Gold nanoparticle / cisplatin double cross-linked polyamino acid hydrogel and preparation method and application thereof

Abstract

The application provides a gold nanoparticle / cisplatin double crosslinking polyamino acid hydrogel and a preparation method and application thereof, which is composed of a chemotherapeutic drug cisplatin, gold nanoparticles, a polyamino acid block polymer containing a carboxyl functional group and a terminal thiol or selenol and a solvent. The polyamino acid block polymer comprises cysteamine or selenocysteamine and a polyamino acid segment. The hydrogel firstly constructs amino acid modified gold nanoparticles through a sulfur-gold or selenium-gold bond; further, a semi-solid hydrogel is obtained by using the coordination of the carboxyl functional group and the cisplatin drug. The gold nanoparticles and the cisplatin drug are not only crosslinking agents for gel formation, but also functional components for realizing the photo-thermal and chemotherapy of the hydrogel. The hydrogel sustained-release preparation has in-vivo chloride ion responsive drug release, can maintain a relatively long effective drug concentration in the body, and has considerable application prospect for long-acting local treatment of cancer.

Description

Technical Field

[0001] This invention relates to the field of biomedical materials, specifically to a gold nanoparticle / cisplatin dual crosslinked polyamino acid hydrogel, its preparation method, and its applications. Background Technology

[0002] Cisplatin (CDDP) is a first-line anti-tumor drug with broad-spectrum anticancer activity. However, it has significant toxic side effects, easily causing nephrotoxicity, bone marrow suppression, and gastrointestinal side effects. Furthermore, cisplatin has a short half-life in the blood and low accumulation rate at lesion sites, limiting its clinical efficacy. Therefore, an effective and safe method of cisplatin administration is urgently needed for its clinical application.

[0003] Polymer hydrogels are systems composed of a three-dimensional network or interpenetrating network of molecular chains formed by cross-linking polymerization and a solvent (usually water), exhibiting significant physiological tissue-like properties. Due to their excellent designability and the ability to achieve sol-gel transitions under specific conditions, they hold great promise as drug delivery platforms for applications in biomedical fields such as tissue engineering and disease treatment.

[0004] Polyamino acids linked by peptide bonds exhibit good biocompatibility and biodegradability. Due to their structural similarity to natural proteins, polyamino acids can self-assemble into stable secondary structures such as α-helices or β-sheets in aqueous solutions, and can degrade into essential amino acids in vivo, with their metabolites being absorbed or metabolized by the body. Therefore, hydrogel carriers based on polyamino acids possess good biosafety.

[0005] However, traditional single-treatment methods still have relative limitations. Therefore, it is particularly important to conduct research on combination therapy using multiple modalities.

[0006] Gold nanoparticles are an important form of gold nanomaterials, ranging in size from a few nanometers to hundreds of nanometers. As an inert metal, gold nanoparticles are chemically stable and possess good photothermal properties. Furthermore, their excellent bioinertness and modifiability give these materials considerable potential for in vivo biomedical applications.

[0007] Here, we used cisplatin and gold nanoparticles as crosslinking points to form a novel double-crosslinked hydrogel with an amino acid block polymer. Summary of the Invention

[0008] The first objective of this invention is to address the shortcomings of existing technologies by providing a gold nanoparticle / cisplatin dual-crosslinked polyamino acid hydrogel. Compared to existing technologies, the drug-loaded hydrogel provided by this invention can significantly reduce drug release behavior; simultaneously, the introduction of gold nanoparticles, under near-infrared laser (1064nm) irradiation, provides local heat that amplifies the toxicity of cisplatin while simultaneously generating thermal ablation on the tumor, offering an effective solution for improving local treatment efficiency; furthermore, compared to existing gel materials, we use gold nanoparticles and cisplatin as crosslinking agents, simplifying material design and improving material utilization.

[0009] A gold nanoparticle / cisplatin dual crosslinked polyamino acid hydrogel includes cisplatin, gold nanoparticles, amino acid polymer and solvent, with the following composition ratio by mass percentage: gold nanoparticles 0.0039% to 0.031%, cisplatin 1% to 4%, amino acid polymer 2% to 20%, and the remainder being solvent;

[0010] The structure of the amino acid polymer is shown in formula (I):

[0011]

[0012] R1 is selected from -CH2- or -(CH2)2-; R2 is selected from -SH and -SeH; x is the degree of polymerization, 50≤x≤800.

[0013] Preferably, the gold nanoparticles have a mass percentage of 0.0085% to 0.015%.

[0014] Preferably, the amino acid polymer has a mass percentage of 2% to 8%.

[0015] Preferably, the cisplatin has a mass percentage of 1% to 3%.

[0016] Preferably, the solvent is water or phosphate buffer (PB buffer).

[0017] The polymer provided by this invention can be a polyamino acid material of formula (I) obtained by initiation with cystamine or selenocystamine.

[0018] A second objective of this invention is to provide a method for preparing the above-mentioned gold nanoparticle / cisplatin double-crosslinked polyamino acid hydrogel, comprising the following steps:

[0019] An amino acid polymer solution was prepared, fully dissolved at room temperature, and replaced with an N2 atmosphere. A gold nanoparticle solution was added, and the mixture was incubated in a shaker at 37°C. After being left exposed for a period of time, cisplatin was added and incubation continued to obtain the polyamino acid hydrogel.

[0020] Preferably, the mass ratio of the amino acid polymer, cisplatin, and gold nanoparticles is (200-500):(100-200):1.

[0021] A third objective of this invention is to provide the application of the above-mentioned polyamino acid hydrogel as a sustained-release carrier.

[0022] A fourth object of the present invention is to provide a combined drug comprising the above-described polyamino acid hydrogel and other drugs loaded on the polyamino acid hydrogel.

[0023] In the gel preparation process of this invention, cisplatin and gold nanoparticle crosslinking agents are introduced. The gold nanoparticles first undergo a sulfur-gold or selenium-gold coordination reaction with a polymer having the structure of formula (Ⅰ) in an aqueous medium to generate surface polyamino acid-modified gold nanoparticles; and the carboxyl groups on the surface coordinate with cisplatin again to form a drug-loaded hydrogel with gold nanoparticle-cisplatin double crosslinking.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] This invention uses functional components (gold nanoparticles with photothermal effects and the chemotherapy drug cisplatin) as gel crosslinking agents and hydrogel frameworks, simplifying the material design of the hydrogel. The prepared double-crosslinked hydrogel can significantly reduce the explosive release behavior of the drug. When irradiated with near-infrared laser (1064nm), the gel exhibits good photothermal properties. Cell experiments show that its toxicity is lower than that of the same dose of free drug, indicating the sustained-release function of the gel. This is of great significance for reducing the side effects caused by the initial explosive release of the drug and prolonging the duration of drug action.

[0026] The double crosslinked hydrogel prepared by this invention has good biodegradability, and its degradation cycle is 1 week. Attached Figure Description

[0027] Figure 1 The hydrogen nuclear magnetic resonance spectrum of PLG-SH prepared in Example 1 of this invention;

[0028] Figure 2 This is a transmission image of gold nanoparticles prepared in Example 5 of the present invention;

[0029] Figure 3 The near-infrared absorption spectrum of gold nanoparticles prepared in Example 5 of this invention;

[0030] Figure 4 The infrared spectra of PLG-SS-PLG, PLG-SH, and Au-S-PLG obtained in Example 6 of this invention are shown.

[0031] Figure 5The diagram shows the zeta potential changes of Au-CTAB, PLG-SH, and Au-S-PLG obtained in Example 7 of this invention.

[0032] Figure 6 The image shows the sol-gel transition of the double crosslinked hydrogel obtained in Example 7 of this invention.

[0033] Figure 7 The results of the rheological study of the double crosslinked hydrogel obtained in Example 8 of this invention;

[0034] Figure 8 This is a SEM microstructure image of the double crosslinked hydrogel obtained in Example 9 of the present invention;

[0035] Figure 9 The results of the MTT assay for sustained-release drug release from the dual-drug cross-linked hydrogel obtained in Example 1 of this invention are shown. Detailed Implementation

[0036] To further understand the present invention, preferred embodiments of the present invention are described below with reference to examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the claims of the present invention.

[0037] In a first aspect, the present invention provides a gold nanoparticle / cisplatin dual crosslinked polyamino acid hydrogel, comprising a cisplatin drug, gold nanoparticles, an amino acid polymer having the structure of formula (I), and a solvent.

[0038]

[0039] Where R1 is selected from -CH2-, -(CH2)2-; R2-SH, -SeH; x is the degree of polymerization, 50≤x≤800;

[0040] The composition of the hydrogel, expressed as a percentage by mass, is as follows:

[0041] 0.0039%–0.031% gold nanoparticles, 1%–4% cisplatin, 2%–20% amino acid polymers, the remainder being solvent.

[0042] The amino acid polymer having the structure of formula (I) was prepared by the following method:

[0043] γ-Benzyl-L-glutamate-N-lactalocarboxylic anhydride or β-Benzyl-L-aspartate-N-lactalocarboxylic acid is dissolved in a dry organic solvent, and nitrogen gas is introduced to obtain a first solution under a nitrogen atmosphere. Cystamine or selenocystamine is dissolved in an organic solvent, and nitrogen gas is introduced to obtain a second solution under a nitrogen atmosphere. The present invention does not impose any particular limitation on the concentration of the first solution. The present invention does not impose any particular limitation on the concentration of the second solution. The organic solvent is preferably dry N,N-dimethylformamide or dichloroethane, more preferably dry dichloroethane.

[0044] After obtaining the first and second solutions, the first and second solutions are mixed and stirred continuously under a nitrogen atmosphere. In the resulting mixed solution, the cystamine or selenocystamine undergoes a polymerization reaction with γ-benzyl-L-glutamate-N-lactalocarboxylic anhydride or β-benzyl-L-aspartate-N-lactalocarboxylic acid. The block polymer is obtained by sedimentation and filtration. The block polymer is redissolved in an organic solvent to obtain a third solution. An appropriate amount of acidic reagent is added to remove the protecting groups (benzyl ester groups) on the polyamino acid chains, and alkalization is performed to obtain alkalized carboxyl groups. The solid polymer is then obtained by sedimentation and filtration. The amino acid polymer is redissolved in deionized water, and an appropriate reducing agent is added to reduce the disulfide bonds or diselenyl bonds. After the reaction is complete, the mixture is dialyzed with deionized water under nitrogen protection and lyophilized to obtain the final product. The molar ratio of cystamine or selenocystamine to γ-benzyl-L-glutamate-N-lactalocarboxylic anhydride or β-benzyl-L-aspartate-N-lactalocarboxylic acid is preferably 1:(200-800), more preferably 1:(150-250). The polymerization reaction temperature is preferably 10°C-30°C, more preferably 15°C-20°C, and the polymerization reaction time is preferably 48 hours to 96 hours, more preferably 48 hours to 72 hours. The third solution is preferably dichloroacetic acid, and the acidic reagent is preferably a 33% hydrobromic acid-acetic acid solution. The ratio of the block polymer, the third solvent, and the acidic reagent is preferably 1g:10mL:3mL. The reducing agent is preferably dithiothreitol, tris(2-carboxyethyl)phosphine, sodium borohydride, or glutathione.

[0045] This invention provides a method for preparing gold nanoparticles. Specifically, tetrachloroauric acid trihydrate is dissolved in deionized water to obtain a first solution; hexadecyltrimethylammonium bromide is dissolved in deionized water to obtain a second solution; the two solutions are mixed evenly, and pre-cooled sodium borohydride / sodium hydroxide solution is rapidly added to the mixed solution. After stirring for 10 minutes, the mixture is allowed to stand at 27 degrees Celsius for 2 hours to obtain a seed solution. The preferred concentration of the first solution is 0.01 M, the preferred concentration of the second solution is 0.10 M, and the preferred volume ratio of the first solution to the second solution is 1:19.

[0046] Tetrachloroauric acid trihydrate is dissolved in deionized water to obtain a first solution; hexadecyltrimethylammonium bromide is dissolved in deionized water to obtain a second solution; the two solutions are mixed evenly, and silver nitrate solution, hydrochloric acid, and hydroquinone solution are added sequentially, and the mixture is shaken until colorless to obtain the growth solution. The preferred concentrations of the first and second solutions are 0.01 M, 0.1 M, 0.1 M, 1 M, and 0.1 M respectively. The preferred volume ratio of the first, second, silver nitrate, hydrochloric acid, and hydroquinone solutions is 100:1600:8:(1-4):100, and most preferably 100:1600:8:(2-3):100.

[0047] After obtaining the seed solution and growth solution, the seed solution is quickly added to the growth solution and stirred thoroughly. The mixed solution is allowed to stand at 27 degrees Celsius for a period of time, and then purified by centrifugation to obtain a gold nanoparticle solution. The preferred volume ratio of the seed solution to the growth solution is 1:(4.5-6). The preferred standing time is 16-20 hours.

[0048] This invention provides a method for preparing polyamino acid segment-modified gold nanoparticles. Specifically, an amino acid block polymer is dissolved in deionized water, swirled at room temperature to replace the atmosphere with N2, a gold nanoparticle solution is added, and the mixture is incubated in a shaker at 37 degrees Celsius for 72 hours. This invention does not impose any particular limitations on the concentrations of the polyamino acid solution and the gold nanoparticle solution.

[0049] Secondly, this invention provides a method for preparing a gold nanoparticle / cisplatin dual crosslinked hydrogel, specifically as follows: First, the polymer is dissolved in a solvent to obtain a first solution, which is then swirled at room temperature and replaced with an N2 atmosphere. The gold nanoparticle solution is then injected and incubated in a shaker at 37 degrees Celsius for 72 hours. After being left exposed for 24 hours, cisplatin is added, and the mixture is incubated in a shaker at 37 degrees Celsius for 4 days to obtain the gold nanoparticle / cisplatin dual crosslinked hydrogel.

[0050] Thirdly, a third objective of the present invention is to provide the application of the above-mentioned polyamino acid hydrogel as a sustained-release carrier.

[0051] A fourth object of the present invention is to provide a combined drug comprising the above-described polyamino acid hydrogel and other drugs loaded on the polyamino acid hydrogel.

[0052] To further illustrate the present invention, the following detailed description of the amino acid block polymer, gold nanoparticles, gold nanoparticle / cisplatin crosslinked hydrogel and their preparation methods provided by the present invention is provided in conjunction with embodiments.

[0053] Example 1

[0054] 17 mg of cystamine was dissolved in 1 mL of dry dichloromethane to obtain the first solution. 4 g of γ-benzyl-L-glutamate-N-lactalocarboxylic anhydride was placed in a bottle with a side-opening, and 50 mL of dry dichloromethane was added. After the solid was completely dissolved, the first solution was added under a nitrogen atmosphere and stirred thoroughly. The nitrogen atmosphere was replaced, and the ampoule was kept under negative pressure and at 20°C for 66 h of stirring. Then, 500 μL of acetic anhydride was added to seal the solution. After 6 h, the solution precipitated in 800 mL of ice-cold diethyl ether to obtain a white solid. This solid was redissolved in N,N-dimethylformamide, dialyzed against distilled water for 72 h, and then lyophilized to obtain target product 1. 1 g of the target product PBLG-SS-PBLG was dissolved in 10 mL of dichloroacetic acid. After complete dissolution, 3 mL of 33% hydrobromic acid-acetic acid solution was added, and the reaction was carried out at 30°C for 1 h. The solution was precipitated in 300 mL of cold diethyl ether to obtain a white solid, which was redissolved in N,N-dimethylformamide (DMF), dialyzed against distilled water for 48 h, and then dialyzed again for 12 h after the addition of sodium bicarbonate solution (1 M). The solution was then lyophilized to obtain target product 2. 1 g of target product 2 was dissolved in 100 mL of deionized water to obtain a second solution; 46 mg of dithiothreitol was dissolved in 1 mL of deionized water to obtain a third solution. The second and third solutions were thoroughly mixed, and the reaction was carried out under a nitrogen atmosphere for 12 h. After dialyzed against distilled water for 72 h, target product 3 was obtained.

[0055] Analysis of 1H NMR data showed that ( Figure 1 The polymer PLG-SH prepared in Example 1 was successfully obtained, containing a total of 100 glutamic acid units.

[0056] Ellman experiments showed that the disulfide bonds of the glutamic acid block polymer prepared in Example 1 were successfully broken, with a yield of 79%.

[0057] Example 2

[0058] 24 mg of selenocysteine ​​was dissolved in 1 mL of dry dichloromethane to obtain the first solution. 4 g of γ-benzyl-L-glutamate-N-lactalocarboxylic anhydride was placed in a bottle with a side-opening, and 50 mL of dry dichloromethane was added. After the solid was completely dissolved, the first solution was added under a nitrogen atmosphere and stirred thoroughly. The nitrogen atmosphere was replaced, and the mixture was stirred at 20°C for 66 h while maintaining a negative pressure inside the ampoule. Then, 500 μL of acetic anhydride was added to seal the ampoule. After 6 h, the solution precipitated in 800 mL of ice-cold diethyl ether to obtain a white solid. This solid was redissolved in N,N-dimethylformamide, dialyzed against distilled water for 72 h, and then lyophilized to obtain the target product 4. 1 g of the target product PBLG-Se-Se-PBLG was dissolved in 10 mL of dichloroacetic acid. After complete dissolution, 3 mL of 33% hydrobromic acid-acetic acid solution was added, and the reaction was carried out at 30°C for 1 h. The solution was precipitated in 300 mL of cold diethyl ether to obtain a white solid, which was redissolved in DMF, dialyzed against distilled water for 48 h, and then dialyzed again for 12 h after the addition of sodium bicarbonate solution. The solution was then lyophilized to obtain target product 5. 1 g of target product 5 was dissolved in 100 mL of deionized water to obtain a second solution; 100 mg of glutathione was dissolved in 1 mL of deionized water to obtain a third solution. The second and third solutions were thoroughly mixed, and the reaction was carried out under a nitrogen atmosphere for 6 h. After dialyzing against distilled water for 72 h, target product 6 was obtained.

[0059] Analysis of the 1H NMR data showed that the polymer PLG-SeH prepared in Example 2 contained a total of 100 glutamic acid units.

[0060] Example 3

[0061] 9 mg of cystamine was dissolved in 0.5 mL of dry dichloromethane to obtain the first solution. 2 g of β-benzyl-L-aspartate-N-carboxylic anhydride was placed in a bottle with a side-opening, and 30 mL of dry dichloromethane was added. After the solid was completely dissolved, the first solution was added under a nitrogen atmosphere and stirred thoroughly. The nitrogen atmosphere was replaced, and the mixture was stirred at 20°C for 66 h while maintaining a negative pressure inside the ampoule. Then, 500 μL of acetic anhydride was added to seal the solution. After 6 h, the solution precipitated in 500 mL of ice-cold diethyl ether to obtain a white solid. This solid was redissolved in N,N-dimethylformamide, dialyzed against distilled water for 72 h, and then lyophilized to obtain the target product 7. 0.5 g of the target product PBLA-SS-PBLA was dissolved in 5 mL of dichloroacetic acid. After complete dissolution, 1.5 mL of 33% hydrobromic acid-acetic acid solution was added, and the reaction was carried out at 30°C for 1 h. The solution was precipitated in 200 mL of cold diethyl ether to obtain a white solid, which was redissolved in DMF, dialyzed against distilled water for 48 h, and then dialyzed again for 12 h after the addition of sodium bicarbonate solution. The solution was then lyophilized to obtain target product 8. 1 g of target product 8 was dissolved in 100 mL of deionized water to obtain a second solution; 40 mg of dithiothreitol was dissolved in 1 mL of deionized water to obtain a third solution. The second and third solutions were thoroughly mixed, and the reaction was carried out under a nitrogen atmosphere for 12 h. After dialyzed against distilled water for 72 h, target product 9 was obtained.

[0062] Analysis of 1H NMR data showed that the polymer PLA-SH prepared in Example 3 contained a total of 100 aspartic acid units.

[0063] Example 4

[0064] 12 mg of selenocysteine ​​was dissolved in 0.5 mL of dry dichloromethane to obtain the first solution. 2 g of β-benzyl-L-aspartic acid ester-N-lactalic anhydride was placed in a bottle with a side-opening, and 30 mL of dry dichloromethane was added. After the solid was completely dissolved, the first solution was added under a nitrogen atmosphere and stirred thoroughly. The nitrogen atmosphere was replaced, and the mixture was stirred at 20°C for 66 h while maintaining a negative pressure inside the ampoule. Then, 500 μL of acetic anhydride was added to seal the solution. After 6 h, the solution precipitated in 500 mL of ice-cold diethyl ether to obtain a white solid. This solid was redissolved in N,N-dimethylformamide, dialyzed against distilled water for 72 h, and then lyophilized to obtain the target product 10. 0.5 g of the target product PBLA-SS-PBLA was dissolved in 5 mL of dichloroacetic acid. After complete dissolution, 1.5 mL of 33% hydrobromic acid-acetic acid solution was added, and the reaction was carried out at 30°C for 1 h. The solution was precipitated in 200 mL of cold diethyl ether to obtain a white solid, which was redissolved in DMF, dialyzed against distilled water for 48 h, and then dialyzed again for 12 h after the addition of sodium bicarbonate solution. The solution was then lyophilized to obtain target product 11. 1 g of target product 11 was dissolved in 100 mL of deionized water to obtain a second solution; 90 mg of glutathione was dissolved in 1 mL of deionized water to obtain a third solution. The second and third solutions were thoroughly mixed, and the reaction was carried out under a nitrogen atmosphere for 6 h. After dialyzing against distilled water for 72 h, target product 12 was obtained.

[0065] Analysis of the 1H NMR data showed that the polymer PLA-SeH prepared in Example 4 contained a total of 100 aspartic acid units.

[0066] Example 5

[0067] Dissolve 23.7 mg of tetrachloroauric acid trihydrate in 6 mL of deionized water to prepare a tetrachloroauric acid solution. Dissolve 3.3 g of hexadecyltrimethylammonium bromide in 90 mL of deionized water to prepare a CTAB solution. Dissolve 16 mg of sodium hydroxide granules in 40 mL of deionized water to prepare a NaOH solution. Dissolve 15 mg of sodium borohydride in a pre-prepared NaOH solution to prepare a sodium borohydride solution. Dissolve 8.5 mg of silver nitrate in 500 μL of deionized water to prepare a silver nitrate solution. Dilute concentrated sulfuric acid to 1 M to prepare a dilute hydrochloric acid solution. Dissolve 55 mg of hydroquinone in 5 mL of deionized water to prepare a hydroquinone solution.

[0068] Take 9.5 mL of 0.1 M CTAB solution and 0.5 mL of 0.01 M tetrachloroauric acid solution in an Erlenmeyer flask and stir thoroughly. Quickly add 0.6 mL of 0.01 M sodium borohydride solution in sodium hydroxide, stir thoroughly for 10 minutes, and then let stand at 27°C for 2 hours. This serves as the seed solution for gold nanoparticles.

[0069] Take 8.0 mL of 0.1 M CTAB solution and 0.5 mL of 0.01 M tetrachloroauric acid solution in an Erlenmeyer flask and stir thoroughly. Add 40 μL of 0.1 M silver nitrate solution, gently invert, and then add 15 μL of 1 M hydrochloric acid solution. Stir thoroughly, then add 0.5 mL of 0.1 M hydroquinone solution and shake until colorless. Quickly add 2 mL of seed solution, gently invert, and incubate at 27°C for 18 hours. Finally, centrifuge at 16000 g for 10 minutes, remove the supernatant, redisperse with deionized water, and repeat the above steps once to obtain uniformly dispersed gold nanoparticles (Au-CTAB).

[0070] Figure 2 The image shows a transmission electron microscope (TEM) image of the synthesized gold nanoparticles. As can be seen from the image, the synthesized gold nanoparticles possess a uniform and stable rod-like morphology, with an aspect ratio within the range of 8.12 ± 1.6. Meanwhile, Figure 3 The near-infrared II characteristic absorption curve of gold nanoparticles shows that the strongest absorption at 1045nm ensures the high tissue penetration of the light absorption of gold nanoparticles, which is of great significance for the constructed gel in the treatment of solid tumors.

[0071] Example 6

[0072] The glutamic acid block polymer prepared in Example 1 was dissolved in deionized water to prepare a 2% polyamino acid solution. After complete dissolution, the solution was replaced with a nitrogen atmosphere, and an aqueous solution of gold nanoparticles (0.015%) was injected. The solution was incubated in a shaker at 37°C for 72 hours to obtain gold nanoparticles (Au-S-PLG) with surface-modified glutamic acid polymer.

[0073] The lyophilized powders of PLG-SS-PLG, PLG-SH, and Au-S-PLG (1 mg / mL) prepared in Example 1 were analyzed for chemical structural changes by infrared spectroscopy using the potassium bromide tableting method.

[0074] Figure 4 The image shows the infrared spectra of three samples. As can be seen from the image, PLG-SH reaches 2370 cm⁻¹. -1 The appearance of the peak at this point is evidence of successful disulfide bond cleavage. The disappearance of this peak in Au-S-PLG indicates a coordination interaction between the thiol group and the gold nanorod.

[0075] Example 7

[0076] After the Au-S-PLG aqueous solution prepared in Example 6 was left exposed for 24 hours, 1.5% cisplatin was added, and the mixture was incubated in a shaker at 37 degrees Celsius for 4 days to obtain a double crosslinked hydrogel.

[0077] Figure 5The Zeta potential diagrams of Au-CTAB prepared in Example 5, PLG-SH prepared in Example 1, and Au-PLG prepared in Example 6 show that Au-CTAB shows 33.8 mV and Au-SH-PLG shows -55.2 mV, proving that the negatively charged polyglutamic acid chains were successfully modified onto the surface of the gold nanoparticles.

[0078] Figure 6 The image shows the sol-gel transition. As can be seen from the figure, a uniform and stable gel network is obtained after coordination with the dual cross-linking agent.

[0079] Example 8

[0080] 300 μL of the double crosslinked hydrogel (polyglutamic acid concentration of 2%, gold nanoparticle concentration of 0.015%, and cisplatin concentration of 1.5%) prepared in Example 7 was placed on a rotational rheometer, and the gel modulus was determined by time-frequency scanning.

[0081] Figure 7 The time-frequency scan results show that the elastic modulus of the gel remains stable at 313 Pa, which ensures drug delivery while meeting the requirements for injectability.

[0082] Example 9

[0083] 300 μL of the double crosslinked hydrogel prepared in Example 7 (polyglutamic acid concentration of 2%, gold nanoparticle concentration of 0.015%, and cisplatin concentration of 1.5%) was rapidly frozen by liquid nitrogen freezing and its microstructure was then observed by scanning electron microscopy.

[0084] Figure 8 The image shows a scanning electron microscope image of the gel. As can be seen from the image, the gel exhibits a uniform porous structure, which provides the possibility for subsequent drug release.

[0085] Application Example 1

[0086] Using mouse melanoma as the research subject, the drug release behavior of the double cross-linked hydrogel prepared in Example 7 was investigated. Specifically, 50,000 cells / well were seeded in 24-well plates and cultured overnight. After 24 hours, different masses of gel were added to the wells and incubated for 24 hours, respectively set as G1 (0 mg / mL cisplatin, 0 mg / mL gold nanoparticles, no laser irradiation) and G2 (0 mg / mL cisplatin, 0 mg / mL gold nanoparticles, 1.5 W / cm²). 2 Laser irradiation for 10 min), G3 (150 μg / mL cisplatin, 1.54 μg / mL gold nanoparticles, no laser irradiation), G4 (150 μg / mL cisplatin, 1.54 μg / mL gold nanoparticles, 1.5 W / cm²). 2The group was irradiated with laser for 10 min. Simultaneously, equal amounts of cisplatin and gold nanoparticles were added to other groups as free drug groups, designated as G5 (150 μg / mL cisplatin, 1.54 μg / mL gold nanoparticles, no laser irradiation) and G6 (150 μg / mL cisplatin, 1.54 μg / mL gold nanoparticles, 1.5 W / cm²). 2 Laser irradiation for 10 min). Incubate for 24 h and assess the drug toxicity of the gel.

[0087] Figure 9 The results of the MTT assay for the double-crosslinked hydrogel in cells show that, at the same drug dose, the gel group exhibited a significant reduction in the toxicity of both cisplatin and gold nanoparticles. This result is attributed to the sustained-release effect of the gel, which, to a certain extent, can reduce the systemic toxicity caused by high-dose medication while ensuring therapeutic efficacy.

Claims

1. A gold nanoparticle / cisplatin dual-crosslinked polyamino acid hydrogel, characterized in that, It includes cisplatin, gold nanoparticles, amino acid polymers, and solvent, with the following composition ratios by mass percentage: 0.0039%~0.031% gold nanoparticles, 1%~4% cisplatin, 2%~20% amino acid polymers, the remainder being solvent; The structure of the amino acid polymer is shown in formula (I): ； （I） R1 is selected from -CH2- or -(CH2)2-; R2 is selected from -SH or -SeH; x is the degree of polymerization, 50≤x≤800; The gold nanoparticle / cisplatin dual-crosslinked polyamino acid hydrogel was prepared by the following method: An amino acid polymer solution was prepared, fully dissolved at room temperature, and replaced with an N2 atmosphere. A gold nanoparticle solution was added, and the mixture was incubated in a shaker at 37°C. After being left exposed for a period of time, cisplatin was added and incubation continued to obtain the polyamino acid hydrogel.

2. The polyamino acid hydrogel according to claim 1, characterized in that, The mass percentage of the gold nanoparticles is 0.0085% to 0.015%.

3. The polyamino acid hydrogel according to claim 1, characterized in that, The mass percentage of the amino acid polymer is 2% to 8%.

4. The polyamino acid hydrogel according to claim 1, characterized in that, The cisplatin has a mass percentage of 1% to 3%.

5. The polyamino acid hydrogel according to claim 1, characterized in that, The solvent is water or phosphate buffer.

6. The polyamino acid hydrogel according to claim 1, characterized in that, The mass ratio of the amino acid polymer, cisplatin, and gold nanoparticles is (200~500):(100~200):

1.

7. The use of the gold nanoparticle / cisplatin double crosslinked polyamino acid hydrogel according to any one of claims 1-6 in the preparation of sustained-release carriers.

8. A combined drug comprising the polyamino acid hydrogel of any one of claims 1-6, and other drugs loaded on the polyamino acid hydrogel.

Images