Photosensitive molecule as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of photodynamics, and particularly relates to a photosensitive molecule and a preparation method and application thereof. The structure of the photosensitive molecule is shown in the specification. The photosensitive molecule can be used as an I-type photosensitive molecule to be specifically combined with DNA G4 so as to effectively achieve the effect of photodynamic therapy or photodynamic sterilization.

Description

Technical Field

[0001] This invention belongs to the field of photodynamic technology, specifically relating to a photosensitive molecule, its preparation method, and its application. Background Technology

[0002] The global spread of bacterial resistance has become a serious challenge threatening public health. The emergence of multidrug-resistant strains has rendered traditional antibiotics ineffective in clinical treatment, making the development of novel, antibiotic-free antibacterial strategies imperative. Antibacterial photodynamic therapy (aPDT) has become a research hotspot in recent years due to its broad-spectrum antibacterial activity and low resistance-inducing properties. The core of aPDT lies in the photosensitizer (PS), which, under specific wavelengths of light, induces the production of reactive oxygen species (ROS) through photosensitization via energy or electron transfer, thereby efficiently killing pathogens and providing a new approach to solving the problem of bacterial resistance.

[0003] Despite the promising prospects of aPDT, its efficiency and application in complex infection environments (such as biofilms and hypoxic areas) still face significant limitations, with the key bottleneck being the insufficient performance of existing photosensitizer systems. Based on the ROS generation mechanism, photosensitizers can be classified into type I and type II: type II photosensitizers react with oxygen through energy transfer to generate singlet oxygen (ROS). 1 O2), but it is highly dependent on oxygen concentration, and its effectiveness is greatly reduced in the hypoxic infection microenvironment; Type I photosensitizers generate more active and less oxygen-dependent ROS (such as •OH, O2) through electron transfer. - • ), which has greater application potential in hypoxic environments. However, existing type I photosensitizers have drawbacks such as low electron transfer efficiency, the need to introduce exogenous electron donors / acceptors to improve performance (increasing system complexity and difficulty in clinical translation), and lack of specific targeting ability for bacterial nucleic acids, resulting in insufficient antibacterial efficiency and targeting, which limits the practical application of aPDT.

[0004] To address the shortcomings of existing type I photosensitizers, such as insufficient electron transfer efficiency, lack of specific targeting ability for bacterial nucleic acids, and limited applicability in complex infection environments, the development of novel type I photosensitizers that combine high electron transfer performance, nucleic acid targeting, and hypoxia dependence is of great significance for improving the antibacterial efficiency of aPDT and expanding its application in the treatment of drug-resistant bacterial infections. Summary of the Invention

[0005] Therefore, the present invention aims to provide a photosensitive molecule, its preparation method, and its application. This can be used as a type I photosensitive molecule to specifically bind to DNA G4, thereby effectively achieving photodynamic therapy or photodynamic sterilization.

[0006] To achieve the above objectives, the present invention can adopt the following technical solutions: This invention provides a photosensitive molecule with the following structural formula: .

[0007] Another aspect of the present invention provides a method for preparing the above-mentioned photosensitive molecule, the method comprising: (1) 7-bromobenzo[c][1,2,5]thiadiazole-4-carboxaldehyde reacts with dimethylamine to give 7-(dimethylamino)benzo[c][1,2,5]thiadiazole-4-carboxaldehyde; (2) The photosensitive molecule was obtained by reacting 7-(dimethylamino)benzo[c][1,2,5]thiadiazole-4-carboxaldehyde and 6-methoxy-2,3-dimethylbenzo[d][1,3]selenoazole-3-onium.

[0008] Preferably, in the above preparation method, The reaction medium in step (1) is water; and / or Step (1) is carried out in an inert gas environment; and / or The reaction medium in step (2) is anhydrous ethanol; and / or Step (2) involves the reaction being carried out in an inert gas environment; and / or The reaction temperature in step (2) is 75℃-85℃.

[0009] In another aspect, the present invention provides a type I photosensitizer, which includes the above-mentioned photosensitizing molecule.

[0010] Preferably, the above-mentioned type I photosensitizer further includes one or more combinations of a carrier, dispersant, sensitizer, synergist, stabilizer, targeting molecule, solvent or cosolvent.

[0011] In another aspect, the present invention provides a photodynamic therapeutic agent or a photodynamic bactericide, comprising the above-mentioned photosensitizing molecule or the above-mentioned type I photosensitizer.

[0012] In another aspect, the present invention provides the application of the above-mentioned photosensitizing molecule or the above-mentioned type I photosensitizer in the preparation of photodynamic therapeutic drugs or photodynamic bactericides.

[0013] Preferably, in the above applications, the photosensitizing molecule or type I photosensitizer specifically targets DNA G4.

[0014] In another aspect, the present invention provides the application of the above-mentioned photosensitizing molecule or the above-mentioned type I photosensitizer in sterilization.

[0015] Preferably, in the above applications, the photosensitizing molecule or type I photosensitizer specifically targets DNA G4.

[0016] In another aspect, the present invention provides a method for sterilization, the method comprising: mixing a photosensitive molecule or a type I photosensitizer with a sample to be treated and then irradiating it with light; wherein, the pH is adjusted to 2.4-8.6 after mixing.

[0017] The beneficial effects of this invention include: the photosensitive molecule provided by this invention can specifically bind to DNA G4 as a type I photosensitive molecule, thereby effectively achieving the effects of photodynamic therapy or photodynamic sterilization. Attached Figure Description

[0018] Figure 1 The synthetic route for the photosensitive molecule NBD-Se; Figure 2 The 1H NMR spectrum of 7-(dimethylamino)benzo[c][1,2,5]thiadiazole-4-carboxaldehyde; Figure 3 The carbon NMR spectrum of 7-(dimethylamino)benzo[c][1,2,5]thiadiazole-4-carboxaldehyde; Figure 4 The 1H NMR spectrum of the photosensitive molecule NBD-Se; Figure 5 The carbon NMR spectrum of the photosensitive molecule NBD-Se; Figure 6 Testing the photosensitive molecule NBD-Se using a DCFH probe; Figure 7 Testing the photosensitive molecule NBD-Se using ABDA probes; Figure 8 Testing the photosensitive molecule NBD-Se using SOSG probes; Figure 9 Testing the photosensitive molecule NBD-Se using the DHR123 probe; Figure 10 HPF probes were used to test the photosensitive molecule NBD-Se. Figure 11 The effect of different pH values ​​on NBD-Se fluorescence emission; Figure 12 The effects of different ions on the fluorescence emission of NBD-Se; Figure 13 The effect of photobleaching on NBD-Se fluorescence emission; Figure 14 Line graphs showing the selectivity of the photosensitive molecule NBD-Se for different G-tetrachains; Figure 15 Histogram of selective fluorescence intensity of photosensitive molecule NBD-Se for different G-tetrachains; Figure 16 Graphs showing fluorescence titration data of the photosensitive molecule NBD-Se with different G-tetrachains; Figure 17 Analysis of the detection limit of the photosensitive molecule NBD-Se for G-quadruplex DNA; Figure 18 The binding constant of the photosensitive molecule NBD-Se to G-quadruplex DNA; Figure 19 Job's plot fluorescence curves of photosensitive molecules NBD-Se and G4 mixed in different proportions; Figure 20 The results of the light-controlled experiment were conducted without the addition of the photosensitive molecule NBD-Se. Figure 21 The antibacterial experiment results are shown under different concentrations of the photosensitive molecule NBD-Se. Detailed Implementation

[0019] The embodiments described are provided to better illustrate the present invention, but are not intended to limit the scope of the invention to the embodiments described. Therefore, non-essential improvements and adjustments made to the embodiments by those skilled in the art based on the above description are still within the scope of protection of the present invention.

[0020] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. Singular expressions include plural expressions unless they have a distinct meaning in the context. As used herein, it should be understood that terms such as “comprising,” “having,” “including,” are intended to indicate the presence of features, numbers, operations, components, parts, elements, materials, or combinations thereof. The terminology of the invention is disclosed in the specification and is not intended to exclude the possibility that one or more other features, numbers, operations, components, parts, elements, materials, or combinations thereof may be present or added. As used herein, “ / ” may be interpreted as “and” or “or,” depending on the context.

[0021] In a first aspect, embodiments of the present invention provide a photosensitive molecule (NBD-Se), the structural formula of which is shown below: .

[0022] It should be noted that NBD-Se exhibits strong phototoxicity against *Escherichia coli* and *Staphylococcus aureus* under light conditions. This invention organically combines nucleic acid targeting capability with a highly efficient type I photosensitization mechanism, aiming to achieve local enrichment of the photosensitizer at bacterial nucleic acid sites and the resulting high concentrations of ROS (such as •OH and O2). - • This achieves direct destruction of bacterial genetic material, thereby achieving efficient and precise antibacterial effects.

[0023] Secondly, embodiments of the present invention provide a method for preparing the above-mentioned photosensitive molecule, the method comprising: (1) 7-bromobenzo[c][1,2,5]thiadiazole-4-carboxaldehyde reacts with dimethylamine to give 7-(dimethylamino)benzo[c][1,2,5]thiadiazole-4-carboxaldehyde; (2) The photosensitive molecule was obtained by reacting 7-(dimethylamino)benzo[c][1,2,5]thiadiazole-4-carboxaldehyde and 6-methoxy-2,3-dimethylbenzo[d][1,3]selenoazole-3-onium.

[0024] It should be noted that 7-bromobenzo[c][1,2,5]thiadiazole-4-carboxaldehyde, dimethylamine, 7-(dimethylamino)benzo[c][1,2,5]thiadiazole-4-carboxaldehyde, and 6-methoxy-2,3-dimethylbenzo[d][1,3]selenazole-3-onium are all well known in the art, and their structures are shown below: 7-Bromobenzo[c][1,2,5]thiadiazole-4-carboxaldehyde: ; Dimethylamine: ; 7-(dimethylamino)benzo[c][1,2,5]thiadiazole-4-carboxaldehyde: ; 6-Methoxy-2,3-dimethylbenzo[d][1,3]selenozol-3-onium: .

[0025] In some specific examples, in the above preparation method, The reaction medium in step (1) is water; and / or Step (1) is carried out in an inert gas environment; and / or The reaction medium in step (2) is anhydrous ethanol; and / or Step (2) involves the reaction being carried out in an inert gas environment; and / or The reaction temperature in step (2) is 75℃-85℃.

[0026] It should be noted that the method for preparing the photosensitive molecule of the present invention can preferably be carried out according to the reaction conditions exemplified above.

[0027] Thirdly, embodiments of the present invention provide a type I photosensitizer, which includes the aforementioned photosensitizing molecule.

[0028] It should be noted that the photosensitive molecule in this invention can be prepared into a type I photosensitizer by adding excipients, which are known in the art.

[0029] In some specific examples, the aforementioned type I photosensitizers also include one or more combinations of carriers, dispersants, sensitizers, synergists, stabilizers, targeting molecules, solvents, or cosolvents.

[0030] Fourthly, embodiments of the present invention provide a photodynamic therapy drug or a photodynamic bactericide, comprising the above-mentioned photosensitizing molecule or the above-mentioned type I photosensitizer.

[0031] Fifthly, embodiments of the present invention provide the application of the above-mentioned photosensitizing molecule or the above-mentioned type I photosensitizer in the preparation of photodynamic therapy drugs or photodynamic bactericides.

[0032] In some specific examples, in the applications described above, the photosensitizing molecule or type I photosensitizer specifically targets DNA G4.

[0033] Sixthly, embodiments of the present invention provide the application of the above-mentioned photosensitizing molecule or the above-mentioned type I photosensitizer in sterilization.

[0034] In some specific examples, in the applications described above, the photosensitizing molecule or type I photosensitizer specifically targets DNA G4.

[0035] In a seventh aspect, embodiments of the present invention provide a method for sterilization, the method comprising: mixing a photosensitive molecule or a type I photosensitizer with a sample to be treated and then irradiating it with light; wherein, the pH is adjusted to 2.4-8.6 after mixing.

[0036] It should be noted that the fluorescence intensity of the photosensitive molecule or type I photosensitizer in this invention does not fluctuate much with pH changes in an environment of pH 2.4-8.6.

[0037] To better understand the present invention, specific examples are provided below to further illustrate the content of the present invention, but the content of the present invention is not limited to the examples below.

[0038] Preparation Examples Example 1 According to the embodiments of the present invention Figure 1 The synthetic route shown below synthesizes the photosensitive molecule NBD-Se. The specific steps are as follows: (1) 1.00 g of 7-bromobenzo[c][1,2,5]thiadiazole-4-carboxaldehyde was added to 10 mL of deionized water, and 187 mg of dimethylamine was added dropwise. The reaction was then protected by nitrogen. After 4 h of reaction, the mixture was extracted three times with dichloromethane (DCM, 100 mL), and the lower liquid was obtained after separation. The lower liquid was combined and distilled under reduced pressure to obtain a solid. The solid was then purified by column chromatography to obtain 7-(dimethylamino)benzo[c][1,2,5]thiadiazole-4-carboxaldehyde. (2) Dissolve 1.00 g of 7-(dimethylamino)benzo[c][1,2,5]thiadiazole-4-carboxaldehyde in anhydrous ethanol (10 mL), and then add 1.17 g of 6-methoxy-2,3-dimethylbenzo[d][1,3]selenozolium-3-onium; then stir for 6 hours under nitrogen protection at 80 °C to obtain the photosensitive molecule NBD-Se (hereinafter referred to as NBD-Se).

[0039] Characterization test The 1H NMR spectrum of 7-(dimethylamino)benzo[c][1,2,5]thiadiazole-4-carboxaldehyde prepared in Example 1 ( 1 The HNMR data are shown below: 1 ¹H NMR (500 MHz, DMSO) δ 10.25 (s, 1H), 8.07 (s, 1H), 6.64 (s, 1H), 3.55 (s, 6H); ¹H NMR spectrum as follows: Figure 2 As shown.

[0040] Carbon NMR spectrum of 7-(dimethylamino)benzo[c][1,2,5]thiadiazole-4-carboxaldehyde prepared in Example 1 ( 1 The CNMR data is shown below: 13 CNMR (126MHz, DMSO) δ 186.48, 155.88, 148.06, 136.76, 132.58, 115.67, 105.36, 43.10; C NMR spectrum as follows Figure 3 As shown.

[0041] The 1H NMR spectrum of NBD-Se prepared in Example 1 ( 1 The HNMR data are shown below: 1 ¹H NMR (500 MHz, DMSO) δ 8.29 (s, 2H), 8.22 (s, 1H), 8.13 (s, 2H), 7.50 (s, 1H), 7.19 (s, 1H), 6.70 (s, 1H), 4.12 (s, 3H), 3.92 (s, 3H), 3.60 (s, 6H); ¹H NMR spectrum as follows: Figure 4 As shown.

[0042] Carbon NMR spectrum of NBD-Se prepared in Example 1 ( 1 The CNMR data is shown below: 13 CNMR (126MHz, CDCl3) δ 159.41, 151.48, 148.19, 145.58, 130.67, 119.71, 118.25, 114.50, 110.65, 104.77, 59.95, 47.24, 33.48; CMR spectra are as follows: Figure 5 As shown.

[0043] Application testing (a) Reactive oxygen species fluorescent probe test To assess the generation capacity of reactive oxygen species (ROS), compound NBD-Se (2.0 μM) was co-incubated with DCFH-DA (2.0 μM) with or without RNAG4 (2.0 μM). This was aimed at singlet oxygen (ROS). 1 For the detection of superoxide anion (O2), NBD-Se was incubated with ABDA (2 μM, dissolved in DMSO) or SOSG (2 μM, dissolved in methanol) with or without the addition of RNA G4. - For the detection of hydroxyl radicals (•OH), DHR123 (2 μM) and HPF (2 μM) were used as fluorescent probes, respectively, and were co-treated with NBD-Se in the presence or absence of RNA G4. All samples were tested under an LED light source (620 nm, 10 mW / cm²). 2 Irradiation was performed for 10 minutes. To dynamically monitor the ROS generation process, fluorescence or absorption spectra of the corresponding indicators were collected at different irradiation time points.

[0044] (1) By adding the DCFH probe (2',7'-dichlorodihydrofluorescein) to the probe and then irradiating it with 620nm ultraviolet light, the total reactive oxygen species of NBD-Se were measured as follows: Figure 6 As shown in the results, the comparison revealed that the fluorescence intensity at 525 nm increased by 4 times after the probe was added, indicating that the total reactive oxygen species (ROS) level changed.

[0045] (2) By adding ABDA probe (9,10-anthratridimyl-bis(methylene)dimalonic acid) to the probe and then subjecting it to 620 nm ultraviolet light irradiation, the NBD-Se production was measured. 1 The UV-Vis absorption spectrum of O2 capacity is shown in the figure. Figure 7 As shown, the results indicate that the photosensitive molecule NBD-Se does not produce singlet oxygen ( 1 O2).

[0046] (3) The NBD-Se product was detected by adding SOSG probe to the probe and then irradiating it with 620nm ultraviolet light. 1 The fluorescence spectrum of O2 capacity is shown in the figure. Figure 8 As shown, the results indicate that NBD-Se does not produce singlet oxygen ( 1 O2).

[0047] (4) The superoxide anion level (O2•) of NBD-Se was detected by adding DHR123 probe to the probe and then irradiating it with 620 nm ultraviolet light. - The fluorescence spectrum of ) is shown in the following results. Figure 9 As shown.

[0048] (5) The fluorescence spectrum of hydroxyl radical level (·OH) of NBD-Se was detected by adding HPF probe to the probe and then irradiating it with 620 nm ultraviolet light. The results are as follows: Figure 10 As shown.

[0049] The data in (1) to (3) prove that NBD-Se is indeed a type I photosensitive molecule.

[0050] (II) Investigation of different factors affecting NBD-Se fluorescence emission (1) Effect of pH on NBD-Se fluorescence emission The stability of NBD-Se under different pH conditions was tested, specifically the effect of pH on probe fluorescence emission under 660 nm excitation. The results are as follows: Figure 11 As shown, the results indicate that the fluorescence intensity of NBD-Se does not fluctuate significantly with pH changes within the pH range of 2.4–8.6.

[0051] (2) Effects of different ions on NBD-Se fluorescence emission The effects of different ions on the fluorescence emission of NBD-Se were tested, and the results are as follows: Figure 12 As shown, the results indicate that, under the influence of different cations and anions, the fluorescence intensity of NBD-Se does not fluctuate much with the changes in ions, and its fluorescence intensity is significantly weaker than that of G4.

[0052] (3) Effect of photobleaching on NBD-Se fluorescence emission The effect of photobleaching on NBD-Se fluorescence emission was tested, and the results are as follows: Figure 13 As shown, the results indicate that NBD-Se still exhibits a relatively high fluorescence intensity from 10 μmol to 100 μmol, demonstrating excellent photostability.

[0053] (4) Effect of different selectivity of G4 on NBD-Se fluorescence emission The effect of different selectivities of G4 on fluorescence emission was tested, and the results are as follows: Figure 14 and Figure 15 As shown in the results, DNAG4 and HUM24 exhibit significantly higher selectivity than other G4s under different G4 conditions.

[0054] (III) Linearity test of NBD-Se on G-quadruplex To further investigate the feasibility of NBD-Se as a fluorescent probe for G-quadruplexes, the sensitivity of NBD-Se to G-quadruplexes was studied through a fluorescence titration experiment of NBD-Se and G-quadruplex DNA. Specifically, parallel G-quadruplexes HUM24, OXY28, and BOM17 were selected as research subjects. The concentration of NBD-Se was fixed, and a certain amount of G4 sequence was gradually added to the solution system, followed by scanning its fluorescence spectrum.

[0055] The results are as follows Figure 16 As shown in the figure, the fluorescence emission gradually increases with increasing concentration until titration stops when the fluorescence emission intensity reaches saturation. It can be observed from the figure that the fluorescence intensity of the photosensitizer NBD-Se significantly increases with increasing G4 sequence concentration.

[0056] In addition, to test the sensitivity of NBD-Se to G-quadruplex DNA, the detection limit analysis results of NBD-Se are as follows: Figure 17 As shown in the results, NBD-Se and G-quadruplex DNA have low LOD values ​​and high detection sensitivity and stability.

[0057] (iv) Combining constant Ka value test The binding constant Ka value is one of the important parameters for evaluating whether a compound can serve as a fluorescent probe for G-quadruplex DNA. Therefore, the binding ability of NBD-Se to G-quadruplex DNA can be investigated through fluorescence titration experiments to screen small molecule compounds with good recognition ability for G-quadruplex DNA. Specifically, based on the selectivity of NBD-Se for different G-quadruplexes, the three G-quadruplexes with the best selectivity, HUM24, OXY28, and BOM17 (all G-quadruplexes are from Sangon Biotech (Shanghai) Co., Ltd.), were selected for titration experiments; at room temperature, fluorescence titration spectra were scanned according to their different excitation wavelengths, and the binding constants of different compounds for G-quadruplex DNA were calculated according to the formula.

[0058] The results are as follows Figure 18 As shown in the results, the fluorescence response of NBD-Se after binding to the G-quadruplex DNAHUM24 was much stronger than that of other fluorescence responses. This further confirms that NBD-Se has good specific recognition ability and excellent binding ability to the G-quadruplex.

[0059] (v) Test of the binding ratio of NBD-Se and G4 This invention also tested the Job'splot fluorescence curves of NBD-Se and G4 mixed in different proportions, and the results are as follows: Figure 19As shown, the results indicate that NBD-Se forms a complex with a stoichiometric ratio of 1:1 with G4HUM24, OXY28, and BOM17.

[0060] (vi) Photodynamic antibacterial performance test of NBD-Se To evaluate the photodynamic antibacterial properties of the probe NBD-Se, this invention uses *Escherichia coli* as a representative strain of Gram-negative bacteria, suspending it in PBS buffer for co-culture experiments with bacterial suspensions. Specifically, this includes: First, a light control experiment was conducted under conditions without the addition of NBD-Se. The results are as follows: Figure 20 As shown in the figure, the results indicate that the number of colonies did not change significantly regardless of whether the light source was exposed to light, indicating that the light source itself does not have antibacterial activity. Subsequently, antibacterial experiments were conducted under different concentrations of NBD-Se, and the results are as follows: Figure 21 As shown, the results indicate that under light conditions, the number of colonies decreased significantly after the addition of NBD-Se, and the number of colonies decreased significantly with the increase of NBD-Se concentration. When the NBD-Se concentration reached 2 μM, it almost completely inhibited colony formation, demonstrating its highly efficient antibacterial activity under light conditions. In contrast, under no-light conditions, the number of colonies in each experimental group did not change significantly.

[0061] The above results collectively confirm that NBD-Se has significant antibacterial activity under light conditions, but does not show obvious antibacterial activity under dark conditions.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A photosensitive molecule, the structural formula of which is shown below: 。 2. The method for preparing the photosensitive molecule according to claim 1, characterized in that, Preparation methods include: (1) 7-bromobenzo[c][1,2,5]thiadiazole-4-carboxaldehyde reacts with dimethylamine to give 7-(dimethylamino)benzo[c][1,2,5]thiadiazole-4-carboxaldehyde; (2) The photosensitive molecule was obtained by reacting 7-(dimethylamino)benzo[c][1,2,5]thiadiazole-4-carboxaldehyde and 6-methoxy-2,3-dimethylbenzo[d][1,3]selenoazole-3-onium.

3. The preparation method according to claim 2, characterized in that, The reaction medium in step (1) is water; and / or Step (1) is carried out in an inert gas environment; and / or The reaction medium in step (2) is anhydrous ethanol; and / or Step (2) involves the reaction being carried out in an inert gas environment; and / or The reaction temperature in step (2) is 75℃-85℃.

4. A type I photosensitizer, characterized in that, Type I photosensitizers include the photosensitizing molecules described in claim 1.

5. The type I photosensitizer according to claim 4, characterized in that, Type I photosensitizers also include one or more combinations of carriers, dispersants, sensitizers, synergists, stabilizers, targeting molecules, solvents, or cosolvents.

6. A photodynamic therapy drug or photodynamic bactericide, characterized in that, Includes the photosensitive molecule as described in claim 1 or the type I photosensitizer as described in claim 4 or 5.

7. The use of the photosensitizer of claim 1 or the type I photosensitizer of claim 4 or 5 in the preparation of photodynamic therapy drugs or photodynamic bactericides.

8. The application of the photosensitive molecule of claim 1 or the type I photosensitizer of claim 4 or 5 in sterilization.

9. The application according to claim 7 or 8, characterized in that, Photosensitive molecules or type I photosensitizers specifically target DNAG4.

10. A method for sterilization, characterized in that, The method includes: mixing a photosensitive molecule or a type I photosensitizer with the sample to be treated and then irradiating it with light; wherein the pH is adjusted to 2.4-8.6 after mixing.

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