Polypeptide-based aqueous-phase circularly polarized luminescent material and preparation method thereof

Abstract

The invention provides a polypeptide-based water-phase circular polarization luminescent material and a preparation method thereof, and relates to the technical field of photo-electromagnetic functional high polymer materials. The polymer is prepared by taking alpha-amino acid-N-carboxyl anhydride as a monomer through a ring-opening polymerization method. The water-phase dispersed nanoring is prepared by utilizing the polypeptide to perform self-assembly in a tetrahydrofuran / water phase through a solvent exchange method and a dialysis method, the water-phase dispersed nanoring shows obvious circular polarization luminescence performance, and the inversion of a circular polarization luminescence signal of a water-phase nanoring solution can be realized by regulating and controlling the chirality of the polymer; the amplification of a circular polarization signal can be realized by adopting a small molecule and polypeptide co-assembly method.

Description

Technical Field

[0001] The invention relates to the field of optical and electromagnetic functional polymer materials, and in particular to a poly(polypeptide-based) aqueous phase circularly polarized luminescent material and a preparation method thereof. Background Art

[0002] In recent years, circularly polarized luminescent materials based on biomolecules have been favored in the field of biomedicine (such as bioimaging, biosensing, etc.) due to the inherent chiral characteristics and diverse molecular conformations of biomolecules. Compared with solid-phase (gel, film, etc.) circularly polarized luminescent materials, circularly polarized luminescent nanoparticles dispersed in water have broader prospects in practical biomedical applications. However, the relevant research on water-dispersed bio-based circularly polarized luminescent nanomaterials is still in its early stages, and it is difficult to achieve the organic combination of circularly polarized luminescence technology with the current more mature nanoparticle diagnosis and treatment system, thus hindering the further development of bio-based circularly polarized luminescent nanomaterials in the biomedical field. As a synthetic biomolecule, polypeptides have both molecular chirality and spatial structural chiral characteristics. In the process of constructing polypeptide high-level structures by solution self-assembly, the spatial structure of the polypeptide chain can be switched or transformed, making it possible to construct aqueous nanomaterials with circularly polarized luminescent properties.

[0003] Based on this, the preparation of water-dispersed poly(peptide)-based circularly polarized luminescent materials is of great significance for promoting the application of circularly polarized luminescence technology in the biomedical field. Summary of the invention

[0004] The technical solution adopted by the present invention to solve the technical problem is to provide a method for preparing a poly(polypeptide)-based aqueous phase circularly polarized luminescent material, comprising the following steps:

[0005] Step (1): using a small molecule initiator to prepare a polypeptide by a ring-opening polymerization method using L-type or D-type α-amino acid-N-carboxyl ring anhydride as a monomer, wherein the small molecule initiator has aggregation-induced emission and reverse intramolecular charge transfer effects;

[0006] Step (2): dissolving the polypeptide in an organic solvent and leaving the solvent at room temperature for a first preset time to obtain an organic phase polypeptide solution;

[0007] Step (3): Stirring the organic phase polypolypeptide solution and adding deionized water to the organic phase polypolypeptide solution, and removing the organic solvent by dialysis to obtain a first aqueous phase dispersion, wherein the first aqueous phase dispersion has circularly polarized luminescence properties.

[0008] In the preparation method provided by the present invention, the structural formula of the polypeptide is as follows, wherein C* is an L-type or D-type chiral carbon; and n is a positive integer of 100 to 200:

[0009]

[0010] In the preparation method provided by the present invention, the structural formula of the small molecule initiator is as follows:

[0011]

[0012] In the preparation method provided by the present invention, the synthesis of the small molecule initiator comprises the following steps:

[0013] Compound a and b are subjected to Suzukii coupling reaction to obtain compound c;

[0014] Deprotecting compound c under acidic conditions to obtain a crude product, and then separating it by column chromatography to obtain the small molecule initiator;

[0015] The structural formulas of compounds a, b and c are as follows:

[0016]

[0017] In the preparation method provided by the present invention, in step (2), the organic solvent is tetrahydrofuran, the concentration of the tetrahydrofuran is 0.1-1.0 mg / mL, and the first preset time is equal to or greater than 24 hours.

[0018] In the preparation method provided by the present invention, in step (3), the volume of the organic phase polypeptide solution is 1 to 3 mL, the stirring rate is 50 to 100 rpm, the dropping rate of deionized water is 0.2 to 0.5 mL / min, the dropping volume of deionized water is 2 to 6 mL, the frequency of water change during dialysis is 3 to 5 times a day, and the dialysis time is 2 to 5 days.

[0019] The preparation method provided by the present invention also includes:

[0020] Step (4): dissolving the polypolypeptide and the small molecule compound in an organic solvent at different mass ratios, and standing at room temperature for a second preset time to obtain a mixed solution of the polypolypeptide and the small molecule compound;

[0021] Step (5): Stirring the mixed solution of the polypolypeptide and the small molecule compound and adding deionized water to the mixed solution of the polypolypeptide and the small molecule, and removing the organic solvent by dialysis to obtain a second aqueous phase dispersion, wherein the second aqueous phase dispersion has adjustable circularly polarized luminescence properties.

[0022] In the preparation method provided by the present invention, in step (4), the organic solvent is tetrahydrofuran, the mass ratio of the polypolypeptide to the small molecule compound is 100:1 to 25:1, wherein the concentration of the polypolypeptide is 0.1 to 1.0 mg / mL, the concentration of the small molecule compound is 5 μg / mL to 20 μg / mL, the second preset time is equal to or greater than 24 hours, and the structure of the small molecule compound is as follows:

[0023]

[0024] In the preparation method provided by the present invention, in step (5), the volume of the mixed solution of the polypeptide and the small molecule compound is 1 to 3 mL, the stirring rate is 50 to 100 rpm, the dropping rate of deionized water is 0.2 to 0.5 mL / min, the dropping volume of deionized water is 2 to 6 mL, the frequency of water change during dialysis is 3 to 5 times a day, and the dialysis time is 2 to 5 days.

[0025] The present invention also provides a poly(polypeptide-based) aqueous phase circularly polarized luminescent material prepared according to the method for preparing the poly(polypeptide-based) aqueous phase circularly polarized luminescent material as described above.

[0026] The implementation of the present invention can achieve the following beneficial effects:

[0027] The present invention proposes a new aqueous polypolypeptide-based circularly polarized luminescent material and a preparation method thereof, wherein a luminescent chiral polypolypeptide is constructed, and then the chirality is successfully transferred by means of macromolecular self-assembly, thereby preparing aqueous-phase dispersed circularly polarized luminescent nanoparticles; the method is simple and convenient, and provides a new idea for the preparation of aqueous-phase circularly polarized luminescent materials; the circularly polarized luminescent signal of the system can be manipulated by the chirality of the polypolypeptide and the co-assembly strategy; the circularly polarized light signal can be reversed after the chirality of the polypolypeptide is converted; in the co-assembly system, the controllable amplification of the circularly polarized light signal can be achieved by changing the mass ratio of the polypolypeptide to the small molecule; in view of the fact that circularly polarized light can improve the signal-to-noise ratio in biological imaging and the relatively mature nanoparticle delivery diagnosis and treatment system in the current biomedicine field, the aqueous polypolypeptide-based circularly polarized luminescent material of the present invention has good application prospects in the biomedicine field. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below. Obviously, the drawings in the following description are only embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on the provided drawings without creative work:

[0029] Figure 1Shown is the synthesis route and H NMR spectrum of the small molecule initiator;

[0030] Figure 2 Shown is the synthetic route and H NMR spectrum of (L-type or D-type) polypeptide;

[0031] Figure 3 Shown are the morphology of nanoparticles in the water-phase polypeptide-based circularly polarized luminescent material constructed by self-assembly and the circularly polarized luminescence spectrum of the system;

[0032] Figure 4 Shown are the morphology of nanoparticles in the aqueous phase poly-polypeptide-based circularly polarized luminescent material constructed by co-assembly and the circularly polarized luminescence spectrum of the system. DETAILED DESCRIPTION

[0033] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific embodiments of the present invention are now described in detail with reference to the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments described in this specification, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Example 1 Preparation of small molecule initiator

[0035] The synthetic route of small molecule initiators is as follows Figure 1 (A) As shown. Compound a (1mmol), compound b (1.5mmol), potassium carbonate (4mmol) and tetrakistriphenylphosphine palladium (0.05mmol) were added to a 100mL double-necked round-bottom flask, and 50mL of tetrahydrofuran and 5mL of water were added. The mixture was then heated to reflux for 16h under nitrogen, cooled to room temperature, poured into water, and extracted three times with dichloromethane. The organic phase was washed with a saturated sodium chloride solution and dried over anhydrous magnesium sulfate. After filtration and solvent evaporation, it was purified by silica gel column chromatography to obtain compound c with a yield of 82%. The nuclear magnetic resonance data is shown in Figure 1 (B). Dissolve compound c (0.3 mmol) in 10 mL of dichloromethane, add 2 mL of trifluoroacetic acid at 0°C, react for 30 min, and then react at room temperature for 3 h. After the reaction, spin dry the solvent, then add 2 mL of methanol and 50 mL of sodium hydroxide solution (2M) and stir well, then extract with dichloromethane three times. Wash the organic phase with saturated sodium chloride solution and dry with anhydrous magnesium sulfate. After filtration and solvent evaporation, the small molecule initiator can be obtained with a yield of 91%. NMR data is shown in Figure 1 (C).

[0036] Example 2 Preparation of (L-type or D-type) Polypeptide

[0037] The synthetic route of (L-type or D-type) polypeptide is as follows Figure 2 (A) As shown. A small molecule initiator (0.04 mmol) and compound d or e (6.9 mmol) were added to a 25 mL single-necked round-bottom flask, and 5 mL of anhydrous N,N-dimethylformamide was added, and then reacted at 35°C with vacuum for 48 h. Afterwards, the mixture was precipitated in 100 mL of methanol and centrifuged to obtain a solid. The precipitation and centrifugation operation was repeated three times, and then the mixture was placed in a vacuum oven for drying to prepare (L-type or D-type) polypeptides. The NMR images are shown in FIG. Figure 2 (B) and 2 (C). The structural formulas of small molecules d and e are as follows:

[0038]

[0039] Example 3 Preparation of Polypeptide-Based Aqueous Circularly Polarized Luminescent Material

[0040] Take (L-type or D-type) polypolypeptide and dissolve it in tetrahydrofuran to make a 0.5 mg / mL solution and let it stand at 25°C for 24 hours. Then take 2 mL of the above organic solution and stir it at a rate of 50 rpm. Then add 4 mL of deionized water at a rate of 0.2 mL / min through a peristaltic pump. After the assembly is completed, transfer the solution to a dialysis bag with a molecular weight cutoff of 3500 for dialysis. The water is changed 3 times a day during the dialysis process, and the dialysis time is 3 days. The final prepared nanoparticles are nanorings ( Figure 3 (A)) and has obvious circularly polarized luminescence behavior ( Figure 3 (B) and (C)).

[0041] In this example, by constructing a luminescent chiral polypeptide, the chirality transfer was successfully achieved by means of macromolecular self-assembly, and circularly polarized luminescent nanoparticles dispersed in water were prepared; this method is simple and convenient, and provides a new idea for the preparation of aqueous circularly polarized luminescent materials.

[0042] Example 4 Performance Control of Polypeptide-Based Aqueous Circularly Polarized Luminescent Materials

[0043] Take (L-type or D-type) polypolypeptide and small molecule c and dissolve them in tetrahydrofuran to prepare a mixed solution of polymer and small molecule. The mass ratio of (L-type or D-type) polypolypeptide to small molecule c in the mixed solution is 100:1, 50:1, 25:1, respectively. The concentration of (L-type or D-type) polypolypeptide is 0.5 mg / mL, and the concentration of small molecule c is 5 μg / mL, 10 μg / mL, and 20 μg / mL, respectively. The mixed solution is allowed to stand at 25°C for 24 hours. Then take 2 mL of the above organic solution and stir it at a rate of 50 rpm. Then add 4 mL of deionized water at a rate of 0.2 mL / min through a peristaltic pump. After the assembly is completed, transfer the solution to a dialysis bag with a molecular weight cutoff of 3500 for dialysis. The frequency of water change during the dialysis process is 3 times a day, and the dialysis time is 3 days. The nanoparticles finally prepared are all nanorings ( Figure 4 (A)), and its circularly polarized luminescence performance is greatly improved and is positively correlated with the content of small molecule c ( Figure 4 (B) and (C)).

[0044] In this embodiment, the circularly polarized light signal can be reversed after the chirality of the polypolypeptide is converted; in the co-assembly system, the circularly polarized light signal can be controllably amplified by changing the mass ratio of the polypolypeptide to the small molecule; in view of the fact that circularly polarized light can improve the signal-to-noise ratio in biological imaging and the relatively mature nanoparticle delivery and treatment system in the current biomedical field, the aqueous phase polypolypeptide-based circularly polarized luminescent material in the present invention has good application prospects in the biomedical field.

[0045] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific embodiments. The above-mentioned specific embodiments are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can make many modifications without departing from the scope of protection of the present invention and the claims, all of which belong to the scope of protection of the present invention.

Claims

1. A method for preparing a poly(polypeptide)-based aqueous circularly polarized luminescent material, characterized in that: The following steps are involved: Step (1): using a small molecule initiator to prepare a polypeptide by a ring-opening polymerization method using L-type or D-type α-amino acid-N-carboxyl ring anhydride as a monomer, wherein the small molecule initiator has aggregation-induced emission and reverse intramolecular charge transfer effects; Step (2): dissolving the polypeptide in an organic solvent and leaving the solvent at room temperature for a first preset time to obtain an organic phase polypeptide solution; Step (3): Stirring the organic phase polypolypeptide solution and adding deionized water to the organic phase polypolypeptide solution, and removing the organic solvent by dialysis to obtain a first aqueous phase dispersion, wherein the first aqueous phase dispersion has circularly polarized luminescence properties.

2. The method for preparing the poly(polypeptide)-based aqueous circularly polarized luminescent material according to claim 1, characterized in that: The structural formula of the polypeptide is as follows, wherein C* is an L-type or D-type chiral carbon; and n is a positive integer of 100 to 200:

3. The method for preparing the poly(polypeptide)-based aqueous circularly polarized luminescent material according to claim 1, characterized in that: The structural formula of the small molecule initiator is shown below:

4. The method for preparing the poly(polypeptide)-based aqueous phase circularly polarized luminescent material according to claim 3, characterized in that: The synthesis of the small molecule initiator comprises the following steps: Compound a and b are subjected to Suzukii coupling reaction to obtain compound c; Deprotecting compound c under acidic conditions to obtain a crude product, and then separating it by column chromatography to obtain the small molecule initiator; Wherein, the structural formulas of compounds a, b and c are as follows:

5. The method for preparing the poly(polypeptide)-based aqueous circularly polarized luminescent material according to claim 1, characterized in that: In step (2), the organic solvent is tetrahydrofuran, the concentration of the tetrahydrofuran is 0.1-1.0 mg / mL, and the first preset time is equal to or greater than 24 hours.

6. The method for preparing the poly(polypeptide)-based aqueous circularly polarized luminescent material according to claim 1, characterized in that: In step (3), the volume of the organic phase polypeptide solution is 1 to 3 mL, the stirring rate is 50 to 100 rpm, the dropping rate of deionized water is 0.2 to 0.5 mL / min, the dropping volume of deionized water is 2 to 6 mL, the water change frequency during dialysis is 3 to 5 times a day, and the dialysis time is 2 to 5 days.

7. The method for preparing the poly(polypeptide)-based aqueous circularly polarized luminescent material according to claim 1, characterized in that: Also includes: Step (4): dissolving the polypolypeptide and the small molecule compound in an organic solvent at different mass ratios, and standing at room temperature for a second preset time to obtain a mixed solution of the polypolypeptide and the small molecule compound; Step (5): Stirring the mixed solution of the polypolypeptide and the small molecule compound and adding deionized water to the mixed solution of the polypolypeptide and the small molecule, and removing the organic solvent by dialysis to obtain a second aqueous phase dispersion, wherein the second aqueous phase dispersion has adjustable circularly polarized luminescence properties.

8. The method for preparing the poly(polypeptide)-based aqueous circularly polarized luminescent material according to claim 7, characterized in that: In step (4), the organic solvent is tetrahydrofuran, the mass ratio of the polypolypeptide to the small molecule compound is 100:1 to 25:1, wherein the concentration of the polypolypeptide is 0.1 to 1.0 mg / mL, the concentration of the small molecule compound is 5 μg / mL to 20 μg / mL, the second preset time is equal to or greater than 24 hours, and the structure of the small molecule compound is as follows:

9. The method for preparing the poly(polypeptide)-based aqueous circularly polarized luminescent material according to claim 7, characterized in that: In step (5), the volume of the mixed solution of the polypeptide and the small molecule compound is 1 to 3 mL, the stirring rate is 50 to 100 rpm, the dropping rate of deionized water is 0.2 to 0.5 mL / min, the dropping volume of deionized water is 2 to 6 mL, the frequency of water change during dialysis is 3 to 5 times a day, and the dialysis time is 2 to 5 days.

10. A polypolypeptide-based aqueous circularly polarized luminescent material prepared by the method for preparing a polypolypeptide-based aqueous circularly polarized luminescent material according to any one of claims 1 to 9.

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