Thermosensitive amphiphilic triblock polymer, preparation method, application thereof and drug-loaded micelle

Abstract

The present invention provides a thermoresponsive amphiphilic triblock polymer, a preparation method, an application thereof, and a drug-loaded micelle. A thermoresponsive amphiphilic triblock polymer P(PFPHM9-b-DMAA-b-PEGMA is prepared by using activators regenerated by electron transfer for atom transfer radical polymerization (ARGET ATRP). 360 ) The thermoresponsive amphiphilic triblock polymer P(PFPHM9-b-DMAA-b-PEGMA 360 ) has temperature sensitivity and a low critical micelle concentration, and has no biological toxicity, and can be used as a drug carrier for doxorubicin. The P(PFPHM9-b-DMAA-b-PEGMA 360 ) of the present invention can effectively encapsulate DOX, thereby obtaining a thermoresponsive amphiphilic triblock polymer drug-loaded micelle. The drug-loaded micelle has a slow drug release at 37°C, which is beneficial to the circulation of the drug in the body, reduces the dosage of the drug and the side effects of the drug on the human body, while the drug is rapidly released at 42°C, which is beneficial to acting on the patient position in a short time and reducing the treatment time.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer preparation, and particularly to an amphiphilic triblock polymer with thermal responsiveness, a preparation method thereof, an application thereof, and a drug-loaded micelle. Background Art

[0002] Cancer has been studied for decades, but it remains one of the most intractable diseases globally. Chemotherapy is one of the traditional methods for non-targeted treatment of malignant tumors. In chemotherapy, the non-specific behavior of drugs can cause toxic side effects to users, especially damaging normal tissue cells. Therefore, improving the utilization rate and selectivity of drugs for cancer cells is crucial for enhancing the efficacy of anti-cancer drugs.

[0003] Nanomicelles are good carriers for the anti-cancer drug doxorubicin (DOX). They have received great attention because they can release hydrophobic drug molecules in a controlled manner. Among them, nanoscale drug-loaded micelles self-assembled from amphiphilic polymers have great potential in cancer treatment. They can release drugs under specific conditions, achieving targeted drug release and control, thereby improving the therapeutic response and reducing side effects on the body.

[0004] The tumor microenvironment has physiological characteristics such as weak acidity, low oxygen, and up-regulated expression of certain enzymes compared to normal cells, and the temperature of tumor tissue is higher than that of normal physiological tissue. These differences provide new research directions for thermoresponsive nano-targeted preparations. In existing research, some researchers synthesized an amphiphilic block polymer poly(ethylene glycol)-poly(ε-caprolactone) with pH sensitivity for transporting doxorubicin. In addition, some researchers synthesized amphiphilic chitosan derivatives for loading vitamin B12. Research shows that when the critical micelle concentration (CMC) of micelles is relatively high, when the drug-loaded micelles reach the tumor tissue, the micelles will suddenly release drugs or even burst. This phenomenon occurs because the micelles are unstable after dilution and cannot form micelles after reaching the tumor tissue cells. And the slow and continuous release of drugs from the micelles can extend the action period of the drugs on cancer cells, reduce the dosage of drugs required, and even inhibit toxic side effects. Summary of the Invention

[0005] The purpose of the present invention is to provide an amphiphilic triblock polymer with thermal responsiveness, which has temperature sensitivity, a relatively low critical micelle concentration, and no biological toxicity, and can be used as a drug carrier for doxorubicin.

[0006] Another purpose of the present invention is to provide a preparation method of an amphiphilic triblock polymer with thermal responsiveness. By using triple electron transfer activation regenerative catalyst atom transfer radical polymerization, an amphiphilic triblock polymer P(PFPHM9-b-DMAA-b-PEGMA) with thermal responsiveness is prepared. 360), with controllable parameters and suitable for large-scale industrial production.

[0007] The present invention provides the application of the above-mentioned thermoresponsive amphiphilic triblock polymer in the preparation of doxorubicin drugs with drug sustained-release function.

[0008] The present invention also provides a thermoresponsive amphiphilic triblock polymer drug-loaded micelle and a preparation method thereof. As a doxorubicin drug-loaded micelle, the drug-loaded micelle can achieve the purpose of drug sustained release.

[0009] The present invention solves its technical problems by adopting the following technical solutions.

[0010] The present invention provides a preparation method of a thermoresponsive amphiphilic triblock polymer, including the following steps:

[0011] S1. React perfluoropolyether acyl fluoride with 2-hydroxyethyl methacrylate to obtain perfluoropolyether acyl fluoride 2-hydroxyethyl methacrylate containing an olefin structure;

[0012] S2. Use ethyl 2-bromoisobutyrate to initiate the self-polymerization of perfluoropolyether acyl fluoride 2-hydroxyethyl methacrylate and introduce a terminal bromine atom to obtain a macroinitiator PPFPHM-Br;

[0013] S3. Introduce a thermoresponsive functional monomer DMAA into the macroinitiator PPFPHM-Br to obtain P(PFPHM9-b-DMAA)-Br;

[0014] S4. Use the P(PFPHM9-b-DMAA)-Br as a thermoresponsive macroinitiator to introduce a hydrophilic segment PEGMA 360 , to obtain a thermoresponsive amphiphilic triblock polymer P (PFPHM9-b-DMAA-b-PEGMA 360 ).

[0015] The present invention provides a thermoresponsive amphiphilic triblock polymer prepared according to the above preparation method.

[0016] The present invention provides the application of the above-mentioned thermoresponsive amphiphilic triblock polymer in the preparation of doxorubicin drugs with drug sustained-release function.

[0017] The present invention provides a preparation method of a thermoresponsive amphiphilic triblock polymer drug-loaded micelle, including the following steps:

[0018] Dissolve doxorubicin hydrochloride in an acetone solution, and then add the thermoresponsive amphiphilic triblock polymer P(PFPHM9-b-DMAA-b-PEGMA 360) Add the acetone solution, disperse it by ultrasonic wave, then drop it into deionized water, dialyze it in the dark for 24 - 30 h, and then freeze-dry it to obtain a thermoresponsive amphiphilic triblock polymer drug-loaded micelle.

[0019] The present invention provides a thermoresponsive amphiphilic triblock polymer drug-loaded micelle, which is prepared according to the above preparation method.

[0020] The beneficial effects of the thermoresponsive amphiphilic triblock polymer, its preparation method, application and drug-loaded micelle in the embodiments of the present invention are as follows:

[0021] 1. The present invention uses atom transfer radical polymerization of three electron transfer activation regeneration catalysts to prepare poly(2-hydroxyethyl perfluorooctanoyl fluoride polyether methacrylate 9)-b-poly(dimethylacrylamide)-b-poly(polyethylene glycol methacrylate 360), that is, a thermoresponsive amphiphilic triblock polymer P(PFPHM9-b-DMAA-b-PEGMA 360 )). This P(PFPHM9-b-DMAA-b-PEGMA 360 ) has temperature sensitivity and a low critical micelle concentration, thus providing a theoretical basis for the development of an efficient controlled-release anticancer drug delivery system based on temperature-responsive copolymers. In addition, P(PFPHM9-b-DMAA-b-PEGMA 360 ) has no biological toxicity, so it can be used as a drug carrier for doxorubicin.

[0022] 2. The critical micelle concentration value of the P(PFPHM9-b-DMAA-b-PEGMA 360 ) polymer self-assembled into micelles in an aqueous medium is 1.0 μg / L. It has a low critical micelle concentration, far lower than that of conventional carbon-chain amphiphilic polymers. The core-shell structure of the P(PFPHM9-b-DMAA-b-PEGMA 360 ) aqueous solution is relatively stable. Even at a low concentration, it can maintain a complete structure, which is beneficial to prolong its circulation time in the human body.

[0023] 3. The drug loading amount of the thermoresponsive amphiphilic triblock polymer drug-loaded micelle of the present invention is 20.6%, the encapsulation rate is 86.7%, and the critical solution temperature is 39 °C. Its drug release rates at 42 °C and 37 °C are 95.9% and 33.5% respectively. The drug-loaded micelle releases drugs slowly at 37 °C, which is beneficial to the circulation of drugs in the body, reduces the dosage of drugs and the side effects of drugs on the human body. While at 42 °C, the drug is released rapidly, which is beneficial to act on the patient's position in a short time and reduce the treatment time. It is a very promising drug carrier for doxorubicin. Description of the Drawings

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the embodiments. It should be understood that the following drawings only show certain embodiments of the present invention, and therefore should not be regarded as a limitation of the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0025] Figure 1 Synthesis route diagram of the thermoresponsive amphiphilic triblock polymer P(PFPHM9-b-DMAA-b-PEGMA 360 ) for the embodiments of the present invention;

[0026] Figure 2 1H NMR spectra of HEMA, PFPHM, PPFPHM9-Br, P(PFPHM9-b-DMAA)-Br, and P(PFPHM9-b-DMAA-b-PEGMA 360 ) for Example 1 of the present invention; 1 1H NMR spectra;

[0027] Figure 3 Infrared spectra of HEMA, PPFPHM9-Br, P(PFPHM9-b-DMAA)-Br, and P(PFPHM9-b-DMAA-b-PEGMA 360 ) for Example 1 of the present invention;

[0028] Figure 4 Transmittance change curve of P(FPHM9-b-DMAA-b-PEGMA 360 ) for Example 1 of the present invention;

[0029] Figure 5 Relationship between fluorescence intensity and wavelength of P(PFPHM9-b-DMAA-b-PEGMA 360 ) for Example 1 of the present invention;

[0030] Figure 6 For Figure 5 Relationship between I338.4 / I336.1 and logarithm of concentration of P(PFPHM9-b-DMAA-b-PEGMA 360 ) in

[0031] Figure 7 Comparison diagram of CMC of P(PFPHM9-b-DMAA-b-PEGMA 360 ) for Example 1 of the present invention and amphiphilic polymers of Comparative Examples 1-5;

[0032] Figure 8 Particle size distribution diagram of drug-loaded micelles for Example 4 of the present invention and blank micelles of Comparative Example 6;

[0033] Figure 9 TEM images of the drug-loaded micelles of Example 4 of the present invention and the blank micelles of Comparative Example 6;

[0034] Figure 10 P(PFPHM9-b-DMAA-b-PEGMA 360 ) drug-loaded micelles of Example 4 of the present invention at 37 °C;

[0035] Figure 11 P(PFPHM9-b-DMAA-b-PEGMA 360 ) drug-loaded micelles of Example 4 of the present invention at 42 °C;

[0036] Figure 12 P(PFPHM9-b-DMAA-b-PEGMA 360 )-DOX drug-loaded micelles, doxorubicin and P(PFPHM9-b-DMAA-b-PEGMA 360 ) blank micelles of Comparative Example 6 against HepG2 cell growth inhibition rate curve. Detailed implementation manners

[0037] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Those not specified in the embodiments are carried out according to conventional conditions or conditions recommended by the manufacturer. Reagents or instruments not specified by the manufacturer are all conventional products that can be obtained through commercial purchase.

[0038] The thermoresponsive amphiphilic triblock polymer of the embodiments of the present invention, its preparation method, application and drug-loaded micelles will be specifically described below.

[0039] Referring to Figure 1 As shown, a preparation method of a thermoresponsive amphiphilic triblock polymer provided by an embodiment of the present invention includes the following steps:

[0040] S1. React perfluoropolyether acyl fluoride with 2-hydroxyethyl methacrylate to obtain perfluoropolyether acyl fluoride 2-hydroxyethyl methacrylate (PFPHM) containing an olefin structure. Perfluoropolyether acyl fluoride not only has superhydrophobic properties but also has no accumulation in the body. In addition, it has almost no biological toxicity.

[0041] Furthermore, in a preferred embodiment of the present invention, the specific steps for synthesizing the perfluoropolyether acyl fluoride 2-hydroxyethyl methacrylate include:

[0042] Place the hydroxyethyl methacrylate, 2,2,2-trifluoroethanol and triethylamine in a first reaction vessel, stir and mix them, then dropwise add the mixed solution of perfluoropolyether acyl fluoride and 2,2,2-trifluoroethanol under constant pressure. After reacting at 25-30 °C for 8-10 h, extract and wash with dilute hydrochloric acid, take the lower layer and extract and wash with ultrapure water for multiple times to obtain the perfluoropolyether acyl fluoride hydroxyethyl methacrylate.

[0043] Further, in a preferred embodiment of the present invention, the molar ratio of the perfluoroacyl fluoride polyether to the hydroxyethyl methacrylate is 1.5-2:1.

[0044] S2. Use ethyl 2-bromoisobutyrate to initiate the self-polymerization of the perfluoropolyether acyl fluoride hydroxyethyl methacrylate and introduce a terminal bromine atom to obtain a macromolecular initiator PPFPHM-Br.

[0045] Further, in a preferred embodiment of the present invention, the specific steps for synthesizing the macromolecular initiator PPFPHM-Br include:

[0046] S21. Place 2,2,2-trifluoroethanol, N,N,N',N'',N''-pentamethyldiethylenetriamine and copper bromide in a second reaction vessel. After ultrasonic washing to dissolve and disperse the copper bromide, add the perfluoropolyether acyl fluoride hydroxyethyl methacrylate and ethyl 2-bromoisobutyrate. After sealing and stirring for 10-20 min, add stannous octoate, and degas the reaction vessel with liquid nitrogen to remove oxygen through three cycles of liquid nitrogen freezing - vacuum pumping - thawing; wherein, the molar ratio of ethyl 2-bromoisobutyrate to the perfluoropolyether acyl fluoride hydroxyethyl methacrylate is 1:9-10.

[0047] S22. Fill the second reaction vessel with high-purity nitrogen, seal it and transfer it to an oil bath at 40-50 °C for reaction for 9-10 h. Cool and dilute the reaction system with absolute ethanol to obtain a first reaction solution.

[0048] S23. Using absolute ethanol as an eluent, pass the first reaction solution through a neutral alumina column with a mesh size of 180-220 to remove copper bromide, then dropwise add it to an excessive and rapidly stirred deionized water / ethanol mixed solution. After centrifugal separation, pour off the supernatant to collect the precipitate, and then wash it repeatedly to remove unreacted monomers. Finally, dry the collected precipitate to obtain the macromolecular initiator PPFPHM-Br.

[0049] Fluoropolymers have both oleophobicity and extremely strong hydrophobicity, thermal stability and chemical stability, gas solubility, high fluidity, low dielectric constant, and low surface energy, and exhibit a highly stable self-assembly ability. Compared with conventional carbon-chain amphiphilic polymers, fluorocarbon-chain amphiphilic polymers have a lower CMC value, thus enhancing the stability of micelles to extend the drug release time.

[0050] S3. Introduce the thermoresponsive functional monomer DMAA into the macromolecular initiator PPFPHM-Br to obtain P(PFPHM9-b-DMAA)-Br.

[0051] Furthermore, in a preferred embodiment of the present invention, the specific steps for introducing the thermoresponsive functional monomer DMAA into the macromolecular initiator PPFPHM-Br include:

[0052] S31. Place the macromolecular initiator PPFPHM-Br, copper bromide, N,N,N',N'',N''-pentamethyldiethylenetriamine, N,N-dimethylacrylamide, stannous 2-ethylhexanoate, and 2,2,2-trifluoroethanol in a third reaction vessel, and degas the reactor using liquid nitrogen to remove oxygen through three cycles of liquid nitrogen freezing - vacuum pumping - thawing;

[0053] S32. Fill the third reaction vessel with high-purity nitrogen, seal it, and transfer it to an oil bath at 40 - 50 °C for reaction for 9 - 10 h. Cool and dilute the reaction system with absolute ethanol to obtain a second reaction solution;

[0054] S33. Using absolute ethanol as the eluent, pass the second reaction solution through a neutral alumina column with a mesh size of 180 - 220 to remove copper bromide, then dropwise add it into an excess and rapidly stirred mixed solution of deionized water / ethanol. After centrifugal separation, pour off the supernatant to collect the precipitate, and then wash it repeatedly to remove unreacted monomers. Finally, dry the collected precipitate to obtain the macromolecular initiator P(PFPHM9-b-DMAA)-Br.

[0055] S4. Introduce the hydrophilic segment PEGMA using the P(PFPHM9-b-DMAA)-Br as the thermoresponsive macromolecular initiator 360 , to obtain a thermoresponsive amphiphilic triblock copolymer P(PFPHM9-b-DMAA-b-PEGMA 360 ).

[0056] Furthermore, in a preferred embodiment of the present invention, the specific steps for introducing the hydrophilic segment PEGMA using the P(PFPHM9-b-DMAA)-Br as the thermoresponsive macromolecular initiator 360 include:

[0057] S41. Place the P(PFPHM9-b-DMAA)-Br, copper bromide, N,N,N',N'',N''-pentamethyldiethylenetriamine, polyethylene glycol methacrylate, stannous 2-ethylhexanoate, and 2,2,2-trifluoroethanol in a fourth reaction vessel, and degas the fourth reaction vessel using liquid nitrogen to remove oxygen through three cycles of liquid nitrogen freezing - vacuum pumping - thawing;

[0058] S42. Charge high-purity nitrogen into the fourth reaction vessel, seal it, and transfer it to an oil bath at 40-50 °C for reaction for 9-10 h. Cool it and dilute the reaction system with absolute ethanol to obtain the third reaction solution;

[0059] S43. Using absolute ethanol as the eluent, pass the third reaction solution through a neutral alumina column with a mesh size of 180-220 to remove copper bromide, and then dropwise add it into an excessive and rapidly stirred deionized water / ethanol mixed solution. After centrifugal separation, pour off the supernatant to collect the precipitate, and then wash it repeatedly many times to remove unreacted monomers. Finally, dry the collected precipitate to obtain the thermoresponsive amphiphilic triblock copolymer P(PFPHM9-b-DMAA-b-PEGMA 360 ).

[0060] The perfluoropolyether acyl fluoride (HFPO) used in the present invention is purchased from Sanming Haisifu Chemical Co., Ltd. Triethylamine (TEA), doxorubicin hydrochloride (DOX / HCl), 2-hydroxyethyl methacrylate (HEMA), acetone, methanol, copper bromide (CuBr2), ethyl 2-bromoisobutyrate (EBIB), 2,2,2-trifluoroethanol (TFEA), absolute ethanol (C2H5OH), stannous octoate (Sn(Oct)2), N,N,N',N'',N''-pentamethyldiethylenetriamine (PMDETA), n-hexane (C6H 12 ), N,N-dimethylacrylamide (DMAA), polyethylene glycol methacrylate (Mn = 360 g / mol, PEGMA 360 ), potassium bromide (KBr), deuterated acetone, hydrochloric acid (HCl), deuterated chloroform (CDCl3), dimethyl sulfoxide-d6 (DMSO-d6), dimethyl sulfoxide (DMSO), potassium dihydrogen phosphate, disodium hydrogen phosphate, neutral alumina (200 mesh), and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and other drugs are all analytical pure reagents and are purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0061] The present invention prepares P(PFPHM9-b-DMAA-b-PEGMA 360 ) by three-electron transfer activation regenerative catalyst atom transfer radical polymerization, which has temperature sensitivity and a low critical micelle concentration, and has no biological toxicity and can be used as a drug carrier for doxorubicin.

[0062] The present invention also provides a thermoresponsive amphiphilic triblock copolymer prepared according to the above preparation method.

[0063] The present invention also provides the application of the above thermoresponsive amphiphilic triblock copolymer in the preparation of a doxorubicin drug with a drug slow-release function.

[0064] The present invention also provides a preparation method of a thermoresponsive amphiphilic triblock polymer drug-loaded micelle, comprising the following steps:

[0065] Dissolve doxorubicin hydrochloride in an acetone solution, and then add the thermoresponsive amphiphilic triblock polymer P(PFPHM9-b-DMAA-b-PEGMA 360 ) to the acetone solution. After ultrasonic dispersion, drop it into deionized water, dialyze in the dark for 24 - 30 h, and then freeze-dry to obtain a thermoresponsive amphiphilic triblock polymer drug-loaded micelle.

[0066] The present invention also provides a thermoresponsive amphiphilic triblock polymer drug-loaded micelle, which is prepared according to the above preparation method. The drug loading amount of the drug-loaded micelle is 20.6%, the encapsulation efficiency is 86.7%, and the critical solution temperature is 39°C. Its drug release rates at 42°C and 37°C are 95.9% and 33.5% respectively. The drug-loaded micelle can be used as a doxorubicin drug-loaded micelle to achieve the purpose of drug sustained release.

[0067] The features and properties of the present invention are further described in detail below in conjunction with examples.

[0068] Example 1

[0069] A thermoresponsive amphiphilic triblock polymer provided in this example is prepared according to the following method:

[0070] (1) Preparation of perfluoropolyether acyl fluoride 2-hydroxyethyl methacrylate (PFPHM): Add 2-hydroxyethyl methacrylate (40 mmol), 2,2,2-trifluoroethanol (50 mL) and triethylamine (40 mmol) to a reaction vessel, stir and mix for 10 min, and then use a constant pressure dropping funnel to drop a mixed solution of perfluoropolyether acyl fluoride and 2,2,2-trifluoroethanol. Among them, the amount of perfluoropolyether acyl fluoride added to the mixed solution is 80 mmol, and the volume of 2,2,2-trifluoroethanol is 30 mL. React at 25 - 30°C for 8 - 10 h, extract and wash with dilute hydrochloric acid with a concentration of 0.1 mol / L, take the lower layer, and then extract and wash with ultrapure water for multiple times to obtain perfluoropolyether acyl fluoride 2-hydroxyethyl methacrylate.

[0071] (2) Synthesis of macromolecular initiator PPFPHM-Br: Add 2,2,2-trifluoroethanol (50 mL), N,N,N',N'',N''-pentamethyldiethylenetriamine (2 mmol), and copper bromide (0.2 mmol) into the reaction vessel. After ultrasonic washing for 5 min to dissolve and disperse copper bromide, add perfluoroyl fluoride polyether hydroxyethyl methacrylate (PFPHM) prepared in step (1) and ethyl 2-bromoisobutyrate into the reaction vessel. Among them, 20 mmol of perfluoroyl fluoride polyether hydroxyethyl methacrylate is added to the mixed solution, and 2 mmol of ethyl 2-bromoisobutyrate is added. After sealing and stirring for 10 - 20 min, add 2 mmol of stannous octoate, and immediately transfer the flask to a Dewar flask filled with liquid nitrogen for degassing. Remove oxygen by three cycles of liquid nitrogen freezing - vacuum pumping - thawing. Subsequently, fill the reaction vessel with high-purity nitrogen, seal it, and transfer it to an oil bath at 40 - 50 °C for reaction for 9 - 10 h. After the reaction is completed, cool it, dilute the reaction system with 30 mL of absolute ethanol. Using absolute ethanol as the eluent, pass the diluted reaction solution through a 200-mesh neutral alumina column to remove copper bromide. Drop the collected solution drop by drop into an excess and rapidly stirred mixed solution of deionized water / ethanol (volume ratio 3:1), centrifuge, pour off the supernatant, collect the precipitate, wash it repeatedly many times to remove unreacted monomers, and dry the collected precipitate at 60 °C for 24 h to obtain a solid, which is the macromolecular initiator PPFPHM-Br.

[0072] (3) Synthesis of temperature-sensitive functional macromolecular initiator P(PFPHM9-b-DMAA)-Br: Place PPFPHM-Br (0.6 g) prepared in step (2), copper bromide (0.05 mmol), N,N,N',N'',N''-pentamethyldiethylenetriamine (0.05 mmol), N,N-dimethylacrylamide (40 mmol), stannous octoate (0.5 mmol), and 2,2,2-trifluoroethanol (30 mL) in a container. Remove oxygen in the reaction vessel by three cycles of liquid nitrogen freezing - vacuum pumping - thawing. Subsequently, fill the reaction vessel with high-purity nitrogen, seal it, and transfer it to an oil bath at 40 - 50 °C for reaction for 9 - 10 h. After the reaction is completed, cool it, dilute the reaction system with absolute ethanol. Using absolute ethanol as the eluent, pass the diluted reaction solution through a 200-mesh neutral alumina column to remove copper bromide. Drop the collected solution drop by drop into an excess and rapidly stirred mixed solution of deionized water / ethanol (volume ratio 3:1), centrifuge, pour off the supernatant, collect the precipitate, wash it repeatedly many times to remove unreacted monomers, and dry the collected precipitate at 60 °C for 24 h to obtain a solid, which is the macromolecular initiator P(PFPHM9-b-DMAA)-Br.

[0073] (4) Synthesis of P(PFPHM9-b-DMAA-b-PEGMA360): Place P(PFPHM9-b-DMAA)-Br (0.3 g) prepared in step (3), copper bromide (0.025 mmol), N,N,N',N'',N''-pentamethyldiethylenetriamine (0.25 mmol), polyethylene glycol methacrylate (10 mmol), stannous octoate (0.5 mmol) and 2,2,2-trifluoroethanol (15 mL) in a container. Remove the oxygen in the reaction container by three cycles of liquid nitrogen freezing - vacuum pumping - thawing. Subsequently, fill the reaction container with high-purity nitrogen, seal it and transfer it to an oil bath at 40 - 50 °C, and react for 9 - 10 h. After the reaction is completed, cool it, dilute the reaction system with absolute ethanol. Using absolute ethanol as the eluent, pass the diluted reaction solution through a 200-mesh neutral alumina column to remove copper bromide. Drop the collected solution dropwise into an excess and rapidly stirred mixed solution of deionized water / ethanol (volume ratio 3:1), perform centrifugal separation, pour off the supernatant and collect the precipitate, wash it repeatedly many times to remove unreacted monomers, and dry the collected precipitate at 60 °C for 24 h to obtain a solid, which is the thermoresponsive amphiphilic triblock copolymer P(PFPHM9-b-DMAA-b-PEGMA360).

[0074] Example 2

[0075] In this example, a thermoresponsive amphiphilic triblock copolymer is provided. The main difference from Example 1 is that:

[0076] (1) Preparation of hydroxyethyl methacrylate perfluoropolyether acyl fluoride (PFPHM): Add hydroxyethyl methacrylate (40 mmol), 2,2,2-trifluoroethanol (50 mL) and triethylamine (40 mmol) to a reaction container and stir and mix for 10 min. Then, use a constant pressure burette to dropwise add a mixed solution of perfluoropolyether acyl fluoride and 2,2,2-trifluoroethanol. Among them, the amount of perfluoropolyether acyl fluoride added to the mixed solution is 60 mmol, and the volume of 2,2,2-trifluoroethanol is 30 mL. React at 25 - 30 °C for 8 - 10 h, extract and wash with 0.1 mol / L dilute hydrochloric acid, take the lower layer, and then extract and wash with ultrapure water many times to obtain hydroxyethyl methacrylate perfluoropolyether acyl fluoride.

[0077] Example 3

[0078] In this example, a thermoresponsive amphiphilic triblock copolymer is provided. The main difference from Example 1 is that:

[0079] (2) Synthesis of macromolecular initiator PPFPHM-Br: Add 2,2,2-trifluoroethanol (50 mL), N,N,N',N'',N''-pentamethyldiethylenetriamine (2 mmol), and copper bromide (0.2 mmol) into a reaction vessel. After ultrasonic washing for 5 min to dissolve and disperse copper bromide, add perfluoroyl fluoride polyether hydroxyethyl methacrylate (PFPHM) prepared in step (1) and ethyl 2-bromoisobutyrate into the reaction vessel. Among them, 18 mmol of perfluoroyl fluoride polyether hydroxyethyl methacrylate is added to the mixed solution, and 2 mmol of ethyl 2-bromoisobutyrate is added. After sealing and stirring for 10 - 20 min, add 2 mmol of stannous octoate, and immediately transfer the flask to a Dewar flask filled with liquid nitrogen for degassing. Remove oxygen by three cycles of liquid nitrogen freezing - vacuum pumping - thawing. Subsequently, fill the reaction vessel with high-purity nitrogen, seal it, and transfer it to an oil bath at 40 - 50 °C for reaction for 9 - 10 h. After the reaction is completed, cool it, dilute the reaction system with 30 mL of absolute ethanol, use absolute ethanol as the eluent, pass the diluted reaction solution through a 200-mesh neutral alumina column to remove copper bromide, drop the collected solution dropwise into an excessive and rapidly stirred deionized water / ethanol (volume ratio 3:1) mixed solution, perform centrifugal separation, pour off the supernatant and collect the precipitate, wash it repeatedly many times to remove unreacted monomers, and dry the collected precipitate at 60 °C for 24 h to obtain a solid, which is the macromolecular initiator PPFPHM-Br.

[0080] Example 4

[0081] This example provides a thermoresponsive amphiphilic triblock polymer drug-loaded micelle, which is prepared according to the following method:

[0082] First, dissolve DOX / HCl (3 mg) in 1 mL of acetone, and then add it to the acetone solution of P(PFPHM9-b-DMAA-b-PEGMA 360 ) in Example 1. After ultrasonic dispersion for 30 min, add 10 mL of deionized water dropwise at a rate of 10 μL / s into the rapidly stirred mixed solution of P (PFPHM9-b-DMAA-b-PEGMA 360 ), DOX / HCl, and acetone. Dialyze for 24 h and keep the dialysis process in the dark throughout. The lyophilized sample is the drug-loaded micelle.

[0083] Comparative Example 1

[0084] This comparative example provides an amphiphilic polymer dPGS-SS-PCL, which can be purchased from Xi'an Ruixi Biotechnology Co., Ltd.

[0085] Comparative Example 2

[0086] This comparative example provides an amphiphilic polymer PEG-PLA, which can be purchased from Guangzhou Carbohydrate Technology Co., Ltd.

[0087] Comparative Example 3

[0088] This comparative example provides an amphiphilic polymer PMMI-CholC6, which is prepared according to the preparation method provided in Pourmoazzen Z, Bagheri M, Entezami AA, et al. pH-responsive micelles composed of poly(ethylene glycol) and cholesterol-modified poly(monomethyl itaconate) as a nanocarrier for controlled and targeted release of piroxicam[J]. Journal of Polymer Research, 2013, 20(12).

[0089] Comparative Example 4

[0090] This comparative example provides an amphiphilic polymer PEG-b-(PDEAEMA-b-PHEMA-g-FA)2, which is prepared according to the preparation method provided in Chen Q, Zheng J, Yuan X, et al. Folic acid grafted and tertiary amino based pH-responsive pentablock polymeric micelles for targeting anticancer drug delivery[J]. Materials Science & Engineering C-Materials for Biological Applications, 2018, 82: 1-9.

[0091] Comparative Example 5

[0092] This comparative example provides an amphiphilic polymer dPGS-SS-PLA, which is prepared according to the method provided by Braatz D, Dimde M, Ma G, et al. Toolbox of Biodegradable Dendritic(Poly glycerol sulfate)-SS-poly(ester) Micelles for Cancer Treatment: Stability, Drug Release, and Tumor Targeting[J]. Biomacromolecules, 2021, 22(6): 2625-2640.

[0093] Comparative Example 6

[0094] This comparative example provides a blank micelle, which is prepared according to the following method:

[0095] Weigh 10 mg of P(PFPHM9-b-DMAA-b-PEGMA in Example 1 360 ) and dissolve it in 5 mL of acetone. Subsequently, 10 mL of deionized water was dropped into the rapidly stirred acetone solution of P (PFPHM9-b-DMAA-b-PEGMA 360 ) at a rate of 10 μL / s. Finally, the obtained polymer solution was transferred into a dialysis bag with a molecular cut-off value of 3500 and dialyzed for 24 h. Within the initial 6 h, deionized water was completely replaced every 2 h, and then deionized water was replaced every 6 h. Finally, the sample obtained by dialysis was freeze-dried using a vacuum freeze dryer to obtain the blank micelle.

[0096] Test Example 1

[0097] This test example uses fluorine nuclear magnetic resonance spectroscopy to perform nuclear magnetic characterization on HEMA, PFPHM, PPFPHM9-Br, P(PFPHM9-b-DMAA)-Br, and P(PFPHM9-b-DMAA-b-PEGMA in Example 1 360 ) respectively. The specific steps are as follows:

[0098] Using CDCl3 as the solvent for HEMA and PFPHM, DMSO-d6 as the solvent for P(PFPHM9-b-DMAA)-Br, and deuterated acetone as the solvent for PPFPHM9-Br and P(FPHM9-b-DMAA-b-PEGMA 360) , the hydrogen nuclear magnetic resonance spectra of the samples were measured at 250 MHz and 25 °C respectively.

[0099] Figure 2Respectively, HEMA and PFPHM(2a), PPFPHM9-Br (2b), P(PFPHM9-b-DMAA)-Br(2c) and P(PFPHM9-b-DMAA-b-PEGMA 360 ) in Example 1 of the present invention 1 1H NMR spectra. As can be seen from Figure 2 a, in the 1 1H NMR spectrum of HEMA, δ = 6.1 is for =CH2 of the main chain. Since =CH2 is split by the hydrogen on the adjacent carbon and becomes a doublet, the proton absorption peak of -CH2 on HEMA is at δ = 4.5, the proton absorption peak of -O-CH2 on the main chain is at δ = 3.9, the proton absorption peak of -OH hydrogen is at δ = 2.2, and the proton absorption peak of -CH3 of HMEA is at δ = 1.9. In the 1 1H NMR spectrum of PFPHM, the absorption peaks of -O-CH2 and -CH2 on the main chain shift to the left to δ = 4.7 - 4.4, and the -OH absorption peak at δ = 2.2 disappears. Thus, it can be seen that HEMA and PFPE react to form PFPHM. As can be seen from Figure 2 b, the =CH2 absorption peak disappears, and the absorption peak of -CH2 appears at δ = 1.2 - 0.9, indicating that PFPHM successfully self-polymerizes to form the macromolecular initiator PPFPHM9-Br. As can be seen from Figure 2 c, a distinct small peak appears at δ = 2.9, and this peak is the proton absorption peak of -N-CH3. The appearance of the -N-CH3 absorption peak indicates the successful synthesis of the temperature-sensitive functional macromolecular initiator P(PFPHM9-b-DMAA)-Br. As can be seen from Figure 2 d, the proton absorption peak of -OH appears at δ = 3.4, and the absorption peak of -O-CH2 appears at δ = 3.6, indicating the successful synthesis of the P(PFPHM9-b-DMAA-b-PEGMA 360 ) triblock polymer.

[0100] Test Example 2

[0101] In this test example, the HEMA, PPFPHM9-Br, P(PFPHM9-b-DMAA)-Br and P(PFPHM9-b-DMAA-b-PEGMA 360 ) of Example 1 were scanned by the KBr tablet pressing method respectively. Among them, the scanning range was 4000 - 400 cm -1 , the resolution was set to 4 cm -1 , and the number of scans was 32 times.

[0102] As Figure 3Shown are the infrared spectra of HEMA, PPFPHM9-Br, P(PFPHM9-b-DMAA)-Br, and P(PFPHM9-b-DMAA-b-PEGMA 360 ) in Example 1. From Figure 3 it can be seen that in the infrared spectrum of PPFPHM9-Br, the vibration peak at 3437 cm -1 is the -OH vibration peak of HEMA. The vibration peaks at 2941 cm -1 and 1100 - 1400 cm -1 are the vibration peaks of -CH- and the -C-F vibration peak of perfluoropolyether acyl fluoride, respectively. The vibration absorption peak at 500 - 750 cm -1 is the in-plane rocking vibration absorption peak of CF3-CF2-, indicating the successful synthesis of PPFPHM9-Br. In the infrared spectrum of P(PFPHM9-b-DMAA)-Br, the bending vibration at 1634 cm -1 is for -C-N-, indicating the successful synthesis of P(PFPHM9-b-DMAA)-Br. The vibration at 1110 cm -1 is the -C-O- vibration of polyethylene glycol methacrylate, indicating the successful synthesis of P(PFPHM9-b-DMAA-b-PEGMA 360 ).

[0103] Test Example 3

[0104] This test example conducts a lower critical solution temperature (LCST) test on P(FPHM9-b-DMAA-b-PEGMA 360 ) in Example 1. The specific steps are as follows:

[0105] First, prepare an aqueous solution of P(FPHM9-b-DMAA-b-PEGMA 360 ) with a concentration of 1 mg / mL and measure the transmittance of this solution. Then, measure the transmittance of the solution under the heating conditions of a wavelength of 510 nm and a heating rate of 1 °C / min respectively.

[0106] As Figure 4 shown is the transmittance change curve of P(FPHM9-b-DMAA-b-PEGMA 360 ) in Example 1. Among them, the temperature at which the transmittance reaches 50% of the total transmittance is the LCST. From Figure 4 it can be seen that as the temperature increases, the transmittance of the sample solution begins to decrease and stabilizes at 45 °C. When the temperature rises to 39 °C, the transmittance decreases to 50%. Therefore, the LCST of P(FPHM9-b-DMAA-b-PEGMA 360 ) is 39 °C.

[0107] Test Example 4

[0108] In this test example, pyrene was used as a probe to determine the CMC value of the thermoresponsive amphiphilic triblock polymer P(FPHM9-b-DMAA-b-PEGMA 360 ) in Example 1. The specific steps are as follows:

[0109] P(FPHM9-b-DMAA-b-PEGMA 360 ) was respectively configured into a series of concentrations of 5×10 -1 ~1×10 -4 mg / mL. Then, 24 mg of pyrene was weighed and dissolved in 100 mL of methanol to prepare a methanol solution of pyrene with a concentration of 1.2×10 -3 mol / L for later use. Then, 1 mL of the pyrene methanol solution was taken and diluted to a molar concentration of 1.2×10 -5 mol / L with 99 mL of methanol and sealed for storage. Then, 0.5 mL of the pyrene methanol solution was placed in corresponding 10-mL sample bottles and left for 24 h to allow the methanol to evaporate. Finally, 10 mL of polymer solutions with different concentrations were added to the sample bottles containing pyrene, ultrasonicated for 1 h, and left in the dark to equilibrate for 24 h before testing. Among them, the concentration of pyrene in the sample solution was 6×10 -7 mol / L. The test parameters were set as follows: the emission wavelength was 373 nm, and the mixed solution was scanned in the wavelength range of 300 - 350 nm.

[0110] As Figure 5 shown is the relationship diagram between the fluorescence intensity and wavelength of P(PFPHM9-b-DMAA-b-PEGMA 360 ) in Example 1 of the present invention. From Figure 5 it can be seen that as the concentration of P(PFPHM9-b-DMAA-b-PEGMA 360 ) increases, the fluorescence intensity of pyrene continuously increases and the third peak undergoes a chemical shift, gradually red-shifting from 336.1 nm to 338.4 nm. This indicates that pyrene changes from a hydrophilic environment to a hydrophobic environment.

[0111] As Figure 6 shown is the relationship diagram between I338.4 / I336.1 and the logarithm of the concentration of P(PFPHM9-b-DMAA-b-PEGMA Figure 5 ), with the ratio of I336.1 and I338.4 in 360 as the ordinate and the logarithm of the concentration of P(PFPHM9-b-DMAA-b-PEGMA 360 ) as the abscissa. From Figure 6 it can be seen that the turning point where I338.4 / I336.1 increases sharply is the CMC value of the polymer. The calculated CMC value of P(PFPHM9-b-DMAA-b-PEGMA 360) The CMC value is 1.0 μg / L.

[0112] Test Example 5

[0113] As Figure 7 shown is the comparison chart of the CMC of P(PFPHM9-b-DMAA-b-PEGMA 360 ) of Example 1 of the present invention and the amphiphilic polymers of Comparative Examples 1-5. From Figure 7 it can be seen that the CMC value of the fluorocarbon chain-containing amphiphilic polymer is much lower than that of the conventional carbon chain amphiphilic polymer. And P(PFPHM9-b-DMAA-bPEGMA 360 ) has a lower critical micelle concentration, indicating that the core-shell structure of its aqueous solution is relatively stable. Even at a lower concentration, it can maintain a complete structure, which is beneficial to prolong its circulation time in the human body.

[0114] Example 6

[0115] Weigh 5 mg of the blank micelles of Comparative Example 6 and 5 mg of the drug-loaded micelles of Example 4 respectively, add 5 mL of absolute ethanol to each and disperse them evenly by ultrasonic treatment, then add deionized water to dilute 100 times, and use a Malvern nano particle size analyzer to measure the particle size of the samples respectively. Each sample is tested three times repeatedly to obtain the average particle size. Among them, the measurement conditions are: measure the particle size of the micelles with a He-Ne laser beam at 25 °C and 633 nm. Use dynamic light scattering to test the size and its distribution range of the P(PFPHM9-b-DMAA-b-PEGMA 360 ) assembled micelles.

[0116] As Figure 8 shown is the particle size distribution chart of the blank micelles of Comparative Example 6 and the drug-loaded micelles of Example 4. From Figure 8 it can be seen that for P(PFPHM9-b-DMAA-b-PEGMA 360 ), the particle size of the micelles before drug loading is about 90 nm. After loading doxorubicin (DOX), its particle size increases significantly. The average particle size of the drug-loaded micelles is about 220 nm.

[0117] As Figure 9 shown is the TEM image of the drug-loaded micelles of Example 4 and the blank micelles of Comparative Example 6. Among them, Figure 9 a and 9b are the TEM images of the drug-loaded micelles, Figure 9 c is the TEM image of the blank micelles. From Figure 9 it can be seen that the darker color part in the core of the micelles is the loaded DOX. Comparing the particle sizes before and after drug loading, the particle size of the drug-loaded micelles increases significantly, indicating that a certain amount of DOX can be encapsulated in the cavity of the micelles.

[0118] Example 7

[0119] Drug loading and encapsulation efficiency test:

[0120] Calculate the drug loading of the micelles according to formula (1)

[0121]

[0122] Where: m1 is the mass of the drug loaded in the polymeric micelles, mg; m2 is the total mass of the drug-loaded micelles, mg;

[0123] Calculate the encapsulation efficiency of the micelles according to formula (2)

[0124]

[0125] Where: m1 is the mass of the drug loaded in the polymeric micelles, mg; m3 is the mass of the drug input, mg;

[0126] Prepare blank micelles and drug-loaded micelles of P(PFPHM9-b-DMAA-b-PEGMA 360 ) by dialysis method. Then, calculate according to formula (1) and formula (2) respectively, and it is known that the drug loading of P(PFPHM9-b-DMAA-b-PEGMA 360 ) is 20.6%, and the encapsulation efficiency is 86.6%, indicating that the polymeric micelles can effectively encapsulate DOX, as shown in Table 1 specifically:

[0127] Table 1 Analysis of drug loading and encapsulation efficiency of drug-loaded micelles

[0128]

[0129] Test Example 8

[0130] This test example is for the drug release rate test of the drug-loaded micelles in Example 4. The specific steps are as follows:

[0131] Prepare a series of DOX / ethanol solutions with concentrations of 1, 0.75, 0.5, 0.25, 0.1, 0.075, 0.05, 0.025, 0.01 mg·mL -1 respectively. Then, detect the absorbance at 495 nm with a UV spectrophotometer and draw the standard curve of doxorubicin / ethanol.

[0132] The freeze-dried drug-loaded micelle samples were dissolved in 10 mL of absolute ethanol and then transferred into a dialysis bag with a molecular weight cut-off value of 3500. 200 mL of phosphate buffer solution with pH = 6.5 was added, and dialysis was carried out at 37 °C and 42 °C respectively. Then, 3 mL of samples were taken at 1, 2, 4, 8, 12, 24, 48, and 72 h respectively, and 3 mL of fresh medium was supplemented. The whole process was carried out under dark conditions. Using the standard curve of doxorubicin / ethanol, the absorbance of different samples was measured by an ultraviolet spectrophotometer, the concentration of DOX was calculated, and the cumulative drug release rate (Er) was calculated using the following formula (3);

[0133]

[0134] In the formula: mDOX represents the mass of DOX in the micelles, mg; V0 is the volume of the release medium, mL; Cn represents the concentration of DOX in the nth sample, mg / mL.

[0135] As Figure 10 shown is the in vitro simulated release diagram of the P(PFPHM9-b-DMAA-b-PEGMA 360 ) drug-loaded micelles of Example 4 at 37 °C. Figure 11 is the in vitro simulated release diagram of the P(PFPHM9-b-DMAA-b-PEGMA 360 ) drug-loaded micelles of Example 4 at 42 °C. Among them, Figure 10 and 11 are the rate diagrams of DOX in vitro release calculated at different times through formula (3). 37 °C simulates the human body temperature, and 42 °C simulates the temperature of cancerous tissues. From Figure 10 and Figure 11 , it can be observed that as the release time increases, the absorbance of DOX increases, and the release rate of DOX at 42 °C is significantly faster than that at 37 °C. The drug release amount at 72 h reaches 94.7%. While at 37 °C, the release rate at 72 hours is only 33.1%. This is because a clear-turbid phase transition occurs in the aqueous solution before and after the LCST. When the temperature is lower than the LCST, there is a hydrogen bond interaction between the amide group and water molecules. When the temperature is higher than the LCST, the hydrogen bond interaction weakens or breaks, and the polymer chains entangle with each other, making DOX easier to release, and its hydrophilic-hydrophobic property, volume, micelle structure, etc. will all change significantly. Therefore, the release rate at 42 °C is significantly faster than that at 37 °C.

[0136] At 37 °C, due to the slow release of the drug, it is beneficial for the drug to circulate in the body, reduce the dosage of the drug, and reduce the side effects of the drug on the human body. While at 42 °C, the drug is released rapidly, which is beneficial for acting on the patient's position in a short time and reducing the treatment time.

[0137] Test Example 9

[0138] In this test example, the MTT colorimetric method was used to conduct biotoxicity tests on DOX, the drug-loaded micelles of Example 4, and the blank micelles of Comparative Example 6. The specific steps are as follows:

[0139] HepG2 cells were cultured in a saturated humidity incubator at 37°C and 5% CO2, and the culture medium was DMEM. Among them, Dulbecco’s Modified Eagle Medium (DMEM) culture medium was purchased from Wuhan Punosai Life Science Co., Ltd.; the liver cancer cell line HepG2 was purchased from the Shanghai Institute of Cell Biology, Chinese Academy of Sciences. Then, in a 96-well plate, 5×10 3 cells were seeded at 180 μL per well, and then a series of concentrations of DOX, P(FPHM9-b-DMAA-b-PEGMA 360 )-DOX, and P(FPHM9-b-DMAA-b-PEGMA 360 ) were used to culture the cells at 37°C for 48 h. Then, 20 μL of MTT solution (5 mg / mL) was added and cultured for 4 h, and then all the solutions were removed. 150 μL of DMSO was added to each well to dissolve the formed formazan crystals, and the absorbance value at 490 nm was measured after oscillating in a constant temperature water bath shaker (37°C, 100 rpm) for 10 min. The cell growth inhibition rate was calculated using formula (4).

[0140]

[0141] As Figure 12 shown is the cell growth inhibition rate curve of doxorubicin, P(PFPHM9-b-DMAA-b-PEGMA 360 ) of Comparative Example 6, and P(PFPHM9-b-DMAA-b-PEGMA 360 )-DOX of Example 4 on HepG2 cells. From Figure 12 it can be seen that the blank micelles have no biotoxicity. Since the drug-loaded micelles need time to release DOX, the biotoxicity of DOX is higher than that of the drug-loaded micelles.

[0142] The embodiments described above are some embodiments of the present invention, rather than all embodiments. The detailed description of the embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely represents the selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

Claims

1. A method for preparing a thermoresponsive amphiphilic triblock polymer, characterized in that, It includes the following steps: S1. React perfluoropolyether acyl fluoride CF3CF2CF2OCF(CF3)CF(O) with 2-hydroxyethyl methacrylate to obtain perfluoropolyether acyl fluoride 2-hydroxyethyl methacrylate containing an olefin structure. Specifically, the 2-hydroxyethyl methacrylate, 2,2,2-trifluoroethanol and triethylamine are placed in a first reaction vessel and stirred and mixed, and then a mixed solution of the perfluoropolyether acyl fluoride and 2,2,2-trifluoroethanol is added dropwise under constant pressure. After reacting at 25~30°C for 8~10 h, it is extracted and washed with dilute hydrochloric acid, the lower layer is taken and extracted and washed with ultrapure water for multiple times to obtain the perfluoropolyether acyl fluoride 2-hydroxyethyl methacrylate. S2. Use ethyl 2-bromoisobutyrate to initiate the self-polymerization of the perfluoropolyether acyl fluoride 2-hydroxyethyl methacrylate and introduce a terminal bromine atom to obtain a macroinitiator PPFPHM-Br. S3. Introduce a thermoresponsive functional monomer N,N-dimethylacrylamide DMAA into the macroinitiator PPFPHM-Br to obtain P(PFPHM9-b-DMAA)-Br. S4. Introduce the hydrophilic chain segment of poly(ethylene glycol) methacrylate using the P(PFPHM9-b-DMAA)-Br as a thermoresponsive macroinitiator 360 PEGMA 360 , and obtain a thermoresponsive amphiphilic triblock polymer P(PFPHM9-b-DMAA-b-PEGMA 360 ).

2. The preparation method according to claim 1, characterized in that, In step S1, the molar ratio of the perfluoropolyether acyl fluoride to the 2-hydroxyethyl methacrylate is 1.5~2:

1.

3. The preparation method according to claim 1, wherein, In step S2, the specific steps for synthesizing the macroinitiator PPFPHM-Br include: S21. Place 2,2,2-trifluoroethanol, N,N,N',N'',N''-pentamethyldiethylenetriamine and copper bromide in a second reaction vessel. After ultrasonic washing, add the perfluoropolyether acyl fluoride 2-hydroxyethyl methacrylate and ethyl 2-bromoisobutyrate, seal and stir for 10~20 min, then add stannous octoate, and degas the second reaction vessel with liquid nitrogen. S22. Fill the second reaction vessel with high-purity nitrogen, seal it and transfer it to an oil bath at 40~50°C for reaction for 9~10 h. Cool and dilute the reaction system with anhydrous ethanol to obtain a first reaction solution. S23. Using anhydrous ethanol as an eluent, pass the first reaction solution through a neutral alumina column with a mesh size of 180~220, and then dropwise add it into an excessive and rapidly stirred deionized water / ethanol mixed solution. After centrifugation, washing and drying, the macroinitiator PPFPHM-Br is obtained.

4. The preparation method according to claim 1, wherein, The specific steps for introducing the thermoresponsive functional monomer DMAA into the macroinitiator PPFPHM-Br include: S31. Place the macroinitiator PPFPHM-Br, copper bromide, N,N,N',N'',N''-pentamethyldiethylenetriamine, N,N-dimethylacrylamide, stannous octoate and 2,2,2-trifluoroethanol in a third reaction vessel, and degas the reactor with liquid nitrogen. S32. Fill the third reaction vessel with high-purity nitrogen, seal it and transfer it to an oil bath at 40~50°C for reaction for 9~10 h. Cool and dilute the reaction system with anhydrous ethanol to obtain a second reaction solution. S33. Using absolute ethanol as the eluent, pass the second reaction solution through a neutral alumina column with a mesh size of 180 - 220, and then dropwise add it into an excessive and rapidly stirred deionized water / ethanol mixed solution. After centrifugation, washing, and drying, the macromolecular initiator P(PFPHM9 - b - DMAA)-Br is obtained.

5. The preparation method according to claim 1, characterized in that, Introduce the hydrophilic chain segment PEGMA using the P(PFPHM9-b-DMAA)-Br as a thermoresponsive macroinitiator 360 The specific steps include: S41. Place the P(PFPHM9 - b - DMAA)-Br, copper bromide, N,N,N',N'',N'' - pentamethyldiethylenetriamine, polyethylene glycol methacrylate, stannous octoate, and 2,2,2 - trifluoroethanol in a fourth reaction vessel, and degas the fourth reaction vessel with liquid nitrogen. S42. Fill the fourth reaction vessel with high - purity nitrogen, seal it, and transfer it to an oil bath at 40 - 50 °C for reaction for 9 - 10 h. Cool and dilute the reaction system with absolute ethanol to obtain a third reaction solution. S43. Using absolute ethanol as the eluent, passing the third reaction solution through a neutral alumina column with a mesh size of 180 - 220, and then dropwise adding it into an excessive and rapidly stirred deionized water / ethanol mixed solution. After centrifugation, washing, and drying, a thermoresponsive amphiphilic triblock copolymer P(PFPHM9-b-DMAA-b-PEGMA 360 ) is obtained.

6. An amphiphilic triblock polymer with thermal responsiveness, characterized in that, Prepared according to the preparation method described in any one of claims 1 - 5.

7. Use of the amphiphilic triblock polymer with thermoresponsive properties as described in claim 6 in the preparation of doxorubicin drugs with drug - slow - release function.

8. A preparation method of a thermoresponsive amphiphilic triblock polymer drug-loaded micelle, characterized in that, Comprising the following steps: Dissolve doxorubicin hydrochloride in an acetone solution, and then add the thermoresponsive amphiphilic triblock polymer P(PFPHM9-b-DMAA-b-PEGMA 360 ) as described in claim 6 to the acetone solution. After ultrasonic dispersion, it is dropped into deionized water, dialyzed in the dark for 24 - 30 h, and then freeze-dried to obtain a thermoresponsive amphiphilic triblock polymer drug-loaded micelle.

9. A thermoresponsive amphiphilic triblock polymer drug-loaded micelle, characterized in that, Prepared according to the preparation method described in claim 8.

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