A near-infrared two-region light excited rare earth fluorescence imaging probe and a preparation method and application thereof

Abstract

The application discloses a near-infrared two-region light excited rare earth fluorescence imaging probe and a preparation method and application thereof, and belongs to the technical field of near-infrared two-region fluorescence imaging. Compared with existing near-infrared one-region light excited fluorescence imaging reagents, the prepared rare earth fluorescence imaging probe is excited in the near-infrared two-region, has stronger tissue penetration advantages, and is more conducive to in-vivo fluorescence imaging. The application adopts a biological orthogonal mode to make the fluorescence probe partially enriched in tumors, can effectively reduce toxicity and enhance uptake, enhance the enrichment degree of the imaging probe in the tumors and prolong the enrichment time.

Description

Technical Field

[0001] This invention belongs to the field of near-infrared II fluorescence imaging technology, specifically relating to a near-infrared II photoexcited rare-earth fluorescence imaging probe, its preparation method, and its application. Background Technology

[0002] Fluorescence imaging, with its advantages of high sensitivity, high spatiotemporal resolution, and rapid feedback, has become a promising imaging technique for tumor diagnosis. Currently, visible light probes are widely used in in vitro studies, but their in vivo application is limited by the strong absorption and scattering of visible light by biological media. To circumvent these drawbacks, researchers have developed numerous near-infrared I (700–900 nm) fluorescent probes, but existing techniques are still affected by light penetration depth and light attenuation. Optical simulations predict that the near-infrared II (NIR-II, 1000–1700 nm) fluorescence imaging window can significantly reduce the autofluorescence of biological tissues and lower the light scattering coefficient. Rare-earth nanoparticles with NIR-II fluorescence emission are suitable for use as fluorescence imaging probes due to their designable narrow emission bands, high stability against photobleaching, and long fluorescence lifetime, showing significant application potential in tumor and vascular imaging. While traditional materials have emission peaks in the near-infrared II region, their excitation light (808 nm and 980 nm) is confined to the near-infrared I region, which is a major obstacle to high-resolution fluorescence imaging-guided surgery. Furthermore, since fluorescent imaging probes are less enriched within tumors, it is difficult to guide surgical resection using NIR-II fluorescence imaging. By employing a bioorthogonal approach, the active targeting capability of the material can be further enhanced, making it easier for the human eye to distinguish tumor tissue and further guide tumor resection.

[0003] The lanthanides are 15 elements in Group IIIB of Period 6 of the periodic table, ranging from lanthanum to lutetium, with the electron configuration [Xe]4f. n-1 5d 0-1 6s 2 (n = 1-15). Trivalent lanthanide ions (Ln) 3+ Rare earth elements (Ln) are the most common and stable oxidation states of the lanthanides, with their f orbitals being empty, half-occupied, or fully occupied, respectively. It is precisely because of the abundant 4f electrons in rare earth ions that they possess a rich spectrum of terms. Although intraconfigurational transitions are essentially impossible, the binding of intrinsic states leads to some permitted intraconfigurational transitions, thus endowing Ln with... 3+ The unique optical properties of lanthanides, including excellent photostability, large Stokes / anti-Stokes shift, narrow-band emission, and long fluorescence lifetime, make their use in fluorescence imaging a great advantage and have great potential.

[0004] Optical imaging strategies rely on the fluorescence, bioluminescence, and light absorption of fluorescent probes, tracers, and contrast agents. Optical imaging is safe and effective, but it often lacks penetration depth when using visible light. The effectiveness of optical imaging is determined by the interaction of light with tissue, including absorption and scattering, and is also affected by inherent tissue autofluorescence, which decreases with increasing wavelength. Increasing the wavelength into the near-infrared (NIR) region (700-1700 nm) significantly reduces the corresponding background interference and lowers the required injection dose, while also reducing false positives. Therefore, biocompatible near-infrared fluorescent imaging reagents have attracted widespread interest from researchers in recent years, especially those with fluorescence emission within the biological window spectral range (first biological window 650-950 nm; second biological window 1000-1700 nm). Rare-earth near-infrared luminescent nanomaterials, capable of generating near-infrared emission within the "second transparent biological window" with less scattering by biological tissue, have been developed for achieving highly sensitive in vivo fluorescence imaging.

[0005] The choice of the host lattice determines the distance between dopant ions, their relative spatial positions, coordination number, and the type of anion surrounding the dopant. Therefore, the properties of the host lattice and its interaction with the dopant ions have a significant impact on the optical properties of the material. Furthermore, the matrix material typically needs to have low phonon energy and a tight lattice match with the dopant ions. Since all trivalent rare earth ions exhibit similar ion sizes and chemical properties, their inorganic compounds are ideal matrix materials for lanthanide dopants. In recent years, fluorescent imaging probes have been extensively studied, but their excitation light is mostly at 808 nm and 980 nm, which severely limits NIR-II fluorescence imaging-guided surgical resection. By constructing a core-shell structure NaEr... (1-a-b-c) F4:Ho a ,Yb b ,Y c @NaY (1-d-e-f) F4:Yb d Er e ,Nd f It can achieve strong near-infrared II fluorescence emission at 1150 nm under 1530 nm laser excitation, which can be used for fluorescence imaging of tumors. On the other hand, the enrichment of fluorescent imaging reagents in tumors also affects the imaging effect. By introducing click chemistry in a bioorthogonal manner, the enrichment of materials can be greatly increased, thereby further improving the imaging effect. Summary of the Invention

[0006] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0007] This invention develops a novel near-infrared II rare-earth fluorescence imaging probe for surgical guidance and its preparation method. Using NaEr... (1-a-b-c) F4:Ho a ,Yb b ,Y c NaY is epitaxially grown on its surface as the core. (1-d-e-f) F4:Yb d Er e ,Nd f By designing its structure and energy transfer pathway, it can emit strong near-infrared II fluorescence emission of 1150nm under 1530nm laser excitation. By introducing a polyethylene glycol-based polymer containing dibenzyl ethylene oxide (DBCO) groups on its surface and treating the tumor with 1,3,4,6-tetra-O-acetyl-N-azidoacetylaminomannose (Ac4ManNAz), NIR-II fluorescence imaging and surgical resection of the tumor can be achieved.

[0008] In view of the problems existing in the above and / or prior art, the present invention is proposed.

[0009] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and provide a rare-earth fluorescence imaging probe excited by near-infrared II light.

[0010] To address the aforementioned technical problems, this invention provides the following technical solution: the probe is composed of rare-earth fluorescent imaging nanoparticles NaEr (1-a-b-c) F4:Ho a ,Yb b ,Y c @NaY (1-d-e-f) F4:Yb d Er e ,Nd f It consists of a hydrophilic shell;

[0011] The rare-earth fluorescent imaging nanoparticles have a core-shell structure, which includes a fluorescent core and a shell.

[0012] The fluorescent core is NaEr. (1-a-b-c) F4:Ho a ,Yb b ,Y c Where, 0≤a≤20%; 0≤b≤80%; 0≤c≤30%;

[0013] The shell is NaY (1-d-e-f) F4:Yb d Er e ,Nd f Where 0 ≤ d ≤ 60%; 0 ≤ e ≤ 15%; 0 ≤ f ≤ 40%.

[0014] As a preferred embodiment of the near-infrared II light-excited rare-earth fluorescence imaging probe of the present invention, the molar ratio of the fluorescent core to the shell is 1:(0.5-5).

[0015] As a preferred embodiment of the near-infrared II photoexcited rare-earth fluorescence imaging probe of the present invention, wherein: the hydrophilic shell is a PEG molecule, including DSPE-PEG. 1000 -DBCO, NH2-PEG 1000 -DBCO, COOH-PEG 1000 -DBCO,DSPE-PEG 2000 -DBCO or DSPE-PEG 3000 One or more of -DBCO.

[0016] As a preferred embodiment of the near-infrared II light-excited rare-earth fluorescent imaging probe of the present invention, wherein the mass ratio of the rare-earth fluorescent imaging nanoparticles to the hydrophilic shell is (2-3):5.

[0017] Another objective of this invention is to overcome the shortcomings of the prior art and provide a method for preparing a rare-earth fluorescence imaging probe excited by near-infrared II light.

[0018] To solve the above-mentioned technical problems, the present invention provides the following technical solutions, including:

[0019] One or more of Er source, Ho source, Y source, Yb source, oleic acid, oleylamine and octadecene are dissolved and then F source and Na source are added to react. After the reaction is completed, the mixture is washed to obtain the fluorescent core.

[0020] The fluorescent core is mixed with one or more of the following sources: Na source, Y source, F source, Yb source, Er source, Nd source, oleic acid, oleylamine and octadecene, dissolved and reacted. After the reaction is completed, the mixture is washed to obtain rare earth fluorescent imaging nanoparticles.

[0021] Rare earth fluorescent imaging probes were prepared by dissolving rare earth fluorescent imaging nanoparticles and hydrophilic shell material PEG molecules in a solvent and then sonicating them.

[0022] In a preferred embodiment of the method for preparing the near-infrared II region photoexcited rare-earth fluorescence imaging probe of the present invention, the Er source comprises one or more of ErCl3, Er(NO)3, Er(CH3COO)3, or Er(CF3COO)3; the Ho source comprises one or more of HoCl3, Ho(NO)3, Ho(CH3COO)3, or Ho(CF3COO)3; and the Y source comprises YCl3, Y(NO)3, Y(CH3COO)3, or Y(CF3COO)3. One or more of the following: the Yb source includes one or more of YbCl3, Yb(NO)3, Yb(CH3COO)3, or Yb(CF3COO)3; the F source includes one or more of NH4F and Ln(CF3COO)3 (Ln = Er, Ho, Y, Yb); the Na source includes one or more of NaOH, sodium oleate, and sodium trifluoroacetate; and the Nd source includes one or more of NdCl3, Nd(NO)3, Nd(CH3COO)3, or Nd(CF3COO)3.

[0023] As a preferred embodiment of the method for preparing the near-infrared II region photoexcited rare-earth fluorescence imaging probe of the present invention, wherein: the reaction, wherein the reaction temperature is 290-310℃ and the reaction time is 45-120min.

[0024] As a preferred embodiment of the method for preparing the near-infrared II region photoexcited rare-earth fluorescence imaging probe of the present invention, the cleaning solution includes one or more of anhydrous ethanol, acetone and cyclohexane solution; the solvent includes one or more of acetone, tetrahydrofuran, water and cyclohexane.

[0025] Another objective of this invention is to overcome the shortcomings of the prior art and provide an application of a near-infrared II region photoexcited rare-earth fluorescence imaging probe.

[0026] As a preferred embodiment of the application of the near-infrared II light-excited rare-earth fluorescence imaging probe of the present invention, wherein the probe is applied to the field of near-infrared II fluorescence imaging.

[0027] As a preferred embodiment of the application of the near-infrared II light-excited rare-earth fluorescence imaging probe of the present invention, wherein the rare-earth fluorescence imaging probe is enriched at the tumor site in a bioorthogonal manner to guide surgical resection.

[0028] Beneficial effects of this invention:

[0029] (1) Compared with existing imaging reagents excited by near-infrared I region light, the emission peak of the present invention is located at 1150nm, which is in the near-infrared II region. The fluorescence emission peak is far away from the water absorption peak, which can effectively avoid biological autofluorescence, scattering loss, etc., and has a stronger tissue penetration advantage. It is more conducive to in vivo fluorescence imaging and suitable for in vivo guided surgery.

[0030] (2) The present invention uses near-infrared II excitation light, which has a deeper tissue penetration depth and less energy attenuation than near-infrared I excitation light (such as the common 808nm and 980nm), making it more suitable for in vivo guided surgical resection of tumors.

[0031] (3) The present invention can enhance the enrichment degree of imaging probes in tumors and prolong the enrichment time through biological orthogonal reaction.

[0032] (4) The present invention uses a biological orthogonal method to enrich the fluorescent probe in the tumor part, which can effectively reduce toxicity and enhance uptake. Attached Figure Description

[0033] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0034] Figure 1 This is a flowchart illustrating the preparation process of the rare-earth fluorescent imaging probe of Example 1 of the present invention.

[0035] Figure 2 This is a TEM image of the fluorescent core obtained in Example 1 of the present invention.

[0036] Figure 3 This is a TEM image of the rare earth fluorescent imaging nanoparticles prepared in Example 1 of the present invention.

[0037] Figure 4 The near-infrared fluorescence emission spectrum of the rare earth fluorescent imaging probe prepared in Example 1 of this invention is shown.

[0038] Figure 5 Near-infrared 2D imaging (a) and digital image (b) of a mouse before tumor removal.

[0039] Figure 6 Near-infrared 2D imaging (a) and digital image (b) of the skin at the tumor site before tumor removal in mice.

[0040] Figure 7 This is a near-infrared 2D imaging image of the tumor tissue after removal.

[0041] Figure 8 The images show the near-infrared fluorescence emission spectra of the rare-earth fluorescent imaging probes prepared in Examples 1, 2, and 3.

[0042] Figure 9 The near-infrared fluorescence emission spectra of the rare earth fluorescent imaging probes prepared in Examples 1, 4, 5, and 6 are shown. Detailed Implementation

[0043] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0044] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0045] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0046] Unless otherwise specified, all raw materials used in this invention are commercially available.

[0047] Example 1

[0048] This embodiment provides a method for preparing a rare-earth fluorescent imaging probe, referring to... Figure 1 Specifically:

[0049] Step 1: Add 0.78 mmol ErCl3, 0.02 mmol HoCl3, and 0.2 mmol YbCl3 to a three-necked flask containing 7 mL oleic acid and 15 mL octadecene. Heat the mixture to 165 °C under argon protection until a clear solution is formed. After cooling, add 14 mL of methanol solution containing 4 mmol NH4F and 2.5 mmol NaOH. Then raise the temperature to 300 °C and hold for 60 min. After cooling to room temperature, add excess ethanol to the mixture and centrifuge at 10000 rpm for 10 min. Remove the supernatant and wash three times with a cyclohexane and ethanol mixture to obtain the fluorescent core NaErF4:Ho. 0.02 ,Yb 0.2 .

[0050] Step 2: Add 1 mmol of yttrium trifluoroacetate, 1 mmol of sodium trifluoroacetate, and the product from Step 1 to a three-necked flask containing 6 mL of oleic acid and 15 mL of octadecene. Heat the mixture to 150°C under argon protection until a clear solution forms. Then, raise the temperature to 300°C and maintain this temperature for 60 min. After cooling to room temperature, add excess ethanol to the mixture. Centrifuge at 10,000 rpm for 10 min. Remove the supernatant and wash twice with a mixture of cyclohexane and ethanol to obtain rare-earth fluorescent imaging nanoparticles NaErF4:Ho. 0.02 ,Yb 0.2 @NaYF4.

[0051] Step 3: The cyclohexane solution of rare earth fluorescent imaging nanoparticles is ultrasonically mixed with 20 mg / mL of DSPE-PEG-DBCO aqueous solution (i.e., the mass ratio of rare earth fluorescent imaging nanoparticles to DSPE-PEG-DBCO is 1:2) for 10 min to obtain the final product, the rare earth fluorescent imaging probe.

[0052] The application of rare-earth fluorescent imaging probes to guide surgical resection is as follows: female nude mice were acclimatized to the environment for 2 days, and 4T1 tumor cells were injected into their backs. After 9 days of growth, Ac4ManNAz was injected into the tumor once a day for three consecutive days to create an artificial receptor. 100 μL of the final product, rare-earth fluorescent imaging probe (10 mg / mL), was injected into the tail vein. Fluorescence imaging was performed 24 hours later, and the surgery was performed using fluorescence imaging.

[0053] Figure 2 The image shows a TEM image of the fluorescent core obtained in Example 1 of this invention. As can be seen from the image, a rare earth luminescent core with good crystallinity and monodispersity was successfully synthesized, indicating that it can be further coated with an inert shell for the next experiment.

[0054] Figure 3 The image shown is a TEM image of the rare earth fluorescent imaging nanoparticles prepared in Example 1 of this invention. It can be seen that a monodisperse rare earth luminescent core-shell structure was successfully synthesized, indicating that the next step of water conversion can be carried out and that the uniform and dispersed structure can ensure its use in vivo.

[0055] Figure 4 The near-infrared fluorescence emission spectrum of the rare-earth fluorescent imaging probe prepared in Example 1 of this invention shows that the probe emits fluorescence peaks of 980nm and 1150nm under 1530nm excitation. The 1150nm peak can be used as near-infrared II imaging-guided surgical resection, indicating that a nanoplatform for near-infrared II excitation and near-infrared II emission has been successfully prepared.

[0056] Figure 5Near-infrared II imaging (a) and digital image (b) of mice before tumor removal show strong near-infrared II fluorescence emission at the tumor site, illuminating the tumor and indicating that the material was sufficiently enriched at the tumor site.

[0057] Figure 6 Near-infrared 2D imaging (a) and digital image (b) of the skin at the tumor site before tumor removal in mice show that the entire tumor is illuminated after the skin is cut, indicating that tumor removal can be guided by imaging.

[0058] Figure 7 The near-infrared 2D imaging of the removed tumor tissue shows that the outline of the removed tumor is clear, indicating that this method can effectively guide the surgical removal of the tumor.

[0059] Example 2

[0060] The difference between this embodiment and Example 1 is that the raw materials 0.78 mmol ErCl3, 0.02 mmol HoCl3, and 0.2 mmol YbCl3 are adjusted to 0.79 mmol ErCl3, 0.01 mmol HoCl3, and 0.2 mmol YbCl3. The remaining preparation process is the same as in Example 1, yielding rare-earth fluorescent imaging nanoparticles NaEr 0.79 F4:Ho 0.01 ,Yb 0.2 A rare-earth fluorescent imaging probe was prepared using @NaYF4.

[0061] Example 3

[0062] The difference between this embodiment and Example 1 is that the raw materials 0.78 mmol ErCl3, 0.02 mmol HoCl3, and 0.2 mmol YbCl3 were adjusted to 0.77 mmol ErCl3, 0.03 mmol HoCl3, and 0.2 mmol YbCl3. The remaining preparation process is the same as in Example 1, yielding rare-earth fluorescent imaging nanoparticles NaEr... 0.77 F4:Ho 0.03 ,Yb 0.2 A rare-earth fluorescent imaging probe was prepared using @NaYF4.

[0063] Figure 8 The near-infrared fluorescence emission spectrum of the rare earth fluorescent imaging probes prepared in the above embodiments shows that the fluorescence emission intensity of Example 1 is significantly stronger than that of the rare earth fluorescent imaging probes prepared in Examples 2 and 3. The rare earth fluorescent imaging probe prepared in Example 1 has the best emission intensity.

[0064] Example 4

[0065] The difference between this embodiment and Example 1 is that the amounts of 0.78 mmol ErCl3, 0.02 mmol HoCl3, and 0.2 mmol YbCl3 were adjusted to 0.98 mmol ErCl3 and 0.02 mmol HoCl3. The remaining preparation processes were the same as in Example 1, yielding rare-earth fluorescent imaging nanoparticles NaEr... 0.98 F4:Ho 0.02 A rare-earth fluorescent imaging probe was prepared using @NaYF4.

[0066] Example 5

[0067] The difference between this embodiment and Example 1 is that the amounts of 0.78 mmol ErCl3, 0.02 mmol HoCl3, and 0.2 mmol YbCl3 were adjusted to 0.99 mmol ErCl3 and 0.01 mmol HoCl3, respectively. The remaining preparation processes were the same as in Example 1, yielding rare-earth fluorescent imaging nanoparticles NaEr... 0.99 F4:Ho 0.01 A rare-earth fluorescent imaging probe was prepared using @NaYF4.

[0068] Example 6

[0069] The difference between this embodiment and Example 1 is that the amounts of 0.78 mmol ErCl3, 0.02 mmol HoCl3, and 0.2 mmol YbCl3 were adjusted to 0.97 mmol ErCl3 and 0.03 mmol HoCl3, respectively. All other preparation processes remained the same as in Example 1, yielding rare-earth fluorescent imaging nanoparticles NaEr... 0.97 F4:Ho 0.03 A rare-earth fluorescent imaging probe was prepared using @NaYF4.

[0070] Figure 9 The near-infrared fluorescence emission spectrum of the rare earth fluorescent imaging probes prepared in the above embodiments shows that the fluorescence emission intensity of Example 1 is significantly stronger than that of the rare earth fluorescent imaging probes prepared in Examples 4 to 6. The rare earth fluorescent imaging probe prepared in Example 1 has the best emission intensity.

[0071] Example 7

[0072] The difference between this embodiment and Example 1 is that the mass ratio of rare earth fluorescent imaging nanoparticles to DSPE-PEG-DBCO is adjusted from 1:2 to 2:5. The rest of the preparation process is the same as in Example 1, and a rare earth fluorescent imaging probe is obtained.

[0073] Example 8

[0074] The difference between this embodiment and Example 1 is that the mass ratio of rare earth fluorescent imaging nanoparticles to DSPE-PEG-DBCO is adjusted from 1:2 to 3:5. The rest of the preparation process is the same as in Example 1, and a rare earth fluorescent imaging probe is obtained.

[0075] Example 9

[0076] The difference between this embodiment and Example 8 is that the hydrophilic shell DSPE-PEG-DBCO is changed to DSPE-PEG-NH2, while the rest of the preparation process is the same as in Example 8, to obtain a rare earth fluorescent imaging probe.

[0077] In vivo imaging tests were performed on the probes prepared in the above embodiments. Compared with Embodiment 1, the results showed that the imaging effect was not as good as that of Embodiment 1, and the illumination effect was poor. It was impossible to perform tumor-guided surgery with complete and bright illumination as in Embodiment 1.

[0078] Example 10

[0079] The difference between this embodiment and Example 1 is that the reaction temperature was adjusted from 300℃ to 290℃. All other preparation processes are the same as in Example 1, resulting in a rare-earth fluorescent imaging probe.

[0080] Example 11

[0081] The difference between this embodiment and Example 1 is that the reaction temperature was adjusted from 300℃ to 310℃. All other preparation processes are the same as in Example 1, resulting in a rare-earth fluorescent imaging probe.

[0082] In vivo imaging tests were performed on the probes prepared in the above embodiments. Compared with Embodiment 1, the results showed that the imaging effect was not as good as that of Embodiment 1, and the illumination effect was poor. It was impossible to perform tumor-guided surgery with complete and bright illumination as in Embodiment 1.

[0083] Comparative Example 1

[0084] This comparative example provides a conventional method for preparing rare-earth fluorescent imaging probes. Specifically, holmium trifluoroacetate, erbium trifluoroacetate, and ytterbium trifluoroacetate are added to a 100 mL three-necked flask in a specific ratio, along with 6 mL of oleic acid and 15 mL of octadecene. The mixture is heated to 300 °C and maintained for 60 min. After cooling, the sample is washed twice with cyclohexane and ethanol. Alternatively, the above product is mixed with yttrium trifluoroacetate in a specific ratio and added to a 100 mL three-necked flask, along with 6 mL of oleic acid and 15 mL of octadecene. The mixture is heated to 300 °C and maintained for 60 min. After cooling, the sample is washed twice with cyclohexane and ethanol.

[0085] Compared with Example 1, the probe of Example 1 had poor quality control and no target emission peak was found.

[0086] Compared to existing near-infrared I-region photoexcitation imaging reagents, the rare-earth fluorescent imaging probes prepared in this invention are excited in the near-infrared II region, exhibiting stronger tissue penetration advantages and being more conducive to in vivo fluorescence imaging. This invention employs a bioorthogonal approach to enrich the fluorescent probes in tumor regions, effectively reducing toxicity and enhancing uptake, thereby increasing the enrichment degree of the imaging probes within the tumor and prolonging the enrichment time.

[0087] This invention uses near-infrared II excitation light, which has a deeper tissue penetration depth and less energy attenuation than near-infrared I excitation light (such as the common 808nm and 980nm), making it more suitable for in vivo guided surgical resection of tumors.

[0088] The emission peak of this invention is located at 1150nm, in the near-infrared II region, and far from the water absorption peak. This can effectively avoid biological autofluorescence, scattering loss, etc., making it more suitable for in vivo guided surgery.

[0089] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A rare-earth fluorescence imaging probe excited by near-infrared II light, characterized in that: The probe is composed of rare-earth fluorescent imaging nanoparticles NaEr. 0.78 F4:Ho 0.02 ,Yb 0.2 It consists of @NaYF4 and a hydrophilic shell; The rare-earth fluorescent imaging nanoparticles have a core-shell structure, comprising a fluorescent core and a shell, wherein the fluorescent core is NaEr. 0.78 F4:Ho 0.02 ,Yb 0.2 ; The hydrophilic shell is a PEG molecule, selected from DSPE-PEG. 1000 -DBCO, NH2-PEG 1000 -DBCO, COOH-PEG 1000 -DBCO,DSPE-PEG 2000 -DBCO or DSPE-PEG 3000 One or more of -DBCO, with a mass ratio of rare earth fluorescent imaging nanoparticles to a hydrophilic shell of (2~3):

5.

2. The near-infrared II light-excited rare-earth fluorescence imaging probe as described in claim 1, characterized in that: The molar ratio of the fluorescent core to the shell is 1:(0.5~5).

3. The method for preparing a rare-earth fluorescence imaging probe excited by near-infrared II light as described in claim 1, characterized in that: include, After mixing Er source, Ho source, Y source, Yb source, oleic acid, oleylamine and octadecene, F source and Na source were added to react. After the reaction was completed, the mixture was washed to obtain the fluorescent core. The fluorescent core was mixed with Na source, Y source, F source, oleic acid, oleylamine and octadecene and reacted. After the reaction was completed, the mixture was washed to obtain rare earth fluorescent imaging nanoparticles. Rare earth fluorescent imaging probes were prepared by dissolving rare earth fluorescent imaging nanoparticles and hydrophilic shell material PEG molecules in a solvent and then sonicating them. The solvent is selected from one or more of water or cyclohexane.

4. The method for preparing a rare-earth fluorescence imaging probe excited by near-infrared II light as described in claim 3, characterized in that: The Er source includes one or more of ErCl3, Er(NO3)3, Er(CH3COO)3, or Er(CF3COO)3; the Ho source includes one or more of HoCl3, Ho(NO3)3, Ho(CH3COO)3, or Ho(CF3COO)3; the Y source includes one or more of YCl3, Y(NO3)3, Y(CH3COO)3, or Y(CF3COO)3; the Yb source includes one or more of YbCl3, Yb(NO3)3, Yb(CH3COO)3, or Yb(CF3COO)3; the F source includes one or more of NH4F and Ln(CF3COO)3, wherein Ln = Er, Ho, Y, Yb; and the Na source includes one or more of NaOH, sodium oleate, and sodium trifluoroacetate.

5. The method for preparing a rare-earth fluorescence imaging probe excited by near-infrared II light as described in claim 3, characterized in that: The reaction is carried out at a temperature of 290-310°C for 45-120 minutes.

6. The method for preparing a rare-earth fluorescence imaging probe excited by near-infrared II light as described in claim 3, characterized in that: The cleaning solution includes one or more of anhydrous ethanol, acetone, and cyclohexane solution.

7. The application of the near-infrared II light-excited rare-earth fluorescence imaging probe as described in claim 1 or 2, characterized in that: The probe is used in near-infrared II fluorescence imaging.

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