Photosensitizer with high singlet oxygen quantum yield as well as preparation method and application of photosensitizer

Abstract

The invention provides a photosensitizer with high singlet oxygen quantum yield as well as a preparation method and application thereof, and belongs to the technical field of coordination chemistry and biomedicine. According to the photosensitizer with the high singlet oxygen quantum yield, two carbazole groups are specifically introduced into a phenanthroline ligand of a ruthenium complex for modification. According to the structural modification strategy, the light absorption capacity of the complex in a visible light region is remarkably enhanced, and the singlet oxygen quantum yield of the complex is improved in a breakthrough manner. In-vitro cell experiments show that the compound shows excellent phototoxicity to various tumor cell strains, has very low toxicity under dark conditions, and shows good photodynamic therapy selectivity. An in-vivo tumor-bearing mouse model experiment proves that tumor growth can be effectively inhibited under an illumination condition, and obvious systematic toxicity is not observed. The photosensitizer disclosed by the invention has the remarkable advantage of extremely high singlet oxygen quantum yield, and shows huge application potential and development value in the field of tumor photodynamic therapy.

Description

Technical Field

[0001] This invention relates to the fields of coordination chemistry and biomedical technology, and in particular to a photosensitizer with high singlet oxygen quantum yield, its preparation method, and its application. Background Technology

[0002] Photodynamic therapy (PDT) is a therapy that utilizes the interaction of light, photosensitizers, and oxygen to produce cytotoxic reactive oxygen species (such as singlet oxygen). 1 Therapeutic techniques that use oxygen (O2) to selectively kill diseased cells. The core of its clinical efficacy depends on the key performance parameters of the photosensitizer: first, it has strong absorption in the light region with good biological tissue permeability (usually referring to the near-infrared window of 600~850nm) or at least in the visible light region with stronger penetration; second, it has a high singlet oxygen quantum yield (ΦΔ) to achieve efficient treatment under limited light doses.

[0003] Currently, ruthenium(II) polypyridine complexes (such as classic systems based on 2,2'-bipyridine or 1,10-phenanthroline) are attracting widespread attention as emerging photosensitizer candidates. However, they face two interrelated and fundamental challenges in clinical translation: First, there is a contradiction between light absorption and tissue penetration. The maximum absorption wavelength (λmax) of most traditional ruthenium complexes is concentrated in the ultraviolet to blue-green light region (e.g., 450–500 nm). Although blue light centered at 470 nm has its applications in superficial treatment, this wavelength is significantly scattered and absorbed in biological tissues, resulting in limited penetration depth. This severely restricts its effective treatment of deep or large tumors. Although researchers have strived to achieve a redshift in the absorption spectrum by expanding the ligand π-conjugation system, this often comes with problems such as increased molecular structural complexity, decreased stability, or alterations in excited-state properties.

[0004] Secondly, and more critically, the low efficiency of excited-state energy utilization. Even if the photosensitizer is excited in the visible light region, the efficiency of PDT directly depends on whether the generated excited-state energy can be efficiently converted into lethal singlet oxygen. The excited states of classical Ru(II) polypyridine complexes are usually dominated by metal-ligand charge-transfer states. The efficiency of intersystem crossing to the long-lived triplet state and the efficiency of triplet energy transfer to oxygen molecules are both unsatisfactory, resulting in generally low singlet oxygen quantum yields (usually <20%). This means that most of the absorbed light energy is dissipated as heat or non-radiative energy, resulting in wasted light energy and forcing the need to increase the light or drug dose in clinical treatment, thereby potentially increasing phototoxicity to normal tissues and treatment side effects.

[0005] In summary, the current state of technology in this field is that ruthenium-based photosensitizers either have limited absorption intensity and low quantum yield in the visible light region, or struggle to achieve a significant redshift in absorption wavelength and a breakthrough improvement in quantum yield while maintaining good photostability and biocompatibility. Developing a novel photosensitizer with ultra-high singlet oxygen quantum yield at clinically relevant light wavelengths (even in the visible light region with relatively limited penetration depth) has become a highly valuable and urgent research direction for improving PDT efficiency and reducing treatment requirements. Summary of the Invention

[0006] In view of this, the purpose of this invention is to provide a high singlet oxygen quantum yield photosensitizer, its preparation method, and its application. The high singlet oxygen quantum yield photosensitizer of this invention can achieve a breakthrough improvement in singlet oxygen quantum yield, thereby compensating for its potential limitation in tissue penetration depth with extremely high photodynamic conversion efficiency, ultimately obtaining a novel antitumor photosensitizer with high efficiency and low dosage requirements.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a photosensitizer with high singlet oxygen quantum yield, having the structure shown in Formula I: Formula I, In Equation I, X is PF6 - Halogen ions, BF4 - ClO4 - or CF3SO3 - .

[0008] Preferably, the halide ion includes chloride ion (Cl... - ).

[0009] Preferably, the singlet oxygen quantum yield of the photosensitizer with high singlet oxygen quantum yield is higher than 150%.

[0010] Preferably, it has the structure shown in Formula A: Formula A.

[0011] This invention also provides a method for preparing the high singlet oxygen quantum yield photosensitizer described in the above technical solution, comprising the following steps: The ruthenium(II) complex precursor and phen-Car ligand were subjected to a coordination reaction in an organic solvent under an inert atmosphere to obtain the coordination product. The ruthenium(II) complex precursor was cis-bis(2,2'-dipyridine)ruthenium(II) dichloride hydrate. The coordination product was subjected to anion exchange to obtain the photosensitizer with high singlet oxygen quantum yield; The phen-Car ligand has the structure shown in Formula II: Formula II.

[0012] Preferably, the coordination reaction is carried out at a temperature of 45-80°C for 6-24 hours.

[0013] Preferably, the organic solvent is a mixed solvent of haloalkanes and alcohols.

[0014] This invention also provides the application of the high singlet oxygen quantum yield photosensitizer described in the above technical solution in the preparation of photodynamic therapy drugs.

[0015] Preferably, the photodynamic therapy drug is used to treat tumors.

[0016] The present invention also provides an antitumor pharmaceutical composition comprising an active ingredient and a pharmaceutically acceptable carrier or excipient, wherein the active ingredient comprises a high singlet oxygen quantum yield photosensitizer as described in the above technical solution.

[0017] This invention provides a photosensitizer with high singlet oxygen quantum yield. Instead of simply pursuing absorption wavelengths into the near-infrared region, it achieves a breakthrough increase in singlet oxygen quantum yield under clinically significant visible light irradiation through innovative molecular design. This compensates for its potential limitations in tissue penetration depth with extremely high photodynamic conversion efficiency, ultimately resulting in a novel antitumor photosensitizer with high efficiency and low dosage requirements.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: The high singlet oxygen quantum yield photosensitizer of this invention features the introduction of the phen-Car ligand, a core structural unit. The phen-Car ligand is a 1,10-phenanthroline derivative ligand modified with a carbazole group, covalently linked to two carbazole groups at specific positions (4,7-positions) of the phenanthroline core. This structural modification is key to endowing the complex with excellent properties. It significantly alters the electronic structure and excited-state properties of the complex. The carbazole group, acting as a strong electron donor and a rigid large planar group, synergistically promotes intramolecular charge transfer, enhances intersystem crossing processes, and suppresses non-radiative decay channels in the excited state. This allows it to generate singlet oxygen with extremely high efficiency after excitation in the visible light region (e.g., maximum absorption wavelength 470 nm), setting a record for singlet oxygen quantum yield. The high singlet oxygen quantum yield photosensitizer of this invention exhibits a singlet oxygen quantum yield as high as 220% under visible light (e.g., 470 nm) irradiation. This value is found in the traditional photosensitizer model compound ruthenium terpyridine (Φ). ΔThis is more than 12 times higher than that of ruthenium-based and most organic photosensitizers, representing the highest known value among publicly reported ruthenium-based photosensitizers and even most organic photosensitizers, achieving a breakthrough in photodynamic conversion efficiency. Furthermore, the photodynamic therapy effect is significant: thanks to the ultra-high singlet oxygen yield, this high singlet oxygen quantum yield photosensitizer can achieve high singlet oxygen quantum yield even at extremely low concentrations (10 μM) and low light doses (white LED lamp, 400~700 nm, 5 mW·cm⁻¹). -2 Within 30 minutes, it can produce strong phototoxicity to various human tumor cell lines (such as HeLa), with a half-inhibitory concentration (IC50) of 1,000. 50 The cytotoxicity was significantly lower than that of similar reference materials, while exhibiting very low cytotoxicity under "dark" conditions without light, demonstrating excellent light-controlled selectivity and therapeutic safety window. Simultaneously, its in vivo antitumor activity was clearly demonstrated: experiments in tumor-bearing mouse models confirmed that intratumoral injection of the complex of this invention followed by local irradiation with the corresponding wavelength significantly inhibited tumor growth, with a tumor inhibition rate far superior to the positive control group. Furthermore, no significant weight loss or systemic toxicity was observed in the mice throughout the experiment, indicating that the complex has good in vivo safety and strong therapeutic potential. Moreover, the molecular design is innovative and universal: the strategy proposed in this invention, which introduces a biscarbazole group onto the o-phenanthroline ligand, provides a novel and effective molecular design approach for designing and developing next-generation high-efficiency metal complex photosensitizers. This strategy has a clear structure-activity relationship and can be further extended to other metal center or ligand systems.

[0019] In summary, this invention has successfully prepared a novel ruthenium(II) complex photosensitizer with excellent performance. Its core advantage is "ultra-high quantum yield", which effectively solves the key bottleneck of low efficiency of existing photosensitizers and shows great clinical application value and development prospects in the field of tumor photodynamic therapy.

[0020] The present invention also provides a method for preparing the high singlet oxygen quantum yield photosensitizer described in the above technical solution. The preparation method of the present invention is simple to operate and suitable for industrial application. Attached Figure Description

[0021] Figure 1 This is a synthetic route diagram for the high singlet oxygen quantum yield photosensitizer of Example 1; Figure 2 This is a high-resolution mass spectrum of the photosensitizer with high singlet oxygen quantum yield in Example 1; Figure 3 The photosensitizer with high singlet oxygen quantum yield in Example 1 1 H NMR spectrum; Figure 4 The photosensitizer with high singlet oxygen quantum yield in Example 1 13 C NMR spectrum; Figure 5This is a high-performance liquid chromatogram of the photosensitizer with high singlet oxygen quantum yield in Example 1; Figure 6 The UV-Vis absorption spectrum of the photosensitizer with high singlet oxygen quantum yield in Example 1 is shown. Figure 7 The phosphorescence emission spectrum of the high singlet oxygen quantum yield photosensitizer in Example 1 is shown. Figure 8 The absorbance curve of the singlet oxygen generation ability of the high singlet oxygen quantum yield photosensitizer in Example 1 is shown. Figure 9 The absorbance curves show the singlet oxygen generation capacity of ruthenium terpyridine. Figure 10 This is a comparison of the kinetic curves of the singlet oxygen quantum yield photosensitizer in Example 1 and the singlet oxygen generation ability of terpyridine ruthenium; Figure 11 This is a confocal microscopy image of the high singlet oxygen quantum yield photosensitizer taken up in HeLa cells in Example 1; Figure 12 This is an evaluation diagram of the photodynamic killing effect of the high singlet oxygen quantum yield photosensitizer on tumor cells in Example 1. In this diagram, A is the survival rate curve of HeLa cells, B is the survival rate curve of EMT6 cells, and C is the staining diagram of live and dead cells in different treatment groups. Figure 13 Tumor growth in vivo in different treatment groups. Detailed Implementation

[0022] This invention provides a photosensitizer with high singlet oxygen quantum yield, having the structure shown in Formula I: Formula I, In Equation I, X is PF6 - Halogen ions, BF4 - ClO4 - or CF3SO3 - .

[0023] This invention aims to overcome the key performance deficiencies of existing metal complex photosensitizers, especially classic ruthenium(II) polypyridine complexes, in the application of photodynamic therapy for tumors. Specifically, such photosensitizers in the prior art generally suffer from the following problems: 1) Their maximum absorption wavelengths are mostly located in the ultraviolet or short-wavelength visible light regions where tissue penetration is weak, limiting their application potential in the treatment of deep tumors; 2) More importantly, their singlet oxygen quantum yields are generally low, resulting in low light energy utilization efficiency. To achieve effective treatment, high light doses or drug concentrations are often required, thereby increasing the risk of treatment side effects. This invention aims to deeply regulate the electronic structure and excited-state properties of the complex by precisely introducing two strong electron-donating, large-planar carbazole groups into the o-phenanthroline ligand. While maintaining strong visible light absorption, it promotes intramolecular charge transfer, enhances intersystem crossing efficiency, and inhibits nonradiative decay pathways, thereby increasing the singlet oxygen quantum yield to an unprecedented high level. Ultimately, it achieves a technological breakthrough of "trading efficiency for depth" or "achieving near-infrared photosensitizer efficacy in the visible light region," providing a novel solution for developing a new generation of highly efficient ruthenium-based photodynamic drugs.

[0024] This invention does not simply pursue the absorption wavelength to enter the near-infrared region, but through innovative molecular design, it achieves a breakthrough improvement in singlet oxygen quantum yield under clinically significant visible light irradiation, thereby compensating for its potential limitation in tissue penetration depth with extremely high photodynamic conversion efficiency, and ultimately obtaining a novel antitumor photosensitizer with high efficiency and low dosage requirements.

[0025] In this invention, the halogen includes chloride ions.

[0026] In this invention, the singlet oxygen quantum yield of the high singlet oxygen quantum yield photosensitizer is preferably higher than 150%, more preferably higher than 200%, and most preferably 220%.

[0027] In this invention, the high singlet oxygen quantum yield photosensitizer preferably has the structure shown in Formula A: Formula A.

[0028] This invention also provides a method for preparing the high singlet oxygen quantum yield photosensitizer described in the above technical solution, comprising the following steps: The ruthenium(II) complex precursor and phen-Car ligand were subjected to a coordination reaction in an organic solvent under an inert atmosphere to obtain the coordination product. The ruthenium(II) complex precursor was cis-bis(2,2'-dipyridine)ruthenium(II) dichloride hydrate. The coordination product was subjected to anion exchange to obtain the photosensitizer with high singlet oxygen quantum yield; The phen-Car ligand has the structure shown in Formula II: Formula II.

[0029] Unless otherwise specified, all raw materials used in this invention are commercially available products in the field.

[0030] In this invention, a ruthenium(II) complex precursor and a phen-Car ligand are subjected to a coordination reaction in an organic solvent under an inert atmosphere to obtain a coordination product. The ruthenium(II) complex precursor is cis-bis(2,2'-dipyridine)ruthenium(II) dichloride hydrate.

[0031] In this invention, the cis-bis(2,2'-dipyridine)ruthenium(II) chloride hydrate is Ru(bpy)₂Cl₂·xH₂O, CAS: 98014-14-3, and its structural formula is shown in Formula III: Formula III.

[0032] In this invention, the phen-Car ligand (4,7-bis(9H-carbazo-9-yl)-1,10-phenanthroline) has the CAS number 676542-82-8.

[0033] In this invention, the molar ratio of the ruthenium(II) complex precursor to the phen-Car ligand is preferably 1:1.

[0034] In this invention, the temperature of the coordination reaction is preferably 45~80℃, specifically 45, 50, 55, 65, 75 or 80℃, and the time is preferably 6~24h, specifically 6, 12, 18 or 24h.

[0035] In this invention, the organic solvent is preferably a mixed solvent of haloalkanes and alcohols, and the volume ratio of haloalkanes to alcohols is preferably 2:1. This invention does not have a special limitation on the amount of organic solvent used, as long as it can make the raw materials mix evenly.

[0036] In this invention, the haloalkane preferably includes dichloromethane (CH2Cl2) and / or trichloromethane, and the alcohol preferably includes methanol (MeOH) and / or ethanol.

[0037] After the coordination reaction is completed, the present invention preferably separates and purifies the reaction products sequentially to obtain the coordination product.

[0038] In this invention, the separation is preferably achieved through rotary evaporation.

[0039] In this invention, the purification is preferably carried out by first washing with methanol, then filtering to remove impurities, and obtaining a filtrate containing the coordination product.

[0040] After obtaining the coordination product, the present invention performs anion exchange on the coordination product to obtain the photosensitizer with high singlet oxygen quantum yield.

[0041] The present invention does not specifically limit the anion exchange process; any method well known to those skilled in the art can be used. In a specific embodiment of the present invention, a saturated ammonium hexafluorophosphate solution is added to the filtrate, the reaction is carried out at room temperature for 1 hour, and then the high singlet oxygen quantum yield photosensitizer is obtained by column chromatography.

[0042] This invention also provides the application of the high singlet oxygen quantum yield photosensitizer described in the above technical solution in the preparation of photodynamic therapy drugs.

[0043] In this invention, the photodynamic therapy drug is preferably used to treat tumors.

[0044] The present invention also provides an antitumor pharmaceutical composition comprising an active ingredient and a pharmaceutically acceptable carrier or excipient, wherein the active ingredient comprises a high singlet oxygen quantum yield photosensitizer as described in the above technical solution.

[0045] The present invention does not have any particular limitation on the specific types of pharmaceutically acceptable carriers or excipients, and any types well known to those skilled in the art can be used.

[0046] In this invention, the dosage form of the antitumor drug composition is preferably an injection, a lyophilized powder injection, or a nano-targeted formulation.

[0047] The present invention does not impose any particular limitation on the preparation method of the antitumor drug composition; any preparation method of the composition well known to those skilled in the art can be used.

[0048] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0049] Example 1 The principle for preparing a high singlet oxygen quantum yield photosensitizer with the structure shown in Formula A is as follows: Figure 1 As shown.

[0050] Ru(bpy)₂Cl₂·xH₂O hydrate (0.32 mmol) and the phen-Car ligand (4,7-bis(9H-carbazol-9-yl)-1,10-phenanthroline) (0.32 mmol) of Formula II were added to a CH₂Cl₂ / MeOH (2 / 1, v / v) mixed solvent and refluxed at 50 °C for 24 h under argon protection. After the reaction was completed, the mixture was rotary evaporated to dryness, methanol was added, and impurities were removed by filtration. A saturated ammonium hexafluorophosphate solution was added to the filtrate, and the mixture was reacted at room temperature for 1 h. The target product, Ru-Car, was obtained by column chromatography as 204.2 mg (0.166 mmol, 51.8%) of red solid.

[0051] The obtained photosensitizer with high singlet oxygen quantum yield was characterized in structure and its purity was determined. Structural characterization included high-resolution mass spectrometry (HPLC-MS / MS). Figure 2 ), 1 H nuclear magnetic resonance spectroscopy analysis ( Figure 3 )and 13 C nuclear magnetic resonance spectroscopy analysis ( Figure 4 Furthermore, the purity of the complex was precisely determined by high-performance liquid chromatography (HPLC). Figure 5 The results showed that its purity reached 97.57%.

[0052] Photophysical properties characterization of coordination compounds The photophysical properties of a high singlet oxygen quantum yield photosensitizer were determined. A 10 μM solution was prepared by dissolving the high singlet oxygen quantum yield photosensitizer in deionized water. The UV-Vis absorption spectrum was obtained by scanning the wavelength range of 230–600 nm using a UV-Vis spectrophotometer. Figure 6 As shown, the complex exhibits a significant metal-ligand charge transfer absorption band in the visible light region (>400 nm), indicating that it can be effectively excited by visible light. This property is beneficial for its application in photodynamic therapy.

[0053] Its room-temperature phosphorescence emission spectrum was measured using a fluorescence spectrometer: the excitation wavelength was 450 nm, and the spectrum was scanned in the range of 500–900 nm. Figure 7 The results showed that the complex exhibited a strong red phosphorescence emission peak at 650 nm, with the emission tail extending into the near-infrared region of 700–900 nm. These spectral characteristics indicate that the Ru-Car complex is suitable for deep tissue bioimaging. The effective absorption in the visible light region and the strong phosphorescence emission in the red-near-infrared region verified in this example constitute the potential photophysical basis for the application of this complex in bioimaging and photodynamic therapy.

[0054] Assessment of singlet oxygen production capacity The degradation effect of singlet oxygen on specific scavengers was detected by chemical probe method to evaluate the type II photodynamic activity of Ru-Car complexes. 9,10-Anthracenediyl-bis(methylene)dimalonic acid (ABDA) was used as the singlet oxygen scavenger, and its degradation effect on specific scavengers was assessed by chemical probe method. 1 After O2 undergoes a [4+2] cycloaddition reaction, the intensity of the characteristic ultraviolet absorption peak at 378 nm decreases accordingly, and the rate of decrease reflects the concentration of O2 in the system. 1 O2 generation. An aqueous solution containing Ru-Car (10 μM) and ABDA (100 μM) was placed in a quartz cuvette, and a white LED light source (wavelength range 400~700 nm, power density 20 mW / cm²) was used. 2 The solution was irradiated. The absorbance at 378 nm was measured using a UV-Vis spectrophotometer every 10 seconds of irradiation. The results are as follows: Figure 8 As shown, in the presence of Ru-Car, the absorption peak intensity of ABDA at 378 nm exhibits a regular and significant decrease with prolonged illumination time, indicating that ABDA is continuously consumed, confirming that Ru-Car can effectively generate singlet oxygen under visible light irradiation. Further quantitative measurements revealed that the singlet oxygen quantum yield (Φ) of this complex under white light excitation... Δ The yield can reach 220%, which is higher than that of the traditional model compound terpyridine ruthenium (Φ). Δ It is 12 times that of (≈18%), showing excellent photodynamic conversion efficiency. Figure 9 The absorbance curves show the singlet oxygen generation capacity of ruthenium terpyridine. Figure 10 A comparison of the kinetic curves of singlet oxygen generation capacity (positively correlated with quantum yield) of Ru-Car and ruthenium terpyridine.

[0055] Assay of cellular uptake behavior of Ru-Car complex Cellular uptake capacity is a crucial prerequisite for evaluating the efficacy of complexes as photosensitizers or optical probes. Confocal microscopy was used to visually examine the uptake of Ru-Car complexes in HeLa cells. The specific steps are as follows: HeLa cells were cultured at 1 × 10⁶ cells per dish. 5 Cells were seeded at a density of [number] cells / day in 35 mm confocal microscopy dishes and cultured for 24 h in DMEM medium containing 10 wt% fetal bovine serum at 37 °C and 5 vol% CO2 to allow for full cell adhesion. The original medium was discarded, and fresh complete medium containing 30 µM Ru-Car complex was added. Incubation was continued in the dark for another 4 h. After incubation, the drug-containing medium was discarded, and the cells were gently washed three times with pre-cooled PBS to thoroughly remove any untaken or adhered complexes. Immediately after washing, the cells were observed using a confocal microscope. Results are as follows: Figure 11As shown in the confocal microscopy images, significant red fluorescence signals were observed in HeLa cells incubated with Ru-Car, indicating that the Ru-Car complex could be effectively taken up by HeLa cells in a short period of time. This lays the biological basis for its intracellular singlet oxygen production or bioimaging.

[0056] Evaluation of antitumor efficacy at the in vitro cellular level: cytotoxicity and live / dead cell staining The MTS assay was used to evaluate the cytotoxicity of Ru-Car in HeLa and EMT6 cells. For the dark cytotoxicity assay of Ru-Car, cells were grown at a concentration of 1 × 10⁻⁶ cells / cells. 4 Cells were seeded at a density of 1 cell / well in 96-well plates and cultured for 24 h. Then, different concentrations (0, 0.1, 0.25, 0.5, 1, 2.5, 5, 10, 20, 30, 40, 50, 75, 125, 200 µM) of Ru-Car were added to each well in equal volumes. After 45 h of incubation, 10 µL of MTS solution (CellTiter 96 AQueous One Solution Cell Proliferation Assay) was added to each well, and incubation continued for 3 h under the same conditions. Finally, the absorbance at 500 nm was measured using a SpectraMax 190 microplate reader. For phototoxicity experiments, cells were incubated with different concentrations of Ru-Car for 4 h, and then exposed to a white LED lamp (400–700 nm, 20 mW·cm⁻¹). -2 Irradiate for 30 min, then incubate for another 41 h. Afterwards, add 10 µL of MTS solution and incubate for another 3 h. Measure the absorbance at 500 nm using a SpectraMax 190 microplate reader. Results are as follows: Figure 12 As shown in Figures A and B, Ru-Car exhibited low dark toxicity against both HeLa and EMT6 cells, with an IC50 value of [missing value]. 50 The calculated values ​​were 51.28 µM and 30.79 µM, while the IC50 value for phototoxicity was... 50 The values ​​were 0.5880µM and 0.4966µM, respectively.

[0057] To verify the photoactivated antitumor effect at the cellular level, a live / dead cell double staining assay (Ca-AM / PI) was used to visually assess cell status. Ca-AM dye stains live cells, producing green fluorescence; while PI dye stains dead cells, producing red fluorescence, allowing for direct differentiation and analysis of cell viability. Figure 12As shown in Figure C, cells treated with different methods were stained with both Ca-AM and PI. Only the Ru-Car+hv group (Ru-Car+light) showed a strong PI signal (red) and a weak Ca-AM signal (green), while the other groups (control group, hv only (light), and Ru-Car only) showed a strong Ca-AM signal (green) and a weak PI signal (red). The experimental results visually confirm that Ru-Car can kill tumor cells under light irradiation.

[0058] Evaluation of antitumor efficacy in animals at the in vivo level The in vivo therapeutic effect of Ru-Car was evaluated by constructing an EMT6-bearing breast cancer mouse model. Model construction: Sixteen female Balb / c mice (weighing 18g and 8 weeks old) were subcutaneously injected with 25µL of EMT6 cell suspension (1×10⁻⁶ cells) on the right posterior back. 6 (1 cell / each). After 7 days, tumors with a volume of approximately 100 mm were selected. 3 The mice were randomly divided into two groups of eight each for subsequent experiments.

[0059] EMT6 tumor-bearing mice were randomly divided into two groups (n=8 in each group) and received different treatments: (1) control group, (2) Ru-Car + light irradiation group. Ru-Car treatment: Ru-Car (5 mg·kg⁻¹) was injected into the tumor. -1 Light irradiation conditions: White LED light (400~700nm, power density 20mW·cm²). -2 The treatment lasted for 60 minutes. During the treatment period, the mice's body weight and tumor volume were measured every two days for a total of 14 days. The tumor volume was calculated using the formula: Volume = 0.5 × Length × Width. 2 After 14 days of treatment, the mice were euthanized, the tumors were removed, weighed, and photographed. The results were as follows... Figure 13 As shown, compared with the control group, tumor growth in mice in the Ru-Car+ light irradiation group was significantly inhibited, and some mice had complete tumor regression after treatment.

[0060] The examples fully demonstrate that the Ru-Car complex preparation method provided by the present invention is reliable and has excellent targeting, imaging, multi-mode photodynamic killing and immune activation functions, and has extremely high application value in the field of tumor photodynamic therapy.

[0061] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A photosensitizer with high singlet oxygen quantum yield, characterized in that, It has the structure shown in Equation I: Equation I, In Equation I, X is PF6 - Halogen ions, BF4 - ClO4 - or CF3SO3 - .

2. The high singlet oxygen quantum yield photosensitizer according to claim 1, characterized in that, The halide ions include chloride ions.

3. The high singlet oxygen quantum yield photosensitizer according to claim 1 or 2, characterized in that, The singlet oxygen quantum yield of the photosensitizer is higher than 150%.

4. The high singlet oxygen quantum yield photosensitizer according to claim 1, characterized in that, It has the structure shown in Equation A: Formula A.

5. The method for preparing the high singlet oxygen quantum yield photosensitizer according to any one of claims 1 to 4, characterized in that, Includes the following steps: The ruthenium(II) complex precursor and phen-Car ligand were subjected to a coordination reaction in an organic solvent under an inert atmosphere to obtain the coordination product. The ruthenium(II) complex precursor was cis-bis(2,2'-dipyridine)ruthenium(II) dichloride hydrate. The coordination product was subjected to anion exchange to obtain the photosensitizer with high singlet oxygen quantum yield; The phen-Car ligand has the structure shown in Formula II: Formula II.

6. The preparation method according to claim 5, characterized in that, The coordination reaction is carried out at a temperature of 45-80℃ for 6-24 hours.

7. The preparation method according to claim 5, characterized in that, The organic solvent is a mixture of haloalkanes and alcohols.

8. The use of the high singlet oxygen quantum yield photosensitizer according to any one of claims 1 to 4 in the preparation of photodynamic therapy drugs.

9. The application according to claim 8, characterized in that, The photodynamic therapy drug is used to treat tumors.

10. An antitumor drug composition, characterized in that, It includes an active ingredient and a pharmaceutically acceptable carrier or excipient, wherein the active ingredient includes the high singlet oxygen quantum yield photosensitizer as described in any one of claims 1 to 4.

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