A dual-responsive nano-delivery system and a preparation method and application thereof

Abstract

This invention discloses a dual-responsive nanodelivery system, its preparation method, and its applications, belonging to the field of drug sustained release. The core carrier of this nanodelivery system is a polymer with a specific structure, which can self-assemble to form drug-loaded nanomicelles. Through rational molecular design and synthesis of a series of polyamino acid polymers, and by optimizing the reaction route and controlling the reaction conditions, the molecular weight and distribution of the carrier materials can be controlled. Utilizing the biological properties of polyamino acid molecules, the drug carrier possesses good biocompatibility. The drug loading rate of the carrier is improved through a dual drug loading mechanism of chemical bonding and physical encapsulation. The self-assembly behavior of macromolecules is improved by relying on hydrophilic and hydrophobic structures, giving the nanomicelles good dimensional stability and dispersibility. The relationship between molecular structure and performance is explored.

Description

Technical Field

[0001] This invention belongs to the field of drug sustained release, specifically relating to a drug delivery system with sensitive pH / GSH dual-responsive controlled release, thereby reducing the toxic side effects of chemotherapy drugs and improving the anti-tumor efficacy of the drugs. Background Technology

[0002] As a class of biopolymers with multiple advantages, polyamino acid materials are renowned for their excellent biocompatibility, extremely low cytotoxicity, and high drug-loading capacity. Drug-loaded nanoparticles with different stimuli-responsive properties can be prepared by modifying or altering the side-chain functional groups. Chemotherapy is one of the important clinical treatments for malignant tumors, but the short blood circulation time, poor targeting, and toxic side effects of traditional chemotherapy drugs limit their large-scale application. Drug-loaded nanomicelles can control the drug release rate and reduce drug toxicity, but their wide particle size distribution and irregular morphology make them easily recognized and cleared by the endothelial reticulum system, hindering targeted drug release. Therefore, overcoming the ubiquitous biological barriers in vivo and enhancing the deep penetration of drug-loaded nanoparticles into tumor tissues and precise drug release within tumor cells remains a major challenge in the field of drug sustained release.

[0003] The concentration of glutathione (GSH) in tumor tissues is 4-5 times higher than that in normal tissues. The extracellular GSH concentration in normal cells is 2 μM-20 μM, while the concentration inside tumor cells is 2 mM-10 mM, approximately 500-1000 times higher than in normal cells. Disulfide bonds maintain good structural stability during systemic circulation. Upon entering cancer cells, they rapidly break down to generate thiol groups. This causes a phase transition from hydrophobic to hydrophilic in the polymeric drug carrier, effectively disrupting the material structure and enabling intelligent drug release. Therefore, the specific differences between the reduced microenvironment and normal tissues provide insights into the active targeting and controlled release of antitumor drugs. Cystamine (Cys) is a diamino molecule containing disulfide bonds. The amino group in its structure can combine with the carbonyl group in doxorubicin (DOX) to form a Schiff base structure. Simultaneously, the disulfide bond can respond stimuli to changes in GSH. This invention designs and synthesizes a type of polyamino acid triblock copolymer with cystamine molecules attached to its side chains. By chemically loading the drug, the polymer acquires larger hydrophobic segments, thereby achieving a self-assembly effect and completing physical encapsulation of the drug. The designed drug-loaded nanomicelles can circulate stably in the blood, will not be adsorbed by serum proteins and will not precipitate. The spherical morphology can be well captured and internalized by HeLa cells, and can achieve targeted drug release upon encountering responsive stimuli. Summary of the Invention

[0004] In view of the shortcomings or defects of the existing technology, the purpose of this invention is to provide a drug delivery system with pH / GSH dual responsiveness controlled release, as well as its preparation method and its application in the preparation of antitumor drugs, especially in drug sustained release.

[0005] A drug delivery system with pH / GSH dual-responsive controlled release, the core carrier of which is a polymer with a specific structure, as shown in structural formula (I), which can self-assemble into drug-loaded nanomicelles, the structure of which is as follows. Figure 1 As shown.

[0006]

[0007] Where n is an integer from 10 to 100, preferably an integer from 10 to 30.

[0008] A method for preparing a drug delivery system with pH / GSH dual-responsive controlled release includes the following steps:

[0009] Step 1: Synthesis and Characterization of Amphiphilic Polyamino Acids

[0010] Using polyethylene glycol as an initiator, a ring-opening polymerization reaction was initiated between an anhydride containing multiple carboxyl amino acids and phenylalanine anhydride. Subsequently, the protecting group was removed, and the product was grafted with cystamine to prepare a triblock polyamino acid polymer material with hydrophilic and hydrophobic segments grafted with cystamine. The structure of the prepared polymer was characterized, and the influence of the polymer structure on its physicochemical properties was investigated.

[0011] Step 2: Preparation of drug-loaded nanomicelles

[0012] The polyamino acid polymer material obtained in step 1 is mixed with the tumor drug in an organic solvent to obtain drug-loaded nanomicelles.

[0013] Preferably, the polycarboxylic acid ring anhydride mentioned in step 1 is aspartic acid ring anhydride.

[0014] The preferred tumor drug in step 2 is doxorubicin.

[0015] The drug loading method of the nanomicelles mentioned in step 2 is chemical bonding and physical coating.

[0016] This invention studies the self-assembly process and trends of polymers. The surface morphology, microstructure, and dispersion of nanomicelles are observed using laser particle size analyzer (DLS) and transmission electron microscopy (TEM). Using the antitumor drug doxorubicin (DOX) as a model drug, the drug loading and encapsulation efficiency of a series of prepared drug carriers are tested under different conditions, summarizing the relationship between drug loading effect and structure. The changes in the microstructure and surface potential of polyamino acid molecules before and after drug loading are examined. The drug release patterns of different carriers under different pH values ​​and GSH concentrations are investigated. Drug release data are analyzed, and relevant mathematical models are used to fit the drug release characteristics of nanomicelles, exploring the responsive controlled release mechanism of the drug.

[0017] The cytotoxicity of the synthesized polymeric materials (using L929 and HeLa cells as research subjects): The apoptosis of cells before and after drug loading was studied using laser confocal microscopy and flow cytometry. The cell uptake behavior of drug-loaded nanomicelles was analyzed, thereby completing the study on the cell selectivity and in vitro antitumor efficacy of the nano-drug delivery system and demonstrating the biosafety of the carrier material.

[0018] This invention also provides the application of the drug delivery system with pH / GSH dual responsive controlled release in the preparation of antitumor drugs. The tumor includes any malignant solid tumor among cervical cancer, breast cancer, liver cancer, and lung cancer.

[0019] The beneficial effects of this invention are:

[0020] 1. Through rational molecular design and synthesis of a series of polyamino acid polymer materials, by optimizing reaction routes and controlling reaction conditions, the molecular weight and distribution of the carrier materials can be controlled. By utilizing the biological characteristics of polyamino acid molecules, the drug carrier can be made to have good biological safety.

[0021] 2. By employing a dual drug delivery mechanism of chemical bonding and physical encapsulation, the drug loading rate of the carrier is improved; by relying on hydrophilic and hydrophobic structures to improve the self-assembly behavior of macromolecules, nanomicelles possess good dimensional stability and dispersibility, and the relationship between molecular structure and performance is explored.

[0022] 3. Research the drug release mechanism by utilizing the altered hydrophilicity and hydrophobicity of nanomicelles in the microacidic environment of tumors and the characteristics of disulfide bond breaking. The two responses work synergistically to improve the drug release rate and release speed, achieving targeted drug release at specific sites. Investigate the effects of the introduction of characteristic functional groups on cellular uptake and tissue compatibility, providing a scientific basis for optimizing molecular design. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of block polyamino acid polymer materials and drug-loaded nanomicelles.

[0024] Figure 2 This is a schematic diagram of the structure and preparation process of doxorubicin-loaded nanomicelles.

[0025] Figure 3 Before deprotection, the three samples 1 H NMR spectra and their assignments.

[0026] Figure 4 For the three samples before grafting, after hydrolysis protection. 1 H NMR spectra and their assignments.

[0027] Figure 5 After grafting cysteine, the three samples 1 H NMR spectra and their assignments.

[0028] Figure 6 The cell viability diagrams after co-culturing L929 cells with the three block copolymers are shown: (a) P1-Cys; (b) P2-Cys; (c) P3-Cys.

[0029] Figure 7 The particle size distribution diagrams are for three types of drug-loaded nanomicelles: (a) P1-DOX; (b) P2-DOX; (c) P3-DOX.

[0030] Figure 8 This is a graph showing the sustained release of P1-DOX under different pH values ​​and in different GSH environments.

[0031] Figure 9 This figure shows the sustained release of P2-DOX under different pH values ​​and in different GSH environments.

[0032] Figure 10 This figure shows the sustained release of P3-DOX under different pH values ​​and in different GSH environments.

[0033] Figure 11 This is a graph showing the relative toxicity analysis of free doxorubicin and three drug-loaded nanomicelles on HeLa cells.

[0034] Figure 12 Transmission electron microscopy (TEM) images of three types of drug-loaded nanomicelles: (a) P1-DOX; (b) P2-DOX; (c) P3-DOX.

[0035] Figure 13 This refers to the cellular uptake capacity of drug-loaded nanomicelles. Detailed Implementation

[0036] The solvent used in this invention is selected from Sinopharm Chemical Reagent Shenyang Co., Ltd., and other required raw materials are provided by the reagent library of Shenyang Pharmaceutical University.

[0037] Example 1

[0038] Research on the design and synthesis of polyamino acid polymers:

[0039] Using terminally aminated polyethylene glycol monomethyl ether (mPEG-NH2) as an initiator, hydrophilic segments were constructed by initiating the formation of anhydrides containing polycarboxylic acid rings. Hydrophobic segments were constructed by adding different proportions of phenylalanine anhydride (with repeating units n=10, 20, 30 in the structure). The product was then deprotected in a trifluoroacetic acid / hydrobromic acid (33%) co-solution. The molecular weight and distribution were controllable by controlling the amounts of initiator and monomer, and adjusting the proportions of repeating units in the polymer molecule.

[0040] The specific steps are as follows:

[0041] (I) Synthesis of triblock polymers

[0042] L-Aspartic acid-4-benzyl ester-N-carboxycyclic intracyclic anhydride (0.996 g) was dissolved in 5 mL of dry DMF and transferred to a round-bottom flask. The flask was then evacuated and purged three times with nitrogen to ensure a protective atmosphere. The initiator mPEG was then added. 113 -NH2 (2g) was dissolved in 7mL DMF and slowly injected into the reaction system. After reacting at 30℃ for 72h, L-phenylalanine-N-carboxylic acid anhydride (0.382g) was dissolved in 5mL DMF and slowly injected into the reaction system as the second stage of the reaction. After stirring for another 72h, the reaction was stopped. The solution was concentrated to a higher concentration by vacuum distillation. Using ice-cold ether as a poor solvent, a white powdery solid was obtained by precipitation and named P1-Cbz. Two other experiments were conducted with different feed ratios of L-phenylalanine-N-carboxylic acid anhydride. The other materials, operations and synthesis methods were the same as above.

[0043] The two products were consistently named P2-Cbz and P3-Cbz, respectively.

[0044] In the P1-Cbz structure, the phenylalanine repeating unit n=10; in the P2-Cbz structure, the phenylalanine repeating unit n=20; and in the P3-Cbz structure, the phenylalanine repeating unit n=30.

[0045] (ii) Removal of side chain protecting groups

[0046] Weigh 0.5 g of each of the three triblock polymers obtained in the previous step and dissolve them in 7 mL of TFA. Stir at room temperature for 50 min. Then, slowly add 5 mL of acetic acid solution (33%) containing HBr dropwise under an inert atmosphere. After the addition is complete, stir the system in an ice bath for 40 min, and continue stirring at room temperature for 20 min to stop the reaction. Subsequently, using ice-cold diethyl ether as a poor solvent, precipitate the polymers and filter them through a Buchner funnel at atmospheric pressure. Retain the filter cake to obtain the target products P1, P2, and P3, which are then dried in empty petri dishes for later use.

[0047] (III) Grafting of Cystamine Structure

[0048] Three portions of cystamine hydrochloride (7.16 g) were dissolved in 5 mL of DMF, and potassium carbonate (4.8 g) was slowly added to each solution. The mixture was stirred at room temperature in the dark for 12 h to remove hydrochloric acid. 0.0315 mol of the products obtained in the previous step (P1, P2, P3) were then weighed and dissolved in approximately 10 mL of DMF using sonication. Simultaneously, three portions of DCC (0.22 g) and three portions of NHS (0.12 g) were weighed and dissolved together in 10 mL of DMF. These solutions were then slowly added dropwise to the corresponding DMF solutions of the intermediates obtained in the previous step under ice bath conditions. After the addition was complete, the mixture was brought to room temperature and stirred for another 5 h. The corresponding cystamine solution was then slowly injected into the corresponding system, and the reaction was continued at 40°C for 48 hours. The byproduct N,N'-dicyclohexylurea (DCU) was removed by filtration. The solution was concentrated, and the polymer, a light yellow solid, was precipitated by ice-cold diethyl ether. It was washed three times with distilled water, then three times with methanol. The resulting solid was vacuum dried for 24 hours, stored in a low-temperature desiccator, and weighed. The yield was calculated to be 49.68%. These were designated as P1-Cys, P2-Cys, and P3-Cys for later use.

[0049] Example 2

[0050] Preparation and characterization of drug-loaded nanomicelles:

[0051] Drug-loaded nanomicelles were prepared using a nanoprecipitation method. For example... Figure 2As shown, 100 mg of doxorubicin hydrochloride (DOX·HCl) was dissolved in 50 mL of dimethyl sulfoxide (DMSO). 80 μL of triethylamine was added to the solution using a microsyringe. The mixture was stirred rapidly at room temperature in the dark for 4 h to activate the model drug. 100 mg of polymers P1-Cys, P2-Cys, and P3-Cys were weighed and dissolved in 20 mL of DMF in an Erlenmeyer flask (ultrasonic dissolution assisted). 5 mL of the activated doxorubicin solution was transferred to the system using a pipette. After stirring continuously in the dark for 24 h, deionized water was added dropwise to the system in small amounts to allow the polymer molecules to undergo sufficient self-assembly. After a total of 8 mL of water was added, the reaction system was transferred to a dialysis bag (molecular weight cutoff 3500 Da) and dialyzed in PBS solution at pH 7.4 for 24 h. The solution was changed every 6 h to remove solvent and excess small molecules of doxorubicin. The drug-loaded nanoparticles can be obtained as powdered solids by freeze-drying the dialysis solution. These powders are named P1-DOX, P2-DOX, and P3-DOX.

[0052] Example 3

[0053] Research on the responsive release mechanism of drug-loaded nanomicelles:

[0054] The drug release effect of nanomicelles was investigated by simulating the slightly acidic environment of tumor tissue. The UV-vis spectrophotometry of the sustained-release solution was measured within a predetermined time period to calculate the drug release amount. The drug release amount at different concentrations of GSH (0 mM, 10 mM) was tested to study its reduction sensitivity. A drug release model was established (spherical drug-loaded nanomicelles satisfying the Korsmeyer-Peppas model) to investigate the responsive release mechanism.

[0055] Example 4

[0056] Cellular evaluation of polymers and drug-loaded nanomicelles:

[0057] L929 cells and HeLa cells were cultured; the toxic effects of micelles and cell uptake behavior were observed using laser confocal microscopy (CLSM); cell apoptosis was examined by flow cytometry; the absorbance at 450 nm was measured using an enzyme-linked immunosorbent assay (ELISA) reader, and the relative cell viability was calculated.

[0058] Verification results:

[0059] Figure 3The figures show the 1H NMR spectra of P1-Cbz (n=10 phenylalanine repeating units), P2-Cbz (n=20 phenylalanine repeating units), and P3-Cbz (n=30 phenylalanine repeating units). The chemical shift a near 8.00 ppm is attributed to the NH group on the peptide bond in the main chain. Around 7.00 ppm, the chemical shift c of polyphenylalanine is at a higher field than the chemical shift b of the benzyl ester benzene ring. This is because, although the -CO-O- portion of the latter's ester group is indirectly connected to the benzene ring via -CH2-, the strong electron-withdrawing effect of the carbonyl group (C=O) is transferred to its benzene ring through the σ bond, reducing the electron cloud density of the benzene ring. Chemical shift d represents the methylene group of the benzyl ester. Due to the electron-withdrawing effect of the ester group, it shifts to a lower field. Its intensity, along with that of chemical shift e, can reflect the differences in the amino acid ratios in the three groups of drug-loaded micelles to some extent. In the initiator, the methylene signal intensity of the ether structure is also very high, with a characteristic peak f around the chemical shift of 3.50 ppm. Except for the water peak at chemical shift of 3.30 ppm and the solvent DMSO at 2.50 ppm, the positions of the other major peaks correspond to the proton hydrogen in the structure.

[0060] Figure 4 The images show the 1H NMR spectra of polymers P1, P2, and P3. Due to the removal of benzyl alcohol, a large number of carboxyl groups are exposed in the structures of all three polymers. The previously almost invisible α-H carboxyl / ester group appears as a chemical shift signal h (δ=1.80ppm). Simultaneously, the chemical shift of the benzene ring structure, which was originally a protecting group, disappears significantly. Notably, as the n value increases, the peak shape becomes relatively more pronounced. The signals b and c (δ=7.20ppm) of the benzene ring in the side chain of polymerized phenylalanine are significantly enhanced and clearer. The benzyl hydrogen of phenylalanine (chemical shift g, δ=2.90ppm), which was not obvious or clear in the previous image, is also present. Other chemical shifts belonging to different protons are all reflected at their corresponding positions. This all demonstrates the successful progress of the deprotection reaction.

[0061] Figure 5The images show the 1H NMR spectra of polymers P1-Cys, P2-Cys, and P3-Cys. The carboxyl α-H group, previously at a chemical shift of approximately δ=1.80 ppm, now shifts to a lower field, manifested as chemical shift signal i (δ=2.10 ppm). This is because the dissociation compensation effect of the carboxylic acid disappears after grafting, and the N lone pair electrons conjugate with the carbonyl group, increasing the deshielding intensity, which confirms the presence of cystamine. This suggests that the grafting of cystamine to the polymer was successful. Other cystamine-related chemical shifts, such as f (δ=3.50 ppm), overlap with the polyethylene glycol monomethyl ether moiety due to similar environmental conditions, making independent differentiation impossible. However, the increased peak area suggests the possibility of successful grafting. Interestingly, after the addition of cystamine, the chemical shifts of the benzene ring hydrogens belonging to phenylalanine were separated again, showing characteristic doublets b and c at around δ=7.00ppm and δ=6.50ppm. The chemical shifts of other characteristic groups, the chemical shifts a corresponding to multiple secondary amine hydrogens, and the chemical shift d corresponding to the tertiary carbon hydrogens of aspartic acid were also confirmed in the spectrum, further proving that the synthesized compound conforms to the molecular design.

[0062] Figure 6 The graph shows the cell viability after co-culturing the three block copolymers with L929 cells. After co-culturing the three block copolymers with L929 cells for 24 hours, each polyamino acid material was non-toxic to the cells. Even at a co-culture concentration of 500 μg / mL, the relative cell viability remained above 95%. All segments constituting the polymer materials are cell-compatible. mPEG exhibits strong hydrophilicity and can promote normal transport in systemic circulation. Aspartic acid and phenylalanine are essential components of human tissues, thus demonstrating good cell compatibility.

[0063] The average particle sizes of the three drug-loaded nanomicelles at pH 7.4 were 21.75 nm, 30.13 nm, and 85.66 nm, respectively. Under neutral conditions, the electrostatic interactions between groups weaken, which is beneficial for the hydrophobic groups of cystamine to promote the self-assembly of the macromolecular chains, resulting in a more uniform molecular arrangement. Phenylalanine itself has significant steric hindrance and strong hydrophobicity, leading to a larger particle size in the nanoparticles. The size of the nanomicelles tends to increase with increasing molecular weight and phenylalanine content. In all conditions, the particle size was less than 100 nm, which meets the particle size requirements for nanomicelles in the field of drug sustained release. (Particle size is as follows...) Figure 7 As shown. Under pH=7.4 environmental conditions, the molecular side chains did not exhibit protonation or deprotonation effects, and the nanomicelles showed more uniform behavior. After phosphotungstic acid staining, all drug-loaded nanomicelles exhibited a spherical morphology with smooth surfaces and uniform shape, consistent with the DLS trend. Transmission electron microscopy is shown below. Figure 12 As shown.

[0064] In vitro drug release experiments were conducted at 37°C in phosphate buffer (pH=5.4, 7.4) and glutathione environments (GSH=0mM, 10mM). The drug release of P1-DOX was as follows: Figure 8 As shown, the drug-loaded nanoparticles released 91.2%, 86.4%, and 45.7% of DOX in the three environments after 70 hours, respectively. The first two environments, both with glutathione, showed higher total release rates; however, the release rate was significantly lower in the glutathione-free environment, indicating that the drug-loaded micelles exhibit a relatively significant redox-responsive drug release behavior.

[0065] The drug release patterns of P2-DOX and P3-DOX show the same trend, such as Figure 9 , Figure 10 As shown, on the one hand, due to different environments, the morphology and distribution of particles vary, which can lead to changes in the release characteristics of model drugs. Under acidic conditions, the imine bonds formed between the polymer and the model drug DOX are easily broken, and de-self-assembly occurs. This allows a large amount of chemically bonded DOX to be released, disrupting the morphology of the nanoparticles and thus improving the release effect of the model drug. On the other hand, in the GSH environment, the disulfide bonds in the polymer side chains break rapidly, causing de-self-assembly and the disintegration of the nanomicelle structure, thereby achieving rapid drug release. Overall, this indicates that in normal physiological environments, slow drug release is beneficial for reducing toxic side effects; in the tumor microenvironment, the drug release rate and release rate are significantly increased, which is beneficial for improving therapeutic effects.

[0066] Figure 11 The relative cell viability of drug-loaded nanomicelles co-cultured with HeLa cells for 24 h is shown. Free DOX and Pn-DOX (P1-DOX, P2-DOX, and P3-DOX) all exhibited significant HeLa cytotoxicity, and cell viability decreased rapidly with increasing DOX concentration. Based on the previous good cytocompatibility of polymers with normal cells, it can be inferred that the toxicity of nanoparticles mainly originates from the loaded model drug. Free DOX diffuses automatically into cells via systemic circulation and is immediately captured by the cell nucleus; this process is rapid and uncontrollable, hence the relatively high cytotoxicity. Drug-loaded nanoparticles are targeted, releasing the drug only upon stimulation; the process is slow and easily controlled. The drug release process corresponds to the cellular uptake, further demonstrating that nanoparticles can achieve sustained drug release. Based on the study of self-assembly, it can be inferred that P2-DOX and P3-DOX contain more hydrophilic phenylalanine groups. The self-assembly effect of nanomicelles and the disassembly phenomenon of nanomicelles under stimulation are not simple reversible reactions and are quite different. Therefore, the drug release effect is stronger and the cell proliferation inhibition rate is more obvious.

[0067] Taking P2-DOX as an example, this study investigated the cellular uptake capacity of drug-loaded nanomicelles. Free DOX enters cancer cells primarily through passive diffusion in systemic circulation, mainly concentrating in the cell nucleus. Figure 13 The nanoparticles exhibited strong fluorescence, and the image shown is a CLSM photograph after 24 hours of co-culture. After bonding and encapsulating doxorubicin, the nanoparticles demonstrated excellent targeting. Within cancer cells, the chemical bonds broke in response to pH, and the drug was released through physical encapsulation via changes in microsphere morphology. Cell entry was achieved through endocytosis within the cell membrane, a relatively slow process. Red DOX signals were observed in both the nucleus and cytoplasm, and the fluorescence intensity increased with time (6 hours and 24 hours of co-culture). Under the influence of lysosomes and endosomes within the cell, the polymer nanomicelles underwent a pH response. A high GSH environment caused the core-shell structure to disintegrate. As can be seen from the image, the drug release process can achieve the goal of "slow release," demonstrating the feasibility of this study.

[0068] The above experiments demonstrate that the responsive drug delivery system of the present invention has a pH / GSH dual responsive controlled release function, and therefore can be used in the field of sustained release of antitumor drugs.

Claims

1. A dual-responsive based nanodelivery system, characterized in that, Its core carrier is a polymer with a specific structure, as shown in Formula (I), which can self-assemble to form drug-loaded nanomicelles. Where n is an integer between 10 and 100.

2. A method for preparing the dual-responsive nanodelivery system according to claim 1, characterized in that, Includes the following steps: Step 1: Using polyethylene glycol as an initiator, a ring-opening polymerization reaction was initiated between an anhydride containing polycarboxylic acid rings and phenylalanine anhydride. Subsequently, the protecting group was removed, and the product was grafted with cystamine to obtain a triblock polyamino acid polymer material with hydrophilic and hydrophobic segments and grafted with cystamine. Step 2: The prepared polyamino acid polymer material is mixed with the tumor drug in an organic solvent to obtain drug-loaded nanomicelles.

3. The preparation method of the dual-responsive nanodelivery system according to claim 2, characterized in that, The polycarboxylic acid ring anhydride mentioned above is aspartic acid ring anhydride.

4. The preparation method of the dual-responsive nanodelivery system according to claim 2, characterized in that, The tumor drug mentioned is doxorubicin.

5. The preparation method of the dual-responsive nanodelivery system according to claim 2, characterized in that, The drug delivery mechanism of the nanomicelles is chemical bonding and physical encapsulation.

6. The application of the dual-responsive nanodelivery system of claim 1 in the preparation of antitumor drugs.

7. The application according to claim 6, characterized in that, The tumor includes any of the following malignant solid tumors: cervical cancer, breast cancer, liver cancer, and lung cancer.

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