CN113927027A

CN113927027A - Near-infrared region-excited rare earth nanocrystal loaded with viroid hollow manganese oxide and preparation method and application thereof

Info

Publication number: CN113927027A
Application number: CN202111096606.6A
Authority: CN
Inventors: 刘小龙; 王培园; 吴名; 李佳琦; 李阳; 蔺金燕; 罗强
Original assignee: Mengchao Hepatobiliary Hospital Of Fujian Medical University (fuzhou Hospital For Infectious Diseases)
Current assignee: Mengchao Hepatobiliary Hospital Of Fujian Medical University (fuzhou Hospital For Infectious Diseases)
Priority date: 2021-09-16
Filing date: 2021-09-16
Publication date: 2022-01-14
Anticipated expiration: 2041-09-16
Also published as: CN113927027B; WO2023041005A1

Abstract

The invention discloses a rare earth nanocrystalline excited by near-infrared dib region loaded by viroid hollow oxide, and a preparation method and application thereof₄:2％Ho@NaYF₄And (3) modifying the rare earth nano material on the surface of the viroid hollow manganese oxide perfused on the IR1064 through an amide reaction to obtain the fluorescent composite probe with good biocompatibility and tumor microenvironment response. After the manganese oxide of the fluorescent composite probe is degraded at the tumor, manganese ions are used for chemokinetic treatment of a metastasis and a nuclear magnetic resonance imaging contrast agent, and the released rare earth nanocrystal has 1530nm excitation and 650nm excitationAnd 1180nm of emitted light, wherein 1180nm can be used for tumor imaging navigation surgical resection without background interference and with strong resolution and tissue penetration in a near infrared region II, and 650nm can be used for near infrared region I fluorescence imaging.

Description

Near-infrared region-excited rare earth nanocrystal loaded with viroid hollow manganese oxide and preparation method and application thereof

Technical Field

The invention belongs to the field of biomedical nanomaterials, and particularly relates to a viroid hollow manganese oxide loaded near-infrared dib region excited rare earth nanocrystal, a preparation method thereof and application of the viroid hollow manganese oxide loaded rare earth nanocrystal in surgical navigation and postoperative chemodynamic therapy.

Background

Among the current treatments for cancer, complete surgical resection is the most common and desirable method of choice. However, the current preoperative routine examination means for tumors is limited in self resolution, so that the position, the edge and micrometastases of the tumors are difficult to effectively judge and find, and the tumor cells remained after surgical resection can cause the postoperative tumors of patients to relapse. Accordingly, there is a need for an efficient imaging means for real-time, accurate, objective and precise location of tumor and finding micrometastasis in the surgical resection process, so as to assist clinicians in complete tumor resection to reduce the postoperative recurrence rate of patients, which is of great significance for improving the postoperative survival rate of tumor patients.

Fluorescent probes have high response speed and high detection sensitivity, so fluorescent imaging becomes one of the most effective ways for early tumor diagnosis, assisted surgical navigation, detection of recurrent or residual lesions, monitoring of curative effect and the like. Current fluorescence surgical navigation probes are focused primarily in the near-infrared range of the first window (the first window near-infrared region, NIR I, 650-900 nm). Due to the limitations of fluorescence tissue penetrability and signal to noise ratio of NIR I, NIR I is not suitable for fluorescence imaging of tumors located deep in organs, such as brain tumors, ovarian tumors, liver tumors, lymphatic metastases, etc. The research shows that: compared with the fluorescence of NIR I, the second window near-infrared light (NIR II, 1000-1700nm) has deeper tissue penetration depth, higher signal-to-noise ratio and lower light damage. Therefore, NIR II fluorescence imaging can be used to accurately locate tumor locations, clearly observe tumor margins and perform efficient resection.

The intelligent nano-carrier is adopted to deliver the medicine to the tumor part, and the medicine is specifically and controllably released to the canceration position under the stimulation of the special microenvironment or markers of the tumor by utilizing the difference between the tumor tissue and the normal tissue, so that the curative effect of tumor treatment can be improved, and the toxic and side effects can be reduced. Therefore, the precise and controllable release of the drug molecules can be realized through the specificity of the tumor cells. Manganese oxide is widely applied to tumor treatment, and manganese ions released by the manganese oxide through degradation can generate singlet oxygen in the tumor acidic environment to perform chemokinetic treatment and can also be used for nuclear magnetic resonance imaging. In addition, viroid silica nanoparticles having a rough surface can greatly increase the uptake rate of cells due to the adhesion of cells. Therefore, there is a need to develop a new method for constructing viroid metal mesoporous oxide, which is simple and has great significance for biological application and clinical transformation, to improve tumor cell uptake and biological safety.

Disclosure of Invention

In order to improve the technical problem, the invention provides a rare earth nanocrystal which comprises a carrier and rare earth core-shell nanoparticles loaded on the surface of the carrier.

According to the embodiment of the invention, in the rare earth nanocrystal, the mass ratio of the support to the rare earth core-shell nanoparticles is 1 (1-2), preferably 1 (1-1.5), and exemplarily 1:1, 1:1.2, 1:1.5 and 1:2.

According to an embodiment of the invention, the support and the rare earth core-shell nanoparticles are connected by a valence bond, for example by an amide bond.

According to an embodiment of the present invention, the support has an amino group, which forms an amide bond with a carboxyl group in the rare earth core-shell nanoparticle.

According to the embodiment of the invention, the rare earth nanocrystal can be selectively degraded in a tumor weak-acid microenvironment, preferably can be selectively degraded in the tumor weak-acid microenvironment to release manganese ions (Mn)²⁺) Iron ion (Fe)²⁺)。

According to an embodiment of the present invention, the carrier is a hollow sphere modified with an amino functional compound on the surface. For example, the carrier is amination modified hollow manganese oxide or hollow iron oxide.

Preferably, the compound having an amino functional group may be, for example, aminosilane APTES ((3-Aminopropyl) -triethoxysilane).

Preferably, the cavity of the carrier is loaded with a fluorescence quenching molecule. For example, the fluorescence quenching molecule can be a near infrared absorber, such as IR 1064. For another example, the loading amount of the fluorescence quenching molecule is 10-15% of the total weight of the carrier, and is exemplified by 10%, 12% and 15%.

Preferably, the hollow manganese oxide is a nanoparticle, has a virus-like shape, can be quickly phagocytized by tumor cells, and realizes accurate imaging and treatment of tumors.

The viroid hollow manganese oxide can be degraded and collapsed in the tumor acidic environment, and the released manganese ions can be used for chemokinetic treatment of tumor metastasis after operation or nuclear magnetic resonance imaging of tumors; after the fluorescent quenching molecule IR1064 is released, the fluorescence of the rare earth nanoparticles is recovered, so that the fluorescent quenching molecule can be used for the navigation resection of the fluorescent imaging operation of the tumor.

According to an embodiment of the invention, the rare earth core-shell nanoparticle comprises a core layer nanoparticle, at least one shell layer coated outside the core layer nanoparticle and a polymer containing a carboxyl functional group modified outside the shell layer, wherein the core layer nanoparticle and the shell layer are respectively and independently selected from AREF₄Wherein: a is Na or K, RE is Er, Ho, Gd or YAt least one of them.

Preferably, a is Na.

Preferably, the RE element in the core layer nanoparticle and the shell layer are different. Preferably, in the core layer nano-particles, RE is two of Er and Ho; in the shell layer nano-particles, RE is Y.

Preferably, the doping amount of Ho in the core layer nanoparticle is 1-5%, and is exemplarily 1%, 2%, 5%.

Preferably, the particle size of the rare earth core-shell nanoparticles is 24-25.5 nm, such as 24nm, 24.13nm, 25nm, 25.25nm and 25.5 nm.

Preferably, the ratio of the particle size of the core layer nanoparticles to the thickness of the shell layer is 1 (1-1.5), and is exemplarily 1:1, 1:1.18, 1: 1.5.

Preferably, the particle size of the core layer nano-particles is 17-18 nm, and is exemplified by 17.09nm, 17.5nm and 17.95 nm.

Preferably, the polymer containing carboxyl functional groups can be PEG polymer, small molecular acid or carboxyl-containing high molecular polymer, such as phospholipid polyethylene glycol (DSEP-PEG)₂₀₀₀-COOH), maleamic acid, polyacrylic acid, and the like.

The polymer containing carboxyl functional groups can enhance the biocompatibility of materials and reduce cytotoxicity.

Preferably, the rare earth core-shell nanoparticles have optical contrast functions of a near-infrared first region (650-900nm) and a near-infrared second region (1000-1700 nm).

According to an embodiment of the present invention, the rare earth nanocrystals are monodisperse and uniform in size. Preferably, the average particle size of the rare earth nanocrystals is about 24-26 nm, and is exemplified by 24.13nm, 24.69nm, 25nm, and 25.25 nm.

According to the embodiment of the invention, the rare earth nanocrystal can be excited by a near infrared dib region to generate near infrared first-region and near infrared second-region fluorescence emission.

For example, the rare earth nanocrystal can emit 660nm of near infrared-red light under 1532nm excitation. The fluorescence imaging device is used for near-infrared first-region fluorescence imaging and can be used as a reference for near-infrared second-region imaging.

For example, the rare earth nanocrystals can emit 1180nm fluorescence under 1532nm excitation. The method is used for surgical excision of near-infrared two-region fluorescence imaging navigation tumor, solves the problems of low resolution and potential penetration in current surgical navigation, and can be used for deep tissue background-free fluorescence imaging.

According to an embodiment of the invention, the rare earth core-shell nanoparticles may be, for example, β -NaErF₄: Ho@NaYF₄。

The rare earth nanocrystalline particles can achieve fluorescence imaging navigation tumor resection, fluorescence imaging guidance of postoperative metastasis, tumor photodynamic enhancement and nuclear magnetic resonance imaging of tumors, greatly improve tumor removal efficiency and provide guidance for clinical malignant tumor treatment.

The invention also provides a preparation method of the rare earth nanocrystalline, which comprises the step of reacting the carrier with the rare earth core-shell nano particles to prepare the rare earth nanocrystalline.

According to the embodiment of the invention, the mass ratio of the rare earth core-shell nanoparticles to the carrier is 2-5: 1, and is exemplified by 2:1, 3:1, 4:1 and 5: 1.

According to an embodiment of the present invention, the method for preparing rare earth core-shell nanoparticles comprises the following steps:

(1) adding rare earth salt into a mixed solution of oleic acid and octadecene, and then adding an alkali metal fluoride solution and an alkaline solution for reaction to obtain the core-layer nano-particles;

(2) and (2) adding RE-OA and A-TFA-OA precursor solution into the product obtained in the step (1) for reaction to prepare the rare earth core-shell nano-particles.

Preferably, step (2) is performed at least once to obtain nanoparticles coated with at least one shell layer. Illustratively, 1, 2, 3 or more times;

wherein, A is Na or K, RE is at least one of Er, Ho, Gd and Y, and Y is preferred.

Preferably, the alkali metal fluoride solution is NaF, NH₄One of solutions of F and KF,preferably NH₄And F solution.

Preferably, in step (1), the molar ratio of rare earth ions in the rare earth salt to alkali metal fluoride is 1 (2-5), illustratively 1: 4.

Preferably, the rare earth ions in the rare earth salt are at least one of Er, Ho and Y, and preferably two of Er and Ho.

Preferably, the molar ratio of the Er to the Ho is (48-49.5): (0.5-2), and is exemplified by 49.5:0.5, 49:1 and 48: 2.

Preferably, the step (1) further comprises dissolving the core layer nanoparticles in a solvent, for example, cyclohexane. For example, the concentration of the core layer nanoparticle dispersion may be 0.05 to 0.2mol/L, and is illustratively 0.1 mol/L.

Preferably, in step (1), the rare earth salt is a rare earth chloride, a rare earth nitrate or a rare earth acetate, preferably a rare earth acetate.

For example, the rare earth chloride is HoCl₃、ErCl₃And YCl₃At least one of (1).

For example, the rare earth nitrate is Ho (NO)₃)₃、Er(NO₃)₃And Y (NO)₃)₃At least one of (1).

For example, the rare earth acetate is Ho (CH)₃COO)₃、Er(CH₃COO)₃And Y (CH)₃COO)₃At least one of (1).

Preferably, in step (1), the alkaline solution is a sodium hydroxide solution or a potassium hydroxide solution.

Preferably, the solvent used in the alkali metal fluoride solution and the alkaline solution is methanol.

Preferably, in step (1), the total amount of the rare earth salt is 0.5-2 mmol, exemplary 0.5mmol, 1mmol, 2 mmol.

Preferably, in the step (1), the using amount ratio of the oleic acid to the octadecene is 1 (2-3), and is exemplarily 1:2, 1:2.5 and 1: 3.

Preferably, in the step (1), the method further comprises heating and stirring the mixed solution of oleic acid and octadecene after adding the rare earth salt to remove water and oxygen in the system. For example, the temperature of the heating and stirring is 130-150 ℃, exemplary is 130 ℃, 140 ℃ and 150 ℃; the heating and stirring time is 20-40 min. Exemplary are 20min, 30min, 40 min. Further, the heating and stirring are performed under vacuum conditions.

Preferably, in the step (1), the method further comprises stirring and nucleating a mixed solution after adding the alkali metal fluoride solution and the alkaline solution. For example, the stirring nucleation adopts a two-stage heating mode.

Preferably, in the two-stage heating mode:

the temperature of the first stage heating is 40-60 ℃, exemplary is 40 ℃, 50 ℃ and 60 ℃; the first-stage heating time is 0.5-2 h, and 0.5h, 1h and 2h are exemplified;

the temperature of the second heating is 60-80 ℃, exemplary 60 ℃, 70 ℃ and 80 ℃; the time of the second stage heating is 0.5-2 h, and 0.5h, 1h and 2h are exemplified.

Preferably, the preparation method further comprises a process of performing solid-liquid separation on the mixed solution of the core-layer nanoparticles prepared in the step (1) to obtain a reaction product. For example, the solid-liquid separation method is to add a precipitant to the mixed solution to perform precipitation, and centrifuge the mixed solution to obtain a solid product. As another example, the precipitant can be ethanol.

Preferably, the preparation method further comprises washing the reaction product obtained by the solid-liquid separation in the step (1). For example, the solvent for washing may be absolute ethanol.

Preferably, in the step (2), before adding the RE-OA and a-TFA-OA precursor solutions to the product of the step (1), the method further comprises adding the core layer nanoparticle dispersion solution to a mixed solution of oleic acid and octadecene. For example, the volume ratio of the core layer nanoparticle dispersion to the mixed solution of oleic acid and octadecene is 1 (1-3), and 1:2 is exemplified. As another example, in the mixed solution of oleic acid and octadecene, the volume ratio of oleic acid to octadecene is 1 (1-2), and an exemplary ratio is 1: 1.5.

Preferably, in the step (2), the concentration of the RE-OA precursor solution is 0.05-0.2 mol/L, and is exemplarily 0.05mol/L, 0.1mol/L, and 0.2 mol/L.

According to an exemplary embodiment of the present invention, the RE-OA precursor solution is prepared by dissolving a salt containing an RE element in a mixed solvent of oleic acid and octadecene. Preferably, the volume ratio of oleic acid to octadecene in the mixed solvent is 1 (1-2), and the volume ratio is 1:1, 1:1.5 and 1:2. Further, heating and stirring the mixed solution. For example, the heating temperature may be 130 to 150 ℃, exemplary 130 ℃, 140 ℃, 150 ℃; the heating time is 0.5-2 h, and 0.5h, 1h and 2h are exemplified. In another example, the salt containing the RE element is a rare earth chloride, a rare earth nitrate, or a rare earth acetate, preferably a chloride.

Preferably, in the step (2), the concentration of the A-TFA-OA precursor solution is 0.3-0.5 mol/L, and is exemplified by 0.3mol/L, 0.4mol/L and 0.5 mol/L.

According to an exemplary embodiment of the present invention, the a-TFA-OA precursor solution is prepared by dissolving a trifluoroacetate salt containing element a in oleic acid. Preferably, the preparation of the a-TFA-OA precursor solution further comprises stirring the mixed solution.

Preferably, in the step (2), the RE-OA precursor solution and the a-TFA-OA precursor solution are added to the core-layer nanoparticle dispersion liquid prepared in the step (1) in an alternating interval manner. For example, the RE-OA precursor solution and the A-TFA-OA precursor solution are alternately added at least once. Illustratively, each addition is alternated 1, 2 or more times; preferably three times each. As another example, the interval time may be 10-20 min, for example, 10min, 15min, 20 min.

Preferably, the molar ratio of the rare earth salt to the rare earth ions and the oleic acid in the RE-OA precursor solution in the step (2) is 1 (6-8), and is exemplarily 1:6, 1:7.5 and 1: 8.

Preferably, the reactions of step (1) and step (2) are carried out under an inert atmosphere. For example, the inert atmosphere is nitrogen or argon.

Preferably, in steps (1), (2), the temperature of the reaction is the same or different, 200 and 400 ℃ independently of each other, exemplary 200 ℃, 280 ℃, 300 ℃, 400 ℃. Preferably, in step (1), the reaction time is 40-80min, exemplary 40min, 60min, 80 min.

Preferably, in steps (1), (2), the reaction is heated at a rate of 5-20 deg.C/min, illustratively 5 deg.C/min, 10 deg.C/min, 20 deg.C/min.

Preferably, the preparation method further comprises step (3): and (3) uniformly mixing the nano-particles coated with at least one shell layer obtained in the step (2) and a polymer containing carboxyl functional groups in an organic solvent, standing until the organic solvent is volatilized, then adding water for dispersing, and centrifugally separating out the carboxyl modified rare earth core-shell nano-particles.

Preferably, in step (3), the organic solvent is chloroform, cyclohexane, n-hexane, tetrahydrofuran, preferably chloroform.

Preferably, in the step (3), the centrifugal separation rotation speed is 8000-20000 rpm, exemplary 8000rpm, 10000rpm, 15000rpm, 17500rpm, 20000 rpm. Further, the centrifugation time is 20-40 min, and 20min, 30min and 40min are exemplified.

Further, in the step (3), the ratio of the amount of the nanoparticle coated with at least one shell layer to the amount of the polymer having a carboxyl functional group is 0.1mmol (20-30) mg, and exemplary amounts are 0.1mmol:20mg, 0.1mmol: 25mg, and 0.1mmol:30 mg.

According to an exemplary embodiment of the present invention, the method for preparing the rare earth nanocrystal includes the steps of:

(A1)β-NaErF₄preparation of 2% Ho core layer

Er (CH)₃CO₂)₃·4H₂O、Ho(CH₃CO₂)₃·4H₂Adding O into the mixed solution of oleic acid and octadecene, uniformly mixing, heating and stirring under a vacuum condition (removing water and oxygen in the system), and finally cooling to room temperature to obtain a clear and transparent solution; then adding ammonium fluoride and a methanol solution of sodium hydroxide, keeping the mixture for 0.5 to 2 hours at the temperature of between 40 and 60 ℃, fully stirring the mixture for nucleation, heating the mixture to between 60 and 80 ℃, and carrying outKeeping the reaction solution under vacuum for 0.5-2 h (removing redundant methanol, oxygen and water molecules); then, reacting for 50-70 min at 300 ℃ under the protection of argon;

(A2) preparation of the precursor

Synthesis of a Y-OA precursor: mixing YCl₃Dissolving in a mixed solvent of oleic acid and octadecene, heating and stirring under the condition of keeping vacuum to prepare a clear and transparent Y-OA precursor solution;

② synthesizing Na-TFA-OA precursor: dissolving sodium trifluoroacetate in oleic acid, mixing, vacuumizing, and uniformly stirring until the sodium trifluoroacetate is completely dissolved to obtain a light yellow transparent precursor oleic acid solution;

(3)NaYF₄the package is prepared by adopting a continuous layer-by-layer growth method

First NaErF₄Adding 2% Ho core layer nanoparticle dispersion liquid into a mixed solution of oleic acid and octadecene, removing cyclohexane from a system under vacuum, introducing argon, heating, and then alternately adding Y-OA and Na-TFA-OA precursor solutions to prepare the luminescent rare earth nanocrystal.

According to the embodiment of the invention, the preparation method of the carrier comprises the steps of taking the viroid silicon mesoporous nanoparticles as a template, reacting with manganese salt and urotropine, and removing the viroid silicon mesoporous nanoparticle template through alkali treatment to obtain the viroid hollow manganese oxide.

According to an exemplary embodiment of the present invention, the viroid silicon mesoporous nanoparticles are prepared by a reaction of tetraethyl orthosilicate with cetyltrimethylammonium bromide (CTAB) and triethylamine.

Preferably, the tetraethyl orthosilicate and the cetyltrimethylammonium bromide (CTAB) are added into the reaction system in the form of solution. For example, a cyclohexane solution containing tetraethyl orthosilicate and an aqueous solution of cetyltrimethylammonium bromide (CTAB) are prepared separately. Preferably, the viroid silicon mesoporous nanoparticles are obtained by mixing aqueous solution of cetyltrimethylammonium bromide (CTAB) with triethylamine, then mixing with cyclohexane solution of tetraethyl orthosilicate, and reacting.

According to an exemplary embodiment of the invention, the amount ratio of tetraethyl orthosilicate to cetyltrimethylammonium bromide (CTAB) and triethylamine is 5.3mL:2g:1 mL.

According to an exemplary embodiment of the invention, the concentration of triethylamine may be 10-30%, exemplary 10%, 25%, 30%.

Preferably, the preparation method of the viroid silicon mesoporous nanoparticles further comprises a step of performing solid-liquid separation on the prepared viroid silicon mesoporous nanoparticles. For example, the solid-liquid separation may be by means known in the art, such as filtration, centrifugation.

Preferably, the preparation method further comprises washing the reaction product obtained by solid-liquid separation. For example, the solvent used for washing may be water or ethanol. As another example, the number of washes may be one, two, three.

Preferably, the reaction of the viroid silicon mesoporous nanoparticles with manganese salt and urotropin is carried out in a solvent system. For example, the viroid silicon mesoporous nanoparticles are dispersed in water, and then manganese salt and urotropine are added. For another example, the concentration of the viroid silicon mesoporous nanoparticle dispersion liquid is 1-3 mg/mL, and is exemplarily 1mg/mL, 2mg/mL, and 3 mg/mL.

According to an exemplary embodiment of the present invention, the mass ratio of the viroid silicon mesoporous nanoparticles to the manganese salt and the urotropin is 10:9: 9. Illustratively, the manganese salt may be Mn (NO)₃)₂·6H₂O。

According to an exemplary embodiment of the present invention, the temperature of the reaction of the viroid silicon mesoporous nanoparticles with manganese salt and urotropine is 80-100 ℃, exemplary 80 ℃, 90 ℃ and 100 ℃. Further, the reaction time is 3-5 h, and 3h, 4h and 5h are exemplified.

According to an exemplary embodiment of the present invention, the alkali solution used for the alkali treatment is an aqueous NaOH solution. Preferably, the temperature of the alkali treatment is 60-80 ℃, exemplary 60 ℃, 75 ℃ and 80 ℃. Further, the concentration of the alkali liquor is 1-3 mol/L, and examples are 1mol/L, 2mol/L and 3 mol/L.

Preferably, the preparation method of the viroid mesoporous manganese oxide further comprises the step of performing solid-liquid separation on the prepared viroid mesoporous manganese oxide reaction liquid. For example, the solid-liquid separation may be by means known in the art, such as filtration, centrifugation.

Preferably, the preparation method of the viroid mesoporous manganese oxide further comprises washing a reaction product obtained by solid-liquid separation. For example, the solvent used for washing may be water or ethanol. As another example, the number of washes may be one, two, three.

Preferably, the preparation method of the viroid mesoporous manganese oxide further comprises the step of reacting the washed reaction product with a compound containing an amino functional group to prepare the viroid mesoporous manganese oxide with the amino functional group modified on the surface.

Preferably, the preparation method of the viroid mesoporous manganese oxide further comprises the step of reacting the viroid mesoporous manganese oxide with the amino functional group modified on the surface with the fluorescence quenching molecule to prepare the viroid mesoporous manganese oxide with the amino functional group modified on the surface and loaded with the fluorescence quenching molecule. For example, the mass ratio of the viroid mesoporous manganese oxide with the amino functional group modified on the surface to the fluorescence quenching molecule is (3-5): 1, and exemplarily 3:1, 4:1, and 5: 1. As another example, the reaction time is not less than 12 hours, illustratively 24 hours.

Preferably, the preparation method of the viroid mesoporous manganese oxide further comprises the step of performing solid-liquid separation on the viroid mesoporous manganese oxide which is loaded with the fluorescence quenching molecules and is modified with amino functional groups on the surface. For example, the solid-liquid separation may be by means known in the art, such as centrifugation.

According to an embodiment of the present invention, the method for preparing the carrier comprises the steps of:

(S1) synthesizing viroid silicon mesoporous nanoparticles by a two-phase method;

cetyl Trimethyl Ammonium Bromide (CTAB) is dissolved in water, and then mixed solution of triethylamine, cyclohexane and tetraethyl orthosilicate is added to prepare the viroid silicon particles through reaction;

(S2) preparation of viroid hollow manganese oxide

Adding Mn (NO) into the viroid silicon mesoporous nano-particle dispersion liquid under the condition of heating and stirring₃)₂·6H₂O and urotropine, centrifugally washing after reaction, and finally etching off the viroid mesoporous silicon template in NaOH aqueous solution to prepare hollow viroid manganese oxide; reacting the viroid hollow manganese oxide with a compound containing an amino functional group to prepare viroid mesoporous manganese oxide with the amino functional group modified on the surface;

(S3) preparation of viroid hollow manganese oxide loaded with IR1064 surface connected rare earth nanocrystals

And (S2) dissolving the viroid hollow manganese oxide particles prepared in the step (S2) in water, then adding IR1064, stirring for reaction at room temperature, and then centrifuging to remove the redundant IR1064, thereby preparing the viroid hollow manganese oxide particles loaded with the IR1064 surface connected with the rare earth nanocrystals.

According to an embodiment of the present invention, in the method for preparing rare earth nanocrystals, the reaction of the support with the rare earth core-shell nanoparticles further comprises adding an activator. For example, the activator may be at least one of carbodiimide (EDC), N-hydroxysuccinimide (NHS), and Dimethylacetamide (DMAC); illustratively, the activators are EDC and NHS.

Preferably, the activation of the activator is carried out in a solution having a pH of 8.0 to 9.0 (exemplary pH 8.5). Further, the activation time is not less than 10h, and is exemplified by 12 h.

Preferably, the mass ratio of the rare earth core-shell nanoparticles to the activator is 1: 3-5.

Preferably, the mass ratio of the rare earth core-shell nanoparticles to the carrier is 2-5: 1.

The invention also provides a composite probe which contains the rare earth nanocrystalline.

The invention also provides application of the rare earth nanocrystalline or the composite probe in preparation and/or serving as a contrast agent in the fields of operation navigation (such as fluorescence imaging navigation tumor resection), postoperative chemodynamic treatment, postoperative fluorescence guidance of metastatic foci, nuclear magnetic resonance imaging of tumors and the like.

For example, the rare earth nanocrystals are used in the preparation and/or as near-infrared two-region optical contrast agents/nuclear magnetic resonance contrast agents.

Preferably, the near-infrared two-region optical contrast agent is applied to blood vessel imaging and lymph node imaging.

Preferably, when the optical contrast agent is used as a near-infrared two-region optical contrast agent, the emission wavelength is 1000-1700nm, and the excitation wavelength is 700-1100 nm.

The invention has the beneficial effects that:

(1) the method utilizes hydrothermal solvothermal synthesis to obtain rare earth nanocrystals excited by a near-infrared region II and emitted by a near-infrared region II; and the viroid mesoporous silicon dioxide is used as a hard template to synthesize the viroid hollow manganese oxide. And further loading a fluorescence quenching molecule IR1064 in the cavity of the viroid hollow manganese oxide. And finally, modifying the rare earth nanocrystals to the surface of the viroid hollow manganese oxide through a condensation reaction between amino and carboxyl so as to construct a composite probe for surgical navigation and postoperative photodynamic therapy. Because the manganese oxide has acidic environment responsiveness, the chemokinetic treatment of the transfer focus can be realized, and simultaneously, the manganese ions can be used for nuclear magnetic resonance imaging and the fluorescence of the released rare earth nanocrystals can be recovered. The material of the invention has the advantages of high tissue penetrability, no background auto-fluorescence interference, high resolution and the like, thus being applicable to the early diagnosis of clinical tumors, the fluorescence imaging of a near-infrared two-region tumor, the navigation tumor excision and the guide of the chemodynamic treatment of a metastatic focus, which have no background interference, high resolution and strong tissue penetrability.

(2) The invention synthesizes the rare earth nanocrystalline which is excited by a near-infrared region II b, emits red light, is monodisperse and has uniform size by doping regulation by using a hydrothermal solvothermal method, thereby realizing high penetration and high resolution imaging of tumor tissues and photodynamic therapy of tumor metastasis.

(3) The viroid manganese oxide nanoparticles synthesized by the method can be phagocytized by tumor cells in a large amount, and degraded in the micro-acid environment of the tumor cells to release singlet oxygen and manganese ions, so that the viroid manganese oxide nanoparticles can be used for chemokinetic treatment and nuclear magnetic resonance imaging of tumors to realize accurate treatment of the tumors.

(4) The viroid hollow manganese oxide-loaded near-infrared secondary region-excited rare earth nanocrystalline composite probe synthesized by the invention can realize fluorescence imaging of tumor microenvironment response, navigation tumor resection and photodynamic therapy of metastasis so as to thoroughly eliminate tumors, thereby improving the postoperative survival rate of patients and providing reference for clinical therapy of malignant tumors.

Drawings

A, B in FIG. 1 are the nuclei of the near-infrared dib-excited rare earth nanocrystals (β -NaErF) prepared in example 1₄2% Ho) and beta-NaErF₄:2％Ho@NaYF₄Transmission electron microscopy of nanocrystalline core-shell structures.

A, B in FIG. 2 are transmission electron micrographs of the viral silicon nanoparticles and the viroid hollow manganese oxide prepared in example 2, respectively.

A, B in FIG. 3 are respectively rare earth nanocrystals (MnO) excited by IR 1064-loaded viroid hollow manganese oxide surface-modified near-infrared dib region prepared in example 3₂-IR1064@β-NaErF₄:2％Ho@NaYF₄) Transmission electron microscope image and near infrared dib region excited rare earth nanocrystalline (beta-NaErF)₄:2％Ho@NaYF₄Core-shell structure and composite probe (MnO)₂-IR1064@β-NaErF₄:2％Ho@NaYF₄) Fluorescence spectrum of (2).

FIG. 4 shows the viroid manganese oxide particle-supported nanocrystal composite probe (MnO) prepared in example 3₂-IR1064@β-NaErF₄:2％Ho@NaYF₄) Transmission electron micrographs after incubation at pH 5.5 and 7.0, respectively, for different periods of time.

FIG. 5 shows the rare earth nanocrystal composite probe (MnO) loaded with the viroid manganese oxide particles prepared in example 3₂-IR1064@β-NaErF₄:2％Ho@NaYF₄) And fluorescence imaging contrast plots of clinically approved ICG penetration depths under different laser exposures.

Detailed Description

The technical solution of the present invention will be further described in detail with reference to specific embodiments. It is to be understood that the following examples are only illustrative and explanatory of the present invention and should not be construed as limiting the scope of the present invention. All the technologies realized based on the above-mentioned contents of the present invention are covered in the protection scope of the present invention.

Unless otherwise indicated, the raw materials and reagents used in the following examples are all commercially available products or can be prepared by known methods.

Example 1

β-NaErF₄:2％Ho@NaYF₄Preparing core-shell structure nanocrystals:

first Er (CH) in a molar ratio of 49:1₃CO₂)₃·4H₂O(408.123mg)，Ho(CH₃CO₂)₃·4H₂O (9.000mg), 1mmol of rare earth raw material, 6mL of oleic acid and 15mL of octadecene are sequentially added into a 100mL three-necked bottle and uniformly mixed, the mixture is heated to 140 ℃ under the vacuum condition, the stirring is kept for 30min, and water and oxygen in the system are removed. Finally, cooling to room temperature to obtain a clear and transparent solution. Respectively dissolving 4mmol of ammonium fluoride and 2.5mmol of sodium hydroxide in 5mL of methanol, quickly mixing, adding the clear and transparent solution, keeping at 50 ℃ for 1h, fully stirring for nucleation, then heating to 70 ℃, and keeping under vacuum for 60min (removing redundant methanol, oxygen and water molecules). Then, high-purity argon gas was introduced into the solution system while heating to 300 ℃ (heating rate of 10 ℃/min) and maintaining for 60 min. (magnetic stirring was maintained throughout the preparation). And finally, cooling the reacted system to room temperature, adding 15mL of absolute ethyl alcohol for precipitation, and performing high-speed centrifugation to obtain a product. The NaErF obtained is used₄ Washing 2% Ho nanocrystalline with absolute ethyl alcohol, centrifuging at 3000rpm for 10min, dispersing the separated solid product in cyclohexane, and freezing for later use, wherein the concentration is 0.1 mol/L.

Adopting a continuous layer-by-layer growth method (one-pot successful layer-by-layer protocol) to prepare the beta-NaErF₄:2％Ho@NaYF₄Core-shell structure nanocrystals:

synthesis of Y-OA (0.1M) precursor: adding 5.0mmol YCl₃Oleic acid (20.0mL) and octadecene (30.0mL) were added to a 100mL three-necked flask and mixed, the temperature was raised to 140 ℃ under vacuum, and stirring was maintained for 60min, keeping the system in a highly anhydrous oxygen environment. Then cooling the synthesized complex to obtain a clear and transparent precursor solution (0.1mol/L) of the Y-OA complex;

synthesis of Na-TFA-OA (0.4M) precursor: adding 16.0mmol of sodium trifluoroacetate and 40mL of oleic acid into a 100mL three-necked bottle, mixing, then placing at room temperature, vacuumizing and uniformly stirring until the components are completely dissolved to obtain a light yellow transparent precursor oleic acid solution;

core-shell structure beta-NaErF₄:2％Ho@NaYF₄The preparation of (1): firstly, 4.0mL of oleic acid and 6mL of octadecene are sequentially added into a 50mL three-necked bottle and uniformly mixed, and then 2.5mL of the synthesized beta-NaErF is added into the mixed solution ₄2% Ho in cyclohexane (0.25 mmol). Cyclohexane was removed from the system under vacuum, argon was passed through a three-necked flask, and the temperature was raised to 280 ℃ (the rate of temperature rise was 20 ℃/min). Then, alternately adding yttrium-oleic acid (Y-OA) (0.10mol/L, 1.0mL) and sodium trifluoroacetate-oleic acid (Na-TFA-OA) (0.40mol/L, 0.50mL) precursor solutions, wherein the dropping time interval between the two precursors is 15min, and obtaining the nano-particles coated with a shell layer after the dropping of the two precursors is finished; the total of three coating layers (i.e., repeating the alternate addition of yttrium-oleic acid (Y-OA) (0.10mol/L, 1.0mL) and sodium trifluoroacetate-oleic acid (Na-TFA-OA) (0.40M, 0.50mL) precursor solution three times) were coated, and the coating time interval between each layer was 15min, so the shell thickness could be controlled by the number of groups. After the reaction is finished, cooling the reaction mixed solution to room temperature to obtain the beta-NaErF₄:2％Ho@NaYF₄And centrifuging, washing and separating the nanocrystal by using absolute ethyl alcohol at 3000rpm for 10min, and dispersing a solid product obtained by separation into cyclohexane for freezing and storing for later use.

FIG. 1 shows the core (. beta. -NaErF) of the near infrared dib region excited rare earth nanocrystal prepared in this example₄2% Ho nanocrystal) and core-shell structure (beta-NaErF)₄:2％Ho@NaYF₄) Transmission electron micrograph (D). As can be seen from the figure, the nanocrystals of the core layer and the core-shell layer each have a uniform structureA beta-shaped structure; and the grain size is uniform, wherein the grain size of the core layer is about 17.52 +/-0.43 nm, and the grain size of the rare earth nanocrystalline with the core-shell structure is about 24.69 +/-0.52 nm.

Example 2

Preparation of the IR1064 loaded viroid hollow mesoporous manganese oxide particle:

(1) synthesizing viroid silicon mesoporous nanoparticles by a two-phase method;

a100 mL flask was charged with 60mL of ultrapure water and 1.5g of cetyltrimethylammonium bromide (CTAB), dissolved, stirred at 60 ℃ for 0.5h, and then charged with 0.75mL of 25% triethanolamine. And after 0.5h, adding a mixed solution of 16 mL of cyclohexane and 4mL of tetraethyl orthosilicate, reacting for 48h, centrifuging at 10000rpm for 10min to obtain a precipitate, and washing with water and ethanol for three times respectively to obtain the viroid silicon mesoporous nanoparticles.

(2) Preparation of viroid hollow mesoporous manganese oxide

Ultrasonically dispersing 100mg of viroid silicon mesoporous nano particles prepared in the step (1) in 50mL of deionized water, and then adding 0.09g of Mn (NO)₃)₃·6H₂O, and stirring for 0.5h in an oil bath at 90 ℃ and at the rotating speed of 600 rpm. Then, 0.09g of urotropin was added thereto, and the reaction was continued for 2 hours with stirring. After the reaction is finished, the product is collected by centrifugal separation and washed by water and ethanol for three times respectively. Then etching in an alkaline solution to remove the silicon dioxide template, and specifically operating as follows: dispersing the reaction product into 2mol/L NaOH aqueous solution, placing the solution in a 60 ℃ oven for 24h, washing the solution with water and ethanol for three times respectively to obtain the final product viroid hollow mesoporous manganese oxide particles, and drying the particles for later use.

(3) Preparation of IR 1064-loaded viroid hollow manganese oxide

Dispersing 20mg of viroid hollow mesoporous manganese oxide particles in 20mL of water, then adding 5mg of IR1064, stirring at room temperature for 24h, and centrifuging at 3000rpm for 5min to remove redundant IR1064, thereby successfully obtaining the viroid hollow manganese oxide particles loaded with the IR 1064.

Fig. 2 is a transmission electron microscope image of the viroid silicon mesoporous nanoparticles prepared in the embodiment and the viroid hollow mesoporous manganese oxide synthesized based on the viroid silicon mesoporous nanoparticles. As can be seen from the figure, the viroid mesoporous silica structure is successfully prepared, the interior of the viroid mesoporous silica structure is of a mesoporous structure, cluster tubules grow on the surface of the viroid mesoporous silica structure, the whole viroid mesoporous silica structure is of a viroid structure, and simultaneously, the mesopores and the tubular body of the viroid mesoporous silica structure can be used for loading drug molecules; the viroid hollow mesoporous manganese oxide prepared by the subsequent hard template method successfully replicates the structure of viroid mesoporous silicon oxide, is similar to a virus shell, and has the functions of rapid cell infection and drug loading.

Example 3

Preparing a composite probe of the rare earth nanocrystalline excited by the near-infrared dib region on the surface of the hollow virus manganese oxide loaded with IR 1064:

(1) oleic acid-coated beta-NaErF prepared in example 1₄:2％Ho@NaYF₄Rare earth nanocrystals (0.1 mmol) were dispersed in 5mL of chloroform, and then 1mL of a solution containing 25mg of DSEP-PEG was added₂₀₀₀-chloroform solution of-COOH. After stirring the mixture in a glass bottle for 24h, the chloroform spontaneously evaporated off under an air atmosphere. After the chloroform had evaporated, the vial was placed in an oven at 50 ℃ for 0.5h to facilitate further evaporation of the chloroform. Finally, 5mL of deionized water is added into the hydrophilic carboxyl phospholipid modified rare earth nanocrystalline particles, and through ultrasonic treatment, the redundant carboxyl phospholipid is washed at least three times through an ultracentrifuge (17500rpm, 30 min). Some of the large agglomerates present after the centrifugal washing can be removed through a 0.22 μm sieve. Finally, carboxyl functionalized rare earth nanocrystalline dispersed in water can be obtained;

(2) dispersing 100mg of IR 1064-loaded viroid hollow manganese oxide nanoparticles prepared in example 2 in 50mL of ethanol, carrying out oil bath at 80 ℃, stirring for 0.5h, adding 100 μ L of aminosilane APTES ((3-Aminoprophyl) -triethoxylacene), reacting for 12h, collecting a sample, and washing with ethanol and water at 3000rpm for 10min for three times to obtain amino-modified IR 1064-loaded viroid hollow manganese oxide particles;

(3) mixing the carboxyl functionalized rare earth nanocrystal prepared in the step (1) and the amino modified IR 1064-loaded viroid hollow manganese oxide particle prepared in the step (2) (the mass ratio is 3:1) in a reactor containing 8mg of 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride (EDC) and10mg of N-hydroxysuccinimide (NHS) and pH 8.5 for 12h to prepare the composite probe (MnO) of the near infrared dib region excited rare earth nanocrystal loaded with the IR1064 virus-like hollow manganese oxide surface modified by the nano-particles₂-IR1064@β-NaErF₄:2％Ho@NaYF₄)。

A, B in FIG. 3 are respectively rare earth nanocrystals (MnO) excited by near infrared dib region modified by IR 1064-loaded viroid hollow manganese oxide surface prepared in this example₂-IR1064@β-NaErF₄:2％Ho@NaYF₄) Transmission electron microscope image and near infrared dib region excited rare earth nanocrystalline (beta-NaErF)₄:2％Ho@NaYF₄Core-shell structure) and composite probe (MnO)₂-IR1064@β-NaErF₄:2％Ho@NaYF₄Core-shell structure). It can be observed from the A picture that the rare earth nanocrystalline can be successfully attached to the surface of the viroid hollow manganese oxide, thereby proving the reliability of the amino carboxyl condensation reaction of the invention. As can be seen from the B diagram: the rare earth nanocrystalline prepared by the invention has strong emission in both 660nm light and near infrared regions under the excitation of 1532 nm; in the composite probe, because the IR1064 is loaded in the viroid hollow manganese oxide, the composite probe has a strong light absorption effect, and the fluorescence of the rare earth nanocrystal is quenched.

FIG. 4 shows the rare earth nanocrystals (MnO) loaded on the viroid manganese oxide particles prepared in this example₂-IR1064@β-NaErF₄:2％Ho@NaYF₄) After incubation at pH 5.5 and 7.0 for 0min, the pellet was centrifuged after 30min and 120 min to obtain transmission electron micrographs. The results in the figure show that: in the micro-acid environment of tumor, the viroid hollow manganese oxide of the composite probe can be degraded to release beta-NaErF₄:2％Ho@NaYF₄Rare earth nanocrystalline and IR1064, beta-NaErF₄:2％Ho@NaYF₄The fluorescence of the rare earth nanocrystal can not be absorbed by the IR1064, the fluorescence recovery can be used for imaging, and the released manganese ions can be used for chemokinetic treatment of tumor metastases.

Tissue penetration test: the 20% fat emulsion was diluted to 1% with water for use. Taking a hexagonal cuvette, and adding beta-NaErF with the same fluorescence intensity into the hexagonal cuvette₄:2％Ho@NaYF₄Rare earth nanocrystals and ICG solutions. And (3) taking a culture dish with the diameter of 3.5cm, respectively placing the hexagonal small dishes with the samples at the bottom of the culture dish, and fixing the hexagonal small dishes with the samples by using adhesive tapes. Will contain beta-NaErF₄:2％Ho@NaYF₄The rare earth nanocrystalline culture dish is placed under an InGaAs imager, excited at 1532nm, and photographed by an optical filter of 880nm and exposure of 20 mm. Fat emulsions with a concentration of 1% of different thickness (0mm, 2mm, 4mm, 6mm, 8mm, 10mm) were added dropwise with a pipette and photographed until no hexagonal dish was observed.

Setting ICG as a control group, exciting at 808nm, using an optical filter at 880nm, and taking a picture by exposure at 20 mm; the above experiment was repeated. Analyzing the signal-to-noise ratio by image J software to obtain the beta-NaErF excited by the dib region₄:2％Ho@NaYF₄The superiority of rare earth nanocrystals over clinically approved ICG in terms of penetration and signal-to-noise ratio.

FIG. 5 shows the rare earth nanocrystals (MnO) loaded on the viroid manganese oxide particles prepared in this example₂-IR1064@β-NaErF₄:2％Ho@NaYF₄) And comparison of clinically approved ICG penetration depths (procedure below). It can be seen from the figure that the viroid manganese oxide particle loaded rare earth nanoprobe (MnO) excited by the dib region prepared by the invention₂-IR1064@β-NaErF₄:2％Ho@NaYF₄) The penetration depth of the film can reach 10 mm; compared with the penetrability of ICG 6mm of the traditional clinical standard, the viroid manganese oxide particles excited by the invention in the dib region load rare earth nanocrystalline (MnO)₂-IR1064@β-NaErF₄:2％Ho@NaYF₄) There are significant advantages in tissue penetration.

The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiment. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The rare earth nanocrystal is characterized by comprising a carrier and rare earth core-shell nanoparticles loaded on the surface of the carrier.

Preferably, in the rare earth nanocrystal, the mass ratio of the carrier to the rare earth core-shell nanoparticles is 1 (1-2).

Preferably, the support and the rare earth core-shell nanoparticles are connected by a valence bond, for example, an amide bond.

Preferably, the carrier has an amino group that forms an amide bond with a carboxyl group in the rare earth core-shell nanoparticle.

Preferably, the rare earth nanocrystal can be selectively degraded in a tumor weak-acid microenvironment, preferably, can be selectively degraded in the tumor weak-acid microenvironment to release manganese ions (Mn)²⁺) Iron ion (Fe)²⁺)。

Preferably, the carrier is a hollow sphere with a surface modified with an amino functional group compound.

Preferably, the carrier is amination-modified hollow manganese oxide or hollow iron oxide.

Preferably, the cavity of the carrier is loaded with a fluorescence quenching molecule.

Preferably, the fluorescence quenching molecule may be IR 1064.

Preferably, the loading amount of the fluorescence quenching molecules is 10-15% of the total weight of the carrier.

2. The rare earth nanocrystal of claim 1, wherein the rare earth core-shell nanoparticle comprises a core layer nanoparticle, at least one shell layer coated outside the core layer nanoparticle, and a polymer with a carboxyl functional group modified outside the shell layer, wherein the core layer nanoparticle and the shell layer are each independently selected from AREF₄Wherein: a is Na or K, and RE is at least one of Er, Ho, Gd and Y.

Preferably, a is Na.

Preferably, the RE element in the core layer nanoparticle and the shell layer are different.

Preferably, in the core layer nano-particles, RE is two of Er and Ho; in the shell layer nano-particles, RE is Y.

Preferably, in the core layer nanoparticles, the doping amount of Ho is 1-5%.

Preferably, the particle size of the rare earth core-shell nanoparticles is 24-25.5 nm.

Preferably, the ratio of the particle size of the core layer nano particles to the thickness of the shell layer is 1 (1-1.5).

Preferably, the particle size of the core layer nano particles is 17-18 nm.

3. The preparation method of the rare earth nanocrystal of claim 1 or 2, which is characterized by comprising the step of reacting a carrier with the rare earth core-shell nanoparticle to prepare the rare earth nanocrystal.

4. The method of claim 3, wherein the method of preparing the rare earth core-shell nanoparticle comprises the steps of:

Preferably, step (2) is performed at least once to obtain nanoparticles coated with at least one shell layer.

5. The method of claim 4, wherein the alkali metal fluoride solution isIs NaF, NH₄One of solutions of F and KF.

Preferably, in the step (1), the molar ratio of the rare earth ions in the rare earth salt to the alkali metal fluoride is 1 (2-5).

Preferably, the molar ratio of the Er to the Ho is (48-49.5): (0.5-2).

Preferably, the step (1) further comprises dissolving the core layer nanoparticles in a solvent, for example, cyclohexane. For example, the concentration of the core layer nanoparticle dispersion liquid may be 0.05 to 0.2 mol/L.

Preferably, in step (1), the rare earth salt is a rare earth chloride, a rare earth nitrate or a rare earth acetate.

Preferably, in the step (1), the total amount of the rare earth salt is 0.5-2 mmol.

Preferably, in the step (1), the using ratio of the oleic acid to the octadecene is 1 (2-3).

Preferably, in the step (1), the method further comprises heating and stirring the mixed solution of oleic acid and octadecene after adding the rare earth salt to remove water and oxygen in the system. For example, the heating and stirring temperature is 130-150 ℃, and the heating and stirring time is 20-40 min.

Preferably, in the two-stage heating mode:

the temperature of the first-stage heating is 40-60 ℃, and the time of the first-stage heating is 0.5-2 h;

the temperature of the second-stage heating is 60-80 ℃, and the time of the second-stage heating is 0.5-2 h.

6. The method of claim 4 or 5, wherein the step (2) further comprises adding the core layer nanoparticle dispersion to a mixed solution of oleic acid and octadecene before adding the RE-OA and a-TFA-OA precursor solutions to the product of the step (1).

Preferably, the volume ratio of the core layer nanoparticle dispersion liquid to the mixed solution of oleic acid and octadecene is 1 (1-3).

Preferably, the volume ratio of the oleic acid to the octadecene in the mixed solution of the oleic acid and the octadecene is 1 (1-2).

Preferably, in the step (2), the concentration of the RE-OA precursor solution is 0.05-0.2 mol/L.

Preferably, in the step (2), the concentration of the A-TFA-OA precursor solution is 0.3-0.5 mol/L.

Preferably, in the step (2), the RE-OA precursor solution and the a-TFA-OA precursor solution are added to the core-layer nanoparticle dispersion liquid prepared in the step (1) in an alternating interval manner.

Preferably, the RE-OA precursor solution and the A-TFA-OA precursor solution are alternately added at least once.

Preferably, the molar ratio of the rare earth salt to the rare earth ions and the oleic acid in the RE-OA precursor solution in the step (2) is 1 (6-8).

Preferably, in the steps (1), (2), the reaction temperature is the same or different, and is 200-400 ℃ independently from each other, and the reaction time is 40-80 min.

Preferably, in the steps (1) and (2), the temperature rising rate of the reaction is 5-20 ℃/min.

Preferably, in the step (3), the ratio of the nanoparticles coated with at least one shell layer to the polymer containing carboxyl functional groups is 0.1mmol (20-30) mg.

7. The preparation method of any one of claims 3 to 6, wherein the preparation method of the vector comprises the steps of taking the viroid silicon mesoporous nanoparticles as a template, reacting with manganese salt and urotropin, and removing the viroid silicon mesoporous nanoparticle template through alkali treatment to obtain the viroid hollow manganese oxide.

Preferably, the viroid silicon mesoporous nanoparticles are prepared by reacting tetraethyl orthosilicate with cetyltrimethylammonium bromide (CTAB) and triethylamine.

Preferably, the amount ratio of tetraethyl orthosilicate to cetyltrimethylammonium bromide (CTAB) and triethylamine is 5.3mL:2g:1 mL.

Preferably, the mass ratio of the viroid silicon mesoporous nanoparticles to the manganese salt and the urotropine is 10:9: 9.

Preferably, the reaction temperature of the viroid silicon mesoporous nanoparticles, manganese salt and urotropine is 80-100 ℃, and the reaction time is 3-5 h.

Preferably, the preparation method of the viroid mesoporous manganese oxide further comprises the step of reacting the viroid mesoporous manganese oxide with the amino functional group modified on the surface with the fluorescence quenching molecule to prepare the viroid mesoporous manganese oxide with the amino functional group modified on the surface and loaded with the fluorescence quenching molecule.

Preferably, the mass ratio of the viroid mesoporous manganese oxide with the amino functional group modified on the surface to the fluorescence quenching molecule is (3-5): 1.

Preferably, the preparation method of the carrier comprises the following steps:

(S2) preparation of viroid hollow manganese oxide

8. The method of any one of claims 3-7, wherein the reacting the support with the rare earth core-shell nanoparticles further comprises adding an activator.

Preferably, the activator may be at least one of carbodiimide (EDC), N-hydroxysuccinimide (NHS), and Dimethylacetamide (DMAC).

Preferably, the activating process of the activating agent is carried out in a solution with the pH value of 8.0-9.0.

9. A composite probe comprising the rare earth nanocrystal according to claim 1 or 2 and/or the rare earth nanocrystal produced by the production method according to any one of claims 3 to 8.

10. The rare earth nanocrystal of claim 1 or 2, the rare earth nanocrystal prepared by the preparation method of any one of claims 3 to 8, and/or the composite probe of claim 9 is prepared in the fields of surgical navigation, postoperative chemodynamic therapy, postoperative fluorescence guidance of metastasis, nuclear magnetic resonance imaging of tumors, and/or is used as a contrast agent.