Water-soluble organic conjugated molecules with different rigid-flexible structures and applications thereof

Abstract

The application provides a novel organic conjugated molecule, a long conjugated D-pi-A structure of which makes the organic conjugated molecule more likely to form a high positive charge density nanoparticle, and a large amount of active oxygen generated under white light irradiation can efficiently crack a bacterial cell membrane, and slow down the generation of bacterial drug resistance. The organic conjugated molecule shown in formula (I) has a strong photodynamic killing effect on gram-negative bacteria and gram-positive bacteria, has a low hemolysis rate, and has good biocompatibility. The application provides guidance for developing a high-efficiency and low-toxicity photodynamic antibacterial agent.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of biochemistry, and particularly relates to a kind of water-soluble organic conjugated molecules with different rigid-flexible structures and its application in antibacterial. BACKGROUND

[0002] Currently, diseases caused by pathogenic bacteria pose a significant threat to public health, especially the emergence of multi-drug resistant bacteria (MDR), making conventional antibiotic therapy difficult. Photodynamic therapy (PDT) is a non-invasive antibacterial method that uses photosensitizers (Ps) to absorb light to initiate photochemical reactions (type I and type II) to produce various reactive oxygen species to kill bacteria. Because PDI is a non-invasive antibacterial method, it is not easy to cause bacteria to develop resistance and cause side effects, and has the advantages of flexibility, controllability, high efficiency, low cost, etc., and has become a new type of antibacterial technology. However, the photosensitization performance and stability of organic photosensitizers are limited, which restricts the practical application of organic photosensitizers in PDI. In order to improve the photosensitization activity of organic photosensitizers with conjugated backbone, researchers have proposed various strategies, such as designing organic-inorganic or organic-organic heterojunctions, constructing donor-acceptor (D-A) or donor-π-acceptor (D-π-A) structures, enhancing hydrophilicity and expanding light absorption range, etc. Among these strategies, the unique molecular structure and photoelectric properties of D-π-A structure make it advantageous in PDT. First, in the D-π-A structure, the intrinsic electron push-pull effect between the donor unit and the acceptor unit can promote light-induced charge separation, thereby improving the photosensitization activity of the photosensitizer. And the photosensitizer with D-π-A structure can effectively separate the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), thereby reducing the singlet-triplet energy gap (ΔEST), enhancing the ISC process, and thereby improving photosensitization. In addition, photosensitizers with D-π-A structure have extremely high light stability and excellent near-infrared absorption capacity. Adjusting the conjugation degree (composition) of the donor part of the D-π-A structure can significantly affect the rigidity-flexibility, photo-physical properties, energy level structure and photochemical activity of the molecule, etc. In addition, the rigidity-flexibility of the photosensitizer molecule will affect the production of reactive oxygen species (ROS) by photosensitizer sensitized oxygen, and affect the binding mode of photosensitizer with cells, thereby affecting the delivery of ROS, ultimately leading to different bactericidal effects. Therefore, it is of great significance to develop photosensitizers with excellent photo-physical properties, high ROS generation capacity and good affinity with bacteria through reasonable molecular design. SUMMARY

[0003] The purpose of the present application is to provide a kind of water-soluble organic conjugated molecules with different rigid-flexible structures and its preparation method and application, which has good ROS generation capacity and strong binding capacity with bacteria, and shows excellent antibacterial effect, and provides guidance for the development of efficient photodynamic antibacterial agents.

[0004] The present application provides an organic conjugated molecular compound, whose structural formula is shown in formula (I),

[0005]

[0006] wherein n is an integer selected from 2-12;

[0007] X is halogen (for example, fluorine F, chlorine Cl, bromine Br, iodine I);

[0008] selected from C6-20 aryl, 5-20 membered heteroaryl;

[0009] selected from 5-20 membered heteroaryl containing N atom.

[0010] According to an embodiment of the present application, n is an integer selected from 3-10, for example, 3, 4, 5, 6, 7, 8, 9, 10.

[0011] According to an embodiment of the present application, X is Br.

[0012] According to an embodiment of the present application, selected from C6-16 aryl, 5-16 membered heteroaryl; preferably, it is selected from C6-10 aryl, 5-10 membered heteroaryl. According to an embodiment of the present application, selected from: phenyl, naphthyl, thienyl, furanyl, for example, phenyl, thienyl. According to an embodiment of the present application, selected from denotes the connecting site of the group.

[0013] According to an embodiment of the present application, selected from 5-16 membered heteroaryl containing N atom; preferably, the N atom is connected with phenyl; preferably, it is selected from carbazole, diphenylamine. According to an embodiment of the present application, selected from denotes the connecting site of the group.

[0014] According to an embodiment of the present application, the compound is selected from any one of the following formula (I-A), formula (I-B), formula (I-C):

[0015]

[0016] The present application also provides a preparation method of the compound shown in formula (I) above, which comprises the following steps:

[0017] (1) 4-methylpyridine and the compound shown in formula (II) undergo substitution reaction to obtain the compound shown in formula (III);

[0018]

[0019] wherein, X, n have the aforementioned definitions;

[0020] (2) the compound shown in formula (IV) and the compound shown in formula (V) undergo coupling reaction to obtain the compound shown in formula (VI);

[0021]

[0022] wherein, X has the aforementioned definition;

[0023] (3) the compound shown in formula (III) and the compound shown in formula (VI) undergo addition reaction to obtain the compound shown in formula (I).

[0024] According to the embodiment of the present application, in step (1), the molar ratio of the compound shown in formula (II) to 4-methylpyridine can be 1:(2-8), and specifically can be 1:5;

[0025] And / or, the temperature of the substitution reaction can be 60-90℃, and specifically can be 85℃;

[0026] And / or, the reaction time can be 6-12 hours, and specifically can be 10 hours;

[0027] And / or, the substitution reaction can be carried out in a solvent; preferably, the solvent can be any one of methanol, ethanol, propanol, and preferably ethanol.

[0028] According to the embodiment of the present application, in step (2), the molar ratio of the compound shown in formula (IV) to the compound shown in formula (V) can be 1:(1-1.5), and specifically can be 1:1;

[0029] And / or, the temperature of the coupling reaction can be 60-90℃, and specifically can be 80℃;

[0030] And / or, the reaction time can be 4-12 hours, and specifically can be 8 hours;

[0031] And / or, the coupling reaction is carried out under inert atmosphere, such as nitrogen atmosphere;

[0032] And / or, the coupling reaction is carried out under catalyst, such as tetrakis triphenylphosphine palladium;

[0033] And / or, the coupling reaction is carried out in the presence of base, such as potassium carbonate;

[0034] And / or, the coupling reaction is carried out in a solvent; preferably, the solvent can be a mixed solvent of tetrahydrofuran and water; the volume ratio of tetrahydrofuran and water is preferably (6-3):1, preferably 4:1.

[0035] According to the embodiments of the present application, in step (3), the molar ratio of the compound of formula (III) to the compound of formula (VI) can be 1:(2-2.3), and specifically can be 1:2.

[0036] And / or, the temperature of the addition reaction can be 60-90°C, and specifically can be 80°C.

[0037] And / or, the reaction time can be 4-12 hours, and specifically can be 7 hours.

[0038] And / or, the addition reaction is carried out under an inert atmosphere, such as a nitrogen atmosphere.

[0039] And / or, a basic catalyst, such as piperidine, needs to be added to the addition reaction.

[0040] And / or, the addition reaction is carried out in a solvent; preferably, the solvent can be a mixed solvent of dichloromethane and anhydrous ethanol, and the volume ratio of dichloromethane and anhydrous ethanol is preferably (0-4):50.

[0041] The present application also provides a nanoparticle, which is assembled from the compound of formula (I) described above.

[0042] According to the embodiments of the present application, the size of the nanoparticle can be nanoscale. Preferably, the size of the nanoparticle is 10-20 nm.

[0043] According to the embodiments of the present application, the nanoparticle is prepared by formulating a solution of the compound of formula (I), i.e. obtaining the nanoparticle; preferably, in the solution, the concentration of the compound of formula (I) can be 0.5 μM-100 μM, such as 1 μM, 2 μM, 5 μM, 10 μM, 15 μM, 20 μM, 25 μM, 30 μM, 40 μM, 50 μM, 60 μM, 70 μM, 80 μM, 100 μM. Preferably, in the solution, the solvent can be any one, two or more of water and phosphate buffer. According to the embodiments of the present application, the hydration kinetic diameter of the nanoparticle is 30 nm-200 nm, preferably 50 nm-150 nm, such as 60 nm, 70 nm, 75.8 nm, 80 nm, 88.8 nm, 90 nm, 98.6 nm, 100 nm.

[0044] The present application also provides the use of the compound of formula (I) described above or the nanoparticle described above in the preparation of an antibacterial agent.

[0045] According to an embodiment of the present application, the antibacterial agent is an agent or preparation against bacteria.

[0046] The present application also provides use of the compound of formula (I) or the nanoparticle in preparation of a cell membrane disruption agent.

[0047] According to an embodiment of the present application, the cell membrane disruption agent is a bacterial cell membrane disruption agent.

[0048] According to an embodiment of the present application, the bacteria can be gram-positive bacteria or gram-negative bacteria. Preferably, the gram-positive bacteria can be Staphylococcus aureus; preferably, the gram-negative bacteria can be Escherichia coli.

[0049] The present application also provides an antibacterial agent or a cell membrane disruption agent, the active ingredient of which is the compound of formula (I) or the nanoparticle.

[0050] According to an embodiment of the present application, the antibacterial agent is a photodynamic antibacterial agent. According to an embodiment of the present application, the antibacterial agent is an agent or preparation against bacteria.

[0051] According to an embodiment of the present application, the cell membrane disruption agent is a bacterial cell membrane disruption agent.

[0052] According to an embodiment of the present application, the bacteria can be gram-positive bacteria or gram-negative bacteria. Preferably, the gram-positive bacteria can be Staphylococcus aureus; preferably, the gram-negative bacteria can be Escherichia coli.

[0053] Advantages

[0054] The D-π-A structure of the organic conjugated molecule of formula (I) provided by the present application has strong photosensitization effect, and can generate active oxygen under white light irradiation, causing oxidative damage to bacteria, and further leading to the destruction of the membrane structure of bacteria and the death of bacteria. In addition, by adjusting the rigidity and flexibility of the conjugated unit of the acceptor part, the ability of the active oxygen generated by photosensitization can be controlled, and the binding strength with bacteria can be controlled, thereby affecting the killing effect on bacteria.

[0055] The present application provides a novel organic conjugated molecule, the long conjugated D-π-A structure of which makes the organic conjugated molecule more likely to form nanoparticles with high positive charge density, and a large amount of active oxygen generated under white light irradiation can efficiently lyse bacterial cell membranes, slowing down the generation of bacterial drug resistance. The organic conjugated molecule of formula (I) has strong photodynamic killing effect on gram-negative bacteria and gram-positive bacteria, has low hemolysis rate, and has good biocompatibility. The present application provides guidance for the development of efficient and low-toxic photodynamic antibacterial agents.

[0056] Definitions and explanations of terms

[0057] Unless otherwise indicated, the definitions of groups and terms in the present application specification and claims, including the definitions of examples, illustrative definitions, preferred definitions, definitions in tables, definitions of specific compounds in examples, etc., can be combined and coupled with each other in any manner. The group definitions and compound structures after such combination and coupling should be understood as within the scope of the present application specification and / or claims.

[0058] The term "C6-20aryl" is to be understood as meaning a monovalent aromatic or partially aromatic monocyclic, bicyclic or tricyclic hydrocarbon ring having 6 to 20 carbon atoms, preferably "C6-16aryl". The term "C6-16aryl" is to be understood as preferably meaning a monovalent aromatic or partially aromatic monocyclic, bicyclic or tricyclic hydrocarbon ring having 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or 16 carbon atoms, in particular a ring having 6 carbon atoms ("C6aryl"), such as phenyl; or a ring having 9 carbon atoms ("C9aryl"), such as indanyl or indenyl; or a ring having 10 carbon atoms ("C10aryl"), such as tetrahydronaphthyl, dihydronaphthyl or naphthyl; or a ring having 13 carbon atoms ("C13aryl"), such as fluorenyl; or a ring having 14 carbon atoms ("C14aryl"), such as anthryl.

[0059] The term "5-20 membered heteroaryl" is to be understood as including a monovalent monocyclic, bicyclic or tricyclic aromatic ring system, including aromatic or partially aromatic, having 5 to 20 ring atoms and comprising 1 to 5 heteroatoms independently selected from N, O and S, such as "5-16 membered heteroaryl". The term "5-16 membered heteroaryl" is to be understood as including a monovalent monocyclic, bicyclic or tricyclic aromatic ring system having 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 or 16 ring atoms, in particular 5 or 6 or 9 or 10 carbon atoms, and comprising 1 to 5, preferably 1 to 3, heteroatoms independently selected from N, O and S and, in each case additionally, can be benzo-fused. In particular, the heteroaryl is selected from thienyl, furanyl, pyrrolyl, oxazolyl, thiazolyl, imidazolyl, pyrazolyl, isoxazolyl, isothiazolyl, oxadiazolyl, triazolyl, thiadiazolyl, thia-4H-pyrazolyl and the like and their benzo derivatives, such as benzofuranyl, benzothienyl, benzoxazolyl, benzisoxazolyl, benzimidazolyl, benzotriazolyl, indazolyl, indolyl, isoindolyl and the like; or pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, triazinyl and the like and their benzo derivatives, such as quinolinyl, quinazolinyl, isoquinolinyl and the like; or azocinyl, indolizinyl, purinyl and the like and their benzo derivatives; or cinnolinyl, phthalazinyl, quinazolinyl, quinoxalinyl, naphthyridinyl, pteridinyl, carbazolyl, acridinyl, phenoxazinyl, phenothiazinyl, phenoxazinyl and the like. BRIEF DESCRIPTION OF DRAWINGS

[0060] Figure 1 Synthetic route of organic conjugated molecule shown in formula (I-A) in Example 1;

[0061] Figure 2 Synthetic route of organic conjugated molecule shown in formula (I-B) in Example 1;

[0062] Figure 3 Synthetic route of organic conjugated molecule shown in formula (I-C) in Example 1;

[0063] Figure 4 Hydrodynamic diameter distribution of nanoparticles assembled by organic conjugated molecules in Example 2;

[0064] Figure 5 Zeta potential data of nanoparticles assembled by organic conjugated molecules in Example 2;

[0065] Figure 6 TEM image of nanoparticles assembled by organic conjugated molecules in Example 2;

[0066] Figure 7 UV-Vis absorption spectrum of organic conjugated molecule solution in Example 2;

[0067] Figure 8 Fluorescence emission spectrum of organic conjugated molecule solution in Example 2;

[0068] Figure 9 Total active oxygen amount generated by organic conjugated molecule solution under white light irradiation in Example 3;

[0069] Figure 10 Active oxygen species generated by organic conjugated molecule solution under white light irradiation in Example 3;

[0070] Figure 11 Bactericidal effect of organic conjugated molecule on E. coli in Example 4;

[0071] Figure 12 Effect of organic conjugated molecule on surface charge of E. coli in Example 5;

[0072] Figure 13 Effect of organic conjugated molecule on surface morphology of E. coli in Example 5;

[0073] Figure 14 Bactericidal effect of organic conjugated molecule on S. aureus in Example 6;

[0074] Figure 15 Hemolytic property of organic conjugated molecule in Example 7. DETAILED DESCRIPTION

[0075] The technical solutions of the present application will be further described in detail below in combination with specific examples. It should be understood that the following examples are only illustratively described and explained the present application, and should not be interpreted as limiting the scope of protection of the present application. Any technology realized based on the above description of the present application is covered within the scope of the present application.

[0076] The experimental methods used in the following examples are conventional methods unless otherwise specified.

[0077] The materials, reagents, etc. used in the following examples, unless otherwise specified, can be obtained commercially.

[0078] PBS is a product with the item number SH30256.01 purchased from Hyclone.

[0079] E. coli (TOP10) was purchased from Tiangen Biochemical Technology (Beijing) Co., Ltd.

[0080] Staphylococcus aureus ATCC 6538 was purchased from China General Microbiological Culture Collection Center (CGMCC).

[0081] Electron microscopy imaging was performed on a scanning electron microscope (purchased from Hitachi, model S-4800).

[0082] The size and charge of the nanoparticles were detected using a Malven Zetasizer Nano-ZS instrument (ZEN 3600, Malven Instruments, Worcestershire, UK).

[0083] The remaining chemical and biological reagents were commercially available.

[0084] Example 1, synthesis of organic conjugated molecules

[0085] I. Synthesis of organic conjugated molecules represented by formula I-A (abbreviated as Cz-Ph-Ph-Hcy)

[0086]

[0087] According to the route map shown below, the organic conjugated molecules represented by formula I-A were synthesized, and the specific steps are as follows: Figure 1

[0088] ​(1) In a single-neck flask, 50 ml of anhydrous ethanol was added, and then 4-methylpyridine (9.80 mL, 0.100 mol) and 1,4-dibromobutane (4.3620 g, 0.0202 mol) were added to the reaction flask. The reaction was heated to reflux at 85°C for 10 hours. Extraction, anhydrous magnesium sulfate drying, filtration, rotary evaporation, dissolution, recrystallization, and drying were sequentially performed to obtain 1,1-(butane-1,4-diyl)bis(4-methylpyridine) bromide. The structure verification data are as follows: 1 H NMR (400 MHz): δ 1.97 (t, 4H), δ 2.45 (s, 6H), δ 5.01 (t, 4H), δ 7.67 (d, 4H), δ 8.90 (d, 4H).

[0089] (2) Under nitrogen protection, 9-(4-bromophenyl)carbazole (0.4004 g, 1.243 mmol), 4-formylphenylboronic acid (0.1863 g, 1.243 mmol), tetraphenylphosphonium palladium (0.1145 g, 0.0991 mmol), and potassium carbonate (0.1718 g, 1.243 mmol) were added to the reaction flask, respectively. Then, 20 mL of tetrahydrofuran and 5 mL of deionized water were bubbled in a 50 mL single-neck flask for half an hour to remove oxygen, and then the solvent was transferred to a 50 mL double-neck flask, the device was sealed, and the reaction was carried out under nitrogen protection at 80°C. TLC was used to track the progress of the reaction, and the reaction was completed after 8 hours. After cooling to room temperature, the reaction solution was extracted with ethyl acetate, dried with anhydrous magnesium sulfate, filtered, and rotary evaporated. Column chromatography was performed to obtain a biphenyl aldehyde containing a carbazole unit. The structure verification data are as follows: 1 H NMR (400 MHz): δ 7.16-7.20 (m, 2H), δ 7.35 (t, 1H), δ 7.50 (t, 1H), δ 7.58 (d, 1H), δ 7.83 (d, 1H), δ 7.90-8.00 (m, 5H), δ 8.04 (d, 2H), δ 8.19 (d, 2H), δ 8.55 (d, 1H), δ 9.89 (d, 1H).

[0090] (3) Under nitrogen protection, biphenylaldehyde (0.2500 g, 0.7199 mmol) containing a carbazole moiety was added, and then 50 mL of anhydrous ethanol was directly added to a two-necked flask. The temperature was raised to 80 ° C, 4 mL of dichloromethane was added, and then 1-(butane-1,4-diyl)bis(4-methylpyridinium) bromide (0.1424 g, 0.3542 mmol) and 15 drops of piperidine were added in sequence. The reaction apparatus was then sealed. After half an hour, the solution was found to be completely dissolved and dark red. After continuing the reaction for 20 minutes, an orange-red solid began to precipitate. The reaction was terminated after 7 hours. It was found that there was obvious solid-liquid separation. The yellow solid in the lower layer was filtered and recrystallized from anhydrous ethanol to obtain the organic conjugated molecule shown in Formula Ⅰ-A (abbreviated as Cz-Ph-Ph-Hcy). The structural verification data are as follows: 1 H NMR (400MHz): δ1.99 (t, 4H), δ4.59 (t, 4H), δ7.32 (m, 4H), δ7.47 (m, 8H), δ7.64 (m, 2H), δ7 .79 (m, 2H), δ7.88-7.98 (m, 10H), δ8.00-8.15 (m, 6H), δ8.27-8.32 (m, 8H), δ9.00 (m, 4H).

[0091] 2. Synthesis of the organic conjugated molecule represented by formula I-B (abbreviated as Cz-Ph-T-Hcy)

[0092]

[0093] according to Figure 2 The organic conjugated molecule represented by formula I-B is synthesized according to the route shown in the figure. The specific steps are as follows:

[0094] (1) 4-Methylpyridine and 1,4-dibromobutane generate 1,1-(butane-1,4-diyl)bis(4-methylpyridine)bromide, and the specific steps are the same as (1).

[0095] (2) Under nitrogen protection, 9-(4-bromophenyl)carbazole (0.4005 g, 1.243 mmol), 5-formyl-2-thiopheneboronic acid (0.1937 g, 1.242 mmol), tetrakistriphenylphosphine palladium (0.1156 g, 0.1000 mmol), and potassium carbonate (0.1715 g, 1.241 mmol) were added to the reaction flask. Then, 20 mL of tetrahydrofuran and 5 mL of deionized water were added to a 50 mL single-necked bottle and bubbled for deoxygenation for half an hour. The solvent was then transferred to a 50 mL double-necked bottle and refluxed at 80°C. The reaction progress was tracked by TLC. After 8 hours, the reaction was completed. After cooling to room temperature, the reaction solution was extracted with ethyl acetate, dried over anhydrous magnesium sulfate, filtered, and separated by column chromatography after rotary evaporation to obtain thiophene aldehyde containing a carbazole moiety. The structural verification data are as follows: 1H NMR (400 MHz): δ 7.10-7.20 (m, 2H), δ 7.35 (t, 1H), δ 7.50 (t, 1H), δ 7.58 (d, 1H), δ 7.80 (d, 1H), δ 7.90-8.00 (m, 6H), δ 8.19 (d, 1H), δ 8.55 (d, 1H), δ 9.84 (d, 1H).

[0096] (3) Under nitrogen protection, the thienyl aldehyde containing carbazole group (0.2502 g, 0.7082 mmol) was added, then 50 mL of anhydrous ethanol was measured and directly added into the flask, and the temperature was raised to 80°C, 2 mL of dichloromethane was added, then 1-(butane-1,4-diyl)bis(4-methylpyridine) bromide (0.1424 g, 0.3542 mmol) was added, 15 drops of piperidine was added, then the reaction device was sealed, half an hour later, it was found that the solution was completely dissolved and turned into a deep red color, after 20 minutes of continuous reaction, orange-red solid began to precipitate, after 7h, the reaction was completed, and obvious solid-liquid separation was observed, filtration was performed, and the lower layer orange-red solid was obtained, and anhydrous ethanol recrystallization was performed to obtain the organic conjugated molecule represented by formula I-B (abbreviated as Cz-Ph-T-Hcy). The structure verification data are as follows: 1 H NMR (400 MHz): δ 1.97 (t, 4H), δ 4.57 (t, 4H), δ 7.25 (m, 4H), δ 7.34 (m, 6H), δ 7.46 (m, 2H), δ 7.48 (m, 2H), δ 7.62 (m, 2H), δ 7.80 (m, 6H), δ 8.00 (m, 4H), δ 8.26-8.32 (m, 10H), δ 8.95 (m, 4H).

[0097] III. Synthesis of the organic conjugated molecule represented by formula I-C (abbreviated as DPA-Ph-T-Hcy)

[0098]

[0099] According to the route map shown in Figure 3 , the organic conjugated molecule represented by formula I-C was synthesized, and the specific steps were as follows:

[0100] (1) 4-methylpyridine and 1,4-dibromobutane were reacted to generate 1,1-(butane-1,4-diyl)bis(4-methylpyridine) bromide, and the specific steps were the same as (1).

[0101] (2) Under nitrogen protection, 4-bromotriphenylamine (1.2212 g, 3.769 mmol), 5-formyl-2-thiopheneboronic acid (0.4901 g, 3.141 mmol), tetrakis triphenylphosphine palladium (0.1815 g, 0.1571 mmol), potassium carbonate (1.3024 g, 9.424 mmol) were added into the reaction bottle respectively. Then 40 mL of tetrahydrofuran and 10 mL of deionized water were added, and the nitrogen was deoxidized for half an hour. Then it was sealed and heated in an oil bath at 80°C for 5 hours. Ethyl acetate extraction, anhydrous magnesium sulfate drying, filtration, rotary evaporation, and column chromatography separation were carried out to obtain a thiophene aldehyde containing a diphenylamine unit. The structure verification data are as follows: 1 H NMR (400 MHz): δ 7.16-7.20 (m, 2H), δ 7.34 (t, 1H), δ 7.48 (t, 1H), δ 7.58 (d, 1H), δ 7.80 (d, 1H), δ 7.90-8.00 (m, 7H), δ 8.19 (d, 1H), δ 8.55 (d, 1H), δ 9.84 (d, 1H).

[0102] (3) Under nitrogen protection, a thiophene aldehyde containing a diphenylamine unit (0.3553 g, 1.001 mmol) was added, and then 25 mL of anhydrous ethanol was directly added into a two-neck flask, which was heated to 80°C, and then 1-(butane-1,4-diyl)bis(4-methylpyridine) bromide (0.2011 g, 0.5002 mmol) and piperidine 1 mL were added in sequence. Then the reaction device was sealed and refluxed for 7 hours. It was found that there was obvious solid-liquid layering phenomenon. Filtration was carried out to obtain a red solid in the lower layer. Anhydrous ethanol recrystallization was carried out to obtain an organic conjugated molecule shown in formula I-C (abbreviated as DPA-Ph-T-Hcy). The structure verification data are as follows: 1 H NMR (400 MHz): δ 2.00 (t, 4H), δ 4.57 (t, 4H), δ 7.32 (m, 12H), δ 7.47 (m, 8H), δ 7.64 (m, 2H), δ 7.78 (m, 8H), δ 7.80 (m, 4H), δ 8.00-8.15 (m, 6H), δ 9.00 (m, 4H).

[0103] Example 2, Preparation of Organic Conjugated Molecule Nanoparticles and Characterization of Their Optical Physical Properties

[0104] (1) Preparation of Organic Conjugated Molecule Nanoparticles

[0105] Cz-Ph-Ph-Hcy, Cz-Ph-T-Hcy and DPA-Ph-T-Hcy solid powder prepared in Example 1 were dissolved with DMSO to prepare 5 mM stock solution, which was stored in 4 ℃ refrigerator in dark for later use. Before use, it was diluted to 25 μM with ultrapure water. The three organic conjugated molecules have amphiphilic property, and can form nanoparticles by self-assembly in aqueous solution.

[0106] (2) Nanoparticle size and surface charge

[0107] The particle size distribution and surface charge of the nanoparticles were measured by Malvern nanoparticle size analyzer. In the experiment, 4 mW He-Ne laser (λ = 632.8 nm) was used as light source: the data of backscattering light intensity were processed by Contin method to obtain the nanoparticle size distribution as shown in Figure 4 ; the electrophoretic light scattering data were collected, and the zeta potential of the nanoparticles was calculated by Helmholtz-Smoluchowski relationship, and the average of three results was calculated as the zeta potential of the nanoparticles as shown in Figure 5 . At the same time, 5 μL of 25 μM aqueous solution of the organic conjugated molecules was dropped onto an ultrathin carbon grid, and the morphology of the nanoparticles was observed by JEOL 2100F transmission electron microscope after natural air drying, and the results are shown in Figure 6 .

[0108] As can be seen from Figure 4 , the hydration kinetic diameters of the nanoparticles formed by Cz-Ph-Ph-Hcy, Cz-Ph-T-Hcy and DPA-Ph-T-Hcy in aqueous solution are 88.8, 75.8 and 98.6 nm, respectively. That is, with the increasing flexibility of the conjugated structure, the size of the nanoparticles first decreases and then increases. As can be seen from Figure 5 , it can be determined that the surface charge of the nanoparticles formed by the three organic conjugated molecules is greater than 70 mV, which provides a guarantee for the subsequent electrostatic binding of bacteria. As can be seen from the transmission electron microscope photos Figure 6 , the three organic conjugated molecules form spherical nanoparticles of 10-20 nm.

[0109] (3) Characterization of photophysical properties

[0110] Subsequently, the ultraviolet-visible absorption spectrometer and the fluorescence spectrophotometer were used to characterize the ultraviolet-visible absorption spectrum and the fluorescence emission spectrum of the three organic conjugated molecules, respectively. The organic conjugated molecules were scanned at 200-800 nm, and the wavelength corresponding to the maximum absorption peak was selected as the excitation wavelength of the fluorescence spectrum, and the fluorescence emission spectrum of the organic conjugated molecules was scanned.

[0111] As can be seen from Figure 7It can be seen that the three kinds of organic conjugated molecules have strong light absorption ability in the near ultraviolet and visible light region (320-650 nm), which provides a basis for the subsequent selection of white light as a light source to produce active oxygen. The maximum ultraviolet absorption wavelengths of Cz-Ph-Ph-Hcy, Cz-Ph-T-Hcy and DPA-Ph-T-Hcy are 385 nm, 435 nm and 470 nm, respectively. As shown in Figure 8 , the three kinds of organic conjugated molecules all have good fluorescence emission ability, and the maximum fluorescence emission wavelengths are 575 nm, 605 nm and 634 nm, respectively. Because the three kinds of organic conjugated molecules all have a large stoke shift (>160 nm), they can be used for fluorescence imaging to characterize the combination of the three kinds of organic conjugated molecules with bacteria.

[0112] Example 3, evaluation of the photodynamic activity of the compound represented by formula I

[0113] Under visible light irradiation, the ability of the three kinds of organic conjugated molecules to generate active oxygen was detected by 2,7-dichlorofluorescein diacetate (DCFH-DA) probe. A 10 mM DCFH-DA solution was prepared and placed in a refrigerator at -20°C for standby. Before the experiment, ethanol and 0.01M NaOH aqueous solution were added to the 10 mM DCFH-DA stock solution, and the mixture was activated at room temperature for 30 min in the dark to obtain an activated solution. The activated solution was diluted with 1×PBS to obtain a DCFH working solution with a final concentration of 40 μM. It was placed on ice and protected from light. The amount of ROS generated was determined by testing the fluorescence emission intensity at 525 nm. Figure 9 Then, singlet oxygen green fluorescence probe (SOSG), dihydroethidium (DHE) and hydroxyphenyl fluorescein (HPF) were used as indicators to monitor the generation of 1 O2, ·O2 - and ·OH by the three kinds of organic conjugated molecules under visible light irradiation. 0.5 μM organic conjugated molecule solution was mixed with SOSG, DHE and HPF, respectively, and irradiated under visible light for 10 min. The probe solution without the addition of organic conjugated molecules was used as a blank group. By determining the change of fluorescence intensity with light irradiation time, the generation amount of 1 O2, ·O2 - and ·OH was determined. Figure 10

[0114] As shown in Figure 9 , under low light intensity (5 mW·cm -2 ​The blank group DCFH fluorescence signal intensity increased substantially unchanged with time, while the fluorescence intensity of the three low concentrations (0.5 μM) of organic conjugated molecules Cz-Ph-Ph-Hcy, Cz-Ph-T-Hcy and DPA-Ph-T-Hcy at 525 nm increased significantly with the increase of irradiation time, which showed that the designed and synthesized organic conjugated molecules had excellent photodynamic properties and could produce a large amount of ROS to kill bacteria in a short time.

[0115] It can be seen from Figure 10 that the active oxygen produced by the three organic conjugated molecules under white light irradiation can oxidize the ·OH probe to emit fluorescence signals, and the fluorescence signals gradually increase with time. However, the generated active oxygen cannot oxidize the ·O2 - probe to emit fluorescence, and only a small amount of ·O2 1 probe can emit fluorescence. These results show that the three organic conjugated molecules mainly produce active oxygen through the low-oxygen-dependent Type-I pathway, and a small amount of ROS is generated through the aerobic Type-II pathway.

[0116] Example 4, photodynamic killing effect of the compound represented by formula I on E. coli

[0117] Agar plate counting method was used to characterize the killing effect of organic conjugated molecules on E. coli: 100 μL of Amp 600 coli liquid with OD r = 1.0 was added to 400 μL of organic conjugated molecule PBS solution, and the concentration of organic conjugated molecules in the reaction liquid was 0, 0.5, 5, 10, and 25 μM, respectively. Then the mixed reaction liquid was placed in a 37°C incubator for 30 min in the dark. The subsequent antibacterial experiment was set up with light and dark groups, and the light group was irradiated for 10 min under white light (65 mW·cm -2 ), and the dark group was wrapped with tin foil and stored for 10 min. The treated bacterial liquid was diluted 1×10 4 times with 1×PBS, 100 μL of which was uniformly coated on the LB medium, which was cultured at 37°C for 16-18 h, and the number of colonies formed was recorded. The antibacterial rate IR of the organic conjugated molecules on Amp r coli was calculated by the formula IR = (C-C0) / C0×100%, where C is the colony forming unit number (CFU) of the experimental group, and C0is the colony forming unit number of the control group. Each group of experiments was repeated three times, and the average value was taken.

[0118] It can be seen from Figure 11 that for gram-negative bacteria (Amp rE. coli), all three organic conjugated molecules showed certain degree of dark toxicity, and their dark toxicity gradually increased with the increase of concentration. Under visible light irradiation, Cz-Ph-Ph-Hcy, Cz-Ph-T-Hcy and DPA-Ph-T-Hcy showed excellent photodynamic antibacterial effect on Amp r coli. The bactericidal rates of the three organic conjugated molecules at 25 μM under light irradiation were 100%, 100% and 95.57%, respectively. These results showed that the three organic conjugated molecules had excellent photodynamic antibacterial effect on gram-negative bacteria. r coli. The bactericidal rates of the three organic conjugated molecules at 25 μM under light irradiation were 100%, 100% and 95.57%, respectively. These results showed that the three organic conjugated molecules had excellent photodynamic antibacterial effect on gram-negative bacteria.

[0119] Example 5, Mechanism of the compound of formula I on E. coli

[0120] Firstly, the change of surface Zeta potential of E. coli after incubation with organic conjugated molecules was determined by using nanoparticle size potential instrument. The specific steps were as follows: 100 μL of bacterial solution (OD600=1.0), organic conjugated molecule Cz-Ph-Ph-Hcy, Cz-Ph-T-Hcy and TPA-T-Hcy stock solution and appropriate amount of 1 × PBS were mixed to a total volume of 500 μL, and the final concentration of organic conjugated molecules was 5, 10, 15 and 20 μM, respectively. Then, the mixture was incubated in 37 °C culture for 30 min in the dark. After incubation, the supernatant was removed by centrifugation, 1 ml of sterile water was added and mixed, and then the mixture was placed on ice for measurement. The measurement results are shown in Figure 12 Then, the change of surface morphology of E. coli after treatment with organic conjugated molecules was characterized by SEM. According to the steps of "plate antibacterial experiment", the organic conjugated molecules were co-incubated with E. coli, and then treated in the dark or under light irradiation. The treated bacterial solution was centrifuged at 7100 rpm for 10 min, and then 2.5% glutaraldehyde was added to fix the bacteria in a refrigerator at 4 °C overnight. After removing the glutaraldehyde by centrifugation, the bacterial solution was washed twice with 1 × PBS. Finally, 5 μL of the bacterial solution was taken onto a clean silicon wafer, and then the wafer was naturally air-dried in a clean bench. After the sample was dried, the sample was gradient dehydrated with 40%, 70%, 90% and 100% ethanol for 6 min each time. After natural drying of the sample at room temperature, the sample was subjected to gold spraying treatment and SEM imaging. The changes of surface morphology of E. coli are shown in Figure 13

[0121] As can be seen from Figure 12 , the organic conjugated molecules can be electrostatically combined to the negatively charged bacterial surface. Figure 13 ​The effect of organic conjugated molecules on E. coli was directly reflected. Under dark conditions, the E. coli in the blank group had a plump morphology, intact structure, and relatively uniform size. Under light conditions, the surface of the bacteria treated with organic conjugated molecules showed severe shrinkage, collapse, and overflow of contents. Combining the zeta potential and SEM results, the possible antibacterial mechanism of organic conjugated molecules was analyzed as first binding to the bacterial surface through electrostatic interaction, and then generating ROS under light conditions, destroying the bacterial components such as DNA, proteins, and lipids. As a result, the integrity of the bacterial membrane was severely damaged, the contents continued to overflow, and ultimately led to the death of the bacteria.

[0122] Example 6: Photodynamic Killing Effect of the Compound of Formula I on Staphylococcus aureus

[0123] The same agar plate counting method was used to characterize the killing effect of organic conjugate molecules on Staphylococcus aureus: 100 μL of OD 600 =1.0 was added to 400 μL of organic conjugate molecule PBS solution to make the organic conjugate molecule concentration in the solution 0, 1, 2, 5, 10, and 15 μM, and then placed in a 37°C incubator in the dark for 30 minutes. The subsequent antibacterial experiment was set up in two groups: light and dark. The light group was exposed to white light (65 mW·cm -2 ) for 10 min, and the dark group was wrapped with tin foil and stored for 10 min. The treated bacterial solution was diluted with 1× PBS to 1×10 4 100 μL was evenly spread on NB medium and incubated at 37°C for 16-18 hours. The number of colonies formed was recorded. The inhibitory rate (IR) of the organic conjugate molecule against S. aureus was calculated using the formula IR = (C - C0) / C0 × 100%, where C is the colony-forming unit (CFU) of the experimental group and C0 is the CFU of the control group. Each experiment was repeated three times, and the average value was calculated.

[0124] Depend on Figure 14 It can be seen that for Gram-positive bacteria (S. aureus), the three organic conjugated molecules all have high dark toxicity, and the dark toxicity gradually increases with the increase of the concentration of organic conjugated molecules. The bactericidal rates of 15μM Cz-Ph-Ph-Hcy, Cz-Ph-T-Hcy and DPA-Ph-T-Hcy against S. aureus were 79.8%, 82.2% and 58.7% respectively. After the introduction of white light irradiation, the antibacterial activity of the three organic conjugated molecules against S. aureus reached 100%. These results show that the three organic conjugated molecules are mainly antibacterial against Gram-positive bacteria through cationic membrane disruption, and have excellent photodynamic antibacterial effects.

[0125] Example 7: Good biocompatibility of the compound represented by Formula I

[0126] The biological safety of the organic conjugated molecules was characterized by determining their hemolysis rate. The specific steps were as follows: an equal amount of fresh rabbit blood was centrifuged to remove the supernatant to obtain sufficient red blood cells. Different concentrations of three organic conjugated molecules were incubated with diluted red blood cells at 37°C for 3h. Finally, the supernatant was centrifuged to measure the absorbance and calculate the hemolysis rate. The red blood cells incubated with Triton X100 were the positive control group PC, and the red blood cells incubated with normal saline were the negative control group NC.

[0127] In the hemolysis experiment ( Figure 15 ), compared with the positive control group (Triton X100), even if the concentration of the three organic conjugated molecules was as high as 100 μM, the hemolysis rate of the red blood cells was still much lower than 5%. The lower hemolysis of the three organic conjugated molecules indicated that they had good biological safety.

[0128] The above describes the embodiments of the present application. However, the present application is not limited to the above-described embodiments. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. An organic conjugated molecular compound, having a structural formula as shown in formula (I), ###0001### (I) wherein, n is an integer selected from 2-12; X is halogen; and n is an integer selected from 3-10. wherein 2. The compound of claim 1, wherein, n is an integer selected from 2-12; X is F.

3. The compound of claim 1, wherein, n is an integer selected from 2-12; X is Cl. selected from C6-10 aryl, 5-10 membered heteroaryl; selected from carbazole, diphenylamine.

2. The compound of claim 1, wherein 4. The compound of any one of claims 1-3, wherein, n is an integer selected from 2-12; X is Br.

3. The compound of claim 1, wherein 6. The compound of any one of claims 1-3, wherein, the compound is selected from any one of the following formula (I-A), formula (I-B), formula (I-C): ###0002### (I-A) (I-B) (I-C) wherein, n is an integer selected from 2-12; X is Br.

8. A method for preparing the compound of formula (I) of any one of claims 1-7, comprising the following steps: (1) substituting 4-methylpyridine with a compound of formula (II) to obtain a compound of formula (III); ###0003### (II) (III) wherein, X, n have the definitions of any one of claims 1-7; (2) coupling a compound of formula (IV) with a compound of formula (V) to obtain a compound of formula (VI); ###0004### (IV) (V) (VI) wherein, X, n have the definitions of any one of claims 1-7; (3) adding a compound of formula (III) with a compound of formula (VI) to obtain a compound of formula (I). selected from: phenyl, naphthyl, thienyl, furanyl.

5. The compound of claim 4, wherein selected from indicates the point of attachment of the radical.

9. A nanoparticle, which is assembled from the compound of formula (I) of any one of claims 1-7. selected from indicates the point of attachment of the group.

7. The compound of any one of claims 1-3, wherein The size of the nanoparticle is 10-20 nm.

11. Any one of the following applications of the compound of formula (I) of any one of claims 1-7, or the nanoparticle of any one of claims 9-10: (i) application in preparing an antibacterial agent; the antibacterial agent is an antibacterial reagent or preparation; (ii) application in preparing a cell membrane damaging reagent; the cell membrane damaging reagent is a bacterial cell membrane damaging reagent. The bacteria are gram-positive bacteria or gram-negative bacteria. wherein 13. An antibacterial agent or a cell membrane damaging reagent, whose active ingredient is the compound of formula (I) of any one of claims 1-7, or the nanoparticle of any one of claims 9-10; the antibacterial agent is an antibacterial reagent or preparation, or a photodynamic antibacterial agent; the cell membrane damaging reagent is a bacterial cell membrane damaging reagent. The bacteria are gram-positive bacteria or gram-negative bacteria. wherein X has the definition of any one of claims 1 to 7; ​ ​ 10. The nanoparticle of claim 9, wherein, ​ ​ ​ ​ 12. Use according to claim 11, characterized in that, ​ ​ ​ ​ 14. The antimicrobial or cell membrane disruptive agent of claim 13, wherein, ​

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