Thiophene thiazolyl photosensitizer as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of biochemical materials, and particularly relates to a thiophene thiazolyl photosensitizer as well as a preparation method and application thereof. The thiophene thiazolyl photosensitizer provided by the invention has a structure as shown in a formula I or a formula II, and has near-infrared two-region fluorescence imaging and photodynamic / photo-thermal synergistic cancer cell killing activity. Once exposed to 660 nm laser, the cell activity can be obviously reduced along with the increase of the concentration of the photosensitizer nanoparticles, and the tumor cells can be well killed even at an extremely low concentration (2 [mu] M). The thiophene thiazolyl photosensitizer has bright NIR-II emission which is successfully extended to 1300nm, also has excellent light / heat stability and effective ROS (reactive oxygen species) generation capability, and is beneficial to in-vivo near-infrared second region (greater than 900nm) fluorescence bioimaging, light diagnosis and treatment and anticancer application research. Formulae I and II

Description

Technical Field

[0001] This invention belongs to the field of biochemical materials technology, specifically relating to a thiophenthiazole-based photosensitizer, its preparation method, and its application. Background Technology

[0002] Cancer, with its rapid proliferation, spread, and metastasis, poses a serious threat to human health and life. Traditional anti-cancer strategies such as radiotherapy, chemotherapy, and surgery suffer from poor efficacy and significant side effects, prompting the emergence of precision medicine and personalized medicine. The concept of integrating diagnosis and treatment has become an important direction for solving these problems. However, existing diagnostic procedures such as magnetic resonance imaging, X-rays, positron emission tomography (PET), and ultrasound imaging are limited by radioactivity, low sensitivity, and spatiotemporal resolution, making it difficult to meet the needs of real-time guidance for surgery or treatment. Against this backdrop, phototherapy diagnostic strategies based on fluorescence imaging (FLI), photoacoustic imaging (PAI), photodynamic therapy (PDT), and photothermal therapy (PTT) have emerged, enabling precise diagnosis of target areas and selective treatment of lesions. Near-infrared II (NIR-II) organic fluorescent molecules are ideal choices for high-performance fluorescence imaging reagents due to their deep tissue penetration and low autofluorescence interference. High-sensitivity fluorescence imaging has been extensively explored in the field of tumor phototherapy. Currently, many organic phototherapy reagents used in bioimaging and therapy are based on near-infrared I (NIR-I, 650~1000nm) indocyanine green (ICG) dyes. However, these dyes generally suffer from poor photostability, low photothermal conversion efficiency, and low reactive oxygen species (ROS) production efficiency, limiting their further application. Therefore, developing multifunctional organic phototherapy reagents with near-infrared II (NIR-II, 1000~1700nm) fluorescence emission, excellent photostability, high photothermal conversion efficiency, and high ROS yield is an urgent priority. Summary of the Invention

[0003] In view of this, the purpose of this invention is to provide a thienothiazole-based photosensitizer, its preparation method, and its application. The thienothiazole-based photosensitizer provided by this invention possesses both near-infrared II fluorescence imaging and photodynamic / photothermal synergistic cancer cell killing activity, and exhibits excellent light / thermal stability and reactive oxygen species generation capacity, making it suitable for in vivo fluorescence imaging and anti-cancer diagnosis and treatment.

[0004] This invention provides a thiophenthiazole-based photosensitizer having the structure shown in Formula I or Formula II: Formula I, Formula II; In Equation I, R1 is , , or In Equation II, R2 is or .

[0005] This invention also provides a method for preparing the thiophenthiazole-based photosensitizer described in the above technical solution, comprising the following steps: A thiophene compound having the structure shown in Formula III, N-bromosuccinimide, thiourea, and an alcohol solvent were mixed and subjected to a Hantzsch thiazole cyclization reaction under a protective atmosphere to obtain intermediate 1 having the structure shown in Formula IV. Formula III, Formula IV; Intermediate 1, which has the structure shown in Formula IV, tert-butyl nitrite, cuprous bromide, and a first organic solvent are mixed and subjected to a substitution reaction under a protective atmosphere to obtain intermediate 2, which has the structure shown in Formula V. Formula V; The intermediate 2 having the structure shown in Formula V, malononitrile, acetate, and a second organic solvent are mixed and subjected to a condensation reaction under a protective atmosphere to obtain the intermediate 3 having the structure shown in Formula VI. Formula VI; The intermediate 3 having the structure shown in Formula VI, the organotin compound having the structure shown in Formula VII or Formula VIII, the palladium catalyst, and the third organic solvent are mixed and subjected to a Stieler reaction under a protective atmosphere to obtain a thiophenethiazolyl photosensitizer. VII, VIII; In Equation VII, R1 is defined as in Equation I, and in Equation VIII, R2 is defined as in Equation II.

[0006] Preferably, the molar ratio of the thiophene compound, N-bromosuccinimide, and thiourea is 1:2~3:2~3.

[0007] Preferably, the temperature of the Hantzsch thiazole cyclization reaction is 50~100℃.

[0008] Preferably, the molar ratio of intermediate 1, tert-butyl nitrite, and cuprous bromide is 1:2 to 3:3.

[0009] Preferably, the temperature of the substitution reaction is 50~80°C.

[0010] Preferably, the molar ratio of intermediate 2, malononitrile, and acetate is 1:5~10:2~3.

[0011] Preferably, the molar ratio of intermediate 3 to organotin compound is 1~2.2:0.2~1; and the temperature of the Stieler reaction is 90~110℃.

[0012] The present invention also provides the application of the thiophenthiazole-based photosensitizer described above in the preparation of products for diagnosing and / or treating tumors.

[0013] Preferably, the dosage form of the diagnostic and / or therapeutic tumor treatment product includes nanoparticles, tablets, capsules, injections, or suspensions.

[0014] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a thiophene-thiazole-based photosensitizer with the structure shown in Formula I or Formula II. Thiazole, as an electron-deficient five-membered heterocycle, can be used to construct the electron acceptor core, while the cyano group, as an electron-withdrawing group, can be used to enhance the electron-withdrawing performance of the acceptor. The novel thiophene-thiazole-based electron acceptor designed and synthesized in this invention enhances the acceptor's electron-withdrawing ability through the introduction of thiophene and cyano groups. Simultaneously, triphenylamine, dimethoxytriphenylamine, or indahedron-dithiophene series compounds with excellent electron-donating properties are selected as electron donors to form a typical donor-acceptor structure. Because the thiophene / thiazole heterocycle contains sulfur atoms, the p orbitals of its heteroatoms can conjugate with the π orbitals of the ring, effectively regulating the frontier orbital (HOMO, LUMO) energy levels of the molecule. Simultaneously, the sulfur atoms also facilitate the influence of intermolecular interactions (such as weak coordination, van der Waals interactions, etc.) on the assembly behavior and optical properties of nanoparticles. After coating the compound into polyethylene glycol to form nanoparticles via precipitation, the photosensitizer of this invention exhibits bright near-infrared II emission, successfully extending to 1300 nm. Photophysical testing results show that the photosensitizer of this invention has good photothermal properties and reactive oxygen species generation properties. In subsequent biological experiments, it demonstrated excellent tumor enrichment in tumor-bearing mice and synergistic photodynamic and photothermal therapeutic effects on cancer guided by near-infrared II fluorescence. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 The UV absorption spectrum of SFTPO nanoparticles in water; Figure 2 The fluorescence emission pattern of SFTPO nanoparticles in water; Figure 3 This is a particle size distribution diagram of SFTPO nanoparticles in water; Figure 4 Photothermal power dependence diagram of SFTPO nanoparticles; Figure 5 Photothermal stability diagram of SFTPO nanoparticles; Figure 6 The diagram shows the reactive oxygen generation capacity of SFTPO nanoparticles. Figure 7 The images show NIR-II fluorescence at different time points after injection of SFTPO-NPs in tumor-bearing mice (A) and the fluorescence signal intensity at the corresponding tumor sites (B). Figure 8 The particle size distribution diagrams are for SFPHIDT and 2SFPHIDT nanoparticle solutions. Figure 9 The photothermal curves of SFPHIDT and 2SFPHIDT-NPs under 660 nm laser irradiation at different powers are shown. Detailed Implementation

[0017] This invention provides a thiophenthiazole-based photosensitizer having the structure shown in Formula I or Formula II: Formula I, Formula II; In Equation I, R1 is , , or In Equation II, R2 is or .

[0018] In this invention, the thiophenthiazole photosensitizer is preferably any structure of formula Ia~Id or II-a~II-b: Formula Ia; Formula Ib; Formula Ic; FormulaId; Formula II-a; Formula II-b.

[0019] This invention provides a method for preparing the thiophenthiazole-based photosensitizer described in the above technical solution, comprising the following steps: A thiophene compound having the structure shown in Formula III, N-bromosuccinimide, thiourea, and an alcohol solvent were mixed and subjected to a Hantzsch thiazole cyclization reaction under a protective atmosphere to obtain intermediate 1 having the structure shown in Formula IV. Formula III, Formula IV; Intermediate 1, which has the structure shown in Formula IV, tert-butyl nitrite, cuprous bromide, and a first organic solvent are mixed and subjected to a substitution reaction under a protective atmosphere to obtain intermediate 2, which has the structure shown in Formula V. Formula V; The intermediate 2 having the structure shown in Formula V, malononitrile, acetate, and a second organic solvent are mixed and subjected to a condensation reaction under a protective atmosphere to obtain the intermediate 3 having the structure shown in Formula VI. Formula VI; The intermediate 3 having the structure shown in Formula VI, the organotin compound having the structure shown in Formula VII or Formula VIII, the palladium catalyst, and the third organic solvent are mixed and subjected to a Stieler reaction under a protective atmosphere to obtain a thiophenethiazolyl photosensitizer. VII, VIII.

[0020] In Equation VII, R1 is defined as in Equation I, and in Equation VIII, R2 is defined as in Equation II.

[0021] Unless otherwise specified, all materials and equipment used in this invention are commercially available products in the field.

[0022] In this invention, the protective atmosphere is preferably a nitrogen atmosphere or an argon atmosphere.

[0023] In this invention, a thiophene compound having the structure shown in Formula III, N-bromosuccinimide, thiourea, and an alcohol solvent are mixed and subjected to a Hantzsch thiazole cyclization reaction under a protective atmosphere to obtain intermediate 1 having the structure shown in Formula IV.

[0024] The present invention does not have any special requirements for the mixing method of the thiophene compound, N-bromosuccinimide, thiourea and alcohol solvent; any mixing method known to those skilled in the art can be used.

[0025] In this invention, the molar ratio of the thiophene compound, N-bromosuccinimide and thiourea is preferably 1:2~3:2~3, and more specifically, it can be 1:2.5:2.8.

[0026] In this invention, the alcohol solvent preferably includes methanol or ethanol.

[0027] In this invention, the preferred temperature for the Hantzsch thiazole cyclization reaction is 50-100°C, more preferably 50-80°C, and specifically 65°C. The Hantzsch thiazole cyclization reaction is preferably carried out under stirring or reflux conditions. This invention does not have a specific limitation on the stirring rate, as long as it is sufficient to achieve uniform stirring. This invention preferably monitors the reaction using a TLC plate (thin-layer chromatography plate) until the thiophene compound completely disappears.

[0028] In this invention, the Hantzsch thiazole cyclization reaction preferably further includes: performing a first post-treatment on the obtained reaction solution. The first post-treatment preferably includes the following steps: extracting and concentrating the obtained reaction solution to obtain a concentrate; performing column chromatography on the concentrate to remove the solvent, obtaining intermediate 1. The extraction preferably includes: adding a saturated ammonium chloride aqueous solution and dichloromethane to the reaction solution for extraction, separating the organic phase, and then adding dichloromethane to extract the remaining aqueous phase twice, combining the organic phases; the volume ratio of dichloromethane to saturated ammonium chloride aqueous solution used in each extraction is preferably 1:1; the eluent used for column chromatography is preferably a mixture of petroleum ether and ethyl acetate, with a volume ratio of petroleum ether to ethyl acetate preferably 2:1. This invention does not specifically limit the method of solvent removal; conventional solvent removal methods, such as rotary evaporation, are acceptable.

[0029] After obtaining intermediate 1 having the structure shown in Formula IV, the present invention mixes intermediate 1 having the structure shown in Formula IV, tert-butyl nitrite, cuprous bromide and a first organic solvent, and carries out a substitution reaction under a protective atmosphere to obtain intermediate 2 having the structure shown in Formula V.

[0030] In this invention, the first organic solvent is preferably acetonitrile, toluene, or acetone.

[0031] In this invention, the molar ratio of intermediate 1, tert-butyl nitrite and cuprous bromide is preferably 1:2 to 3:3, specifically 1:2.5:3 or 1:3:3.

[0032] In this invention, the temperature of the substitution reaction is preferably 50-80°C, more preferably 50-70°C, and specifically 60°C or 65°C. This invention does not have a specific time limit for the substitution reaction; it is preferred to monitor the reaction using a TLC plate until intermediate 1 completely disappears.

[0033] In this invention, the substitution reaction preferably further includes: performing a second post-treatment on the obtained substitution reaction solution; except that the volume ratio of petroleum ether to ethyl acetate in the eluent for column chromatography is 5:1, the second post-treatment is preferably the same as the first post-treatment step, and will not be described again here.

[0034] After obtaining intermediate 2, the present invention mixes intermediate 2 having the structure shown in formula V, malononitrile, acetate and a second organic solvent, and carries out a condensation reaction under a protective atmosphere to obtain intermediate 3 having the structure shown in formula VI.

[0035] In this invention, the molar ratio of intermediate 2, malononitrile and acetate is preferably 1:5~10:2~3, specifically 1:10:3.

[0036] In this invention, the acetate preferably includes sodium acetate and ammonium acetate.

[0037] In this invention, the second organic solvent is preferably trichloromethane or dichloromethane.

[0038] In this invention, the temperature of the condensation reaction is preferably -10~10℃, more preferably -10~0℃, and specifically 0℃ or 5℃. This invention does not have a specific limitation on the time of the condensation reaction; it is preferred to monitor the reaction using a TLC plate until intermediate 2 completely disappears.

[0039] In this invention, the condensation reaction preferably further includes a third post-treatment of the obtained reaction solution; the third post-treatment is preferably the same as the second post-treatment step, and will not be described again here.

[0040] After obtaining intermediate 3, the present invention mixes intermediate 3 having the structure shown in Formula VI, an organotin compound having the structure shown in Formula VII or Formula VIII, a palladium catalyst, and the fourth organic solvent, and carries out a Stieler reaction under a protective atmosphere to obtain a thiophenethiazole-based photosensitizer.

[0041] In this invention, the organotin compound preferably includes N,N-diphenyl-4-(tributyltinyl)aniline, 4-methoxy-N-(4-methoxyphenyl)-N-(3-tributyltinyl)phenyl)aniline, (indalnar[1,2-b:5,6-b]dithiophene-2,7-diyl)bis[1,1,1-tributyl]tin or 2,7-bis(tributyltin)-4,4,9,9-tetra(p-hexylphenyl)-indalnardithiophene, which can be purchased directly through commercial channels.

[0042] In this invention, the molar ratio of intermediate 3 to organotin compound is preferably 1~2.2:0.2~1, specifically 1:0.5.

[0043] In this invention, the palladium catalyst is preferably tetra(triphenylphosphine)palladium, and the molar ratio of the intermediate 3 to the palladium catalyst is preferably 1:0.05~0.1.

[0044] In this invention, the fourth organic solvent preferably includes toluene, DMF, and DMSO.

[0045] In this invention, the temperature of the Stieler reaction is preferably 90~110℃, more preferably 100~110℃, and specifically 100℃ or 105℃. This invention does not have a specific limitation on the time of the Stieler reaction; it is preferred to monitor the reaction using a TLC plate until intermediate 3 completely disappears.

[0046] In this invention, the process after the Stieler reaction preferably includes a fourth post-treatment of the resulting reaction solution; the fourth post-treatment is preferably the same as the second post-treatment step, and will not be described in detail here.

[0047] The present invention also provides the application of the thiophenthiazole photosensitizer described above in the preparation of products for diagnosing and / or treating tumors.

[0048] In this invention, the dosage form of the product for diagnosing and / or treating tumors preferably includes nanoparticles, tablets, capsules, injections, or suspensions.

[0049] The thiophenthiazole photosensitizer described in this invention can be used to prepare near-infrared II guided photothermal / photodynamic anticancer drugs.

[0050] In this invention, the tumor includes, but is not limited to, breast cancer, stomach cancer, esophageal cancer, liver cancer, uterine cancer, or lung cancer.

[0051] This invention designs novel thiophene-thiazolyl electron acceptors with different structures. The electron-withdrawing ability of the acceptor is enhanced by introducing a cyano group. Simultaneously, triphenylamine, dimethoxytriphenylamine, or indahedron-dithiophene series compounds with excellent electron-donating properties are selected as electron donors to form typical donor-acceptor structures. After being coated into nanoparticles with polyethylene glycol, these photosensitizers all exhibit bright near-infrared II emission, successfully extending to 1300 nm. Photophysical testing results show that the photosensitizers of this invention possess good photothermal properties and reactive oxygen species generation capabilities. In subsequent biological experiments, they demonstrated excellent tumor enrichment in tumor-bearing mice and synergistic photodynamic and photothermal therapeutic effects guided by near-infrared II fluorescence in cancer treatment.

[0052] To further illustrate the present invention, the thiophenethiazole-based photosensitizer, its preparation method, and its application provided by the present invention will be described in detail below with reference to the accompanying drawings and embodiments, but these should not be construed as limiting the scope of protection of the present invention.

[0053] Example 1 Thiophenethiazole-based photosensitizers were prepared according to the following reaction formula: (1) Compound 1 (10 mmol), N-bromosuccinimide (i.e., NBs, 25 mmol), thiourea (28 mmol) and ethanol were mixed and refluxed at 65 °C under nitrogen protection. The reaction process was monitored by TLC plate until compound 1 disappeared completely. The resulting reaction solution was mixed with saturated ammonium chloride aqueous solution and dichloromethane for extraction. After separating the organic phase, the remaining aqueous phase was extracted twice with dichloromethane. The obtained organic phases were combined and concentrated, and purified by silica gel column chromatography. The eluent used was petroleum ether and ethyl acetate (volume ratio of petroleum ether and ethyl acetate was 2:1). Then the solvent in the obtained column chromatography product was evaporated to dryness to obtain 1.5 g of yellow solid (compound 2). The calculated yield was 72%. (2) Compound 2 (5 mmol), tert-butyl nitrite (15 mmol), cuprous bromide (15 mmol) and acetonitrile were mixed and refluxed at 65 °C under nitrogen protection. The reaction process was monitored by TLC plate until compound 2 disappeared completely. The resulting reaction solution was mixed with saturated ammonium chloride aqueous solution and dichloromethane for extraction. After separating the organic phase, the remaining aqueous phase was extracted twice with dichloromethane. The obtained organic phases were combined and purified by silica gel column chromatography. The eluent used was petroleum ether and ethyl acetate (volume ratio of petroleum ether and ethyl acetate was 5:1). The solvent in the obtained column chromatography product was then evaporated to dryness to obtain 0.8 g of yellow solid (compound 3). The calculated yield was 59%. (3) Compound 3 (1 mmol), malononitrile (10 mmol), sodium acetate (3 mmol) and chloroform were mixed and stirred at 0 °C under nitrogen protection. The reaction process was monitored by TLC plate until compound 3 disappeared completely. The resulting reaction solution was mixed with saturated ammonium chloride aqueous solution and dichloromethane for extraction. After separating the organic phase, the remaining aqueous phase was extracted twice with dichloromethane. The obtained organic phases were combined and purified by silica gel column chromatography. The eluent used was petroleum ether and ethyl acetate (volume ratio of petroleum ether and ethyl acetate was 5:1). The solvent in the obtained column chromatography product was then evaporated to dryness to obtain 0.1 g of red solid (compound 4). The calculated yield was 32%. (4) Compound 4 (1 mmol), 4-methoxy-N-(4-methoxyphenyl)-N-(3-tributyltinyl)phenyl)aniline (0.5 mmol), tetra(triphenylphosphine)palladium (0.1 mmol) and toluene were mixed and stirred at 100 °C under nitrogen protection. The resulting reaction solution was mixed with saturated ammonium chloride aqueous solution and dichloromethane for extraction. After separating the organic phase, the remaining aqueous phase was extracted twice with dichloromethane. The obtained organic phases were combined and purified by silica gel column chromatography. The eluent used was petroleum ether and ethyl acetate (volume ratio of petroleum ether and ethyl acetate was 5:1). The solvent in the obtained column chromatography product was then evaporated to dryness to obtain 0.4 g of dark green solid (denoted as SFTPO). The yield was calculated to be 72%.

[0054] The resulting dark green solid was characterized, and the specific data are as follows: 1H NMR (600 MHz, Chloroform-d) δ 7.96 (d, J=1.8 Hz, 1H), 7.83 (d, J=8.5 Hz, 2H), 7.30 (d, J=1.8 Hz, 1H), 7.16 (d, J=8.8 Hz, 4H), 6.92 (d, J=8.5Hz, 4H), 6.89 (d, J=8.7 Hz, 2H), 3.85 (s, 6H). The characterization data shows that the resulting dark green solid has the structure shown in SFTPO.

[0055] The compound was encapsulated in polyethylene glycol to form nanoparticles using a nanoprecipitation method. The obtained compounds SFTPO (1 mg) and DSPE-mPEG2000 (3 mg) were dissolved separately in 1 mL of tetrahydrofuran (THF) and mixed thoroughly. Under sonication, the mixture was injected into 9 mL of double-distilled water and sonicated for 5 min. After sonication, the solution was transferred to a dialysis bag (molecular weight cutoff of 3600) and dialyzed continuously with deionized water for 24 h, changing the water every 4 h. After all the THF had been dialyzed out, the solution was filtered through a 0.45 μm filter membrane. The prepared nanoparticles were concentrated and recalibrated before use.

[0056] Performance testing: (1) Photoluminescence ability test of photosensitizer: 20 μL of SFTPO nanoparticle aqueous solution (2mM) was added to 2 mL of water to obtain 20 μM SFTPO solution, and the absorption spectrum and fluorescence spectrum of the mixed solution were measured.

[0057] Figure 1 The absorption spectrum of 20 μM SFTPO in aqueous solution; Figure 2 The fluorescence spectrum of 20 μM SFTPO in aqueous solution is given by... Figure 1 and Figure 2 It can be seen that under 660 nm excitation light, SFTPO emits fluorescence at 1000 nm and has a Stokes shift of 400 nm, indicating that SFTPO has good luminescence ability.

[0058] (2) Photosensitizer aggregate particle size test: 40 μL of SFTPO nanoparticle aqueous solution (1 mM) was added to 2 mL of PBS solution (5 mM, pH 7.4) to obtain a 20 μM SFTPO nanoparticle solution, and the particle size distribution of the nanoparticle solution was measured.

[0059] Figure 3 The particle size distribution of the SFTPO nanoparticle solution. Figure 3 It can be seen that the particle size distribution of aggregated SFTPO nanoparticles in aqueous solution is concentrated at around 100 nm, indicating that SFTPO nanoparticles can passively target tumor cells through retention enhancement effect (EPR enhancement).

[0060] (3) Photothermal performance test of photosensitizer: 40 μL of SFTPO nanoparticle aqueous solution (1 mM) was added to 2 mL of PBS solution (5 mM, pH 7.4) to obtain 20 μM SFTPO nanoparticle solution, and the change of solution temperature under different power 660nm laser irradiation was measured.

[0061] Figure 4 This diagram shows the temperature changes and corresponding photothermal conversion efficiencies of the SFTPO nanoparticle solution under irradiation with different powers of a 660nm laser. Figure 4 It can be seen that SFTPO nanoparticles have good photothermal properties in aqueous solution, and the photothermal conversion efficiency of SFTPO is calculated to be 65.9%.

[0062] (4) Stability test of photosensitizer: 40 μL of SFTPO nanoparticle aqueous solution (1 mM) was added to 2 mL PBS solution (5 mM, pH 7.4) to obtain 20 μM SFTPO nanoparticle solution. The solution temperature was measured after irradiation with 0.5W 660nm laser for 6 min and cooling for 6 min, and after 5 cycles.

[0063] Figure 5 This is a temperature change graph for the SFTPO nanoparticle solution. Figure 5 It can be seen that SFTPO nanoparticles remain stable after 5 cycles in aqueous solution, indicating that SFTPO nanoparticles have good stability.

[0064] (5) Test of reactive oxygen species generation capacity of photosensitizer: 40 μL of SFTPO nanoparticle aqueous solution (1 mM) was added to 2 mL PBS solution (5 mM, pH 7.4) to obtain 20 μM SFTPO nanoparticle solution. The reactive oxygen species scavenger 2',7'-dichlorodihydrofluorescein (DCFH) was added to the above solution. Using 489 nm as the excitation light source, the fluorescence spectrum of the mixed solution at 500~600 nm was measured. Then, the mixed solution was irradiated with a solar simulator equipped with a 400 nm filter, and the fluorescence spectrum of the mixed solution at 500~600 nm was measured as a function of irradiation time.

[0065] Figure 6 The fluorescence intensity at 530 nm changes with illumination time. From... Figure 6 It can be seen that as the illumination time increases, the fluorescence intensity of the reactive oxygen species scavenger DCFH gradually increases and eventually reaches a plateau and remains stable, indicating that SFTPO has the ability to generate reactive oxygen species and is a potential photodynamic photosensitizer.

[0066] (6) Test of NIR-II fluorescence imaging capability of nano-imaging reagent SFTPO-NPs on mouse tumors: 100 µL of SFTPO-NPs with a concentration of 300 µmol / L was injected into BALBC / b mice via the tail vein, and then in vivo fluorescence imaging of the mice was performed using a near-infrared II small animal in vivo imaging system. The excitation light source was the illumination source of the near-infrared II small animal in vivo imaging system (16.5 mW cm⁻¹). -2 ).

[0067] Figure 7 Image A shows NIR-II fluorescence images of tumor-bearing mice at different time points (0, 1, 5, 12, 24, 36, 72 h) after injection of SFTPO-NPs. Image B shows the fluorescence signal intensity corresponding to the tumor site, indicating that the molecules can be enriched in the tumor.

[0068] Example 2 C4 (1.1 mmol), IDT66 (1 mmol), tetrakis(triphenylphosphine)palladium (0.2 mmol), and toluene (10 mL) were added to a 100 mL reaction flask and stirred at 100 °C for 24 h under nitrogen protection. After the reaction was completed, the organic phase was concentrated under reduced pressure, and the crude product was purified by silica gel chromatography (petroleum ether / dichloromethane = 10:1, v / v).

[0069] C4 (2.2 mmol), IDT65 (1 mmol), tetrakis(triphenylphosphine)palladium (0.2 mmol), and toluene (10 mL) were added to a 100 mL reaction flask and stirred at 100 °C for 24 h under nitrogen protection. After the reaction was completed, the resulting organic phase was concentrated under reduced pressure, and the crude product was purified by silica gel chromatography (petroleum ether / dichloromethane = 10:1, v / v).

[0070] SFPHIDT: Dark green solid, yield 60%. 1H NMR (600 MHz, Chloroform-d) δ 7.33(d, J = 5.9 Hz, 0H), 7.18 (dd, J = 8.3, 4.1 Hz, 2H), 7.10 (dd, J = 13.3, 8.0Hz, 2H), 2.62 – 2.56 (m, 2H), 1.62 (d, J = 20.0 Hz, 1H), 1.39 – 1.33 (m, 2H), 1.33 (s, 1H), 1.32 (s, 3H), 0.92 – 0.87 (m, 3H). 13C NMR (151 MHz, Chloroform-d) δ 157.28, 157.09, 141.97, 141.65, 141.60, 140.89, 137.54,137.33, 133.48, 128.88, 128.73, 128.57, 128.37, 127.82, 127.78, 125.59,123.27, 118.59, 117.89, 117.51, 113.63, 63.12, 62.79, 35.54, 31.68, 31.24,29.09, 29.07, 22.55, 14.01. HRMS (MALDI-TOF): m / z: [M+H]+ calcd for C 75 H 75 N3S4:1145.4844; found:1146.4929. 2SFPHIDT: Dark green solid, yield 40%. 1H NMR (600 MHz, Chloroform-d) δ 7.99(s, 1H), 7.65 (s, 1H), 7.56 (s, 1H), 7.33 (s, 1H), 7.19 (d, J = 7.9 Hz, 4H),7.14 (d, J = 8.1 Hz, 4H), 0.90 (d, J = 6.4 Hz, 6H). 13C NMR (151 MHz, Chloroform-d) δ 158.12,142.26, 140.54, 137.26, 128.70, 128.60, 128.47, 127.83, 127.71, 125.40,63.22, 35.54, 31.68, 31.24, 29.68, 29.07, 22.55, 14.02.HRMS (MALDI-TOF): m / z:[M+H]+ calcd for C 86 H 76 N6S6: 1384.4456; found:1385.4531. The compound was encapsulated in polyethylene glycol to form nanoparticles using a nanoprecipitation method. The obtained compounds SFPHIDT or 2SFPHIDT (1 mg) and DSPE-mPEG2000 (3 mg) were dissolved in 1 mL of tetrahydrofuran (THF) and mixed thoroughly. Under sonication, the mixture was injected into 9 mL of double-distilled water and sonicated for 5 min. After sonication, the solution was transferred to a dialysis bag (molecular weight cutoff of 3600) and dialyzed continuously with deionized water for 24 h, changing the water every 4 h. After all THF was dialyzed out, the solution was filtered through a 0.45 μm filter membrane. The prepared nanoparticles were concentrated and recalibrated before use.

[0071] Performance testing: (1) Photosensitizer aggregate particle size test: 40 μL of SFPHIDT or 2SFPHIDT nanoparticles aqueous solution (1 mM) was added to 2 mL of PBS solution (5 mM, pH 7.4) to obtain 20 μM SFPHIDT or 2SFPHIDT nanoparticle solution, and the particle size distribution of the nanoparticle solution was determined.

[0072] Figure 8 This is a particle size distribution diagram of SFPHIDT and 2SFPHIDT nanoparticle solutions. Figure 8 It is known that the particle size distribution of aggregated SFPHIDT or 2SFPHIDT nanoparticles in aqueous solution is concentrated at around 100 nm, indicating that SFPHIDT or 2SFPHIDT nanoparticles can passively target tumor cells through retention enhancement effect (EPR enhancement).

[0073] (2) Photothermal performance test of photosensitizer: 40 μL of SFPHIDT or 2SFPHIDT nanoparticles aqueous solution (1 mM) was added to 2 mL of PBS solution (5 mM, pH 7.4) to obtain 20 μM SFPHIDT or 2SFPHIDT nanoparticle solution, and the change in solution temperature under irradiation with different power 660nm laser was measured.

[0074] Figure 9 The photothermal curves of SFPHIDT (left) and 2SFPHIDT-NPs (right) under 660nm laser irradiation at different powers are shown. Figure 9 It is known that SFPHIDT and 2SFPHIDT nanoparticles have good photothermal properties in aqueous solution, and the maximum temperature rise can reach above 75℃.

[0075] The thiophene-thiazole photosensitizer provided by this invention has both near-infrared II fluorescence imaging and photodynamic / photothermal synergistic cancer cell killing activity. It can kill tumor cells efficiently at low concentrations under 660 nm laser, and has excellent light / thermal stability and reactive oxygen species generation ability, making it suitable for in vivo fluorescence imaging and anti-cancer diagnosis and treatment.

[0076] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, not all embodiments. People can obtain other embodiments based on the present invention without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A thiophenthiazole-based photosensitizer, characterized in that, It has the structure shown in Equation I or Equation II: Formula I, Formula II; In Equation I, R1 is , , or In Equation II, R2 is or .

2. The method for preparing the thiophenthiazole-based photosensitizer according to claim 1, characterized in that, Includes the following steps: A thiophene compound having the structure shown in Formula III, N-bromosuccinimide, thiourea, and an alcohol solvent were mixed and subjected to a Hantzsch thiazole cyclization reaction under a protective atmosphere to obtain intermediate 1 having the structure shown in Formula IV. Formula III, Formula IV; Intermediate 1, which has the structure shown in Formula IV, tert-butyl nitrite, cuprous bromide, and a first organic solvent are mixed and subjected to a substitution reaction under a protective atmosphere to obtain intermediate 2, which has the structure shown in Formula V. Formula V; The intermediate 2 having the structure shown in Formula V, malononitrile, acetate, and a second organic solvent are mixed and subjected to a condensation reaction under a protective atmosphere to obtain the intermediate 3 having the structure shown in Formula VI. Formula VI; The intermediate 3 having the structure shown in Formula VI, the organotin compound having the structure shown in Formula VII or Formula VIII, the palladium catalyst, and the third organic solvent are mixed and subjected to a Stieler reaction under a protective atmosphere to obtain a thiophenethiazolyl photosensitizer. VII, VIII: In Equation VII, R1 is defined as in Equation I, and in Equation VIII, R2 is defined as in Equation II.

3. The preparation method according to claim 2, characterized in that, The molar ratio of the thiophene compound, N-bromosuccinimide, and thiourea is 1:2~3:2~3.

4. The preparation method according to claim 2 or 3, characterized in that, The Hantzsch thiazole cyclization reaction was carried out at a temperature of 50–100 °C.

5. The preparation method according to claim 2, characterized in that, The molar ratio of intermediate 1, tert-butyl nitrite, and cuprous bromide is 1:2 to 3:

3.

6. The preparation method according to claim 2 or 5, characterized in that, The temperature for the substitution reaction is 50~80℃.

7. The preparation method according to claim 2, characterized in that, The molar ratio of intermediate 2, malononitrile, and acetate is 1:5~10:2~3.

8. The preparation method according to claim 2, characterized in that, The molar ratio of intermediate 3 to organotin compound is 1~2.2:0.2~1; the temperature of the Stieler reaction is 90~110℃.

9. The use of the thiophenthiazole photosensitizer of claim 1 in the preparation of products for diagnosing and / or treating tumors.

10. The application according to claim 9, characterized in that, The dosage forms of the diagnostic and / or therapeutic tumor products include nanoparticles, tablets, capsules, injections, or suspensions.

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