Chiral iridium (III) complex photosensitizer, preparation method thereof and application of chiral iridium (III) complex photosensitizer in anti-tumor treatment

Abstract

The invention belongs to the crossing field of coordination chemistry and biomedicine, and relates to a pair of chiral iridium (III) complex photosensitizers delta-Ir-Car and lambda-Ir-Car with high singlet oxygen quantum yield, a preparation method of the chiral iridium (III) complex photosensitizers delta-Ir-Car and lambda-Ir-Car and application of the chiral iridium (III) complex photosensitizers in photodynamic therapy. Although the two enantiomers are almost the same in ultraviolet visible absorption and phosphorescence emission properties, the two enantiomers exhibit chiral dependent biological activity. Compared with the lambda-Ir-Car, the delta-Ir-Car has the advantage that the cell uptake efficiency of the delta-Ir-Car is higher. In an aqueous solution, the singlet oxygen generation capacities of the delta-Ir-Car and the delta-Ir-Car are equivalent, but at the cellular level, the delta-Ir-Car shows higher active oxygen generation capacity. More importantly, the two complexes can induce pyroptosis, and have the potential of overcoming apoptosis drug resistance and activating anti-tumor immune response. Due to the dual capabilities, the delta / lambda-Ir-Car becomes a creative drug combining photodynamic therapy and anti-tumor immunity. The preparation method disclosed by the invention is simple and convenient, high in yield and good in repeatability, and the prepared iridium complex is expected to be applied to photodynamic therapy of tumors.

Description

Technical Field

[0001] The present invention belongs to the interdisciplinary field of coordination chemistry and biomedicine, and specifically relates to a chiral iridium (III) complex photosensitizer with high singlet oxygen quantum yield, a preparation method thereof, and an application thereof in tumor photodynamic therapy. Background Art

[0002] In pharmaceutical science, the stereochemical configuration of a drug often determines its efficacy and toxicity, a phenomenon particularly evident in the thalidomide incident, where enantiomeric differences led to teratogenic effects. This enantioselectivity also extends to the field of metallodrugs, where metal coordination geometry can create a chiral environment that modulates biological activity. Despite progress in the study of chiral organic drugs, systematic exploration of chirality in transition metal complexes, especially those with potential for photodynamic therapy (PDT), remains insufficient, presenting both challenges and opportunities for rational drug design.

[0003] The core mechanism of photodynamic therapy (PDT) relies on the efficient generation of reactive oxygen species (ROS) by photosensitizers under specific wavelength light, especially singlet oxygen (1O2), which damages tumor cells or pathogens through oxidation. Δ ) is a key indicator for evaluating the performance of photosensitizers, which directly determines the therapeutic efficiency and phototoxicity threshold of PDT. Δ A value of (>0.7) can not only significantly reduce the required light dose and treatment time, but also avoid the risk of dark toxicity by reducing the amount of photosensitizer used, providing an important advantage for clinical translation. However, traditional organic photosensitizers (such as porphyrin derivatives) often suffer from problems such as insufficient intersystem crossing (ISC) efficiency, short excited state lifetime or poor photostability, resulting in 1 O2 production rate is limited. Therefore, the development of high Φ Δ New metal-based photosensitizers with controllable biodistribution have become the forefront of the PDT field.

[0004] Iridium(III) complexes are promising candidates for photodynamic therapy (PDT) due to their excellent photophysical properties, including long-lived triplet excited states, high singlet oxygen (1O2) quantum yield, and tunable redox potential. ΔHowever, it is still limited by the electronic properties of the ligand structure and the non-radiative decay of the excited state. Incorporating chirality into the design of metal photosensitizers has the potential to revolutionize precision medicine. The octahedral geometry of the iridium (III) center allows for precise stereochemical control through chiral ligand design, thereby constructing Δ / Λ-enantiomer pairs with identical photophysical properties but potentially different biological behaviors. Unlike traditional organic photosensitizers, chiral iridium (III) complexes combine stereochemical diversity with metal-centered photoredox activity, enabling the simultaneous regulation of optical properties and biological targeting.

[0005] Pyroptosis is a lytic and immunogenic form of programmed cell death characterized by the formation of gasdermin pores and the release of proinflammatory cytokines. As a key mechanism to overcome apoptosis resistance and activate anti-tumor immunity, pyroptosis has received widespread attention. Unlike apoptosis, pyroptosis triggers a strong immune response by releasing damage-associated molecular patterns (DAMPs) and interleukin-1β (IL-1β), thereby reshaping the immunosuppressive tumor microenvironment and enhancing the infiltration of immune cells. These characteristics make the induction of pyroptosis a promising strategy to combat refractory cancers, especially those that are resistant to traditional apoptosis-targeted therapies.

[0006] To improve the Φ of iridium complex photosensitizer Δ In this application, the carbazole group is introduced into the design of iridium (III) complexes. The strong electron donor property of carbazole and the extended π conjugated system can effectively adjust the energy distribution of the ligand-metal charge transfer (LMCT / MLCT) state, promote the intersystem crossing of electrons from the singlet state (S1) to the triplet state (T1), thereby maximizing 1 The quantum efficiency of the O2 generation pathway was also improved. To fully explore the therapeutic potential of chiral metallodrugs, the inventors developed a pair of carbazole-functionalized chiral iridium (III) enantiomers, Δ-Ir-Car and Λ-Ir-Car, to systematically investigate the interplay between chirality and bioactivity. By decoupling photodynamic therapy from stereochemical recognition, this invention establishes a paradigm for the development of chiral engineered metallo-photosensitizers with tailored therapeutic outcomes, bridging the gap between inorganic photochemistry and precision oncology. Summary of the Invention

[0007] The purpose of the present invention is to provide a chiral iridium (III) complex photosensitizer Δ-Ir-Car and Λ-Ir-Car with high singlet oxygen quantum yield, thereby providing a chiral photosensitizer for tumor photodynamic therapy.

[0008] The object of the present invention is achieved like this:

[0009] In the first aspect, the present invention provides a pair of chiral iridium (III) complex photosensitizers, each complex comprising two carbazole groups, wherein the chiral iridium (III) complex is respectively composed of an iridium complex cation unit represented by the following formula (I) or formula (II) and a corresponding coordinating anion:

[0010]

[0011] The coordinating anions include Cl - Br - , I - 、NO3 - or PF6 - .

[0012] As an optional manner, in the above-mentioned chiral iridium (III) complex photosensitizer, the iridium complex represented by formula (I) and the iridium complex represented by formula (II) are enantiomeric complexes with mirror symmetry, and the enantiomeric complexes have almost the same ultraviolet-visible absorption and phosphorescence emission characteristics.

[0013] The chiral iridium (III) complex photosensitizer of the present invention uses an iridium (III) complex as a core skeleton, and significantly improves its photophysical properties and singlet oxygen generation ability by introducing two carbazole groups into the o-phenanthroline ligand.

[0014] The chiral iridium (III) complex photosensitizer of the present invention has the following key characteristics: the singlet oxygen quantum yield is as high as 78%, which is about 4.3 times that of the photosensitizer [Ru(bpy)3]Cl2, and is better than most traditional photosensitizers. Although the two chiral iridium complexes show high consistency in photophysical properties, including ultraviolet absorption, phosphorescence emission, quantum yield (0.062 and 0.060, respectively), and phosphorescence lifetime (188ns and 179ns, respectively), they show significant differences in biological activity. Specifically, Δ-Ir-Car has a higher cellular uptake efficiency than Λ-Ir-Car, has a stronger ability to produce reactive oxygen species (ROS) in cells, is more likely to induce cell pyroptosis, and exhibits stronger phototoxicity. These characteristics give Δ-Ir-Car significant advantages in photodynamic therapy.

[0015] In a second aspect, the present invention further provides a method for preparing a pair of chiral iridium (III) complex photosensitizers according to the first aspect, the preparation method comprising the following steps:

[0016] (1) Synthesis of chiral iridium intermediate Λ-Ir-L pro or Δ-Ir-D pro ;

[0017] (2) synthesizing enantiomerically pure iridium complexes ΔΔ-Ir1 or ΛΛ-Ir1 by removing the auxiliary ligand;

[0018] (3) By reacting with a carbazole functionalized ligand, the target chiral iridium complex Λ-Ir-Car shown in formula (I) or Δ-Ir-Car shown in formula (II) is finally synthesized.

[0019] As an optional method, in the above preparation method, chiral D- or L-proline is reacted with the iridium complex precursor rac-[Ir(ppy)2(μ-Cl)]2 to generate the corresponding chiral iridium complex precursor Λ-Ir-L pro or Δ-Ir-D pro .

[0020] As an optional method, in the above preparation method, the chiral iridium complex precursor Λ-Ir-L synthesized in step (1) pro or Δ-Ir-D pro By reacting with concentrated hydrochloric acid in methanol solution, ΔΔ-Ir1 or ΛΛ-Ir1 with a clear chiral configuration can be efficiently synthesized.

[0021] As an optional manner, in the above preparation method, in step (2), the obtained ΔΔ-Ir1 or ΛΛ-Ir1 is reacted with a phenanthroline ligand containing a carbazole group to synthesize the target chiral iridium complex Λ-Ir-Car or Δ-Ir-Car.

[0022] The present invention has carried out a comprehensive structural characterization of the synthesized chiral iridium (III) complex photosensitizer (Δ / Λ-Ir-Car), including high-resolution mass spectrometry, 1H nuclear magnetic resonance spectroscopy and 13 C nuclear magnetic resonance spectrum analysis. In addition, the purity of the complex was accurately determined by high performance liquid chromatography (HPLC), and the results showed that its purity reached more than 99%.

[0023] This study systematically investigated the photophysical properties of chiral iridium (III) complex photosensitizers, including UV-visible absorption spectroscopy, phosphorescence emission spectroscopy, phosphorescence lifetime measurements, and circular dichroism analysis. UV-visible absorption spectroscopy analyzed the absorption characteristics, phosphorescence emission spectroscopy revealed the luminescence behavior, phosphorescence lifetime measurements assessed the excited-state lifetime, and circular dichroism spectroscopy verified the enantiomeric relationship. These studies provided comprehensive characterization data for the complex's photophysical properties.

[0024] This study evaluated the singlet oxygen generation capacity of a chiral iridium (III) complex photosensitizer, specifically examining its singlet oxygen generation capacity in aqueous solution under white light irradiation. Experimental verification demonstrated that the complex exhibited excellent singlet oxygen generation efficiency (78%) in aqueous solution, providing important evidence for photodynamic therapy.

[0025] The present invention conducted cellular endocytosis experiments on the prepared chiral iridium (III) complex photosensitizers, systematically evaluating the cellular uptake efficiency of the two chiral iridium complexes. The experimental results showed that Δ-Ir-Car exhibited higher cellular uptake efficiency than Λ-Ir-Car, providing important experimental evidence for subsequent biological activity studies.

[0026] The present invention tested the intracellular reactive oxygen species (ROS) levels of the chiral iridium (III) complex photosensitizers prepared in this study, systematically evaluating the ROS production efficiency of the two chiral iridium complexes within cells. The experimental results showed that Δ-Ir-Car exhibited a stronger ROS production capacity than Λ-Ir-Car within cells, a property that is of great significance for photodynamic therapy.

[0027] The chiral iridium (III) complex photosensitizer prepared in this study was thoroughly investigated using Western blot experiments, verifying the cleavage of caspase-3 and the activation of GSDME by shear. The results showed that Δ-Ir-Car exhibited a stronger ability to induce pyroptosis than Δ-Ir-Car, further confirming its potential in photodynamic therapy.

[0028] In a third aspect, the present invention provides the use of the chiral iridium (III) complex photosensitizer described in the first aspect or the chiral iridium (III) complex photosensitizer prepared by the preparation method described in the second aspect in the preparation of drugs for tumor photodynamic therapy.

[0029] The chiral iridium (III) complex photosensitizer of the present invention has the following advantages and beneficial effects:

[0030] (1) High singlet oxygen quantum yield: The chiral iridium (III) complex of the present invention has a singlet oxygen quantum yield of up to 78%, which is about 4.3 times that of the traditional photosensitizer [Ru(bpy)3]Cl2, significantly better than most traditional photosensitizers, thereby providing stronger reactive oxygen generation ability in photodynamic therapy.

[0031] (2) Excellent photophysical properties: The two chiral iridium complexes exhibit highly consistent photophysical properties, including ultraviolet absorption, phosphorescence emission, quantum yield (0.062 and 0.060, respectively), and phosphorescence lifetime (188 ns and 179 ns, respectively), ensuring their stability and reliability in photodynamic therapy.

[0032] (3) Significant differences in bioactivity: Although the two chiral iridium complexes are almost identical in photophysical properties, they exhibit significant differences in bioactivity. Δ-Ir-Car is superior to Λ-Ir-Car in terms of cellular uptake efficiency, reactive oxygen species production capacity, cell pyroptosis induction, and phototoxicity, providing higher therapeutic efficiency and selectivity for photodynamic therapy.

[0033] (4) Cell pyroptosis induction ability: Both chiral iridium complexes can effectively induce cell pyroptosis, overcome apoptosis resistance through the Caspase-3 / GSDME pathway, and activate anti-tumor immune responses, providing a new strategy for the treatment of refractory cancers.

[0034] (5) Chirality-regulated bioactivity: By introducing chirality, the present invention achieves the decoupling of photophysical properties and bioactivity, providing new ideas for precision medicine and chiral drug design.

[0035] (6) Simple preparation method: The preparation method of the present invention is simple, has high yield and good reproducibility, and is suitable for large-scale production and application.

[0036] In summary, the chiral iridium (III) complex photosensitizer of the present invention exhibits excellent performance and potential in photodynamic therapy, providing an innovative solution to overcome the limitations of traditional photosensitizers. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 The synthetic route of the chiral iridium (III) complex photosensitizer of the present invention is as follows;

[0038] Figure 2 The figure is a structural characterization and purity identification diagram of the chiral iridium (III) complex photosensitizer of the present invention;

[0039] Figure 3 Graph showing the photophysical properties of the chiral iridium (III) complex photosensitizer of the present invention;

[0040] Figure 4 Graph showing the singlet oxygen generation capability of the chiral iridium (III) complex photosensitizer of the present invention;

[0041] Figure 5 1 is a graph showing the cellular uptake efficiency of the chiral iridium (III) complex photosensitizer of the present invention;

[0042] Figure 6 Graph showing the intracellular reactive oxygen species generation capability of the chiral iridium (III) complex photosensitizer of the present invention;

[0043] Figure 7 The phototoxicity and dark toxicity diagrams of the chiral iridium (III) complex photosensitizer of the present invention are shown;

[0044] Figure 8 This is a Western blot image of cell pyroptosis induced by the chiral iridium (III) complex photosensitizer of the present invention. DETAILED DESCRIPTION

[0045] The present invention will be further described below with reference to specific embodiments. It should be understood that the specific embodiments described herein are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0046] If no specific techniques or conditions are specified in the examples, the experiments were carried out according to the techniques or conditions described in the literature in the field or according to the product instructions. If no manufacturer is specified for the reagents or instruments used, they are all conventional products that can be purchased through regular channels.

[0047] The experimental methods in the following examples are conventional methods unless otherwise specified. The experimental materials used in the following examples are commercially available products unless otherwise specified.

[0048] Example 1

[0049] Preparation of chiral iridium (III) complex photosensitizer, the synthesis steps are as follows Figure 1 shown.

[0050] (1) Chiral iridium intermediate (Λ-Ir-L pro or Δ-Ir-D pro Preparation of ) : rac-[Ir(ppy)2(μ-Cl)]2 (322 mg, 0.3 mmol) and D- or L-proline (86 mg, 0.75 mmol) were refluxed in a dichloromethane mixture containing sodium methoxide (49 mg, 0.9 mmol) for 2 hours. After the reaction, the solvent was removed and the residue was dissolved in 30 mL of dichloromethane and then washed with H2O (3×10 mL) to remove unreacted proline. The combined organic layers were concentrated under high vacuum. Purification by silica gel column chromatography (200-300 mesh, eluent: dichloromethane / methanol = 100:1→10:1, v / v) gave yellow solid Δ-Ir-D pro (222 mg, yield 60.3%) or Λ-Ir-L pro (290 mg, 78.7% yield).

[0051] (2) Preparation of enantiomerically pure iridium complex (ΔΔ-Ir1 or ΛΛ-Ir1): pro or Λ-Ir-L pro100 mg of each was dissolved in CH3OH, followed by the addition of 1 M HCl solution (1 mL). The mixture was stirred until the reaction was complete. The solvent was filtered off, and the precipitate was washed with CH3OH and petroleum ether, followed by drying to obtain a yellow solid product. The specific yields were as follows: 75 mg (85.8%) for ΔΔ-Ir1 and 63 mg (72%) for ΔΔ-Ir1.

[0052] (3) Preparation of the target chiral iridium complex (Λ-Ir-Car or Δ-Ir-Car): ΛΛ-Ir1 or ΔΔ-Ir1 (70 / 58.8 μmol, 75 / 63 mg) was mixed with 4,7-di(9H-carbazol-9-yl)-1,10-phenanthroline (154 / 129.3 μmol, 78.58 / 66.01 mg, 2.2 equivalents) and dissolved in a mixed solvent of dichloromethane and methanol (1:1, 20 mL). The mixture was stirred at 50°C overnight. Subsequently, 1 equivalent of ammonium hexafluorophosphate was added and stirring was continued for 1 hour. After the solvent was removed under reduced pressure, the product was purified by silica gel column chromatography (200-300 mesh, eluent: dichloromethane / methanol = 100:1→10:1, v / v). The purified orange-red solid was dissolved in a small amount of dichloromethane (2-3 mL) and slowly added dropwise to petroleum ether (20 mL). The mixture was allowed to settle. The precipitate was filtered and dried to obtain a red solid, Δ-Ir-Car (111 mg, 81.7% yield) or Δ-Ir-Car (143 mg, 88.6% yield).

[0053] The obtained Λ-Ir-Car and Δ-Ir-Car were structurally characterized and their purity was determined. Since Λ-Ir-Car and Δ-Ir-Car have almost identical spectra, only the high-resolution mass spectrum of Δ-Ir-Car is shown here ( Figure 2 A and Figure 2 B) 1 H NMR spectroscopy ( Figure 2 C) and 13 C NMR spectroscopy analysis ( Figure 2 D). In addition, the purity of the complex was accurately determined by high performance liquid chromatography (HPLC), and the results showed that its purity reached more than 99% ( Figure 2 E).

[0054] Example 2

[0055] The photophysical properties of chiral iridium (III) complex enantiomers were studied, including UV-visible absorption spectroscopy, phosphorescence emission spectroscopy, phosphorescence lifetime determination, and circular dichroism analysis.

[0056] (1) UV-visible absorption spectrum. Dissolve the chiral iridium (III) complex in deionized water to prepare a sample of a certain concentration (usually 10-50 μM). Inject the sample solution into a cuvette and use a UV-visible spectrophotometer with a scanning range of 230-600 nm and a suitable slit width and scanning speed. Perform spectral scanning and record the absorption spectrum. The results are as follows: Figure 3 The results show that Λ-Ir-Car and Δ-Ir-Car have almost identical UV-visible absorption spectra. It is worth noting that in the range of 350-500nm, there is 1 The characteristic absorption band of MLCT indicates that the complex can be excited by visible light, which is particularly beneficial for photodynamic therapy.

[0057] (2) Phosphorescence emission spectrum. Similarly, the chiral iridium (III) complex is dissolved in an appropriate solvent to prepare a solution of a certain concentration. Using a fluorescence spectrometer, set the excitation wavelength to 405nm and the emission wavelength scanning range to 500-900nm. Measure the phosphorescence emission spectrum at room temperature and record the emission spectrum. The results are as follows: Figure 3 As shown in Figure B, the results show that Λ-Ir-Car and Δ-Ir-Car have almost identical fluorescence emission spectra. The maximum emission peak is located at 625 nm. Notably, the tail peak of the complex emission lies in the near-infrared region within the 700-900 nm range, which is particularly advantageous for deep tissue bioimaging.

[0058] (3) Phosphorescence lifetime measurement. Dissolve the chiral iridium (III) complex in an appropriate solvent to prepare a solution of a certain concentration. Inject the sample solution into a cuvette and use a time-resolved spectrometer to measure the phosphorescence lifetime and record the phosphorescence decay curve. By fitting the phosphorescence decay curve, calculate the phosphorescence lifetime and evaluate the excited state lifetime of the complex. The results are as follows: Figure 3 C. The results show that the phosphorescence lifetimes of Λ-Ir-Car and Δ-Ir-Car are 179 and 188 nanoseconds, respectively.

[0059] (4) Circular dichroism analysis. Dissolve the chiral iridium (III) complex in an appropriate solvent to prepare a solution of a certain concentration. Use a circular dichroism spectrometer, set the scanning range to 250-500nm, and select a suitable slit width and scanning speed. Inject the sample solution into a cuvette, ensuring that the light-transmitting surface of the cuvette is clean and free of contamination. Measure the circular dichroism spectrum and record the circular dichroism spectrum. The results are as follows: Figure 3 D. The results show that Λ-Ir-Car and Δ-Ir-Car have mirror-symmetric circular dichroism spectra.

[0060] These testing steps and analytical methods can comprehensively characterize the photophysical properties of chiral iridium (III) complex photosensitizers, providing important basic data for subsequent biological activity research and applications.

[0061] Example 3

[0062] Evaluation of the singlet oxygen generation ability of chiral iridium (III) complex photosensitizers. Using 9,10-anthracenediyl-bis(methylene)dimalonic acid (ABDA) as a singlet oxygen probe and [Ru(bpy)3]Cl2 as a reference, a white LED lamp was used as the light source to illuminate a mixed solution of the photosensitizer and ABDA. The absorbance change of ABDA at 378 nm was recorded by a UV-visible spectrophotometer to evaluate the singlet oxygen generation ability of chiral iridium (III) complex photosensitizers (Λ-Ir-Car and Δ-Ir-Car) in aqueous solution. 1 O2) ability. The results are as follows Figure 4 A- Figure 4 D. The results show that Λ-Ir-Car and Δ-Ir-Car react faster with ABDA than [Ru(bpy)₃]Cl₂. The calculated singlet oxygen quantum yields of Λ-Ir-Car and Δ-Ir-Car reach 78%, far exceeding that of most photosensitizers and 4.3 times that of [Ru(bpy)₃].

[0063] Example 4

[0064] Evaluation of the cellular uptake efficiency of chiral iridium (III) complex photosensitizers. To evaluate the uptake efficiency of chiral iridium (III) complex photosensitizers (Λ-Ir-Car and Δ-Ir-Car) in HeLa cells and compare the differences in cellular uptake between the two enantiomers, solutions of Λ-Ir-Car and Δ-Ir-Car at different concentrations (5 μM, 15 μM, and 30 μM) were added to HeLa cell culture dishes and incubated in a 37°C, 5% CO2 incubator for 4 hours. After incubation, the cells were gently washed three times with PBS buffer to remove unabsorbed complexes. The phosphorescence signals of the complexes within the cells were observed using confocal microscopy to evaluate the cellular uptake efficiency of Λ-Ir-Car and Δ-Ir-Car.

[0065] The results are as follows Figure 5 A- Figure 5 The experimental results show that, at the same concentration, Δ-Ir-Car exhibits significantly higher uptake efficiency in HeLa cells than Δ-Ir-Car. For example, at a concentration of 30 μM, the average fluorescence intensity of Δ-Ir-Car is twice that of Δ-Ir-Car, indicating that Δ-Ir-Car is more readily taken up by cells. The average fluorescence intensity of the intracellular complex was measured using phosphorescence images recorded using a confocal microscope.

[0066] Example 5

[0067] Evaluation of the intracellular reactive oxygen species (ROS) generation ability of chiral iridium (III) complex photosensitizers. To evaluate the ability of chiral iridium (III) complex photosensitizers (Λ-Ir-Car and Δ-Ir-Car) to generate reactive oxygen species (ROS) in HeLa cells, 15 μM Λ-Ir-Car and Δ-Ir-Car were added to HeLa cell culture dishes and incubated in a 37°C, 5% CO2 incubator for 4 hours. After incubation, 10 μM DCFH-DA solution was added and incubated for another 30 minutes to allow the probe to enter the cells and convert to DCF. A confocal microscope with a 405 nm laser was used as the light source, with appropriate excitation and emission wavelengths set. An image was captured every 1 minute of irradiation, and the cycle was repeated 6 times to record changes in DCF fluorescence intensity within the cells.

[0068] The results are as follows Figure 6 The experimental results showed that under 405nm laser irradiation, Δ-Ir-Car exhibited a stronger ability to generate reactive oxygen species in HeLa cells than Λ-Ir-Car. Under the same experimental conditions, the green fluorescence intensity in cells treated with Δ-Ir-Car and light was significantly higher than that in cells treated with Λ-Ir-Car and light, indicating that Δ-Ir-Car generated more reactive oxygen species in the cells.

[0069] Example 6

[0070] Evaluation of the tumor cell killing ability of chiral iridium (III) complex photosensitizers. The cytotoxicity of chiral iridium (III) complex photosensitizers (Λ-Ir-Car and Δ-Ir-Car) under light and dark conditions was evaluated by the MTS method, and their phototoxicity and dark toxicity were compared. HeLa cells were seeded in 96-well plates, with approximately 5,000 cells per well, and cultured in a 37°C, 5% CO2 incubator for 24 hours to allow the cells to adhere to the wall and grow. Different concentrations of Λ-Ir-Car and Δ-Ir-Car solutions were added to 96-well plates, with 5 replicate wells in each group. The cells in the experimental group were treated with light (white light LED, 20 mW cm -2 , 20 minutes), and the control group cells were kept in the dark. After the incubation was completed, MTS reagent was added and incubated for another 3 hours. The absorbance was measured at 550 nm using a microplate reader and the data were recorded. The cell survival rate of each group was calculated, and the cytotoxicity of Δ-Ir-Car and Δ-Ir-Car under light and dark conditions was compared.

[0071] The results are as follows Figure 7As shown. The dark toxicity of Λ-Ir-Car and Δ-Ir-Car were 134.1μM and 143.1μM, respectively. The phototoxicity was 0.046μM and 0.189μM, respectively. Both Λ-Ir-Car and Δ-Ir-Car showed significant phototoxicity under light conditions, while the dark toxicity was lower. The phototoxicity of Δ-Ir-Car at the same concentration was significantly higher than that of Λ-Ir-Car, indicating that it has a higher tumor cell killing ability in photodynamic therapy.

[0072] Example 7

[0073] Evaluation of the ability of chiral iridium (III) complex photosensitizers to induce cell pyroptosis. Western blot experiments were performed to verify the ability of chiral iridium (III) complex photosensitizers (Λ-Ir-Car and Δ-Ir-Car) to induce cell pyroptosis, especially the cleavage of Caspase-3 and the activation of GSDME. HeLa cells were seeded in culture dishes and placed in a 37°C, 5% CO2 incubator to adhere overnight. 15 μM Λ-Ir-Car or Δ-Ir-Car solution was added to the experimental group and the experimental group cells were illuminated (white light LED, 20 mW cm -2 , 10 minutes), and the control group cells were kept in the dark. The cells were gently washed with PBS buffer and lysis buffer was added to extract total protein. The protein samples were subjected to SDS-PAGE electrophoresis to separate the proteins. The proteins were transferred to a PVDF membrane. The membrane was incubated with primary antibodies (anti-Caspase-3, anti-GSDME) and then incubated with secondary antibodies. Protein bands were detected using a chemiluminescence imaging system. Western blot results were analyzed to observe the cleavage of Caspase-3 and GSDME.

[0074] The results are as follows Figure 8 As shown. Experimental results showed that Δ-Ir-Car exhibited a stronger ability to induce cell pyroptosis than Λ-Ir-Car. Western blot results showed that the cleavage levels of Caspase-3 and GSDME in cells treated with Δ-Ir-Car were significantly higher than those in cells treated with Λ-Ir-Car, indicating that Δ-Ir-Car more effectively activated the pyroptosis pathway. This chirality-dependent pyroptosis-inducing ability provides a new research direction for the application of chiral iridium (III) complexes in photodynamic therapy.

[0075] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A pair of chiral iridium (III) complex photosensitizers, characterized in that Each complex contains two carbazole groups, and the chiral iridium (III) complex is composed of an iridium complex cation unit represented by the following formula (I) or formula (II) and a corresponding coordinating anion: The coordinating anions include Cl - Br - , I - 、NO3 - or PF6 - .

2. The chiral iridium (III) complex photosensitizer according to claim 1, characterized in that The iridium complex represented by formula (I) and the iridium complex represented by formula (II) are enantiomeric complexes with mirror symmetry. The enantiomeric complexes have almost the same ultraviolet-visible absorption and phosphorescence emission characteristics.

3. The method for preparing the chiral iridium (III) complex photosensitizer according to claim 1 or claim 2, characterized in that: The following steps are involved: (1) Synthesis of chiral iridium intermediate Λ-Ir-L pro or Δ-Ir-D pro ; (2) synthesizing enantiomerically pure iridium complexes ΔΔ-Ir1 or ΛΛ-Ir1 by removing the auxiliary ligand; (3) By reacting with a carbazole functionalized ligand, the target chiral iridium complex Λ-Ir-Car shown in formula (I) or Δ-Ir-Car shown in formula (II) is finally synthesized.

4. The preparation method according to claim 3, characterized in that The chiral D- or L-proline reacts with the iridium complex precursor rac-[Ir(ppy)2(μ-Cl)]2 to generate the corresponding chiral iridium complex precursor Λ-Ir-L pro or Δ-Ir-D pro .

5. The preparation method according to claim 3, characterized in that The chiral iridium complex precursor Λ-Ir-L synthesized in step (1) pro or Δ-Ir-D pro By reacting with concentrated hydrochloric acid in methanol solution, ΔΔ-Ir1 or ΛΛ-Ir1 with a clear chiral configuration can be efficiently synthesized.

6. The preparation method according to claim 3, characterized in that In step (2), the obtained ΔΔ-Ir1 or ΛΛ-Ir1 is reacted with a phenanthroline ligand containing a carbazole group to synthesize the target chiral iridium complex Λ-Ir-Car or Δ-Ir-Car.

7. The chiral iridium (III) complex photosensitizer according to claim 1 or claim 2, characterized in that The enantiomeric complex has a high singlet oxygen quantum yield of up to 78%, which is better than most photosensitizers, and there is no significant difference in the singlet oxygen quantum yield of the two in aqueous solution. In cells, Δ-Ir-Car has a significantly higher reactive oxygen species production ability than Λ-Ir-Car.

8. The chiral iridium (III) complex photosensitizer according to claim 1 or claim 2, characterized in that The enantiomeric complexes showed significant differences in cellular uptake efficiency. Under the same experimental conditions, Δ-Ir-Car exhibited higher cellular uptake efficiency than Λ-Ir-Car.

9. The chiral iridium (III) complex photosensitizer according to claim 1 or claim 2, characterized in that The enantiomeric complexes can effectively induce cell pyroptosis, showing the potential to overcome apoptosis resistance and activate anti-tumor immune responses.

10. Use of the chiral iridium (III) complex photosensitizer according to claim 1 or claim 2, or the chiral iridium (III) complex photosensitizer prepared by the preparation method according to any one of claims 3 to 6, in the preparation of a drug for tumor photodynamic therapy.

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