Polymer photosensitizer, nano particle and preparation method and application of polymer photosensitizer and nano particle

Abstract

The invention discloses a polymer photosensitizer, nanoparticles and a preparation method and application of the polymer photosensitizer and the nanoparticles, and belongs to the technical field of biological optical diagnosis and treatment. The polymer comprises SPI and FPI, and SPI nano particles and FPI nano particles are prepared from the polymer. Under the irradiation of low-power laser, the SPI nano particles and the FPI nano particles can generate I-type active oxygen, and have excellent near-infrared two-region fluorescence emission performance. The preparation of the near-infrared two-region fluorescence imaging guided low-power laser triggered photodynamic therapy reagent is realized, a new method is provided for developing a low-power efficient photosensitizer, and the near-infrared two-region fluorescence imaging guided low-power laser triggered photodynamic therapy reagent has a potential application prospect in the field of biomedicine.

Description

Technical Field

[0001] This invention belongs to the field of bio-optical diagnostic and therapeutic technology, and more specifically, relates to a polymer photosensitizer, nanoparticles, their preparation methods and applications. Background Technology

[0002] Photodynamic therapy (PDT) is a novel tumor treatment technology that uses light of a specific wavelength to activate photosensitizers accumulated in tumor tissue, causing a photochemical reaction that produces reactive oxygen species (ROS), thereby precisely destroying cancer cells, inhibiting angiogenesis, and inducing cancer cell death.

[0003] Currently, PDT technology faces two main problems: (1) Most of the photosensitizers developed so far are type II photosensitizers, and they can only exert their therapeutic effect in an oxygen-rich environment, such as sodium porphyrin, hematoporphyrin monomethyl ether, and palipofene. They are highly dependent on oxygen concentration to generate singlet oxygen to kill cancer cells. In contrast, type I photosensitizers have low oxygen dependence and can directly transfer electrons to the substrate after laser activation, generating ·OH and ·O2. - Reactive oxygen species, such as volatile organic compounds, can cause oxidative damage to cancer cells, thereby killing them. (2) Most near-infrared (NIR) organic photosensitizers require laser irradiation at power densities far exceeding the safe level to achieve effective therapeutic effects, while low-power-density laser irradiation results in poor efficacy. This requirement for high power density not only poses safety risks, such as burns and pain, but also severely limits the clinical application of phototherapy (PDT).

[0004] In summary, there is an urgent need to develop novel photosensitizers that can effectively generate type I reactive oxygen species and effectively kill cancer cells under safe, low-power-density laser irradiation. Summary of the Invention

[0005] The purpose of this invention is to address the above-mentioned shortcomings by providing a polymer photosensitizer, nanoparticles, their preparation method, and applications. The polymer nanoparticles exhibit excellent type I photodynamic properties and can be used as an excellent photosensitizer for low-power type I photodynamic therapy, showing potential application prospects in the biomedical field.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: In a first aspect, the present invention provides a polymer photosensitizer, wherein the polymer is FPI or SPI. The structural formula of the FPI is: Where n = 5~100; The structural formula of the SPI is: Where n = 5~100.

[0007] In a second aspect, the present invention provides a method for preparing the polymer photosensitizer described in the first aspect, comprising: The polymer FPI was prepared by mixing 2,7-di(trimethyltin)-4,4,9,9-tetra(p-hexylphenyl)-indarconopyrthiophene, 4,7-bis(2-bromo-5-thienyl)-2,1,3-benzothiadiazole and a palladium catalyst, and adding an organic solvent under nitrogen protection. The synthetic route is as follows: ; The polymer SPI was prepared by mixing 6,6,12,12-tetra(4-hexylphenyl)-s-indenodithienro[3,2-b]thiophene-bis(trimethylstannane), 4,7-bis(2-bromo-5-thienyl)-2,1,3-benzothiadiazole and a palladium catalyst, and adding an organic solvent under nitrogen protection. The synthetic route is as follows: .

[0008] Furthermore, the molar ratio of 2,7-di(trimethyltin)-4,4,9,9-tetra(p-hexylphenyl)-indargenodithiophene, 4,7-bis(2-bromo-5-thienyl)-2,1,3-benzothiadiazole and palladium catalyst is 1:1:(0.1~0.3); the molar ratio of 6,6,12,12-tetra(4-hexylphenyl)-s-indenedithiophene[3,2-b]thiophene-bis(trimethyltinane), 4,7-bis(2-bromo-5-thienyl)-2,1,3-benzothiadiazole and palladium catalyst is 1:1:(0.1~0.3).

[0009] Furthermore, the reaction temperature for preparing polymers FPI and SPI is 110℃~120℃, and the reaction time is 2.5h~4h; stirring is carried out during the reaction.

[0010] Thirdly, the present invention provides a polymer nanoparticle, wherein the polymer nanoparticle is based on the polymer FPI or SPI described in the first aspect, and is prepared by using the amphiphilic polymer F127 and nano-coprecipitation method to obtain FPI nanoparticles or SPI nanoparticles.

[0011] Furthermore, the FPI nanoparticles have a maximum absorption peak of 593 nm, a main emission peak of 724 nm under 660 nm laser excitation, and an emission tail peak that can extend to 1200 nm; the SPI nanoparticles have a main absorption peak of 583 nm, a main emission peak of 752 nm under 660 nm laser excitation, and an emission tail peak that can extend to 1200 nm.

[0012] Furthermore, the mass extinction coefficients of the FPI nanoparticles at 660 nm and 593 nm are 7.52 L·g, respectively.-1 ·cm -1 and 13.8 L·g -1 ·cm -1 The mass extinction coefficients of SPI nanoparticles at 660 nm and 583 nm are 8.3 L·g, respectively. -1 ·cm -1 and 19.4 L·g -1 ·cm -1 .

[0013] Furthermore, the aforementioned polymer nanoparticles were placed in an aqueous solution and subjected to a low power of 20 mW / cm². 2 It exhibits photodynamic properties under 660 nm laser irradiation, and can generate •OH and •O2. - and 1 O2.

[0014] Fourthly, the present invention also provides a method for preparing the polymer nanoparticles described in the third aspect, characterized in that it comprises: The polymer FPI or polymer SPI is dissolved in THF to obtain a THF solution of the polymer; An aqueous solution of F127 was obtained by dissolving the amphiphilic polymer F127 in deionized water. The THF solution of the polymer was added to the F127 aqueous solution to obtain a mixed solution; After ultrasonic vibration, THF is removed from the mixed solution; The mixed solution with THF removed was filtered and concentrated to obtain an aqueous solution of polymer nanoparticles.

[0015] Furthermore, the mass ratio of the polymer FPI to the amphiphilic polymer F127 is 1:(10~30); the molar ratio of the polymer SPI to the amphiphilic polymer F127 is 1:(10~30).

[0016] Furthermore, the filtration is performed using an aqueous filter head; the concentration includes: placing the filtered mixed solution in an ultrafiltration tube and concentrating it on a refrigerated centrifuge.

[0017] Fifthly, the present invention also provides the application of the polymer photosensitizer described in the first aspect in the preparation of a near-infrared II fluorescence imaging reagent under laser irradiation, namely, using its nanoparticle aqueous solution to prepare a NIR-II fluorescence imaging contrast agent.

[0018] In a sixth aspect, the present invention also provides the application of the polymer photosensitizer described in the first aspect in the preparation of a photodynamic therapy reagent triggered by a 660 nm laser, which refers to the use of its nanoparticle aqueous solution to prepare a low-power photodynamic therapy reagent triggered by a 660 nm laser with low power density.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention designs a novel polymer photosensitizer and prepares its nanoparticles. The polymer photosensitizer molecules are easy to synthesize, have easily modifiable structures, and exhibit good reproducibility. The polymer nanoparticle preparation method of the present invention is simple to operate and has good effect. The polymer nanoparticles can effectively generate type I reactive oxygen species under low laser power density laser irradiation and have excellent near-infrared II fluorescence emission performance. They can be used for the preparation of type I photodynamic therapy reagents guided by near-infrared II fluorescence imaging, which can realize the integration of tumor diagnosis and treatment and provide a new method for developing low-power and high-efficiency type I photosensitizers. Attached Figure Description

[0020] Figure 1 The 1H NMR spectrum of the polymer FPI prepared in Example 1 of this invention; Figure 2 The hydrogen NMR spectrum of the polymer SPI prepared in Example 2 of this invention; Figure 3 This is a comparison of the absorption spectra of FPI nanoparticles and SPI nanoparticles of the same concentration in aqueous solution as described in the embodiments of the present invention; Figure 4 The emission comparison spectra of FPI nanoparticles and SPI nanoparticles of the same concentration in aqueous solution as described in the embodiments of the present invention are shown. Figure 5 The mass extinction coefficients of the aqueous solution of FPI nanoparticles prepared in Example 3 of this invention at 660 nm and the maximum absorption peak at 593 nm are shown. Figure 6 The mass extinction coefficients of the aqueous solution of SPI nanoparticles prepared in Example 4 of this invention at 660 nm and the maximum absorption peak at 583 nm are shown. Figure 7 This is a linear fitting graph of the fluorescence intensity corresponding to different concentrations of FPI nanoparticle aqueous solutions described in the embodiments of the present invention; Figure 8 This is a linear fitting graph of the fluorescence intensity corresponding to different concentrations of SPI nanoparticle aqueous solutions described in the embodiments of the present invention; Figure 9 The graph shows the change of 423nm absorbance of the FPI nanoparticles and SPI nanoparticles described in the embodiments of the present invention over time under 660nm laser irradiation. Figure 10 For the generation of FPI nanoparticles prepared in Example 3 of this invention 1 O2 detection graph; Figure 11 For the generation of SPI nanoparticles prepared in Example 4 of this invention 1O2 detection graph; Figure 12 This is a detection graph of •OH generation from FPI nanoparticles prepared in Example 3 of the present invention; Figure 13 This is a detection graph of •OH generation from SPI nanoparticles prepared in Example 4 of the present invention; Figure 14 •O2 is generated from the FPI nanoparticles prepared in Example 3 of this invention. - Detection image; Figure 15 •O2 generation for SPI nanoparticles prepared in Example 4 of this invention - Detection image; Figure 16 The FPI nanoparticles prepared in Example 3 of this invention were co-incubated with cells at a power density of 20 mW / cm². 2 Confocal fluorescence images of live / dead cells stained under 660 nm laser irradiation; Figure 17 The SPI nanoparticles prepared in Example 4 of this invention were co-incubated with cells at a power density of 20 mW / cm². 2 Confocal fluorescence images of live / dead cells stained under 660 nm laser irradiation. Detailed Implementation

[0021] Preferred embodiments of the present invention will now be described in more detail with reference to the accompanying drawings and specific examples.

[0022] In the following description, certain specific details are set forth for the purpose of illustrating various disclosed embodiments in order to provide a thorough understanding of the various disclosed embodiments. However, those skilled in the art will recognize that embodiments may be practiced without one or more of these specific details. In other instances, well-known apparatuses, structures, and techniques associated with this application may not have been shown or described in detail to avoid unnecessarily obscuring the description of the embodiments.

[0023] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0024] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, and the materials and reagents used are commercially available.

[0025] The raw material information used in the specific embodiments is as follows: 2,7-Di(trimethyltin)-4,4,9,9-tetra(p-hexylbenzene)-indarcondithiophene: 98%, Sigma-Aldrich; 4,7-Bis(2-bromo-5-thienyl)-2,1,3-benzothiadiazole: 98%, Sigma-Aldrich; 6,6,12,12-Tetra(4-hexylphenyl)-s-indenodithiopheno[3,2-b]thiophene-bis(trimethylstanane): 98%, Sigma-Aldrich; Tetra(triphenylphosphine)palladium: 98%, Sigma-Aldrich; Toluene: 99%, Sinopharm Reagent; Methanol: 99%, Sinopharm Reagent; Tetrahydrofuran: 99%, Sinopharm Reagent.

[0026] Example 1 This embodiment provides a polymer photosensitizer, which is a polymer FPI, and has the following structure: ; The value of n ranges from 5 to 100.

[0027] The synthetic route for the above polymer FPI is as follows: .

[0028] This embodiment also provides a method for preparing the polymer FPI, including the following steps: 55.5 mg (0.045 mmol) of 2,7-di(trimethyltin)-4,4,9,9-tetra(p-hexylphenyl)-indarconodithiophene (referred to as Compound 1), 20 mg (0.045 mmol) of 4,7-bis(2-bromo-5-thienyl)-2,1,3-benzothiadiazole (referred to as Compound 2), and 12 mg (0.01 mmol) of tetra(triphenylphosphine)palladium were weighed and placed in a polymer reaction flask. Then, 3 mL of toluene was added, and the mixture was stirred vigorously at 118 °C for 3 h under nitrogen protection. After the reaction was complete, excess methanol was added dropwise and stirred until sedimentation. The product was washed three times by filtration and dried to obtain 27.3 mg of black polymer FPI. Figure 1 This is the 1H NMR spectrum of the polymer FPI.

[0029] Example 2 This embodiment provides a polymer photosensitizer, namely polymer SPI, which has the following structure: ; The value of n ranges from 5 to 100.

[0030] The synthetic route for the above polymer SPI is as follows: .

[0031] This embodiment also provides a method for preparing the polymer SPI, including the following steps: 60.5 mg (0.045 mmol) of 6,6,12,12-tetra(4-hexylphenyl)-s-indenodithiopheno[3,2-b]thiophene-bis(trimethylstanane) (referred to as compound 3), 20 mg (0.045 mmol) of 4,7-bis(2-bromo-5-thienyl)-2,1,3-benzothiadiazole (referred to as compound 2), and 12 mg (0.01 mmol) of tetra(triphenylphosphine)palladium were weighed and placed in a polymer reaction flask. Then, 3 mL of toluene was added, and the mixture was stirred vigorously at 118 °C for 3 h under nitrogen protection. After the reaction was completed, excess methanol was added dropwise and stirred until sedimentation. The product was washed three times by filtration and dried to obtain 28.9 mg of black polymer SPI. Figure 2 This is the 1H NMR spectrum of the polymer SPI.

[0032] Example 3 This embodiment provides an FPI nanoparticle based on the polymer FPI described in Example 1, and its preparation method includes the following steps: Weigh 1 mg of polymer FPI and dissolve it in 2 mL of tetrahydrofuran to prepare a polymer FPI solution; Weigh 20 mg of the amphiphilic polymer F127 and dissolve it in 20 mL of deionized water to prepare an F127 solution. Place the F127 solution in a cell disruptor beforehand, then quickly inject the polymer FPI solution into it using a 2.5 mL syringe. Set the sonication time to 3 min and sonicate until completely dissolved.

[0033] After sonication, the solution was stirred overnight in a fume hood to remove residual tetrahydrofuran; then filtered using a 0.22 μm aqueous filter; the filtered solution was then placed in an ultrafiltration tube and concentrated three times in a refrigerated centrifuge at 2700 rpm to obtain a quantitative aqueous solution of FPI nanoparticles.

[0034] Example 4 This embodiment provides SPI nanoparticles based on the polymer SPI described in Example 2, and the preparation method includes the following steps: Weigh 1 mg of polymer SPI and dissolve it in 2 mL of tetrahydrofuran to prepare a polymer SPI solution; Weigh 20 mg of the amphiphilic polymer F127 and dissolve it in 20 mL of deionized water to prepare an F127 solution. F127 solution was pre-placed in a cell disruptor, and polymer SPI solution was quickly injected into it using a 2.5 mL syringe. The sonication time was set to 3 min, and the mixture was sonicated until completely dissolved.

[0035] After sonication, the solution was stirred overnight in a fume hood to remove residual tetrahydrofuran; then filtered using a 0.22 μm aqueous filter; the filtered solution was then placed in an ultrafiltration tube and concentrated three times in a refrigerated centrifuge at 2700 rpm to obtain a quantitative aqueous solution of SPI nanoparticles.

[0036] Figure 3 The images show a comparison of the absorption spectra of FPI nanoparticles and SPI nanoparticles of the same concentration prepared in Examples 3 and 4 in aqueous solution. Figure 4 The emission comparison spectra of FPI nanoparticles and SPI nanoparticles of the same concentration prepared in Examples 3 and 4 in aqueous solution are shown in the figure. As can be seen from the figure, the maximum absorption peak of FPI nanoparticles is 593 nm, and the maximum emission peak is 724 nm under 660 nm laser excitation, with its emission tail peak extending to 1200 nm. The maximum absorption peak of SPI nanoparticles is 583 nm, and the maximum emission peak is 752 nm under 660 nm laser excitation, with its emission tail peak extending to 12000 nm.

[0037] Figure 5 The mass extinction coefficients at 660 nm and the maximum absorption peak at 593 nm were calculated for the FPI nanoparticle aqueous solution prepared in Example 3 of this invention. The calculated mass extinction coefficients of the FPI nanoparticles at 660 nm and 593 nm are 7.52 L·g⁻¹. -1 ·cm -1 and 13.8 L·g -1 ·cm -1 ; Figure 6 For the SPI nanoparticle aqueous solution prepared in this invention, the mass extinction coefficients at 660 nm and the maximum absorption peak at 583 nm were calculated. From the graphs, the mass extinction coefficients of the SPI nanoparticles at 660 nm and 583 nm were calculated to be 8.3 L·g⁻¹. -1 ·cm -1 and 19.4 L·g -1 ·cm -1 The results showed that both FPI nanoparticles and SPI nanoparticles had good light absorption capabilities.

[0038] Fluorescence imaging experiments were performed on the FPI nanoparticles prepared by the method described in Example 3 and the SPI nanoparticles prepared by the method described in Example 4. Solutions of FPI nanoparticles and SPI nanoparticles with concentrations of 12.5 μg / mL, 25 μg / mL, 40 μg / mL, and 50 μg / mL were placed in centrifuge tubes, and the fluorescence intensity was recorded by an NIR-II fluorescence imaging instrument. Figure 7 The linear fitting plot of fluorescence intensity corresponding to different concentrations of FPI nanoparticle aqueous solutions is shown, and its slope is calculated to be 263.3. Figure 8 A linear fitting plot of fluorescence intensity corresponding to different concentrations of SPI nanoparticle aqueous solutions was generated, and the slope was calculated to be 632.3. The ratio of the slopes shows that the fluorescence intensity of SPI nanoparticles is approximately 2.4 times that of FPI nanoparticles, indicating that SPI nanoparticles possess superior fluorescence imaging performance. This demonstrates that introducing more thiophene ring structures into the donor increases the absorbance of the material, further enhances the fluorescence quantum yield, and increases fluorescence brightness.

[0039] The present invention uses 1,3-diphenylisobenzofuran (DPBF) to test the photodynamic properties of the FPI nanoparticles and SPI nanoparticles.

[0040] FPI and SPI nanoparticle solutions were prepared to achieve the same absorbance at 660 nm. A small amount of DPBF powder was dissolved in 1 mL of methanol and then quantitatively added to the aforementioned nanoparticle solutions, resulting in a mixed solution with an absorbance of approximately 1.6 at 423 nm. The significant decrease in absorbance at 423 nm in the mixed solution indicates that both SPI and FPI nanoparticles generated ROS under laser irradiation. By comparing the slope of the absorption peak decline of DPBF at 423 nm, the relative strength of the two nanoparticles' ROS-generating abilities was further determined. Figure 9 To achieve ultra-low power density of 660 nm (1.0 mW / cm²) 2 Under laser irradiation, the absorbance changes at 423 nm of the FPI nanoparticles prepared in Example 3 and the SPI nanoparticles prepared in Example 4 of this invention were plotted. It was found that the absorption decrease intensity of DPBF in the presence of SPI nanoparticles was significantly better than that of FPI nanoparticles, indicating that SPI nanoparticles with a large number of thiophene rings in the donor have better photodynamic performance.

[0041] Figure 10 For the generation of FPI nanoparticles prepared in Example 3 of this invention 1 O2 detection graph. Singlet oxygen probe (SOSG) was used for detection. 1 O2 generation at 660 nm (20 mW / cm²)2 Under laser irradiation, the fluorescence intensity of SOSG at 525 nm gradually increases, indicating that laser irradiation can produce... 1 O2.

[0042] Figure 11 For the generation of SPI nanoparticles prepared in Example 4 of this invention 1 O2 detection graph. Singlet oxygen probe (SOSG) was used for detection. 1 O2 generation at 660 nm (20 mW / cm²) 2 Under laser irradiation, the fluorescence intensity of SOSG at 525 nm gradually increases, indicating that laser irradiation can produce... 1 O2.

[0043] Figure 12 This is a detection graph of •OH generation from the FPI nanoparticles prepared in Example 3 of this invention. Aminophenyl fluorescein (APF) was used to detect •OH generation at 660 nm (20 mW / cm²). 2 Under laser irradiation, the fluorescence intensity of APF at 517 nm gradually increased, indicating that •OH can be generated under laser irradiation.

[0044] Figure 13 This is a detection graph of •OH generation from the SPI nanoparticles prepared in Example 4 of this invention. Aminophenyl fluorescein (APF) was used to detect •OH generation at 660 nm (20 mW / cm²). 2 Under laser irradiation, the fluorescence intensity of APF at 517 nm gradually increased, indicating that •OH can be generated under laser irradiation.

[0045] Figure 14 •O2 is generated from the FPI nanoparticles prepared in Example 3 of this invention. - Detection chart. Diethylhydrogen ether (DHE) was used to detect •O2. - The generation occurs at 660 nm (20 mW / cm). 2 Under laser irradiation, the fluorescence intensity of DHE at 590 nm gradually increases, indicating that •O2 can be generated under laser irradiation. - .

[0046] Figure 15 •O2 generation for SPI nanoparticles prepared in Example 4 of this invention - Detection chart. Diethylhydrogen ether (DHE) was used to detect •O2. - The generation occurs at 660 nm (20 mW / cm). 2 Under laser irradiation, the fluorescence intensity of DHE at 590 nm gradually increases, indicating that •O2 can be generated under laser irradiation. - .

[0047] 4T1 cells at an appropriate density were seeded in confocal dishes and incubated for 24 h. Then, 100 μg / mL FPI and SPI nanoparticles were added to the culture medium mixture, and the cells were incubated again for 1 h. Finally, a 20 mW / cm² incubator was used. 2 The cells were irradiated with a 660 nm laser for 10 min, and then AM and PI were added to stain the irradiated 4T1 cells. After incubation for 24 h, the cell state was photographed using a confocal microscope. Figure 16 The FPI nanoparticles prepared in Example 3 of this invention were co-incubated with 4T1 cells at a power density of 20 mW / cm². 2 The confocal fluorescence images of live / dead cells stained under 660 nm laser irradiation show that FPI nanoparticles, when incubated without light, exhibit green fluorescence, indicating that FPI nanoparticles have good biocompatibility; while those irradiated with laser exhibit red fluorescence, indicating that FPI nanoparticles have excellent tumor cell therapy effects. Figure 17 The SPI nanoparticles prepared in Example 4 of this invention were co-incubated with 4T1 cells at a power density of 20 mW / cm². 2 The image shows confocal fluorescence of live / dead cells stained under 660 nm laser irradiation. As can be seen from the image, cells incubated with SPI nanoparticles but without light irradiation exhibit green fluorescence, indicating that SPI nanoparticles have good biocompatibility; cells irradiated with laser irradiation exhibit red fluorescence, indicating that SPI nanoparticles have excellent tumor cell therapy effects.

[0048] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and principles of the described embodiments, and these modifications and variations should also be considered within the scope of protection of the present invention.

[0049] Unless the context requires otherwise, throughout the specification and claims, the word “comprising” and its variations, such as “including” and “having”, shall be understood to have an open, inclusive meaning, that is, to be interpreted as “including, but not limited to”.

[0050] Throughout this specification, references to "an embodiment" or "an embodiment" indicate that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Therefore, the appearance of "in an embodiment" or "an embodiment" in various places throughout the specification does not necessarily refer to the same embodiment. Furthermore, a particular feature, structure, or characteristic may be combined in any manner in one or more embodiments.

[0051] The singular forms “a” and “the” used in this specification and the appended claims include plural references, unless otherwise clearly stated herein.

Claims

1. A polymer photosensitizer, characterized in that, The polymer is FPI or SPI. The structural formula of the FPI is: Where n = 5~100; The structural formula of the SPI is: Where n = 5~100.

2. A method for preparing the polymer photosensitizer according to claim 1, characterized in that, include: 2,7-Di(trimethyltin)-4,4,9,9-tetra(p-hexylbenzene)-indarconidiothiophene, 4,7-bis(2-bromo-5-thienyl)-2,1,3-benzothiadiazole and palladium catalyst were mixed and an organic solvent was added under nitrogen protection to prepare polymer FPI. The polymer SPI was prepared by mixing 6,6,12,12-tetra(4-hexylphenyl)-s-indenodithiopheno[3,2-b]thiophene-bis(trimethylstanane), 4,7-bis(2-bromo-5-thienyl)-2,1,3-benzothiadiazole and palladium catalyst, adding an organic solvent under nitrogen protection.

3. The method for preparing the polymer according to claim 2, characterized in that, The molar ratio of 2,7-bis(trimethyltin)-4,4,9,9-tetra(p-hexylbenzene)-indargenopyrthiophene, 4,7-bis(2-bromo-5-thienyl)-2,1,3-benzothiadiazole and palladium catalyst is 1:1:(0.1~0.3). And / or, the molar ratio of the 6,6,12,12-tetra(4-hexylphenyl)-s-indenodithiopheno[3,2-b]thiophene-bis(trimethylstanane), 4,7-bis(2-bromo-5-thienyl)-2,1,3-benzothiadiazole and palladium catalyst is 1:1:(0.1~0.3).

4. A polymer nanoparticle, characterized in that, The polymer nanoparticles are FPI nanoparticles or SPI nanoparticles prepared by the amphiphilic polymer F127 and nano-coprecipitation method based on the polymer FPI or SPI described in claim 1.

5. The polymer nanoparticles according to claim 4, characterized in that, The maximum absorption peak of the FPI nanoparticles is 593 nm, and the maximum emission peak is 724 nm when excited by a 660 nm laser. And / or, the maximum absorption peak of the SPI nanoparticles is at 583 nm, and the maximum emission peak is at 752 nm when excited by a 660 nm laser.

6. The polymer nanoparticles according to claim 4, characterized in that, In aqueous solution, under excitation by a 660 nm light source, the emission tail peak of the polymer nanoparticles can extend to 1200 nm.

7. A method for preparing polymer nanoparticles according to claim 4, characterized in that, include: The polymer FPI or polymer SPI is dissolved in THF to obtain a THF solution of the polymer; An aqueous solution of F127 was obtained by dissolving the amphiphilic polymer F127 in deionized water. The THF solution of the polymer was added to the F127 aqueous solution to obtain a mixed solution; After ultrasonic vibration, THF is removed from the mixed solution; The mixed solution with THF removed was filtered and concentrated to obtain an aqueous solution of polymer nanoparticles.

8. The method for preparing polymer nanoparticles according to claim 7, characterized in that, The filtration is performed using a water-based filter head; And / or, the concentration includes: placing the filtered mixed solution in an ultrafiltration tube and concentrating it on a refrigerated centrifuge.

9. The use of the polymer photosensitizer of claim 1 in the preparation of a near-infrared II fluorescence imaging reagent under laser irradiation.

10. The use of the polymer photosensitizer of claim 1 in the preparation of a photodynamic therapy reagent triggered by a 660 nm laser.

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