Silicon-based drug delivery carrier, delivery system and preparation method thereof

Abstract

The invention discloses a silicon-based drug delivery carrier, a delivery system and a preparation method of the silicon-based drug delivery carrier, and relates to the technical field of medical preparations. The silicon-based drug delivery carrier comprises mesoporous silica nanoparticles and polydopamine wrapping the surfaces of the mesoporous silica nanoparticles; the sulfanilamide-quaternary ammonium type zwitterionic polymer and the galactosyl polymer are subjected to Michael addition reaction with the polydopamine through terminal amino groups to be modified on the surface of the polydopamine; the silicon-based drug delivery system comprises a drug delivery carrier and doxorubicin hydrochloride, and the doxorubicin hydrochloride is loaded in mesoporous silica nanoparticles of the drug delivery carrier. The silicon-based drug delivery system MSN-DOX (at) PDA-LB disclosed by the invention has the effects of dual targeting, dual promotion of tumor cell uptake and photothermal-chemotherapy synergistic anti-tumor; the technical problem of poor tumor treatment effect caused by poor stability, insufficient targeting, insufficient internalization utilization of tumor cells and single treatment mode of the existing nano drug-loaded preparation based on mesoporous silica nanoparticles can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of pharmaceutical formulations, and specifically relates to a silicon-based drug delivery carrier, a delivery system and a preparation method thereof. Background Art

[0002] With the aging of the population, cancer has become a very serious challenge. The progress of nanotechnology has provided new prospects for the treatment of cancer. In recent years, nanomedicine has been successfully applied to the treatment of cancer through the combination of nanotechnology and therapeutics. In the field of nanomedicine, nanocarriers play a key role in drug delivery, reducing serious side effects, simplifying the drug delivery regimen, and improving the therapeutic effect. Pure nanocarriers rely solely on passive diffusion to enter the tumor site, which results in a low degree of drug enrichment at the tumor site and an unsatisfactory therapeutic effect. In addition, in a large number of clinical practices and exploratory studies, it has been found that a single treatment method cannot eliminate the entire tumor and cannot effectively prevent the recurrence and metastasis of tumors. This may be because the complexity and heterogeneity of tumors cause the existence of tumor cell subsets resistant to a single therapy in tumor tissues. Therefore, designing nanocarriers that integrate multiple treatment methods and can precisely target tumors for efficient delivery of anticancer drugs is a current research hotspot.

[0003] Mesoporous silica nanoparticles (MSNs) are a class of porous SiO2 nanomaterials with pore sizes ranging from 2 to 50 nm. Due to their controllable morphology and size, they have become highly potential imaging and drug delivery carriers. Their unique mesoporous structure, large specific surface area and pore volume endow MSNs with the ability to efficiently load a variety of drugs. Whether it is small molecule drugs such as doxorubicin (DOX), camptothecin (CPT), cisplatin, or macromolecular drugs such as polypeptides, proteins, DNA, they can all be effectively loaded. In addition, compared with polymer nanoparticles, MSNs, as inorganic nanoparticles, have higher stability and biocompatibility, and their surfaces are easy to be chemically modified.

[0004] Currently reported nanodrug delivery systems based on MSNs, although they can respond to the tumor microenvironment to achieve controlled drug release and kill tumor cells, and inhibit tumor growth to a certain extent, have the following defects: (1) poor stability and short blood circulation time; (2) poor targeting, low degree of enrichment at the tumor site, and insufficient uptake by tumor cells; (3) single treatment method. Therefore, it is of great significance to develop a nanodrug delivery system based on MSNs that combines multiple targeting with precise positioning, synergistic treatment of multiple therapies and can be effectively taken up by tumor cells. Summary of the Invention

[0005] In order to solve the technical problems in the prior art that the nano-drug delivery formulations based on mesoporous silica nanoparticles have poor stability, insufficient targeting, insufficient internalization and utilization by tumor cells, and a single treatment method resulting in poor tumor treatment effects, the present invention provides a silicon-based drug delivery carrier, a delivery system and a preparation method thereof.

[0006] In order to achieve the above object, the specific solution adopted by the present invention is: a silicon-based drug delivery carrier, including mesoporous silica nanoparticles and polydopamine wrapped on the surface of the mesoporous silica nanoparticles, and a sulfonamide-quaternary ammonium zwitterionic polymer and a galactosyl polymer are modified on the surface of the polydopamine through Michael addition reaction of the terminal amino group with the polydopamine.

[0007] A silicon-based drug delivery system, including the above drug delivery carrier and doxorubicin hydrochloride, and the doxorubicin hydrochloride is loaded into the mesoporous silica nanoparticles of the drug delivery carrier.

[0008] A preparation method of a silicon-based drug delivery system includes the following steps:

[0009] S1. Dispersing the mesoporous silica nanoparticles in a PBS buffer solution, adding an aqueous solution of doxorubicin hydrochloride, stirring under dark conditions at room temperature, and centrifuging and washing the precipitate to obtain an intermediate product MSN-DOX;

[0010] S2. Adding a Tris-HCl buffer solution and dopamine hydrochloride to the intermediate product MSN-DOX, stirring under dark conditions at room temperature, and centrifuging and washing the precipitate to obtain an intermediate product MSN-DOX@PDA;

[0011] S3. Adding a PBS buffer solution, a sulfonamide-quaternary ammonium zwitterionic polymer and a galactosyl polymer to the intermediate product MSN-DOX@PDA, stirring under dark conditions at room temperature, centrifuging and washing the precipitate, and freeze-drying to obtain the drug delivery system, and the drug delivery system is MSN-DOX@PDA-LB.

[0012] As a further optimization of the above technical solution, in step S1, the mass ratio of the mesoporous silica nanoparticles to doxorubicin hydrochloride is 1:1 to 1:4, and the concentration of doxorubicin hydrochloride in the aqueous solution of doxorubicin hydrochloride is 2 to 8 mg / mL.

[0013] As a further optimization of the above technical solution, in step S2, the mass ratio of MSN-DOX to dopamine hydrochloride is 1:1 to 1:3, and the concentration of dopamine hydrochloride is 2 to 6 mg / mL.

[0014] As a further optimization of the above technical solution, in step S3, the structural formula of the sulfonamide-quaternary ammonium zwitterionic polymer is:

[0015] The structural formula of the galactosyl polymer is as follows:

[0016] As a further optimization of the above technical solution, in step S3, the mass ratio of the intermediate MSN-DOX@PDA, the sulfonamide-quaternary ammonium type zwitterionic polymer, and the galactosyl polymer is 1:(0.7 - 3.5):(0.3 - 1.5).

[0017] As a further optimization of the above technical solution, the preparation method of the mesoporous silica nanoparticles is as follows: Mix cetyltrimethylammonium bromide, ethanol, and water, after ultrasonic treatment, adjust the pH of the solution system to 11 - 12 with ammonia water, add tetraethyl orthosilicate dropwise, and stir at 75 °C for hydrolysis reaction. After precipitation, centrifugation, washing, and drying, then calcine to remove cetyltrimethylammonium bromide to obtain mesoporous silica nanoparticles.

[0018] As a further optimization of the above technical solution, the molar ratio of tetraethyl orthosilicate, cetyltrimethylammonium bromide, ethanol, and water is 1:(0.1 - 0.2):(65 - 75):(1400 - 1600).

[0019] As a further optimization of the above technical solution, the calcination temperature is 500 - 600 °C, and the calcination time is 6 - 8 h.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. The silicon-based drug delivery system provided by the present invention uses physical adsorption to load the chemotherapeutic drug doxorubicin into the mesopores of mesoporous silica, and coats the mesoporous silica nanoparticles with polydopamine having good photothermal conversion ability to prevent premature leakage of doxorubicin. Further modify the surface of polydopamine with a sulfonamide-quaternary ammonium type zwitterionic polymer with pH-responsive charge reversible conversion and a galactosyl polymer that specifically recognizes tumor cells to obtain a silicon-based drug delivery system MSN-DOX@PDA-LB with dual targeting, dual promotion of tumor cell uptake, and photothermal-chemotherapy synergistic anti-tumor effect.

[0022] 2. The silicon-based drug delivery system provided by the present invention is neutral in the normal physiological environment due to the presence of sulfonamide-quaternary ammonium zwitterionic polymer, which can significantly prolong the blood circulation time in vivo. After reaching the tumor site, the sulfonamide-quaternary ammonium zwitterionic polymer responds to the slightly acidic environment and undergoes a charge inversion, passively targeting tumor cells and having an electrostatic interaction with tumor cells, accelerating the uptake of anti-tumor nanodrugs by tumor cells. Since the galactosyl polymer can specifically bind to the highly expressed receptor on the surface of tumor cells, actively targeting tumor cells, receptor-mediated endocytosis promotes the uptake of the drug delivery system by tumor cells. The present invention's dual active and passive targeting of tumor cells, and the synergistic dual promotion of tumor cell uptake by electrostatic interaction and receptor-mediated endocytosis significantly improve the anti-tumor effect.

[0023] Meanwhile, in the present invention, the sulfonamide-quaternary ammonium zwitterionic polymer and the galactosyl polymer are simultaneously modified on polydopamine. Compared with MSN-DOX@PDA, the increase in the fluorescence intensity of MSN-DOX@PDA-LB is greater than the sum of the increases in the fluorescence intensities of separately loaded PLA (i.e., MSN-DOX@PDA-PLA) and separately loaded PBA (i.e., MSN-DOX@PDA-PBA). The simultaneous loading of PLA and PBA has a mutually promoting effect, significantly promoting the uptake of the nanocarrier by tumor cells. Compared with MSN-DOX, the increase in the killing effect of MSN-DOX@PDA-LB on liver cancer cells is greater than the sum of the increases in the killing effects of separately loaded PBA (i.e., MSN-DOX@PDA-PBA) and separately loaded PLA (i.e., MSN-DOX@PDA-PLA), producing an unexpected technical effect when polydopamine is simultaneously modified with the sulfonamide-quaternary ammonium zwitterionic polymer and the galactosyl polymer. This is mainly because the sulfonamide-quaternary ammonium zwitterionic polymer is electrically neutral at physiological pH and forms an anti-fouling layer through highly hydrated action, reducing the non-specific adsorption of proteins in the blood. This protects the galactosyl polymer from biomolecular shielding and maintains its binding ability to the ASGPR receptor on the surface of liver cancer cells. At the same time, the active targeting of the galactosyl polymer enriches the nanoparticles at the tumor site, ensuring the stability of the charge flipping behavior of the sulfonamide-quaternary ammonium zwitterionic polymer. This spatially confined charge flipping reduces the adsorption to normal cell tissues and enhances the permeability of the tumor cell membrane.

[0024] The number of receptors on the cell surface that specifically bind to PLA is fixed. That is, relying solely on the promotion of PLA on endocytosis is also limited. PBA is a passive targeting effect. Passive targeting preparations can only utilize the physiological structural characteristics of specific tissues and organs to achieve a natural distribution difference of drugs in the body to realize the targeting effect. This means that relying solely on the electrostatic interaction between the zwitterionic polymer with pH-responsive charge inversion and tumor cells is insufficient to promote the cellular uptake of the nano-drug carrier. While simultaneously loading PBA and PLA can complement each other, enabling more effective cellular uptake of the nanoparticles, thus leading to a more effective release of DOX.

[0025] 3. Due to the presence of the polydopamine coating layer in the silicon-based drug delivery system provided by the present invention, the loaded drug can stably exist in the carrier. The sulfonamide-quaternary ammonium type zwitterionic polymer endows mesoporous silica with excellent anti-fouling ability in the normal physiological environment, prolonging the blood circulation time. The sulfonamide-quaternary ammonium type zwitterionic polymer and the polydopamine coating layer synergistically enhance the drug stability and synergistically achieve an extended in vivo circulation time of the drug. In the environment with a lower pH inside tumor cells, the polydopamine coating layer undergoes cleavage to achieve the controlled and sustained release of the drug, enhancing the anti-tumor effect. The polydopamine coating layer has excellent photothermal conversion efficiency. After the drug delivery system accumulates at the tumor site, the heat generated under near-infrared light irradiation raises the temperature to the temperature for tumor thermal ablation, realizing the synergy of photothermal therapy and chemotherapy and achieving a significant therapeutic effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is the schematic diagram of the function of Example 1 of the present invention;

[0027] Figure 2 is the 1H NMR spectrum of the zwitterionic polymer and the glycopolymer prepared in the present invention;

[0028] Figure 3 is the transmission electron microscope image and particle size distribution diagram of MSN and MSN@PDA-LB prepared in the present invention;

[0029] Figure 4 is the dark-field transmission electron microscope image and the corresponding element distribution diagram of MSN@PDA-LB prepared in the present invention;

[0030] Figure 5 is the comparison diagram of the surface potential change performance of MSN and MSN@PDA-LB prepared in the present invention under different pH conditions;

[0031] Figure 6 is the stability test diagram of MSN@PDA-LB prepared in the present invention in different solution environments;

[0032] Figure 7Biocompatibility test chart of MSN@PDA-LB prepared according to the present invention;

[0033] Figure 8 Hemolysis performance test chart of MSN@PDA-LB prepared according to the present invention and MSN-DOX@PDA-LB prepared in Example 1;

[0034] Figure 9 Photothermal conversion performance test chart of MSN@PDA-LB prepared according to the present invention;

[0035] Figure 10 In vitro drug release characteristic test chart of MSN-DOX@PDA-LB prepared in Example 1 of the present invention;

[0036] Figure 11 In vitro cytotoxicity test chart of MSN-DOX@PDA-LB prepared in Example 1 of the present invention against tumor cells;

[0037] Figure 12 IC50 test chart of in vitro cytotoxicity of MSN-DOX@PDA-LB prepared in Example 1 of the present invention against tumor cells;

[0038] Figure 13 In vitro cellular uptake situation test chart of MSN-DOX@PDA-LB prepared in Example 1 of the present invention;

[0039] Figure 14 In vitro 3D tumor cell spheroid penetration performance test chart of MSN-DOX@PDA-LB prepared in Example 1 of the present invention. Detailed implementation manners

[0040] The technical solutions of the present invention will be further elaborated in detail below in conjunction with specific embodiments. For parts not detailedly recorded and disclosed in the following embodiments of the present invention, they should all be understood as the prior art known or should be known to those skilled in the art.

[0041] The present invention discloses a silicon-based drug delivery carrier, which includes mesoporous silica nanoparticles and polydopamine wrapped on the surface of the mesoporous silica nanoparticles. A sulfonamide-quaternary ammonium zwitterionic polymer and a galactosyl polymer are modified on the surface of the polydopamine through Michael addition reaction of the terminal amino group with the polydopamine.

[0042] The structural formula of the sulfonamide-quaternary ammonium zwitterionic polymer is:

[0043] The preparation method of the sulfonamide-quaternary ammonium zwitterionic polymer is:

[0044] Benzenesulfonamide (1.1 g, 7 mmol) was dispersed in 45 mL of toluene. The mixture was heated and stirred at 110 °C under a nitrogen atmosphere. After it was completely dissolved, bromoacetyl bromide (2.2 mL) was slowly added dropwise to the mixture. After reacting for another 5 h, heating was removed, and the mixture was left to stand at -20 °C for 24 h. The resulting precipitate was filtered, washed, and dried under vacuum to obtain the product 2-bromo-N-(phenylsulfonyl)acetamide (BSPA). BSPA (400 mg, 1.44 mmol), 2-(dimethylamino)ethyl methacrylate (DMAEMA) (800 mg, 5.09 mmol), and 4-methoxyphenol (MEHQ) (8 mg, 0.064 mmol) were dissolved in 3 mL of deionized water, and the reaction was carried out at 70 °C for two days under stirring. After purification by column chromatography, the product BSPAD was obtained.

[0045] BSPAD (520 mg, 1.46 mmol), 2-(aminoethyl) methacrylate hydrochloride (AEHM) (66.52 mg, 0.40 mmol), 4-cyano-4-(thiobenzoylthio) pentanoic acid (11.17 mg, 0.04 mmol), ACVA (2.8 mg, 0.01 mmol), and 3 mL of methanol were mixed in a Schlenk tube, and freeze-thaw degassing and deoxidation were carried out for three cycles. Then, the solution was polymerized at 70 °C for 24 h under a nitrogen atmosphere. The mixture was dialyzed in deionized water using a dialysis bag with a molecular weight cut-off of 2000 for 3 d and freeze-dried to obtain the polymer P(BSPAD-co-AEHM) (i.e., the sulfonamide-quaternary ammonium zwitterionic polymer PBA).

[0046] The structural formula of the galactosyl polymer is:

[0047] The preparation method of the galactosyl polymer is:

[0048] EDA (11 mL) and 85 mL of isopropanol were mixed in a beaker, and 31 mL of concentrated hydrochloric acid was added dropwise with stirring in an ice-water bath. After 1 h, the mixture was filtered and washed, and dried under vacuum to obtain EDA·2HCl. EDA·2HCl (15.00 g, 38.0 mmol) was dissolved in 75 mL of deionized water, and 8 mL of EDA solution was added. After stirring at room temperature for 30 min, it was stirred in an ice-water bath for another 30 min. Hydroquinone (10.00 mg, 38.0 mmol) was dissolved in 40 mL of methanol and 34 mL of methacrylic anhydride, and was added dropwise to the above solution at 0 °C at a rate of 1 drop every 4 - 5 seconds. After complete addition, it was stirred at room temperature overnight in the dark. Then, 20 mL of concentrated hydrochloric acid was added dropwise to the mixture in an ice-water bath, and then stirred at room temperature for 30 min. After vacuum concentration, it was washed with acetone, filtered, and dried under vacuum to obtain the crude product. The crude product was further purified by recrystallization to obtain a purer AEMA, which was stored in the dark for the next step.

[0049] Lactic acid (5.08 g, 14.2 mmol) was dissolved in 80 mL of methanol, and continuous vigorous stirring was carried out to prevent sugar aggregation. Then 3 mL of trifluoroacetic acid was added, and the mixture was stirred at 55 °C overnight and then concentrated to complete dryness. After that, 50 mL of methanol was added again to completely dissolve it, 3 mL of trifluoroacetic acid was added, and the mixture was stirred at 55 °C for 1 - 2 h and then concentrated to complete dryness. The dissolution and concentration process was repeated three times. 75 mL of methanol containing 13 g of AEMA was added to the obtained lactide, and after complete dissolution, 12.3 mL of triethylamine was added, and the mixture was stirred at room temperature in the dark for 5 - 7 days. Then, 5 mL of methanol was added to the mixture solution to dissolve the unreacted AEMA completely, and the suspension was filtered, washed, and dried to obtain a pale white product LAEMA.

[0050] Using LAEMA and AEHM as monomers, 4,4'-azobis(4-cyanovaleric acid) (ACVA) as the initiator, and 4-cyano-4-(thiobenzoylthio)valeric acid as the chain transfer agent, the polymer P(LAEMA-co-AEHM) (i.e., the galactosyl polymer PLA) was prepared by RAFT polymerization.

[0051] The present invention also discloses a silicon-based drug delivery system, which includes the above-mentioned drug delivery carrier and doxorubicin hydrochloride, and doxorubicin hydrochloride is loaded in the mesoporous silica nanoparticles of the drug delivery carrier.

[0052] The preparation method of the silicon-based drug delivery system is as follows:

[0053] S1. Under ultrasonic assistance, the mesoporous silica nanoparticles were dispersed in a PBS buffer solution with a pH value of 7.4, and then an aqueous solution of doxorubicin hydrochloride was added. The mixture was stirred at room temperature in the dark for 4 - 12 h, and after centrifugation and washing the precipitate, the MSN loaded with DOX, that is, the intermediate product MSN-DOX, was obtained; among them, the mass ratio of the mesoporous silica nanoparticles to doxorubicin hydrochloride was 1:1 - 1:4, and the concentration of doxorubicin hydrochloride in the aqueous solution of doxorubicin hydrochloride was 2 - 8 mg / mL; the rotation speed of centrifugation was 10000 rpm - 12000 rpm, the time was 10 min - 20 min, and the precipitate was washed with ultrapure water.

[0054] The preparation method of the mesoporous silica nanoparticles is:

[0055] Cetyltrimethylammonium bromide, ethanol, and water were mixed. After ultrasonic treatment, the pH of the solution system was adjusted to 11 - 12 with ammonia water. Tetraethyl orthosilicate was added dropwise, and the hydrolysis reaction was carried out with stirring at 75 °C for 2 - 4 h. The precipitate was centrifuged and separated. The separated precipitate was washed twice and then dried, and then calcined to remove the template agent cetyltrimethylammonium bromide, thus obtaining mesoporous silica MSN. Among them, the molar ratio of tetraethyl orthosilicate, cetyltrimethylammonium bromide, ethanol, and water was 1:(0.1 - 0.2):(65 - 75):(1400 - 1600); the rotation speed of the precipitate centrifugation was 10000 rpm - 12000 rpm, the time was 10 min - 20 min, and the precipitate was washed with a solution of ethanol:water = 1:1; the calcination temperature was 500 - 600 °C, and the calcination time was 6 - 8 h.

[0056] S2. A 10 mM Tris - HCl buffer solution with a pH of 8.5 and dopamine hydrochloride were added to the intermediate product MSN - DOX, and stirred for 2 - 4 h under dark conditions at room temperature. After centrifuging and washing the precipitate, the intermediate product MSN - DOX@PDA was obtained. Among them, the rotation speed of centrifugation was 10000 rpm - 12000 rpm, the time was 10 min - 20 min, and the precipitate was washed with ultrapure water; the mass ratio of MSN - DOX to dopamine hydrochloride was 1:1 - 1:3, and the concentration of dopamine hydrochloride was 2 - 6 mg / mL.

[0057] S3. PBS buffer solution, sulfonamide - quaternary ammonium zwitterionic polymer, and galactosyl polymer were added to the intermediate product MSN - DOX@PDA, and stirred for 4 - 12 h under dark conditions at room temperature. The precipitate was centrifuged and washed, and then freeze - dried for 24 - 48 h, thus preparing the described drug delivery system, which was MSN - DOX@PDA - LB. Among them, the mass ratio of MSN - DOX@PDA, sulfonamide - quaternary ammonium zwitterionic polymer, and galactosyl polymer was 1:(0.7 - 3.5):(0.3 - 1.5); the rotation speed of the precipitate centrifugation was 10000 rpm - 12000 rpm, the time was 10 min - 20 min, and the precipitate was washed with ultrapure water.

[0058] The preparation method of the silicon - based drug delivery carrier is generally the same as that of the silicon - based drug delivery system, except that DOX is not loaded in the mesoporous silica nanoparticles of the silicon - based drug delivery carrier, and the specific preparation method will not be elaborated here.

[0059] Example 1

[0060] A preparation method of a silicon - based drug delivery system is carried out according to the following steps:

[0061] 1. Preparation of mesoporous silica nanoparticles (MSNs):

[0062] Weigh 225 mg of cetyltrimethylammonium bromide (CTAB) into a 250 mL round-bottom flask. Add 150 mL of distilled water and 22.5 mL of ethanol to the flask, and ultrasonically treat for 25 min. While stirring magnetically at 500 rpm, add ammonia water to adjust the pH of the solution to 11.5. Then raise the temperature to 75 °C, add 1.25 mL of tetraethyl orthosilicate (TEOS), and continue to stir at 75 °C for 2 hours for the hydrolysis reaction. After the reaction, let the product stand and cool to room temperature, centrifuge at 12,000 rpm for 10 min, and wash the precipitate 3 times with a 1:1 mixture of deionized water and ethanol. The precipitate is dried overnight in a vacuum drying oven at 60 °C and then placed in a muffle furnace and calcined at 550 °C for 6 h to obtain mesoporous silica nanoparticles MSNs.

[0063] 2. Preparation of drug-loaded mesoporous silica nanoparticles (MSN-DOX):

[0064] Weigh 15 mg of MSN and disperse it in 4.5 mL of PBS buffer solution (pH = 7.4), and ultrasonically treat for 15 min. Measure 3 mL of 5 mg / mL DOX aqueous solution and add it thereto, and stir at room temperature in the dark for 4 h (200 rpm). Then centrifuge (12,000 rpm, 10 min) to collect the precipitate, wash it with water, and repeat three times. Freeze-dry the precipitate for 24 h to obtain MSN-DOX.

[0065] 3. Preparation of polydopamine-coated drug-loaded mesoporous silica nanoparticles (MSN-DOX@PDA):

[0066] Weigh 20 mg of MSN-DOX and disperse it in 10 mL of Tris-HCl buffer solution (10 mM, pH = 8.5), add 20 mg of dopamine hydrochloride, and stir at room temperature in the dark for 2 h (200 rpm). Then centrifuge (12,000 rpm, 10 min) to collect the precipitate, wash it with water, and repeat three times. Freeze-dry the precipitate for 24 h to obtain MSN-DOX@PDA.

[0067] 4. Preparation of sulfonamide-quaternary ammonium zwitterionic polymer and galactosyl polymer-modified polydopamine-coated drug-loaded mesoporous silica nanoparticles (MSN-DOX@PDA-LB):

[0068] Weigh 20 mg of MSN-DOX@PDA and disperse it in 5 mL of PBS buffer solution (pH = 7.4). Add 14 mg of sulfonamide-quaternary ammonium zwitterionic polymer (PBA) and 6 mg of galactosyl polymer (PLA), and stir overnight (200 rpm) under dark conditions at room temperature. Then centrifuge (12,000 rpm, 10 min) to collect the precipitate, wash it with water, and repeat three times. Freeze-dry the precipitate for 24 h to obtain the silicon-based drug delivery system MSN-DOX@PDA-LB of the present invention.

[0069] Example 2

[0070] 1. Preparation of mesoporous silica nanoparticles (MSNs):

[0071] Weigh 225 mg of cetyltrimethylammonium bromide (CTAB) into a 250 mL round-bottom flask. Add 150 mL of distilled water and 22.5 mL of ethanol to the flask, and ultrasonically treat for 25 min. While stirring magnetically at 500 rpm, add ammonia water to adjust the pH of the solution to 11.5. Then heat up to 75 °C, add 1.25 mL of tetraethyl orthosilicate (TEOS), and continue to stir at 75 °C for 2 h for the hydrolysis reaction. After the reaction, let the product stand and cool to room temperature, centrifuge at 12,000 rpm for 10 min, and wash the precipitate 3 times with a 1:1 mixture of deionized water and ethanol. Dry the precipitate in a vacuum drying oven at 60 °C overnight and then put it into a muffle furnace and calcine at 600 °C for 7 h to obtain mesoporous silica nanoparticles MSNs.

[0072] 2. Preparation of drug-loaded mesoporous silica nanoparticles (MSN-DOX):

[0073] Weigh 15 mg of MSN and disperse it in 4.5 mL of PBS buffer solution (pH = 7.4), and ultrasonically treat for 15 min. Measure 3 mL of 8 mg / mL DOX aqueous solution and add it thereto, and stir at 200 rpm under dark conditions at room temperature for 4 h. Then centrifuge (12,000 rpm, 10 min) to collect the precipitate, wash it with water, and repeat three times. Freeze-dry the precipitate for 24 h to obtain MSN-DOX.

[0074] 3. Preparation of polydopamine-coated drug-loaded mesoporous silica nanoparticles (MSN-DOX@PDA):

[0075] Weigh 20 mg of MSN-DOX and disperse it in 10 mL of Tris-HCl buffer solution (10 mM, pH = 8.5), add 20 mg of dopamine hydrochloride, and stir at 200 rpm under dark conditions at room temperature for 2 h. Then centrifuge (12,000 rpm, 10 min) to collect the precipitate, wash it with water, and repeat three times. Freeze-dry the precipitate for 48 h to obtain MSN-DOX@PDA.

[0076] 4. Preparation of sulfonamide-quaternary ammonium zwitterionic polymer and galactosyl polymer modified polydopamine-coated drug-loaded mesoporous silica nanoparticles (MSN-DOX@PDA-LB):

[0077] Weigh 20 mg of MSN-DOX@PDA and disperse it in 5 mL of PBS buffer solution (pH = 7.4). Add 14 mg of sulfonamide-quaternary ammonium zwitterionic polymer (PBA) and 6 mg of galactosyl polymer (PLA), and stir overnight (200 rpm) at room temperature in the dark. Then centrifuge (12,000 rpm, 10 min) to collect the precipitate, wash it with water, and repeat three times. Freeze-dry the precipitate for 24 h to obtain the silicon-based drug delivery system MSN-DOX@PDA-LB of the present invention.

[0078] Example 3

[0079] 1. Preparation of mesoporous silica nanoparticles (MSNs):

[0080] Weigh 225 mg of cetyltrimethylammonium bromide (CTAB) into a 250 mL round-bottom flask. Add 150 mL of distilled water and 22.5 mL of ethanol to the flask, and ultrasonically treat for 25 min. Under magnetic stirring at 500 rpm, add ammonia water to adjust the pH of the solution to 11.5. Then raise the temperature to 75 °C, add 1.25 mL of tetraethyl orthosilicate (TEOS), and continue to stir at 75 °C for 2 h for hydrolysis reaction. Let the reaction product stand and cool to room temperature, centrifuge at 12,000 rpm for 10 min, and wash the precipitate 3 times with a 1:1 mixture of deionized water and ethanol. Dry the precipitate in a vacuum drying oven at 60 °C overnight and then put it into a muffle furnace and calcine at 500 °C for 8 h to obtain mesoporous silica nanoparticles MSNs.

[0081] 2. Preparation of drug-loaded mesoporous silica nanoparticles (MSN-DOX):

[0082] Weigh 15 mg of MSN and disperse it in 4.5 mL of PBS buffer solution (pH = 7.4), and ultrasonically treat for 15 min. Measure 3 mL of 2 mg / mL DOX aqueous solution and add it thereto, and stir at room temperature in the dark for 4 h (200 rpm). Then centrifuge (12,000 rpm, 10 min) to collect the precipitate, wash it with water, and repeat three times. Freeze-dry the precipitate for 24 h to obtain MSN-DOX.

[0083] 3. Preparation of polydopamine-coated drug-loaded mesoporous silica nanoparticles (MSN-DOX@PDA):

[0084] Weigh 20 mg of MSN-DOX and disperse it in 10 mL of Tris-HCl buffer solution (10 mM, pH = 8.5). Add 20 mg of dopamine hydrochloride and stir for 2 h (200 rpm) at room temperature in the dark. Then centrifuge (12,000 rpm, 10 min) to collect the precipitate, wash it with water three times repeatedly. Freeze-dry the precipitate for 36 h to obtain MSN-DOX@PDA.

[0085] 4. Preparation of sulfonamide-quaternary ammonium zwitterionic polymer and galactosyl polymer-modified polydopamine-coated drug-loaded mesoporous silica nanoparticles (MSN-DOX@PDA-LB):

[0086] Weigh 20 mg of MSN-DOX@PDA and disperse it in 5 mL of PBS buffer solution (pH = 7.4). Add 14 mg of sulfonamide-quaternary ammonium zwitterionic polymer (PBA) and 6 mg of galactosyl polymer (PLA), and stir overnight (200 rpm) at room temperature in the dark. Then centrifuge (12,000 rpm, 10 min) to collect the precipitate, wash it with water three times repeatedly. Freeze-dry the precipitate for 24 h to obtain the silicon-based drug delivery system MSN-DOX@PDA-LB of the present invention.

[0087] Example 4

[0088] A preparation method of a silicon-based drug delivery carrier, and the silicon-based drug delivery carrier is MSN@PDA-LB.

[0089] 1. Preparation of mesoporous silica nanoparticles (MSNs):

[0090] Weigh 225 mg of cetyltrimethylammonium bromide (CTAB) into a 250 mL round-bottom flask. Add 150 mL of distilled water and 22.5 mL of ethanol to the flask, and ultrasonically treat for 25 min. Under magnetic stirring at 500 rpm, add ammonia water to adjust the pH of the solution to 11.5. Then raise the temperature to 75 °C, add 1.25 mL of tetraethyl orthosilicate (TEOS), and continue to stir at 75 °C for 2 h for the hydrolysis reaction. Let the reaction product stand and cool to room temperature, centrifuge at 12,000 rpm for 10 min, and wash the precipitate 3 times with a 1:1 mixture of deionized water and ethanol. Dry the precipitate in a vacuum drying oven at 60 °C overnight and then put it into a muffle furnace and calcine at 550 °C for 6 h to obtain mesoporous silica nanoparticles MSNs.

[0091] 2. Preparation of polydopamine-coated mesoporous silica nanoparticles (MSN@PDA):

[0092] Weigh 20 mg of MSN and disperse it in 10 mL of Tris-HCl buffer solution (10 mM, pH = 8.5). Add 20 mg of dopamine hydrochloride and stir for 2 h (200 rpm) at room temperature in the dark. Then centrifuge (12,000 rpm, 10 min) to collect the precipitate, wash it with water three times repeatedly. Freeze-dry the precipitate for 24 h to obtain MSN@PDA.

[0093] 3. Preparation of sulfonamide-quaternary ammonium zwitterionic polymer and galactosyl polymer modified poly-dopamine coated drug-loaded mesoporous silica nanoparticles (MSN@PDA-LB):

[0094] Weigh 20 mg of MSN@PDA and disperse it in 5 mL of PBS buffer solution (pH = 7.4). Add 14 mg of sulfonamide-quaternary ammonium zwitterionic polymer (PBA) and 6 mg of galactosyl polymer (PLA), and stir overnight (200 rpm) at room temperature in the dark. Then centrifuge (12,000 rpm, 10 min) to collect the precipitate, wash it with water three times repeatedly. Freeze-dry the precipitate for 24 h to obtain the silicon-based drug delivery system MSN@PDA-LB of the present invention.

[0095] Comparative Example 1

[0096] Preparation of mesoporous silica nanoparticles (MSNs):

[0097] The preparation method of mesoporous silica nanoparticles (MSNs) in this comparative example is the same as step 1 of Example 1.

[0098] Comparative Example 2

[0099] Preparation of drug-loaded mesoporous silica nanoparticles (MSN-DOX):

[0100] The preparation method of drug-loaded mesoporous silica nanoparticles (MSN-DOX) in this comparative example is the same as step 2 of Example 1.

[0101] Comparative Example 3

[0102] Preparation of poly-dopamine coated drug-loaded mesoporous silica nanoparticles (MSN-DOX@PDA):

[0103] The preparation method of poly-dopamine coated drug-loaded mesoporous silica nanoparticles (MSN-DOX@PDA) in this comparative example is the same as step 3 of Example 1.

[0104] Comparative Example 4

[0105] Preparation of MSN-DOX@PDA-PLA:

[0106] First, prepare MSN-DOX@PDA according to step 3 of Example 1;

[0107] Secondly, weigh 20 mg of MSN-DOX@PDA and disperse it in 5 mL of PBS buffer solution (pH = 7.4). Add 6 mg of galactosyl polymer (PLA), and stir overnight (200 rpm) under dark conditions at room temperature. Then centrifuge (12,000 rpm, 10 min) to collect the precipitate, wash it with water three times repeatedly. Freeze-dry the precipitate for 24 h to obtain the silicon-based drug delivery system MSN-DOX@PDA-PLA.

[0108] Comparative Example 5

[0109] Preparation of MSN-DOX@PDA-PBA

[0110] First, prepare MSN-DOX@PDA according to the steps in Example 1;

[0111] Secondly, weigh 20 mg of MSN-DOX@PDA and disperse it in 5 mL of PBS buffer solution (pH = 7.4). Add 14 mg of sulfonamide-quaternary ammonium zwitterionic polymer (PBA), and stir overnight (200 rpm) under dark conditions at room temperature. Then centrifuge (12,000 rpm, 10 min) to collect the precipitate, wash it with water three times repeatedly. Freeze-dry the precipitate for 24 h to obtain the silicon-based drug delivery system MSN-DOX@PDA-PBA of the present invention.

[0112] Comparative Example 6

[0113] Preparation of MSN@PDA

[0114] First, prepare mesoporous silica nanoparticles (MSN) according to the steps in Example 1;

[0115] Secondly, weigh 20 mg of MSN and disperse it in 10 mL of Tris-HCl buffer solution (10 mM, pH = 8.5). Add 20 mg of dopamine hydrochloride, and stir for 2 h (200 rpm) under dark conditions at room temperature. Then centrifuge (12,000 rpm, 10 min) to collect the precipitate, wash it with water three times repeatedly. Freeze-dry the precipitate for 24 h to obtain MSN@PDA.

[0116] Result analysis:

[0117] (1) Characterize the prepared sulfonamide-quaternary ammonium zwitterionic polymer PBA and galactosyl polymer PLA by nuclear magnetic resonance hydrogen spectrum. As Figure 2 shown: The characteristic peaks of the nuclear magnetic resonance hydrogen spectrum correspond one by one to the corresponding hydrogen atoms of the polymer, confirming the successful synthesis of the sulfonamide-quaternary ammonium zwitterionic polymer PBA and galactosyl polymer PLA.

[0118] (2) The particle size and morphology of the prepared MSN and MSN@PDA-LB were tested by DLS and TEM. The results are as Figure 3 shown: Figure 3 In the figure, A represents the TEM image of MSN, B represents the particle size distribution diagram of MSN, C represents the TEM image of MSN@PDA-LB, and D represents the particle size distribution diagram of MSN@PDA-LB. It can be Figure 3 seen that the sizes of MSN@PDA-LB and MSN are 152.28±1.85 nm and 106.42±2.86 nm respectively, presenting a spherical structure with uniform morphology.

[0119] (3) TEM was used to assist in determining the element distribution of the prepared MSN@PDA-LB. The results are as Figure 4 shown. The element distribution shows that MSN@PDA-LB contains the corresponding C, N, O, S, and Si elements, proving the successful preparation of MSN@PDA-LB.

[0120] It should be noted that in MSN-DOX@PDA-LB, DOX is loaded into the mesopores of mesoporous silica, then coated with PDA, and PLA and PBA (i.e., LB) are modified on the PDA coating layer. From Figure 4 the successful preparation of the MSN@PDA-LB carrier, the feasibility of the carrier preparation method can be considered as the feasibility of the preparation of the drug delivery system MSN-DOX@PDA-LB, and the subsequent drug release, cytotoxicity, and cell uptake all indirectly prove the successful loading of DOX. The properties of the carrier do not change significantly after DOX loading, that is, the properties of MSN-DOX@PDA-LB and MSN@PDA-LB are similar.

[0121] (4) Determination of the pH-responsive charge reversal property of the silicon-based drug delivery system

[0122] The MSN@PDA-LB prepared in the example was dispersed in PBS buffer solutions with different pH values (pH 6.0 - 8.0), and MSN was used as a control group to measure the surface potential changes under different pH conditions. The results are as attached Figure 5 shown: When the pH changes from 8.0 to 5.4, the surface potential of MSN@PDA-LB increases from -18.34 mV to 15.11 mV. This is because when pH≈6.7, the protonation of the imine group in the sulfonamide-quaternary ammonium zwitterionic polymer PBA makes the surface potential of the carrier change from negative to positive. In contrast, there is no obvious change in the Zeta potential of the MSN group.

[0123] (5) Determination of the storage stability of the silicon-based drug delivery system

[0124] The MSN@PDA-LB prepared in the examples was respectively placed in water, PBS buffer solution, physiological saline and DMEM solution, and its size change was characterized by DLS to determine its structural stability. The test results are as follows Figure 6 shown: After culturing in different media for 7 days, the particle size of MSN@PDA-LB did not change significantly, indicating its excellent storage stability.

[0125] (6) Determination of the biocompatibility of the silicon-based drug delivery system

[0126] The MTT method was used to study the cytotoxicity of MSN@PDA-LB prepared in the examples on the L02 cell line to determine its biocompatibility. The test results are as follows Figure 7 shown: Even when the concentration reached 200 μg / mL, the cell survival rate after co-culture with MSN@PDA-LB was above 90% under both pH 7.4 and pH 6.5 conditions, indicating that MSN@PDA-LB has good biocompatibility. In addition, the live / dead staining method was used to more intuitively observe that under pH 7.4 and pH 6.5 conditions, the vast majority of L02 cells emitted green fluorescence, that is, most L02 cells remained alive after co-culture with MSN@PDA-LB, further confirming its biosafety.

[0127] (7) Determination of the hemolytic properties of the silicon-based drug delivery system

[0128] 200 μL of physiological saline solutions of MSN@PDA-LB and MSN-DOX@PDA-LB at different concentrations were mixed with 200 μL of 4% red blood cell (RBCs) solution. RBCs in the physiological saline solution were used as the negative control group, and RBCs in 0.1% tritonX-100 solution were used as the positive control group. After oscillating and incubating at 37 °C for 3 h, the mixture was centrifuged at 1500 rpm for 10 min, and 100 μL of the supernatant of each group was transferred to a 96-well plate. The absorbance of the supernatant was measured at 570 nm using an ELISA microplate reader (Bio-Rad). The hemolysis rate was calculated according to the following formula:

[0129]

[0130] The results are as Figure 8 shown that even when the concentration reached 200 μg / mL, the hemolysis rates of MSN@PDA-LB and MSN-DOX@PDA-LB were less than the international standard of 5%, proving that the silicon-based drug delivery system has good blood compatibility and good drug encapsulation effect.

[0131] (8) Determination of the photothermal properties of the silicon-based drug delivery system

[0132] MSN, MSN@PDA, and MSN@PDA-LB were dissolved in PBS buffer solution to prepare suspensions (100 μg / mL). Using PBS buffer solution as the blank control, they were respectively exposed to a laser of 1 W / cm 2 , and the change of temperature with time was detected. As shown in Figure 9 B, the PBS group and the blank MSN group as the control showed negligible temperature rise, while obvious temperature rise was observed in the MSN@PDA and MSN@PDA-LB groups, proving that the PDA coating layer could effectively convert near-infrared laser energy into heat, and further modification had little effect on its photothermal conversion ability.

[0133] MSN@PDA-LB was dissolved in PBS buffer solution to prepare suspensions with different concentrations (25, 50, 100, 200 μg / mL) and were respectively exposed to a laser of 1 W / cm 2 , and the change of temperature with time was detected. As shown in Figure 9 C, the higher the concentration of the suspension, the higher the temperature.

[0134] MSN@PDA-LB was dissolved in PBS buffer solution to prepare a suspension (100 μg / mL) and was respectively exposed to lasers of 0.25, 0.5, 1, 2 W / cm 2 , and the change of temperature with time was detected. As shown in Figure 9 D, the higher the laser intensity, the higher the temperature. The temperature change of the MSN@PDA-LB suspension can be adjusted by simply adjusting the concentration of the suspension and the laser power, which has the advantage of being able to precisely control the temperature of the tumor area, ensuring the maximum therapeutic effect and the minimum side effects.

[0135] The change of temperature with time of the MSN@PDA-LB suspension (100 μg / mL) was detected during 5 cycles of laser irradiation. As shown in Figure 9 E, the photothermal conversion performance of MSN@PDA-LB was almost unchanged and there was no obvious attenuation during the "on / off" cycle, indicating that MSN@PDA-LB had good photothermal conversion stability.

[0136] The above results show that MSN@PDA-LB has significant and effective photothermal conversion performance in vitro.

[0137] (9) Determination of in vitro drug release characteristics of silicon-based drug delivery systems

[0138] Dialysis bags containing MSN-DOX, MSN-DOX@PDA, and MSN-DOX@PDA-LB were respectively placed in buffer solutions with pH values of 7.4, 6.5, and 4.5 for dialysis. Samples were taken at preset time points and an equal amount of the corresponding buffer solution was added, and the analysis was carried out by ultraviolet-visible spectrophotometer. The results are shown in Figure 10As shown, in the MSN-DOX group, 70% of the drug was released within 4 hours. That is, relying solely on physical adsorption, the drug-loaded nanoparticles had poor stability and the drug was prone to leakage. In the MSN-DOX@PDA group, the rapid release of the drug was significantly delayed, and it showed a pH-dependent drug release characteristic. At pH = 4.5, 70% of the drug was released within 24 hours, proving that the drug-loaded nanoparticles could effectively control drug release after being taken up by tumor cells. The results of the MSN-DOX@PDA-LB and MSN-DOX@PDA groups were similar, indicating that the modification with galactosyl polymer and sulfonamide-quaternary ammonium zwitterionic polymer did not affect their drug release.

[0139] (10) Determination of in vitro anti-tumor effect of silicon-based drug delivery system

[0140] Using the MTT method, the cytotoxicity of MSN-DOX@PDA-LB prepared in the examples was studied against the HepG2 cell line under the conditions of pH = 6.5 and laser irradiation, and its anti-tumor effect was determined. The test results are as follows Figure 11 As shown: Each experimental group showed a DOX concentration-dependent cell killing effect. Compared with the free DOX group, the cell viability of the MSN-DOX@PDA-PLA group and the MSN-DOX@PDA-PBA group decreased. In addition to the killing effect of the photothermal effect of PDA on tumor cells, in the MSN-DOX@PDA-PLA group, the enhanced endocytosis of the drug-loaded nanoparticles was mediated by the overexpressed asialoglycoprotein receptor on the surface of hepatoma cells; while in the MSN-DOX@PDA-PBA group, due to the charge reversal of the sulfonamide-quaternary ammonium zwitterionic polymer PBA in response to acidic pH and the electrostatic interaction with tumor cells, the internalization and utilization of MSN-DOX@PDA-PBA were promoted.

[0141] It should be noted that the killing effect of MSN-DOX@PDA loaded with both PBA and PLA simultaneously was higher than the sum of the killing effects of loading PBA alone and loading PLA alone. This further illustrates the significance of this strategy of dual-targeting to promote cell uptake and the combined photothermal-chemotherapy for synergistic anti-tumor.

[0142] Specifically, as Figure 11 shown, under the conditions of pH = 6.5 and laser irradiation:

[0143] The cell viability of the FreeDOX group was 33.53%, that is, the killing effect on hepatoma cells was e = 66.47%;

[0144] The cell viability of the MSN-DOX@PDA group was 35.48%, that is, the killing effect on hepatoma cells was c = 64.52%

[0145] The cell viability of the MSN-DOX@PDA-PLA group was 27.37%, that is, the killing effect on liver cancer cells was a = 72.63%

[0146] The cell viability of the MSN-DOX@PDA-PBA group was 22.9%, that is, the killing effect on liver cancer cells was b = 77.1%

[0147] The cell viability of the MSN-DOX@PDA-LB group was 11.39%, that is, the killing effect on liver cancer cells was d = 88.61%.

[0148] (a - c)+(b - c)=(72.63 - 64.52)+(77.1 - 64.52)=20.69%

[0149] (d - c)=(88.61 - 64.52)=24.09%

[0150] That is, (a - c)+(b - c)<(d - c);

[0151] (a - e)+(b - e)=(72.63 - 66.47)+(77.1 - 66.47)=16.79%

[0152] (d - c)=(88.61 - 66.47)=22.14%

[0153] That is, (a - e)+(b - e)<(d - c).

[0154] Therefore, it can be seen that the killing effect of MSN-DOX@PDA loaded with PBA and PLA simultaneously is higher than the sum of the killing effects of PBA alone and PLA loaded alone. This is because the simultaneous loading of PBA and PLA can enable effective cellular uptake of the nanoparticles, resulting in the effective release of DOX. As is well known, the amount of receptors on the cell surface is certain, and the mediated endocytosis is also limited; PBA has a passive targeting effect. Passive targeting preparations can only utilize the physiological structural characteristics of specific tissues and organs to produce natural distribution differences of drugs in the body to achieve the targeting effect. This means that relying solely on the passive targeting of sulfonamide-quaternary ammonium amphoteric ion polymers with pH-responsive charge inversion, the tumor targeting of nano-drug carriers is insufficient.

[0155] (11) Determination of the IC50 value of the cytotoxicity of the silicon-based drug delivery system against tumor cells

[0156] According to the in vitro cytotoxicity test results of MSN-DOX@PDA-LB against tumor cells, the data was fitted and plotted using origin data processing software, as Figure 12 shown: Consistent with the cell viability test results Figure 1For the MSN-DOX@PDA-LB group, the IC50 value was the lowest, at 1.98 μg / mL.

[0157] (12) Determination of the tumor cell uptake of the silicon-based drug delivery system

[0158] The autofluorescence of doxorubicin (DOX) can reflect its distribution and relative dose in cells. The tumor cell uptake of the intelligent silicon-based drug delivery system was determined by detecting the fluorescence of DOX through a fluorescence inverted microscope. Specific operation: After Hepg2 cells were adhered overnight, they were co-incubated with MSN-DOX, MSN-DOX@PDA-PLA, MSN-DOX@PDA-PBA, and MSN-DOX@PDA-LB (the MSN carrier was labeled with FITC showing green fluorescence) in a medium with pH = 6.5 for 4 h. Then, DAPI was used to counterstain the cell nuclei, and the uptake effect was observed with a fluorescence inverted microscope. The test results are shown as follows: Figure 13 Compared with other groups, the green fluorescence (FITC) and red fluorescence (DOX) of the cells in the MSN-DOX group were weaker, indicating less uptake by tumor cells. Compared with the MSN-DOX group, the intensities of the red fluorescence (DOX) and green fluorescence (FITC) of MSN-DOX@PDA-PLA were enhanced. This is because the galactose-based polymer modified on the surface of MSN-DOX@PDA-PLA has an active targeting effect on hepatoma cells overexpressing asialoglycoprotein receptors, and receptor-mediated endocytosis enhances cell uptake. The fluorescence intensity of the cells in the MSN-DOX@PDA-PBA group was also relatively strong. This is because of the pH-responsive charge inversion property of the sulfonamide-quaternary ammonium zwitterionic polymer PBA. Under the acidic condition of pH = 6.5, the imine groups in PBA are protonated, making the surface charge of the nanoparticles change from negative to positive, enhancing the electrostatic interaction with the negatively charged tumor cell surface and promoting the internalization and utilization of the nanoparticles. Impressively, MSN-DOX@PDA-LB showed the most significant fluorescence intensity, and MSN-DOX@PDA-LB showed stronger fluorescence intensity than MSN-DOX@PDA-PLA and MSN-DOX@PDA-PBA, indicating that compared with the nanocarriers modified with a single polymer, the co-modification of the galactose-based polymer and the sulfonamide-quaternary ammonium zwitterionic polymer more significantly promoted the cell uptake of the nanocarrier.

[0159] To further detect the change in fluorescence intensity after simultaneously loading PLA and PBA, fluorescence quantitative analysis was performed on different groups.

[0160] For ease of description, the average fluorescence intensities of MSN-DOX, MSN-DOX@PDA-PLA, MSN-DOX@PDA-PBA, and MSN-DOX@PDA-LB were set as A, B, C, and D respectively. Specifically:

[0161] MSN-DOX: A = 82.866

[0162] MSN-DOX@PDA-PLA: B = 89.056

[0163] MSN-DOX@PDA-PBA: C = 101.838

[0164] MSN-DOX@PDA-LB: D = 119.46

[0165] (B - A) + (C - A) = (89.056 - 82.866) + (101.838 - 82.866) = 25.162

[0166] (D - A) = 119.46 - 82.866 = 36.594

[0167] (B - A) + (C - A) < (D - A)

[0168] The increase in fluorescence intensity of the MSN-DOX@PDA-LB group is greater than the sum of the fluorescence intensities of the loaded PLA and PBA, further indicating that when PDA is coated on MSN-DOX and PLA and PBA are loaded simultaneously, the simultaneous loading of PLA and PBA produces a mutual promotion effect, which more significantly promotes the uptake of the nanocarrier by tumor cells.

[0169] Due to the significant differences between monolayer cells and solid tumors, the results of cell uptake may not accurately reflect the in vivo tumor penetration effect. Therefore, 3D tumor cell spheroids were used to study the in vivo penetration of MSN-DOX@PDA-LB. The penetration results of the tumor cell spheroids after being co-mixed with the drug-loaded nanoparticles for 4 h are as follows Figure 14 shown: In the MSN-DOX@PDA-PLA group and the MSN-DOX@PDA-PBA group, due to the receptor-mediated endocytosis of the galactose-based polymer and the tumor cells and the electrostatic adsorption of the sulfonamide-quaternary ammonium zwitterionic polymer and the tumor cells, a certain degree of fluorescence appeared in the tumor spheroids after 4 h of co-culture. The effect is similar to that of the free DOX group. This is because the presence of the polydopamine PDA coating layer in the MSN-DOX@PDA-PLA group and the MSN-DOX@PDA-PBA group can prevent the leakage of DOX, but the cell uptake effect and penetration effect are not good. Notably, after 4 h of co-culture, the red fluorescence of the MSN-DOX@PDA-LB group spreads throughout the tumor cell spheroid, that is, MSN-DOX@PDA-LB can effectively penetrate the in vivo tumor site, which is consistent with its excellent cell uptake effect.

[0170] The polydopamine (PDA) coated on the mesoporous silica nanoparticles of the present invention is a mussel-inspired adhesion protein polymer that forms an adhesion coating on the surface of the mesoporous silica nanoparticles and has good biocompatibility and in vivo degradability. Its surface carries abundant catechol groups that can be used for further modification. Moreover, as an analogue of in vivo melanin, PDA also has broadband light absorption and efficient photothermal conversion ability. Coating MSNs with PDA can not only achieve the sustained and controlled release of the drugs loaded in MSNs, improve stability, but also realize the combination of photothermal therapy and chemotherapy, and can also be used as a mediating layer for further modification of other ligands.

[0171] The nanocarriers modified with sulfonamide-quaternary ammonium zwitterionic polymers exhibit long blood circulation and negligible accelerated blood clearance (ABC) phenomenon, improving the biocompatibility of the drug carriers. The modification of sulfonamide-quaternary ammonium zwitterionic polymers with pH-responsive charge reversible conversion enables the drug carriers to undergo surface charge conversion in the mildly acidic tumor microenvironment, endowing them with the ability of passive targeting of tumor cells and promoting cell internalization, thereby enhancing the accumulation and retention at the tumor site.

[0172] The unique functional galactosyl polymers in the present invention can provide specific binding to tumor receptors, stimulus-responsive degradation, and enhanced tissue penetration, all of which enable them to be increasingly used in drug delivery systems to improve drug delivery efficiency. The modification of polymers containing sugar structures can achieve the active targeting of drug carriers to tumor cells overexpressing the corresponding sugar receptors, and receptor-mediated endocytosis enhances the uptake of tumor cells, improving the therapeutic effect.

[0173] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the broadest scope consistent with the principles and novel features disclosed herein.

Claims

1. A silicon-based drug delivery carrier, characterized in that: It includes mesoporous silica nanoparticles and polydopamine wrapped on the surface of the mesoporous silica nanoparticles. Sulfonamide-quaternary ammonium zwitterionic polymer and galactosyl polymer are modified on the surface of polydopamine through Michael addition reaction of the terminal amino group with polydopamine.

2. A silicon-based drug delivery system, characterized in that: It includes the drug delivery carrier as described in Claim 1 and doxorubicin hydrochloride, and the doxorubicin hydrochloride is loaded inside the mesoporous silica nanoparticles of the drug delivery carrier.

3. The preparation method of the silicon-based drug delivery system according to claim 2, characterized in that, It includes the following steps: S1. Disperse the mesoporous silica nanoparticles in PBS buffer solution, add the aqueous solution of doxorubicin hydrochloride, stir under dark condition at room temperature, and after centrifuging and washing the precipitate, obtain the intermediate product MSN-DOX; S2. Add Tris-HCl buffer solution and dopamine hydrochloride to the intermediate product MSN-DOX, stir under dark condition at room temperature, and after centrifuging and washing the precipitate, obtain the intermediate product MSN-DOX@PDA; S3. Add PBS buffer solution, sulfonamide-quaternary ammonium zwitterionic polymer and galactosyl polymer to the intermediate product MSN-DOX@PDA, stir under dark condition at room temperature, centrifuge and wash the precipitate, and freeze-dry it to obtain the described drug delivery system, and this drug delivery system is MSN-DOX@PDA-LB.

4. The preparation method of a silicon-based drug delivery system according to claim 3, characterized in that, In step S1, the mass ratio of the mesoporous silica nanoparticles to doxorubicin hydrochloride is 1:1 to 1:4, and the concentration of doxorubicin hydrochloride in the aqueous solution of doxorubicin hydrochloride is 2 to 8 mg / mL.

5. The preparation method of a silicon-based drug delivery system according to claim 3, characterized in that, In step S2, the mass ratio of MSN-DOX to dopamine hydrochloride is 1:1 to 1:3, and the concentration of dopamine hydrochloride is 2 to 6 mg / mL.

6. The preparation method of a silicon-based drug delivery system according to claim 3, characterized in that, In step S3, the structural formula of the sulfonamide-quaternary ammonium zwitterionic polymer is: The structural formula of the galactosyl polymer is:

7. The preparation method of a silicon-based drug delivery system according to claim 3, characterized in that, In step S3, the mass ratio of the intermediate product MSN-DOX@PDA, sulfonamide-quaternary ammonium zwitterionic polymer and galactosyl polymer is 1:(0.7 to 3.5):(0.3 to 1.5).

8. The preparation method of a silicon-based drug delivery system according to claim 3, characterized in that, The preparation method of the mesoporous silica nanoparticles is: mix cetyltrimethylammonium bromide, ethanol and water, after ultrasonic treatment, adjust the pH of the solution system to 11 to 12 with ammonia water, dropwise add tetraethyl orthosilicate, stir at 75 °C for hydrolysis reaction, centrifuge and wash the precipitate and then dry it, and then calcine to remove cetyltrimethylammonium bromide to obtain the mesoporous silica nanoparticles.

9. The preparation method of a silicon-based drug delivery system according to claim 8, wherein, The molar ratio of tetraethyl orthosilicate, cetyltrimethylammonium bromide, ethanol and water is 1:(0.1 to 0.2): (65～75)：(1400～1600)。 10. The preparation method of a silicon-based drug delivery system according to claim 8, wherein, The calcination temperature is 500 to 600 °C, and the calcination time is 6 to 8 h.

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