Functionalized polyethyleneimine with stimulus responsiveness and preparation method thereof

Abstract

The invention discloses a functionalized polyethyleneimine with stimulus responsiveness and a preparation method thereof, wherein the preparation method comprises the following steps: S1. reacting polyethyleneimine, a monomer W-F containing a functional group and an excess of a substituted or unsubstituted lactone compound in a solvent under a protective atmosphere, so that the functional group on the monomer is grafted onto the polyethyleneimine; S2. oxidative coupling reaction of the grafted polyethyleneimine occurs under an oxidative atmosphere or oxidation by an oxidant to obtain the functionalized polyethyleneimine. The preparation method of the functionalized polyethyleneimine with stimulus responsiveness of the invention is gentle and efficient, has no external catalyst, is easy to purify, has high atomic utilization, has adjustable components, and is convenient for mass synthesis.

Description

Technical Field

[0001] The invention relates to the technical field of functionalized polyethyleneimine materials, and in particular to a functionalized polyethyleneimine with stimulus responsiveness and a preparation method thereof. Background Art

[0002] Polyethyleneimine (PEI) is one of the most studied cationic polymer gene transfection vectors due to its high charge density and good proton buffering capacity. However, there is a relationship between cytotoxicity and transfection efficiency of PEI that has not been chemically modified. High molecular weight PEI has a higher transfection efficiency, but greater cytotoxicity, while low molecular weight PEI has lower cytotoxicity but can hardly mediate gene transfection. Therefore, many researchers are committed to the structural modification of PEI to improve its transfection efficiency. A variety of molecular groups are often used to modify PEI to reduce its cytotoxic effects and enhance the in vivo and in vitro stability of PEI and gene complexes, including PEG, polysaccharides, linear alkanes, cholesterol, fluorinated groups, etc. In addition, good stability during delivery and effective dissociation of intracellular genes are a common contradiction in the design of gene delivery systems.

[0003] In view of this, researchers have used disulfide bonds, diselenide bonds and other redox stimulus responsive groups to couple low molecular weight PEI, so that it has the characteristics of high molecular weight PEI outside the cell and degrades into low molecular weight PEI in the intracellular microenvironment, thereby reducing cytotoxic effects.

[0004] Wang et al. introduced PEG and disulfide / selenium groups on the carrier to reduce the cytotoxicity of PEI polymers. He first prepared disulfide / selenopropionic acid, then reacted one end with PEG with an amino terminal, and the other end with the amino group of PEI. The entire reaction has more than three steps and it is impossible to ensure that the carboxyl group reacts with the two types of amino groups in sequence (J. Mater. Chem. B, 2013, 1, 6418-6426). Hourigan et al. first introduced carboxyl groups by reacting their specially prepared disulfide dipropionic anhydride with ethylene glycol chitosan, and then esterified it with low molecular weight PEI to prepare a branched PEI carrier with a reduction-responsive disulfide bond structural unit, thereby obtaining a high molecular weight PEI that reduces the cytotoxicity of the carrier and improves the in vitro transfection effect (Carbohydr. Polym., 2016, 153, 160-168). Klibanov and Thomas et al. of MIT respectively reacted bPEI 25k and bPEI 2k After hydrophobic modification, it was found that bPEI modified with alanine 25k The toxicity was reduced, and the transfection activity in the presence of serum was nearly doubled. 2k The transfection activity of bPEI in the presence of serum is2k 400 times that of bPEI 25k 6 times of that of (Proc.Natl.Acad.Sci.USA,2002,99,14640-14645). Kim et al. found that hydrophobic modification of low molecular weight PEI with groups such as cholesterol can reduce its toxicity and enhance its transfection activity (Carcinogenesis,2001,22,1069-1076). Yin et al. used a specially prepared diselenide-containing double-headed acrylate to couple low molecular weight polyethyleneimine, and then fluorinated it in one step to synthesize high molecular weight DSe-PEI. Fluorine modification enhanced its serum stability, and combined with the stimulus-responsive cleavage of the diselenide bond, it effectively increased the cellular uptake and ensured its efficient gene transfection efficiency in serum (Biomater.Sci.,2017,5,1174-1182).

[0005] However, the above-mentioned prior art still has the following major disadvantages: the modification of functional groups and disulfide / selenium bonds effectively improves the transfection efficiency and cytotoxicity of various gene vectors. However, these vectors face multi-step reactions in the preparation process and require complex purification, resulting in low reaction efficiency, small synthesis scale and low yield. Usually, only a single functional group can be modified, and there is a lack of a universal synthesis platform. These have limited the research and application development of functionalized polyethyleneimine. Summary of the invention

[0006] The present invention successfully prepares a functionalized polyethyleneimine with stimulus responsiveness based on a multi-component reaction of selenium (thiol) click chemistry. The method of the present invention is mild and efficient, has no external catalyst, is easy to purify, has 100% atomic utilization, has adjustable components, is easy to combine and screen, and is synthesized on a large scale.

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0008] The present invention provides a method for preparing a functionalized polyethyleneimine having stimulus responsiveness, comprising the following steps:

[0009] S1. Under a protective atmosphere, polyethyleneimine, a monomer WF containing a functional group and an excess of a substituted or unsubstituted lactone compound are reacted in a solvent so that the functional group on the monomer is grafted onto the polyethyleneimine;

[0010] S2. In an oxidizing atmosphere or an oxidizing agent, the grafted polyethyleneimine undergoes an oxidative coupling reaction to obtain the functionalized polyethyleneimine;

[0011] Wherein, the lactone compound is thiolactone and / or selenolactone;

[0012] The monomer containing a functional group is W-F, where W is a halogenated hydrocarbon, an acyl halide, or a conjugated compound containing a carbon-carbon double bond / triple bond, and F is a functional group;

[0013] Among them, the lactone compound is a thiolactone and / or a selenolactone;

[0014] The monomer containing a functional group is W-F, where W is a halogenated hydrocarbon, an acyl halide, or a conjugated compound containing a carbon-carbon double bond / triple bond, and F is a functional group.

[0015] The reaction principle of the present invention is as follows:

[0016] In step S1, due to the relatively weak C-Se(S) bond in the thiolactone / selenolactone, a general nucleophilic group, such as an amino group, can undergo nucleophilic substitution with it under the condition of no catalyst to generate an amide intermediate with a thiol / selenol end group. The thiol / selenol can further undergo an efficient Michael substitution or addition reaction with the halogen or conjugated double / triple bond on the functional compound, thereby grafting the functional group onto the polyethyleneimine.

[0017] In step S2, under the oxidation of an oxidative atmosphere or an oxidant, the thiol / selenol groups on the polyethyleneimine will undergo a sulfur-sulfur / selenium-selenium oxidative coupling reaction to finally obtain polyethyleneimine coupled with disulfide / diselene bonds.

[0018] The reaction roadmap of the above reaction is shown as follows:

[0019]

[0020] In step S1, the structural formula of the lactone compound is Among them, X = S or Se, 0 < m < 8, and m is an integer; Y is selected from H, OH, NH2, ether group (-OR), ester group (-COOR), acid anhydride (-COOCOR), amide (-CONH2), imine (-N=CR 1 R 2 )), oxime (-RC=NOH), hydrazine (-NH-NH2). Among them, the above alkyl group includes a straight-chain alkyl group or a branched-chain alkyl group, and the carbon chain length of the alkyl group is not limited. For example, it can be 1-8; the types of substituents are not limited. For example, they can be halogens (F, Cl, Br, I). The above substituents R, R 1 , R 2 can be the same or different. For example, they can be substituted or unsubstituted alkyl groups, halogens, etc. with 1-6 carbon atoms.

[0021] In step S1, the functional groups include, but are not limited to, one or more of the following groups: (1) groups with biocompatibility; (2) groups with anti-protein / anti-serum functions; (3) tracer / detection groups with ultraviolet absorption, fluorescence emission or radioactivity functions; (4) other functional groups with various functions. As an illustrative embodiment, the functional groups may include one or more of cholesterol groups, phosphorylcholine groups, polyethylene glycol groups, chitosan groups, cellulose groups, and fluoride groups.

[0022] Further, in step S1, the thiolactone is selected from One or more of; the selenolactone is selected from One or more of .

[0023] Furthermore, in step S1, in the monomer WF containing a functional group, W is a (meth)acrylate monomer, and the functional group F includes but is not limited to a polyethylene glycol segment, a fluorine-containing group, a positive and negative ion group, a cholesterol group, and a tetraphenylethylene group. In a preferred embodiment, the monomer WF containing a functional group is selected from

[0024] One or more of .

[0025] Furthermore, in step S1, the protective atmosphere includes at least one of a nitrogen atmosphere and an inert atmosphere, preferably a nitrogen atmosphere or an argon atmosphere.

[0026] Furthermore, in step S1, the solvent is water and / or an organic solvent, and the organic solvent may be selected from conventional organic solvents in the art, including but not limited to methanol, ethanol, acetone, and the like.

[0027] Furthermore, in step S1, the polyethyleneimine (PEI n ) can be linear polyethyleneimine or branched polyethyleneimine. n 1≤n<50, that is, the molecular weight of PEI is preferably 500-25000, for example, it can be 500, 1000, 5000, 10000, 15000, 20000, 25000, etc.

[0028] Furthermore, in step S1, the molar ratio of the amino group to the lactone compound in the polyethyleneimine is 100:1 to 100, for example, 100:1, 50:1, 30:1, 20:1, 10:1, 5:1, 2:1, 1:1, etc.

[0029] Furthermore, in step S1, the molar ratio of the thiolactone / selenolactone to the functional group in the monomer WF containing the functional group is 1:0.1-1, for example, it can be 1:0.1, 1:0.2, 1:0.3, 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, etc.

[0030] Furthermore, in step S1, the reaction time is 5-500 min, for example, it can be 5 min, 10 min, 20 min, 30 min, 50 min, 100 min, 120 min, 200 min, 300 min, 400 min, 500 min, etc.

[0031] Furthermore, in step S2, the oxidizing atmosphere may be various atmospheres having an oxidizing function, including an oxygen atmosphere, an air atmosphere, and the like.

[0032] Furthermore, in step S2, the oxidation time is 1-24 h, for example, it can be 1 h, 2 h, 4 h, 6 h, 8 h, 10 h, 12 h, 16 h, 20 h, 24 h, etc.

[0033] The invention also provides a functionalized polyethyleneimine with stimulus responsiveness prepared by the method.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] 1. The present invention utilizes the Michael addition reaction of selenium (thiol) alcohol and double bonds and the oxidative coupling reaction of selenium (thiol) alcohol itself to synthesize functionalized polyethyleneimine with stimulus responsiveness. Compared with the traditional method, the reaction of the present invention has the advantages of being mild and efficient, requiring no external catalyst, being easy to purify, achieving 100% atomic utilization, having adjustable components, and being convenient for large-scale synthesis.

[0036] 2. The stimuli-responsive functionalized polyethyleneimine prepared by the present invention can be used as a vector for gene transfection. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 The polyethylene glycol-grafted diselenide bond coupled polyethyleneimine PEI-Se-PEG in Example 1 of the present invention 1 HNMR spectrum;

[0038] Figure 2 The present invention is Example 1, different coupling density polyethylene glycol grafted diselenide bond coupling polyethyleneimine PEI-Se-PEG 1 H NMR spectrum;

[0039] Figure 3The fluorine-grafted diselenide bond coupled polyethyleneimine PEI-Se-F in Example 2 of the present invention 1 H NMR spectrum;

[0040] Figure 4 The zwitterion-grafted diselenide bond-coupled polyethyleneimine PEI-Se-MPC in Example 3 of the present invention is 1 HNMR spectrum;

[0041] Figure 5 The cholesterol-grafted diselenide bond coupled polyethyleneimine PEI-Se-Chol in Example 4 of the present invention is 1 HNMR spectrum;

[0042] Figure 6 The tetraphenylethylene grafted diselenide bond coupled polyethyleneimine PEI-Se-TPE in Example 5 of the present invention is 1 HNMR spectrum;

[0043] Figure 7 is the XPS spectrum of P2 after oxidation;

[0044] Figure 8 It is the oxidation of P2 1 H NMR spectrum;

[0045] Fig. 9 is the agarose gel electrophoresis retardation diagram of P2-5 at different N / P ratios;

[0046] Fig.10 is the agarose gel electrophoresis retardation diagram of P2-5 after oxidation;

[0047] Fig.11 The cytotoxicity of P2-5 and PEI 25kDa to huh-7 cells. DETAILED DESCRIPTION

[0048] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it, but the embodiments are not intended to limit the present invention.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0050] In the following examples of the present invention, the purity and sources of the reagents used are as follows:

[0051] Polyethyleneimine, M n 600(PEI 600 ), Aladdin, 99%; Polyethylene glycol methyl ether methacrylate, M n 500(PEGMA 500 ), Anage Chemical; perfluorohexylethyl methacrylate (13FMA), Anage Chemical, 97%; 2-methacryloyloxyethyl phosphorylcholine (MPC), J&K, 96%; cholesteryl methacrylate (CholMA), homemade in the laboratory; tetraphenylethylene acrylate (TPEA), homemade in the laboratory; selenolide (SBL), homemade in the laboratory; chloroform, Jiangsu Qiangsheng Functional Chemical Co., Ltd., analytical grade; anhydrous methanol, Jiangsu Qiangsheng Functional Chemical Co., Ltd., analytical grade; ether, Jiangsu Qiangsheng Functional Chemical Co., Ltd., analytical grade; deionized water, specified grade.

[0052] In the following embodiments of the present invention, the test instruments and test methods used are as follows:

[0053] H NMR spectrum ( 1 H NMR was measured by Bruker 300MHz NMR, and the sample was dissolved in deuterated water (D2O), deuterated methanol (CD3OD) or deuterated chloroform (CDCl3) as solvent and tetramethylsilane (TMS) as internal standard. X-ray photoelectron spectroscopy (XPS) was measured on an X-ray photoelectron spectrometer (ThermoFisher Scientific ESCALAB 250 XI, Al KR source).

[0054] Example 1: Preparation of polyethylene glycol-grafted diselenide bond-coupled polyethyleneimine

[0055] Take PEI 600 (1mmol), PEGMA 500 (1mmol) was dissolved in 2mL deionized water, oxygen was removed by argon, SBL (2mmol) was injected by syringe differential weight method, and the degree of reaction of selenolactone and double bond was monitored by NMR after stirring at room temperature for 10min. After the reaction was completed, it was stirred at room temperature for 12h under open air atmosphere, and the solvent was removed by freeze drying to obtain a yellow viscous solid. In addition, polyethyleneimine PEI-Se-PEG with different coupling densities was prepared by adding different amounts of SBL, and the samples were named P2, P3, P4, and P5 according to the amount of SBL added.

[0056] Figure 1-2 It is a polyethylene glycol-grafted diselenide bond coupled with polyethyleneimine 1 H NMR spectrum (D2O as solvent). As can be seen from the figure, PEI 600 PEGMA 500The three components of SBL reacted completely and the target product PEI-Se-PEG was successfully synthesized.

[0057] Example 2: Preparation of fluorine-grafted diselenide bond-coupled polyethyleneimine

[0058] Take PEI 600 (1mmol) and 13FMA (1mmol) were dissolved in 2mL of anhydrous methanol, and oxygen was removed by passing argon. SBL (4mmol) was injected by syringe differential weight method. After stirring at room temperature for 10min, the degree of reaction of selenolactone and double bond was monitored by NMR. After the reaction was completed, the mixture was stirred at room temperature for 12h in an open air atmosphere, and the solvent was removed by ether precipitation. The mixture was dried in vacuo at 40°C to constant weight to obtain a yellow viscous solid PEI-Se-F.

[0059] Figure 3 It is a fluorine-grafted diselenide bond coupled polyethyleneimine 1 H NMR spectrum (CD3OD as solvent). It can be seen from the figure that the target product PEI-Se-F was successfully synthesized.

[0060] Example 3: Preparation of zwitterion-grafted diselenide bond-coupled polyethyleneimine

[0061] Take PEI 600 (1mmol) and MPC (1mmol) were dissolved in 2mL deionized water, and argon was passed to remove oxygen. SBL (4mmol) was injected by syringe differential weight method. After stirring at room temperature for 10min, the degree of reaction of selenolactone and double bond was monitored by NMR. After the reaction was completed, the mixture was stirred at room temperature for 12h under open air atmosphere, and the solvent was removed by freeze drying to obtain a yellow viscous solid PEI-Se-MPC.

[0062] Figure 4 It is a zwitterion-grafted diselenide bond coupled to polyethyleneimine 1 H NMR spectrum (D2O as solvent). It can be seen from the figure that the target product PEI-Se-MPC was successfully synthesized.

[0063] Example 4: Preparation of cholesterol-grafted diselenide-coupled polyethyleneimine

[0064] Take PEI 600 (1mmol) and CholMA (1mmol) were dissolved in a mixed solvent of 1mL chloroform and 1mL anhydrous methanol, and argon was passed to remove oxygen. SBL (4mmol) was injected by syringe differential weight method. After stirring at room temperature for 20min, the degree of reaction of selenolactone and double bond was monitored by NMR. After the reaction was completed, the mixture was stirred at room temperature for 12h in an open air atmosphere, and the solvent was removed by ether precipitation. The mixture was dried in vacuo at 40°C to constant weight to obtain a yellow viscous solid PEI-Se-Chol.

[0065] Figure 5 It is a cholesterol-grafted diselenide bond coupled to a low molecular weight polyethyleneimine 1 H NMR spectrum (CD3OD as solvent). As can be seen from the figure, the target product PEI-Se-Chol was successfully synthesized.

[0066] Example 5: Preparation of tetraphenylethylene grafted diselenide bond coupled low molecular weight polyethyleneimine

[0067] Take PEI 600 (1mmol) and TPEA (0.1mmol) were dissolved in a mixed solvent of 1mL chloroform and 1mL anhydrous methanol, and argon was passed to remove oxygen. SBL (4mmol) was injected by syringe differential weight method. After stirring at room temperature for 20min, the degree of reaction of selenolactone and double bond was monitored by NMR. After the reaction was completed, the mixture was stirred at room temperature for 12h under open air atmosphere, and the solvent was removed by ether precipitation. The mixture was dried in vacuo at 40°C to constant weight to obtain a yellow viscous solid PEI-Se-TPE.

[0068] Figure 6 It is a tetraphenylethylene grafted diselenide bond coupled with low molecular weight polyethyleneimine 1 H NMR spectrum (CD3OD as solvent). It can be seen from the figure that the target product PEI-Se-TPE was successfully synthesized.

[0069] Performance Testing

[0070] 1. Oxidative responsiveness of functionalized polyethyleneimine

[0071] 10 mg of P2 was weighed and dissolved in 0.05% H2O2 aqueous solution, kept at 37°C for 1 hour and then freeze-dried. The freeze-dried sample was subjected to XPS and 1 H NMR analysis.

[0072] Figure 7-8 They are the XPS spectra of the oxidized polymer P2 and 1 H NMR spectrum.

[0073] 2. Agarose gel electrophoresis blocking experiment of functionalized polyethyleneimine

[0074] According to different N / P ratios, polymer P2-5 solution was added to siRNA solution (1 μg of siRNA was taken), and the volume of each solution was filled to 30 μL with DEPC water. The mixture was gently pipetted and mixed. After vortexing for 5 seconds, the solution on the wall was aspirated to the bottom of the ep tube, and incubated at 37°C for 30 minutes to condense siRNA and form a polymer / siRNA complex. The positive control vector used commercial reagent PEI 25kDa, and the negative control was free siRNA. After incubation, agarose gel electrophoresis was performed at 90V for 25 minutes, and the results were observed with a gel imager. The ROS responsiveness of the complex was observed by electrophoresis after incubation at a concentration of 0.05% H2O2 for 30 minutes, and then the results were observed by a gel imager.

[0075] Fig. 9 This is the agarose gel electrophoresis retardation diagram of P2-5 at different N / P ratios. Fig.10 This is the agarose gel electrophoresis retardation diagram of P2-5 after oxidation. It can be seen from the figure that PEI-Se-PEG can achieve effective retardation and controllable release under oxidative conditions.

[0076] 3. Cytotoxicity of functionalized polyethyleneimine, the specific method is as follows:

[0077] Huh-7 cells were seeded into 96-well plates at a cell density of 1.0 × 10 4 Each well was added with 100 μL of DMEM complete medium containing 10% FBS and 1% penicillin / streptomycin and cultured for 24 h. The supernatant was removed, the medium was replaced, 10 μL of polymer solution of different concentrations was added, and the cells were incubated for 48 h. The cells were washed with PBS, 100 μL of new medium was added, 10 μL of CCK-8 solution was added to each well, and the cells were incubated for 1 h. The absorbance at 450 nm was measured with a microplate reader.

[0078] Fig.10 It is the cytotoxicity of P2-5 and PEI 25kDa to huh-7 cells. As can be seen from the figure, when the carrier concentration reaches 6.25μg / ml, PEI 25kDa compound shows obvious cytotoxicity, while in contrast, when the carrier concentration of P2-5 compound is as high as 100μg / ml, the cell survival rate still reaches more than 80%, indicating that the cytotoxicity of P2-5 compound is significantly lower than that of PEI 25kDa compound.

[0079] In summary, the present invention provides a method for preparing functionalized polyethyleneimine, which is mild and efficient, does not require an external catalyst, is easy to purify, has an atomic utilization rate of 100%, has adjustable components, is convenient for combination screening, and is synthesized on a large scale; the prepared functionalized polyethyleneimine is stimuli-responsive, and its cytotoxicity is significantly lower than that of polyethyleneimine, and is expected to be used in gene transfection.

[0080] The above-described embodiments are only preferred embodiments for fully illustrating the present invention, and the protection scope of the present invention is not limited thereto. Equivalent substitutions or changes made by those skilled in the art based on the present invention are within the protection scope of the present invention. The protection scope of the present invention shall be subject to the claims.

Claims

1. A method for preparing a functionalized polyethyleneimine having stimulus responsiveness, characterized in that: The following steps are involved: S1. Under a protective atmosphere, polyethyleneimine, a monomer WF containing a functional group and an excess of a substituted or unsubstituted lactone compound are reacted in a solvent so that the functional group on the monomer is grafted onto the polyethyleneimine; S2. In an oxidizing atmosphere or an oxidizing agent, the grafted polyethyleneimine undergoes an oxidative coupling reaction to obtain the functionalized polyethyleneimine; Among them, the lactone compound is a thiolactone and / or a selenolactone; the structural formula of the lactone compound is , where X = S or Se, 0 < m < 8, and m is an integer; Y is selected from H, OH, NH2, substituted or unsubstituted alkyl, ether group, ester group, acid anhydride, amide, imine, oxime, hydrazine; The monomer containing a functional group is WF, wherein W is a halogenated hydrocarbon, an acyl halide or a conjugated compound containing a carbon-carbon double bond / triple bond, and F is a functional group; the functional group is a group with biocompatibility, a group with anti-protein / anti-serum function; or a tracing / detection group with ultraviolet absorption, fluorescence emission or radioactivity function.

2. The method for preparing a stimuli-responsive functionalized polyethyleneimine according to claim 1, characterized in that: In step S1, the functional groups include one or more of cholesterol groups, phosphorylcholine groups, polyethylene glycol groups, chitosan groups, cellulose groups, and fluoride groups.

3. The method for preparing a stimuli-responsive functionalized polyethyleneimine according to claim 1, characterized in that: In step S1, the thiolactone comprises , , One or more of; the selenolactone includes , , One or more of .

4. The method for preparing a stimuli-responsive functionalized polyethyleneimine according to claim 1, characterized in that: In step S1, the monomer containing a functional group includes , , , , , One or more of .

5. The method for preparing a stimuli-responsive functionalized polyethyleneimine according to claim 1, characterized in that: In step S1, the polyethyleneimine is linear polyethyleneimine or branched polyethyleneimine; And / or, the molecular weight of the polyethyleneimine is 500-25000.

6. The method for preparing a stimuli-responsive functionalized polyethyleneimine according to claim 1, characterized in that: In step S1, the protective atmosphere is a nitrogen atmosphere or an argon atmosphere; and / or, the solvent is water and / or an organic solvent; And / or, the reaction time is 5-500 min.

7. The method for preparing a stimuli-responsive functionalized polyethyleneimine according to claim 1, characterized in that: In step S1, the molar ratio of the amino group to the lactone compound in the polyethyleneimine is 100:1-100; And / or, the molar ratio of the lactone compound to the functional group in the monomer containing the functional group is 1:0.1-1.

8. The method for preparing a stimuli-responsive functionalized polyethyleneimine according to claim 1, characterized in that: In step S2, the oxidizing atmosphere is air, and the oxidation time is 1-24 h.

9. The functionalized polyethyleneimine having stimulus responsiveness prepared by the method according to any one of claims 1 to 8.

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