A DNA delivery vector

Abstract

The present application relates to the technical field of DNA delivery carrier, and specifically discloses a DNA delivery carrier for loading DNA and realizing targeted delivery, which is formed by electrostatic adsorption polymerization of chitosan quantum dots (CQDs) and polypyrrole (PPy), the carrier (CQDs / PPy) is soluble in water and forms stable nanoparticles in aqueous solution. The present application innovatively combines CQDs with polypyrrole (PPy) to construct a multifunctional gene delivery system with fluorescence tracking and pH / photothermal dual-responsive controlled release capability. The system combines the high gene loading and fluorescence tracking capability of CQDs with the photothermal conversion characteristics of PPy, realizes the visualization and accurate control of the gene delivery process, and under the conditions of pH=5.0 and near-infrared (NIR) irradiation, the DNA release rate of CQDs / PPy / DNA is more than 80%, the transfection efficiency in 293T and HeLa cells is 54.96% and 48.93% respectively, the cytotoxicity is significantly reduced, and after 4 minutes of near-infrared irradiation, the transfection efficiency is increased by 24%.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of DNA delivery carrier, in particular to a DNA delivery carrier. BACKGROUND

[0002] Gene therapy refers to the introduction of exogenous normal genes into target cells to correct or compensate for diseases caused by defective and abnormal genes, so as to achieve the purpose of treatment. It also includes the application of transgenic technology, that is, inserting exogenous genes into the appropriate recipient cells of patients through gene transfer technology, so that the products produced by the exogenous genes can treat certain diseases.

[0003] As a revolutionary treatment method, the clinical efficacy of gene therapy depends largely on safe and effective gene delivery systems. Among various non-viral vectors, chitosan has attracted great attention due to its unique biological properties. The rich amino groups in the molecular chain of chitosan can be protonated under weakly acidic conditions, thereby forming stable complexes of negatively charged DNA through electrostatic interaction, which not only effectively protects nucleic acids from enzymatic degradation, but also promotes cell uptake and endosomal escape. However, under physiological pH conditions, traditional chitosan carriers still have some shortcomings:

[0004] (1) Poor solubility severely limits the efficiency of DNA delivery;

[0005] (2) Lack of targeting ability makes it difficult to achieve precise tissue-specific delivery;

[0006] (3) Difficult to monitor the distribution and metabolism of the carrier in real time;

[0007] Therefore, the present application provides a DNA delivery carrier. SUMMARY

[0008] In view of the shortcomings of the prior art, the present application provides a DNA delivery carrier. The method uses chitosan quantum dots (CQDs) prepared by a quantumization strategy, and then combines CQDs with polypyrrole (PPy) to construct a multifunctional gene delivery system. Compared with existing non-viral gene carriers and other gene carriers with chitosan as the backbone, the present application solves the problem of low DNA delivery efficiency caused by low solubility of chitosan, and can monitor the distribution and metabolism of the carrier in real time. In addition, the pH sensitivity of chitosan and the photothermal properties of PPy also solve the targeting problem of the carrier.

[0009] To achieve the above object, the present application provides the following technical scheme: a DNA delivery carrier for loading DNA and realizing targeted delivery, which is polymerized by electrostatic adsorption of chitosan quantum dots (CQDs) and polypyrrole (PPy), the carrier (CQDs / PPy) is soluble in water and forms stable nanoparticles in aqueous solution.

[0010] Further, the particle size of the chitosan quantum dots (CQDs) is about 70-80 nm, and the particle size of the carrier (CQDs / PPy) is about 130-170 nm.

[0011] Further, the chitosan quantum dots (CQDs) are prepared by a hydrothermal method, which specifically includes the following steps:

[0012] S1, dispersing chitosan in an ice acetic acid solution and stirring to form a homogeneous colloid;

[0013] S2, performing hydrothermal reaction on the colloidal substance formed in step S2 to obtain a product solution containing chitosan quantum dots (CQDs);

[0014] S3, performing centrifugation and purification on the product solution containing chitosan quantum dots (CQDs) in step S2 to obtain a CQDs solution.

[0015] Further, the molecular weight of the chitosan is 1-50K, the amount is 1.5-3.9g, the concentration of the ice acetic acid is 0.35mol / L, the amount is 30-50mL, and the hydrothermal reaction time is 5-8h.

[0016] Further, the preparation method of the carrier (CQDs / PPy) includes the following steps:

[0017] S1, slowly adding pyrrole monomer to the CQDs solution under the action of an oxidizing agent, and stirring at room temperature for 24 hours;

[0018] S2, performing centrifugation and purification on the reaction product to obtain a CQDs / PPy solution.

[0019] Further, the oxidizing agent is ammonium persulfate, the amount is 0.5-3.2g, the amount of the pyrrole monomer is 0.03-0.1mL, and the amount of the chitosan quantum dots (CQDs) is 2-10mL.

[0020] The above carrier (CQDs / PPy) can be applied in gene therapy for efficient and controllable DNA delivery, which realizes targeted release through fluorescence tracing and pH / near-infrared dual response. The targeted release of DNA is realized under the conditions of tumor micro-acidic environment and near-infrared irradiation.

[0021] The application also provides a gene delivery system using the above-mentioned carrier, comprising the carrier (CQDs / PPy) and the DNA loaded thereon, wherein the DNA is plasmid DNA, and the carrier (CQDs / PPy) can completely condense the DNA when the mass ratio of the carrier (CQDs / PPy) to the DNA is 1:1. The gene delivery system can be applied in gene therapy, for improving the transfection efficiency of DNA and reducing cytotoxicity.

[0022] Compared with the prior art, the application has the following advantages:

[0023] (1) The chitosan is converted into CQDs through a quantum dot strategy, so that the water solubility and specific surface area of the chitosan are significantly improved, and the problem of low DNA delivery efficiency caused by poor solubility of traditional chitosan at physiological pH is overcome;

[0024] (2) The inherent fluorescence characteristics of CQDs endow the system with real-time tracing function, and the distribution and metabolic process (such as endocytosis path) of the carrier in cells can be dynamically monitored, so that the blank of real-time tracking in the prior art is filled;

[0025] (3) The pH responsiveness of chitosan and the photothermal responsiveness of PPy are combined to realize the dual regulation of “tumor micro-acidic environment-based release + light irradiation region explosive release”, so that the defects of traditional carriers, such as easy early release in physiological environment and lack of stimulus responsiveness, are solved. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The figure is a preparation scheme of the CQDs / PPy / DNA complex of the application and a transport schematic diagram of the complex in cells;

[0027] Figure 2 The figure is an infrared absorption spectrum diagram of Cs50k, Comparative Example 1, Comparative Example 2 and Example 1 of the application;

[0028] Figure 3 The figure is an AFM morphology data result diagram and a SEM scanning electron microscope diagram of Example 1 and Comparative Example 1 of the application;

[0029] Figure 4 The figure is an agarose gel electrophoresis test result diagram of Examples 1-3 of the application;

[0030] Figure 5 The figure is a test result diagram of the activity influence of different concentrations of Examples 1-3 of the application on HeLa cells;

[0031] Figure 6 The figure is a test result diagram of the activity influence of different concentrations of Cs50k, PPy, CQDs and Example 1 of the application on HeLa cells;

[0032] Figure 7Cell infection effect diagram of the present application examples 1-3, comparative example 1 and different samples of Cs50k;

[0033] Figure 8 Photothermal effect experiment diagram of the present application example 1. DETAILED DESCRIPTION

[0034] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0035] Preparation of the carrier (CQDs / PPy):

[0036] Example 1:

[0037] (1) 3.9g of chitosan 50k was dissolved in 50mL (0.35mol / L) of glacial acetic acid solution, and stirred at 60℃ to form a homogeneous colloid;

[0038] (2) The chitosan colloidal material obtained in step (1) was added to a polytetrafluoroethylene-lined high-pressure reaction kettle, and heated at 200℃ for 5h. After the reaction system was naturally cooled to room temperature, a product solution containing chitosan quantum dots (CQDs) was obtained;

[0039] (3) The product solution obtained in step (2) was centrifuged at a speed of 10000rpm / min for 15min to remove the precipitate with low fluorescence in the product solution, and then the supernatant was collected. The supernatant was further dialyzed in a dialysis bag with a molecular weight cut-off of 50000Da for 48-72h in the dark, and the dialysate was collected to obtain a CQDs solution;

[0040] (4) 2mL of the CQDs solution prepared in step (3) was mixed with 20mL of an aqueous solution containing 3.2g of ammonium persulfate, and 0.1mL of pyrrole monomer was slowly added thereto under magnetic stirring. After stirring at room temperature for 24h to make the reaction sufficient, the obtained mixture was centrifuged at 10000rpm / min for 30min, and the composite precipitate was collected. After repeated washing to remove unreacted monomers and oxidants, the composite precipitate was dispersed in deionized water to obtain a CQDs / PPy solution.

[0041] Comparative example 1: preparation of CQDs

[0042] Chitosan 50k (Cs50k) was dissolved in 50 mL (0.35 mol / L) glacial acetic acid, and stirred at 60 °C until a homogeneous colloid was formed. The mixture was then transferred to a polytetrafluoroethylene-lined autoclave, and hydrothermally reacted at 200 °C for 5 h. After the reaction system was naturally cooled to room temperature, the precipitate with lower fluorescence was removed by centrifugation at 6000 rpm / min for 15 min. The supernatant was collected, and the supernatant was dialyzed for 48 h in the dark. The dialysate was collected to obtain a CQDs solution.

[0043] Comparative Example 2: Preparation of PPy

[0044] 0.4 mL of pyrrole monomer was dissolved in 120 mL of deionized water, and an ammonium persulfate solution was slowly added thereto under stirring. The mixture was magnetically stirred at room temperature for 5 h. After the reaction was completed, the product was separated by vacuum filtration, and impurities were removed by washing with deionized water several times. After freeze-drying, a polypyrrole (PPy) powder was obtained.

[0045] The above Example 1, Comparative Example 1, Comparative Example 2, and Cs50k were subjected to infrared spectroscopy characterization analysis, as follows:

[0046] Cs50k, PPy, CQDs, CQDs / PPy, and potassium bromide were mixed at 1:100 (w / w) and ground, and then pressed into transparent thin circular pieces. An infrared spectrometer was used to collect spectra in the range of 400-4000 cm -1 The infrared characterization results are shown in Figure 2 As can be clearly seen, CQDs have a similar spectrum to Cs50k, retaining the main characteristic peaks of 3440 cm-1 (N-H and O-H stretching vibration), 2884 cm-1 (C-H stretching vibration), and 1045 cm-1 (C-O stretching vibration). CQDs / PPy retains the characteristic peaks of CQDs (a wide absorption peak of N-H stretching vibration at 3440 cm-1, and obvious C-H stretching vibration at 2884 cm-1 and C-O stretching vibration at 1045 cm-1), and also retains the main characteristic peaks of PPy (C=C stretching vibration at 1529 cm-1, and absorption peaks at 1458 cm-1 and 1172 cm-1, which are the plane deformation of C-N bond and C-H bond, respectively), proving the successful synthesis of CQDs / PPy.

[0047] The above Example 1 and Comparative Example 1 were subjected to AFM and SEM scanning electron microscope tests, and the results are shown in Figure 3 The AFM morphology data of CQDs are shown in Figure 3As shown in ab, at pH 5.0, CQDs exhibit a uniformly dispersed spherical structure with an average particle size of approximately 80 nm, consistent with the DLS test results. This indicates that the CQDs were successfully synthesized and possess excellent dispersibility, making them easily taken up by cells. The combined CQDs / PPy, as shown in ab, exhibits good dispersion. Figure 3 As shown in cd, the particle size increased to about 150 nm, but it still maintained good dispersibility and size uniformity. We speculate that during the pyrrole polymerization process, CQDs adsorbed with PPy through intermolecular forces, indicating that the introduction of PPy did not significantly destroy the structural stability of CQDs.

[0048] The microstructure and morphology of CQDs and CQDs / PPy were observed using SEM. The prepared sample aqueous solution was uniformly coated onto a silicon wafer, dried at room temperature, and then examined using a scanning electron microscope to obtain SEM images, such as... Figure 3 As shown in the figure, the morphological characteristics of the material were verified by SEM characterization. Figure 3 ef showed that at pH=5.0, CQDs exhibited regular spherical shapes under SEM, with smooth surfaces and no obvious agglomeration. The particle size distribution was consistent with the AFM results (80±10 nm). However, the surface roughness of CQDs / PPy increased, such as... Figure 3 As shown in gh, CQDs are uniformly distributed on the PPy surface with a particle size distribution of 150±20nm. The sample has good dispersion and relatively uniform size. SEM images further reveal that there is a tight binding between CQDs and PPy, and no obvious separation was observed. The above AFM and SEM results corroborate each other, proving that the sample was successfully prepared and that the sample has good dispersion and uniform size, making it easy for cells to take up.

[0049] Preparation of the carrier (CQDs / PPy):

[0050] Example 2:

[0051] (1) Dissolve 3g of chitosan 30k in 40mL (0.35mol / L) glacial acetic acid solution and stir at 60℃ until a homogeneous colloid is formed;

[0052] (2) Add the chitosan gel obtained in step (1) into a high-pressure reactor lined with polytetrafluoroethylene, heat it at 200°C for 6 hours, and after the reaction system cools naturally to room temperature, a product solution containing chitosan quantum dots (CQDs) is obtained.

[0053] (3) The product solution obtained in step (2) is centrifuged at 8000 rpm / min for 20 min to remove the precipitate with low fluorescence in the product solution. Then the supernatant is collected and further dialyzed in the dark for 48-72 h using a dialysis bag with a molecular weight cutoff of 30000 Da. The dialysate is collected to obtain CQDs solution.

[0054] (4) Take 5 mL of the CQDs solution prepared in step (3) and mix with 30 mL of an aqueous solution containing 1.6 g of ammonium persulfate, slowly add 0.05 mL of pyrrole monomer to it under magnetic stirring, stir at room temperature for 24 h to make the reaction sufficient, after the reaction is completed, centrifuge the obtained mixture at 10000 rpm / min for 30 min, collect the composite precipitate, repeatedly wash to remove unreacted monomer and oxidant, and then disperse in deionized water to obtain a CQDs / PPy solution.

[0055] Preparation of the carrier (CQDs / PPy):

[0056] Example 3:

[0057] (1) Take 1.5 g of chitosan 1k and dissolve in 30 mL (0.35 mol / L) of glacial acetic acid solution, and stir at 60°C to form a homogeneous colloid;

[0058] (2) Put the chitosan colloidal material obtained in step (1) into a polytetrafluoroethylene lined high-pressure reaction kettle, heat at 180°C for 8 h, and then cool the reaction system to room temperature naturally to obtain a product solution containing chitosan quantum dots (CQDs);

[0059] (3) Centrifuge the product solution obtained in step (2) at a speed of 5000 rpm / min for 25 min to remove the precipitate with low fluorescence in the product solution, then collect the supernatant, and further dialyze the supernatant in a dialysis bag with a molecular weight cut-off of 10000 Da for 48-72 h in the dark, collect the dialysate, and obtain a CQDs solution;

[0060] (4) Take 10 mL of the CQDs solution prepared in step (3) and mix with 25 mL of an aqueous solution containing 0.5 g of ammonium persulfate, slowly add 0.03 mL of pyrrole monomer to it under magnetic stirring, stir at room temperature for 24 h to make the reaction sufficient, after the reaction is completed, centrifuge the obtained mixture at 10000 rpm / min for 30 min, collect the composite precipitate, repeatedly wash to remove unreacted monomer and oxidant, and then disperse in deionized water to obtain a CQDs / PPy solution.

[0061] Carry out agarose gel electrophoresis experiments on Example 1, Example 2, and Example 3, and the specific process is as follows:

[0062] Add the carrier / DNA complex with different mass ratios to the 1% (w / v) agarose gel sample well containing EtBr, and place the gel in TBE buffer, electrophorese at a voltage of 90 V for 45 min, and observe the results using a gel imaging system to obtain the optimal mass combination ratio of the carrier / DNA. Figure 4The gel electrophoresis detection bands of CQDs / PPy obtained from Examples 1-3 and GFP plasmid with mass ratios of 0.5:1, 1:1, 1.5:1, 2:1 and 2.5:1 were detected, and bright bands were observed in the sample wells, indicating that CQDs / PPy can condense with DNA and make DNA stay in the wells. Example 1 can completely condense with DNA at a mass ratio of 1 / 1, and the binding capacity is better than that of Example 2 (1.5 / 1 can completely condense with DNA) and Example 3 (1 / 1 can completely condense with DNA), indicating that Example 1 has good DNA carrying capacity and can be used as an effective gene carrier.

[0063] The above Examples 1-3, Comparative Examples 1-2 and Cs50k were subjected to cytotoxicity experiments. Specifically, the MTT method was used to determine the effect of the samples on the growth state of HeLa cells, and the relative cell survival rate was used as the final evaluation basis. The cells were inoculated in a 96-well plate at an initial density of 1×10v, and the cells were incubated to 80% confluence. Then, the culture medium was replaced with complete culture medium containing various concentrations of the carrier for further incubation for 48 h. Each well was replaced with 100 μL of MTT (0.5 mg / mL) solution, and after 4 h, an equal amount of DMSO was used to dissolve the crystals. The relative cell survival rate was calculated by the formula: cell survival rate (%) = (A0-A1) / A0x100. The calculation data were averaged according to three measurement results, and the standard deviation was ±SD. Wherein A is the absorbance of cells incubated with various samples, A0 is the absorbance of cells incubated with complete culture medium, and A1 is the absorbance of blank wells containing complete culture medium and MTT solution without cells.

[0064] Figure 5 The effects of different concentrations of Examples 1-3 on the activity of HeLa cells, Figure 6 The effects of different concentrations of Cs50k, PPy, CQDs and Example 1 on the activity of HeLa cells were determined by Figure 5 The bar chart shows that the cytotoxicity of Example 1 is the lowest, because the amount of PPy used in Example 1 is more, which improves the safety of the complex. Through Figure 6 The bar chart shows that compared with single Cs50k, CQDs and Example 1, the cytotoxicity has a more obvious decrease, and the trend is more and more obvious with the increase of concentration in the set gradient range (5-25 mg / L), and the cell survival rate of the CQDs / PPy group can still be higher than 80% after reaching the maximum concentration, indicating that the introduction of PPy reduces the cytotoxicity of CQDs with strong positive charge, which is beneficial to subsequent cell experiments.

[0065] The cell transfection experiment was carried out on the above-mentioned examples 1-3, comparative example 1 and Cs50k. Specifically, the prepared carrier was mixed with plasmid DNA to form a complex, and the complex was incubated with HeLa cells at 37°C in a 5% CO2 incubator for 6h. Then, the culture medium was replaced with DMEM medium containing 10% serum, and the cells were incubated for another 48h. The expression of GFP was observed by inverted fluorescence microscope, and the cell transfection efficiency was quantitatively analyzed by flow cytometry. The results are shown in Figure 7 As shown in the figure, green fluorescent protein expression can be observed in HeLa cells treated with Cs5k / DNA, CQDs / DNA, and example / DNA complexes. However, the expression of fluorescent protein in example 1 is higher, indicating that the CQDs / PPy gene carrier prepared in the example can be used as an effective gene carrier for gene therapy.

[0066] In addition, in order to evaluate the photothermal effect of CQDs / PPy, the aqueous solution of CQDs / PPy in example 1 was continuously exposed to different power 808nm lasers, and the temperature change was detected by a thermal sensitive camera. As can be seen from Figure 8 under near-infrared 808nm laser irradiation, the higher the power, the higher the temperature of CQDs / PPy, which can reach the temperature required for tumor cell eradication. Subsequently, the temperature change of CQDs / PPy under different concentrations was studied, as shown in Figure 8 j, the results prove that there is a positive correlation between carrier concentration and temperature change. Under infrared 808nm laser irradiation, the temperature of CQDs remains relatively stable and does not reach the temperature required for killing tumor cells. This observation highlights the potential utility of CQDs / PPy in photothermal therapy.

[0067] In summary, in view of the three major limitations of chitosan carriers under physiological pH conditions, the present application aims to provide a DNA delivery carrier (CQDs / PPy) which is polymerized by electrostatic adsorption of chitosan quantum dots (CQDs) and polypyrrole (PPy). Compared with existing non-viral gene carriers and other gene carriers with chitosan as the skeleton, the present application innovatively combines CQDs with polypyrrole (PPy) to construct a multifunctional gene delivery system with fluorescence tracking and pH / photothermal dual-responsive controlled release capability. The system combines the high gene loading and fluorescence tracking capability of CQDs with the photothermal conversion property of PPy, achieving visualization and precise control of the gene delivery process. Under the conditions of pH=5.0 and near-infrared (NIR) irradiation, the DNA release rate of CQDs / PPy / DNA is more than 80%, the transfection efficiency in 293T and HeLa cells is 54.96% and 48.93% respectively, and the cytotoxicity is significantly reduced. After 4 minutes of near-infrared irradiation, the transfection efficiency is increased by 24%.

[0068] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting; it is not intended to exclude myriad other embodiments of the present application that other inventors can develop based on the same general inventive concepts embodied by the described embodiments. That is, although the present application is described in terms of particular embodiments and implementations, it is to be understood that the terminology used is for the purpose of descriptive clarity and that it is intended to be limited only by the words recited in the appended claims. It is to be understood that the terms "including", "comprising", "consisting" and variations thereof do not preclude the addition of further integers to the claimed combination of integers. It is to be understood that the terms "including", "comprising", "consisting" and variations thereof encompass the various features of the embodiments described herein, and are not restricted to the use of only the most preferred embodiments. It is further to be understood that the use of relational terms such as first and second, and the like, do not denote a physical or logical order or relationship among the various elements, but are used simply for distinguishing between various elements for clarity. It is to be understood that the terms "comprising", "including", and "having" and variations thereof are intended to be equivalent and open-ended, and include the various embodiments of the present application as recited in the claims. It is to be understood that the terms "including", "comprising", "consisting" and variations thereof encompass the various features of the embodiments described herein, and are not restricted to the use of only the most preferred embodiments. It is further to be understood that the use of relational terms such as first and second, and the like, do not denote a physical or logical order or relationship among the various elements, but are used simply for distinguishing between various elements for clarity. It is to be understood that the terms "comprising", "including", and "having" and variations thereof are intended to be equivalent and open-ended, and include the various embodiments of the present application as recited in the claims.

[0069] While the embodiments of the application have been shown and described herein, it is understood that modifications, substitutions, changes, and alterations can be made by those skilled in the art without departing from the spirit of the present application, which is defined by the appended claims and their equivalents.

Claims

1. A DNA delivery vector for loading DNA and achieving targeted delivery, characterized in that: The carrier is prepared by electrostatic adsorption polymerization of chitosan quantum dots (CQDs) and polypyrrole (PPy), and is soluble in water and forms stable nanoparticles in aqueous solution; when the mass ratio of the carrier and the DNA loaded thereon is 1:1, the DNA can be completely condensed.

2. The DNA delivery vector of claim 1, wherein: The chitosan quantum dots (CQDs) have a particle size of 70-80 nm, and the carrier has a particle size of 130-170 nm.

3. The DNA delivery vehicle of claim 2, wherein: The chitosan quantum dots (CQDs) are prepared by a hydrothermal method, and the preparation process comprises the following steps: S1, dispersing chitosan in an ice acetic acid solution and stirring until a homogeneous colloid is formed; S2, performing hydrothermal reaction on the colloidal substance formed in step S2 to obtain a product solution containing chitosan quantum dots (CQDs); S3, performing centrifugation and purification on the product solution containing chitosan quantum dots (CQDs) in step S2 to obtain a CQDs solution.

4. The DNA delivery vector of claim 3, wherein: The chitosan has a molecular weight of 1-50 K, and is used in an amount of 1.5-3.9 g; the ice acetic acid has a concentration of 0.35 mol / L, and is used in an amount of 30-50 mL; and the hydrothermal reaction time is 5-8 h.

5. The DNA delivery vehicle of claim 4, wherein: The preparation method of the carrier comprises the following steps: S1, slowly adding pyrrole monomers to the CQDs solution under the action of an oxidant, and stirring at room temperature for 24 hours; S2, performing centrifugation and purification on the reaction product to obtain a CQDs / PPy solution.

6. The DNA delivery vehicle of claim 5, wherein: The oxidant is ammonium persulfate, and is used in an amount of 0.5-3.2 g; the pyrrole monomers are used in an amount of 0.03-0.1 mL; and the chitosan quantum dots (CQDs) are used in an amount of 2-10 mL.

7. Use of the vector of any one of claims 1-6 in the preparation of a medicament for the treatment of a genetic disease. The carrier is used for efficient and controllable DNA delivery, and realizes targeted release through fluorescence tracing and pH / near-infrared dual response.

8. Use according to claim 7, characterized in that: The carrier realizes targeted release of DNA under the conditions of tumor micro-acidic environment and near-infrared irradiation.

9. A system for gene delivery using the vector of any one of claims 1-6, wherein: The carrier and the DNA loaded thereon are included.

10. Use of the gene delivery system of claim 9 for the preparation of a therapeutic gene medicine. The system is used for improving the transfection efficiency of DNA and reducing cell toxicity.

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