Amphiphilic photosensitive polymer as well as preparation method and application thereof

Abstract

The invention provides an amphiphilic photosensitive polymer as well as a preparation method and application thereof. The molecular formula of the amphiphilic polymer is PLGA-b-LRB-b-PEG-SH. The preparation method comprises the following steps: firstly, preparing 2-nitro-1, 3-benzene dichloroacetate, then preparing an amphiphilic photosensitive polymer PLGA-b-LRB-b-PEG-SH through a two-step substitution reaction, applying the polymer to preparation of a nano-micelle drug system, self-assembling the polymer into a nano-micelle with a stable structure in an aqueous solution, modifying a targeted functional group on the nano-micelle, and preparing the nano-micelle drug system. The targeting function is endowed. The prepared nano-micelle drug system has good optical responsiveness, upconversion materials are loaded on the nano-micelle drug system, the optical reaction characteristic is improved, and short-wavelength laser is avoided, so that the diagnosis and treatment effect is efficiently and safely achieved.

Description

Technical Field

[0001] This invention belongs to the field of polymer technology, and particularly relates to an amphiphilic photosensitive polymer, its preparation method, and its application. Background Technology

[0002] Cancer, also known as malignant tumors, has a high incidence and mortality rate, constantly threatening human health. Therefore, accurate, timely, and efficient diagnosis and treatment of cancer are crucial.

[0003] Traditional diagnosis and treatment are independent processes, which presents several drawbacks in cancer clinical treatment: combining medication or surgery in both processes further increases the patient's physical burden. Furthermore, the long interval between diagnosis and treatment often leads to missed opportunities for optimal treatment. Additionally, individual differences and tumor type and size can affect treatment outcomes. Accurate and effective early diagnosis and real-time monitoring of the disease, while minimizing the side effects of diagnosis and treatment, represent an ideal treatment approach. Therapeutic integration is a novel biomedical technology that combines disease monitoring or diagnosis with treatment. Typically, nanotherapeutic agents comprise three key components: imaging agents, therapeutic agents, and nanocarriers. Its advantages include enabling patient triage and personalized medicine, real-time monitoring of the nanomedicine treatment process, and feedback on the nanomedicine treatment's effects.

[0004] Commonly used imaging contrast agents in the medical field include fluorescent contrast agents, magnetic resonance imaging (MRI) contrast agents, X-ray contrast agents, radionuclide contrast agents, and ultrasound contrast agents. Among these, optical signals are easily captured and resolved and offer good controllability, thus optical signal-based diagnostic and imaging technologies are widely used in integrated diagnosis and treatment. Fluorescence is one of the most commonly used optical signals. Researchers have developed various fluorescent contrast agents by adjusting the fluorescence of various fluorescent molecules or nanoparticles, which can be categorized as: organic fluorescent dyes, quantum dots, rare-earth-doped nanoparticles, etc.

[0005] In the medical field, commonly used therapeutic agents include chemotherapy drugs, radiation sources, photosensitizers, photothermal nanoconversion agents, therapeutic genes, and immune checkpoint inhibitors. These have led to the development of novel cancer treatment methods such as photodynamic therapy, photothermal immunotherapy, and intelligent drug delivery systems. However, these treatment methods are currently in the clinical trial and basic research stages, facing various challenges and difficulties.

[0006] Nanotherapeutic agents need to possess both imaging and therapeutic effects, typically achieved by loading imaging and therapeutic agents onto nanocarriers. Most photoresponsive polymers require ultraviolet (UV) light for excitation, but UV light has poor tissue penetration, and prolonged exposure can be harmful to the human body, limiting their application in the biomedical field. Rare-earth upconversion nanoparticles (UCNPs) have a unique energy level structure, capable of absorbing low-energy near-infrared light and emitting higher-energy UV and visible light. UCNPs are also excellent imaging agents. Combining rare-earth upconversion nanoparticles with photoresponsive polymers and loading them with anti-tumor drugs allows for the creation of multifunctional therapeutic agents. When excited with highly tissue-penetrating near-infrared light, the UV light released by the UCNPs can induce photochemical reactions in the photoresponsive polymers, altering their physical or chemical properties, thereby achieving controlled release of anti-tumor drugs. Visible light is used for imaging. Theoretically, this could lead to the construction of multifunctional therapeutic agents. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the purpose of this invention is to provide an amphiphilic photosensitive polymer, its preparation method, and its applications. The specific technical solution is as follows:

[0008] The first aspect of this invention provides an amphiphilic photosensitive polymer, characterized in that its molecular formula is PLGA-b-LRB-b-PEG-SH, and its molecular structure is shown in Formula 1.

[0009]

[0010] In the amphiphilic photosensitive polymer, the molecular formula PLGA-b-LRB-b-PEG-SH, LRB stands for Light Responsive Bone. Specifically, this amphiphilic photosensitive polymer is a photosensitive polylactic acid-glycolic acid-polyethylene glycol block copolymer.

[0011] A second aspect of the present invention provides a method for preparing the above-described amphiphilic photosensitive polymer, comprising the following steps:

[0012] (1) In an alkaline aqueous solution, 1,3-dimethyl-2-nitrobenzene is oxidized by potassium permanganate to give 2-nitro-1,3-phthalic acid; wherein, the molecular structural formula of 1,3-dimethyl-2-nitrobenzene is shown in Formula 2.

[0013]

[0014] The molecular structure of 2-nitro-1,3-phthalic acid is shown in Formula 3.

[0015]

[0016] (2) In solvent A, 2-nitro-1,3-phenylenediamine is reduced by a reducing agent to obtain 2-nitro-1,3-phenylenediamine; wherein, the molecular structure of 2-nitro-1,3-phenylenediamine is shown in Formula 4.

[0017]

[0018] (3) 2-Nitro-1,3-phenylenedimethanol and chloroacetyl chloride are acylated to give 2-nitro-1,3-phenyldichloroacetate; wherein, the molecular structure of 2-nitro-1,3-phenyldichloroacetate is shown in Formula 5.

[0019]

[0020] (4) 2-Nitro-1,3-phenyldichloroacetic acid ester reacts with PLGA in a substitution reaction to give an intermediate product; wherein, the molecular structure of PLGA is shown in Formula 6.

[0021]

[0022] The molecular structure of the intermediate product is shown in Formula 7.

[0023]

[0024] (5) The intermediate product undergoes a substitution reaction with COOH-PEG-SH to obtain the amphiphilic photosensitive polymer; wherein, the molecular structure of COOH-PEG-SH is shown in Formula 8.

[0025]

[0026] Further, step (1) specifically includes: thoroughly mixing 1,3-dimethyl-2-nitrobenzene and an aqueous solution of sodium hydroxide, heating to 80-100°C, adding potassium permanganate in batches, reacting for 48-96 hours, cooling to room temperature, filtering the obtained reaction solution, slowly adding hydrochloric acid solution to the obtained filtrate, adjusting the pH to 2-4, producing a white precipitate, and filtering the solid obtained after filtration, which is 2-nitro-1,3-phthalic acid; wherein the molar ratio of 1,3-dimethyl-2-nitrobenzene and potassium permanganate is 1:2-5, more preferably 1:3-4.

[0027] Preferably, the heating temperature is 90-100°C.

[0028] Preferably, the reaction temperature in step (1) is 80-100℃, more preferably 90-100℃, and the reaction time is 48-96h, more preferably 48-60h.

[0029] Further, step (2) specifically includes: dissolving 2-nitro-1,3-phthalic acid in solvent A, adding boron tetrahydrofuran complex in batches under ice-water bath conditions at 0-4°C, and then raising the reaction system to room temperature to obtain 2-nitro-1,3-benzenedimethanol; wherein solvent A is specifically methanol, ethanol, or a chloroform-acetone mixed solvent; wherein the concentration of boron tetrahydrofuran complex is 0.1-1.0 mol / L; and the molar ratio of boron tetrahydrofuran complex to 2-nitro-1,3-phthalic acid is 3-5:1. Preferably, the reaction time is 6-24 h, more preferably 8-12 h.

[0030] Further, step (3) specifically includes: dissolving 2-nitro-1,3-phenylenediamine in tetrahydrofuran, adding triethylamine, slowly adding chloroacetyl chloride dropwise under an ice-water bath at 0-4℃, then raising the reaction system to room temperature for reaction, after the reaction is completed, filtering to remove triethylamine, rotary evaporating to remove solvent, washing with deionized water, drying with a drying agent, filtration, evaporating solvent for concentration, and column chromatography purification to obtain 2-nitro-1,3-phenylenedichloroacetic acid ester.

[0031] Preferably, the molar ratio of 2-nitro-1,3-benzyldiethanol and chloroacetyl chloride is 1:2-4; and the molar ratio of chloroacetyl chloride and triethylamine is 1:1.

[0032] Preferably, the reaction time is 12-24 hours.

[0033] Preferably, the desiccant is anhydrous magnesium sulfate, anhydrous sodium sulfate, anhydrous calcium chloride, or a molecular sieve;

[0034] Preferably, in the column chromatography purification method, the stationary phase is silica gel, and the eluent is a mixed solvent of n-hexane and ethyl acetate, wherein the volume ratio of n-hexane to ethyl acetate in the mixed solvent is 0.5-3:1, more preferably 1-2:1.

[0035] Further, step (4) specifically includes: dissolving PLGA in solvent B, heating until completely dissolved, adding tetramethylguanidine, and then slowly adding 2-nitro-1,3-phenyldichloroacetic acid ester. After reacting at a certain temperature under a nitrogen atmosphere for a period of time, centrifuging and filtering to remove chloride and tetramethylguanidine, and dialysis purification to obtain the intermediate product.

[0036] Preferably, solvent B is N,N-dimethylformamide, dimethylacetamide, N-methylpyrrolidone, or dimethyl sulfoxide, more preferably N,N-dimethylformamide; the volume-to-molar ratio of solvent B (mL) to PLGA (mol) is 3-6:1; solvent B is anhydrous.

[0037] Preferably, the molar ratio of PLGA to tetramethylguanidine is 1:1.5-2, and the molar ratio of PLGA to 2-nitro-1,3-phenyldichloroacetic acid ester is 1-1.5:2.

[0038] Preferably, the reaction time is 70-120 hours, more preferably 90-100 hours;

[0039] Preferably, the centrifugation and filtration method involves slowly pouring the reaction solution into ice-cold diethyl ether to precipitate the product, with a volume ratio of reaction solution to ice-cold diethyl ether of 1:10. The precipitate is then collected by centrifugation and filtration, washed three times with diethyl ether to remove unreacted chlorides and tetramethylguanidine. The dialysis purification involves dissolving the crude product (after centrifugation and filtration to remove chlorides and tetramethylguanidine) in tetrahydrofuran, placing it in a dialysis bag, dialyzing with deionized water for a period of time, and then lyophilizing to obtain the final product. Preferably, the dialysis time is 40-50 hours.

[0040] Further, step (5) specifically includes: dissolving the intermediate product in N,N-dimethylformamide, heating it to a certain temperature until it is completely dissolved, adding tetramethylguanidine, and then slowly adding COOH-PEG-SH. After reacting for a period of time at a certain temperature under a nitrogen atmosphere, centrifuging and filtering are performed to remove chloride and tetramethylguanidine, and dialysis is used to purify the amphiphilic photosensitive polymer.

[0041] Preferably, the molar ratio of the intermediate product to tetramethylguanidine is 1:1.5-2, and the molar ratio of the intermediate product to COOH-PEG-SH is 1-1.5:3;

[0042] Preferably, the reaction time is 70-120 hours, more preferably 90-100 hours;

[0043] Preferably, the centrifugation and filtration method involves slowly pouring the reaction solution into ice-cold diethyl ether to precipitate the product. The volume ratio of the reaction solution to ice-cold diethyl ether is 1:5-15. The precipitate is collected by centrifugation and filtration, and washed three times with diethyl ether to remove unreacted chlorides and tetramethylguanidine. The dialysis purification step involves dissolving the crude product (after centrifugation and filtration to remove chlorides and tetramethylguanidine) in PBS buffer, placing it in a dialysis bag, dialyzing against deionized water for a period of time, and then lyophilizing to obtain the final product. Preferably, the dialysis time is 60-80 hours.

[0044] A third aspect of the present invention provides an application of the above-described amphiphilic photosensitive polymer in biomedicine.

[0045] A fourth aspect of the present invention provides the application of the above-described amphiphilic photosensitive polymer in the preparation of a photoresponsive nanoparticle drug delivery system. This photoresponsive nanoparticle drug delivery system can load one or more drugs.

[0046] Further, the photoresponsive nanomedicine delivery system is specifically a photosensitive polymer-based upconversion material-loaded photosensitive hybrid nanomicelle system; the preparation method of the photosensitive polymer-based upconversion material-loaded photosensitive hybrid nanomicelle system includes the following steps: dispersing the upconversion material in dimethyl sulfoxide, sonicating for 30-60 min until uniformly dispersed, to obtain an upconversion material dispersion; dissolving the amphiphilic photosensitive polymer as described in claim 1 in dimethyl sulfoxide, mixing it with the upconversion material dispersion, vortexing for 10-30 min, to obtain a mixed solution; then dialyzing the mixed solution with deionized water, freeze-drying to obtain the photosensitive polymer-based upconversion material-loaded photosensitive hybrid nanomicelle system.

[0047] Preferably, the mass ratio (w / w) of the upconversion material to the photosensitive polymer is 1:5-20;

[0048] Preferably, the dialysis time is 48-72 hours, and the drying method is freeze drying.

[0049] The beneficial effects of the present invention are at least as follows:

[0050] This invention discloses an amphiphilic photosensitive polymer, its preparation method, and its applications. Focusing on the amphiphilic photosensitive polymer and its hybrid nanomicelle system loaded with upconversion materials, it overcomes the limitations of traditional photoresponsive drug delivery systems in terms of tissue penetration, spatiotemporal controlled release precision, and biosafety, while also considering drug delivery and in vivo imaging. First, addressing the poor tissue penetration and phototoxicity issues caused by traditional photosensitive materials relying on ultraviolet light excitation, a photoactivated system based on upconversion nanomaterials is designed. Utilizing the deep penetration characteristics of near-infrared light, a cascade response mechanism of "NIR light-UV light-drug release" is employed to achieve remote and precise controlled release from deep lesions, while avoiding damage to healthy tissues from ultraviolet light. Second, a triblock photosensitive polymer, PLGA-b-LRB-b-PEG-SH, is constructed through molecular engineering, integrating multiple functions: it contains an o-nitrophenyl photocleavage group that rapidly breaks down under ultraviolet light triggering, releasing the encapsulated drug; the carrier degrades in vivo into lactic acid and glycolic acid, which are then excreted through metabolism, ensuring the long-term safety of the system. Furthermore, by loading upconversion materials onto micelle cores to form a "photo-drug synergistic" hybrid system, the advantages are: by local irradiation with external NIR light, the upconversion material is activated to emit ultraviolet light, triggering LRB cleavage and releasing the drug, thus enabling on-demand drug delivery to the lesion site; the fluorescence imaging function of the upconversion material can monitor the drug distribution and release process in real time, providing visual guidance for treatment. Attached Figure Description

[0051] One or more embodiments are illustrated by way of example with reference to the accompanying drawings. These illustrations do not constitute a limitation on the embodiments, and unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0052] Figure 1 The photosensitive polymer PLGA-b-LRB-b-PEG-SH in Example 1 of this invention 1 H-NMR spectrum, solvent is d-CDCl3;

[0053] Figure 2 The infrared image of the photosensitive polymer PLGA-b-LRB-b-PEG-SH in Example 1 of this invention;

[0054] Figure 3 This is the GPC diagram of the photosensitive polymer PLGA-b-LRB-b-PEG-SH in Example 1 of the present invention;

[0055] Figure 4 These are the ultraviolet-visible spectra obtained after near-infrared light irradiation for various time periods in Embodiment 2 of the present invention;

[0056] Figure 5 This is a diagram showing the critical micelle concentration of the photosensitive hybrid nanomicelles in Example 3 of the present invention;

[0057] Figure 6 This is a transmission electron microscope image of the nanoparticles prepared in Example 4 of the present invention;

[0058] Figure 7 This is used in Embodiment 4 of the present invention at 1mW / cm 2 The average particle size of the nanomicelles was measured before and after irradiation with 360nm light using dynamic light scattering (DLS).

[0059] Figure 8 This is used in Embodiment 5 of the present invention at 1mW / cm 2 The average particle size of nanomicelles before and after loading upconversion material was measured using dynamic light scattering method under 808nm light irradiation. Detailed Implementation

[0060] To better understand the present invention, it is now further described with reference to the following embodiments and accompanying drawings. The embodiments are for illustrative purposes only and do not limit the invention in any way. In the embodiments, all original reagents and materials are commercially available, and experimental methods not specifically specified are conventional methods and conditions well known in the art, or according to the conditions recommended by the instrument manufacturer.

[0061] Example 1: A method for preparing an amphiphilic photosensitive polymer PLGA-b-LRB-b-PEG-SH, comprising the following steps:

[0062] (1) 1,3-Dimethyl-2-nitrobenzene, sodium hydroxide and water were thoroughly mixed and heated to 100°C. Potassium permanganate was added in batches. After reacting for 48 h, the mixture was cooled to room temperature, filtered, and the filtrate was collected. Hydrochloric acid was added under stirring until the pH reached 4, producing a large amount of white precipitate. The precipitate was then filtered to obtain the white product 2-nitro-1,3-phthalic acid (yield 96%).

[0063]

[0064] (2) 1.0 M BH3·THF solution was slowly added dropwise to 2-nitro-1,3-benzenedicarboxylic acid under ice bath conditions, and the reaction was allowed to proceed for 72 h. Methanol was slowly added, and after the solid was completely dissolved, the solvent was removed, and the solid was redissolved in ethyl acetate. The organic phase was washed three times each with saturated sodium bicarbonate aqueous solution and deionized water, and dried over anhydrous magnesium sulfate. After filtration, solvent evaporation, and concentration, the product was purified by column chromatography. The column chromatography conditions were as follows: the stationary phase was silica gel, and the eluent was a mixture of n-hexane and ethyl acetate, wherein the volume ratio of n-hexane to ethyl acetate in the mixed solvent was 1:1, yielding a white product, 2-nitro-1,3-benzenediol (yield 76%).

[0065]

[0066] (3) Dissolve 2-nitro-1,3-benzenedimethanol in tetrahydrofuran, add triethylamine, and slowly add chloroacetyl chloride dropwise under ice bath conditions. Then raise the reaction system to room temperature and react at room temperature for 12 hours. Remove the triethylamine salt by filtration, remove the solvent by rotary evaporation, wash with water, dry with anhydrous magnesium sulfate, filter, evaporate the solvent to concentrate, and purify the product by column chromatography. The column chromatography purification conditions are: the stationary phase is silica gel, and the eluent is a mixed solvent of n-hexane and ethyl acetate with a volume ratio of n-hexane to ethyl acetate of 1:1. 2-nitro-1,3-benzenedimethylenedichloroacetate (yield 75%) is obtained by distillation.

[0067]

[0068] (4) 2-Nitro-1,3-phenyldichloroacetate was dissolved in N,N-dimethylformamide, tetramethylguanidine was added, and PLGA was slowly added dropwise at 35°C. The reaction was then carried out under a nitrogen atmosphere at 35°C for 96 h. The reaction solution was then slowly poured into ice-cold diethyl ether to precipitate the product, with a volume ratio of reaction solution to ice-cold diethyl ether of 1:10. The precipitate was collected by centrifugation and filtration, and washed three times with diethyl ether to remove unreacted chlorinated derivatives and tetramethylguanidine. The crude product was then dissolved in tetrahydrofuran, placed in a dialysis bag, dialyzed against deionized water for 48 h, and freeze-dried to obtain the intermediate product (yield 73%).

[0069]

[0070] (5) The intermediate product was dissolved in N,N-dimethylformamide (15 mL), and tetramethylguanidine (0.69 g, 6 mmol) was added. COOH-PEG-SH (6.13 g, 3 mmol) was slowly added at 35 °C. The reaction was carried out at 35 °C for 96 h under a nitrogen atmosphere. The reaction solution was then slowly poured into ice-cold diethyl ether to precipitate the product. The volume ratio of the reaction solution to ice-cold diethyl ether was 1:15. The precipitate was collected by centrifugation and filtration, and washed three times with diethyl ether to remove unreacted chlorinated compounds and tetramethylguanidine. The crude product was then dissolved in PBS buffer, placed in a dialysis bag, dialyzed against deionized water for 72 h, and freeze-dried to obtain PLGA-b-LRB-b-PEG-SH (yield 68%).

[0071]

[0072] The NMR results of the above compounds are as follows Figure 1 As shown, the infrared data is as follows Figure 2 As shown, GPC data is as follows Figure 3 As shown, the clear characteristic peaks from NMR and IR data confirm the successful synthesis of the product. Furthermore, the accurate molecular weight of the polymer can be determined using GPC data.

[0073] Example 2: Investigating the photoresponse behavior of the amphiphilic photosensitive polymer PLGA-b-LRB-b-PEG-SH

[0074] (1) The photosensitive polymer PLGA-b-LRB-b-PEG-SH was dissolved in dimethyl sulfoxide.

[0075] (2) One group was left untreated, while the other group was irradiated with near-infrared light for a certain period of time, and then the solution was detected by ultraviolet-visible spectroscopy.

[0076] (3) No spectral changes in the solution could be detected even after 24 hours without any near-infrared light irradiation.

[0077] (4) After near-infrared irradiation, an absorption band corresponding to photochromic nitrosobenzaldehyde was detected in the 300-350 nm region. The increase in absorbance over time indicates an increase in the number of small molecules involved in the cleavage, such as... Figure 4 As shown.

[0078] Example 3: Critical micelle concentration (CMC) of the amphiphilic photosensitive polymer PLGA-b-LRB-b-PEG-SH

[0079] The critical micelle concentration of the amphiphilic photosensitive polymer PLGA-b-LRB-b-PEG-SH prepared in Example 1 was determined using the fluorescent probe method.

[0080] (1) Preparation of pyrene solution: Dissolve pyrene in acetone to prepare a solution with a concentration of 12 × 10⁻⁶. -5 M's pyrene solution;

[0081] (2) Preparation of sample solution: Weigh 1-5 mg of PLGA-b-LRB-b-PEG-SH and dissolve it in 10-100 mL of acetone. Quickly add the solution to 50-300 mL of deionized water and stir for 24-48 h to evaporate the acetone, obtaining a polymer mother liquor with a concentration of 0.1 mg / mL. Dilute to a series of concentrations (concentration range: 0.0001-0.1 mg / mL). Take 20 10 mL volumetric flasks, add 0.1 mL of the pyrene solution prepared in step (1) to each flask, and then add the copolymer solutions of different concentrations to make up to volume. Shake well to obtain the sample solution. The concentration of pyrene in the sample solution is 12 × 10⁻⁶. -7 M;

[0082] (3) Fluorescence spectroscopy test: The fluorescence excitation spectrum of the sample solution was scanned at 300-350 nm with an emission wavelength of 373 nm. The intensity ratio (Ig) at wavelengths of 337 nm and 335 nm was taken. 337 / I 335 Plotting the logarithm of the polymer concentration, the x-axis corresponding to the abrupt change point of the curve is lg(CMC). The critical micelle concentration of PLGA-b-LRB-b-PEG-SH prepared in Example 1 was measured to be 3.14 μg / mL. Figure 5 As shown.

[0083] Example 4: Preparation of a photosensitive polymer-supported upconversion material photosensitive hybrid nanomicelle system

[0084] (1) Disperse the upconversion material in the solvent dimethyl sulfoxide and sonicate it to make it uniformly dispersed;

[0085] (2) Dissolve the photosensitive polymer PLGA-b-LRB-b-PEG-SH in dimethyl sulfoxide and vortex.

[0086] (3) The mixed solution was added to a dialysis bag, dialyzed with deionized water for a period of time, and then freeze-dried to prepare photosensitive polymer micelles.

[0087] Preferably, the dialysis time is 48 hours, and the drying method is freeze drying.

[0088] The prepared nanoparticles were characterized using transmission electron microscopy, confirming that the nanoparticles were successfully prepared. Figure 6 As shown.

[0089] At 1mW / cm 2Under 360nm light irradiation, the average particle size of the nanomicelles before and after loading with the upconversion material was tested using dynamic light scattering. The final measured particle size increased from 160.8nm to 234.7nm, demonstrating that the micelles possess excellent optical properties, such as... Figure 7 As shown.

[0090] Example 5: Preparation of a photosensitive polymer-supported upconversion material photosensitive hybrid nanomicelle system

[0091] (1) Disperse the upconversion material in the solvent dimethyl sulfoxide and sonicate it to make it uniformly dispersed;

[0092] (2) Dissolve the photosensitive polymer PLGA-b-LRB-b-PEG-SH in dimethyl sulfoxide and vortex.

[0093] (3) The mixed solution was added to a dialysis bag, dialyzed with deionized water for a period of time, and then freeze-dried to prepare photosensitive polymer micelles.

[0094] Preferably, the mass ratio (m / m) of the upconversion material to the photosensitive polymer is 1:10;

[0095] Preferably, the dialysis time is 48 hours, and the drying method is freeze drying.

[0096] The prepared nanoparticles were characterized by transmission electron microscopy, which proved that the nanoparticles were successfully prepared.

[0097] At 1mW / cm 2 Under 808 nm light irradiation, the average particle size of the nanomicelles before and after loading with the upconversion material was measured using dynamic light scattering. The final measured particle size increased from 132.30 nm to 439.30 nm, demonstrating that the micelles possess excellent optical properties, such as... Figure 8 As shown.

Claims

1. An amphiphilic photosensitive polymer, characterized in that, Its molecular formula is PLGA-b-LRB-b-PEG-SH, and its molecular structure is shown in Formula 1.

2. A method for preparing the amphiphilic photosensitive polymer according to claim 1, characterized in that, Includes the following steps: (1) In an alkaline aqueous solution, 1,3-dimethyl-2-nitrobenzene is oxidized by potassium permanganate to give 2-nitro-1,3-phthalic acid; wherein, the molecular structural formula of 1,3-dimethyl-2-nitrobenzene is shown in Formula 2. The molecular structure of 2-nitro-1,3-phthalic acid is shown in Formula 3. (2) In solvent A, 2-nitro-1,3-phenylenediamine is reduced by a reducing agent to obtain 2-nitro-1,3-phenylenediamine; wherein, the molecular structure of 2-nitro-1,3-phenylenediamine is shown in Formula 4. (3) 2-Nitro-1,3-phenylenedimethanol and chloroacetyl chloride are acylated to give 2-nitro-1,3-phenyldichloroacetate; wherein, the molecular structure of 2-nitro-1,3-phenyldichloroacetate is shown in Formula 5. (4) 2-Nitro-1,3-phenyldichloroacetic acid ester reacts with PLGA in a substitution reaction to give an intermediate product; wherein, the molecular structure of PLGA is shown in Formula 6. The molecular structure of the intermediate product is shown in Formula 7. (5) The intermediate product undergoes a substitution reaction with COOH-PEG-SH to obtain the amphiphilic photosensitive polymer; wherein, the molecular structure of COOH-PEG-SH is shown in Formula 8.

3. The method for preparing the amphiphilic photosensitive polymer according to claim 2, characterized in that, Step (1) specifically includes: thoroughly mixing 1,3-dimethyl-2-nitrobenzene and sodium hydroxide aqueous solution, heating to 80-100℃ and adding potassium permanganate in batches, reacting for 48-96h and then cooling to room temperature, filtering the obtained reaction solution, slowly adding hydrochloric acid solution to the obtained filtrate, adjusting the pH to 2-4, producing a white precipitate, and the solid obtained after filtration is 2-nitro-1,3-phthalic acid; The molar ratio of 1,3-dimethyl-2-nitrobenzene to potassium permanganate is 1:2-5.

4. The method for preparing the amphiphilic photosensitive polymer according to claim 2, characterized in that, Step (2) specifically includes: dissolving 2-nitro-1,3-benzenedicarboxylic acid in solvent A, adding borane tetrahydrofuran complex in batches under ice-water bath conditions of 0-4℃, and then raising the reaction system to room temperature to obtain 2-nitro-1,3-benzenediol; Solvent A is specifically methanol, ethanol, or a chloroform-acetone mixture. The concentration of the boranetetrahydrofuran complex is 0.1-1.0 mol / L; the molar ratio of the boranetetrahydrofuran complex to 2-nitro-1,3-phthalic acid is 3-5:1; and the reaction time is 6-24 h.

5. The method for preparing the amphiphilic photosensitive polymer according to claim 2, characterized in that, Step (3) specifically includes: dissolving 2-nitro-1,3-phenylenediamine in tetrahydrofuran solution, adding triethylamine, slowly adding chloroacetyl chloride dropwise under an ice-water bath at 0-4℃, then raising the reaction system to room temperature for reaction, after the reaction is completed, filtering to remove triethylamine, rotary evaporating to remove solvent, washing with deionized water, drying with a drying agent, filtration, evaporating solvent and concentrating to obtain 2-nitro-1,3-phenylenedichloroacetic acid ester; The molar ratio of 2-nitro-1,3-benzyldiethanol and chloroacetyl chloride is 1:2-4; the molar ratio of chloroacetyl chloride and triethylamine is 1:1; and the reaction time is 12-24 h.

6. The method for preparing the amphiphilic photosensitive polymer according to claim 2, characterized in that, Step (4) specifically includes: dissolving PLGA in solvent B, heating until completely dissolved, adding tetramethylguanidine, and then slowly adding 2-nitro-1,3-phenyldichloroacetic acid ester. After reacting under a nitrogen atmosphere, centrifuging and filtering are used to remove chloride and tetramethylguanidine, and dialysis is used to purify the intermediate product. The solvent B is N,N-dimethylformamide, dimethylacetamide, N-methylpyrrolidone, or dimethyl sulfoxide; the molar ratio of PLGA to tetramethylguanidine is 1:1.5-2, and the molar ratio of PLGA to 2-nitro-1,3-phenyldichloroacetate is 1-1.5:2; the reaction time is 70-120 h; the centrifugation and filtration method involves slowly pouring the reaction solution into ice-cold diethyl ether to precipitate the product, with a volume ratio of reaction solution to ice-cold diethyl ether of 1:10, centrifuging and filtering to collect the precipitate, washing it three times with diethyl ether to remove unreacted chlorides and tetramethylguanidine; the dialysis purification involves dissolving the crude product, after centrifugation and filtration to remove chlorides and tetramethylguanidine, in tetrahydrofuran, dialyzing with deionized water, and then lyophilizing to obtain the intermediate product.

7. The method for preparing the amphiphilic photosensitive polymer according to claim 2, characterized in that, Step (5) specifically includes: dissolving the intermediate product in N,N-dimethylformamide, heating until completely dissolved, adding tetramethylguanidine, then adding COOH-PEG-SH, reacting under a nitrogen atmosphere, centrifuging and filtering to remove chloride and tetramethylguanidine, and dialysis purification to obtain the amphiphilic photosensitive polymer; The molar ratio of the intermediate product to tetramethylguanidine is 1:1.5-2, and the molar ratio of the intermediate product to COOH-PEG-SH is 1-1.5:3; the reaction time is 70-120 h; the centrifugation and filtration method involves slowly pouring the reaction solution into ice-cold ether to precipitate the product, with a volume ratio of reaction solution to ice-cold ether of 1:5-15, centrifuging and filtering to collect the precipitate, washing with ether 3-5 times to remove unreacted chlorides and tetramethylguanidine; the dialysis purification involves dissolving the crude product, after centrifugation and filtration to remove chlorides and tetramethylguanidine, in PBS buffer, dialyzing with deionized water, and then lyophilizing to obtain the amphiphilic photosensitive polymer.

8. The application of the amphiphilic photosensitive polymer according to claim 1 in biomedicine.

9. The application of the amphiphilic photosensitive polymer according to claim 1 in the preparation of a photoresponsive nanoparticle drug delivery system.

10. The application according to claim 9, characterized in that, The photoresponsive nanomedicine delivery system is specifically a photosensitive polymer-based upconversion material-loaded photosensitive hybrid nanomicelle system; the preparation method of the photosensitive polymer-based upconversion material-loaded photosensitive hybrid nanomicelle system includes the following steps: The upconversion material is dispersed in dimethyl sulfoxide and sonicated for 30-60 min until uniformly dispersed to obtain an upconversion material dispersion. The amphiphilic photosensitive polymer as described in claim 1 is dissolved in dimethyl sulfoxide and mixed with the upconversion material dispersion. The mixture is vortexed for 10-30 min to obtain a mixed solution. The mixed solution is then dialyzed with deionized water and freeze-dried to obtain the photosensitive polymer-based upconversion material-loaded photosensitive hybrid nanomicelle system.

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