A dual stimuli-responsive polyphospholipid polymer, nano-delivery system, and preparation method and application thereof

Abstract

The application provides a kind of double stimulus responsive polythioic acid polymer, nano delivery system and its preparation method and application.The double stimulus responsive polythioic acid polymer described in the application includes glutathione responsive polythioic acid, and the carboxyl position of the glutathione responsive polythioic acid is grafted with polyethylene glycol group and tissue protease B responsive peptide chain covalent connection TLR7 / 8 agonist imidazoquinoline.The application takes PTA with good biocompatibility and glutathione degradability as skeleton, side chain is covalently connected with TLR7 / 8 agonist IMDQ through tissue protease B responsive peptide chain, self-assembled to form nanoparticle, can be accumulated in injection site and effectively drained to lymph node, responds to release IMDQ in antigen presenting cell (APC), realizes the accurate delivery and efficient release of IMDQ.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of biomedical materials, and particularly relates to a dual-stimulus-responsive polysulfoxy acid polymer, a nano-delivery system, and a preparation method and application thereof. BACKGROUND

[0002] The application of immune checkpoint inhibitors, chimeric antigen receptor (CAR) T cells, and cancer vaccines and other immunotherapeutic approaches has completely changed the status quo of cancer treatment. Among these treatment methods, cancer vaccines are considered a promising approach that can induce tumor regression and elicit a long-lasting, metastasis-preventing protective immune response. However, antigen-presenting cells have deficiencies in stimulating the innate immune system, which largely restricts the antigen cross-presentation and subsequent T cell immune activation elicited by cancer vaccines. Currently, innate immune signal agonists, including toll-like receptors (TLRs), retinoic acid-inducible gene 1-like receptors (RIG-1), and stimulator of interferon genes (STING), are being used as immune adjuvants to improve cancer vaccine efficiency.

[0003] TLR7 / 8 small molecule agonists are effective activators of antigen-presenting cells and have great potential as adjuvants in tumor vaccines. However, small molecule agonists like imidazoquinoline (IMDQ) often induce dose-dependent immune-related adverse events (irAEs), including potentially fatal cytokine storms, when administered systemically due to their rapid and uncontrollable systemic distribution, thus limiting their clinical application. Nanocarriers can increase the accumulation of TLR7 / 8 agonists in lymph nodes and reduce their distribution in non-target tissues, thereby reducing systemic inflammatory side effects. In addition, nanoparticles can effectively deliver TLR7 / 8 agonists to receptors on intracellular membranes, ultimately activating TLR7 / 8 signals and producing a strong innate immune response. Although various attempts, such as physical encapsulation and covalent attachment, have been reported to reduce the side effects of TLR7 / 8 agonists, how to precisely deliver TLR7 / 8 agonists in a free form to receptors on intracellular membranes and achieve stable encapsulation in a physiological environment remains a challenge.

[0004] Stimuli-responsive nanoparticles have incomparable advantages over traditional nanoparticles in tumor-selective drug delivery. Based on the unique characteristics of the intracellular and extracellular microenvironment, such as the difference in pH and enzyme expression, as well as the difference in the content of glutathione (GSH) and reactive oxygen species (ROS), many different stimulus-responsive agonist delivery systems have been designed, among which enzyme response has been widely concerned due to its specificity. In recent years, researchers have covalently combined enzyme-responsive bonds with agonists into nano-delivery carriers to enhance anti-tumor immunity and improve therapeutic effect. However, the non-degradable carrier skeleton will hinder the release of the agonist, thereby affecting the immune efficiency of the agonist. Therefore, it is still a challenge to achieve agonist-responsive release without affecting its immune efficiency.

[0005] In view of this, the present application is proposed. SUMMARY

[0006] The present application aims to provide a dual-stimuli-responsive polytaurine polymer, a nano-delivery system, and a preparation method and application thereof. The nano-delivery system provided in the present application can effectively enrich in lymph nodes after intramuscular injection and activate the body's immune system.

[0007] In order to achieve the above-mentioned purpose of the present application, the following technical solutions are adopted:

[0008] In a first aspect, the present application provides a dual-stimuli-responsive polytaurine polymer, which has the following structure shown in Formula I:

[0009]

[0010] Formula I

[0011] wherein x≥1, y≥1, z≥1, and n is 20-120.

[0012] Preferably, the x:y:z is (30-140):(1-10):(5-50).

[0013] Preferably, the molecular weight of the dual-stimuli-responsive polytaurine polymer is 20,000-200,000 Da.

[0014] Preferably, the dual-stimuli-responsive polytaurine polymer comprises glutathione-responsive polytaurine, and the glutathione-responsive polytaurine has a polyethylene glycol group grafted at the carboxyl position and a TLR7 / 8 agonist imidazoquinoline covalently connected through a cathepsin B-responsive peptide chain.

[0015] Preferably, the molecular weight of the polyethylene glycol is 1,000-5,000 Da.

[0016] Preferably, the molecular weight of the lipoic acid is 10000-50000 Da.

[0017] In a second aspect, the present application provides a preparation method of the double-stimulus-responsive lipoic acid polymer according to the first aspect, the preparation method comprising the following steps:

[0018] Fmoc-GFLG and IMDQ are subjected to a condensation reaction to obtain Fmoc-GFLG-IMDQ; the Fmoc-GFLG-IMDQ is subjected to a deprotection reaction to obtain GFLG-IMDQ;

[0019] The reaction route for preparing GFLG-IMDQ is shown as follows:

[0020] ;

[0021] Lipoic acid is subjected to a ring-opening polymerization reaction to obtain poly-lipoic acid;

[0022] The reaction route for preparing poly-lipoic acid is shown as follows:

[0023]

[0024] wherein m is 40-200;

[0025] Poly-lipoic acid, PEG-NH2 and GFLG-IMDQ are subjected to a condensation reaction to obtain the double-stimulus-responsive lipoic acid polymer shown in Formula I; the reaction formula is shown as follows:

[0026] .

[0027] wherein x≥1, y≥1, z≥1, and n is 20-120, preferably 44.

[0028] Preferably, the molar ratio of Fmoc-GFLG to IMDQ is 1:(1-1.2).

[0029] Preferably, in the process of preparing Fmoc-GFLG-IMDQ, the condensation reaction is carried out at a temperature of 0-30℃ for 4-8 h.

[0030] Preferably, in the process of preparing Fmoc-GFLG-IMDQ, the condensation reaction is carried out in the presence of a condensing agent, and the molar ratio of Fmoc-GFLG to condensing agent is 1:(1-2).

[0031] Preferably, in the process of preparing Fmoc-GFLG-IMDQ, the condensation reaction is carried out in the presence of a base, and the molar ratio of Fmoc-GFLG to base is 1:(1-3).

[0032] Preferably, the reagent used in the deprotection reaction is piperidine.

[0033] Preferably, the temperature of the deprotection reaction is 10-30℃, and the time of the deprotection reaction is 0.5-2 h.

[0034] Preferably, the temperature of the ring-opening polymerization reaction is 60-80℃, and the time of the ring-opening polymerization reaction is 1-2 h.

[0035] Preferably, the molar ratio of the lipoic acid, PEG-NH2 and GFLG-IMDQ is 1:(5-50):(1-10).

[0036] Preferably, in the process of condensation of the lipoic acid, PEG-NH2 and GFLG-IMDQ, the temperature of the condensation reaction is 0-30℃, and the time of the condensation reaction is 4-8 h.

[0037] Preferably, in the process of condensation of the lipoic acid, PEG-NH2 and GFLG-IMDQ, the condensation reaction is carried out in the presence of a condensing agent, and the molar ratio of the lipoic acid and the condensing agent is 1:(1-3).

[0038] Preferably, in the process of condensation of the lipoic acid, PEG-NH2 and GFLG-IMDQ, the condensation reaction is carried out in the presence of a base, and the molar ratio of the lipoic acid and the base is 1:(1-5).

[0039] In a third aspect, the present application provides a dual-stimulus-responsive nano-delivery system, which comprises the dual-stimulus-responsive lipoic acid-based polymer as described in the first aspect.

[0040] Preferably, the particle size of the dual-stimulus-responsive nano-delivery system is 50-500 nm.

[0041] Preferably, the dual-stimulus-responsive nano-delivery system further comprises dimethyl sulfoxide and water.

[0042] Preferably, in the dual-stimulus-responsive nano-delivery system, the concentration of the dual-stimulus-responsive lipoic acid-based polymer represented by Formula I is 5-10 mg / mL.

[0043] Preferably, the volume ratio of the dimethyl sulfoxide and water is 1:(10-500).

[0044] In a fourth aspect, the present application provides a preparation method of the dual-stimulus-responsive nano-delivery system as described in the third aspect, which comprises:

[0045] The double-stimulus-responsive polythioic acid polymer shown in I is dissolved in dimethyl sulfoxide to obtain a dimethyl sulfoxide solution of the polymer;

[0046] The dimethyl sulfoxide solution of the polymer is added dropwise to water, and stirring is performed to obtain the double-stimulus-responsive nano delivery system.

[0047] Preferably, the temperature is controlled to be 4-25°C during the dropwise addition.

[0048] Preferably, the stirring speed is controlled to be 100-3000 rpm during the dropwise addition.

[0049] Preferably, after the dropwise addition is completed, the stirring temperature is 4-25°C, the stirring speed is 100-3000 rpm, and the stirring time is 10-60 min.

[0050] In a fifth aspect, the present application provides a use of the double-stimulus-responsive polythioic acid polymer according to the first aspect or the double-stimulus-responsive nano delivery system according to the third aspect in the preparation of a tumor nano drug therapeutic agent.

[0051] Compared with the prior art, the present application has the following beneficial effects:

[0052] (1) The present application provides a highly efficient and precise double-stimulus-responsive nano delivery system. PTA with GSH responsiveness is used as a skeleton, and a TLR7 / 8 agonist IMDQ is covalently connected to the side chain through a cathepsin B-responsive peptide chain (GFLG) to form a double-stimulus-responsive nano delivery system.

[0053] (2) The double-stimulus-responsive nano delivery system of the present application can accumulate at the injection site and effectively drain to the lymph nodes, thereby reducing the clearance of the circulatory system and prolonging the aggregation time of IMDQ in the lymphatic tissue. After the nano particles are phagocytosed by antigen-presenting cells (APCs), the PTA backbone containing disulfide bonds is degraded by intracellular reducing GSH. Subsequently, the GFLG peptide chain is degraded by cathepsin B, releasing free IMDQ and stimulating TLR7 / 8 receptors located on the intracellular membrane to activate the body's own immune system. BRIEF DESCRIPTION OF DRAWINGS

[0054] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed in the specific embodiments or prior art description will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0055] Figure 1 NMR spectrum of the double stimuli-responsive polytaurine polymer provided for Preparation Example 1.

[0056] Figure 2 Particle size chart of the double stimuli-responsive nanodelivery system provided for Example 1.

[0057] Figure 3 Enzyme-responsive characterization chart of the double stimuli-responsive nanodelivery system provided for Example 1.

[0058] Figure 4 Flow cytometry characterization chart after treating BMDCs with the double-responsive nanoparticles.

[0059] Figure 5 Cytotoxicity characterization chart of the double-responsive nanoparticles.

[0060] Figure 6 Enrichment chart of the double-responsive nanoparticles in the inguinal lymph nodes. DETAILED DESCRIPTION

[0061] Unless otherwise defined, scientific and technical terms used in connection with the present application shall have the meanings that are commonly understood by those of ordinary skill in the art. The meaning and scope of the terms should be clear; however, in the event of any latent ambiguity, definitions provided herein take precedent over any dictionary or extrinsic definition. In this application, the use of "or" means "and / or" unless specifically stated otherwise, for example, a condition is A or B means A or B or A and B. Also, the use of "comprise", "comprises", "comprising", "containing", "includes", "including" and other variations thereof are to be construed as open ended, i.e., meaning "including, but not limited to".

[0062] It should be noted that specific details are set forth in the following description in order to provide a thorough understanding of the application. However, the application can be practiced without many of the details set forth, or with equivalents thereof, without departing from the scope of the application. Therefore, the application is not limited to the details below, but can be practiced with the scope of the application.

[0063] The technical solutions of the present application will be described clearly and completely in combination with the examples below. Obviously, the described examples are part of the examples of the present application, rather than all the examples. Based on the examples in the present application, all other examples obtained by those of ordinary skill in the art without making creative efforts fall within the scope of the present application.

[0064] In a first aspect, the present application provides a double stimuli-responsive polytaurine polymer, which has the following formula I structure:

[0065]

[0066] Formula I.

[0067] In the present application, an amphiphilic copolymer, i.e. polyethylene glycol (mPEG) modified polythioctic acid (PTA), is provided, and a TLR7 / 8 agonist imidazoquinoline (GFLG-IMDQ) is further modified with a cathepsin B responsive peptide chain connected to the side chain, finally obtaining a double-stimulus-responsive polythioctic acid polymer as shown in the above formula I.

[0068] Firstly, PTA is a GSH-responsive polymer polymerized from a-lipoic acid (a-LA), which is a natural antioxidant synthesized in the human body, has the advantages of regulating blood sugar, inhibiting appetite, resisting obesity, etc., and is often used for the treatment of diseases such as diabetes and Alzheimer's disease. Therefore, PTA has good biocompatibility and biodegradability, and its degradation products also have good biocompatibility and safety. Secondly, the present application selects the TLR7 / 8 agonist IMDQ, which is covalently combined with the hydrophobic block of the GSH-responsive block copolymer through the cathepsin B responsive bond gly-ph-leu-gly (GFLG) to self-assemble into core-shell nanoparticles. These nanoparticles can accumulate at the injection site and effectively drain to the lymph nodes, thereby reducing the clearance of the circulatory system and prolonging the aggregation time of IMDQ in the lymphatic tissue. After the nanoparticles are phagocytosed by APCs, the PTA main chain containing disulfide bonds is degraded by intracellular reducing GSH. Subsequently, the linker GFLG is exposed to cathepsin B and degraded, releasing free IMDQ and stimulating TLR7 / 8 receptors located on the intracellular membrane, thereby achieving efficient release and precise delivery of IMDQ, achieving higher immunotherapy efficiency and reducing the level of systemic toxicity.

[0069] As an optional embodiment, in the double-stimulus-responsive polythioctic acid polymer shown in the above formula I, x≥1, which can be 1, 2, 4, 5, 6, 8, 10, 15, 20, 30, 40, 50, 60, 80, 100, etc.

[0070] As an optional embodiment, in the double-stimulus-responsive polythioctic acid polymer shown in the above formula I, y≥1, which can be 1, 2, 4, 5, 6, 8, 10, 15, 20, 30, 40, 50, 60, 80, 100, etc.

[0071] As an optional embodiment, in the double-stimulus-responsive polythioctic acid polymer shown in the above formula I, z≥1, which can be 1, 2, 4, 5, 6, 8, 10, 15, 20, 30, 40, 50, 60, 80, 100, etc.

[0072] As an optional embodiment, in the dual-stimulus-responsive polythioctic acid polymer shown in the above formula I, n is 20-120, for example, can be 20, 22, 24, 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, 48, 50, 52, 54, 56, 58, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, etc.

[0073] As an optional embodiment, in the dual-stimulus-responsive polythioctic acid polymer shown in the above formula I, the x:y:z is (30-140):(1-10):(5-50).

[0074] Among them, "30-140" can be 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, etc.

[0075] Among them, "1-10" can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, etc.

[0076] Among them, "5-50" can be 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, etc.

[0077] As an optional embodiment, the molecular weight of the dual-stimulus-responsive polythioctic acid polymer shown in the above formula I is 20000-200000 Da, for example, can be 20000 Da, 30000 Da, 40000 Da, 50000 Da, 60000 Da, 70000 Da, 80000 Da, 90000 Da, 100000 Da, 120000 Da, 140000 Da, 160000 Da, 180000 Da, 200000 Da, etc.

[0078] As an optional embodiment, the dual-stimulus-responsive polythioctic acid polymer includes glutathione-responsive polythioctic acid, and the glutathione-responsive polythioctic acid is grafted with a polyethylene glycol group and a TLR7 / 8 agonist imidazoquinoline covalently connected with a cathepsin B-responsive peptide chain.

[0079] It should be noted that the present application provides a dual-stimulus-responsive nano-delivery system, which is self-assembled from glutathione-responsive polythioctic acid grafted with polyethylene glycol of TLR7 / 8 agonist imidazoquinoline (GFLG-IMDQ) connected with a cathepsin B-responsive peptide chain in the side chain ((PTA-g-mPEG)-GFLG-IMDQ).

[0080] As an optional embodiment, the molecular weight of the polyethylene glycol is 1000-5000 Da, for example, it can be 1000 Da, 1500 Da, 2000 Da, 2500 Da, 3000 Da, 3500 Da, 4000 Da, 4500 Da, 5000 Da, etc., preferably 3500-5000 Da.

[0081] As an optional embodiment, the molecular weight of the lipoic acid is 10000-50000 Da, for example, it can be 10000 Da, 15000 Da, 20000 Da, 25000 Da, 30000 Da, 35000 Da, 40000 Da, 45000 Da, 50000 Da, etc., preferably 25000-30000 Da.

[0082] In a second aspect, the present application provides a preparation method of the dual-stimulus-responsive lipoic acid-based polymer according to the first aspect, and the preparation method comprises the following steps:

[0083] Fmoc-GFLG and IMDQ are subjected to a condensation reaction to obtain Fmoc-GFLG-IMDQ; the Fmoc-GFLG-IMDQ is subjected to a deprotection reaction to obtain GFLG-IMDQ;

[0084] The reaction route for preparing GFLG-IMDQ is as shown below:

[0085] ;

[0086] The lipoic acid is subjected to a ring-opening polymerization reaction to obtain poly-lipoic acid;

[0087] The reaction route for preparing poly-lipoic acid is as shown below:

[0088] ;

[0089] wherein m is 40-200, for example, it can be 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, etc.

[0090] The poly-lipoic acid, PEG-NH2 and GFLG-IMDQ are subjected to a condensation reaction to obtain the dual-stimulus-responsive lipoic acid-based polymer shown in Formula I; the reaction formula is as shown below:

[0091] ;

[0092] wherein x≥1, y≥1, z≥1, and n is 20-60, preferably 44.

[0093] As an optional embodiment, the molar ratio of the Fmoc-GFLG and the IMDQ is 1: (1-1.2), for example, it can be 1:1, 1:1.05, 1:1.1, 1:1.15, 1:2, etc.

[0094] As an optional embodiment, in the process of preparing the Fmoc-GFLG-IMDQ, the temperature of the condensation reaction is 0-30℃, for example, it can be 0℃, 5℃, 15℃, 20℃, 25℃, 30℃, etc., and the time of the condensation reaction is 4-8 h, for example, it can be 4 h, 4.5 h, 5 h, 5.5 h, 6 h, 6.5 h, 7 h, 7.5 h, 8 h, etc.

[0095] As an optional embodiment, in the process of preparing the Fmoc-GFLG-IMDQ, the condensation reaction is carried out in the presence of a condensing agent, and the molar ratio of the Fmoc-GFLG and the condensing agent is 1: (1-2), for example, it can be 1:1, 1:1.2, 1:1.4, 1:1.5, 1:1.6, 1:1.8, 1:2, etc.

[0096] As an optional embodiment, in the process of preparing the Fmoc-GFLG-IMDQ, the condensing agent comprises any one or a combination of at least two of HBTU, HATU, HCTU, HOAT, HOBT, DIC, PyAOP or PyBOP, and preferably HBTU.

[0097] As an optional embodiment, in the process of preparing the Fmoc-GFLG-IMDQ, the condensation reaction is carried out in the presence of a base, and the molar ratio of the Fmoc-GFLG and the base is 1: (1-3), for example, it can be 1:1, 1:1.2, 1:1.4, 1:1.5, 1:1.6, 1:1.8, 1:2, 1:2.2, 1:2.4, 1:2.5, 1:2.6, 1:2.8, 1:3, etc.

[0098] As an optional embodiment, in the process of preparing the Fmoc-GFLG-IMDQ, the base comprises any one or a combination of at least two of DIPEA, TEA, Py, NMM, TMP, KOBu-t or NaOBu-t, and preferably DIPEA.

[0099] As an optional embodiment, the reagent used in the deprotection reaction is piperidine.

[0100] As an optional embodiment, the temperature of the deprotection reaction is 10-30°C, for example, it can be 10°C, 15°C, 20°C, 25°C, 30°C, etc., and the time of the deprotection reaction is 0.5-2 h, for example, it can be 0.5 h, 0.6 h, 0.8 h, 1 h, 1.2 h, 1.4 h, 1.6 h, 1.8 h, 2 h, etc.

[0101] As an optional embodiment, the temperature of the ring-opening polymerization reaction is 60-80°C, for example, it can be 60°C, 65°C, 68°C, 70°C, 72°C, 75°C, 80°C, etc., and the time of the ring-opening polymerization reaction is 1-2 h, for example, it can be 1 h, 1.2 h, 1.4 h, 1.5 h, 1.6 h, 1.8 h, 2 h, etc.

[0102] As an optional embodiment, the molar ratio of the lipoic acid, PEG-NH2 and GFLG-IMDQ is 1:(5-50):(1-10).

[0103] For example, the "5-50" can be 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, etc.

[0104] For example, the "1-10" can be 1, 2, 3, 4, 6, 7, 8, 9, 10, etc.

[0105] As an optional embodiment, the molar ratio of the lipoic acid (PTA) and polyethylene glycol (PEG) is 1:(5-50), for example, it can be 1:5, 1:6, 1:8, 1:12, 1:12, 1:14, 1:15, 1:16, 1:18, 1:20, 1:22, 1:24, 1:25, 1:30, 1:35, 1:40, 1:45, 1:50, etc., and more preferably 1:(10-20).

[0106] As an optional embodiment, the molar ratio of the polyethylene glycol grafted glutathione responsive lipoic acid (PTA-g-mPEG) and the TLR7 / 8 agonist imidazoquinoline peptide chain connected to cathepsin B (GFLG-IMDQ) is 1:(10-100), for example, it can be 1:10, 1:12, 1:14, 1:15, 1:16, 1:18, 1:20, 1:22, 1:24, 1:25, 1:26, 1:28, 1:30, 1:32, 1:34, 1:35, 1:36, 1:38, 1:40, 1:42, 1:44, 1:45, 1:46, 1:48, 1:50, 1:60, 1:70, 1:80, 1:90, 1:100, etc., and more preferably 1:(20-40).

[0107] In the present application, the source of the GFLG polypeptide is not limited, which can be commercially available or synthesized by oneself.

[0108] As an optional embodiment, in the condensation of the lipoic acid, PEG-NH2 and GFLG-IMDQ, the temperature of the condensation reaction is 0-30℃, for example, it can be 0℃, 5℃, 15℃, 20℃, 25℃, 30℃, etc., and the time of the condensation reaction is 4-8 h, for example, it can be 4 h, 4.5 h, 5 h, 5.5 h, 6 h, 6.5 h, 7 h, 7.5 h, 8 h, etc.

[0109] As an optional embodiment, in the condensation of the lipoic acid, PEG-NH2 and GFLG-IMDQ, the condensation reaction is carried out in the presence of a condensing agent, and the molar ratio of the lipoic acid and the condensing agent is 1:(1-3), for example, it can be 1:1, 1:1.2, 1:1.4, 1:1.5, 1:1.6, 1:1.8, 1:2, 1:2.2, 1:2.4, 1:2.5, 1:2.6, 1:2.8, 1:3, etc.

[0110] As an optional embodiment, in the condensation of the lipoic acid, PEG-NH2 and GFLG-IMDQ, the condensing agent comprises any one or a combination of at least two of HBTU, HATU, HCTU, HOAT, HOBT, DIC, PyAOP or PyBOP, and preferably HBTU.

[0111] As an optional embodiment, in the condensation of the lipoic acid, PEG-NH2 and GFLG-IMDQ, the condensation reaction is carried out in the presence of a base, and the molar ratio of the lipoic acid and the base is 1:(1-5), for example, it can be 1:1, 1:1.2, 1:1.4, 1:1.5, 1:1.6, 1:1.8, 1:2, 1:2.2, 1:2.4, 1:2.5, 1:2.6, 1:2.8, 1:3, 1:3.5, 1:4, 1:4.5, etc.

[0112] As an optional embodiment, in the condensation of the lipoic acid, PEG-NH2 and GFLG-IMDQ, the base comprises any one or a combination of at least two of DIPEA, TEA, Py, NMM, TMP, KOBu-t or NaOBu-t, and preferably DIPEA.

[0113] In a third aspect, the present application provides a dual-stimulus-responsive nano-delivery system, which comprises the dual-stimulus-responsive lipoic acid-based polymer as shown in formula I of the first aspect.

[0114] The application provides a high-efficiency and precise dual-stimulus responsive nano delivery system, which is based on GSH-responsive PTA as a skeleton, and a cathepsin B-responsive peptide chain (GFLG) is connected with a TLR7 / 8 agonist IMDQ on the side chain to form a dual-stimulus responsive nano delivery system. The nanoparticles can accumulate at the injection site and effectively drain to the lymph nodes, thereby reducing the clearance of the circulatory system and prolonging the aggregation time of IMDQ in the lymphatic tissue.

[0115] As an optional embodiment, the particle size of the dual-stimulus responsive nano delivery system is 50-500 nm, for example, can be 50 nm, 100 nm, 150 nm, 200 nm, 250 nm, 300 nm, 350 nm, 400 nm, 450 nm, 500 nm, etc., and preferably 50-200 nm.

[0116] As an optional embodiment, the dual-stimulus responsive nano delivery system further comprises dimethyl sulfoxide and water.

[0117] As an optional embodiment, in the dual-stimulus responsive nano delivery system, the concentration of the dual-stimulus responsive polythioctic acid polymer represented by formula I is 5-10 mg / mL, for example, can be 5 mg / mL, 6 mg / mL, 7 mg / mL, 8 mg / mL, 9 mg / mL, 10 mg / mL, etc., and preferably 6-8 mg / mL.

[0118] As an optional embodiment, the volume ratio of dimethyl sulfoxide to water is 1:(10-500), for example, can be 1:10, 1:20, 1:40, 1:50, 1:60, 1:80, 1:100, 1:120, 1:140, 1:150, 1:160, 1:180, etc., preferably 1:(10-200), and further preferably 1:(100-200).

[0119] In a fourth aspect, the application provides a preparation method of the dual-stimulus responsive nano delivery system according to the third aspect, and the preparation method comprises:

[0120] The dual-stimulus responsive polythioctic acid polymer represented by formula I is dissolved in dimethyl sulfoxide to obtain a dimethyl sulfoxide solution of the polymer;

[0121] The dimethyl sulfoxide solution of the polymer is added dropwise into water and stirred to obtain the dual-stimulus responsive nano delivery system.

[0122] As an optional embodiment, the temperature during the dropping process is controlled at 4-25℃, for example, it can be 4℃, 5℃, 6℃, 8℃, 10℃, 12℃, 14℃, 15℃, 20℃, 22℃, 24℃, 25℃, etc.

[0123] As an optional embodiment, the speed of stirring after the dropping process is controlled at 100-3000 rpm, for example, it can be 100 rpm, 200 rpm, 500 rpm, 1000 rpm, 1500 rpm, 2000 rpm, 2500 rpm, 3000 rpm, etc., preferably 1000-3000 rpm.

[0124] As an optional embodiment, the temperature of stirring after the dropping process is controlled at 4-25℃, for example, it can be 4℃, 5℃, 6℃, 8℃, 10℃, 12℃, 14℃, 15℃, 20℃, 22℃, 24℃, 25℃, etc.

[0125] As an optional embodiment, the speed of stirring after the dropping process is controlled at 100-3000 rpm, for example, it can be 100 rpm, 200 rpm, 500 rpm, 1000 rpm, 1500 rpm, 2000 rpm, 2500 rpm, 3000 rpm, etc., preferably 1000-3000 rpm.

[0126] As an optional embodiment, the time of stirring after the dropping process is controlled at 10-60 min, for example, it can be 10 min, 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, etc., preferably 30-60 min.

[0127] In a fifth aspect, the present application provides a use of the dual-stimulus-responsive polytaurine or the dual-stimulus-responsive nano-delivery system of the first aspect in the preparation of a tumor nano-drug therapeutic agent.

[0128] It should be noted that the present application provides a use of the dual-stimulus-responsive nano-delivery system of the above technical solution or the dual-stimulus-responsive nano-delivery system prepared by the preparation method of the above technical solution in the preparation of a therapeutic agent. The present application emphasizes the nano-agonist delivery system for tumor treatment, but is not limited to the field of tumor treatment, and can be applied according to the definition of the selected small molecule drug application field.

[0129] The prepared dual-responsive nanodelivery system can be effectively taken up by antigen presenting cells (APC) after being drained to lymph node tissue, the PTA backbone containing disulfide bonds is degraded by intracellular reducing GSH, and the nanoparticles gradually disintegrate. Subsequently, the GFLG polypeptide is degraded by cathepsin B, free IMDQ is released and stimulates the TLR7 / 8 receptor located on the intracellular membrane, and the body's immune system is activated. In addition, the nanosystem can realize tumor immunotherapy by loading different therapeutic molecules, and has a certain universality.

[0130] The application will be further described below by examples. Unless otherwise specified, the materials in the examples are prepared according to the existing method or directly purchased from the market.

[0131] Preparation Example 1

[0132] The preparation example provides a dual-stimulus-responsive polytaurine polymer, and a structural formula of the dual-stimulus-responsive polytaurine polymer is shown in formula I-1 as follows:

[0133]

[0134] Formula I-1;

[0135] In the above structural formula I-1, x:y:z is 44:1.5:15; the molecular weight of the polymer shown in formula I-1 is 45000 Da; wherein the molecular weight of the polyethylene glycol is 2000 Da; the molecular weight of the polytaurine is 15000 Da; wherein the drug loading of GFLG-IMDQ in the polymer is 10.89 μg / mg.

[0136] The preparation method of the dual-stimulus-responsive polytaurine polymer shown in formula I-1 provided by the preparation example comprises the following steps:

[0137] (a) Synthesis of GFLG-IMDQ:

[0138] A mixture of Fmoc-GFLG-OH (61.4 mg, 0.1 mmol) and IMDQ (39.5 mg, 0.11 mmol) is dissolved in anhydrous DMF. Then HBTU (56.9 mg, 0.15 mmol) and DIPEA (25.8 mg, 0.2 mmol) are dissolved in anhydrous DMF, and the mixture is added dropwise under stirring in an ice bath. The above mixture is stirred at room temperature for 6 h, and the crude product is purified by column chromatography (DCM / MeOH=100 / 0~90 / 10) to obtain Fmoc-GFLG-IMDQ.

[0139] Fmoc-GFLG-IMDQ was reacted with a mixture of piperidine / DCM (v / v = 20 / 80) for 1 h, and after removing the solvent by rotary evaporation, the filtrate was dropped into cold anhydrous ether to obtain GFLG-IMDQ as a precipitate.

[0140] (b) Synthesis of (PTA-g-mPEG)-GFLG-IMDQ

[0141] TA (5.00 g, 24.28 mmol) was added to a round-bottom flask, stirred at 70°C for 1.5 h, and the product was dissolved in 50.0 mL of DMF and slowly precipitated in 500 mL of ether for 3 times to obtain a sticky white solid. The ether was removed under vacuum to obtain dry PTA.

[0142] (c) A mixture of the obtained PTA (55 mg), GFLG-IMDQ (9.7 mg, 0.013 mmol) and PEG-NH2 (135 mg, 0.0675 mmol) was dissolved in anhydrous DMF.

[0143] Then HBTU (116.25 mg, 0.3 mmol) and DIPEA (52.2 mg, 0.405 mmol) were dissolved in anhydrous DMF and added dropwise to the mixture under stirring in an ice bath. The reaction mixture was stirred at room temperature for 6 h, dialyzed in a dialysis bag (MWCO 7000 Da) for 2 days, and further precipitated in cold ether, and dried to obtain the double-stimulus-responsive polyphosphatidylcholine polymer (PTA-mPEG-GFLG-IMDQ-1) represented by formula I-1.

[0144] The polymer PTA-mPEG-GFLG-IMDQ-1 was characterized: as shown in Figure 1 , the molecular structure was determined, proving that the double-stimulus-responsive polyphosphatidylcholine polymer represented by formula I was successfully prepared.

[0145] Preparation Example 2

[0146] This preparation example provides a double-stimulus-responsive polyphosphatidylcholine polymer, which is different from Preparation Example 1 only in that the molecular weight of the polyethylene glycol is 1000 Da, and the molecular weight of the polyphosphatidylcholine is 10000 Da, to obtain PTA-mPEG-GFLG-IMDQ-2, which is completely consistent with Preparation Example 1 in other structures.

[0147] Preparation Example 3

[0148] The present preparation example provides a double-stimulus-responsive polythioctic acid polymer, which is different from that of Preparation Example 1 only in that the molecular weight of the polyethylene glycol is 5000 Da, and the molecular weight of the polythioctic acid is 50000 Da, to obtain PTA-mPEG-GFLG-IMDQ-3, which is otherwise identical to that of Preparation Example 1.

[0149] Comparative Preparation Example 1

[0150] The present comparative preparation example provides a polythioctic acid polymer, which is not grafted with a polyethylene glycol group on the basis of Preparation Example 1, and the double-stimulus-responsive polythioctic acid polymer has the following structure shown in Formula II:

[0151]

[0152] Formula II.

[0153] Comparative Preparation Example 2

[0154] The present comparative preparation example provides a polythioctic acid polymer, which is not grafted with a GFLG-IMDQ group on the basis of Preparation Example 1, and the double-stimulus-responsive polythioctic acid polymer has the following structure shown in Formula III:

[0155]

[0156] Formula III.

[0157] Example 1

[0158] The present example provides a nano-delivery system containing a double-stimulus-responsive polythioctic acid polymer, which is prepared by the following steps:

[0159] (1) PTA-mPEG-GFLG-IMDQ-1 is dissolved in DMSO at a concentration of 0.1 mg / mL.

[0160] (2) Under stirring, water is slowly added dropwise to self-assemble into nanoparticles. The volume ratio of DMSO to water is 1:50, and the magnetic stirring speed is 80 rpm; wherein the dropping speed of the PTA-mPEG-GFLG-IMDQ-1 solution is 100 μL / min, and after the dropping is completed, the stirring is continued for 12 min.

[0161] Example 2

[0162] The present example provides a nano-delivery system containing a double-stimulus-responsive polythioctic acid polymer, which is prepared by the following steps:

[0163] (1) PTA-mPEG-GFLG-IMDQ-1 was dissolved in DMSO at a concentration of 0.05 mg / mL.

[0164] (2) Under stirring, water was slowly added dropwise to self-assemble into nanoparticles. The volume ratio of DMSO to water was 1:10, and the magnetic stirring speed was 50 rpm; wherein the dropping speed of PTA-mPEG-GFLG-IMDQ-1 solution was 50 μL / min, and stirring was continued for 10 min after the dropping was completed.

[0165] Example 3

[0166] This example provides a nano delivery system containing a double-stimulus-responsive polytaurine polymer, which is prepared by the following steps:

[0167] (1) PTA-mPEG-GFLG-IMDQ-1 was dissolved in DMSO at a concentration of 0.2 mg / mL.

[0168] (2) Under stirring, water was slowly added dropwise to self-assemble into nanoparticles. The volume ratio of DMSO to water was 1:100, and the magnetic stirring speed was 100 rpm; wherein the dropping speed of PTA-mPEG-GFLG-IMDQ-1 solution was 200 μL / min, and stirring was continued for 15 min after the dropping was completed.

[0169] Example 4

[0170] This example provides a nano delivery system containing a double-stimulus-responsive polytaurine polymer, which is different from Example 1 only in that PTA-mPEG-GFLG-IMDQ-1 is replaced by an equal amount of PTA-mPEG-GFLG-IMDQ-2, and other steps are completely consistent with Example 1.

[0171] Example 5

[0172] This example provides a nano delivery system containing a double-stimulus-responsive polytaurine polymer, which is different from Example 1 only in that PTA-mPEG-GFLG-IMDQ-1 is replaced by an equal amount of PTA-mPEG-GFLG-IMDQ-3, and other steps are completely consistent with Example 1.

[0173] Comparative Example 1

[0174] This example provides a nano delivery system, which is different from Example 1 only in that PTA-mPEG-GFLG-IMDQ-1 is replaced by an equal amount of the polymer represented by Formula II, and other steps are completely consistent with Example 1.

[0175] Comparative Example 2

[0176] This example provides a nano-delivery system, which is only different from Example 1 in that PTA-mPEG-GFLG-IMDQ-1 is replaced by the same amount of polymer shown in Formula III, and other steps are completely consistent with Example 1.

[0177] Test Example 1

[0178] Particle size test of the dual-responsive nano-delivery system

[0179] Test sample: the nano-delivery system provided by Examples 1-5, and the nano-delivery system provided by Comparative Examples 1-2.

[0180] Test method: the particle size and zeta potential of the prepared dual-responsive nano-delivery system are detected by using a nanoparticle size analyzer.

[0181] The test results are shown in Table 1 and Figure 2

[0182] Table 1

[0183]

[0184] As shown in Table 1 and Figure 2 , the experimental results show that the particle size of the nanoparticles prepared according to the above-mentioned ratio and compounding order of Example 1 is stable at 60-150 nm, and the zeta potential is -1-5 mV.

[0185] Test Example 2

[0186] In vitro enzyme-responsive release experiment of IMDQ

[0187] Test sample: the nano-delivery system provided by Examples 1-5, and the nano-delivery system provided by Comparative Examples 1-2.

[0188] Test method: first incubate the above sample in 25 μM DTT at 37°C overnight. Activate the cathepsin B in the activation buffer for 15 min, then add the above activated enzyme solution to the mixture of nanoparticles and assay buffer, and incubate at 37°C. At the predetermined time point, terminate the enzymolysis by adding the same volume of methanol. Then centrifuge the solution at 10000 rpm for 10 min, and detect the released IMDQ in the supernatant by HPLC (Agilent) at an absorbance of 322 nm. Chromatographic column: ZORBAX Eclipse Plus C8. Mobile phase: acetonitrile:0.3% acetic acid=10:90-90:10.

[0189] The specific test results are shown in Table 2 and Figure 3 ​As shown in Table 2 and

[0190] Table 2

[0191]

[0192] As shown in Table 3 and Figure 3 the experimental results show that (PTA-g-mPEG)-GFLG-IMDQ-1 has significant enzyme responsiveness and can release IMDQ in the presence of cathepsin B.

[0193] Test Example 3

[0194] In vitro DC maturation experiment

[0195] Test sample: the nano delivery system provided in Examples 1-5, and the nano delivery system provided in Comparative Examples 1-2.

[0196] Test method: 6-8 week old C57BL / 6 mice weighing about 20 g were purchased, and mouse bone marrow-derived DC cells (BMDC) were extracted. The BMDC were inoculated in a 24-well plate at a density of 1×10 5 per well, and the dual-responsive nanoparticles in the application were added, and incubated at 37°C. After 24 h of incubation, the BMDC were collected and the maturation (CD11c + CD80 + CD86 + ) of the BMDC was evaluated by flow cytometry.

[0197] The specific test results are shown in Table 3 and Figure 4

[0198] Table 3

[0199]

[0200] As shown in Table 3 and Figure 4 the experimental results show that (PTA-g-mPEG)-GFLG-IMDQ-1 nanoparticles can effectively stimulate the maturation of BMDC.

[0201] Test Example 4

[0202] Cytotoxicity test

[0203] Test sample: the nano delivery system provided in Examples 1-5, and the nano delivery system provided in Comparative Examples 1-2.

[0204] Cytotoxicity test: B16F10 cells were inoculated in a 96-well plate at a density of 1×10 4 ​Cells were seeded at a density in 96-well plates and cultured overnight. Different concentrations of reactivity-responsive nanoparticles were added to the cells. After 4 h of culture, the supernatant was removed, fresh culture medium was added, and 20 µL of thiazolyl blue solution (5 mg / mL) was added to each well. The cells were then cultured at 37°C for another 4 h. Dimethyl sulfoxide was added to dissolve the nanoparticles, and the absorbance of each well was measured at 450 nm. Cell viability was calculated using the following formula:

[0205] Cell viability (%) = (A sample / A blank) × 100.

[0206] The specific test results are shown in Table 4 and below. Figure 5 As shown:

[0207] Table 4

[0208]

[0209] As shown in Table 4 and Figure 5 As shown, the nanogene delivery system prepared according to the above method did not exhibit significant cytotoxicity and has good biocompatibility.

[0210] Test Example 5

[0211] In vivo safety testing

[0212] Test samples: the nanodelivery systems provided in Examples 1-5 and the nanodelivery systems provided in Comparative Examples 1-2.

[0213] Test method: C57BL / 6 mice weighing approximately 20 g and aged 6-8 weeks were purchased and subcutaneously injected with the dual-responsive nanoparticles of this invention. Whole blood was collected from the mice 3 hours after injection, and the blood supernatant was obtained by centrifugation at 3000 rpm for 10 min. Serum cytokine (IL-6 and IL-12) levels were measured using an ELISA kit.

[0214] The specific test results are shown in Table 5 below:

[0215] Table 5

[0216]

[0217] As shown in Table 5, the nanogene delivery system prepared by the above method has no obvious toxicity in vivo.

[0218] Test Example 6

[0219] Lymph node drainage test

[0220] Test samples: the nanodelivery systems provided in Examples 1-5 and the nanodelivery systems provided in Comparative Examples 1-2.

[0221] Test method: C57BL / 6 mice were subcutaneously injected with fluorescent probe-labeled (Cy7) dual-responsive nanoparticles and free Cy7. 24 h after injection, the fluorescence signal intensity of the inguinal lymph nodes was examined using an IVIS spectrum imaging system.

[0222] Specific test results are shown in Table 6 and Figure 6

[0223] Table 6

[0224]

[0225] As shown in Table 6 and Figure 6 , the results show that the dual-responsive nanoparticles can be effectively enriched in the lymph nodes of mice after subcutaneous injection.

[0226] Test Example 7

[0227] In vivo anti-tumor experiment

[0228] Test sample: Nanodelivery systems provided in Examples 1-5, and nanodelivery systems provided in Comparative Examples 1-2.

[0229] Test method: 6-8 week old C57BL / 6 mice weighing about 20 g were purchased, and log phase B16F10 cells were trypsinized, centrifuged at 1000 rpm for 5 min, and washed twice with PBS buffer. 2x10 6 cells per mouse were inoculated on the back of the mouse. After 5-6 days, when the tumor diameter grew to an average of 5 mm, the subsequent experiment was performed. Dual-responsive nanoparticles and control PBS were injected into the mouse body through the tail vein, and the amount and number of administrations were determined according to the tumor inhibition effect and the health status of the mouse, without specific requirements. After administration, the changes in tumor size and mouse weight were tracked, and the entire experiment was tracked for 15 days. Tumor volume (mm 3 ) = 0.5 x length (mm) x width (mm) 2 .

[0230] Specific test results are shown in Table 7:

[0231] Table 7

[0232]

[0233] As shown in Table 7, the results show that the tumor weight of the dual-responsive nanoparticle treatment group is 0.21 times that of the PBS group, and the dual-responsive nanoparticles can significantly inhibit the growth of melanoma.

[0234] ​To sum up, the dual-responsive nano delivery system prepared by the application can be taken by antigen presenting cells efficiently after being drained to lymph node tissue, the PTA backbone containing disulfide bond is degraded by intracellular reducing GSH, and the nanoparticles are gradually disintegrated. Subsequently, the GFLG polypeptide is degraded by intracellular cathepsin B, free IMDQ is released and stimulates TLR7 / 8 receptors located on the intracellular membrane, activates the body's immune system, and effectively inhibits tumor development. In addition, the nano system can have certain universality by loading different therapeutic molecules.

[0235] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the application, and not to limit them; although the application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the application.

Claims

1. A dual stimulus-responsive polymeric glutathione analogue, characterized in that, The dual-stimulus-responsive polytaurine polymer has the structure shown in Formula I. Formula I; Wherein, x≥1, y≥1, z≥1, n is 20-120.

2. The dual stimuli-responsive polythioic acid-based polymer according to claim 1, wherein The x:y:z is (30-140):(1-10):(5-50).

3. The dual stimuli-responsive polyhydrosulfuroximic acid polymer according to claim 1, wherein The molecular weight of the dual-stimulus-responsive polytaurine polymer is 20000-200000 Da.

4. The dual stimuli-responsive polythioic acid-based polymer of claim 1, wherein, The dual-stimulus-responsive polytaurine polymer comprises glutathione-responsive polytaurine, and the glutathione-responsive polytaurine has a polyethylene glycol group grafted at the carboxyl position and a TLR7 / 8 agonist imidazoquinoline covalently connected with a cathepsin B-responsive peptide chain; The molecular weight of the polyethylene glycol is 1000-5000 Da. The molecular weight of the polytaurine is 10000-50000 Da.

5. A method for preparing the dual stimuli-responsive polyhydrosulfuroximic acid polymer according to any one of claims 1 to 4, characterized by, The preparation method comprises the following steps: Fmoc-GFLG and IMDQ are subjected to condensation reaction to obtain Fmoc-GFLG-IMDQ; the Fmoc-GFLG-IMDQ is subjected to deprotection reaction to obtain GFLG-IMDQ; Taurine is subjected to ring-opening polymerization reaction to obtain polytaurine; The polytaurine, PEG-NH2 and GFLG-IMDQ are subjected to condensation reaction to obtain the dual-stimulus-responsive polytaurine polymer shown in Formula I.

6. The method for preparing the dual-stimulation responsive polythiooctanoic acid polymer according to claim 5, characterized in that, The molar ratio of the Fmoc-GFLG and IMDQ is 1:(1-1.2).

7. The method for preparing the dual-stimulation responsive polythiooctanoic acid polymer according to claim 5, characterized in that, In the process of preparing the Fmoc-GFLG-IMDQ, the condensation reaction is carried out at a temperature of 0-30℃ for 4-8 h.

8. The method for preparing the dual-stimulation responsive polythiooctanoic acid polymer according to claim 5, characterized in that, In the process of preparing the Fmoc-GFLG-IMDQ, the condensation reaction is carried out in the presence of a condensing agent, and the molar ratio of the Fmoc-GFLG and the condensing agent is 1:(1-2).

9. The method for preparing the dual-stimulation responsive polythiooctanoic acid polymer according to claim 5, characterized in that, In the process of preparing the Fmoc-GFLG-IMDQ, the condensation reaction is carried out in the presence of a base, and the molar ratio of the Fmoc-GFLG and the base is 1:(1-3).

10. The method for preparing the dual-stimulation responsive polythiooctanoic acid polymer according to claim 5, characterized in that, The deprotection reaction adopts piperidine as a reagent.

11. The method for preparing the dual-stimulation responsive polythiooctanoic acid polymer according to claim 5, characterized in that, The deprotection reaction is carried out at a temperature of 10-30℃ for 0.5-2 h.

12. The method for preparing the dual-stimulation responsive polythiooctanoic acid polymer according to claim 5, characterized in that, The ring-opening polymerization reaction is carried out at a temperature of 60-80℃ for 1-2 h.

13. The method for preparing the dual-stimulation responsive polythiooctanoic acid polymer according to claim 5, characterized in that, The molar ratio of the polytaurine, PEG-NH2 and GFLG-IMDQ is 1:(5-50):(1-10).

14. The method for preparing the dual-stimulation responsive polythiooctanoic acid polymer according to claim 5, characterized in that, In the process of condensing the polytaurine, PEG-NH2 and GFLG-IMDQ, the condensation reaction is carried out at a temperature of 0-30℃ for 4-8 h.

15. The method for preparing the dual-stimulation responsive polythiooctanoic acid polymer according to claim 5, characterized in that, In the process of condensing the polytaurine, PEG-NH2 and GFLG-IMDQ, the condensation reaction is carried out in the presence of a condensing agent, and the molar ratio of the polytaurine and the condensing agent is 1:(1-3).

16. The method for preparing the dual-stimulation responsive polythiooctanoic acid polymer according to claim 5, characterized in that, In the process of condensing the polytaurine, PEG-NH2 and GFLG-IMDQ, the condensation reaction is carried out in the presence of a base, and the molar ratio of the polytaurine and the base is 1:(1-5).

17. A dual stimuli-responsive nanodelivery system, characterized in that, The dual-stimuli responsive nanodelivery system comprises the dual-stimuli responsive polythioctic acid polymer according to any one of claims 1-4.

18. The dual stimuli-responsive nanodelivery system of claim 17, wherein, The dual-stimuli responsive nanodelivery system has a particle size of 50-500 nm.

19. The dual stimuli-responsive nanodelivery system of claim 17, wherein, The dual-stimuli responsive nanodelivery system further comprises dimethyl sulfoxide and water.

20. The dual stimuli-responsive nanodelivery system of claim 17, wherein, In the dual-stimuli responsive nanodelivery system, the concentration of the dual-stimuli responsive polythioctic acid polymer of formula I is 5-10 mg / mL.

21. The dual stimuli-responsive nanodelivery system of claim 19, wherein, The volume ratio of the dimethyl sulfoxide to water is 1:(10-500).

22. A method of preparing the dual stimuli-responsive nanodelivery system according to any one of claims 17-21, characterized by, The preparation method comprises: dissolving the dual-stimuli responsive polythioctic acid polymer of formula I in dimethyl sulfoxide to obtain a dimethyl sulfoxide solution of the polymer; adding the dimethyl sulfoxide solution of the polymer dropwise into water, and stirring to obtain the dual-stimuli responsive nanodelivery system.

23. The method of claim 22, wherein the dual stimuli-responsive nanodelivery system is prepared by, During the dropping process, the temperature is controlled to be 4-25°C; and the stirring speed is controlled to be 100-3000 rpm.

24. The method of claim 22, wherein the dual stimuli-responsive nanodelivery system is prepared by, After the dropping process, the stirring temperature is 4-25°C, the stirring speed is 100-3000 rpm, and the stirring time is 10-60 min.

25. Use of the dual-stimuli responsive polythioctic acid polymer according to any one of claims 1-4 or the dual-stimuli responsive nanodelivery system according to any one of claims 17-21 in the preparation of a tumor nanomedicine therapeutic agent.

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