A conjugated polymer, nanoparticles and preparation method and application thereof

Abstract

The application discloses a kind of conjugated polymers, including B-H or B-NO2, and prepare its nanoparticle by nanoscale coprecipitation method, the conjugated polymer synthesis step is easy, structure is easy to modify and good repeatability;The conjugated polymer nanoparticle has better photodynamic performance under the excitation of near infrared light, has photodynamic property under 730nm laser irradiation in aqueous solution, can produce 1 O2, ·OH and O2 ‑ ·, nitro group can be introduced into polymer, which can significantly enhance its photodynamic performance.The water-soluble nanoparticles can be used for photodynamic therapy of tumor under excitation light irradiation, realize the diagnosis and treatment integration of single wavelength irradiation, and have potential application prospect in biomedical field.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of biological optical diagnosis and treatment, and more particularly relates to a conjugated polymer, a nanoparticle and a preparation method and application thereof. BACKGROUND

[0002] Surgical resection of solid tumors is still the preferred treatment for cancer treatment. Although the medical technology of various countries is developing rapidly, it is still a challenging thing to completely treat cancer. Therefore, people have been committed to finding new imaging methods and cancer treatment methods. In recent years, the emerging non-invasive imaging method of fluorescence imaging has begun to attract attention. In addition, phototherapy including photodynamic and photothermal therapy has also been valued by people.

[0003] Phototherapy, including photodynamic therapy and photothermal therapy, is a light-induced, effective and non-invasive cancer treatment method. Compared with traditional treatment methods, it can selectively act on tumor sites, reduce drug toxicity and improve treatment effect. Under laser irradiation, molecular oxygen is sensitized to produce a series of reactive oxygen species, inducing apoptosis and death of cancer cells. Although phototherapy can be used as a strategy for early tumor treatment and an auxiliary means for surgical treatment of advanced tumors, there are still some problems in clinical aspects. For example, the solubility of photosensitizers in a physical environment is very poor and has a tendency to aggregate. At the same time, the currently reported photosensitizers still have unreasonable effects, and the photodynamic performance needs to be improved. In addition, the traditional type II photosensitizer produces singlet oxygen O2 through triplet energy transfer, but this kind of photosensitizer has strong oxygen dependence, which seriously affects the efficacy of photodynamic therapy in the hypoxic microenvironment of tumors, and rapid oxygen supply depletion during treatment further aggravates hypoxia. In contrast, type I photosensitizers can efficiently generate reactive oxygen species such as superoxide anion free radicals (O2·) and hydroxyl free radicals (·OH) through electron transfer or proton transfer under severe hypoxic conditions, effectively killing cancer cells. However, to date, only a few type I photosensitizers have been reported, and there are still some challenges in the design and development of type I photosensitizers. 1 O2, but this kind of photosensitizer has strong oxygen dependence, which seriously affects the efficacy of photodynamic therapy in the hypoxic microenvironment of tumors, and rapid oxygen supply depletion during treatment further aggravates hypoxia. In contrast, type I photosensitizers can efficiently generate reactive oxygen species such as superoxide anion free radicals (O2·) and hydroxyl free radicals (·OH) through electron transfer or proton transfer under severe hypoxic conditions, effectively killing cancer cells. However, to date, only a few type I photosensitizers have been reported, and there are still some challenges in the design and development of type I photosensitizers. - ·) and hydroxyl free radicals (·OH), effectively killing cancer cells. However, to date, only a few type I photosensitizers have been reported, and there are still some challenges in the design and development of type I photosensitizers. SUMMARY

[0004] The purpose of the present application is to overcome the above shortcomings, provide a conjugated polymer, a nanoparticle and a preparation method thereof, and the conjugated polymer nanoparticle exhibits good photodynamic performance and can be used for photodynamic therapy under light irradiation, and has potential application prospects in the field of biomedicine.

[0005] To achieve the above-mentioned purpose, the present application is realized by the following technical scheme:

[0006] A conjugated polymer, the conjugated polymer is B-H or B-NO2, and the structural formula of the conjugated polymer is as follows:

[0007]

[0008] wherein R 1 group is H and NO2, R 2 group is a linear or branched alkyl group of 1-12 carbon atoms.

[0009] The preparation method of the conjugated polymer comprises the following steps:

[0010] 2,6-bis(trimethyltin)-4,4-bis(2-ethylhexyl)-dithienocyclopentadiene, 4,7-bis(2-bromo-5-thienyl)-2,1,3-benzothiadiazole and a palladium catalyst are mixed, an organic solvent is added under nitrogen protection, and a conjugated polymer B-H is prepared by reaction; the synthesis route is as follows:

[0011]

[0012] 2,6-bis(trimethyltin)-4,4-bis(2-ethylhexyl)-dithienocyclopentadiene, 4,7-bis(5-bromothiophene-2-yl)-5,6-dinitro-2,1,3-benzothiadiazole and a palladium catalyst are mixed under nitrogen protection, an organic solvent is added under nitrogen protection, and a conjugated polymer B-NO2 is prepared by reaction; the synthesis route is as follows:

[0013]

[0014] Preferably, the molar ratio of the 2,6-bis(trimethyltin)-4,4-bis(2-ethylhexyl)-dithienocyclopentadiene, 4,7-bis(2-bromo-5-thienyl)-2,1,3-benzothiadiazole and the palladium catalyst is (1:0.1) to (1:0.5), preferably 1:0.1;

[0015] The molar ratio of the 2,6-bis(trimethyltin)-4,4-bis(2-ethylhexyl)-dithienocyclopentadiene, 4,7-bis(5-bromothiophene-2-yl)-5,6-dinitro-2,1,3-benzothiadiazole and the palladium catalyst is (1:0.1) to (1:0.5), preferably 1:0.1.

[0016] The application further provides a conjugated polymer nanoparticle, which is a conjugated polymer nanoparticle prepared by using an amphiphilic polymer F127 and a nanoscale co-precipitation method based on the conjugated polymer.

[0017] The conjugated polymer nanoparticles include BH nanoparticles or B-NO2 nanoparticles. The BH nanoparticles have a primary absorption peak at 614 nm and a primary emission peak at 936 nm; the B-NO2 nanoparticles have a primary absorption peak at 684 nm and a primary emission peak at 1060 nm. Compared to BH nanoparticles, B-NO2 nanoparticles with nitro groups exhibit a significant red-shift in absorption and emission wavelengths, with absorption wavelengths shifted by 70 nm and emission wavelengths shifted by 124 nm. This red-shifted emission wavelength is beneficial for improving imaging depth and clarity.

[0018] The conjugated polymer nanoparticles, when excited by a 730nm light source in an organic solvent or aqueous solution, emit light in the second near-infrared region of 1000-1700nm.

[0019] The above conjugated polymer nanoparticles have photodynamic properties under 730nm laser irradiation in aqueous solution and can produce 1 O2, ·OH and O2 - The introduction of nitro groups into polymers can significantly enhance their photodynamic properties.

[0020] The present invention also provides a method for preparing the conjugated polymer nanoparticles, comprising the following steps:

[0021] dissolving the conjugated polymer according to claim 1 in THF to obtain a THF solution of the conjugated polymer;

[0022] dissolving the amphiphilic polymer F127 in deionized water to obtain an F127 aqueous solution;

[0023] Add the THF solution of the conjugated polymer to the F127 aqueous solution;

[0024] After ultrasonic vibration, THF is removed to obtain an aqueous solution of conjugated polymer nanoparticles.

[0025] The present invention also provides the use of the conjugated polymer in preparing a photodynamic therapy agent for tumors under excitation light irradiation, which refers to using the conjugated polymer nanoparticles to prepare a photodynamic therapy agent for tumors under excitation light irradiation, and can eliminate tumor cells assisted by 730nm laser irradiation.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The present invention designs a conjugated polymer and prepares its nanoparticles. The conjugated polymer molecules have simple synthesis steps, easy structural modification and good repeatability. The conjugated polymer nanoparticles have good photodynamic properties under the excitation of near-infrared light. The water-soluble nanoparticles can be used for photodynamic therapy of tumors under excitation light, realizing the integration of diagnosis and treatment with single-wavelength irradiation. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is the hydrogen spectrum of the conjugated polymer BH described in Example 1 of the present invention;

[0029] Figure 2 This is the hydrogen spectrum of the conjugated polymer B-NO2 described in Example 2 of the present invention;

[0030] Figure 3 This is the DLS spectrum of the BH nanoparticles described in Example 3 of the present invention;

[0031] Figure 4 TEM image of the BH nanoparticles described in Example 3 of the present invention;

[0032] Figure 5 This is the DLS spectrum of the B-NO2 nanoparticles described in Example 4 of the present invention;

[0033] Figure 6 TEM image of the B-NO2 nanoparticles described in Example 4 of the present invention;

[0034] Figure 7 The absorption spectra of BH nanoparticles and B-NO2 nanoparticles described in the embodiments of the present invention;

[0035] Figure 8 The emission spectra of BH nanoparticles and B-NO2 nanoparticles described in the embodiments of the present invention;

[0036] Figure 9 414nm absorption peak intensity of the BH nanoparticles and B-NO2 nanoparticles described in the embodiment of the present invention under 730nm laser irradiation versus time;

[0037] Figure 10 The B-NO2 nanoparticles described in the embodiment of the present invention are produced 1 O2 detection chart;

[0038] Figure 11 This is a graph showing the generation of OH by B-NO2 nanoparticles according to an embodiment of the present invention;

[0039] Figure 12 The B-NO2 nanoparticles described in the embodiment of the present invention generate O2 - Detection diagram. DETAILED DESCRIPTION

[0040] The preferred embodiments of the present invention will be described in more detail below with reference to the accompanying drawings and specific examples.

[0041] Example 1

[0042] The present embodiment provides a conjugated polymer B-H having the following structure:

[0043]

[0044] The synthesis route of the conjugated polymer B-H is as follows:

[0045]

[0046] The preparation method of the conjugated polymer B-H includes the following steps:

[0047] 2,6-bis(trimethyltin)-4,4-bis(2-ethylhexyl)-dithieno cyclopentadiene (100 mg, 0.137 mmol (referred to as compound 1), 4,7-bis(2-bromo-5-thiophenyl)-2,1,3-benzothiadiazole (62.8 mg, 0.137 mmol) (referred to as compound 2), and tetrakis(triphenylphosphine)palladium (16.2 mg, 0.014 mmol) are weighed into a reaction bottle, then toluene (100 mL) is added under nitrogen protection, and then the reaction is stirred at 100°C for 24 h. After the reaction is completed, the reaction solution is dropped into 150 mL of methanol for sedimentation, followed by filtration, washing, and drying to obtain black solid powder B-H (61.9 mg, 62.1%). Its hydrogen spectrum is as shown in Figure 1

[0048] Embodiment 2

[0049] The present embodiment provides a conjugated polymer B-NO2 having the following structure:

[0050]

[0051] The synthesis route of the conjugated polymer B-NO2 is as follows:

[0052]

[0053] The preparation method of the conjugated polymer B-NO2 includes the following steps:

[0054] ​Compound 1 (100 mg, 0.137 mmol), 4,7-bis(5-bromothiophen-2-yl)-5,6-dinitro- 2,1,3-benzothiadiazole (75.1 mg, 0.137 mmol) (abbreviation: compound 3), tetrakis(triphenylphosphine)palladium (16.2 mg, 0.014 mmol) were weighed into a reaction flask, then toluene (100 mL) was added under nitrogen protection, and then the reaction was stirred at 100°C for 24 h. After the reaction was completed, the reaction solution was dropped into 150 mL of methanol for sedimentation, followed by filtration, washing, and drying to obtain black solid powder B-NO2 (73.2 mg, 65.2%). Its hydrogen spectrum is shown in Figure 2

[0055] Example 3

[0056] This example provides B-H nanoparticles based on the conjugated polymer B-H described in Example 1, and the preparation method comprises the following steps:

[0057] First, the polymer B-H (1 mg) was dissolved in THF (2 mL), and then the solution was quickly added to deionized water (20 mL) containing the amphiphilic substance Pluronic F127 (20 mg) and shaken in an ultrasonic cell crusher for 5 min. After ultrasonic treatment, the solution was blown with nitrogen under magnetic stirring for 2 h to remove THF. After the removal of THF, the impurities were removed by filtration with a water-based filter head and centrifuged at a speed of 3000 r / min for 20 min. The solution at the bottom of the ultrafiltration centrifuge tube was poured out, and deionized water was added to the sample slot on the centrifuge tube for washing. After three times of back-and-forth operation of the centrifugation step, a quantitative B-HNPs aqueous solution was obtained.

[0058] Figure 3 and Figure 4 The DLS spectrum and TEM image of B-H nanoparticles are shown in the figure. First, the B-HNPs were characterized by transmission electron microscopy (TEM), and it was determined that the particle size of the B-H nanoparticles was about 145 nm, uniformly distributed in spherical morphology, which was consistent with the characterization results of the laser particle size analyzer (DLS).

[0059] Example 4

[0060] This example provides B-NO2 nanoparticles based on the conjugated polymer B-NO2 described in Example 2, and the preparation method comprises the following steps:

[0061] ​First, polymer B-NO2 (1 mg) was dissolved in THF (2 mL), and then the solution was quickly added to deionized water (20 mL) containing amphiphilic material Pluronic F127 (20 mg) in an ultrasonic cell crusher and shaken for 5 min. After ultrasonic treatment, the solution was blown with nitrogen for 2 h under magnetic stirring to remove THF. After the removal of THF, the impurities were removed by filtration with a water-based filter head and centrifugation. After centrifugation at 3000 r / min for 20 min, the solution at the bottom of the ultrafiltration centrifuge tube was poured out, and deionized water was added to the sample slot on the centrifuge tube for washing. After the steps of centrifugation were repeated three times, a quantitative B-NO2 NPs aqueous solution was obtained.

[0062] Figure 5 and Figure 6 The DLS spectrum and TEM image of B-NO2 nanoparticles are shown in FIG. 1. First, the B-NO2 NPs were characterized by transmission electron microscopy (TEM), and it was determined that the particle size of the B-NO2 nanoparticles was about 135 nm, which was uniformly distributed in a spherical shape, which was consistent with the characterization results of the laser particle size analyzer (DLS).

[0063] Figure 7 and Figure 8 The absorption and emission spectra of the B-H nanoparticles and B-NO2 nanoparticles prepared in the embodiments of the present application are shown in FIG. 2. The main absorption peak of the B-H nanoparticles is at 614 nm, and the main emission peak is at 936 nm; the main absorption peak of the B-NO2 nanoparticles is at 684 nm, and the main emission peak is at 1060 nm. Compared with the B-H nanoparticles, the B-NO2 nanoparticles with a nitro group exhibit a significant absorption / emission red shift, with an absorption red shift of 70 nm and an emission red shift of 124 nm. The more red-shifted emission wavelength is conducive to improving the depth and clarity of imaging.

[0064] The ability of the B-H nanoparticles and B-NO2 nanoparticles to generate photodynamic power can be compared by the following method:

[0065] 1,3-Diphenyl isobenzofuran (DPBF) was used to test the photodynamic properties of the two nanoparticles. Under 730 nm (1 W / cm 2 ) laser irradiation, the nanoparticles generated ROS, and the absorption of DPBF at 414 nm gradually decreased. By comparing the decline slope of the absorption peak of DPBF at 414 nm, the strength of the ROS generation ability of the two nanoparticles was further judged. Figure 9 is the absorption spectrum of DPBF under 730 nm (1 W / cm 2) Under laser irradiation, the 414nm absorption peak intensity of the BH nanoparticles and B-NO2 nanoparticles prepared in the embodiment of the present invention changes with time. It can be found from the figure that laser irradiation of B-NO2 nanoparticles can generate more ROS, indicating that the introduction of nitro groups in the polymer can improve its photodynamic performance.

[0066] Figure 10 The B-NO2 nanoparticles prepared in Example 4 of the present invention generate 1 O2 detection diagram. Using singlet oxygen probe (SOSG) to detect 1 O2 generation, at 730nm (1W / cm 2 ) laser irradiation, the fluorescence intensity of SOSG at 525nm gradually increased, indicating that laser irradiation can produce 1 O2.

[0067] Figure 11 This is a graph showing the generation of ·OH by B-NO2 nanoparticles prepared in Example 4 of the present invention. Aminophenylfluorescein (APF) was used to detect the generation of ·OH at 730 nm (1 W / cm 2 ) laser irradiation, the fluorescence intensity of APF at 510 nm gradually increased, indicating that ·OH can be produced under laser irradiation.

[0068] Figure 12 The B-NO2 nanoparticles prepared in Example 4 of the present invention generate O2 - Detection diagram. Use dihydroethidium (DHE) to detect O2 - ·The generation of 2 ) Under laser irradiation, the fluorescence intensity of DHE at 625nm gradually increased, indicating that O2 can be produced under laser irradiation. - ·.

[0069] While various embodiments of the present invention have been described above, the foregoing description is intended to be illustrative and non-exhaustive, and is not intended to be limiting of the disclosed embodiments. Numerous modifications and variations will be apparent to those skilled in the art without departing from the scope and technical principles of the described embodiments, and such modifications and variations should be considered within the scope of the present invention.

Claims

1. A conjugated polymer for use in the preparation of a photodynamic therapy agent for tumors under excitation light irradiation, characterized in that, The conjugated polymer is B-NO2, and the structural formula of the conjugated polymer is as follows: ； wherein R 1 group is NO2, R 2 group is a straight or branched chain alkyl group of 1 to 12 carbon atoms.

2. A method of preparing the conjugated polymer of claim 1, characterized by, The method comprises the following steps: The conjugated polymer B-H is prepared by mixing 2,6-bis(trimethyltin)-4,4-bis(2-ethylhexyl)-dithieno cyclopentadiene, 4,7-bis(2-bromo-5-thiophenyl)-2,1,3-benzothiadiazole and a palladium catalyst, adding an organic solvent under nitrogen protection and reacting. The conjugated polymer B-NO2 is prepared by mixing 2,6-bis(trimethyltin)-4,4-bis(2-ethylhexyl)-dithieno cyclopentadiene, 4,7-bis(5-bromothiophene-2-yl)-5,6-dinitro-2,1,3-benzothiadiazole and a palladium catalyst, adding an organic solvent under nitrogen protection and reacting.

3. The method for preparing a conjugated polymer according to claim 2, wherein The molar ratio of the 2,6-bis(trimethyltin)-4,4-bis(2-ethylhexyl)-dithieno cyclopentadiene, 4,7-bis(2-bromo-5-thiophenyl)-2,1,3-benzothiadiazole and the palladium catalyst is 1:1:0.

1. The molar ratio of the 2,6-bis(trimethyltin)-4,4-bis(2-ethylhexyl)-dithieno cyclopentadiene, 4,7-bis(5-bromothiophene-2-yl)-5,6-dinitro-2,1,3-benzothiadiazole and the palladium catalyst is 1:1:0.

1.

4. A conjugated polymer nanoparticle, characterized in that, The conjugated polymer nanoparticles are prepared by using the amphiphilic polymer F127 and a nano co-precipitation method based on the conjugated polymer of claim 1.

5. The conjugated polymer nanoparticle of claim 4, wherein, The conjugated polymer nanoparticles comprise B-H nanoparticles or B-NO2 nanoparticles, the B-H nanoparticles have a main absorption peak at 614 nm and a main emission peak at 936 nm, and the B-NO2 nanoparticles have a main absorption peak at 684 nm and a main emission peak at 1060 nm.

6. The conjugated polymer nanoparticle of claim 4, wherein, The conjugated polymer nanoparticles emit light in the near-infrared second region of 1000-1700 nm under excitation of a 730 nm light source in an organic solvent or an aqueous solution.

7. The conjugated polymer nanoparticle of claim 4, wherein, The conjugated polymer nanoparticles have photodynamic properties in aqueous solution under 730 nm laser irradiation, and can produce 1 O2, ·OH and O2 - ·.

8. A method for preparing the conjugated polymer nanoparticle according to any one of claims 4 to 6, characterized by, The method comprises the following steps: The conjugated polymer of claim 1 is dissolved in THF to obtain a THF solution of the conjugated polymer; The amphiphilic polymer F127 is dissolved in deionized water to obtain an F127 aqueous solution; The THF solution of the conjugated polymer is added to the F127 aqueous solution; After ultrasonic oscillation, the THF is removed to obtain an aqueous solution of the conjugated polymer nanoparticles.

9. Use of the conjugated polymer of claim 1 in the preparation of a photodynamic therapy reagent for tumor irradiation under excitation light.

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