Azo compound, amphiphilic azo fluorescent compound, preparation methods and applications of azo compound and amphiphilic azo fluorescent compound, nano antibacterial agent and preparation method of nano antibacterial agent

Abstract

The invention relates to the technical field of azo switches, and discloses an azo compound, an amphiphilic azo fluorescent compound, preparation methods and applications of the azo compound and the amphiphilic azo fluorescent compound, a nano antibacterial agent and a preparation method of the nano antibacterial agent. The amphiphilic azo fluorescent compound has a structure as shown in a formula (I). A nano preparation (namely the nano antibacterial agent) taking the amphiphilic azo fluorescent compound as a carrier can realize light-controlled release of drugs, and the controlled release process can be visually detected through an imaging technology.

Description

Technical Field

[0001] This invention relates to the field of azo switch technology, specifically to azo compounds and amphiphilic azo fluorescent compounds and their preparation methods and applications, as well as nano-antibacterial agents and their preparation methods. Background Technology

[0002] Azobenzene, capable of undergoing reversible cis-trans isomerization, is one of the simplest and most stable photoswitches. Its phototriggered switching properties have been used to regulate chemical reactions, control drug activity, and modulate metabolic processes in organisms.

[0003] In recent years, non-invasive fluorescence imaging technology has proven beneficial for monitoring various dynamic processes. An azo fluorescent switch prepared by combining this technology with an azo photoswitcher can induce structural transformations under illumination and perform fluorescence imaging of the resulting in vitro and in vivo changes.

[0004] In previous research, our team has demonstrated that a nano-controlled release system constructed using an azo switch as a photoresponsive component can release drugs in an orderly and controllable manner, and the process can be visualized and detected using fluorescence imaging technology.

[0005] Some studies have shown that controlled-release nanocarriers modified with azo-based photoresponsive molecules have demonstrated the ability to effectively improve drug utilization and reduce environmental pollution in fields such as drug controlled release and nanopesticides.

[0006] In summary, to further improve the controlled release capability of azo fluorescent nanosystems and track the controlled release process, it is necessary to develop amphiphilic azo fluorescent molecular switches and synthesize and apply nanoparticles using them as nanocarriers. Summary of the Invention

[0007] The purpose of this invention is to provide a new compound that can be used for fluorescent light switches and its applications.

[0008] To achieve the above objectives, a first aspect of the present invention provides an azo compound having the structure shown in formula (A):

[0009]

[0010] In equation (A), R represents H and C. 1-6 Any one of the alkyl groups.

[0011] A second aspect of the present invention provides a method for preparing the azo compound described in the first aspect, the method comprising: reacting a compound with the structure shown in formula (A-1) with a compound with the structure shown in formula (A-2) to obtain the azo compound shown in formula (A);

[0012] CH3OC(O)CH2-X (A-2)

[0013] In formula (A-2), X is any one of the halogens.

[0014] A third aspect of the invention provides the use of the azo compound described in the first aspect in the preparation of amphiphilic azo fluorescent compounds.

[0015] A fourth aspect of the present invention provides an amphiphilic azo fluorescent compound having the structure shown in formula (I):

[0016]

[0017] In equation (I), n is an integer between 6 and 20.

[0018] The fifth aspect of the present invention provides the use of the amphiphilic azo fluorescent compound described in the fourth aspect as a fluorescent photoswitching carrier.

[0019] The sixth aspect of the present invention provides the application of the amphiphilic azo fluorescent compound described in the fourth aspect in a nano-controlled release system.

[0020] A seventh aspect of the present invention provides a method for preparing the amphiphilic azo fluorescent compound described in the fourth aspect, the method comprising: esterifying a compound with the structure shown in formula (B) with nonaethylene glycol to obtain the amphiphilic azo fluorescent compound shown in formula (I);

[0021]

[0022] The eighth aspect of the present invention provides a nano-antibacterial agent comprising a nanocarrier and a small molecule drug with a molecular weight not greater than 1000 loaded in the nanocarrier; wherein the nanocarrier is the amphiphilic azo fluorescent compound described in the fourth aspect.

[0023] The ninth aspect of the present invention provides a method for preparing the nano-antibacterial agent described in the eighth aspect, the method comprising: mixing a solution I containing an amphiphilic azo photoswitcher and a solution II containing a small molecule drug using a matrix encapsulation method to obtain the nano-antibacterial agent.

[0024] The amphiphilic azo fluorescent compound provided by this invention can be used as a fluorescent light switch in nano-controlled release systems.

[0025] The amphiphilic azo fluorescent compound provided by the present invention has phenyl heteroaromatic azo structures on both sides and uses polyethylene glycol as a bridging skeleton.

[0026] The nano-antibacterial agent provided by this invention is based on an amphiphilic azo fluorescent compound molecular switch and loads small molecule drugs through its self-assembly.

[0027] The nano-antibacterial agent provided by this invention involves nanoparticles, and the provided amphiphilic azo photoswitch can switch back and forth between trans and cis configurations under irradiation with visible light of different wavelengths.

[0028] The nano-formulations (i.e., the nano-antibacterial agents of the present invention) using the amphiphilic azo fluorescent compounds of the present invention as carriers can not only achieve photocontrolled drug release, but the controlled release process can also be visualized and detected by imaging technology.

[0029] The preparation method of the amphiphilic azo fluorescent compound provided by this invention is simple.

[0030] Furthermore, the amphiphilic azo fluorescent light switch provided by this invention is expected to provide an effective strategy for the design and synthesis of other light-controlled fluorescent carriers.

[0031] The nano-antibacterial agent using the amphiphilic azo fluorescent compound of the present invention as a carrier can realize the photocontrolled release of the bactericide and the monitoring of the controlled release process. Attached Figure Description

[0032] Figure 1 The amphiphilic azo compound 1 (Bis-AzoPEG) prepared in Preparation Example 1 of this invention is used as an azo switch at 440 nm (20 W cm⁻¹). -2 ) or 535nm (15W cm -2 )Graph showing the change of absorption spectrum under visible light irradiation over time; Figure 1 Figure A shows the change of the absorption spectrum of the amphiphilic azo switch over time under 440nm light illumination. Figure 1 B represents the change in the absorption spectrum of the amphiphilic azo switch after irradiation with 440nm light and then irradiation with 535nm visible light.

[0033] Figure 2 The amphiphilic azo compound 1 (Bis-AzoPEG) prepared in Preparation Example 1 of this invention is used as an azo switch at 440 nm (20 W cm⁻¹). -2 ) or 535nm (15W cm -2 Emission spectrum variation under visible light illumination; Figure 2 A represents the emission spectrum change of the azo switch under 440nm light illumination; Figure 2 B represents the emission spectrum change after irradiation with 535nm visible light following the isomerization of azo switch after irradiation with 440nm light;

[0034] Figure 3 The nano-antibacterial agent (Bis-AzoPEG-FP NPs) prepared in Example 1 of this invention is at 440 nm (20W cm⁻¹). -2) or 535nm (15W cm -2 ) Absorption spectrum changes under visible light irradiation; Figure 3 A represents the change in the absorption spectrum of the nano-antibacterial agent under 440nm light illumination; Figure 3 B represents the change in absorption spectrum after 10 minutes of 440nm light irradiation followed by 535nm visible light irradiation.

[0035] Figure 4 The nano-antibacterial agent (Bis-AzoPEG-FP NPs) prepared in Example 1 of this invention exhibits high performance under 440 nm visible light (20 W / cm²). -2 Particle size distribution diagram under irradiation;

[0036] Figure 5 The nano-antibacterial agent (Bis-AzoPEG-FP NPs) prepared in Example 1 of this invention was subjected to 440nm light irradiation (20W cm⁻¹). -2 Microscopic images before and after, scale bar = 20 nm;

[0037] Figure 6 This is a schematic diagram of the synthetic route for preparing nano-antibacterial agents (Bis-AzoPEG-FP NPs) in Example 1 of the present invention. Detailed Implementation

[0038] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0039] The structural formula of the nonaglycol described in this invention is:

[0040]

[0041] The structural formula of the phenyl ether azole amide described in this invention is:

[0042]

[0043] Unless otherwise specified, the amphiphilic azo fluorescent compounds of this invention include their cis and / or trans structures. If it is a mixture of cis and trans structures, there are no special requirements for the mixing ratio; the molar ratio of the cis and trans structures can be 1%:99%, 2%:98%, 3%:97%, 4%:96%, 5%:95%, 6%:94%, 7%:93%, 8%:92%, 9%:91%, 10%:90%, 11%:89%, 12%:88%, 13%:87%, 14%:86%, 15%:85%, 16%:84%, 17%:83%, 18%:82%, 19%:81%, 20%:80%, 25%:75%, 30%:70%, 3... 5%:65%, 40%:60%, 45%:55%, 50%:50%, 55%:45%, 60%:40%, 65%:35%, 70%:30%, 75%:25%, 80%:20%, 81%:19%, 82%:18%, 83%:17%, 84%:16%, 85%:15%, 86%:14%, 87%:13%, 88%:12%, 89%:11%, 90%:10%, 91%:9%, 92%:8%, 93%:7%, 94%:6%, 95%:5%, 96%:4%, 97%:3%, 98%:2%, or 99%:1%.

[0044] As previously stated, a first aspect of the present invention provides an azo compound having the structure shown in formula (A):

[0045]

[0046] In equation (A), R represents H and C. 1-6 Any one of the alkyl groups.

[0047] Preferably, R is any one of H, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, and tert-butyl.

[0048] Particularly preferably, R is H or methyl. When R is H, the azo compound is also a compound with the structure shown in formula (B).

[0049] As previously stated, a second aspect of the present invention provides a method for preparing the azo compound described in the first aspect, the method comprising: reacting a compound with the structure shown in formula (A-1) with a compound with the structure shown in formula (A-2) to obtain the azo compound shown in formula (A);

[0050] CH3OC(O)CH2-X (A-2)

[0051] In formula (A-2), X is any one of the halogens.

[0052] Preferably, X in formula (A-2) is Br.

[0053] The present invention does not have any particular requirements on the source of the compounds with the structure shown in formula (A-1) and the compounds with the structure shown in formula (A-2). They can be prepared by methods known in the art or obtained commercially.

[0054] According to a particularly preferred embodiment, the compound with the structure shown in formula (A-1) is prepared by a method comprising the following steps:

[0055] (1) Under acidic conditions, N,N-dimethyl-p-phenylenediamine and sodium nitrite are first contacted and mixed to obtain a diazonium salt; then, under pH ≤ 7.5 conditions, in the presence of a solvent, the diazonium salt is reacted with a compound with the structure shown in formula (A-3) to obtain an azo intermediate with the structure shown in formula (A-4);

[0056]

[0057] (2) The azo intermediate with the structure shown in formula (A-4) was mixed with hydrazine hydrate in an ethanol solution in a second contact to obtain the compound with the structure shown in formula (A-1).

[0058] Preferably, in step (1), the acidic conditions are formed by at least one strong acid selected from hydrochloric acid, sulfuric acid and nitric acid.

[0059] Preferably, in step (1), the molar ratio of N,N-dimethyl-p-phenylenediamine to sodium nitrite is 1:1.1-1.5.

[0060] Preferably, in step (1), the conditions for the first contact mixing include: a temperature of -10°C to 5°C and a time of 10 min to 60 min. More preferably, in step (1), the temperature of the first contact mixing is 0-5°C.

[0061] Preferably, in step (1), the obtained diazonium salt is first subjected to pH adjustment treatment so that the pH value of the diazonium salt is ≤7.5 before the synthesis reaction is carried out, more preferably the pH value of the diazonium salt is ≤7.0, and particularly preferably the pH value of the diazonium salt is adjusted to 6.5-7.0.

[0062] Preferably, the pH adjustment is performed by applying a buffer solution. More preferably, the buffer solution contains NaOAc.

[0063] Preferably, in step (1), the conditions for the synthesis reaction include: a temperature of 75-85°C and a time of 3-12 hours.

[0064] The present invention does not have any special requirements for the solvent used in step (1), and various solvents known and commonly used in the art can be used. Further details of the present invention will not be elaborated here, and those skilled in the art should not construe this as a limitation of the present invention.

[0065] Preferably, in step (2), the conditions for the second contact mixing include reacting under reflux conditions for 6-24 hours.

[0066] As previously stated, a third aspect of the present invention provides the use of the azo compounds described in the first aspect in the preparation of amphiphilic azo fluorescent compounds.

[0067] As previously stated, a fourth aspect of the present invention provides an amphiphilic azo fluorescent compound having the structure shown in formula (I):

[0068]

[0069] In equation (I), n is an integer between 6 and 20.

[0070] More preferably, n is 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20. Particularly preferably, n is 8, 10, 12, 14 or 16.

[0071] As previously stated, the fifth aspect of the present invention provides the use of the amphiphilic azo fluorescent compound described in the fourth aspect as a fluorescent photoswitching carrier.

[0072] The amphiphilic azo fluorescent compound described in this invention can be used as a light switch.

[0073] As previously stated, the sixth aspect of the present invention provides the application of the amphiphilic azo fluorescent compound described in the fourth aspect in a nano-controlled release system.

[0074] The amphiphilic azo fluorescent compound described in this invention can be used as a nanocarrier in nano-controlled release systems.

[0075] As previously stated, the seventh aspect of the present invention provides a method for preparing the amphiphilic azo fluorescent compound described in the fourth aspect, the method comprising: esterifying a compound with the structure shown in formula (B) with nonaethylene glycol to obtain the amphiphilic azo fluorescent compound shown in formula (I).

[0076]

[0077] Preferably, the esterification reaction is carried out in the presence of a catalyst.

[0078] Preferably, the catalyst is selected from at least one of HBTU and DMAP.

[0079] Preferably, the esterification reaction is carried out in the presence of DIPEA.

[0080] As previously stated, the eighth aspect of the present invention provides a nano-antibacterial agent comprising a nanocarrier and a small molecule drug with a molecular weight not greater than 1000 encapsulated in the nanocarrier; wherein the nanocarrier is the amphiphilic azo fluorescent compound described in the fourth aspect.

[0081] Preferably, the small molecule drug is selected from at least one of a fungicide and a bactericide.

[0082] Particularly preferably, the small molecule drug is selected from at least one of difenoconazole, flufenoxuron, and avermectin.

[0083] Preferably, the loading rate of the small molecule drug is 40% or more. More preferably, the loading rate of the small molecule drug is 60% or more.

[0084] The encapsulation rate (EE%) = (total added mass of drug - mass of unencapsulated drug) / total added mass of drug.

[0085] In the nano-antibacterial agent provided by the present invention, drug molecules can be encapsulated inside the azo nanocarrier. During the preparation process, since the azo compound is amphiphilic, it can form a spherical structure, thereby loading the drug molecules inside, while molecules that are not loaded can be removed by ultrafiltration centrifugation.

[0086] As previously stated, the ninth aspect of the present invention provides a method for preparing the nano-antibacterial agent described in the eighth aspect, the method comprising: mixing a solution I containing an amphiphilic azo photoswitcher and a solution II containing a small molecule drug using a matrix encapsulation method to obtain the nano-antibacterial agent.

[0087] Preferably, the mass ratio of the small molecule drug to the amphiphilic azo photoswitch is 1:5-15.

[0088] Preferably, the solvent in solution I and solution II is tetrahydrofuran.

[0089] Preferably, the mixing process is performed under ultrasonic conditions.

[0090] Preferably, the ultrasonic conditions include: an ultrasonic frequency of 35-45 kHz and an ultrasonic time of 10-30 min.

[0091] The present invention does not have any particular requirements for the preparation methods of solution I and solution II. For example, the solute and solvent can be mixed under ultrasonic conditions. Furthermore, there are no particular requirements for the ultrasonic mixing time in this step, which can be, for example, 1 min to 20 min.

[0092] According to a particularly preferred embodiment, the method for preparing the nano-antibacterial agent described in the eighth aspect comprises: using a matrix encapsulation method, performing a first mixing treatment on a tetrahydrofuran solution I containing an amphiphilic azo photoswitcher and a tetrahydrofuran solution II containing a small molecule drug to obtain a first solution; and then performing a second mixing treatment on the first solution and an aqueous solution to obtain the nano-antibacterial agent.

[0093] Preferably, in solution I, the concentration of the amphiphilic azo photoswitch is 0.8-2 mg / mL.

[0094] Preferably, in solution II, the concentration of the small molecule drug is 0.1-0.2 mg / mL.

[0095] The present invention does not have any special requirements for the specific operation of the matrix encapsulation method. Those skilled in the art can use the methods provided in the literature known in the art. The present invention will not elaborate further here, and those skilled in the art should not understand it as a limitation of the present invention.

[0096] The average particle size of the nano antibacterial agent of the present invention is preferably 600 nm to 1000 nm, more preferably 650 nm to 900 nm.

[0097] In all the preparation methods of this invention, post-processing known in the art may be included. This invention does not impose special requirements on the specific operations and conditions of such post-processing; conventional operations and conditions used in the art can be employed, such as filtering and collecting the obtained precipitate, performing chromatographic purification, drying, etc. This invention is not described in detail herein, and those skilled in the art should not construe it as a limitation of the invention.

[0098] According to a particularly preferred embodiment of the present invention, a method for preparing the amphiphilic azo fluorescent compound described in the fourth aspect comprises:

[0099] (1) Under acidic conditions, N,N-dimethyl-p-phenylenediamine and sodium nitrite are first contacted and mixed to obtain a diazonium salt; then, under pH ≤ 7.5 conditions, in the presence of a solvent, the diazonium salt is reacted with a compound with the structure shown in formula (A-3) to obtain an azo intermediate with the structure shown in formula (A-4);

[0100] (2) The azo intermediate with the structure shown in formula (A-4) was mixed with hydrazine hydrate in an ethanol solution in a second contact to obtain the compound with the structure shown in formula (A-1);

[0101] (3) The compound with the structure shown in formula (A-1), potassium carbonate and the compound with the structure shown in formula (A-2) are reacted in an ethanol solution to obtain the azo compound shown in formula (A1);

[0102] (4) The azo compound shown in formula (A1) and lithium hydroxide are contacted and mixed in a tetrahydrofuran / water solution to obtain the azo compound shown in formula (B);

[0103] (5) The compound with the structure shown in formula (B) was subjected to an esterification reaction with nonaethylene glycol to obtain the amphiphilic azo fluorescent compound shown in formula (I);

[0104]

[0105] CH3OC(O)CH2-X (A-2)

[0106] The present invention will be described in detail below through examples. In the following examples, unless otherwise specified, the raw materials used are common commercially available products.

[0107] The room temperature or normal temperature mentioned in this invention refers to 25±2℃.

[0108] Preparation example: An amphiphilic azo fluorescent compound, named Bis-AzoPEG, was synthesized via the following synthetic route:

[0109]

[0110] The specific steps include:

[0111] (1) N,N-dimethyl-p-phenylenediamine (22 mmol) was dispersed in 35 mL of acetic acid, and after stirring, hydrochloric acid (12 M, 5.8 mL) was added. Subsequently, an aqueous solution of sodium nitrite (26 mmol) was slowly added to the above solution. After stirring in an ice-water bath for 30 min, the pH of the resulting diazonium salt solution was adjusted by adding an aqueous solution of sodium acetate. When the pH reached 6.5, an ethanolic solution of acetylacetone (28 mmol) was added. The mixture was stirred at room temperature for 24 hours, and the crude product was collected by vacuum distillation. The crude product was purified by column chromatography to give a red azo intermediate in 32% yield.

[0112] (2) The azo intermediate (12 mmol) from step (1) was dissolved in an ethanol solution, and hydrazine hydrate (30 mmol) dissolved in ethanol was added. The mixture was refluxed for 12 hours, and the crude product was collected by vacuum distillation. The crude product was purified by column chromatography to obtain a yellow azo intermediate with a yield of 67%.

[0113] (3) Dissolve the azo intermediate (3 mmol) and potassium carbonate (9 mmol) from step (2) in acetonitrile solution, then add methyl bromoacetate (3.9 mmol) to the mixture, reflux for 12 hours, and collect the crude product by vacuum distillation. The crude product is purified by column chromatography to obtain a yellow azo intermediate in 80% yield.

[0114] (4) The azo intermediate (10 mmol) from step (3) was dissolved in tetrahydrofuran solution, followed by the addition of lithium hydroxide (15 mmol) dissolved in water, and stirred at room temperature for 48 hours. After acid extraction, the azo intermediate was obtained in 89% yield.

[0115] (5) The azo intermediate from step (4), nonaethylene glycol, HBTU, and DMAP were dissolved in a mixed solution of N,N-dimethylformamide and chloroform. N,N-diisopropylethylamine was added, and the mixture was stirred at room temperature for 48 hours. The crude product was collected by vacuum distillation. The crude product was purified by column chromatography to obtain an orange amphiphilic azo compound with a yield of 23%.

[0116] The characterization results are as follows:

[0117] 1 H NMR (600MHz, CDCl3): δ=7.75(d,2H),7.73(d,2H),6.75(d,2H),6.73(d,2H),4.86(s,4H),4.33(s,4H),3.70(s,4H ), 3.63 (s, 19H), 3.62 (s, 8H), 3.05 (s, 12H), 2.53 (s, 6H), 2.49 (s, 6H). LC-MS: m / z=981.5401[M]+; calculated value=981.5331.

[0118] The absorption spectrum and fluorescence emission spectrum (excitation wavelength 370 nm) of Bis-AzoPEG were tested and are shown below. Figure 1 , Figure 2 As shown.

[0119] Figure 1 Figure A shows the change in the absorption spectrum of the amphiphilic azo switch as the irradiation time increases under 440nm illumination. Figure 1The 'B' represents the image showing the change in the absorption spectrum of azo molecules over time after 10 seconds of light exposure at 440nm, when they reach a photosteady state, followed by further exposure to 535nm light. (Example:) Figure 1 As shown, the azo switch spectrum changed significantly with increasing 440 nm illumination time. After reaching photosteady state, the molecule exhibited two distinct absorption peaks at 376 nm and 453 nm, indicating that trans-Bis-AzoPEG underwent photoisomerization to generate cis-Bis-AzoPEG. To verify the reversibility of this cis-trans isomerism, cis-Bis-AzoPEG was irradiated with 535 nm green light. The results showed that with increasing irradiation time, the molecule gradually transformed into trans-Bis-AzoPEG, and after 120 seconds of irradiation, its absorption almost completely recovered to the initial state. These results indicate that Bis-AzoPEG possesses excellent photoisomerization properties and is a typical visible light-induced molecular switch.

[0120] Subsequently, the fluorescence spectrum of Bis-AzoPEG was further tested, and the results are as follows: Figure 2 As shown, Figure 2 Figure A shows the emission spectrum change of the amphiphilic azo switch under 440nm illumination; Figure 2 B represents the emission spectrum change of the amphiphilic azo switch isomer after irradiation with 440nm light and then irradiated with 535nm visible light. (See diagram for example.) Figure 2 As shown, Bis-AzoPEG exhibits a distinct emission peak in the 420-461 nm region in DMSO. Irradiation with 440 nm light significantly alters its fluorescence spectrum. With prolonged irradiation, the trans-azo molecule isomerizes to form the cis-azo molecule. When irradiation is switched to 535 nm light, the fluorescence spectrum returns to its initial state. These experimental results demonstrate that Bis-AzoPEG possesses excellent photo-switching performance and photocontrolled fluorescence characteristics.

[0121] Example: Synthesis of Nano-Antibacterial Agents

[0122] The synthesis route in this embodiment is as follows: Figure 6 As shown, the process includes: self-assembling an amphiphilic azo photoswitch with an antibacterial agent (drug molecule) to obtain a nano-formulation (Bis-AzoPEG-FP NPs) loaded with drug molecules. The specific synthesis steps are as follows:

[0123] First, the amphiphilic azo fluorescent photoswitch Bis-AzoPEG-FP and difenoconazole amide (analytical grade, drug molecule) were dissolved in tetrahydrofuran and sonicated separately. Then, the two were mixed and sonicated, and deionized water was slowly added dropwise to the mixture. After removing the tetrahydrofuran with a nitrogen stream, the mixture was centrifuged and brought to a final volume to obtain the nano-formulation Bis-AzoPEG-FP NPs.

[0124] Performance tests were conducted on the nano-antibacterial agent Bis-AzoPEG-FP NPs. Specifically, the absorption spectra of the nano-antibacterial agent Bis-AzoPEG-FP NPs in this embodiment after irradiation with visible light at 440 nm and 535 nm are shown below. Figure 3 As shown, Figure 3 A represents the change in the absorption spectrum of the nano-antibacterial agent under 440nm light illumination; Figure 3 B represents the change in absorption spectrum after 10 minutes of 440nm light irradiation, followed by 535nm visible light irradiation. Furthermore, Figure 3 As shown in Figure A, the untreated nano-antibacterial agent exhibits broad absorption in the 360-480 nm region. After 10 minutes of irradiation with 440 nm light, the absorption spectrum of Bis-AzoPEG-FP NPs changed significantly, with maximum absorption at 390 nm, indicating that the amphiphilic azo compound supporting the nano-antibacterial agent underwent isomerization. To verify the reversibility of this process, the nano-solution, which had undergone significant changes, was further irradiated with 535 nm green light. The results showed that the spectrum of the nano-antibacterial agent essentially returned to its original state after 60 minutes of 535 nm light irradiation. These results demonstrate that the nano-antibacterial agent Bis-AzoPEG-FP NPs changes under visible light irradiation due to the reversible isomerization of the amphiphilic azo molecules.

[0125] The particle size distribution of the nano-antibacterial agent (Bis-AzoPEG-FP NPs) in this embodiment after irradiation with 440nm visible light is shown in the figure below. Figure 4 As shown. From Figure 4 As can be seen, the size of the nanoparticles decreased significantly after irradiation with 440 nm light; DLS results showed that the average particle size decreased from 823 nm to 203 nm. This is mainly attributed to the isomerization of the azo switch in the nano-formulation under 440 nm light irradiation, which caused the nanoparticles to shrink.

[0126] The microscopic imaging results of the nano-antibacterial agent (Bis-AzoPEG-FP NPs) in this embodiment after light irradiation are as follows: Figure 5 As shown. From Figure 5 As can be seen, the untreated nano-bacterial agent (Bis-AzoPEG-FP NPs) exhibits a distinct spherical structure. After irradiation with 440 nm light, a decrease in the number and size of the nanoparticles can be observed. This result indicates that the nano-formulation undergoes significant structural changes under light irradiation.

[0127] The above results demonstrate that the amphiphilic azo fluorescent compound provided by this invention exhibits visible light isomerism and can serve as a novel amphiphilic azo light switch. Furthermore, the nano-formulations formed using the amphiphilic azo fluorescent compound of this invention as a nanocarrier show significant changes in morphology and size under visible light irradiation, and this process can be visualized using microscopic imaging techniques.

[0128] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. An azo compound, characterized in that, The compound has the structure shown in formula (A): In equation (A), R represents H and C. 1-6 Any one of the alkyl groups.

2. A method for preparing the azo compound of claim 1, characterized in that, The method includes: reacting a compound with the structure shown in formula (A-1) with a compound with the structure shown in formula (A-2) to obtain the azo compound shown in formula (A); CH3OC(O)CH2-X (A-2) In formula (A-2), X is any one of the halogens.

3. The use of the azo compound as described in claim 1 in the preparation of amphiphilic azo fluorescent compounds.

4. An amphiphilic azo fluorescent compound, characterized in that, The compound has the structure shown in formula (I): In equation (I), n is an integer between 6 and 20.

5. The application of the amphiphilic azo fluorescent compound of claim 4 as a fluorescent photoswitching carrier.

6. The application of the amphiphilic azo fluorescent compound of claim 4 in a nano-controlled release system.

7. A method for preparing the amphiphilic azo fluorescent compound of claim 4, characterized in that, The method includes: esterifying a compound with the structure shown in formula (B) with nonaethylene glycol to obtain an amphiphilic azo fluorescent compound shown in formula (I); Preferably, the esterification reaction is carried out in the presence of a catalyst.

8. A nano-antibacterial agent, characterized in that, The nano-antibacterial agent contains a nano-carrier and a small molecule drug with a molecular weight of no more than 1000 encapsulated in the nano-carrier; the nano-carrier is the amphiphilic azo fluorescent compound as described in claim 4; Preferably, the small molecule drug is selected from at least one of a fungicide and a bactericide; Preferably, the small molecule drug has a loading rate of 60% or higher.

9. A method for preparing the nano-antibacterial agent according to claim 8, characterized in that, The method includes: using a matrix encapsulation method, mixing solution I containing an amphiphilic azo photoswitch and solution II containing a small molecule drug to obtain the nano-antibacterial agent; Preferably, the mixing process is performed under ultrasonic conditions; Preferably, the ultrasonic conditions include: an ultrasonic frequency of 35-45 kHz and an ultrasonic time of 10-30 min.

10. The method according to claim 9, characterized in that, The solvent in both solution I and solution II is tetrahydrofuran.

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