阅读说明：本技术 一种通过原子转移自由基聚合制备的近红外二区荧光成像造影剂及其应用 (Near-infrared two-region fluorescence imaging contrast agent prepared through atom transfer radical polymerization and application thereof ) 是由 孙鹏飞 何坤 范曲立 陈尚钰 于 2021-07-05 设计创作，主要内容包括：本发明属于纳米生物医学成像技术领域,涉及一种高稳定性近红外二区荧光成像造影剂及其制备方法和应用。该水溶性造影剂由近红外二区荧光的有机小分子与水溶性单体通过原子转移自由基聚合而成后自组装而成。本发明制备的造影剂对碱性环境有好的稳定性、良好的水溶性和生物相容性,能够实现高清晰度的近红外二区荧光成像效果。(The invention belongs to the technical field of nano biomedical imaging, and relates to a high-stability near-infrared two-region fluorescence imaging contrast agent, and a preparation method and application thereof. The water-soluble contrast agent is formed by self-assembling after organic micromolecules with near-infrared two-region fluorescence and water-soluble monomers are polymerized by atom transfer free radicals. The contrast agent prepared by the invention has good stability to alkaline environment, good water solubility and biocompatibility, and can realize high-definition near-infrared two-region fluorescence imaging effect.)

1. A compound having the general structural formula:

in the formula (1), n is 5-30, and m is 5-20.

2. The compound of claim 1, wherein m is 5.

3. The compound of claim 1, wherein m is 10.

4. The compound of claim 1, wherein m is 20.

5. The method for preparing the compound according to any one of claims 1 to 4, wherein the compound is synthesized by atom transfer radical polymerization, and the synthesis route is as follows:

6. use of a compound according to any one of claims 1 to 4 for the preparation of a near-infrared two-zone fluorescence imaging contrast agent.

7. A near-infrared two-region fluorescence imaging contrast agent, which is prepared by dissolving the compound of any one of claims 1 to 4 in water and self-assembling in water.

8. The near-infrared two-zone fluorescence imaging contrast agent according to claim 7, wherein the concentration of the compound in the near-infrared two-zone fluorescence imaging contrast agent is 5-90 mg/ml.

9. The near-infrared two-region fluorescence imaging contrast agent according to claim 7 or 8, wherein the near-infrared two-region fluorescence imaging contrast agent can maintain photophysical stability within a pH range of 8-12 without decomposition and near-infrared two-region fluorescence reduction.

Technical Field

The invention belongs to the technical field of nano biomedical imaging, and particularly relates to a near-infrared two-region fluorescence imaging contrast agent prepared by atom transfer radical polymerization and application thereof.

Background

Near-infrared two-zone (900-.

In recent years, various inorganic materials, organic small molecules and conjugated polymers are used for preparing near-infrared two-region fluorescence imaging contrast agents. The organic small molecules are good in biocompatibility and easy to synthesize, can be metabolized from the inside of a living body, and can obtain different optical properties through structure regulation, so that the organic small molecules become development hotspots of near-infrared two-region fluorescence imaging contrast agents. Among the most interesting are small organic molecules of the electron donor-electron acceptor-electron donor (D-a-D) structure. However, such fractions developed today suffer from the problem of being susceptible to degradation in alkaline and redox environments. This poor stability problem also limits the possibility of water-soluble polymer modification of the polymer by atom transfer radical polymerization.

Disclosure of Invention

The purpose is as follows: the invention provides a near-infrared two-region fluorescence imaging contrast agent obtained by an atom transfer radical polymerization method, and a preparation method and application thereof, and aims to improve the light stability of the near-infrared two-region fluorescence imaging contrast agent in an alkaline environment, expand the application range of the near-infrared two-region fluorescence imaging contrast agent and realize a better fluorescence imaging effect.

The technical scheme is as follows: in order to solve the technical problems, the technical scheme adopted by the invention is as follows:

a compound having the general structural formula:

in the formula (1), the number n of block repeating units is 5 to 30, and m is 5 to 20.

In some embodiments, m is 5, 10, or 20. The corresponding water-soluble monomers are respectively:

the luminescent group of the compound is near-infrared two-region fluorescent dye, is 4, 6-bis (5'- (9, 9-dioctyl-9H-fluorene-2-yl) - [2,2' -bithiophene ] -5-yl) thiophene [3,4-C ] [1,2,5] thiadiazole, and has the following structure:

in a second aspect, the preparation method of the compound is provided, the compound is formed by atom transfer radical polymerization of a near-infrared two-region luminescent organic molecule TTDT-TF-Br modified by an atom transfer radical polymerization agent and a water-soluble monomer, and the synthetic route comprises the following steps:

in some embodiments, cuprous bromide is added as a catalyst, pentamethyldiethylenetriamine is used as a ligand, and anisole is used as a solvent during the preparation process; the reaction temperature is controlled to be 55-65 ℃, preferably about 60 ℃.

In a third aspect, the application of the compound in preparing a near-infrared two-region fluorescence imaging contrast agent is provided.

The near-infrared two-region fluorescence imaging contrast agent is obtained by directly dissolving the compound in water and self-assembling in the water.

Further, the concentration of the compound in the near-infrared two-region fluorescence imaging contrast agent is 5-90 mg/ml.

Furthermore, the near-infrared two-region fluorescence imaging contrast agent can keep photophysical stability within the pH value range of 8-12, and does not decompose and cause fluorescence reduction of the near-infrared two-region.

Has the advantages that: the invention designs and synthesizes a water-soluble near-infrared two-region fluorescence imaging contrast agent obtained by atom transfer radical polymerization, and the contrast agent is assembled by water-soluble polymers in aqueous solution. The near-infrared two-region luminescent group of the near-infrared two-region fluorescence imaging polymer is 4, 6-bis (5'- (9, 9-dioctyl-9H-fluorene-2-yl) - [2,2' -bithiophene ] -5-yl) thiophene [3,4-C ] [1,2,5] thiadiazole, and four water-soluble side chains are polyethylene glycol methacrylate with different structures. The preparation method is simple, the contrast agent has excellent near-infrared two-region imaging fluorescence effect, has good light stability in the range of pH value 8-12 and under redox conditions, and can not be decomposed. Compared with the currently reported near-infrared two-region fluorescence imaging contrast agent, the preparation method of the water-soluble near-infrared two-region fluorescence imaging polymer is atom transfer radical polymerization, and the method is simple and efficient in synthesis.

Drawings

FIG. 1 is a transmission electron micrograph of a contrast agent obtained in example 1 of the present invention in an aqueous solution;

FIG. 2 is a transmission electron micrograph of the contrast agent obtained in example 2 of the present invention in an aqueous solution;

FIG. 3 is a transmission electron micrograph of the contrast agent obtained in example 3 of the present invention in an aqueous solution

FIG. 4 shows the hydrodynamic diameter of the contrast agent obtained in example 4 of the present invention;

FIG. 5 shows the hydrodynamic diameter of the contrast agent obtained in example 5 of the present invention;

FIG. 6 shows the hydrodynamic diameter of the contrast agent obtained in example 6 of the present invention;

FIG. 7 is an absorption and fluorescence spectrum of the contrast agent obtained in example 2 of the present invention under different pH environments;

FIG. 8 is an absorption and fluorescence spectrum of a contrast agent obtained in example 3 of the present invention in a redox environment;

FIG. 9 shows the near-infrared two-zone fluorescence imaging of the contrast agent obtained in example 6 of the present invention on the mouse 4T1 tumor in vivo.

Detailed Description

To further illustrate the present invention, a series of examples are given below, which are purely illustrative and are intended to be a detailed description of the invention only and should not be understood as limiting the invention.

The synthesis method of the water-soluble near-infrared two-region fluorescence imaging polymer comprises the following steps:

when m is 5, the synthesis route of the near-infrared two-region fluorescence imaging polymer is as follows:

synthesis process

A5 ml reaction flask was taken, added with initiator TTDT-TF-Br (648 mg, 0.33 mmol), polyethylene glycol methacrylate monomer (2.16 g, 6.6 mmol), cuprous bromide (189 mg, 1.32 mmol), dissolved with anisole (2 ml), deoxygenated, added with pentamethyldiethylenetriamine (228 mg, 1.32 mmol), and reacted at 60 ℃ for 8 hours. Then, the mixture was precipitated with ethyl ether to obtain a reddish brown viscous liquid.

And adjusting the proportion of the monomers in the steps to obtain the water-soluble near-infrared two-zone fluorescence imaging polymer with the block repeating unit number n of 5-30.

When m is 10, the synthesis route of the near-infrared two-region fluorescence imaging polymer is as follows:

synthesis process

A5 ml reaction flask was taken, added with initiator TTDT-TF-Br (648 mg, 0.33 mmol), polyethylene glycol methacrylate monomer (4.32 g, 6.6 mmol), cuprous bromide (189 mg, 1.32 mmol), dissolved with anisole (2 ml), deoxygenated, added with pentamethyldiethylenetriamine (228 mg, 1.32 mmol), and reacted at 60 ℃ for 8 hours. Then, the mixture was precipitated with ethyl ether to obtain a reddish brown viscous liquid.

And adjusting the proportion of the monomers in the above steps to obtain the water-soluble near-infrared two-zone fluorescence imaging polymer with the block repeating unit number n of 5-30.

When m is 20, the synthesis route of the near-infrared two-region fluorescence imaging polymer is as follows:

synthesis process

A5 ml reaction flask was taken, added with initiator TTDT-TF-Br (648 mg, 0.33 mmol), polyethylene glycol methacrylate monomer (8.64 g, 6.6 mmol), cuprous bromide (189 mg, 1.32 mmol), dissolved with anisole (2 ml), deoxygenated, added with pentamethyldiethylenetriamine (228 mg, 1.32 mmol), and reacted at 60 ℃ for 8 hours. Then, the mixture was precipitated with ethyl ether to obtain a reddish brown viscous liquid.

And adjusting the proportion of the monomers in the process to obtain the water-soluble near-infrared two-zone fluorescence imaging polymer with the block repeating unit number n of 5-30.

Example 1:

and (3) dissolving 50 mg of polymer with m being 5 and the number n of the block repeating units being 5 in 5 ml of water to obtain the contrast agent by self-assembly.

As shown in FIG. 1, when the transmission electron microscopy image of the contrast agent in the aqueous solution is tested, the particle size of the contrast agent nanoparticle is 100-110 nm, and the contrast agent nanoparticle is all spherical-like.

Example 2:

and (3) dissolving 50 mg of polymer with m being 10 and the number n of the block repeating units being 10 in 5 ml of water to obtain the contrast agent by self-assembly.

As shown in FIG. 2, when the transmission electron microscopy image of the contrast agent in the aqueous solution is tested, the particle size of the contrast agent nanoparticle is 110-115 nm, and the contrast agent nanoparticle is all spherical-like.

As shown in FIG. 7, the absorption and emission spectra of the contrast agent are measured, and it can be seen that the UV-NIR absorption is in the range of 700 and 900 nm, and the emission peak is above 1000 nm, with significant two-window fluorescence emission. And the contrast agent has better light stability in solutions with different pH values.

Example 3:

and (3) dissolving 50 mg of polymer with m being 20 and the number n of the block repeating units being 20 in 5 ml of water to obtain the contrast agent by self-assembly.

As shown in FIG. 3, when the transmission electron microscopy image of the contrast agent in the aqueous solution is tested, the particle size of the contrast agent nanoparticle is 115-120 nm, and the contrast agent nanoparticle is spherical-like.

As shown in FIG. 8, the absorption and emission spectra of the contrast agent can be seen by testing the absorption and emission spectra of the contrast agent, wherein the ultraviolet-near infrared absorption is in the range of 700 nm and 900 nm, and the emission peak is above 1000 nm, which has obvious near infrared two-region fluorescence emission. And the contrast agent has better light stability in a redox environment.

Example 4:

and (3) dissolving 100 mg of polymer with m being 5 and the number n of the block repeating units being 5 in 5 ml of water to obtain the contrast agent by self-assembly.

As shown in fig. 4, the particle size of the contrast agent nanoparticle is 125 nm by testing the hydrodynamic diameter of the contrast agent in aqueous solution.

Example 5:

and (3) dissolving 200 mg of polymer with m being 5 and the number n of the block repeating units being 5 in 5 ml of water to obtain the contrast agent by self-assembly.

As shown in fig. 5, the particle size of the contrast agent nanoparticle is 130 nm by testing the hydrodynamic diameter of the contrast agent in aqueous solution.

Example 6:

and (3) dissolving 400 mg of polymer with m being 5 and the number n of the block repeating units being 5 in 5 ml of water to obtain the contrast agent by self-assembly.

As shown in fig. 6, the particle size of the contrast agent nanoparticle is 128 nm, which is obtained by testing the hydrodynamic diameter of the contrast agent in aqueous solution.

As shown in FIG. 9, a 4T1 tumor mouse model was selected, 200. mu.l was injected into the tail vein, and the signal intensity change of the tumor position of the mouse was observed by a near-infrared two-zone imager, which shows that the tumor was more and more clearly imaged with time, reaches a maximum value at 12 hours, and then the signal intensity begins to decrease with time.

The above description is only of the preferred embodiments of the present invention, and it should be noted that: it will be apparent to those skilled in the art that various modifications and adaptations can be made without departing from the principles of the invention and these are intended to be within the scope of the invention.