A kind of ultra-small high-performance near-infrared long-afterglow nanoparticles and their preparation method and application

Abstract

The present invention discloses an ultra-small and high-performance near-infrared long afterglow nanoparticle and its preparation method and application. The preparation method includes the following steps: S1. Gallium acetylacetonate, zinc acetylacetonate, chromium acetylacetonate and a long-chain alkyl diol are added to a mixed solution containing oleic acid, oleylamine and octadecene, stirred, evacuated, and heated to 50-110 °C, and the long-chain alkyl diol contains 10-18 carbon atoms; S2. Under nitrogen protection, the temperature is raised to 160-240 °C and kept warm; S3. The temperature is continuously raised to 260-340 °C, kept warm, and post-treated to obtain the ultra-small and high-performance near-infrared long afterglow nanoparticle. The average diameter of the ultra-small and high-performance near-infrared long afterglow nanoparticle prepared by the present invention is below 5 nanometers, and at the same time has an excellent long afterglow luminescence duration, and has broad application prospects in the fields of optical imaging and biomedical diagnosis and treatment reagent development.

Description

Technical Field

[0001] The present invention belongs to the technical field of near-infrared long afterglow nanomaterials, and more specifically, relates to an ultra-small and high-performance near-infrared long afterglow nanoparticle, a preparation method thereof, and an application thereof. Background Art

[0002] The long afterglow luminescent material is a luminescent material that can still continuously emit light for a long time after the excitation stops. By virtue of its unique ultra-long lifetime luminescence, the near-infrared long afterglow luminescent material can be excited in vitro and then enter the living body for imaging. Compared with traditional quantum dots and upconversion luminescent materials, the near-infrared long afterglow luminescent material can be excited in vitro, avoiding the background fluorescence interference of biological tissues caused by continuous excitation. At the same time, the emission of near-infrared light is in the biological optical window and has strong penetration. Therefore, the near-infrared long afterglow luminescent material has the advantage of ultra-high signal-to-noise ratio in the application of biological in vivo optical imaging and shows great application prospects.

[0003] The existing preparation strategies for near-infrared long afterglow luminescent materials mainly include high-temperature solid-phase method, sol-gel method, hydrothermal method, and silica template method. Among them, the near-infrared long afterglow luminescent material prepared by the high-temperature solid-phase method has a large particle size and is not suitable for biological in vivo imaging; while the sol-gel method and the hydrothermal method can obtain near-infrared long afterglow luminescent nanomaterials with a particle size less than 100 nm, but the prepared nanoparticles often agglomerate very much and are likely to highly accumulate in organs such as the liver, spleen, and lung, which not only leads to high background signals but also causes potential toxicity to these organs, restricting their applications in the fields of in vivo imaging and cell tracing. The particle size of the near-infrared long afterglow luminescent material prepared by the silica template method depends on the size of the silica template, and currently, the application of this method cannot be realized in a silica template with a size less than 50 nm.

[0004] Multiple studies have shown that near-infrared long afterglow luminescent nanomaterials with a particle size less than 5 nm can be excreted through the kidneys and have higher metabolic efficiency. Therefore, in theory, near-infrared long afterglow luminescent materials with a particle size less than 5 nm will have smaller background interference and higher biological safety. However, as the particle size of the nanomaterials gradually becomes smaller, their luminescent performance generally gradually weakens. Therefore, how to explore a near-infrared long afterglow luminescent nanomaterial with a smaller particle size but better long afterglow continuous luminescence time has become an important problem that needs to be solved urgently.

[0005] Patent Publication No. CN105754595A discloses a long afterglow nanomaterial. A zinc nitrate solution, a gallium nitrate solution, a sodium germanate solution, and a chromium nitrate solution are mixed and stirred, and ammonia water is quickly added to adjust the pH of the mixed solution to 10. Then, the mixed solution is transferred to a high-temperature hydrothermal autoclave and reacted at 120 °C for 24 h. The prepared long afterglow material has uniform size, and the size can be increased from 7 nm to 80 nm, and it produces high brightness and long duration under visible light excitation. However, when the composition of the prepared long afterglow nanomaterial is ZnGa2O4: 0.75% Cr, the particle size is 7 nm, and in the afterglow decay image, its afterglow time is only 3 h, still difficult to meet the actual application requirements. Summary of the Invention

[0006] In view of the above existing technical problems, the primary object of the present invention is to provide a method for preparing ultra-small high-performance near-infrared long afterglow nanoparticles. The average diameter of the prepared near-infrared long afterglow nanoparticles is less than 5 nm, and it can produce near-infrared long afterglow emission with a wavelength between 600 nm and 800 nm, and the longest duration of the long afterglow luminescence can exceed 5 hours.

[0007] The second object of the present invention is to provide ultra-small high-performance near-infrared long afterglow nanoparticles prepared by a method for preparing ultra-small high-performance near-infrared long afterglow nanoparticles.

[0008] The third object of the present invention is to provide the application of ultra-small high-performance near-infrared long afterglow nanoparticles in biological in vivo optical imaging, molecular labeling, or in the preparation of medical diagnosis and treatment reagents.

[0009] To achieve the above objects, the present invention is realized by the following technical solutions:

[0010] The present invention claims a method for preparing ultra-small high-performance near-infrared long afterglow nanoparticles, comprising the following steps:

[0011] S1. Gallium acetylacetonate, zinc acetylacetonate, chromium acetylacetonate, and long-chain alkyl diol are added to a mixed solution containing oleic acid, oleylamine, and octadecene, stirred, evacuated, heated to 50 - 110 °C, and kept warm; the long-chain alkyl diol contains 10 - 18 carbon atoms;

[0012] S2. Under nitrogen protection, the temperature is raised to 160 - 240 °C and kept warm;

[0013] S3. The temperature is further raised to 260 - 340 °C, kept warm, and post-treated to obtain the ultra-small high-performance near-infrared long afterglow nanoparticles.

[0014] The present invention uses a mixed solvent of oleic acid, oleylamine and octadecene as the reaction system, which not only restricts the grain growth of the near-infrared long afterglow nanoparticles, but also improves the dispersibility of the nanoparticles by using the organic groups attached to the particle surface. The prepared nanoparticles not only have a smaller particle size, but also reduce the agglomeration of the nanoparticles. The introduction of long-chain alkyl diol can promote the decomposition of the acetylacetonate raw material, improve the crystallinity of the near-infrared long afterglow nanoparticles, and thus enhance the near-infrared long afterglow luminescence performance. If a short-chain alkyl diol with a low boiling point is introduced into the reaction system, the heating temperature in step S3 cannot be raised to the optimal reaction temperature, and the ultra-small and high-performance near-infrared long afterglow nanoparticles of the present invention cannot be prepared.

[0015] Furthermore, the present invention uses a three-stage heating method to prepare the ultra-small and high-performance near-infrared long afterglow nanoparticles. The purpose of the first-stage heating is to completely dissolve the acetylacetonate in the mixed solvent of oleic acid, oleylamine and octadecene; the purpose of the second-stage heating is to promote the decomposition of the acetylacetonate to form small grains; and the purpose of the third-stage heating is to help the grains grow, and finally the high-performance infrared long afterglow nanoparticles are prepared. The long afterglow nanoparticles prepared by the present invention not only have a smaller average diameter, but also have a more excellent long afterglow luminescence duration.

[0016] Preferably, in the step S1, the molar ratio of gallium acetylacetonate, zinc acetylacetonate, chromium acetylacetonate and long-chain diol is 2:(0.6-1.4):(1×10 -4 -2×10 -3 ):(1-40). Further preferably, the molar ratio of gallium acetylacetonate, zinc acetylacetonate, chromium acetylacetonate and long-chain diol is 2:(1.0-1.1):(1×10 -3 -1.5×10 -3 ):(5-15). Further preferably, the molar ratio of gallium acetylacetonate, zinc acetylacetonate, chromium acetylacetonate and long-chain diol is 2:1:1.42×10 -3 :10. Under the above preferred ranges, the prepared ultra-small and high-performance near-infrared long afterglow nanoparticles have a higher luminescence intensity.

[0017] Preferably, in the step S1, the volume ratio of oleic acid, oleylamine and octadecene is 1:(0.5-1.5):(1-4). Further preferably, the volume ratio of oleic acid, oleylamine and octadecene is 1:(0.8-1.2):(1.5-2.5).

[0018] Specifically, the long-chain alkyl diol in the present invention may contain 10 carbon atoms, 11 carbon atoms, 12 carbon atoms, 13 carbon atoms, 14 carbon atoms, 15 carbon atoms, 16 carbon atoms, 17 carbon atoms, 18 carbon atoms, etc., or an interval range formed by any of the above values, such as 10 to 14 carbon atoms, 12 to 18 carbon atoms, etc. The present invention is not limited thereto.

[0019] Preferably, the long-chain alkyl diol contains 12 to 16 carbon atoms. Further preferably, the long-chain alkyl diol is selected from one or more of 1,2-dodecanediol, 1,2-tetradecanediol, or 1,2-hexadecanediol. Further preferably, the long-chain alkyl diol is 1,2-tetradecanediol.

[0020] Preferably, in step S2, the heat preservation time is 0.5 to 3 h. Further preferably, the heat preservation time is 0.8 to 1.5 h.

[0021] Specifically, in step S2, under nitrogen protection, the temperature is raised to 160 °C, 170 °C, 180 °C, 190 °C, 200 °C, 210 °C, 220 °C, 230 °C, 240 °C, etc., or an interval range formed by any of the above values, such as 160 °C to 190 °C, 170 °C to 210 °C, etc. The present invention is not limited thereto. Further preferably, in step S2, the temperature is raised to 180 to 220 °C.

[0022] Preferably, in step S3, the heat preservation time is 0.5 to 5 h. Further preferably, the heat preservation time is 1 to 3 h.

[0023] Specifically, in step S3, the temperature is further raised to 260 °C, 270 °C, 280 °C, 290 °C, 300 °C, 310 °C, 320 °C, 330 °C, 340 °C, etc., or an interval range formed by any of the above values, such as 260 °C to 290 °C, 270 °C to 310 °C, etc. The present invention is not limited thereto. Further preferably, in step S3, the temperature is further raised to 290 to 320 °C.

[0024] Preferably, in step S1, the heat preservation time is 0.4 to 2 h. Further preferably, the heat preservation time is 0.6 to 1 h.

[0025] Further preferably, in step S1, the temperature is raised to 70 to 90 °C.

[0026] Preferably, the post-treatment includes centrifugation, resuspension, and washing.

[0027] Furthermore, the present invention claims the ultra-small high-performance near-infrared long afterglow nanoparticles prepared by the preparation method of the above ultra-small high-performance near-infrared long afterglow nanoparticles.

[0028] Preferably, the average diameter of the ultra-small high-performance near-infrared long afterglow nanoparticles is less than 5 nm. More preferably, the average diameter of the ultra-small high-performance near-infrared long afterglow nanoparticles is 3.5 - 4.5 nm.

[0029] Preferably, the chemical formula of the ultra-small high-performance near-infrared long afterglow nanoparticles is Zn y Ga2Cr x O4, where 1×10 -4 ≤x≤2×10 -3 , 0.6≤y≤1.4. Among them, Zn y Ga2O4 is the matrix, and Cr 3+ is the activator ion. Preferably, 0.0005≤x≤0.002, 0.8≤y≤1.2. More preferably, 0.001≤x≤0.0015, 1.0≤y≤1.1.

[0030] Furthermore, the present invention claims protection for the application of the ultra-small high-performance near-infrared long afterglow nanoparticles in in vivo optical imaging, molecular labeling, or in the preparation of medical diagnostic and therapeutic reagents.

[0031] The ultra-small high-performance near-infrared long afterglow nanoparticles provided by the present invention have an average diameter of less than 5 nanometers and a long afterglow luminescence property with a luminescence duration exceeding 4 hours. After appropriate functionalization modification, the nanoparticles can also be used in fields such as sub-organelle imaging, molecular labeling, and in vivo fine optical imaging. Therefore, the applications in the above fields should also be within the protection scope of the present invention.

[0032] Compared with the prior art, the present invention has the following beneficial effects:

[0033] The present invention provides a preparation method of ultra-small high-performance near-infrared long afterglow nanoparticles. The method uses a mixed solution of oleic acid, oleylamine, and octadecene as the reaction medium and long-chain diol as the reaction regulation reagent. By using specific regulated amounts of zinc acetylacetonate and chromium acetylacetonate, as well as the reaction temperature and time, ultra-small high-performance near-infrared long afterglow nanoparticles with an average diameter below 5 nanometers and good dispersibility are prepared, which can effectively avoid high aggregation in organs such as the liver, spleen, and lungs. At the same time, the nanoparticles also have excellent long afterglow luminescence properties, can be effectively excited by 265-nm ultraviolet light, produce near-infrared long afterglow emission with wavelengths between 600 nm and 800 nm, and the maximum long afterglow luminescence duration exceeds 5 hours, enabling better in vivo imaging effects and having broad application prospects in the fields of optical imaging and biomedical diagnostic and therapeutic reagent development. Description of the Drawings

[0034] Figure 1TEM image of the ultra-small high-performance near-infrared long afterglow nanoparticles provided for Example 1.

[0035] Figure 2 Particle size distribution diagram of the ultra-small high-performance near-infrared long afterglow nanoparticles provided for Example 1.

[0036] Figure 3 XRD pattern of the ultra-small high-performance near-infrared long afterglow nanoparticles provided for Example 1.

[0037] Figure 4 Excitation and emission spectrum diagram of the ultra-small high-performance near-infrared long afterglow nanoparticles provided for Example 1, where the dashed line is the excitation spectrum and the solid line is the emission spectrum.

[0038] Figure 5 Emission spectrum diagrams of ultra-small high-performance near-infrared long afterglow nanoparticles with different Zn 2+ contents provided for Examples 1 to 5.

[0039] Figure 6 Emission spectrum diagrams of ultra-small high-performance near-infrared long afterglow nanoparticles with different Cr 3+ contents provided for Example 1 and Examples 6 to 10.

[0040] Figure 7 Emission spectrum diagrams of ultra-small high-performance near-infrared long afterglow nanoparticles prepared by adding different contents of 1,2-tetradecanediol provided for Comparative Example 1, Example 1 and Examples 11 to 14.

[0041] Figure 8 Emission spectrum diagrams of ultra-small high-performance near-infrared long afterglow nanoparticles prepared at different reaction temperatures provided for Example 1 and Examples 15 to 19.

[0042] Figure 9 Long afterglow luminescence decay curve diagram and long afterglow emission spectrum diagram of the ultra-small high-performance near-infrared long afterglow nanoparticles provided for Example 1.

[0043] Figure 10 TEM images and afterglow decay imaging diagrams of ultra-small high-performance near-infrared long afterglow nanoparticles prepared by adding different contents of 1,2-tetradecanediol provided for Example 1 and Examples 11 to 14. Detailed implementation mode

[0044] The present invention will be further described below in conjunction with the accompanying drawings of the specification and specific examples, but the examples do not limit the present invention in any form. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the technical field.

[0045] Example 1 Preparation method of ultra-small high-performance near-infrared long afterglow nanoparticles

[0046] (1) Gallium acetylacetonate, zinc acetylacetonate, chromium acetylacetonate and 1,2-tetradecanediol (molar ratio 2:1:0.00142:10) were added to a three-necked flask containing a mixed solution of 10 mL of oleic acid, 10 mL of oleylamine and 20 mL of octadecene. While stirring and under vacuum, it was heated to 80 °C and kept warm for 0.5 hour.

[0047] (2) The reaction product of step (1) was heated to 200 °C under nitrogen protection and kept warm for 1 hour.

[0048] (3) It was further heated to 310 °C and kept warm for 2 hours.

[0049] (4) The reaction product of step (3) was cooled. After multiple centrifugations, resuspensions and washings, ultra-small high-performance near-infrared long afterglow nanoparticles were obtained.

[0050] Examples 2 to 5 A method for preparing ultra-small high-performance near-infrared long afterglow nanoparticles

[0051] The difference between Example 2 and Example 1 is that the molar ratio of gallium acetylacetonate, zinc acetylacetonate, chromium acetylacetonate and 1,2-tetradecanediol is 2:0.8:0.00142:10.

[0052] The difference between Example 3 and Example 1 is that the molar ratio of gallium acetylacetonate, zinc acetylacetonate, chromium acetylacetonate and 1,2-tetradecanediol is 2:0.9:0.00142:10.

[0053] The difference between Example 4 and Example 1 is that the molar ratio of gallium acetylacetonate, zinc acetylacetonate, chromium acetylacetonate and 1,2-tetradecanediol is 2:1.1:0.00142:10.

[0054] The difference between Example 5 and Example 1 is that the molar ratio of gallium acetylacetonate, zinc acetylacetonate, chromium acetylacetonate and 1,2-tetradecanediol is 2:1.2:0.00142:10.

[0055] Examples 6 to 10 A method for preparing ultra-small high-performance near-infrared long afterglow nanoparticles

[0056] The difference between Example 6 and Example 1 is that the molar ratio of gallium acetylacetonate, zinc acetylacetonate, chromium acetylacetonate and 1,2-tetradecanediol is 2:1:0.00058:10.

[0057] The difference between Example 7 and Example 1 is that the molar ratio of gallium acetylacetonate, zinc acetylacetonate, chromium acetylacetonate and 1,2-tetradecanediol is 2:1:0.00086:10.

[0058] Example 8 is different from Example 1 in that the molar ratio of gallium acetylacetonate, zinc acetylacetonate, chromium acetylacetonate and 1,2-tetradecanediol is 2:1:0.00114:10.

[0059] Example 9 is different from Example 1 in that the molar ratio of gallium acetylacetonate, zinc acetylacetonate, chromium acetylacetonate and 1,2-tetradecanediol is 2:1:0.00172:10.

[0060] Example 10 is different from Example 1 in that the molar ratio of gallium acetylacetonate, zinc acetylacetonate, chromium acetylacetonate and 1,2-tetradecanediol is 2:1:0.002:10.

[0061] Examples 11 to 14 A method for preparing ultra-small high-performance near-infrared long afterglow nanoparticles

[0062] Example 11 is different from Example 1 in that the molar ratio of gallium acetylacetonate, zinc acetylacetonate, chromium acetylacetonate and 1,2-tetradecanediol is 2:1:0.00142:2.

[0063] Example 12 is different from Example 1 in that the molar ratio of gallium acetylacetonate, zinc acetylacetonate, chromium acetylacetonate and 1,2-tetradecanediol is 2:1:0.00142:5.

[0064] Example 13 is different from Example 1 in that the molar ratio of gallium acetylacetonate, zinc acetylacetonate, chromium acetylacetonate and 1,2-tetradecanediol is 2:1:0.00142:15.

[0065] Example 14 is different from Example 1 in that the molar ratio of gallium acetylacetonate, zinc acetylacetonate, chromium acetylacetonate and 1,2-tetradecanediol is 2:1:0.00142:20.

[0066] Examples 15 to 19 A method for preparing ultra-small high-performance near-infrared long afterglow nanoparticles

[0067] Example 15 is different from Example 1 in that in step (3), the temperature is further raised to 290 °C.

[0068] Example 16 is different from Example 1 in that in step (3), the temperature is further raised to 300 °C.

[0069] Example 17 is different from Example 1 in that in step (3), the temperature is further raised to 320 °C.

[0070] Example 18 is different from Example 1 in that in step (3), the temperature is further raised to 330 °C.

[0071] Example 19 is different from Example 1 in that in step (3), the temperature is further raised to 340 °C.

[0072] Comparative Example 1

[0073] The difference between Comparative Example 1 and Example 1 lies in that the molar ratio of gallium acetylacetonate, zinc acetylacetonate, chromium acetylacetonate and 1,2-tetradecanediol is 2:1:0.00142:0, that is, 1,2-tetradecanediol was not added in Comparative Example 1.

[0074] Characterization and performance testing of ultra-small high-performance near-infrared long afterglow nanoparticles in Test Example 1

[0075] The ultra-small high-performance near-infrared long afterglow nanoparticles prepared in Example 1 were dissolved in a cyclohexane solution, dropped on a copper grid, and the morphology and size of the nanoparticles were observed by transmission electron microscopy. Figure 1 This is the TEM image of the ultra-small high-performance near-infrared long afterglow nanoparticles provided in Example 1. From Figure 1 it can be seen that the ultra-small high-performance near-infrared long afterglow nanoparticles with an average diameter of less than 5 nm were successfully prepared in Example 1, and they have excellent dispersibility.

[0076] Figure 2 This is the size distribution diagram of the ultra-small high-performance near-infrared long afterglow nanoparticles provided in Example 1 (200 nanoparticles were randomly selected for statistics). From Figure 2 it can be seen that the average size of the ultra-small high-performance near-infrared long afterglow nanoparticles prepared in Example 1 is 3.76 nm.

[0077] The ultra-small high-performance near-infrared long afterglow nanoparticles prepared in Example 1 were measured by an X-ray powder diffractometer. Figure 3 This is the XRD pattern of the ultra-small high-performance near-infrared long afterglow nanoparticles provided in Example 1. From Figure 3 it can be seen that the XRD pattern of the prepared ultra-small high-performance near-infrared long afterglow nanoparticles is consistent with the standard card of ZnGa2O4 (JCPDS: 38-1240), and it is a pure phase.

[0078] The ultra-small high-performance near-infrared long afterglow nanoparticles prepared in Example 1 were measured by a fluorescence spectrometer. Figure 4 This is the excitation and emission spectrum of the ultra-small high-performance near-infrared long afterglow nanoparticles provided in Example 1. From Figure 4 it can be seen that the emission band of the nanoparticles is between 600 nm and 800 nm, and the main emission peak is at 695 nm.

[0079] The ultra-small high-performance near-infrared long afterglow nanoparticles prepared in each example and comparative example were measured by a fluorescence spectrometer.

[0080] Figure 5 For Examples 1 to 5 with different Zn 2+Emission spectrum of ultra-small high-performance near-infrared long afterglow nanoparticles with different contents. From Figure 5 it can be seen that as the content of Zn 2+ increases, the luminescence intensity of the nanoparticles shows a trend of first increasing and then decreasing. When the molar ratio of gallium acetylacetonate, zinc acetylacetonate, chromium acetylacetonate and 1,2-tetradecanediol is 2:1:0.00142:10, the optical properties of the nanoparticles are the best.

[0081] Figure 6 Emission spectra of ultra-small high-performance near-infrared long afterglow nanoparticles with different Cr 3+ contents provided in Example 1 and Examples 6-10. From Figure 6 it can be seen that as the content of Cr 3+ increases, the luminescence intensity of the nanoparticles shows a trend of first increasing and then decreasing. When the molar ratio of gallium acetylacetonate, zinc acetylacetonate, chromium acetylacetonate and 1,2-tetradecanediol is 2:1:0.00142:10, the optical properties of the nanoparticles are the best.

[0082] Figure 7 Emission spectra of ultra-small high-performance near-infrared long afterglow nanoparticles prepared by adding different contents of 1,2-tetradecanediol provided in Comparative Example 1, Example 1 and Examples 11-14. From Figure 7 it can be seen that as the addition amount of 1,2-tetradecanediol increases, the luminescence intensity of the nanoparticles shows a trend of first increasing and then decreasing. When the addition amount of 1,2-tetradecanediol is 10 mmol, the optical properties of the nanoparticles are the best. Therefore, the optimal addition amount of 1,2-tetradecanediol is selected as 10 mmol.

[0083] Figure 8 Emission spectra of ultra-small high-performance near-infrared long afterglow nanoparticles prepared at different reaction temperatures provided in Example 1 and Examples 15-19. From Figure 8 it can be seen that as the reaction temperature increases, the luminescence intensity of the nanoparticles shows a trend of first increasing and then decreasing. When the reaction temperature is 310 °C, the optical properties of the nanoparticles are the best. Therefore, the optimal reaction temperature is selected as 310 °C.

[0084] The long afterglow luminescence test was carried out on the ultra-small high-performance near-infrared long afterglow nanoparticles prepared in Example 1. The specific operation is as follows: After irradiating the nanoparticles with 265-nm ultraviolet light for 1 minute, the afterglow intensity of the nanoparticles was measured by a small animal optical imaging system to obtain a long afterglow luminescence decay curve; After irradiating the nanoparticles with 265-nm ultraviolet light for 1 minute, it was immediately measured by a fluorescence spectrometer to obtain a long afterglow emission spectrum.

[0085] Figure 9The long afterglow luminescence decay curve and long afterglow emission spectrum of the ultra-small high-performance near-infrared long afterglow nanoparticles provided for Example 1. From Figure 9 it can be seen that the long afterglow emission spectrum of the nanoparticles is basically consistent with the Figure 1 emission spectrum in terms of spectral shape. The afterglow emission band is between 600 nm and 800 nm, the main emission peak is slightly shifted and located at 705 nm, and the long afterglow luminescence duration exceeds 5 hours.

[0086] Figure 10 The TEM images and afterglow decay imaging diagrams of the ultra-small high-performance near-infrared long afterglow nanoparticles prepared with different contents of 1,2-tetradecanediol provided for Example 1 and Examples 11 to 14. The average diameters and long afterglow luminescence durations of the ultra-small high-performance near-infrared long afterglow nanoparticles prepared in Example 1 and Examples 11 to 14 are shown in Table 1 below.

[0087] Table 1

[0088] Average diameter (nm) Persistent afterglow duration (h) Example 1 3.76 5 Example 11 4.09 4 Example 12 3.69 4 Example 13 3.84 4 Example 14 4.14 4

[0089] From Figure 10 and Table 1, it can be seen that the average diameter of the ultra-small high-performance near-infrared long afterglow nanoparticles provided by the present invention is less than 5 nm, and the long afterglow luminescence duration of all of them exceeds 4 h. Among them, the long afterglow luminescence duration of the ultra-small high-performance near-infrared long afterglow nanoparticles prepared in Example 1 exceeds 5 hours.

[0090] The foregoing examples are illustrative only and are used to explain some features of the method of the present invention. The appended claims are intended to claim the broadest scope conceivable, and the examples presented herein are demonstrated by the applicant's actual test results. Therefore, the applicant's intention is that the appended claims should not be limited by the selection of examples that illustrate the features of the present invention. Some of the numerical ranges used in the claims also include sub-ranges within them, and variations within these ranges should also be construed as being covered by the appended claims where possible.

Claims

1. A method for preparing ultra-small high-performance near-infrared long-afterglow nanoparticles, characterized in that: The following steps are involved: S1. Gallium acetylacetonate, zinc acetylacetonate, chromium acetylacetonate and a long-chain alkyl glycol are added to a mixed solution containing oleic acid, oleylamine and octadecene, stirred, evacuated, heated to 50 to 110° C., and kept warm; the long-chain alkyl glycol contains 10 to 18 carbon atoms; S2. Raise the temperature to 160-240°C under nitrogen protection and keep warm; S3. Continue to heat to 260-340°C, keep warm, and post-treat to obtain the ultra-small high-performance near-infrared long afterglow nanoparticles; In the step S1, the molar ratio of gallium acetylacetonate, zinc acetylacetonate, chromium acetylacetonate and long-chain alkyl glycol is 2:(0.6-1.4):(1×10 -4 ~2×10 -3 ): (1~40); The average diameter of ultra-small high-performance near-infrared long afterglow nanoparticles is 3.5 to 4.5 nm.

2. The preparation method according to claim 1, characterized in that: In the step S1, the volume ratio of oleic acid, oleylamine and octadecene is 1:(0.5-1.5):(1-4).

3. The preparation method according to claim 1, characterized in that: The long chain alkyl glycol contains 12 to 16 carbon atoms.

4. The preparation method according to claim 1, characterized in that: In step S2, the insulation time is 0.5 to 3 hours.

5. The preparation method according to claim 1, characterized in that: In step S3, the insulation time is 0.5 to 5 hours.

6. Ultra-small high-performance near-infrared long afterglow nanoparticles prepared by the preparation method according to any one of claims 1 to 5.

7. The ultra-small high-performance near-infrared long afterglow nanoparticles according to claim 6, characterized in that: The chemical formula of the ultra-small high-performance near-infrared long-lasting nanoparticles is Zn y Ga2Cr x O4; among them, 1×10 -4 ≤x≤2×10 -3 , 0.6≤y≤1.

4.

8. Use of the ultra-small, high-performance near-infrared long afterglow nanoparticles according to any one of claims 6 to 7 in optical imaging of living organisms, molecular labeling or in the preparation of medical diagnostic reagents.

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