CN103601897A - Preparation method and application of multiple-response nanogel - Google Patents

Abstract

The invention relates to a preparation method and application of a multi-response nano gel, specifically: reacting 2-nitrobenzyl alcohol and methacryloyl chloride to obtain 2-nitrobenzyl methacrylate. Then monomers dimethylaminoethyl methacrylate and 2-nitrobenzyl methacrylate were polymerized into amphiphilic polymers by atom transfer radicals to prepare micelles. Then, 1,2-bis(2-iodoethoxy)ethane was added into the micellar solution as a cross-linking agent, and the shell of the micelles formed a cross-linked network, thereby preparing a shell-cross-linked nanogel. The nanogel has the following functions: (1) nanoscale carrier, which can stably load guest molecules, (2) controllable release of guest molecules by adjusting external fields such as ultraviolet light irradiation, pH and temperature, (3) various external fields can The kinetic release process of the guest molecule is regulated to produce a synergistic effect. The invention has wide application value in the fields of nanometer medicine, biosensor and nanoreactor.

Description

Preparation method and application of a kind of multiple response nanogel

the

technical field

The invention belongs to the technical field of polymer materials, and relates to the preparation and application of a multifunctional shell crosslinked nanogel.

Background technique

Nanogels are a class of nanoscale physically or chemically cross-linked polymer particles. Its unique nanoscale effect, good stability, and adjustable particle size have attracted a large number of researchers to apply it to different fields in the past decade, including sensing, medical diagnosis, and drug release. , and made great breakthroughs.

However, there is still room for improvement in at least two aspects of nanogels. The first one concerns the preparation method of nanogels. Most nanogels are prepared by emulsion polymerization or inverse emulsion polymerization, which requires a complicated post-purification process, which limits its industrial application. The second is that nanogels that respond to external stimuli, especially multi-responsive nanogels that combine light, temperature and pH, are still under development.

Prior to this, the applicant applied for a patent application with the publication number 103204971A, which was to copolymerize nitrobenzene derivative groups with photoresponsiveness and dimethylaminoethyl methacrylate with pH and temperature responsiveness to obtain multiple response Sexual amphiphilic polymers, self-assembled into micellar self-assembled bodies from this polymer in aqueous solution; but it only includes the materials and general process steps selected for preparation, and the present invention is further developed through previous inventions In-depth research and modification, material selection and proportioning, process correction, optimization and then applied to this patent application, combined with the method for preparing shell cross-linked nanogel of the present invention to obtain the shell cross-linked nanogel of the present invention. For example, the molar ratio of 2-nitrobenzyl alcohol and triethylamine, and the determination of the ratio of methacryloyl chloride and 2-nitrobenzyl alcohol are all different from before, and the selected ratio of the present invention can be more effective The use of 2-nitrobenzyl alcohol can reduce the reaction by-products; new research has also been carried out on the preparation of polymers, such as the selection of material ratios, process parameters, etc., so that the obtained polymers can form more excellent nano Structure; the nano gel further prepared by using the micelle-like self-assembled body obtained by the above preparation method enables the nano carrier to exist stably in a complex environment, further broadening its application range.

Contents of the invention

In order to solve the above problems, the present invention adopts a simple method to prepare a novel multi-functional shell cross-linked nanogel with light, acid and temperature.

The present invention copolymerizes nitrobenzene derivative groups with photoresponsiveness and dimethylaminoethyl methacrylate with pH and temperature responsiveness to obtain an amphiphilic polymer with multiple responsiveness, from which the polymer is Self-assemble into micellar self-assembly in aqueous solution, and then use cross-linking agent to specifically cross-link the specific part (shell layer) of polymer micelles, so as to obtain shell cross-linked nanogel with multiple responses.

Technical scheme of the present invention is: a kind of preparation method of the nano gel of shell crosslinking, its reaction mechanism is as follows:

The method specifically includes the following steps:

Step 1: Preparation of 2-nitrobenzyl methacrylate: Mix 2-nitrobenzyl alcohol and triethylamine in a molar ratio of 1:1-1:4 and dissolve in a round bottom filled with dichloromethane In the flask, put the round-bottomed flask in an ice-water mixing bath, and slowly add the dichloromethane solution dissolved in methacryloyl chloride into the round-bottomed flask drop by drop, in which, methacryloyl chloride and 2-nitrobenzyl The base alcohol ratio is 1:1~5:1; the whole reaction system is protected with nitrogen, and the reaction time is 6-12 hours; after the reaction is completed, pour the reaction mixture into a separatory funnel and wash it twice with alkaline aqueous solution; The organic layer was taken out from the separatory funnel, and dried with anhydrous sodium bisulfate for 12-24 hours to obtain the crude product; it was purified by silica gel column chromatography, and the chromatographic liquid was n-hexane and acetic acid with a volume ratio of 6:1 Ethyl ester mixed solution; The product obtained is light yellow liquid, standby;

Step 2: Preparation of polymer: the ampoule was vacuum-dried and filled with nitrogen, and the molar ratio of cuprous bromide, dimethylaminoethyl methacrylate and 2-nitrobenzyl methacrylate was 1:50:10 -Add the ratio of 1:10:10 to the ampoule, mix well, and use the sum of the mass of the above-mentioned cuprous bromide, dimethylaminoethyl methacrylate and 2-nitrobenzyl methacrylate for 2~10 times THF dissolved; 1,1,4,7,10,10-hexamethyltriethylenetetramine (0.1 to 1.0 mol) was added to the system with a syringe; Method After three times of treatment, react in an oil bath for 6-24 hours, the reaction temperature is 60°C to 80°C, after the reaction is completed, the product is passed through a chromatographic column equipped with alumina nanoparticles to remove excess catalyst, and the crude The product was rotary evaporated, precipitated in n-hexane, and dried in vacuum at 40°C to obtain an amphiphilic polymer;

Step 3: Self-assembly process: Mix the amphiphilic polymer and tetrahydrofuran obtained in step 2 at a mass ratio of 1:1; after the polymer is fully dissolved, mix 1 ml of deionized water at 1-3 microliters per second Slowly add it dropwise to the mixed solution at a speed of 10 to induce the formation of micelles, and continue to stir vigorously for 2-8 hours; add 8ml of deionized water to the mixed solution, and stop stirring; dialyze the solution in deionized water for at least After 24 hours, a micellar solution with triple responsiveness to light, temperature and pH was obtained;

Step 4: Gelation process: Take the polymer micelle solution obtained in step 3, and add 1,2-bis(2-iodoethoxy)ethane solution dropwise into the polymer micelle solution; the amount added is 5% ~ 20% of the polymer micelle solution; put the mixed solution at 60~80°C for 12-~24 hours; dialyze the gel solution obtained after the reaction with a dialysis membrane to obtain a pure nanogel solution .

Further, in the step 1, the charging amount of dichloromethane is 20%～80% of the flask.

Further, in the step 1, the alkaline aqueous solution is selected from sodium hydroxide aqueous solution or potassium hydroxide aqueous solution.

Further, in the "freezing-pumping-dissolving" method in step 2, the freezing temperature is -10°C~-20°C until freezing, and the pumping time is 10~30min; the dissolution can be It can be dissolved in the air or in a warm water bath, and it is the standard to achieve the purpose of dissolution.

Preferably, in the step 2, the molar ratio of cuprous bromide, dimethylaminoethyl methacrylate and 2-nitrobenzyl methacrylate is 1: 50: 10 ~ 1: 10: 10 Add to ampoule.

Further, the nanogel obtained in step 4 has a core-shell structure; its shell layer is a cross-linked layer with a three-dimensional network structure, and its composition is dimethyl methacrylate with hydrophilic partial quaternization Amino ethyl ester, the core layer is hydrophobic poly 2-nitrobenzyl methacrylate.

Further, the nanogel prepared by the method can be used as a nanoscale loader, which has good stability at room temperature and neutral conditions, but can release the loaded guest molecules under pH, temperature and ultraviolet light irradiation.

Further, the nanogel prepared by the method has a synergistic effect, and can regulate the kinetic release process of the guest molecule under different external stimulation conditions.

A nanogel prepared according to the method of the present invention. Applied to the field of controlled release of external stimuli, the details are as follows:

Dissolve 2 mg of the amphiphilic polymer based on nitrobenzene derivatives obtained in the above steps into 1 ml of tetrahydrofuran, add 0.3 mg of Nile red molecules at the same time, and fully stir for 30 molecules with a magnetic stirrer to make the polymer and Nile red Red was completely dissolved in tetrahydrofuran to form a homogeneous solution, and then 1 ml of deionized water was slowly dropped into the solution at a rate of 1 microliter per second, and vigorously stirred for 3 hours to induce the formation of micelles. Then 8 mL of deionized water was added to the solution to immobilize the formed micelles. Then 1 mL of the micellar solution 1,2-bis(2-iodoethoxy)ethane solution (12 mg/mL, dissolved in THF) was added dropwise to the polymer micellar solution. The mixed solution was reacted at 60° C. for 24 hours. The gel solution obtained after the reaction was dialyzed with a 10,000 g/mol dialysis membrane for at least 24 hours to remove tetrahydrofuran and small particles in the solution to obtain a nanogel solution loaded with guest molecules.

The polymer material used in this study is a cross-linked amphiphilic polymer. Amphiphilic polymer refers to a phase structure in which the same polymer has two phase structures with different properties (such as water phase and oil phase, two oil phases, and two incompatible solid phases) with affinity. Amphiphilic polymers can assemble to form micelles in selective solvents (a good solvent for one segment and a poor solvent for the other segment). Among them, the spherical polymer micellar self-assembly is the most common polymer system, in which the poorly soluble polymer forms the core of the micelles, while the more soluble chain segments form the micellar shell. Due to the existence of the solvation shell, the micelles formed by amphiphilic polymers can exist stably for a long time in a certain concentration range, but at lower concentrations such as below the critical micelle concentration, the self-assembled structure disintegrates and the micelles rupture . Therefore, cross-linking self-assembled micelles to form nanogels can greatly improve their stability.

Nanogels formed by self-assembled micelles of amphiphilic polymers can be used as drug carriers, and have many advantages, such as strong stability, good biocompatibility, and solubilization for drugs with little solubility. effect, and can be chemically modified on the surface of the gel to obtain a targeted drug delivery carrier. The hydrophobic core of the polymer nanogel can be loaded with hydrophobic drugs and serve as a drug storage pool, and the hydrophilic shell can reduce the interaction between micelles and phagocytes in vivo, which is conducive to the uniform dispersion of nanogels in water.

Stimuli-responsive polymer nanogels have great application prospects in the field of controlled release. Among them, temperature responsiveness and pH responsiveness have been studied the most, because the temperature of cells in many lesions is higher than that of normal cells, and the cell fluid is acidic. When the polymer nanogel runs to the lesion site in the human body, it will be stimulated by temperature or pH, and the shape of the polymer will change, thereby releasing the loaded drug. Moreover, there are few reports on photoresponsive polymer nanogels, which can achieve controlled release at any time and any place, so as to achieve more precise release of drugs.

The benefit of the present invention lies in that the polymer nanogel prepared in the present invention has light response, temperature response and pH response, and can be loaded with guest molecules through a series of processes, and the loaded guest molecules will be released in a controlled manner under the action of the above-mentioned external field come out. When the polymer nanogel is irradiated with ultraviolet light, the polymer molecules in the nanogel core undergo a photodegradation reaction, thereby releasing the loaded guest molecules. In the case of elevated temperature, the original hydrophilic polymer chain segment turns into hydrophobic, which makes the nanogel shrink and squeezes out a part of the guest molecules from the carrier. Under acidic conditions, due to the protonation of polymer molecules, the hydrophilicity of the hydrophilic segment is enhanced, which induces the nanogel to swell, allowing the loaded guest molecules to fall out. The response behavior of the above-mentioned polymer nanogels under the action of an external field was proved by transmission electron microscopy and fluorescence spectroscopy. The invention has broad application prospects in the fields of drug controlled release and the like.

the Description of drawings

Figure 1 is a transmission electron microscope schematic diagram of the prepared nanogel not loaded with guest molecules;

Figure 2 is a schematic diagram of the transmission electricity of the blank nanogel after being irradiated with ultraviolet light for 20 minutes;

Fig. 3 is the transmission electron microscope schematic diagram of blank nanogel in the environment of pH 3;

Figure 4 is a schematic diagram of the transmission electron microscope of a blank nanogel in an environment at a temperature of 60 °C;

Figure 5 is a schematic diagram of the change of the fluorescence absorption intensity of Nile Red with different irradiation times of ultraviolet light for the prepared nanogel loaded with Nile Red;

Figure 6 is a prepared nanogel loaded with Nile Red, a schematic diagram of the variation of the fluorescence absorption intensity of Nile Red with temperature;

Figure 7 is a prepared nanogel loaded with Nile Red, a schematic diagram of the variation of the fluorescence absorption intensity of Nile Red with pH;

Figure 8 is a schematic diagram of the change of the release amount of Nile Red under the co-stimulation of pH, light and temperature for the prepared nanogel loaded with Nile Red.

the

Detailed ways

The technical solution of the present invention will be further described according to the specific implementation below.

Example 1

Preparation of 2-nitrobenzyl methacrylate: Dissolve 4.21 g of 2-nitrobenzyl alcohol and 7.68 ml of triethylamine in a 100-ml round-bottomed flask filled with dichloromethane, and place the round-bottomed flask at 0 °C in an ice-water mixture bath. The dichloromethane solution dissolved in methacryloyl chloride was added dropwise into the round bottom flask. The whole reaction system was protected with nitrogen, and the reaction time was 12 hours. After the reaction, the reaction mixture was poured into a separatory funnel, and washed twice with aqueous sodium hydroxide solution. The organic layer was taken out from the separatory funnel and dried over anhydrous sodium bisulfate for 12 hours. The obtained crude product was purified by silica gel column chromatography (the chromatographic solution was a mixed solution of n-hexane and ethyl acetate with a volume ratio of 6:1). The product obtained was a pale yellow liquid.

Prepare the polymer. The 5 mL ampoules were vacuum dried and filled with nitrogen. Add 0.15 g of cuprous bromide, 4.71 g of dimethylaminoethyl methacrylate and 2.21 g of 2-nitrobenzyl methacrylate into the ampoule and dissolve with 3 ml of tetrahydrofuran. Add 35 mg of 1,1,4,7,10,10-hexamethyltriethylenetetramine into the system by syringe. After the reaction mixture was treated three times by the method of "freezing-pumping-dissolving", it was reacted in an oil bath for 18 hours at a reaction temperature of 68 °C. After the reaction, the product was passed through a chromatographic column filled with alumina nanoparticles to remove excess catalyst. The crude product was rotary evaporated, precipitated in n-hexane, and dried under vacuum at 40°C to obtain a solid amphiphilic polymer.

Self-assembly process: the prepared amphiphilic polymer and tetrahydrofuran are mixed at a mass ratio of 1:1. After the polymer was fully dissolved, 1 ml of deionized water was slowly dropped into the mixed solution at a rate of 1-3 microliters per second to induce the formation of micelles, and the vigorous stirring was continued for 4 hours. Add 8 mL of deionized water to the mixed solution, and stop stirring. The solution was dialyzed in deionized water for at least 24 hours to obtain a micellar solution with triple responsiveness to light, temperature and pH without loading guest molecules.

Gelation process: Take the prepared polymer micelle solution, add 1,2-bis(2-iodoethoxy)ethane solution dropwise to the polymer micelle solution; 5% (volume ratio) of the solution; place the mixed solution at 60°C for 12 hours; dialyze the gel solution obtained after the reaction with a dialysis membrane to obtain a pure nanogel solution. Figure 1 is the transmission electron microscope image of the nanogel, from which it can be seen that it has a perfect nanoscale spherical structure and is well distributed.

Characterization of multiple responsiveness: We use transmission electron microscopy to observe the shape changes of nanogels under light, pH and temperature. Figure 2 is the morphology of the nanogel after 20 minutes of light exposure. It can be seen that the nanogel has become slightly larger and has a small amount of hollow inside. Figure 3 shows the morphology of the nanogel at a pH of 3. It can be seen that the nanogel has become significantly larger, which is caused by the change of the hydrophilic-hydrophobic balance inside the gel. Figure 4 is a schematic diagram of the transmission electron microscope of the nanogel in an environment at a temperature of 60 °C. It can be seen that the size of the nanogel becomes significantly smaller, about 70 nanometers.

Example 2

Preparation of 2-nitrobenzyl methacrylate: Dissolve 8.42 g of 2-nitrobenzyl alcohol and 23.04 ml of triethylamine in a 100-ml round-bottomed flask filled with dichloromethane, and place the round-bottomed flask at 0 °C in an ice-water mixture bath. The dichloromethane solution dissolved in methacryloyl chloride was added dropwise into the round bottom flask. The whole reaction system was protected with nitrogen, and the reaction time was 12 hours. After the reaction, the reaction mixture was poured into a separatory funnel, and washed twice with aqueous sodium hydroxide solution. The organic layer was taken out from the separatory funnel and dried over anhydrous sodium bisulfate for 12 hours. The obtained crude product was purified by silica gel column chromatography (the chromatographic solution was a mixed solution of n-hexane and ethyl acetate with a volume ratio of 6:1). The product obtained was a pale yellow liquid.

Prepare the polymer. The 5 mL ampoules were vacuum dried and filled with nitrogen. Add 0.3 g of cuprous bromide, 9.42 g of dimethylaminoethyl methacrylate and 4.42 g of 2-nitrobenzyl methacrylate into the ampoule, and dissolve with 6 ml of tetrahydrofuran. Add 70 mg of 1, 1, 4, 7, 10, 10-hexamethyltriethylenetetramine into the system with a syringe. After the reaction mixture was treated three times by the method of "freezing-pumping-dissolving", it was reacted in an oil bath for 20 hours at a reaction temperature of 75 °C. After the reaction, the product was passed through a chromatographic column filled with alumina nanoparticles to remove excess catalyst. The crude product was rotary evaporated, precipitated in n-hexane, and dried under vacuum at 40°C to obtain a solid amphiphilic polymer.

self-assembly process. Dissolve 2 mg of the amphiphilic polymer based on nitrobenzene derivatives into 1 ml of THF, add 0.2 mg of Nile Red at the same time, and stir thoroughly with a magnetic stirrer for 3 minutes, so that the Nile Red and the polymer are completely dissolved in THF form a homogeneous solution. Then 1 ml of deionized water was added dropwise to the solution at a rate of 1 microliter per second. After the addition was complete, stirring was continued for 4 hours to induce the formation of micelles. Finally, 8 mL of deionized water was added to fix the formed micelles. The micellar solution is dialyzed in a dialysis bag for at least 24 hours to remove the Nile Red and THF in the solution to obtain the Nile Red-loaded micellar solution.

Gelation process: Take the prepared polymer micelle solution, add 1,2-bis(2-iodoethoxy)ethane solution dropwise to the polymer micelle solution; 10% (volume ratio) of the solution; the mixed solution was placed at 70°C for 36 hours; the gel solution obtained after the reaction was dialyzed with a dialysis membrane to obtain a pure nanogel solution.

Characterization of release performance: In order to show that the nanogel has the ability of responsive release, we chose Nile red as the guest molecule to observe its release. Fig. 5 is a schematic diagram showing the change of the fluorescence absorption intensity of Nile Red with different irradiation times of ultraviolet light for the nanogel loaded with Nile Red. It can be seen that with the increase of illumination time, the fluorescence intensity of Nile Red gradually decreases, showing its good release performance. Fig. 6 is a schematic diagram showing the variation of the fluorescence absorption intensity of Nile Red with temperature for the prepared nanogel loaded with Nile Red. It can be seen that the fluorescence intensity of Nile Red decreases with the increase of temperature. Figure 7 is a schematic diagram of the prepared nanogel loaded with Nile Red. The fluorescence absorption intensity of Nile Red varies with pH. As the pH drops, the nanogel expands, thereby releasing the Nile Red loaded therein. .

the

Example 3

Preparation of 2-nitrobenzyl methacrylate: Dissolve 6.315 g of 2-nitrobenzyl alcohol and 5.76 ml of triethylamine in a 100-ml round-bottomed flask filled with dichloromethane, and place the round-bottomed flask at 0 °C in an ice-water mixture bath. The dichloromethane solution dissolved in methacryloyl chloride was added dropwise into the round bottom flask. The whole reaction system was protected with nitrogen, and the reaction time was 12 hours. After the reaction, the reaction mixture was poured into a separatory funnel, and washed twice with aqueous sodium hydroxide solution. The organic layer was taken out from the separatory funnel and dried over anhydrous sodium bisulfate for 12 hours. The obtained crude product was purified by silica gel column chromatography (the chromatographic solution was a mixed solution of n-hexane and ethyl acetate with a volume ratio of 6:1). The product obtained was a pale yellow liquid.

Prepare the polymer. The 5 mL ampoules were vacuum dried and filled with nitrogen. Add 0.225 g of cuprous bromide, 7.065 g of dimethylaminoethyl methacrylate and 3.315 g of 2-nitrobenzyl methacrylate into the ampoule and dissolve with 4.5 ml of tetrahydrofuran. Add 52.5 mg of 1,1,4,7,10,10-hexamethyltriethylenetetramine into the system by syringe. After the reaction mixture was treated three times by the "freezing-pumping-dissolving" method, it was reacted in an oil bath for 24 hours at a reaction temperature of 80 °C. After the reaction, the product was passed through a chromatographic column filled with alumina nanoparticles to remove excess catalyst. The crude product was rotary evaporated, precipitated in n-hexane, and dried under vacuum at 40-80°C to obtain a solid amphiphilic polymer.

self-assembly process. Dissolve 2 mg of the amphiphilic polymer based on nitrobenzene derivatives into 1 ml of tetrahydrofuran, add 0.2 mg of Nile Red at the same time, and stir thoroughly with a magnetic stirrer for 5-30 minutes, so that the Nile Red and the polymer are completely dissolved. A homogeneous solution was formed in THF. Then 1 mL of deionized water was slowly added dropwise to the solution. After the dropwise addition was complete, stirring was continued for 4-8 hours to induce the formation of micelles. Finally, 8 mL of deionized water was added to fix the formed micelles. Dialyze the micellar solution in the dialysis bag for at least

After 12-24 hours, remove the Nile Red and THF in the solution to obtain a Nile Red-loaded micellar solution.

Gelation process: Take the prepared polymer micelle solution, add 1,2-bis(2-iodoethoxy)ethane solution dropwise to the polymer micelle solution; 20% (volume ratio) of the solution; place the mixed solution at 80°C for 48 hours; dialyze the gel solution obtained after the reaction with a dialysis membrane to obtain a pure nanogel solution.

Characterization of the synergistic release effect: In order to further verify the synergistic release effect of the nanogel system with various stimulation conditions, we used a combination of various stimulation conditions to illustrate its effect. Fig. 8 is a schematic diagram showing the change of the release amount of Nile Red under co-stimulation of pH, light and temperature for the prepared nanogel loaded with Nile Red. It can be clearly seen from the figure that under two or three stimuli, the release ability of the nanogel has been greatly improved, and the effect is more obvious than that of a single stimulus, which makes the nanogel have a wider field of controlled release. application value. the

Claims (8)

1. a preparation method for multiple response nanogel, is characterized in that: its step comprises:

Step 1: preparation 2-nitrobenzyl methacrylic ester: by 2-nitrobenzyl alcohol and the triethylamine ratio mixing of 1:1-1:4 in molar ratio, be dissolved in the round-bottomed flask that methylene dichloride is housed, round-bottomed flask is placed on to frozen water to be mixed in bath, the dichloromethane solution that is dissolved with methacrylic chloride is slowly dropwise added drop-wise in round-bottomed flask, wherein, methacrylic chloride and 2-nitrobenzyl alcohol ratio are 1:1 ~ 5:1; Whole reaction system nitrogen protection, the reaction times is 6-12 hour; After reaction finishes, reaction mixture is poured in separating funnel, used alkaline aqueous solution washed twice; Organic layer is taken out from separating funnel, with the dry 12-24 hour of anhydrous slufuric acid hydrogen sodium, the crude product obtaining; With silica gel column chromatography, purify, described chromatographic solution is that volume ratio is normal hexane and the ethyl acetate mixture of 6:1; The product obtaining is weak yellow liquid, standby;

Step 2: prepare polymkeric substance: by ampoule vacuum-drying and be full of nitrogen, by cuprous bromide, dimethylaminoethyl methacrylate and 2-nitrobenzyl methacrylic ester in molar ratio for the ratio of 1:50:10-1:10:10 joins ampoule, mix, use the tetrahydrofuran (THF) of 2 ~ 10 times of above-mentioned cuprous bromide, dimethylaminoethyl methacrylate and 2-nitrobenzyl methacrylic ester three quality sums to dissolve; With syringe by 1, Isosorbide-5-Nitrae, 7,10,10-hexamethyl triethylene tetramine (0.1 to 1.0 mole) joins in system; Reaction mixture is processed after three times by " freezing-to bleed-to dissolve " method, in oil bath, react 6-24 hour, temperature of reaction is 60 ℃ to 80 ℃, after reaction finishes, product, by being equipped with in the chromatography column of aluminium oxide nano particle to go out unnecessary catalyzer, is revolved to steaming by crude product, in normal hexane, precipitate, 40 ℃ of oven dry of vacuum, obtain amphipathic nature polyalcohol;

Step 3: self-assembly process: the amphipathic nature polyalcohol that step 2 is obtained and tetrahydrofuran (THF) be take mass ratio as 1 to 1 mixing; After polymkeric substance fully dissolves, the speed by 1 ml deionized water with 1-3 microlitre per second is slowly added drop-wise in mixing solutions, and to induce the formation of micella, vigorous stirring continues 2-8 hour; 8ml deionized water is joined in mixing solutions, and stop stirring; Solution is placed in deionized water to dialysis at least 24 hours, obtains thering is light, the micellar solution of temperature and the triple responsivenesss of pH;

Step 4: gelation process: get the polymer micelle solution that step 3 obtains, two (2-iodine oxyethyl group) the ethane solution of 1,2-is dropwise joined in polymer micelle solution; Add-on is 5 % ~ 20 % of polymer micelle solution; This mixing solutions is placed at 60 ℃ and reacts 12-~ 24 hour; The gelating soln obtaining after reaction is dialysed with dialysis membrane, obtain pure nanogel solution.

2. the preparation method of multi-functional shell crosslinking nano gel according to claim 1, is characterized in that: in described step 1, the amount of being filled with of methylene dichloride is flask 20% ~ 80%.

3. the preparation method of multiple response nanogel according to claim 1, is characterized in that: in described step 1, described alkaline aqueous solution is selected aqueous sodium hydroxide solution or potassium hydroxide aqueous solution.

4. the preparation method of multiple response nanogel according to claim 1, is characterized in that: in " freezing-to bleed-to dissolve " method in described step 2, freezing temp is-10 ℃ ~-20 ℃ and is refrigerated to and freezes to be as the criterion, described in the time of bleeding be 10 ~ 30min.

5. the preparation method of multiple response nanogel according to claim 1, is characterized in that: the nanogel that described step 4 obtains is for having nucleocapsid structure; Its shell is the cross-linked layer with three-dimensional net structure, and moiety is the dimethylaminoethyl methacrylate with the quaternary ammonium salinization of hydrophilic portion, and its stratum nucleare is for having hydrophobic poly-2-nitrobenzyl methacrylic ester.

6. the preparation method of multiple response nanogel according to claim 1, is characterized in that: the temperature of reaction in oil bath in described step 2 is 75 ℃ to 80 ℃, reaction 20-24 hour.

7. the preparation method of multiple response nanogel according to claim 1, it is characterized in that: the nanogel that described method prepares is as the loading bin of nanoscale, good at normal temperature, neutrallty condition stability inferior, and can under pH, temperature and UV-irradiation, the guest molecule of loading be discharged.

8. the application of multiple response nanogel according to claim 1, is characterized in that: the nanogel that described method prepares has synergistic effect, can under different outfield incentive condition combinations, regulate the kinetics dispose procedure of guest molecule.

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