A fluorescent probe of an AIE molecule-modified cationic polymer and its preparation method and application

Abstract

The present invention discloses a fluorescent probe of an AIE molecule modified cationic polymer, and a preparation method and application thereof. The structure of the fluorescent probe consists of a polyamino cationic polymer A, an AIE photosensitizer B, and a hydrophobic component C; A and B, A and C are respectively connected by chemical bonds. The preparation method of the fluorescent probe of the present invention adopts an efficient alkynamine click reaction. The fluorescent probe of the present invention has aggregation-induced luminescence properties, avoids the ACQ effect of traditional fluorescent molecules, realizes the synchronous enhancement of fluorescence and ROS, and can realize rapid staining and identification of all living bacteria, reflecting efficient and sensitive characteristics. The fluorescent probe of the present invention has excellent photodynamic antibacterial effect and can achieve photodynamic killing of a variety of bacteria at low concentrations. The fluorescent probe of the present invention has a low degree of internalization, has a strong anchoring ability for cell membrane structure, and can also be used for long-term imaging of biomass membranes.

Description

Technical Field

[0001] The invention belongs to the technical field of biological fluorescent probes, and specifically relates to a fluorescent probe of an AIE molecule modified cationic polymer and a preparation method and application thereof. Background Art

[0002] Bacteria exist widely around us. Probiotics and we depend on each other to maintain the normal functioning of our body functions, while pathogenic bacteria seriously threaten human health, and the abuse of antibiotics has also led to the emergence of many super bacteria. In recent years, the infection rate of bacteria has increased year by year. In the process of clinical treatment of bacterial infections, the traditional Gram staining method as a diagnostic method is complicated to operate and cannot achieve in situ detection of live bacteria, and photodynamic antibacterial has also been proven not to cause bacterial resistance. Therefore, it is imperative to develop a broad-spectrum photodynamic antibacterial material that can quickly image and identify various bacteria and effectively kill them.

[0003] At present, fluorescent probes have been widely used in the fields of biological imaging and treatment. However, traditional fluorescent materials have the problem of aggregation-induced luminescence quenching (ACQ) in the aggregated state in the body, and traditional hydrophobic photosensitizers often face the problem of insufficient ROS production in the physiological environment. Therefore, fluorescent materials with aggregation-induced emission (AIE) properties have high luminescence efficiency and ROS generation efficiency in the aggregated state, which can greatly improve the sensitivity of detection and the photodynamic killing effect.

[0004] The present invention synthesizes a fluorescent material with AIE properties having good biomass membrane binding ability, and realizes rapid binding and staining of various bacteria by regulating the multi-component structure of the polymer, which can be used as a general method to solve the problem that most AIE photosensitizers cannot bind to Gram-negative bacteria (miao miao Kang, Cheng Cheng Zhou and Ben Zhong Tang, Evaluation of Structure-Function Relationships of Aggregation-Induced Emission Luminogens for Simultaneous Dual Applications of Specific Discrimination and Efficient Photodynamic Killing of Gram-Positive Bacteria, J. Am. Chem. Soc., 2019, 141, 16781-16789), and the preparation process is simple compared to other multifunctional fluorescent reagents, no post-processing is required, and long-term fluorescence imaging can also be achieved for biomass membranes, and the effect is far better than currently available commercial reagents. At the same time, because AIE gives the material excellent ROS production effect, it also realizes the broad-spectrum antibacterial effect of photodynamics for a variety of stubborn and resistant bacteria. Summary of the invention

[0005] In view of the deficiencies of the prior art, the object of the present invention is to provide a fluorescent probe of an AIE molecule modified cationic polymer. The fluorescent probe of the present invention is a functionalized post-modified polymer with aggregation-induced emission (AIE) properties. A multifunctional material is prepared by a one-pot reaction of multiple modules without complicated post-processing. It can achieve rapid binding to live bacteria and biomass membranes and achieve specific imaging of biomass membranes. The fluorescent probe of the present invention has an excellent antibacterial effect at extremely low concentrations of photosensitizers and is a broad-spectrum photodynamic antibacterial agent.

[0006] Another object of the present invention is to provide a method for preparing the fluorescent probe. The synthesis method of the present invention is simple, and adopts an efficient and convenient alkynylamine click reaction, and a multifunctional product can be obtained by feeding in a one-pot method without dialysis or separation and purification operations.

[0007] Another object of the present invention is to provide the application of the fluorescent probe, including the application as a photodynamic antibacterial agent and a bioplasma membrane imaging agent.

[0008] The fluorescent probe is used in biological imaging and is used as an imaging agent.

[0009] The fluorescent probe can also be used as a highly efficient photodynamic antibacterial agent to achieve rapid binding and killing of a variety of bacteria.

[0010] The fluorescent probe is used in long-term imaging of bioplasma membranes.

[0011] The purpose of the present invention is achieved through the following technical solutions:

[0012] A fluorescent probe of an AIE molecule modified cationic polymer, the structure of which is as follows:

[0013]

[0014] Among them, A is a polyamino cationic polymer, B is an AIE photosensitizer, and C is a hydrophobic component; A and B, A and C are connected by chemical bonds, respectively.

[0015] Preferably, the polyamino cationic polymer is at least one of polyethyleneimine, polypropyleneimine, polylysine, poly(β-amino ester), polyamide-amine dendrimer, polyamino ester, and chitosan;

[0016] Preferably, the molecular weight of the polyamino cationic polymer is 20,000-30,000.

[0017] Preferably, the AIE photosensitizer is an AIE photosensitizer with a carbonyl or ester activated alkyne structure at the end; further preferably, the AIE photosensitizer has a DAD structure.

[0018] Preferably, the hydrophobic component is a lipid molecule with a carbonyl or ester activated alkyne structure at the end.

[0019] Preferably, the AIE photosensitizer is MTPABP-pyo, and the structural formula is as follows:

[0020]

[0021] Preferably, the hydrophobic component is Chol-yne, and the structural formula is as follows:

[0022]

[0023] Preferably, the fluorescent probe exists in the form of nanoparticles in the aqueous solution.

[0024] The preparation method of the above-mentioned AIE molecule modified cationic polymer fluorescent probe comprises the following steps:

[0025] The AIE photosensitizer B and the hydrophobic component C dissolved in the organic solvent 1 are added to the solution of the polyamino cationic polymer A dissolved in the protic solvent 2, and reacted for 3-5 hours to obtain a fluorescent probe of the AIE molecule modified cationic polymer.

[0026] Preferably, the organic solvent 1 is tetrahydrofuran (THF); the protic solvent 2 is methanol;

[0027] Preferably, the step of adding the AIE photosensitizer B and the hydrophobic component C dissolved in the organic solvent 1 to the solution of the polyamino cationic polymer A dissolved in the protic solvent 2 is performed under ice bath conditions.

[0028] Preferably, the molar amount of the AIE photosensitizer B is 1%-3% of the molar amount of the amino groups in the polyamino cationic polymer A; the molar amount of the hydrophobic component C is 1%-3% of the molar amount of the amino groups in the polyamino cationic polymer A.

[0029] Preferably, the reaction temperature is room temperature.

[0030] A nanoparticle prepared by using the fluorescent probe of the cationic polymer modified by the above-mentioned AIE molecule.

[0031] The method for preparing the above-mentioned nanoparticles comprises the following steps:

[0032] The fluorescent probe of the AIE molecule-modified cationic polymer is dissolved in the organic solvent 3, and then added into ultrapure water and stirred until the organic solvent 3 is completely volatilized to obtain nanoparticles.

[0033] Preferably, the organic solvent 3 is THF; the mass volume ratio of the fluorescent probe of the AIE molecule modified cationic polymer, the organic solvent 3 and ultrapure water is 5-20 mg: 0.5-1 mL: 5-20 mL.

[0034] The application of the fluorescent probe of the AIE molecule modified cationic polymer and the nanoparticles in the preparation of cell imaging reagents, cell staining reagents and antibacterial reagents.

[0035] The fluorescent probe and nanoparticles are used to prepare fluorescent reagents for effective imaging of living bacteria; the imaging is fluorescent imaging of all living bacteria.

[0036] The fluorescent probe and nanoparticles are used to prepare a broad-spectrum photodynamic antibacterial agent effective against a variety of bacteria, including Gram-positive bacteria, Gram-negative bacteria and fungi.

[0037] The fluorescent probe and nanoparticles are used to prepare a specific staining reagent for biomass membranes, and the staining is selective fluorescence imaging of cell membranes / cell walls.

[0038] The fluorescent probe and nanoparticles are used to prepare a long-term staining reagent for cell membranes.

[0039] The reaction used to construct the material of the present invention is an alkynylamine click reaction, which can be used as a general method for synthesizing multi-module compounds. After the reaction is completed, no post-processing, dialysis, freeze-drying and other operations are required, and the reaction efficiency is 100%.

[0040] The material constructed by the present invention is mainly composed of a cationic polymer and modified with AIE molecules and cholesterol-activated alkyne molecules. The material utilizes the AIE characteristics of the molecules to enhance the luminescence and ROS of the fluorescent probe, and can also combine with bacteria or cells with negative charges on the surface through electrostatic adsorption, and can achieve efficient killing of bacteria when exposed to light.

[0041] The present invention solves the problem that most common small molecule AIE photosensitizers cannot effectively bind to Gram-negative bacteria. It has good live bacterial imaging effects on a variety of Gram-negative bacteria such as Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumoniae, and is a broad-spectrum photodynamic antibacterial agent.

[0042] The fluorescent reagent provided by the present invention can be used for imaging biomass membranes and for specific staining of cell membranes. It can stay on the cell membrane for a considerable period of time without being internalized by the cell and is not prone to photobleaching, so it can be used for long-term imaging and labeling of cell membranes.

[0043] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0044] (1) The present invention synthesizes a multi-component cationic polymer fluorescent material with aggregation-induced emission (AIE) properties. The synthesis method is simple, using a highly efficient alkynylamine click reaction, without the need to separate intermediates and without any post-treatment, and without the need for dialysis and other operations. A polymer material with a yield of 100% is obtained through a multi-component one-pot reaction.

[0045] (2) The fluorescent material described in the present invention can be combined with imaging of Gram-positive bacteria, Gram-negative bacteria and fungi, and effectively utilizes the AIE effect to enhance the luminescence intensity and ROS production rate of the fluorescent probe, and can achieve efficient photodynamic killing, and is a broad-spectrum antibacterial agent.

[0046] (3) The fluorescent material described in the present invention can achieve specific imaging of biomass membranes and can remain on the cell membrane for a long time, which has properties far superior to those of current commercial cell membrane staining reagents. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 The AIE curve of MTPABP-pyo of the present invention: As the H2O content increases, MTPABP-pyo (10 -5 M) Normalized fluorescence emission graph in THF / H2O (v / v) mixed solvent;

[0048] Figure 2 is a particle size distribution diagram of PEI-MTPABP-Chol nanoparticles of the present invention;

[0049] Figure 3 The number of luminescent units of MTPABP-pyo in the THF dispersion state and PEI-MTPABP-Chol nanoparticles in the aqueous solution aggregation state is the same (10 -5 M) fluorescence intensity comparison diagram;

[0050] Figure 4 The ROS generation capacity of the PEI-MTPABP-Chol nanoparticles of the present invention is: when the DCFH probe concentration is 5 μM, the polymer concentration is 5 μg / mL, and the illumination intensity is 20 mWcm -2 The ratio of the solution fluorescence intensity to the initial fluorescence intensity (I / I0) was plotted under the same conditions of the luminescence unit, with MTPABP-pyo as the reference and DCFH as the blank control;

[0051] Figure 5 Fluorescence imaging photos of the PEI-MTPABP-Chol nanoparticles of the present invention under a laser confocal microscope after incubation with Staphylococcus aureus, Escherichia coli and Candida albicans respectively;

[0052] Figure 6 PEI, PEI-MTPABP and PEI-MTPABP-Chol of the present invention were incubated with Escherichia coli (E. coli) at a concentration of 1 μg / mL for 20 min and then heated at 40 mW / cm -2 The results of the diluted agar plates after 20 min of white light irradiation, using PBS as the control group;

[0053] Figure 7 The PEI-MTPABP-Chol of the present invention was incubated with Staphylococcus aureus (S. aureus) at a concentration of 1 μg / mL for 20 min and then heated at 40 mW / cm -2 The results of the diluted agar plates after 20 min of white light irradiation, using PBS as the control group;

[0054] Figure 8 The PEI-MTPABP-Chol of the present invention was incubated with Candida albicans (C.albican) at a concentration of 4 μg / mL for 20 min and then heated at 40 mW / cm -2 The results of the diluted agar plates after 20 min of white light irradiation, using PBS as the control group;

[0055] Fig. 9CLSM images of the bioplasma membranes of fungi (C.albican) and cells (Hela) imaged by the PEI-MTPABP-Chol nanoparticles of the present invention;

[0056] Fig.10 The CLSM diagram of the internalization degree of the material by cells at different times under the condition of long-term incubation of PEI-MTPABP-Chol nanoparticles and Hela cells in the present invention. DETAILED DESCRIPTION

[0057] The present invention will be further described below in conjunction with specific embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0058] Example 1

[0059] A fluorescent probe (PEI-MTPABP-Chol) was prepared as follows:

[0060]

[0061] The MTPABP-pyo compound was prepared according to the method disclosed in the literature (Chen Chen Liu, Hao Tian Bai and Ben ZhongTang, Functionalization of Silk by AIEgens through Facile Bioconjugation: Full-Color Fluorescence and Long-Term Bioimaging, Angew. Chem. 2021, 133, 2-9.).

[0062] The synthetic route of Chol-yne compounds is as follows:

[0063]

[0064] Synthesis of Chol-yne: This experiment uses the Mitsunobu reaction (Mitsunobu reaction), which requires strict anhydrous and oxygen-free conditions. First, a 250mL double-mouthed round-bottomed flask equipped with a magnet is placed in a 120°C oven for half an hour to completely evaporate its water. Then, cholesterol (1.15g, 3mmol), propiolic acid (0.25g, 3.6mmol), and triphenylphosphine (0.95g, 3.6mmol) weighed in advance are added to the double-mouthed flask, and then the system is kept in a nitrogen atmosphere after vacuuming and filling with nitrogen three times. 80mL of dry redistilled THF is added to the reaction system as a solvent using a syringe, and an ice bath is added to stabilize the system at 0°C. Then, a quantitative amount of diethyl azodicarboxylate (0.63g, 3.6mmol) is slowly added dropwise to the system, and then reacted at room temperature for 12h. After most of the solvent in the reaction solution was rotary evaporated, it was extracted and washed with dichloromethane and saturated ammonium chloride solution, and then the product was separated and purified by column chromatography, using petroleum ether / DCM (10 / 1, v / v) as eluent to finally obtain a white solid (0.39 g, 30% yield). 1H NMR (400MHz, Chloroform-d) d=5.39(d, J=4.9Hz,1H),4.73(tdd, J=10.0,7.0,4.4Hz,1H),2.85(s,1H),2.39(dd, J=7.3,2.1Hz,2H),2.06–0.84(m,38H),0.68ppm(s,3H);13C NMR (125MHz, Chloroform-d): d=152.3,139.2,123.4,76.6,75.3,74.3,56.8,56.3,50.2,42.5,39.9,39.7,37.9,37.0, 36.7,36.3,35.9,32.1,32.0,28.4,28.2,27.7,24.4,24.0,23.0,22.7,21.2,19.4,18.9,12.0ppm; HRMS(EI):m / zcalcd for C30H46O2:438.3498[M]+; found:438.3489.

[0065] Synthesis of PEI-MTPABP-Chol: 20 mg of branched PEI (M W=25000) was dissolved in 1 mL of methanol and added to a strip reaction tube for stirring, and the system temperature was kept constant at 0°C in an ice bath. MTPABP-pyo (2.58 mg) and Chol-yne (2.00 mg) were dissolved in 0.5 mL of THF, and then the THF solutions of MTBPAB-pyo and Chol-yne were added dropwise to the reaction system in order. After the temperature rose to room temperature, the reaction was carried out at room temperature for 3 hours. Under this feed ratio, the grafting rate of AIE photosensitizer and cholesterol to the amino groups on PEI was 1%. After that, the solvent was dried with a hair dryer to obtain a red solid (24.5 mg, 100%), which was used as a precursor for preparing nanoparticles, i.e., a fluorescent probe.

[0066] Preparation of nanoparticles: PEI-MTPABP-Chol nanoparticles were prepared by nanoprecipitation method. 10 mg of dry PEI-MTPABP-Chol precursor was weighed into a 2 mL centrifuge tube, 0.5 mL of THF was added, and the solution was ultrasonicated in a room temperature water bath for 5 min using an ultrasonic cleaner. The solution was evenly dispersed at a frequency of 70 kHz. After the solution appeared red and transparent, it was transferred to a transparent glass bottle containing 5 mL of Milli-Q ultrapure water and stirred overnight until the THF was completely evaporated. The clear and transparent solution was the PEI-MTPABP-Chol nanoparticle solution, and its particle size was tested by DLS.

[0067] Example 2

[0068] Characterization of AIE Characteristics of PEI-MTPABP-Chol Fluorescence Probe

[0069] Figure 1 The fluorescence spectra of the material MTPABP-pyo obtained in Example 1 under different water content conditions are shown in Figure 1. When the photosensitizer molecules are in a tetrahydrofuran solution, the luminescence is weak. With the addition of water, it can be found that the fluorescence intensity is gradually increasing. This is because with the addition of poor solvent water, the molecular aggregation leads to enhanced fluorescence. This result shows the good aggregation-induced emission (AIE) properties of these molecules.

[0070] Figure 3 The figure shows a comparison of the fluorescence intensities of MTPABP-pyo and PEI-MTPABP-Chol obtained based on Example 1 in the dispersed state in THF solution and the aggregated state in aqueous solution when the number of luminescent units is the same. When the number of luminescent units is the same, it is obvious that PEI-MTPABP-Chol in the particle aggregated state has stronger fluorescence emission.

[0071] Example 3

[0072] Particle size characterization of PEI-MTPABP-Chol nanoparticles

[0073] Figure 2 The particle size distribution diagram of the nanoparticles obtained in Example 1 characterized by DLS is shown in Figure 1. The nanoparticles prepared by the method of Example 1 have uniform particle size distribution, small PDI, large potential, and good particle stability.

[0074] Example 4

[0075] Test of the Reactive Oxygen Generation Capacity of PEI-MTPABP-Chol Nanoparticles

[0076] The ROS generating capacity of the material obtained in Example 1 was tested using the probe DCFH for total ROS generating capacity testing, and compared with the ROS generating capacity of the small molecule MTPABP-pyo, with DCFH serving as a blank control. Figure 4 The ratio of the fluorescence intensity of the solution to the initial fluorescence intensity (I / I0) as the illumination time increases is used to measure the total ROS generation rate. As the illumination time increases, the ROS generated by the material also increases, and the ROS generation rate of PEI-MTPABP-Chol is greater than that of the small molecule MTPABP-pyo, indicating that the fluorescent probe has a better ROS generation ability than the small molecule under this test condition. This fluorescent probe significantly enhances the fluorescence and ROS generation by effectively utilizing the aggregation state.

[0077] Example 5

[0078] Staining effect of PEI-MTPABP-Chol nanoparticles on various bacteria

[0079] The results of staining and identification of various bacteria by PEI-MTPABP-Chol nanoparticles are shown in the figure. Figure 5 Among them, Staphylococcus aureus, Escherichia coli and fungi were respectively used as representatives of Gram-positive bacteria, Gram-negative bacteria and fungi. It was found that the nanoparticle fluorescent probe obtained in Example 1 can achieve rapid binding and imaging for a variety of bacteria.

[0080] Example 6

[0081] Antibacterial effect test of PEI-MTPABP-Chol nanoparticles

[0082] After washing three times with PBS, the bacterial solution was diluted to a concentration of 1 × 10 6 CFU / mL, and then co-cultured with PEI-MTPABP-Chol nanoparticles in PBS for 20 min. The experiment set up light group and dark group, and then used 40mWcm -2 The bacterial suspension of the illumination group was irradiated with white light for 20 min. Then the bacterial suspension was diluted to 5×10 3CFU / mL, take 100μL of the dilution and add it dropwise onto the solid agar plate, use an L-shaped spreading stick to spread it on the agar plate until the liquid is completely absorbed, invert it and place it in a constant temperature incubator at 37℃ for 16-24h. When the colonies on the agar plate grow to an appropriate size, take pictures and use a bacteria counter to count them.

[0083] In order to more conveniently study the effects of various components in the material on the material properties, PEI, PEI-MTPABP and the material PEI-MTPABP-Chol obtained in Example 1 were used as effect controls, wherein the preparation methods of PEI-MTPABP were the same except that the Chol-yne unit was not added. Figure 6 The results of coating plates with different materials on E. coli show that at a concentration of 1 μg / mL and the same culture time, PEI and PEI-MTPABP have no obvious killing effect on E. coli, while PEI-MTPABP-Chol shows a good killing effect on E. coli.

[0084] Figure 7 ,and Figure 8 These are the results of coating plates with the nanoparticles obtained in Example 1 on Staphylococcus aureus and Candida albicans, with the nanoparticle concentrations being 1 μg / mL and 4 μg / mL, respectively, proving that the fluorescent probe can produce a strong photodynamic killing effect on a variety of bacteria at relatively low concentrations.

[0085] Example 7

[0086] Imaging of biofilm using PEI-MTPABP-Chol nanoparticles

[0087] Fig. 9 This is the CLSM image of PEI-MTPABP-Chol nanoparticles imaging the bioplasma membrane of fungi (C.albican) and cells (Hela). The concentration of the nanoparticles used was 10μg / mL. After incubation with Candida albicans and HeLa cells for a period of time, it can be clearly seen under the laser confocal microscope that the fluorescence is basically concentrated in the cell membrane part, indicating that the prepared fluorescent probe has good specific staining ability for the bioplasma membrane system.

[0088] Fig.10The CLSM diagrams of the internalization degree of the material by the cells at different times under the condition of long-term incubation of PEI-MTPABP-Chol nanoparticles and Hela cells. The current commercial dyes have a short imaging time for cell membranes (30-90min), while the fluorescent probe obtained based on Example 1 not only has good imaging ability for cell membranes, but also relies on the hydrophobic anchoring effect of lipid molecules, coupled with the large steric hindrance under the aggregation state of AIE molecules, the fluorescent probe has a long residence time on the cell membrane, and the internalization degree is very small even under the condition of co-culture for 4h, showing its potential as a cell membrane dye.

[0089] The above embodiments are preferred implementation methods of the present invention, but the implementation methods of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. A fluorescent probe of an AIE molecule-modified cationic polymer, characterized in that: The structure is as follows: Wherein, A is a polyamino cationic polymer, B is an AIE photosensitizer, and C is a hydrophobic component; A and B, A and C are connected by chemical bonds respectively; the molar amount of B is 1%-3% of the molar amount of amino groups in A; the molar amount of C is 1%-3% of the molar amount of amino groups in A; The polyamino cationic polymer is at least one of polyethyleneimine, polypropyleneimine, polylysine, polyamide-amine dendrimers, polyaminoesters, and chitosan; The AIE photosensitizer is MTPABP-pyo, and the structural formula is as follows: The hydrophobic component is Chol-yne, and the structural formula is as follows:

2. The fluorescent probe of the AIE molecule modified cationic polymer according to claim 1, characterized in that: The polyamino ester is poly(β-amino ester).

3. The method for preparing a fluorescent probe of an AIE molecule modified cationic polymer according to any one of claims 1 to 2, characterized in that: The steps include: The AIE photosensitizer B and the hydrophobic component C dissolved in the organic solvent 1 are added to the solution of the polyamino cationic polymer A dissolved in the protic solvent 2, and reacted for 3-5 hours to obtain a fluorescent probe of the AIE molecule modified cationic polymer.

4. The preparation method according to claim 3, characterized in that: The organic solvent 1 is tetrahydrofuran; the protic solvent 2 is methanol; and the step of adding the AIE photosensitizer B and the hydrophobic component C dissolved in the organic solvent 1 to the solution of the polyamino cationic polymer A dissolved in the protic solvent 2 is carried out under ice bath conditions.

5. A nanoparticle prepared by a fluorescent probe of a cationic polymer modified by an AIE molecule according to any one of claims 1 to 2.

6. The method for preparing nanoparticles according to claim 5, characterized in that: The following steps are involved: The fluorescent probe of the AIE molecule-modified cationic polymer is dissolved in the organic solvent 3, and then added into ultrapure water and stirred until the organic solvent 3 is completely volatilized to obtain nanoparticles.

7. The preparation method according to claim 6, characterized in that: The organic solvent 3 is THF; the AIE molecule-modified cationic polymer fluorescent probe, the organic solvent 3 and ultrapure water have a mass volume ratio of 5-20 mg: 0.5-1mL:5-20mL.

8. Use of the fluorescent probe of the AIE molecule modified cationic polymer according to any one of claims 1 to 2 or the nanoparticles according to claim 5 in the preparation of cell imaging reagents, cell staining reagents, and antibacterial reagents.

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