Near-infrared two-region imaging material as well as preparation method and application thereof

Abstract

The invention discloses a near-infrared two-region imaging material and a preparation method and application thereof, and belongs to the technical field of photoelectric functional materials. The near-infrared two-region imaging material is an aza-fluorine boron pyrrole derivative NJ1040; the preparation method comprises the following steps: dissolving 2-acetylthiophene in ethanol to obtain a mixed solution, adding a potassium hydroxide aqueous solution, stirring, adding 4-diethylaminobenzaldehyde, stirring, and extracting; drying the extracted organic phase, and performing rotary evaporation concentration and purification to obtain an intermediate I; mixing the intermediate I, diethylamine and nitromethane, reacting, extracting, drying the extracted organic phase, and performing rotary evaporation concentration and purification to obtain an intermediate II; mixing the intermediate II, ammonium acetate and ethanol for reaction, adding triethylamine and a boron trifluoride diethyl etherate complex for continuous reaction after rotary evaporation concentration, and extracting; and drying the extracted organic phase, carrying out rotary evaporation concentration, and purifying to obtain the product. NJ1040 nanoparticles are prepared by a nano coating technology, so that the problem of poor solubility of a contrast agent is solved.

Description

Technical Field

[0001] This invention belongs to the field of optoelectronic functional materials technology, specifically relating to a near-infrared II imaging material, its preparation method, and its application. Background Technology

[0002] Near-infrared fluorescence imaging has become an important tool in biomedical research due to its non-invasiveness, real-time dynamic monitoring, and high sensitivity. However, traditional near-infrared I (NIR-I, 700–950 nm) imaging is limited by the strong absorption and scattering of short-wavelength light by biological tissues, resulting in insufficient imaging depth (<3 mm) and low spatial resolution, making it difficult to meet the high-precision imaging requirements of deep tissues (such as tumors and cerebral blood vessels). Compared to the visible light region and near-infrared I, near-infrared II (NIR-II) fluorophores have deeper tissue penetration depth, lower tissue autofluorescence interference, and higher spatial resolution, which makes them show great application potential in cutting-edge fields such as bioimaging, disease diagnosis, and phototherapy.

[0003] However, existing NIR-II fluorophores still have limitations. For example, the clinically commonly used indocyanine green (ICG) has an extremely low quantum yield in NIR-II, resulting in weak signal intensity. Inorganic quantum dots or rare earth nanomaterials have potential toxicity, and small organic molecules often cause fluorescence quenching during the nano-sizing process, affecting imaging performance. Therefore, the development of NIR-II fluorophores faces many severe technical bottlenecks.

[0004] Furthermore, in the NIR-II region, the required excitation and emission wavelengths are relatively long, resulting in a relatively small band gap. This leads to nonradiative transitions dominating the excited-state deactivation pathway. During nonradiative transitions, the excited-state energy is dissipated as heat rather than emitted as photons, resulting in a lower fluorescence quantum yield (Φ). f (Generally below 1%) Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a near-infrared II imaging material, its preparation method, and its application, thereby solving the problems in the prior art.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A near-infrared II imaging material, namely the azirmono-boron pyrrole derivative NJ1040, has the following molecular structure:

[0008]

[0009] The above-mentioned method for preparing a near-infrared II imaging material includes the following steps:

[0010] 2-Acetylthiophene was dissolved in ethanol to obtain a mixed solution. Potassium hydroxide aqueous solution was added and stirred. Then 4-diethylaminobenzaldehyde was added, stirred, and extracted. The extracted organic phase was dried, concentrated by rotary evaporation, and purified to obtain intermediate I.

[0011] Intermediate I, diethylamine and nitromethane were mixed, reacted and extracted. The extracted organic phase was dried, concentrated and purified by rotary evaporation to obtain intermediate II.

[0012] Intermediate II, ammonium acetate, and ethanol were mixed and reacted, concentrated by rotary evaporation, and then triethylamine and boron trifluoride diethyl ether complex were added to continue the reaction and extraction. The extracted organic phase was dried, concentrated by rotary evaporation, and purified to obtain the near-infrared II imaging material.

[0013] Furthermore, the molar ratio of 2-acetylthiophene to 4-diethylaminobenzaldehyde is 1:1.

[0014] Furthermore, the molar ratio of intermediate I, diethylamine, and nitromethane is 1:2:2.

[0015] Furthermore, the molar ratio of intermediate II, ammonium acetate, and boron trifluoride diethyl ether complex is 1:15:5.

[0016] The above-mentioned near-infrared II imaging materials are used in bioimaging.

[0017] A method for preparing near-infrared II imaging material nanoparticles includes the following steps:

[0018] The near-infrared II imaging material of claim 1 is dissolved in tetrahydrofuran to obtain solution A; the coating agent is dissolved in deionized water to obtain solution B;

[0019] Solution B was subjected to sonication, and then solution A was injected into solution B. The sonication was continued intermittently to obtain a coating solution.

[0020] After stirring the coating solution, ultrafiltration centrifugation and concentration were performed; then the concentrated product was washed to obtain near-infrared II imaging material nanoparticles.

[0021] Furthermore, the coating agent is Pluronic F-127, and the mass ratio of Pluronic F-127 to the near-infrared II imaging material is 10:1.

[0022] A near-infrared II imaging material nanoparticle was prepared using the aforementioned method for preparing near-infrared II imaging material nanoparticles.

[0023] The aforementioned near-infrared II imaging material nanoparticles are used as contrast agents in bioimaging, and the application is for non-diagnostic purposes.

[0024] The beneficial effects of this invention are:

[0025] 1. By designing the D-π-A type Aza-BODIPY derivative molecule NJ1040, the non-radiative transition process is suppressed while reducing the singlet-triplet energy level difference, thus achieving efficient fluorescence emission and effectively improving luminescence efficiency.

[0026] 2. NJ1040 nanoparticles were prepared using nano-coating technology, which solved the problem of poor contrast agent solubility. Experimental results showed that the NIR-II emission peak of NJ1040 nanoparticles was located in the range of 1000-1700 nm, and the fluorescence quantum efficiency reached 5.68%, which was 5 times higher than that of commercial ICG. As a contrast agent, NJ1040 nanoparticles obtained clear and high signal-to-noise ratio biofluorescence imaging results in angiography of live mice.

[0027] 3. In this invention, the molar ratio of 2-acetylthiophene to 4-diethylaminobenzaldehyde is 1:1. From a stoichiometric perspective, a 1:1 molar ratio ensures sufficient contact and reaction between the two reactants, allowing the reaction to proceed according to the expected chemical equation, improving the utilization rate of raw materials, and reducing the residue of unreacted raw materials. Simultaneously, a suitable ratio helps control the selectivity of the reaction, avoiding side reactions caused by an excess of one reactant, thereby improving the purity and yield of intermediate I and providing high-quality raw materials for subsequent reactions.

[0028] 4. The molar ratio of intermediate I, diethylamine, and nitromethane in this invention is 1:2:2. This ratio is determined based on the reaction mechanism and the reactivity of the reactants. Diethylamine and nitromethane play different roles in the reaction; for example, diethylamine acts as a base or nucleophile, while nitromethane provides specific functional groups. The 1:2:2 molar ratio ensures sufficient contact opportunities between the reactants, balances the reaction rate, allows the reaction to reach a high conversion rate in a shorter time, and reduces the formation of byproducts, thereby improving the yield and purity of intermediate II.

[0029] 5. In this invention, the molar ratio of intermediate II, ammonium acetate, and boron trifluoride diethyl ether complex is 1:15:5. The ammonium acetate and boron trifluoride diethyl ether complex act as catalysts and reagents in the reaction. This 1:15:5 molar ratio provides sufficient reactive centers to promote the complete reaction of intermediate II, resulting in a more thorough reaction and improved yield of near-infrared II imaging materials. Furthermore, a suitable ratio can adjust the pH and coordination environment of the reaction system, which is beneficial for forming target products with specific structures and properties, and improving their optical properties and chemical stability.

[0030] 6. This invention uses Pluronic F-127 as a coating agent, with a mass ratio of Pluronic F-127 to the near-infrared II imaging material of 10:1. Pluronic F-127 is a commonly used amphiphilic polymer with good biocompatibility and stability. Using Pluronic F-127 as a coating agent at a mass ratio of 10:1 can form a stable coating layer on the surface of the near-infrared II imaging material, effectively preventing the aggregation of nanoparticles and improving their dispersibility and stability in vivo. Simultaneously, the appropriate coating ratio does not significantly affect the optical properties of the imaging material, ensuring that the nanoparticles still possess good near-infrared II imaging capabilities. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 These are the ultraviolet absorption and fluorescence emission spectra of NJ1040;

[0033] Figure 2 These are the ultraviolet absorption and fluorescence emission spectra of NJ1040 nanoparticles;

[0034] Figure 3 This is a transmission electron microscope image of NJ1040 nanoparticles;

[0035] Figure 4 This is a comparison chart of the NIR-II luminescence quantum yields of NJ1040 nanoparticles and ICG;

[0036] Figure 5 This is a comparison of the NIR-II imaging effects of NJ1040 nanoparticles and ICG in live mice. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] One near-infrared II imaging material is a nitrile boron pyrrole derivative, NJ1040, whose molecular structure is as follows:

[0039]

[0040] The preparation method of the above-mentioned near-infrared II imaging material (azafluoroboron pyrrole derivative) is as follows:

[0041] S1, 2-acetylthiophene was dissolved in ethanol to obtain a mixed solution, and then potassium hydroxide aqueous solution was slowly added to the mixed solution. After stirring, 4-diethylaminobenzaldehyde was added, and the mixture was stirred and extracted. The extracted organic phase was dried, concentrated by rotary evaporation, and then purified by silica gel column chromatography to obtain intermediate I.

[0042] S2, intermediate I, diethylamine and nitromethane are mixed, reacted and extracted, the extracted organic phase is dried, concentrated by rotary evaporation, and then purified by silica gel column chromatography to obtain intermediate II;

[0043] S3, intermediate II, ammonium acetate and ethanol are mixed and reacted, concentrated by rotary evaporation, and then triethylamine and boron trifluoride diethyl ether complex are added to continue the reaction and extraction; the extracted organic phase is dried, concentrated by rotary evaporation, and then purified by silica gel column chromatography to obtain the near-infrared II imaging material (azafluoroboron pyrrole derivative NJ1040).

[0044] In S1, the molar ratio of 2-acetylthiophene to 4-diethylaminobenzaldehyde is 1:1, the reaction temperature is room temperature (20-25℃), and the reaction time is 12 hours.

[0045] In S2, the molar ratio of intermediate I, diethylamine, and nitromethane is 1:2:2; the reaction temperature is 60℃, and the reaction time is 24 hours.

[0046] In S3, the molar ratio of intermediate II, ammonium acetate, and boron trifluoride diethyl ether complex is 1:15:5; the reaction temperature is room temperature, and the reaction time is 12 hours.

[0047] The method for preparing nanoparticles using the above-mentioned near-infrared II imaging material includes the following steps:

[0048] Step 1: Dissolve the azirmono-boron pyrrole derivative NJ1040 in tetrahydrofuran to obtain solution A; dissolve the coating agent in deionized water to obtain solution B;

[0049] Step 2: Perform sonication on solution B, then inject solution A into solution B, and sonicate intermittently to obtain the coating solution;

[0050] Step 3: Stir the coating solution obtained in Step 2 at a constant speed for 24 hours, and then concentrate it by ultrafiltration and centrifugation.

[0051] Step 4: Wash the concentrated product obtained in Step 3 multiple times to obtain nanoparticles (solution) of the azirmonoborone pyrrole derivative NJ1040.

[0052] The coating agent is Pluronic F-127, and the mass ratio of Pluronic F-127 to the azirmono-boron pyrrole derivative NJ1040 is 10:1.

[0053] In step 2, a cell disruptor is used to sonicate solution B with a power of not less than 130W for 45-60 seconds. After sonicating solution B, solution A is injected into solution B within 2 seconds using a syringe. Then, the cell disruptor is used again with a working cycle of 4 seconds followed by 1 second interval, and sonication is continued for 2-3 minutes to obtain the coating solution.

[0054] In step 3, the constant speed stirring speed is 600-1000 rpm.

[0055] The technical solution of the present invention will be described in detail below through the following embodiments. Where specific techniques or conditions are not specified in the embodiments, they are performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions; where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be obtained commercially.

[0056] Example 1

[0057] In this embodiment, the synthesis process of the azafluoroboron pyrrole derivative NJ1040 is described;

[0058] Step 1: Dissolve 2-acetylthiophene (2.5 g, 20 mmol) in ethanol (7 ml). Then, slowly add 20% potassium hydroxide aqueous solution (20 ml) to the solution at 0 °C. After stirring for 15 minutes, add 4-diethylaminobenzaldehyde (3.54 g, 20 mmol), and continue stirring the mixture at 0 °C for another 15 minutes. After cooling to room temperature, stir the reaction mixture overnight. Transfer the mixture to a separatory funnel and extract three times with dichloromethane. Dry the organic phase with anhydrous magnesium sulfate, concentrate the solvent using a rotary evaporator, and then purify by silica gel column chromatography using petroleum ether / ethyl acetate (40 / 1) as eluent to finally obtain intermediate I (4.5 g, 75%).

[0059] The proton NMR spectrum of intermediate I is as follows: 1 H NMR (400MHz, CDCl3) δ7.89–7.80(m,2H),7.64(dd,J=4.9,1.1Hz,1H),7.55(d,J=8.9Hz,2H ),7.26–7.17(m,2H),6.69(d,J=8.9Hz,2H),3.44(q,J=7.1Hz,4H),1.23(t,J=7.1Hz,6H). 13C NMR (101MHz, CDCl3) δ183.46,146.31,145.58,139.50,132.48,130.52,129.65,129.03,124.80,121.1,111.34,44.65,12.7.

[0060]

[0061] Step 2: A methanol solution (20 mL) of intermediate I (3.46 g, 10 mmol), diethylamine (20 mmol), and nitromethane (20 mmol) were added to a 100 mL two-necked flask and refluxed at 60 °C for 24 hours. After cooling to room temperature, the mixture was transferred to a separatory funnel and extracted three times with dichloromethane. The organic phase was dried over anhydrous magnesium sulfate, and the solvent was concentrated by rotary evaporation and further purified by silica gel column chromatography (eluent EA / PE = 1 / 4). The final product, intermediate II (2.3 g, yield: 82%), was obtained.

[0062] The proton NMR spectrum of intermediate II is as follows: 1 H NMR(400MHz, CDCl3) δ7.72(dd,J=3.8,1.1Hz,1H),7.66(dd,J=5.0,1.1Hz,1H),7.16–7.06(m,3H),6.62(d,J=8.8Hz,2H),4.80 (dd,J=12.3,6.9Hz,1H),4.66(dd,J=12.2,7.8Hz,1H),4.10(dd,J=14.2,7.3Hz,1H),3.43–3.28(m,6H),1.16(t,J=7.1Hz,6H). 13 C NMR (101MHz, CDCl3) δ190.36,147.38,144.13,134.48,132.52,129.03,128.65,124.80,111.88,79.98,44.34,42.58,38.85,12.65.

[0063]

[0064] Step 3: Intermediate II (1.38 g, 4 mmol) and ammonium acetate (4.62 g, 60 mmol) were dissolved in ethanol (50 ml) and refluxed at 80 °C for 48 hours. After cooling to room temperature, the solvent was concentrated by rotary evaporation to obtain a crude intermediate for the next step. After multiple vacuum-argon cycles for deoxygenation, the crude intermediate (0.6 g, 1 mmol) was dissolved in triethylamine (Et3N, 1 g, 1 mmol). After stirring at 0 °C for 20 minutes, boron trifluoride diethyl ether complex (BF3·Et2O, 2.84 g, 20 mmol) was added and stirring was continued at 0 °C for another 20 minutes. The mixture was then stirred overnight at room temperature. The reaction was terminated by adding ice water, and after stirring at room temperature for 1 hour and cooling to room temperature, the mixture was transferred to a separatory funnel and extracted three times with dichloromethane. After drying the organic phase with anhydrous magnesium sulfate, the solvent was concentrated by rotary evaporation and then further purified by silica gel column chromatography (eluent EA / DCM = 5 / 1) to finally obtain the dark blue solid product NJ1040 (0.12 g, 37%).

[0065] The proton NMR spectrum results for NJ1040 are as follows: 1 H NMR (400MHz, CDCl3) δ8.30 (d, J = 3.9Hz), 8.05 (d, J = 9.0Hz), 7.51 (d, J = 4.2Hz), 7.21 (dd ,J=5.0,4.0Hz),6.94(d,J=6.6Hz),6.72(d,J=9.1Hz),3.44(q,J=7.1Hz),1.59(s,12H). 13 C NMR (101MHz, CDCl3) δ148.38,145.48,142.52,134.83,131.72,131.21,129.75,129.48,120.16,114.20,111.28,53.51,44.67,12.74.MALDI-TOF: m / z calcd for C 36 H 36 BF2N5S2[M] + 651.247; Found: 651.423.

[0066]

[0067] Example 2

[0068] This embodiment describes the preparation process of NJ1040 nanoparticles; commercially available Pluronic F-127 is used as an encapsulating agent (i.e., nanocoating agent) to coat NJ1040, and the specific steps are as follows:

[0069] 1) Weigh 1 mg of NJ1040 on an analytical balance and place it in a centrifuge tube; measure 1 mL of tetrahydrofuran and inject it into the centrifuge tube, and sonicate it to ensure complete dissolution;

[0070] Weigh 10 mg of Pluronic F-127 using an analytical balance and place it in a sample vial. Add 10 mL of deionized water to the sample vial and sonicate for 1 hour to allow Pluronic F-127 to dissolve completely in the deionized water.

[0071] 2) Set the parameters for the cell disruptor: power 130W, work for 4 seconds, pause for 1 second.

[0072] After sonicating the Pluronic F-127 aqueous solution for 45 seconds using a cell disruptor, the fully dissolved NJ1040 was rapidly injected into the Pluronic F-127 aqueous solution within 2 seconds using a syringe, and sonicated for 2 minutes to obtain the coating solution.

[0073] 3) Wrap the sample vial containing the coating solution with aluminum foil to protect it from light, place it open on a magnetic stirrer at room temperature, keep the speed constant at 1000 rpm, and stir until the tetrahydrofuran in the coating solution is completely evaporated (usually takes more than 24 hours).

[0074] The coating solution is placed in an ultrafiltration centrifuge tube with a molecular weight cutoff of 30 kDa. During centrifugation, high molecular weight particles are retained by the filtration through the pore size of the ultrafiltration membrane, while water, solvent and low molecular weight solutes are allowed to permeate through the membrane, thereby achieving the purpose of concentration.

[0075] 4) After centrifugation once, wash three times with ultrapure water, then reduce the volume to 10 mL to obtain a nanoparticle solution with a NJ1040 mass concentration of 0.1 mg / mL. Store the solution in a refrigerator at 4°C. The transmission electron microscopy image is shown below. Figure 3 As shown, the particle size is approximately 45 nm.

[0076] Example 3

[0077] This embodiment describes the ultraviolet absorption spectroscopy test experiment of NJ1040 and NJ1040 nanoparticles;

[0078] 1) The ultraviolet absorption spectrum testing procedure for NJ1040 is as follows:

[0079] A 0.01 mg / mL NJ1040 solution was prepared using chromatographically pure tetrahydrofuran as the solvent. After the NJ1040 was fully dissolved, 2 mL of the solution was pipetted into a four-way quartz cuvette for later use. First, baseline calibration was performed on the four-way quartz cuvette containing spectrally pure tetrahydrofuran using a Shimadzu UV-3600PLUS UV-Vis-NIR spectrophotometer. After the above operations were completed, the cuvette containing the sample to be tested was placed in the cuvette, and its absorption spectrum in the range of 400–1100 nm was measured.

[0080] Test results are as follows Figure 1 As shown, it can be seen that the maximum absorption peak of NJ1040 is at 810 nm.

[0081] 2) The UV absorption spectroscopy test method for NJ1040 nanoparticles is the same as that for NJ1040; except that the sample to be tested is replaced by NJ1040 nanoparticles instead of NJ1040, and the solvent is replaced by deionized water instead of chromatographically pure tetrahydrofuran.

[0082] Its ultraviolet absorption spectrum is as follows Figure 2 As shown, the NJ1040 nanoparticles exhibit a maximum absorption peak at 810 nm. This indicates that the maximum absorption peak of the coated NJ1040 nanoparticles remains essentially unchanged compared to NJ1040.

[0083] Example 4

[0084] This embodiment describes the fluorescence emission spectroscopy test experiment of NJ1040 and NJ1040 nanoparticles.

[0085] 1) The fluorescence emission spectroscopy test procedure for NJ1040 is as follows:

[0086] A 0.01 mg / mL NJ1040 solution was prepared using chromatographically pure tetrahydrofuran as the solvent. After thoroughly dissolving the NJ1040, 2 mL of the solution was pipetted into a four-way quartz cuvette for later use. (The last sentence appears to be incomplete and possibly refers to using HORIBA.) The fluorescence emission spectrum of the sample solution was measured using a fluorescence spectrometer. The excitation wavelength was selected as 808 nm, the slit size as 5 × 5 mm, the excitation voltage as 650 V, and the measurement range as 830–1250 nm. The test results are as follows: Figure 1 As shown, the maximum fluorescence emission peak of NJ1040 appears at 953 nm.

[0087] The fluorescence emission spectroscopy test method for NJ1040 nanoparticles was the same as above, except that the sample was replaced with NJ1040 nanoparticles, and the solvent was changed from chromatographically pure tetrahydrofuran to deionized water. The fluorescence emission spectrum is shown below. Figure 2As shown, the maximum emission peak of NJ1040 nanoparticles appears at 932 nm, indicating that the maximum emission peak of NJ1040 nanoparticles after coating is significantly blue-shifted compared to NJ1040.

[0088] Example 5

[0089] This embodiment describes the fluorescence quantum yield test experiment of NJ1040 nanoparticles and ICG.

[0090] IR1061 (with a quantum yield of 1.7% in dichloromethane solvent) was selected as the standard. Five IR1061 solutions were prepared using deionized water and measured using a Shimadzu UV-3600PLUS UV-Vis-NIR spectrophotometer, with absorbances at 808 nm of approximately 0.1, 0.08, 0.06, 0.04, and 0.02. Near-infrared emission spectra of five solutions were detected using a fluorescence spectrometer, with a detection range of 850–1500 nm. The same absorption and emission measurements were performed on NJ1040 nanoparticles and ICG. The integrated fluorescence intensity was plotted against the absorbance at 808 nm and fitted as a linear function, with the fluorescence quantum yield QY... sample Calculated using the following formula:

[0091]

[0092] Among them, QY ref It is 1.7%, n sample n is the refractive index of the solvent (water in this example) in the sample solution. ref It is the refractive index of the solvent (dichloromethane (DCM) in the standard solution), slope sample It is the slope of the calibrated fluorescence intensity-absorbance curve of the sample. ref It is the slope of the calibrated fluorescence intensity-absorbance curve of the standard.

[0093] Test results are as follows Figure 4 ,in, Figure 4 (a) in the figure is the fluorescence quantum yield diagram of IR26. Figure 4 (b) in the figure is the fluorescence quantum yield diagram of NJ1040 nanoparticles. Figure 4 (c) in the figure shows the fluorescence quantum yield of ICG. Calculations show that the fluorescence quantum efficiency of NJ1040 nanoparticles is 5.68%, while that of ICG is 1.38%. Therefore, it can be concluded that the quantum efficiency of NJ1040 nanoparticles is much higher than that of commercial ICG, resulting in better imaging performance.

[0094] Example 6

[0095] This embodiment describes the application of NJ1040 nanoparticles in bioimaging.

[0096] Two mice were used. Hair was removed to eliminate interference. 200 μL of a 1 mg / mL NJ1040 nanoparticle solution was injected into the tail vein. After anesthetizing the mice with isoflurane (2% concentration), NIR-II imaging was immediately performed on the mice's entire vascular network (vascular imaging could be performed immediately after anesthesia and up to three hours post-anesthesia), particularly focusing on clear NIR-II fluorescence imaging of the microvessels in the chest and hind limbs. An 808 nm laser was used as the light source, and a 1500 nm long-pass filter was selected to observe the blood vessels in the mouse legs and abdomen.

[0097] The results are as follows Figure 5 As shown, where, Figure 5 Image (a) is an image of the blood vessels in the left hind limb of a mouse after intravenous injection of 1040 nanoparticles. Figure 5 Image (b) is an vascular imaging image of the left hind limb of a mouse that has been intravenously injected with ICG. Figure 5 As can be seen, after intravenous injection of 1040NPs, imaging of the blood vessels in the left hind limb using 808nm excitation yielded a high signal-to-noise ratio of 3.65, demonstrating a significant advantage in accumulating diagnostic information. Furthermore, NJ1040NPs also exhibited excellent passive accumulation capabilities and good biocompatibility at tumor sites, which is beneficial for practical biological applications.

[0098] The above embodiments and test examples demonstrate that the NJ1040 nanoparticles described in this invention, compared to the commonly used dye indocyanine green (ICG), have greater imaging depth, better spatial resolution, and a higher signal-to-noise ratio; imageJ software was used to... Figure 5 Analysis revealed that the signal-to-noise ratio of NJ1040 nanoparticles was as high as 3.65, while that of the commercial dye ICG was only 1.89.

[0099] This demonstrates that NJ1040 nanoparticles have better imaging performance than ICG and are a better near-infrared II imaging material.

[0100] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0101] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A near-infrared II imaging material, characterized in that, NJ1040 is a azirmonoborone pyrrole derivative with the following molecular structure:

2. The method for preparing a near-infrared II imaging material according to claim 1, characterized in that, Includes the following steps: 2-Acetylthiophene was dissolved in ethanol to obtain a mixed solution. Potassium hydroxide aqueous solution was added and stirred. Then 4-diethylaminobenzaldehyde was added, stirred, and extracted. The extracted organic phase was dried, concentrated by rotary evaporation, and purified to obtain intermediate I. Intermediate I, diethylamine and nitromethane were mixed, reacted and extracted. The extracted organic phase was dried, concentrated and purified by rotary evaporation to obtain intermediate II. Intermediate II, ammonium acetate, and ethanol were mixed and reacted, concentrated by rotary evaporation, and then triethylamine and boron trifluoride diethyl ether complex were added to continue the reaction and extraction. The extracted organic phase was dried, concentrated by rotary evaporation, and purified to obtain the near-infrared II imaging material.

3. The method for preparing a near-infrared II imaging material according to claim 2, characterized in that, The molar ratio of 2-acetylthiophene to 4-diethylaminobenzaldehyde is 1:

1.

4. The method for preparing a near-infrared II imaging material according to claim 2, characterized in that, The molar ratio of intermediate I, diethylamine, and nitromethane is 1:2:

2.

5. The method for preparing a near-infrared II imaging material according to claim 2, characterized in that, The molar ratio of intermediate II, ammonium acetate, and boron trifluoride diethyl ether complex is 1:15:

5.

6. The application of the near-infrared II imaging material according to claim 1 in bioimaging.

7. A method for preparing near-infrared II imaging material nanoparticles, characterized in that, Includes the following steps: The near-infrared II imaging material according to claim 1 is dissolved in tetrahydrofuran to obtain solution A; The coating agent was dissolved in deionized water to obtain solution B; Solution B was subjected to sonication, and then solution A was injected into solution B. The sonication was continued intermittently to obtain a coating solution. After stirring the coating solution, ultrafiltration centrifugation and concentration were performed; then the concentrated product was washed to obtain near-infrared II imaging material nanoparticles.

8. The method for preparing near-infrared II imaging material nanoparticles according to claim 7, characterized in that, The coating agent is Pluronic F-127, and the mass ratio of Pluronic F-127 to the near-infrared II imaging material is 10:

1.

9. A near-infrared II imaging material nanoparticle, characterized in that, It was prepared using the method for preparing near-infrared II imaging material nanoparticles as described in claim 7 or 8.

10. The application of the near-infrared II imaging material nanoparticles of claim 9 as a contrast agent in bioimaging, wherein the application is for non-diagnostic purposes.

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