Aggregation-induced emission charge type free radical photosensitizer as well as preparation method and antibacterial application thereof

Abstract

The invention discloses an aggregation-induced emission charge type free radical photosensitizer as well as a preparation method and antibacterial application thereof, and belongs to the technical field of photosensitizers and antibacterial materials. A motion type electron donor is introduced into a molecular structure of the photosensitizer, a relatively strong charge transfer (CT) state is constructed, and meanwhile, an intermolecular pi-pi accumulation effect of molecules in an aggregation state is inhibited, so that a material is endowed with a remarkable aggregation fluorescence enhancement characteristic. An electron acceptor is introduced into the molecular structure, so that the CT state of the product is enhanced. Besides, due to the relatively strong distortion degree between the electron donor and the electron acceptor, separation of the highest occupied orbital and the lowest unoccupied orbital of molecules is facilitated, so that a relatively small singlet-triplet state energy level difference is realized, and excitation of singlet state energy gap crossing to the triplet state is promoted to realize efficient ROS generation. Meanwhile, due to the fact that molecular aggregation movement is limited, non-radiation excitation energy is effectively inhibited, energy is promoted to be dissipated in a radiation transition way, and the fluorescence efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of photosensitizers and antibacterial materials, and in particular relates to an aggregation-induced luminescence charge-type free radical photosensitizer, a preparation method thereof and antibacterial application thereof. Background Art

[0002] Fluorescence imaging-guided photodynamic therapy (PDT) has received continuous attention in the treatment of clinical diseases due to its outstanding therapeutic advantages such as non-invasiveness, low drug resistance, real-time treatment visualization and good spatiotemporal selectivity. As one of the important components in the PDT process, the development of efficient and multifunctional photosensitizers has become an important research direction. The molecular structure of commercial photosensitizers (such as porphyrin, methylene blue and Bengal rose red derivatives) has the characteristics of planar rigidity. Although they have good ROS efficiency, high molar absorption coefficient and low cytotoxicity, the rigid molecular structure will also induce intermolecular π-π stacking, which is easy to aggregate in the physiological environment, causing fluorescence quenching and ROS efficiency reduction, which seriously affects the effect of clinical disease diagnosis and treatment. Charge-type photosensitizers have received increasing attention in the field of photodynamic therapy (PDT) because of their good targeting to mitochondria and Gram-positive bacteria and the advantages of producing highly efficient reactive oxygen species (ROS). However, charge-type photosensitizers have strong intramolecular charge transfer and intermolecular dipole-dipole interactions, which are still prone to cause fluorescence quenching and ROS efficiency reduction of photosensitizers. In addition, most commercial photosensitizers produce singlet oxygen and have severe oxygen dependence, which makes it difficult for photosensitizers to continuously and efficiently produce ROS in an oxygen-deficient environment. Therefore, the development of a new photosensitizer material system with enhanced aggregation fluorescence efficiency and ROS efficiency and low oxygen dependence is of great research significance for clinical tumor treatment and antibacterial.

[0003] Aggregation-induced emission photosensitizers have the unique advantage of enhancing fluorescence efficiency and ROS efficiency through aggregation, and are expected to replace traditional commercial photosensitizers and promote the development of medical fields such as photodynamic anticancer and antibacterial. However, existing aggregation-induced emission photosensitizers still have the problem of being unable to continuously and efficiently produce ROS in a hypoxic environment.

[0004] Therefore, a photosensitizer with low oxygen dependence and high aggregation-induced fluorescence efficiency and ROS efficiency is urgently needed to solve the above problems. Summary of the invention

[0005] In order to solve the above technical problems, the present invention proposes a class of aggregation-induced luminescence charge-type free radical photosensitizers and their preparation method and antibacterial application.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides a type of aggregation-induced luminescence charge-type free radical photosensitizer, the general structural formula of which is:

[0008]

[0009] In the formula, R1 is hydrogen or an aromatic condensed ring, R2 is benzothiadiazole, a benzothiadiazole derivative or a carbon-carbon double bond, R3 is an alkyl group, and X- is an anion pair.

[0010] The present invention introduces a mobile electron donor into the molecular structure of the photosensitizer, constructs a strong charge transfer (CT) state, and suppresses the intermolecular π-π stacking effect of the molecule in the aggregated state, thereby giving the material a significant aggregation fluorescence enhancement characteristic. And introduce an electron acceptor into the molecular structure, thereby strengthening the CT state of the product. In addition, due to the strong degree of distortion between the electron donor-acceptor, it is beneficial to separate the highest occupied orbital (HOMO) and the lowest unoccupied orbital (LUMO) of the molecule, thereby achieving a smaller singlet-triplet energy level difference (ΔEst), promoting the excited singlet energy gap crossing (ISC) to the triplet state to achieve efficient ROS generation. At the same time, due to the limited molecular aggregation motion, the non-radiative excitation energy is effectively suppressed, which promotes the energy to dissipate energy in the radiation transition pathway, and the fluorescence efficiency is increased.

[0011] The aggregation-induced luminescence charged free radical photosensitizer provided by the present invention has high fluorescence quantum efficiency and ROS generation ability, and has good application prospects in the field of Gram-positive bacteria-specific fluorescence recognition and photodynamic antibacterial.

[0012] Preferably, the aromatic fused ring is one of (a)-(d); the structural formula of (a)-(d) is as follows:

[0013]

[0014] Among them, "*" represents the site of connection with the mother nucleus.

[0015] Furthermore, the R1 is a pyrene-condensed ring (d).

[0016] Furthermore, the R2 is benzothiadiazole.

[0017] Preferably, R3 is any one of alkyl groups with a carbon chain number ≤ 18.

[0018] Preferably, R3 is one of methyl, ethyl, propyl, butyl, isobutyl, tert-butyl and hexyl; more preferably, it is methyl.

[0019] Preferably, the X - It is one of iodide ion, bromide ion, hydroxide ion, tetrafluoroborate ion, nitrate ion, sulfate ion and hexafluorophosphate ion.

[0020] Furthermore, the X - It is iodide ion.

[0021] The present invention provides a method for preparing an aggregation-induced luminescence charge-type free radical photosensitizer according to the above technical scheme, comprising the following steps: using a triphenylamine derivative and 1-pyreneboronic acid or 4,7-dibromo-5,6-difluoro-benzothiadiazole, a triphenylamine derivative and 4-formylphenylboronic acid as raw materials, obtaining an intermediate product through a Suzuki coupling reaction; subjecting the obtained intermediate product and a charge-type pyridine derivative to an Aldol dehydration condensation reaction under the action of a catalyst, thereby obtaining the aggregation-induced luminescence charge-type free radical photosensitizer.

[0022] Preferably, the molar ratio of the triphenylamine derivative to 1-pyreneboronic acid is 2:5; the molar ratio of 4,7-dibromo-5,6-difluoro-benzothiadiazole, the triphenylamine derivative and 4-formylphenylboronic acid is 5:6:3.

[0023] Furthermore, the triphenylamine derivative includes 4-[N,N-bis(4-bromophenyl)amino]benzaldehyde or triphenylamine boric acid.

[0024] Furthermore, the charged pyridine derivative includes 1,4-dimethylpyridinium-1-iodide.

[0025] Furthermore, the molar ratio of the intermediate product to the charged pyridine derivative is 5:7.

[0026] Furthermore, the catalyst is piperidine; the usage ratio of the piperidine to the charged pyridine derivative is 10 μL:0.7 mmol.

[0027] Preferably, the reaction time of the Suzuki coupling reaction and the Aldol dehydration condensation reaction is 12 h.

[0028] The present invention provides the use of the aggregation-induced luminescence charge-type free radical photosensitizer described in the above technical solution in the preparation of a drug for specific fluorescence recognition of Gram-positive bacteria.

[0029] The present invention provides the application of the aggregation-induced luminescence charge-type free radical photosensitizer described in the above technical solution in the field of preparing photodynamic antibacterial drugs.

[0030] Compared with the prior art, the present invention has the following advantages and technical effects:

[0031] (1) The aggregation-induced emission charge-type free radical photosensitizer provided by the present invention overcomes the aggregation fluorescence quenching effect and the problem of decreased ROS efficiency due to aggregation existing in existing commercial photosensitizers.

[0032] (2) The synthesis method of the aggregation-induced emission charge-type free radical photosensitizer provided by the present invention is simple, the raw materials are easily available, the yield is high, and the obtained material structure is stable.

[0033] (3) The aggregation-induced luminescence charge-type free radical photosensitizer provided by the present invention has a specific fluorescence recognition effect on Gram-positive bacteria.

[0034] (4) The aggregation-induced luminescence charge-type free radical photosensitizer provided by the present invention has good photodynamic antibacterial effect on Escherichia coli, Staphylococcus aureus and methicillin-resistant Staphylococcus aureus. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0036] Figure 1 The ultraviolet absorption spectrum and fluorescence spectrum of the photosensitizer prepared in Example 1-2 in dichloromethane solvent;

[0037] Figure 2 The fluorescence emission spectra of the photosensitizer prepared in Example 1-2 in a dimethyl sulfoxide / toluene mixed solvent as the toluene content increases;

[0038] Figure 3 The performance of the photosensitizer prepared in Example 1-2 in generating ROS under white light irradiation conditions;

[0039] Figure 4 The performance of the photosensitizer prepared in Example 1-2 in generating singlet oxygen under white light irradiation conditions;

[0040] Figure 5 The photosensitizer prepared in Example 1-2 has the ability to generate superoxide anion radical active oxygen under white light irradiation conditions;

[0041] Figure 6 The performance of the photosensitizer prepared in Example 1-2 in generating hydroxyl radical active oxygen under white light irradiation conditions;

[0042] Figure 7 This is a diagram showing the fluorescence staining effect of pTPAPy prepared in Example 1 on Escherichia coli;

[0043] Figure 8 This is a diagram showing the fluorescence staining effect of pTPAPy prepared in Example 1 on Staphylococcus aureus;

[0044] Fig. 9 This is a fluorescence staining effect diagram of pTPAPy prepared in Example 1 on methicillin-resistant Staphylococcus aureus;

[0045] Fig.10 The photodynamic antibacterial effect of different concentrations of pTPAPy on Escherichia coli;

[0046] Fig.11 The photodynamic antibacterial effect of different concentrations of pTPAPy on Staphylococcus aureus;

[0047] Fig.12 The photodynamic antibacterial effect of different concentrations of pTPAPy on methicillin-resistant Staphylococcus aureus. DETAILED DESCRIPTION

[0048] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0050] The room temperature in the embodiments of the present invention refers to "25±2°C".

[0051] Unless otherwise specified, the raw materials in the examples of the present invention were purchased from commercial sources.

[0052] Example 1

[0053] An aggregation-induced luminescence charge-type free radical photosensitizer, the structural formula of which is:

[0054]

[0055] The synthetic route is:

[0056]

[0057] The specific preparation process is:

[0058] (1) Preparation of pTPA-CHO

[0059] 4-[N,N-bis(4-bromophenyl)amino]benzaldehyde (858mg, 2mmol) and 1-pyreneboric acid (1.23g, 5mmol) and tetrakistriphenylphosphine palladium (Pd(PPh3)4, 46mg) were placed in a two-necked flask and filled with N2. Under the protection of N2, tetrahydrofuran (THF, 20mL) and K2CO3 aqueous solution (2M, 8mL) were injected into the reaction vessel and refluxed for 12h. After the reaction was completed, the reaction solution was extracted three times with dichloromethane (DCM) and column chromatography was performed to obtain yellow powder pTPA-CHO (734mg).

[0060] The characterization data of the obtained pTPA-CHO are: 1 H NMR (400MHz, d-DMSO) δ (ppm): 9.86 (s, 1H), 8.39-8.22 (m, 14H), 8.10-8.07 (t, 4H), 7.88 (d, 2H), 7.74 (d, 4H), 7.52 (d, 4H), 7.25 (d, 2H).

[0061] (2) Preparation of pTPAPy

[0062] pTPA-CHO (337 mg, 0.5 mmol) and 1,4-dimethylpyridinium-1-iodide (168 mg, 0.7 mmol) were dissolved in a mixture of THF (4 mL) and methanol (12 mL), and then 10 μL of pyridine was added and refluxed for 12 h. After the mixture was cooled, the solvent was evaporated, and then extracted with DCM three times, and then DCM was evaporated, and the resulting product was placed in petroleum ether and refluxed overnight to obtain red powder pTPAPy (235 mg).

[0063] The characterization data of the obtained pTPAPy are: 1 H NMR (400MHz, d-DMSO) δ = 8.81 (d, 2H), 8.41-8.10 (m, 21H), 7.80-7.73 (m, 6H), 7.50 (d, 4H), 7.34 (m, 3H).

[0064] Example 2

[0065] An aggregation-induced luminescence charge-type free radical photosensitizer, the structural formula of which is:

[0066]

[0067] The synthetic route is:

[0068]

[0069] The specific preparation process is:

[0070] (1) Preparation of TPAFBZ-Br

[0071] 4,7-Dibromo-5,6-difluoro-benzothiadiazole (5mmol, 1.64g), triphenylamine boric acid (6mmol, 1.73g), Pd(PPh3)4 (116mg) were placed in a two-necked flask. N2 was filled in, and under the protection of N2, THF (20mL) and K2CO3 aqueous solution (2M, 8mL) were injected into the flask. Reflux reaction for 12h. After the reaction was completed, the reaction solution was extracted three times with DCM and yellow powder TPAFBZ-Br (734mg) was obtained by column chromatography.

[0072] (2) Preparation of TPAFBZ-CHO

[0073] TPAFBZ-Br (2mmol, 986mg), 4-formylphenylboronic acid (3mmol, 450mg), and Pd(PPh3)4 (46mg) were placed in a two-necked flask. N2 was filled in, and THF (20mL) and K2CO3 aqueous solution (2M, 8mL) were injected into the flask under N2 protection. The reaction was refluxed for 12h. After the reaction was completed, the reaction solution was extracted three times with DCM, and light red powder TPAFBZ-CHO (738mg) was obtained by column chromatography.

[0074] The characterization data of the obtained TPAFBZ-CHO are: 1 H NMR (400MHz, d-DMSO) δ = 10.13 (s, 1H), 8.14-8.03 (m, 4H), 7.76 (d, 2H), 7.41-7.15 (m, 12H).

[0075] (3) Preparation of TPAFBZPy

[0076] TPABZ-CHO (259 mg, 0.5 mmol) and 1,4-dimethylpyridinium-1-iodide (168 mg, 0.7 mmol) were dissolved in THF (4 mL) and methanol (12 mL), and then 10 μL of piperidine was added and refluxed for 12 h. After the mixture was cooled, the solvent was evaporated, and then extracted with DCM three times, after which DCM was evaporated, and the resulting product was placed in petroleum ether and refluxed overnight to obtain black powder TPAFBZPy (287 mg).

[0077] The characterization data of the obtained TPAFBZPy are: 1 H NMR (400MHz, d-DMSO) δ = 8.92 (d, 2H), 8.30 (d, 1H), 8.15-7.97 (m, 3H), 7.77-7.75 (m, 4H), 7.41-7.39 (m, 6H), 7.17-7.15 (d, 8H), 4.29 (s, 3H).

[0078] Figure 1 The UV absorption spectrum and fluorescence spectrum of the photosensitizer prepared in Example 1-2 in dichloromethane solvent. Figure 1 It can be seen that the maximum absorption peaks of pTPAPy and TPAFBZPy are at 520nm and 428nm, respectively, while the maximum fluorescence peaks of pTPAPy and TPAFBZPy are at 665nm and 643nm, respectively. This indicates that pTPAPy has longer absorption and fluorescence wavelengths than TPAFBZPy, preliminarily indicating that the intramolecular charge transfer effect of pTPAPy is stronger than that of TPAFBZPy.

[0079] Figure 2 The fluorescence emission spectra of the photosensitizer (10 μM) prepared in Example 1-2 in a dimethyl sulfoxide / toluene mixed solvent as the toluene content increases, wherein (A) is pTPAPy and (B) is TPAFBZPy. Figure 2 It can be seen that the photosensitizer prepared in Example 1-2 emits weak light in pure dimethyl sulfoxide solvent. With the addition of poor solvent toluene, the fluorescence begins to gradually increase. When the toluene content is increased to 90%, the fluorescence intensity reaches the strongest state, indicating that both pTPAPy and TPAFBZPy photosensitizers have aggregation-induced emission characteristics.

[0080] The photosensitizer (2.5 μM) prepared in Example 1-2 was monitored by using H2DCF-DA (5 μM) fluorescent probe under white light (the power of the white light lamp was 50 mW / cm 2 ) to produce ROS under irradiation, the results are shown in Figure 3 . Figure 3 The performance of the photosensitizer prepared in Example 1-2 in generating ROS under white light irradiation, wherein (A) is pTPAPy and (B) is TPAFBZPy. Figure 3 It can be seen that the photosensitizer prepared in Example 1-2 significantly improves the fluorescence intensity of the H2DCF-DA probe under white light irradiation. pTPAPy enhances the fluorescence of the H2DCF-DA probe by 26 times, while TPAFBZPy enhances the fluorescence of the H2DCF-DA probe by 24.6 times, indicating that both pTPAPy and TPAFBZPy can effectively generate ROS.

[0081] Using ABDA (20 μM) absorption probe, the photosensitizer (2.0 μM) prepared in Example 1-2 was monitored under white light (the power of the white light lamp was 50 mW / cm 2 ) to produce singlet oxygen species under irradiation, the results are shown in Figure 4 . Figure 4The performance of the photosensitizer prepared in Example 1-2 in generating singlet oxygen under white light irradiation, wherein (A) is pTPAPy and (B) is TPAFBZPy. Figure 4 It can be seen that under white light irradiation, the absorption intensity of the ABDA probe of the photosensitizer prepared in Example 1-2 is significantly reduced, and the rate at which the absorption intensity of the ABDA probe decreases due to pTPAPy is significantly faster than that due to TPAFBZPy, indicating that compared with TPAFBZPy, the pTPAPy photosensitizer has a more efficient singlet oxygen production ability.

[0082] Using DHR123 (1.0 μM) fluorescent probe, the photosensitizer (2.0 μM) prepared in Example 1-2 was monitored under white light (the power of the white light lamp was 50 mW / cm 2 ) to produce superoxide anion radicals and reactive oxygen species. Figure 5 . Figure 5 The performance of the photosensitizer prepared in Example 1-2 in generating superoxide anion radical active oxygen under white light irradiation conditions, wherein (A) is pTPAPy and (B) is TPAFBZPy. Figure 5 It can be seen that the photosensitizer prepared in Example 1-2 significantly improves the fluorescence intensity of the DHR123 probe under white light irradiation. pTPAPy enhances the fluorescence of the DHR123 probe by 54 times, while TPAFBZPy enhances the fluorescence of the DHR123 probe by 47 times, indicating that both pTPAPy and TPAFBZPy can effectively generate superoxide anion free radical reactive oxygen.

[0083] HPF (5.0 μM) fluorescent probe was used to monitor the photosensitizer (2.0 μM) prepared in Example 1-2 under white light (the power of the white light was 50 mW / cm 2 ) to produce hydroxyl radical active oxygen under irradiation, the results are shown in Figure 6 . Figure 6 The photosensitizer prepared in Example 1-2 generates hydroxyl radical active oxygen under white light irradiation. Figure 6 It can be seen that the fluorescence intensity of the HPF probe of the photosensitizer prepared in Example 1-2 is significantly improved under white light irradiation. HPF enhances the fluorescence of the HPF probe by 257 times, while TPAFBZPy enhances the fluorescence of the HPF probe by 57 times, indicating that compared with TPAFBZPy, the pTPAPy photosensitizer has a more efficient ability to generate hydroxyl radical reactive oxygen species.

[0084] Figure 7 This is a graph showing the fluorescence staining effect of pTPAPy (10.0 μM) prepared in Example 1 on Escherichia coli (Gram-negative bacteria). Figure 7It can be seen that the pTPAPy photosensitizer cannot enter E. coli and is only outside the bacteria, indicating that the pTPAPy photosensitizer cannot fluorescently stain E. coli.

[0085] Figure 8 This is a fluorescence staining effect diagram of pTPAPy (10.0 μM) prepared in Example 1 on Staphylococcus aureus (Gram-positive bacteria). Figure 8 It can be seen that the pTPAPy photosensitizer can quickly enter Staphylococcus aureus, indicating that the pTPAPy photosensitizer can specifically fluorescently stain Staphylococcus aureus.

[0086] Fig. 9 This is a fluorescence staining effect diagram of pTPAPy (10.0 μM) prepared in Example 1 on methicillin-resistant Staphylococcus aureus (resistant bacteria). Fig. 9 It can be seen that the pTPAPy photosensitizer can quickly enter the methicillin-resistant Staphylococcus aureus, indicating that the pTPAPy photosensitizer can specifically fluorescently stain methicillin-resistant Staphylococcus aureus.

[0087] The pTPAPy prepared in Example 1 was dissolved in dimethyl sulfoxide to obtain pTPAPy culture solutions of different concentrations (0, 0.125 μM, 0.25 μM, 0.5 μM, 1 μM, 1.25 μM, 2.5 μM, 5 μM, 10 μM, 20 μM). The pTPAPy culture solutions with concentrations of 0, 5 μM, 10 μM, and 20 μM were respectively used in the absence of light and the light condition (white light power of 50 mW / cm 2 ) and observed the survival of E. coli after 10 minutes. The results are shown in Fig.10 The pTPAPy culture medium with concentrations of 0, 0.125 μM, 0.25 μM, 0.5 μM, and 1 μM was used in the absence of light and under light conditions (white light power of 50 mW / cm 2 ) and the survival of Staphylococcus aureus was observed after 10 minutes. The results are shown in Fig.11 The pTPAPy culture medium with concentrations of 0, 1.25 μM, 2.5 μM, 5 μM, and 10 μM was used in the absence of light and under light conditions (white light power of 50 mW / cm 2 ) and observed the survival of methicillin-resistant Staphylococcus aureus after 10 minutes. Fig.12 .

[0088] Fig.10 The photodynamic antibacterial effect of different concentrations of pTPAPy on Escherichia coli is shown in Figure 2. Fig.10It can be seen that with the increase of the culture concentration of pTPAPy photosensitizer, Escherichia coli can be basically killed after irradiation with white light, indicating that pTPAPy photosensitizer has a good photodynamic antibacterial effect on Escherichia coli.

[0089] Fig.11 The photodynamic antibacterial effect of pTPAPy at different concentrations on Staphylococcus aureus is shown in Figure 2. Fig.11 It can be seen that with the increase of the culture concentration of pTPAPy photosensitizer, Staphylococcus aureus can be basically killed after white light irradiation, indicating that pTPAPy photosensitizer has a good photodynamic antibacterial effect on Staphylococcus aureus.

[0090] Fig.12 The photodynamic antibacterial effect of different concentrations of pTPAPy on methicillin-resistant Staphylococcus aureus. Fig.12 It can be seen that with the increase of the culture concentration of pTPAPy photosensitizer, the methicillin-resistant Staphylococcus aureus can be basically killed after irradiation with white light, indicating that pTPAPy photosensitizer has a good photodynamic antibacterial effect on methicillin-resistant Staphylococcus aureus.

[0091] The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A type of aggregation-induced emission charge-type free radical photosensitizer, characterized in that: Its general structural formula is: In the formula, R1 is hydrogen or an aromatic condensed ring, R2 is benzothiadiazole, a benzothiadiazole derivative or a carbon-carbon double bond, R3 is an alkyl group, and X- is an anion pair.

2. The aggregation-induced emission charge-type free radical photosensitizer according to claim 1, characterized in that: The aromatic fused ring is one of (a)-(d); the structural formula of (a)-(d) is as follows:

3. The aggregation-induced emission charge-type free radical photosensitizer according to claim 1, characterized in that: The R3 is any one of the alkyl groups with a carbon chain number ≤ 18.

4. The aggregation-induced emission charge-type free radical photosensitizer according to claim 3, characterized in that: The R3 is one of methyl, ethyl, propyl, butyl, isobutyl, tert-butyl and hexyl.

5. The aggregation-induced emission charge-type free radical photosensitizer according to claim 1, characterized in that: The X- is one of iodide ion, bromide ion, hydroxide ion, tetrafluoroborate ion, nitrate ion, sulfate ion and hexafluorophosphate ion.

6. A method for preparing the aggregation-induced emission charge-type free radical photosensitizer according to any one of claims 1 to 5, characterized in that: The following steps are involved: A triphenylamine derivative and 1-pyreneboronic acid or 4,7-dibromo-5,6-difluoro-benzothiadiazole, a triphenylamine derivative and 4-formylphenylboronic acid are used as raw materials, and an intermediate product is obtained through a Suzuki coupling reaction; the intermediate product and a charged pyridine derivative are subjected to an Aldol dehydration condensation reaction under the action of a catalyst to obtain the aggregation-induced luminescence charged free radical photosensitizer.

7. The preparation method according to claim 6, characterized in that: The molar ratio of the triphenylamine derivative to 1-pyreneboronic acid is 2:5; the molar ratio of the 4,7-dibromo-5,6-difluoro-benzothiadiazole, the triphenylamine derivative and 4-formylphenylboronic acid is 5:6:

3.

8. The preparation method according to claim 6, characterized in that: The reaction time of the Suzuki coupling reaction and the Aldol dehydration condensation reaction is 12 hours.

9. Use of the aggregation-induced emission charged free radical photosensitizer according to any one of claims 1 to 5 in the preparation of a drug for specific fluorescent recognition of Gram-positive bacteria.

10. Use of the aggregation-induced emission charge-type free radical photosensitizer according to any one of claims 1 to 5 in the field of preparing photodynamic antibacterial drugs.

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