A near-infrared long-afterglow luminescent nano probe, a preparation method and application thereof

Abstract

The application discloses a kind of near-infrared long afterglow luminescent nano probes, its preparation method and application, belong to near-infrared long afterglow material field. With mesoporous silica as template, with zinc acetate, gallium nitrate, tin chloride, chromium acetate, chromium nitrate and yttrium nitrate as doped metal raw materials, long afterglow luminescent core is obtained by reaction and calcination;The outer layer of long afterglow luminescent core is coated with manganese dioxide, to obtain pre-product;Pre-product is surface modified, and coupling target molecule plerixafor, i.e. near-infrared long afterglow luminescent nano probe. The near-infrared long afterglow luminescent nano probe has good biological safety, can be effectively enriched in the tumor area in vivo after mouse tail vein injection, can realize high-sensitivity imaging of multiple small tumors in vivo under red light LED irradiation, and the imaging time is short, suitable for intraoperative imaging, can be used for the imaging of breast cancer tumor model to guide tumor resection.

Description

Technical Field

[0001] This invention belongs to the field of near-infrared long afterglow materials, and in particular to a near-infrared long afterglow luminescent nanoprobe, its preparation method and application. Background Technology

[0002] Cancer, lacking effective treatments, poses a serious threat to human health. Currently, surgical resection remains the preferred treatment for solid tumors. However, postoperative tumor recurrence and worsening often lead to treatment failure. Completely removing the tumor while preserving surrounding healthy tissue is a significant surgical challenge. During surgery, surgeons rely on vision, touch, and experience to distinguish tumor margins from healthy tissue, which can result in residual tumor or excessive removal of normal tissue. The lack of real-time intraoperative navigation further limits the precision of tumor resection, leading to a high probability of residual tumor.

[0003] Compared to traditional medical imaging (such as MRI, CT, or X-ray), near-infrared fluorescence imaging offers advantages such as real-time performance, high sensitivity, high resolution, and no radiation. Near-infrared fluorescent nanoprobes possess advantages such as good photostability, tunable spectrum, and simple surface modification, making them excellent tracers for tumor resection and providing navigation for accurate surgical removal. During surgical resection, the remaining tumor shrinks, placing higher demands on the sensitivity of imaging nanoprobes. Simultaneously, during the excitation of these nanoprobes, the organism emits its own fluorescence, resulting in a strong background signal and a low tumor-to-normal tissue (T / NT) signal ratio, limiting the identification of residual tumor. Near-infrared persistent luminescent nanoparticles are a novel type of bioimaging nanoprobe that stores energy during excitation and continues to emit afterglow after excitation. Using near-infrared long-afterglow luminescent nanoprobes for bioimaging completely avoids the interference of autofluorescence caused by excitation irradiation, significantly improving imaging sensitivity. Summary of the Invention

[0004] To overcome the above-mentioned technical defects, the present invention provides a near-infrared long-afterglow luminescent nanoprobe, its preparation method and application, so as to solve the problems involved in the background technology.

[0005] This invention provides a near-infrared long-afterglow luminescent nanoprobe, its preparation method, and its applications, including:

[0006] (1) Zinc acetate, gallium nitrate, tin chloride, chromium acetate, chromium nitrate and yttrium nitrate are mixed and added to deionized water and stirred to dissolve, thus obtaining a mixed metal solution;

[0007] (2) Add mesoporous silica powder to the above mixed metal solution and heat it to dry under vacuum to obtain mesoporous silica powder doped with doped metal raw materials.

[0008] (3) The mesoporous silica powder doped with doped metal raw materials is calcined at high temperature to obtain a long afterglow luminescent core;

[0009] (4) Coating the outer layer of the long afterglow luminescent core with manganese dioxide to obtain a pre-product;

[0010] (5) Perform surface modification on the pre-product to obtain a surface-modified pre-product;

[0011] (6) The target molecule pleroxafer is coupled to the surface of the modified preproduct to obtain the near-infrared long afterglow luminescent nanoprobe.

[0012] Preferably or optionally, the molar ratio of zinc, gallium, tin, oxygen, chromium and yttrium in the mixed metal solution is 1.2-1.4:1.3-1.5:0.2-0.4:3.5-4.5:0.004-0.006:0.0025-0.0035.

[0013] Preferably or optionally, the ratio of the mixed metal solution to mesoporous silica powder is 0.25-0.75 mL: 90-110 mg; the evaporation temperature is 50-80 °C, and the reaction time is 10-18 h.

[0014] Preferably or optionally, the method for producing mesoporous silica powder doped with a doped metal raw material includes the following steps:

[0015] Mesoporous silica powder doped with metal raw materials is calcined at 850-1000℃ for 2-5 hours to obtain a long afterglow luminescent core.

[0016] Preferably or optionally, the method of coating the outer layer of the long-afterglow luminescent core with manganese dioxide includes the following steps:

[0017] The obtained long afterglow luminescent cores were dispersed in deionized water. Then, potassium permanganate aqueous solution was added to the mixture under stirring. After mixing for 5-15 minutes, a certain amount of formamide was added, and the mixture was allowed to react under ultrasound for 10-40 minutes. The product was collected by centrifugation and washed with water to obtain the pre-product.

[0018] Preferably or optionally, the method for surface modification of the pre-product includes the following steps:

[0019] The obtained pre-product was added to an aqueous solution of poly(acrylamine hydrochloride), ultrasonically reacted for 1-3 hours, and washed with deionized water 2-4 times.

[0020] The sample was then dispersed in polyacrylic acid under ultrasonic treatment. After reacting for 1-3 hours, the product was collected by centrifugation and washed with water to obtain the surface-modified pre-product.

[0021] Preferably or optionally, the method for coupling the targeted molecule pleroxafer to the surface of the modified preproduct includes the following steps:

[0022] The obtained surface-modified preproduct was dispersed in MES buffer, and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide were added sequentially with stirring. After reacting for 0.5-3 h,

[0023] Adjust the pH of the mixture to 7-8, add plexafor dissolved in ethanol, and after 10-15 h of amidation reaction, wash the product with water and collect the near-infrared long afterglow luminescent nanoprobe by centrifugation.

[0024] The present invention also provides a near-infrared long-afterglow luminescent nanoprobe obtained by the preparation method of the aforementioned near-infrared long-afterglow luminescent nanoprobe.

[0025] The present invention also provides an application of the aforementioned near-infrared long-afterglow luminescent nanoprobe as a biomedical imaging material or in the preparation of such a material.

[0026] This invention relates to a near-infrared long-afterglow luminescent nanoprobe, its preparation method, and its applications. Compared with existing technologies, it has the following advantages: This invention uses mesoporous silica as a template to prepare a near-infrared long-afterglow luminescent nanoprobe, which exhibits a complete monodisperse mesoporous spherical structure. The near-infrared long-afterglow luminescent nanoprobe prepared by this invention, after intravenous injection into the tail vein of mice, can effectively accumulate in tumor regions in vivo. Under red LED irradiation, it not only achieves highly sensitive imaging of multiple small tumors in vivo, but also features short imaging time and high biocompatibility, making it suitable for intraoperative imaging and offering hope for complete tumor resection. Attached Figure Description

[0027] Figure 1 This is a transmission electron microscope (TEM) image (scale bar is 100 nm) of the near-infrared long-afterglow luminescent nanoprobe prepared in Example 1 of the present invention.

[0028] Figure 2 The image shows the TEM-elemental mapping (scale bar is 100 nm) of the near-infrared long-afterglow luminescent nanoprobe prepared in Example 1 of this invention.

[0029] Figure 3 The XRD pattern is shown in Example 1 of this invention.

[0030] Figure 4 The image shows the afterglow spectrum of the near-infrared long afterglow luminescent nanoprobe prepared in Example 1 of this invention.

[0031] Figure 5The image shows the afterglow decay curve of the near-infrared long afterglow luminescent nanoprobe prepared in Example 1 of this invention.

[0032] Figure 6 This is an image showing the afterglow decay of the long-afterglow core of the near-infrared long-afterglow luminescent nanoprobe prepared in Example 1 of the present invention.

[0033] Figure 7 The image shows the afterglow decay of the near-infrared long-afterglow luminescent nanoprobe prepared in Example 1 of this invention in solutions containing or without glutathione.

[0034] Figure 8 Confocal laser scanning microscope images of 4T1 cells incubated with the pre-product prepared in Example 1 of this invention and near-infrared long-afterglow luminescent nanoprobes for 2, 4, 6, and 8 hours, respectively.

[0035] Figure 9 Flow cytometry analysis was performed on the fluorescence intensity changes of 4T1 cells after incubation for 2, 4, 6, and 8 hours with the pre-product prepared in Example 1 of this invention and the near-infrared long-afterglow luminescent nanoprobe.

[0036] Figure 10 Cell viability of MCF-10A and NIH-3T3 cells after 24 h of treatment with the prepared near-infrared long-afterglow luminescent nanoprobe.

[0037] Figure 11 This is an example of afterglow imaging during the resection procedure.

[0038] Figure 12 This is an example of ex vivo afterglow imaging of microtumors removed in an application case.

[0039] Figure 13 This is an example of afterglow imaging of residual tumor tissue and muscle in an application case.

[0040] Figure 14 for Figure 12 The T / NT signal ratio analyzed in the analysis.

[0041] Figure 15 The images show bioluminescence before and after resection in an application example.

[0042] Figure 16 The images show H&E staining of microtumors, tumor remnants, and muscle in the application example. T1-T6 represent 6 microtumors, and R represents T4 remnants.

[0043] Figure 17 The Kaplan-Meier survival curves are for 10 mice with tumor resection or non-resection in the application example. Detailed Implementation

[0044] In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the invention. However, it will be apparent to those skilled in the art that the invention can be practiced without one or more of these details. In other instances, certain technical features well-known in the art have not been described in order to avoid obscuring the invention. Invention Overview

[0046] This invention provides a method for preparing near-infrared long-afterglow luminescent nanoprobes, comprising the following steps:

[0047] (1) Zinc acetate, gallium nitrate, tin chloride, chromium acetate, chromium nitrate and yttrium nitrate are mixed and added to deionized water and stirred to dissolve, to obtain a mixed metal solution; the molar ratio of zinc, gallium, tin, oxygen, chromium and yttrium in the mixed metal solution is 1.2-1.4∶1.3-1.5∶0.2-0.4∶3.5-4.5∶0.004-0.006∶0.0025-0.0035.

[0048] (2) Add mesoporous silica powder to the above mixed metal solution and heat it to dryness under vacuum conditions; the ratio of mixed metal solution to mesoporous silica powder is 0.25-0.75mL: 90-110mg; the evaporation temperature is 50-80℃ and the reaction time is 10-18h.

[0049] (3) The mesoporous silica powder doped with doped metal raw materials is calcined at high temperature to obtain a long afterglow luminescent core; wherein the calcination temperature is 700-950℃ and the time is 2-5h.

[0050] (4) Disperse 10-20 mg of long afterglow luminescent core in 30-50 mL of deionized water, then add 8-15 mL of potassium permanganate aqueous solution with a concentration of 5 mg / mL under stirring. After 5-15 min, add 1-1.5 mL of formamide and let the mixture react under ultrasound for 10-40 min. Centrifuge to collect the product and wash with water to obtain the pre-product.

[0051] (5) Add 10-30 mg of the obtained pre-product to 30-60 mL of 10 mg / mL poly(acrylamine hydrochloride) aqueous solution, sonicate for 1-3 h, wash with deionized water, then disperse the sample in 40-60 mL of 10 mg / mL polyacrylic acid under sonication, react for 1-4 h, centrifuge to collect the product, and wash with water to obtain the surface-modified pre-product.

[0052] (6) Disperse 5-20 mg of the surface-modified preproduct in 5-15 mL of MES buffer, add 2 mg of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 4 mg of N-hydroxysuccinimide in sequence under stirring, react for 0.5-3 h, adjust the pH of the mixture to 7-8, add 1 mg of plexafor dissolved in ethanol, after 10-15 h of amidation reaction, wash the product with water, and collect the near-infrared long afterglow luminescent nanoprobe by centrifugation.

[0053] The near-infrared long-afterglow luminescent nanoprobes were found to have a particle size of 80-200 nm. The manganese dioxide shell on these nanoprobes quenches the near-infrared long-afterglow luminescent nanoprobe signal in normal tissue, but degrades it in the tumor microenvironment due to excessive hydrogen peroxide and glutathione, leading to its recovery. This results in a significantly higher near-infrared long-afterglow luminescent nanoprobe signal at the tumor site compared to normal tissue, with a T / NT signal ratio reaching 15-30 in multiple small tumor models. The imaging time for these nanoprobes is only 1-2 minutes, and they exhibit good biocompatibility. Therefore, these near-infrared long-afterglow luminescent nanoprobes can be used for image-guided tumor resection in various tumor models.

[0054] The present invention will be further described below with reference to the embodiments. The examples described are intended to explain the present invention and should not be construed as limiting the present invention.

[0055] Example 1

[0056] (1) Zinc acetate, gallium nitrate, tin chloride, chromium acetate, chromium nitrate and yttrium nitrate are mixed and added to water and stirred to dissolve, thus obtaining a mixed metal solution; the concentration ratio of zinc, gallium, tin, oxygen, chromium and yttrium in the mixed metal solution is 1.3:1.4:0.3:4:0.005:0.003;

[0057] (2) Add 100 mg of mesoporous silica powder to the above 0.5 mL mixed metal solution, heat to 60 °C under vacuum, and react for 12 h;

[0058] (3) The material obtained in step (2) is calcined at 900℃ for 3 hours to obtain a long afterglow luminescent core;

[0059] (4) Disperse 15 mg of the long afterglow luminescent core obtained in step (3) in 40 mL of deionized water, then add 10 mL of potassium permanganate aqueous solution with a concentration of 5 mg / mL under stirring. After stirring for 10 min, add 1.2 mL of formamide and let the mixture react under ultrasound for 30 min. Centrifuge to collect the product and wash with water to obtain the pre-product.

[0060] (5) Add 20 mg of the preproduct obtained in step (4) to 50 mL of a 10 mg / mL aqueous solution of poly(acrylamine hydrochloride), sonicate for 2 h, and wash three times with deionized water. Then, disperse the sample in 50 mL of 10 mg / mL polyacrylic acid under sonication, react for 2 h, centrifuge to collect the product, and wash with water to obtain the surface-modified preproduct.

[0061] (6) Disperse 10 mg of the surface-modified pre-product obtained in step (5) in 10 mL of MES buffer, add 2 mg of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 4 mg of N-hydroxysuccinimide in sequence under stirring, after reacting for 1 h, adjust the pH of the mixture to 7.2, add 1 mg of the targeting molecule plexafor dissolved in ethanol, after amidation reaction for 12 h, wash the product with water, and collect by centrifugation to obtain near-infrared long afterglow luminescent nanoprobes.

[0062] Example 2

[0063] (1) Zinc acetate, gallium nitrate, tin chloride, chromium acetate, chromium nitrate and yttrium nitrate are mixed and added to water and stirred to dissolve, thus obtaining a mixed metal solution; the concentration ratio of zinc, gallium, tin, oxygen, chromium and yttrium in the mixed metal solution is 1.2:1.3:0.2:3.5:0.004:0.0025;

[0064] (2) Add 90 mg of mesoporous silica powder to the above 0.25 mL mixed metal solution, heat to 50 °C under vacuum, and react for 18 h;

[0065] (3) The material obtained in step (2) is calcined at 700℃ for 4 hours to obtain a long afterglow luminescent core;

[0066] (4) Disperse 10 mg of the long afterglow luminescent core obtained in step (3) in 30 mL of deionized water, then add 8 mL of potassium permanganate aqueous solution with a concentration of 5 mg / mL under stirring. After stirring for 5 min, add 1.0 mL of formamide and let the mixture react under ultrasound for 10 min. Centrifuge to collect the product and wash it with water to obtain the pre-product.

[0067] (5) Add 10 mg of the preproduct obtained in step (4) to 30 mL of a 10 mg / mL aqueous solution of poly(acrylamine hydrochloride), sonicate for 1 h, and wash three times with deionized water. Then, disperse the sample in 40 mL of 10 mg / mL polyacrylic acid under sonication, react for 1 h, centrifuge to collect the product, and wash with water to obtain the surface-modified preproduct.

[0068] (6) Disperse 5 mg of the surface-modified pre-product obtained in step (5) in 5 mL of MES buffer, add 2 mg of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 4 mg of N-hydroxysuccinimide in sequence under stirring, after reacting for 1 h, adjust the pH of the mixture to 7.2, add 1 mg of the targeting molecule pleroxafer dissolved in ethanol, after amidation reaction for 10 h, wash the product with water, and collect by centrifugation to obtain near-infrared long afterglow luminescent nanoprobes.

[0069] Example 3

[0070] (1) Zinc acetate, gallium nitrate, tin chloride, chromium acetate, chromium nitrate and yttrium nitrate are mixed and added to water and stirred to dissolve, thus obtaining a mixed metal solution; the concentration ratio of zinc, gallium, tin, oxygen, chromium and yttrium in the mixed metal solution is 1.4:1.5:0.4:4.5:0.006:0.0035;

[0071] (2) Add 110 mg of mesoporous silica powder to the above 0.75 mL mixed metal solution, heat to 80 °C under vacuum, and react for 10 h;

[0072] (3) The material obtained in step (2) is calcined at 950°C for 2 hours to obtain a long afterglow luminescent core;

[0073] (4) Disperse 20 mg of the long afterglow luminescent core obtained in step (3) in 50 mL of deionized water, then add 15 mL of potassium permanganate aqueous solution with a concentration of 5 mg / mL under stirring. After stirring for 15 min, add 1.5 mL of formamide and let the mixture react under ultrasound for 40 min. Centrifuge to collect the product and wash with water to obtain the pre-product.

[0074] (5) Add 30 mg of the preproduct obtained in step (4) to 60 mL of a 10 mg / mL aqueous solution of poly(acrylamine hydrochloride), sonicate for 3 h, and wash three times with deionized water. Then, disperse the sample in 60 mL of 10 mg / mL polyacrylic acid under sonication, react for 4 h, centrifuge to collect the product, and wash with water to obtain the surface-modified preproduct.

[0075] (6) Disperse 20 mg of the surface-modified pre-product obtained in step (5) in 15 mL of MES buffer, add 2 mg of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and 4 mg of N-hydroxysuccinimide in sequence under stirring, react for 3 h, adjust the pH of the mixture to 7.2, add 1 mg of the targeting molecule pleroxafer dissolved in ethanol, after 15 h of amidation reaction, wash the product with water, and collect by centrifugation to obtain the near-infrared long afterglow luminescent nanoprobe.

[0076] Testing and Discussion

[0077] The near-infrared long-afterglow luminescent nanoprobe prepared in Example 1 was characterized by its morphology using transmission electron microscopy, with a scale bar of 100 nm. For example... Figure 1 As shown, it exhibits a regular and monodisperse spherical structure with a diameter of approximately 130 nm. Figure 2 The image shows the TEM-elemental mapping of the near-infrared long-afterglow luminescent nanoprobe prepared in Example 1, with a scale bar of 100 nm, proving that it was successfully doped with the corresponding metal element. Figure 3 The XRD pattern of the near-infrared long-afterglow luminescent nanoprobe prepared in Example 1 shows that the product is an amorphous zinc gallate structure encapsulated in manganese dioxide. Figure 4 The afterglow spectrum of the fabricated near-infrared long afterglow luminescent nanoprobe; Figure 5 The afterglow decay curve further proves the near-infrared afterglow emission characteristics of the product. The manganese dioxide shell on the near-infrared long afterglow emission nanoprobe can quench the near-infrared long afterglow emission nanoprobe signal, and the near-infrared long afterglow emission nanoprobe signal can be restored after the manganese dioxide shell degrades. Figure 6 An image showing the afterglow decay at the core of the long afterglow. Figure 7 Images of the afterglow decay of the long-afterglow nanoprobe in solutions with or without glutathione reveal enhanced afterglow luminescence of the nanoprobe under glutathione reduction conditions in the tumor microenvironment. Figure 8 Confocal laser scanning microscopy images of 4T1 cells incubated with the pre-product and near-infrared long-afterglow luminescent nanoprobes for 2, 4, 6, and 8 hours, respectively. Figure 9 Flow cytometry analysis of 4T1 cells incubated with the pre-product and near-infrared long-afterglow luminescent nanoprobe for 2, 4, 6, and 8 hours showed that the prepared near-infrared long-afterglow luminescent nanoprobe had specific targeting properties in vitro. Figure 10 The cell viability of MCF-10A and NIH-3T3 cells treated with the prepared near-infrared long-afterglow luminescent nanoprobe for 24 h indicates that the prepared near-infrared long-afterglow luminescent nanoprobe has good cell compatibility.

[0078] Application examples

[0079] Mice were intravenously injected with the near-infrared long-persistence luminescent nanoprobe prepared in Example 1, and long-persistence imaging was used to guide the surgical resection of multiple small breast cancers. Figure 11 For afterglow imaging during the resection procedure, Figure 12 For ex vivo afterglow imaging to remove microtumors, Figure 13 For afterglow imaging of residual tumor tissue and muscle, Figure 14 for Figure 12 The T / NT signal ratio analyzed in the middle, Figure 15 Images of bioluminescence before and after resection. Figure 16 H&E staining images of microtumors, tumor remnants, and muscle; T1-T6 represent 6 microtumors, and R represents T4 remnants. Figure 17 The Kaplan-Meier survival curves for 10 mice with or without tumor resection demonstrate that the survival rate of mice is significantly improved after tumor resection using this technique, while also proving the biosafety of the material.

[0080] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

Claims

1. A method for preparing a near-infrared long-afterglow luminescent nanoprobe, characterized in that, Includes the following steps: (1) Zinc acetate, gallium nitrate, tin chloride, chromium acetate, chromium nitrate and yttrium nitrate are mixed and added to deionized water and stirred to dissolve, thus obtaining a mixed metal solution; (2) Add mesoporous silica powder to the above mixed metal solution and heat it to dry under vacuum to obtain mesoporous silica powder doped with doped metal raw materials. (3) The mesoporous silica powder doped with doped metal raw materials is calcined at high temperature to obtain a long afterglow luminescent core; (4) Coating the outer layer of the long afterglow luminescent core with manganese dioxide to obtain a pre-product; (5) Add the obtained pre-product to an aqueous solution of poly(acrylamine hydrochloride), sonicate for 1-3 hours, and wash with deionized water 2-4 times; then disperse the sample in polyacrylic acid under sonication, react for 1-3 hours, centrifuge to collect the product, and wash with water to obtain the surface-modified pre-product. (6) The obtained surface-modified preproduct was dispersed in MES buffer, and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride and N-hydroxysuccinimide were added sequentially under stirring. After reacting for 0.5-3h, the pH of the mixture was adjusted to 7-8, and plexafor dissolved in ethanol was added. After amidation reaction for 10-15h, the product was washed with water and collected by centrifugation.

2. The method for preparing near-infrared long-afterglow luminescent nanoprobes according to claim 1, characterized in that, The molar ratio of zinc, gallium, tin, oxygen, chromium and yttrium in the mixed metal solution is 1.2-1.4:1.3-1.5:0.2-0.4:3.5-4.5:0.004-0.006:0.0025-0.0035.

3. The method for preparing near-infrared long-afterglow luminescent nanoprobes according to claim 1, characterized in that, The ratio of the mixed metal solution to the mesoporous silica powder is 0.25-0.75 mL: 90-110 mg; the evaporation temperature is 50-80℃, and the reaction time is 10-18 h.

4. The method for preparing near-infrared long-afterglow luminescent nanoprobes according to claim 1, characterized in that, The method for producing mesoporous silica powder doped with doped metal raw materials includes the following steps: Mesoporous silica powder doped with metal raw materials is calcined at 850-1000℃ for 2-5 hours to obtain a long afterglow luminescent core.

5. The method for preparing near-infrared long-afterglow luminescent nanoprobes according to claim 1, characterized in that, The method for coating the outer layer of a long-afterglow luminescent core with manganese dioxide includes the following steps: The obtained long-afterglow luminescent cores were dispersed in deionized water, and then potassium permanganate aqueous solution was added under stirring. After mixing for 5-15 minutes, a certain amount of formamide was added, and the mixture was allowed to react under ultrasound for 10-40 minutes. The product was collected by centrifugation and washed with water to obtain the pre-product.

6. A near-infrared long-afterglow luminescent nanoprobe obtained by the preparation method of the near-infrared long-afterglow luminescent nanoprobe according to any one of claims 1 to 5.

7. An application of the near-infrared long-afterglow luminescent nanoprobe according to claim 6 in the preparation of biomedical imaging materials.

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