤n≤3, 5≤m≤10, and 7≤q≤15, and n, m, and q are all integers.

[0027] The amphiphilic branched polymer with aggregation-induced emission (AIE) effect described in this embodiment includes branched blocks of polymethacrylate and linear blocks of polyethylene. The polyethylene blocks are grafted with tetraphenylethylene as the aggregation-induced emission functional unit and a hydrophobic core, and simultaneously grafted with dimethylformamide as a hydrophilic shell, enhancing the polymer's biocompatibility and safety. Compared to traditional linear AIE polymers, under the premise of equivalent tetraphenylethylene monomer mass, the branched polymer designed in this embodiment exhibits significantly higher fluorescence intensity in solvents with different water contents (such as tetrahydrofuran) and mixed solvents of water than the linear polymer. Nanoparticles prepared from the branched polymer designed in this embodiment also show significantly improved fluorescence intensity compared to nanoparticles prepared from linear polymers. The use of dimethylformamide as a hydrophilic shell increases the biocompatibility of the nanoparticles, enabling fluorescence imaging and continuous monitoring of tumor cells. Furthermore, the hydrophilic / hydrophobic units are less prone to detachment and deassembly, making it a more efficient and stable fluorescence imaging platform for tumor cells.

[0028] In one embodiment, the degree of polymerization (n) of the branched block copolymer of polymethacrylate is 1, the degree of polymerization (m) of the polyethylene grafted with tetraphenylethylene is 5, and the degree of polymerization (q) of the polyethylene grafted with dimethylformamide is 7-15. Amphiphilic branched polymers with a hydrophilic-to-hydrophobic unit ratio at the above-defined values ​​can self-assemble more efficiently.

[0029] This invention provides a method for preparing an amphiphilic branched polymer with aggregation-induced emission effect, the preparation method comprising the following steps: a. Dissolve the chain transfer agent and azobisisobutyronitrile in a solvent (such as tetrahydrofuran) and react with stirring at 70-80℃ for 2-6 hours under an inert atmosphere (such as nitrogen atmosphere); the structural formula of the chain transfer agent is shown in formula (II): Formula (II); b. Dissolve tetraphenylethylene monomer and azobisisobutyronitrile in a solvent, and then add them to the mixture obtained in step a. Stir and react at 70-80℃ for 6-20h under an inert atmosphere. After purification, the polymer shown in formula (III) is obtained. Formula (III); c. Dissolve the polymer shown in formula (III), dimethylacrylamide, and azobisisobutyronitrile in a solvent, stir and react at 70-80℃ for 4-19h under an inert atmosphere, and then purify to obtain the amphiphilic branched polymer with aggregation-induced emission effect shown in formula (I).

[0030] In this invention, an amphiphilic branched polymer with aggregation-induced emission effect was rapidly and efficiently synthesized via a reversible addition-fragmentation chain transfer polymerization reaction.

[0031] In one embodiment, the method for preparing the chain transfer agent represented by formula (II) includes the following steps: 2-Hydroxyethyl methacrylate, 2-[n-butyltrithiocarbonate]propionic acid, 4-dimethylaminopyridine and tetrahydrofuran were mixed to obtain a mixed solution; Under stirring, a tetrahydrofuran solution of dicyclohexylcarbodiimide was added dropwise to the above mixed solution, and the reaction was carried out for 5 hours. After purification, the chain transfer agent shown in formula (II) was obtained.

[0032] In one embodiment, the purification process includes: dissolving the mixture after the reaction is completed in ethyl acetate, filtering to remove dicyclohexylcarbodiimide, rotary evaporating to remove ethyl acetate, and dissolving in a small amount of dichloromethane and purifying on a silica gel column to obtain the chain transfer agent shown in formula (II).

[0033] In one embodiment, in step a, the mass ratio of the chain transfer agent to azobisisobutyronitrile is 17.5:(1.64~4.92).

[0034] In one embodiment, in step a, the temperature of the stirring reaction is 80°C, and the stirring reaction time is 4 hours.

[0035] In one embodiment, in step b, the mass ratio of the tetraphenylethyl monomer, chain transfer agent, and azobisisobutyronitrile is (179~358):(17.5~35):(1.64~3.28).

[0036] In one embodiment, in step c, the mass ratio of the polymer shown in formula (III), dimethacrylamide, and azobisisobutyronitrile is (32~64):(9.913~19.826):(0.3~0.6).

[0037] This invention provides a method for preparing nanoparticles using amphiphilic branched polymers exhibiting aggregation-induced emission, comprising the following steps: The amphiphilic branched polymer exhibiting aggregation-induced emission effect is dissolved in a solvent (such as tetrahydrofuran) to obtain a branched polymer solution. The branched polymer solution is added (preferably slowly dripped) to water or physiological saline, shaken, and then the solvent is removed by bubbling with an inert gas to obtain the nanoparticles.

[0038] In this embodiment, the nanoparticles obtained by self-assembly of the amphiphilic branched polymer are spherical.

[0039] Tests revealed that the nanoparticles obtained from the self-assembly of amphiphilic branched polymers exhibited two main size distributions, indicating good dispersibility. This is because the amphiphilic branched polymers first self-assemble to form small unit nanoparticles with a diameter of approximately 40 nm, and these small unit nanoparticles can then undergo secondary self-assembly to form multi-unit combined nanoparticles with a diameter of approximately 200 nm.

[0040] In one embodiment, the concentration of the branched polymer solution is 0.1~1 mg / ml, and the volume ratio of the mixed solution to water or physiological saline is (9:1)~(6:4).

[0041] In one embodiment, the inert gas bubbling time is 15-30 minutes.

[0042] This invention provides a method for preparing nanoparticles using the aforementioned amphiphilic branched polymer with aggregation-induced emission effect.

[0043] The embodiments of the present invention provide the application of nanoparticles as described above in tumor cell fluorescence imaging.

[0044] In one embodiment, the tumor cells are the HepG2 liver cancer cell line or the A549 non-small cell lung cancer cell line.

[0045] The present invention will be further described below through specific embodiments.

[0046] Example 1 The specific synthetic route of the amphiphilic branched polymer with aggregation-induced emission effect in this embodiment is shown below:

[0047]

[0048]

[0049]

[0050] The specific synthesis steps of the amphiphilic branched polymer with aggregation-induced emission effect in this embodiment are as follows: (1) 2-Hydroxyethyl methacrylate (0.145 ml, 1.2 mmol), 2-[n-butyltrithiocarbonate]propionic acid (RAFT, 0.238 g, 1 mmol), and 4-dimethylaminopyridine (DMAP, 0.024 g, 0.2 mmol) were mixed in 1 ml of tetrahydrofuran (THF). While stirring, 1 ml of a THF solution of dicyclohexylcarbodiimide (DCC, 0.248 g, 1.2 mmol) was slowly added dropwise to the above mixture, and the reaction was allowed to proceed for 5 h. After the reaction was complete, the resulting mixture was dissolved in 25 ml of ethyl acetate, and the DCC was removed by filtration. The ethyl acetate was removed by rotary evaporation, and the chain transfer agent was purified by dissolving the chain transfer agent in a small amount of dichloromethane and then column-mounting it on a silica gel column.

[0051] (2) Dissolve 17.5 mg of chain transfer agent and 1.64 mg of azobisisobutyronitrile (AIBN) in 200 μl of tetrahydrofuran, freeze and deoxygenate, and stir at 80 °C for 6 h under nitrogen protection.

[0052] (3) Dissolve 179 mg of tetraphenylethylene monomer and 1.64 mg of azobisisobutyronitrile in 300 μl of tetrahydrofuran, add it to the mixture after the reaction in step (2), freeze and vacuum to remove oxygen, stir and react at 80 °C for 20 h under nitrogen protection, and then purify the polymer obtained after the reaction by dropping it into methanol and drying it.

[0053] (4) Dissolve 32 mg of the substance obtained in step (3), 19.826 mg of dimethylacrylamide and 0.3 mg of azobisisobutyronitrile in 200 μl of tetrahydrofuran, freeze and vacuum to remove oxygen, stir and react at 80 °C for 19 h under nitrogen protection, and then drop the polymer obtained after the reaction into anhydrous diethyl ether for purification and drying to obtain the final product Hb-PTPE-b-PDMA.

[0054] The product of this embodiment was subjected to NMR detection (the solvent was deuterated trifluoroacetic acid), and the 1H NMR spectrum is shown below. Figure 1 As shown, through Figure 1 Based on the peak positions and peak area ratios, it can be seen that the amphiphilic branched polymer Hb-PTPE-b-PDMA with aggregation-induced emission effect has been successfully synthesized.

[0055] Example 2 This embodiment is basically the same as Embodiment 1, except that the preparation method of step (4) is as follows: (4) Dissolve 32 mg of the substance obtained in step (3), 9.913 mg of dimethylacrylamide and 0.3 mg of azobisisobutyronitrile in 200 μl of tetrahydrofuran, freeze and vacuum to remove oxygen, stir and react at 80 °C for 19 h under nitrogen protection, and then drop the polymer obtained after the reaction into anhydrous diethyl ether for purification and drying to obtain the product.

[0056] Example 3 This embodiment is basically the same as that of Embodiment 1, except that the preparation methods of steps (3) and (4) are as follows: (3) Dissolve 358 mg of tetraphenylethylene monomer and 1.64 mg of azobisisobutyronitrile in 300 μl of tetrahydrofuran, add it to the mixture after the reaction in step (2), freeze and vacuum to remove oxygen, stir and react at 80 °C for 20 h under nitrogen protection, purify the polymer after the reaction by dripping it into methanol, and dry it.

[0057] (4) Dissolve 64 mg of the substance obtained in step (3), 9.913 mg of dimethylacrylamide and 0.3 mg of azobisisobutyronitrile in 200 μl of tetrahydrofuran, freeze and vacuum to remove oxygen, stir and react at 80 °C for 19 h under nitrogen protection, and then drop the polymer obtained after the reaction into anhydrous diethyl ether for purification and drying to obtain the product.

[0058] Example 4 This embodiment is basically the same as embodiment 3, except that the preparation method of step (4) is as follows: (4) Dissolve 64 mg of the substance obtained in step (3), 19.826 mg of dimethylacrylamide and 0.3 mg of azobisisobutyronitrile in 200 μl of tetrahydrofuran, freeze and vacuum to remove oxygen, stir and react at 80 °C for 19 h under nitrogen protection, and then drop the polymer obtained after the reaction into anhydrous diethyl ether for purification and drying to obtain the product.

[0059] Comparative Example 1 The specific synthetic route of the amphiphilic linear polymer exhibiting aggregation-induced emission effect in this comparative example is shown below:

[0060] The specific synthesis steps of the amphiphilic linear polymer exhibiting aggregation-induced emission effect in this comparative example are shown below: (1) Dissolve 11.9 mg of chain transfer agent, 1.64 mg of azobisisobutyronitrile and 179 mg of tetraphenylethylene monomer in 500 μl of tetrahydrofuran, freeze and deoxygenate, and stir at 80 °C under nitrogen protection. The structural formula of the chain transfer agent is shown in formula (IV): Formula (IV) (2) Dissolve 32 mg of the substance obtained in step (1), 19.826 mg of dimethylacrylamide and 0.3 mg of azobisisobutyronitrile in 200 μl of tetrahydrofuran, freeze and vacuum to remove oxygen, stir and react at 80 °C for 19 h under nitrogen protection, and then drop the polymer obtained after the reaction into anhydrous diethyl ether for purification and drying to obtain the product L-PTPE-b-PDMA.

[0061] Example 5 A method for preparing nanoparticles using the amphiphilic branched polymer Hb-PTPE-b-PDMA with aggregation-induced emission effect specifically includes the following steps: 1 mg of polymer Hb-PTPE-b-PDMA from Example 1 was dissolved in 100 μl of tetrahydrofuran. 100 μl of the polymer tetrahydrofuran solution was added dropwise to 900 μl of deionized water. The mixture was shaken for 1 min to mix thoroughly. The tetrahydrofuran was removed by argon bubbling for 15 min. The polymer dispersion after removing the tetrahydrofuran was brought to a final volume of 1 ml to obtain a 1 mg / ml nanoparticle dispersion.

[0062] Example 6 A method for preparing nanoparticles using the amphiphilic linear polymer L-PTPE-b-PDMA with aggregation-induced emission effect specifically includes the following steps: 1 mg of polymer L-PTPE-b-PDMA from Comparative Example 1 was dissolved in 100 μl of tetrahydrofuran. 100 μl of the polymer tetrahydrofuran solution was added dropwise to 900 μl of deionized water. The mixture was shaken for 1 min to mix thoroughly. The tetrahydrofuran was removed by argon bubbling for 15 min. The polymer dispersion after removing the tetrahydrofuran was brought to a final volume of 1 ml to obtain a 1 mg / ml nanoparticle dispersion.

[0063] To test the particle size and distribution of nanoparticles prepared from amphiphilic branched polymers, the nanoparticle dispersion from Example 5 was diluted with deionized water to 0.1 mg / ml, and the particle size distribution was measured using a Malvern particle size analyzer. The results are as follows: Figure 2 As shown. By Figure 2 It can be seen that the particle size distribution of nanoparticles prepared from amphiphilic branched polymers is concentrated at around 40 nm and 200 nm. This indicates that the single amphiphilic branched polymer first self-assembles into small unit nanoparticles of about 40 nm, and these small unit nanoparticles can then undergo secondary self-assembly to form multi-unit combined nanoparticles of 200 nm. Therefore, it can be concluded that nanoparticles prepared from amphiphilic branched polymers have two particle size distributions and good dispersibility.

[0064] To observe the specific morphology of the nanoparticles prepared from the amphiphilic branched polymer, the nanoparticle dispersion from Example 5 was diluted with deionized water to 0.1 mg / ml. 10 μl of the diluted dispersion was dropped onto a copper grid and deposited for 40 min to allow the nanoparticles to adhere to the carbon film. The nanoparticles were then negatively stained with 10% phosphotungstic acid solution for 5 min, the phosphotungstic acid solution was removed, and the nanoparticles were air-dried for 48 h. The morphology of the nanoparticles was observed using a T12 transmission electron microscope. The transmission electron microscope image is shown below. Figure 3 As shown. By Figure 3It can be seen that the nanoparticles prepared from the amphiphilic branched polymer have two sizes of regular spherical particles, namely spherical structures of about 50 nm and 200 nm, respectively. This characterization result is consistent with... Figure 2 The particle size test results are basically consistent.

[0065] To test the aggregation-induced emission (AIE) properties of the amphiphilic branched polymer Hb-PTPE-b-PDMA and compare its strength with that of the amphiphilic linear polymer L-PTPE-b-PDMA, a method was used to gradually change the water content in the mixed solvent system. First, a mixed solvent of tetrahydrofuran and water was prepared, with the water content increasing sequentially from 10% to 90%. Polymers prepared in Example 1 and Comparative Example 1 were added to the mixed solvent, with the polymer concentration fixed at 0.1 mg / ml. The fluorescence intensity of the two polymers in the mixed solvents with different water contents was measured using a fluorescence spectrometer. The excitation wavelength was 360 nm, and the emission wavelength was 470 nm. The AIE test results are shown below. Figure 4 As shown.

[0066] Depend on Figure 4 It can be seen that both polymers exhibit good aggregation-induced emission properties, and the fluorescence intensity increases with increasing water content. In mixed solvents with different water contents, the fluorescence intensity of the amphiphilic branched polymer Hb-PTPE-b-PDMA is significantly stronger than that of the amphiphilic linear polymer L-PTPE-b-PDMA.

[0067] To compare the aggregation-induced emission (AIE) of nanoparticles prepared from the amphiphilic branched polymer Hb-PTPE-b-PDMA and the amphiphilic linear polymer L-PTPE-b-PDMA, the nanoparticle dispersion from Example 5 was diluted with deionized water to 0.1 mg / ml, and the nanoparticle dispersion from Example 6 was diluted with deionized water to 0.1 mg / ml. The fluorescence intensity of the two types of nanoparticles was measured using a fluorescence spectrometer with an excitation wavelength of 360 nm and an emission wavelength of 470 nm. The results of the nanoparticle luminescence performance test are as follows: Figure 5 As shown. By Figure 5 It can be seen that the nanoparticles prepared by both polymers have good aggregation-induced emission properties. The fluorescence intensity of the nanoparticles prepared by the amphiphilic branched polymer Hb-PTPE-b-PDMA is significantly stronger than that of the nanoparticles prepared by the amphiphilic linear polymer L-PTPE-b-PDMA.

[0068] To investigate the application of Hb-PTPE-b-PDMA nanoparticles, an amphiphilic branched polymer with aggregation-induced emission, in tumor cell fluorescence imaging, the nanoparticle dispersion from Example 5 was diluted to 20 μg / ml with DMEM culture medium. The culture medium was then co-incubated with the HepG2 liver cancer cell line and the A549 non-small cell lung cancer cell line for 4 h. Fluorescence imaging of the tumor cells was observed using a laser scanning confocal microscope. The results are as follows: Figure 6 As shown. By Figure 6 It is evident that nanoparticles prepared from amphiphilic branched polymers have the potential for tumor cell imaging.

[0069] In summary, this invention rapidly and efficiently synthesizes an amphiphilic branched polymer with aggregation-induced emission (AIE) via a reversible addition-fragmentation chain transfer polymerization reaction. This polymer comprises branched blocks of polymethacrylate and linear blocks of polyethylene. The polyethylene blocks are grafted with tetraphenylethylene as the AIE functional unit and a hydrophobic core, while dimethylformamide is grafted as a hydrophilic shell, enhancing the biocompatibility and safety of the nanoparticles. Compared to traditional amphiphilic linear polymers, the amphiphilic branched polymer of this invention exhibits a stronger AIE effect. Nanoparticles prepared based on this AIE-based amphiphilic branched polymer have the potential for tumor cell imaging and can serve as a more efficient tumor cell fluorescence imaging platform.

[0070] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. An amphiphilic branched polymer exhibiting aggregation-induced emission effect, characterized in that, The structural formula of the amphiphilic branched polymer with aggregation-induced emission effect is shown in formula (I): Equation (I); Where 1≤n≤3, 5≤m≤10, and 7≤q≤15, and n, m, and q are all integers.

2. A method for preparing an amphiphilic branched polymer with aggregation-induced emission effect as described in claim 1, characterized in that, The preparation method includes the following steps: a. Dissolve the chain transfer agent and azobisisobutyronitrile in a solvent and stir the mixture at 70-80℃ for 2-6 hours under an inert atmosphere; the structural formula of the chain transfer agent is shown in formula (II): Formula (II); b. Dissolve tetraphenylethylene monomer and azobisisobutyronitrile in a solvent, and then add them to the mixture obtained in step a. Stir and react at 70-80℃ for 6-20h under an inert atmosphere. After purification, the polymer shown in formula (III) is obtained. Formula (III); c. Dissolve the polymer shown in formula (III), dimethylacrylamide, and azobisisobutyronitrile in a solvent, stir and react at 70-80℃ for 4-19h under an inert atmosphere, and then purify to obtain the amphiphilic branched polymer with aggregation-induced emission effect shown in formula (I).

3. The method for preparing the amphiphilic branched polymer with aggregation-induced emission effect according to claim 2, characterized in that, The method for preparing the chain transfer agent represented by formula (II) includes the following steps: 2-Hydroxyethyl methacrylate, 2-[n-butyltrithiocarbonate]propionic acid, 4-dimethylaminopyridine and tetrahydrofuran were mixed to obtain a mixed solution; Under stirring, a tetrahydrofuran solution of dicyclohexylcarbodiimide was added dropwise to the above mixed solution, and the reaction was carried out for 5 hours. After purification, the chain transfer agent shown in formula (II) was obtained.

4. The method for preparing the amphiphilic branched polymer with aggregation-induced emission effect according to claim 2, characterized in that, In step a, the mass ratio of the chain transfer agent to azobisisobutyronitrile is 17.5:(1.64~4.92).

5. The method for preparing the amphiphilic branched polymer with aggregation-induced emission effect according to claim 2, characterized in that, In step b, the mass ratio of the tetraphenylethyl monomer, chain transfer agent, and azobisisobutyronitrile is (179~358):(17.5~35):(1.64~3.28).

6. The method for preparing the amphiphilic branched polymer with aggregation-induced emission effect according to claim 2, characterized in that, In step c, the mass ratio of the polymer shown in formula (III), dimethacrylamide, and azobisisobutyronitrile is (32~64):(9.913~19.826):(0.3~0.6).

7. A method for preparing nanoparticles using the amphiphilic branched polymer with aggregation-induced emission effect as described in claim 1, characterized in that, Including the following steps: The amphiphilic branched polymer exhibiting aggregation-induced emission effect was dissolved in a solvent to obtain a branched polymer solution; The branched polymer solution is added to water or physiological saline, shaken, and then the solvent is removed by bubbling with an inert gas to obtain the nanoparticles.

8. The method for preparing nanoparticles from amphiphilic branched polymers exhibiting aggregation-induced emission effect according to claim 7, characterized in that, The concentration of the branched polymer solution is 0.1~1 mg / ml, and the volume ratio of the branched polymer solution to water or physiological saline is (9:1)~(6:4).

9. Nanoparticles prepared using the method for preparing nanoparticles with an amphiphilic branched polymer having aggregation-induced emission effect as described in any one of claims 7-8.

10. The application of the nanoparticles as described in claim 9 in tumor cell fluorescence imaging for purposes other than disease diagnosis or treatment.

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