Fluorescent material as well as preparation method and application thereof

Abstract

The invention relates to a fluorescent material and a preparation method and application thereof, the fluorescent material has structural units shown as a formula I, a formula II and a formula III, the formula I is # imgabs 0 #, the formula II is # imgabs 1 #, the formula III is # imgabs 2 #, and R1, R2, R3, R4, R5, R6, R7, R8, R9, R10, R11, R12, R13, R14, R15 and R16 are respectively and independently selected from-H or-SO3H. The fluorescent material disclosed by the invention has the advantages of high brightness, good light stability and good biocompatibility, and is wide in application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of fluorescent materials, and in particular to a polyoxadiazole fluorescent material and a preparation method and application thereof. Background Art

[0002] Fluorescence labeling technology is increasingly used in the fields of biology and medicine, such as biomolecule detection, cell imaging, and drug delivery. However, existing fluorescent materials suffer from problems such as insufficient brightness, poor photostability, and limited biocompatibility. Therefore, there is an urgent need to develop new fluorescent materials to overcome these limitations and improve performance, thereby promoting the development of biological and medical research. Summary of the invention

[0003] The object of the present invention is to provide a novel fluorescent material having high brightness, excellent light stability and good biocompatibility.

[0004] The second object of the present invention is to provide a method for preparing the fluorescent material, which is simple and has relatively low cost.

[0005] The third object of the present invention is to provide an application of the fluorescent material.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] The first aspect of the present invention provides a fluorescent material, wherein the fluorescent material has structural units shown in Formula I, Formula II and Formula III.

[0008] The formula I is:

[0009]

[0010] The formula II is:

[0011]

[0012] The formula III is:

[0013]

[0014] Among them, R1, R2, R3, R4, R5, R6, R7, R8, R9, R 10 , R 11 , R 12 , R 13 , R 14 , R 15 , R 16 Each is independently selected from -H or -SO3H.

[0015] The fluorescent material of the present invention has structural units shown in Formula I, Formula II and Formula III at the same time, wherein the structural unit shown in Formula I can locate the absorption wavelength to ensure that the fluorescent emission wavelength of the fluorescent material reaches 500nm at a blue wavelength of 405nm, thereby better being compatible with existing light source equipment, optimizing optical performance, reducing interference, and enhancing the flexibility of multi-color labeling, and is suitable for experimental scenarios with high biocompatibility requirements; the structural unit described in Formula II can increase the fluorescence intensity and enhance the labeling effect of the fluorescent material; the structural unit shown in Formula III can enhance the solubility of the fluorescent material, thereby enabling the fluorescent material to be soluble in conventional organic solvents and improving the processability of the material.

[0016] Preferably, the molar ratio of the structural units represented by Formula I, Formula II and Formula III is (1-3):1:(6-10), and more preferably (1.5-2.5):1:(6-8).

[0017] Preferably, at least one of R1, R2, R3, and R4 is -SO3H.

[0018] Preferably, at least one of R5, R6, R7 and R8 is -SO3H.

[0019] Preferably, R9, R 10 , R 11 , R 12 At least one of the groups is -SO3H.

[0020] Preferably, the R 13 , R 14 , R 15 , R 16 At least one of the groups is -SO3H.

[0022] Preferably, the end groups of the fluorescent material are

[0023] The fluorescent material of the present invention has a maleimide end group, which has high selectivity for sulfhydryl groups (common in proteins, antibodies or other biomolecules), and is relatively insensitive to other functional groups (such as amino groups and carboxyl groups). This high selectivity reduces the occurrence of nonspecific reactions, enhances the accuracy of fluorescent labels, and helps to improve the accuracy and reliability of biomarker experiments. The maleimide end group and the sulfhydryl group can form a stable thioether bond, and this stability ensures the durability of the fluorescent label, so that the biomarker can maintain its function for a long time in vivo or in vitro. Therefore, the fluorescent material of the present invention can accurately label the target biomolecule and has the advantage of good stability. In addition, the fluorescent material of the present invention has good compatibility with other chemical groups, and can be combined with other reactive groups to design multifunctional markers.

[0024] The second aspect of the present invention also provides a method for preparing a fluorescent material, comprising reacting [1,1':4',1"-terphenyl]-4,4"-dicarboxylic acid, 9-oxo-9H-fluorene-2,7-dicarboxylic acid and 4,4'-biphenyl ether dicarboxylic acid with hydrazine sulfate in the presence of fuming sulfuric acid.

[0025] Preferably, the molar ratio of [1,1':4',1"-terphenyl]-4,4"-dicarboxylic acid, 9-oxo-9H-fluorene-2,7-dicarboxylic acid and 4,4'-biphenyl ether dicarboxylic acid is controlled to be (1-3):1:(6-10).

[0026] More preferably, the molar ratio of [1,1':4',1"-terphenyl]-4,4"-dicarboxylic acid, 9-oxo-9H-fluorene-2,7-dicarboxylic acid and 4,4'-biphenyl ether dicarboxylic acid is controlled to be (1.5-2.5):1:(6-8).

[0027] Preferably, the molar ratio of the total feed moles of [1,1':4',1"-terphenyl]-4,4"-dicarboxylic acid, 9-oxo-9H-fluorene-2,7-dicarboxylic acid and 4,4'-biphenyl ether dicarboxylic acid to the feed molar ratio of hydrazine sulfate is 1:(1-1.5), more preferably 1:(1-1.2), and even more preferably 1:(1-1.1).

[0028] Preferably, the [1,1':4',1"-terphenyl]-4,4"-dicarboxylic acid, 9-oxo-9H-fluorene-2,7-dicarboxylic acid, 4,4'-biphenyl ether dicarboxylic acid, hydrazine sulfate and fuming sulfuric acid are first dissolved at 60-90° C., and then reacted at 110-130° C. for 3-5 hours.

[0029] More preferably, the dissolving temperature is controlled to be 70-80°C.

[0030] More preferably, the reaction temperature is controlled to be 115-125° C., and the reaction time is 3.5-4.5 h.

[0031] Preferably, the preparation method further comprises adding a capping agent to cap the reaction product after the reaction is completed, so as to graft amino groups onto the reaction product, and then reacting the grafted reaction product with maleic anhydride.

[0032] In some embodiments, the end-capping agent is aminoterephthalic acid.

[0033] Preferably, the molar ratio of the end-capping agent to the total molar amount of the feed of [1,1':4',1"-terphenyl]-4,4"-dicarboxylic acid, 9-oxo-9H-fluorene-2,7-dicarboxylic acid and 4,4'-biphenyl ether dicarboxylic acid is (0.01-0.1):1, for example, 0.01:1, 0.02:1, 0.04:1, 0.06:1, 0.08:1, 0.1:1.

[0034] Preferably, the end-capping temperature is 110-130°C, more preferably 115-125°C.

[0035] Preferably, the preparation method further comprises, after the end-capping, washing the grafted reaction product with deionized water or alkaline solution until the grafted reaction product is neutral, and then drying it.

[0036] Preferably, the grafted reaction product is reacted with maleic anhydride in the presence of a cobalt catalyst and a dehydrating agent.

[0037] In some embodiments, the cobalt catalyst is cobalt acetate.

[0038] Preferably, the mass ratio of the grafted reaction product to the cobalt catalyst is 1:(0.1-0.3), and more preferably 1:(0.15-0.25).

[0039] In some embodiments, the dehydrating agent is acetic anhydride.

[0040] Furthermore, the mass volume ratio of the grafted reaction product to acetic anhydride is 1:(5-15), and more preferably 1:(8-12).

[0041] Preferably, the reaction temperature of the grafted reaction product and maleic anhydride is controlled to be 40-60°C, more preferably 45-55°C.

[0042] Preferably, the mass ratio of the grafted reaction product to maleic anhydride is controlled to be 1:(1-3), more preferably 1:(1.5-2.5), for example 1:1.5, 1:1.8, 1:2, 1:2.3, 1:2.5.

[0043] In some embodiments, the reaction system of the grafted reaction product and maleic anhydride further includes an organic solvent, and the organic solvent is nitrogen methyl pyrrolidone.

[0044] Furthermore, the mass ratio of the grafted reaction product to the organic solvent is (1-10):100.

[0045] The third aspect of the present invention provides an application of the fluorescent material mentioned above, wherein the application includes applying the fluorescent material to the fields of biomarker detection, cell imaging, drug delivery, in vitro diagnostic detection and biosensor.

[0046] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0047] The fluorescent material of the present invention has the advantages of high brightness, good photostability and good biocompatibility, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 is a schematic diagram of the reaction process of the fluorescent material in Example 1;

[0049] Figure 2 is the fluorescence emission spectrum of the fluorescent material of Example 1 under 405 nm excitation;

[0050] Figure 3 This is a real image of the fluorescent material of Example 1 under 405nm excitation;

[0051] Figure 4 The ultraviolet absorption spectrum of the fluorescent material of Comparative Example 3;

[0052] Figure 5 This is the ultraviolet absorption spectrum of the fluorescent material of Comparative Example 4. DETAILED DESCRIPTION

[0053] The present invention is further described below in conjunction with the examples. However, the present invention is not limited to the following examples. The implementation conditions used in the examples can be further adjusted according to the different requirements of specific use, and the implementation conditions not specified are conventional conditions in the industry. The technical features involved in each embodiment of the present invention can be combined with each other as long as they do not conflict with each other.

[0054] Unless otherwise specified, the reagents involved in the following examples and comparative examples are all commercially available products, or can be prepared by referring to the existing technology.

[0055] Example 1

[0056] 0.4694 g of [1,1':4',1"-terphenyl]-4,4"-dicarboxylic acid (CAS: 13653-84-4), 0.1978 g of 9-oxo-9H-fluorene-2,7-dicarboxylic acid (CAS: 792-26-7), 1.3328 g of 4,4'-biphenyl ether dicarboxylic acid (CAS: 2215-89-6, the molar ratio of the three is 2:1:7) and 1.0073 g of hydrazine sulfate (the molar ratio of the total amount of diacid to hydrazine sulfate is 1:1.05) are mixed, and the mixture is dissolved in 20% fuming sulfuric acid (the mass fraction of SO3 is 20%), heated to 75°C and stirred to dissolve, then heated to 120°C for copolymerization, and after reacting for 4 hours, 0.1 g of aminoterephthalic acid is added to cap the end groups so as to graft the amino active end groups. Then the product is poured into deionized water for washing, and alkali solution is added for soaking to neutralize the residual sulfuric acid in the polymer, and finally washed to neutrality and dried.

[0057] 0.5 g of the dried product was dissolved in an organic solvent, nitrogen-methyl pyrrolidone, to prepare a solution with a mass concentration of 4%, 1 g of maleic anhydride, 0.1 g of cobalt acetate, and 5 mL of acetic anhydride were added, and the temperature was raised to 50° C. for reaction for 5 h to obtain a functionalized fluorescent material.

[0058] Figure 1 This is a schematic diagram of the reaction process of the fluorescent material in Example 1. It is only for showing the reaction process and does not mean that the fluorescent material is only the structure shown in the figure. Figure 2 is the fluorescence emission spectrum of the fluorescent material prepared in Example 1 under 405 nm excitation, Figure 3 This is a real-object image of the fluorescent material prepared in Example 1 under 405nm excitation. It can be seen that the fluorescent material has a fluorescence emission wavelength of 500nm under the blue 405nm wavelength, a significant fluorescence emission spectrum peak appears, and the fluorescence intensity is high.

[0059] Comparative Example 1

[0060] The difference between this comparative example and Example 1 is that:

[0061] The molar ratio of [1,1':4',1"-terphenyl]-4,4"-dicarboxylic acid, 9-oxo-9H-fluorene-2,7-dicarboxylic acid, and 4,4'-biphenyl ether dicarboxylic acid is 4:1:5.

[0062] During functional grafting, it was found that the polymer was difficult to dissolve in organic solvents such as nitrogen-methyl pyrrolidone, making processing difficult. It was speculated that this was because the amount of 4,4'-biphenyl ether dicarboxylic acid was too low, resulting in poor polarity of the polymer molecules.

[0063] Comparative Example 2

[0064] The difference between this comparative example and Example 1 is that the type and amount of the diacid are different.

[0065] This comparative example did not use 9-oxo-9H-fluorene-2,7-dicarboxylic acid, and the molar ratio of [1,1′:4′,1″-terphenyl]-4,4″-dicarboxylic acid to 4,4′-biphenyl ether dicarboxylic acid was 3:7.

[0066] When testing the fluorescence spectrum, it was found that the fluorescence intensity of the fluorescent material was low and could not be used for fluorescent labeling.

[0067] Comparative Example 3

[0068] The difference between this comparative example and Example 1 is that the type and amount of the diacid are different.

[0069] This comparative example does not use [1,1':4',1"-terphenyl]-4,4"-dicarboxylic acid and 4,4'-biphenyl ether dicarboxylic acid, but only uses 9-oxo-9H-fluorene-2,7-dicarboxylic acid, and the molar ratio of 9-oxo-9H-fluorene-2,7-dicarboxylic acid to hydrazine sulfate is 1:1.05.

[0070] The UV absorption spectrum of the test product is as follows: Figure 4 As shown, the results show that its ultraviolet absorption wavelength is 366nm, which cannot meet the requirement of 405nm.

[0071] Comparative Example 4

[0072] 4,4'-biphenyl ether dicarboxylic acid, terephthalic acid, isophthalic acid, 4,4'-biphenyl dicarboxylic acid, [1,1':4',1"-terphenyl]-4,4"-dicarboxylic acid were mixed with hydrazine sulfate (the molar ratio of the total amount of diacid to hydrazine sulfate was 1:1.05), and the mixture was dissolved in 20% fuming sulfuric acid (the mass fraction of SO3 was 20%), heated to 75°C and stirred to dissolve it, then heated to 120°C for copolymerization, and after 4 hours of reaction, 0.1g of aminoterephthalic acid was added to cap the end to graft the amino active end group. Then the product was poured into deionized water for washing, and alkali solution was added to soak and neutralize the residual sulfuric acid in the polymer, and finally washed to neutral and dried. The products were named EPOD, PPOD, MPOD, BPOD and TPOD respectively.

[0073] The UV absorption spectrum of the product was tested. Figure 5 As shown, the results show that only TPOD can reach the requirement of 405nm ultraviolet absorption wavelength. This is because [1,1':4',1"-terphenyl]-4,4"-dicarboxylic acid has a terphenyl structure, the molecular conjugation degree formed is higher, and the absorption wavelength can be significantly red-shifted. However, further studies have found that TPOD is difficult to dissolve in organic solvents such as nitrogen-methyl pyrrolidone, and the fluorescence intensity is low, so it cannot be used for fluorescent labeling.

[0074] The above detailed description of the present invention is intended to enable persons familiar with the art to understand the contents of the present invention and implement them. It does not limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A fluorescent material, characterized in that: The fluorescent material has structural units shown in Formula I, Formula II and Formula III, The formula I is: The formula II is: The formula III is: Among them, R1, R2, R3, R4, R5, R6, R7, R8, R9, R 10 , R 11 , R 12 , R 13 , R 14 , R 15 , R 16 Each is independently selected from -H or -SO3H.

2. The fluorescent material according to claim 1, characterized in that The end groups of the fluorescent material are 3. The method for preparing the fluorescent material according to claim 1 or 2, characterized in that: The preparation method comprises reacting [1,1':4',1"-terphenyl]-4,4"-dicarboxylic acid, 9-oxo-9H-fluorene-2,7-dicarboxylic acid and 4,4'-biphenyl ether dicarboxylic acid with hydrazine sulfate in the presence of fuming sulfuric acid.

4. The method for preparing the fluorescent material according to claim 3, characterized in that: The molar ratio of [1,1':4',1"-terphenyl]-4,4"-dicarboxylic acid, 9-oxo-9H-fluorene-2,7-dicarboxylic acid and 4,4'-biphenyl ether dicarboxylic acid is controlled to be (1-3):1:(6-10).

5. The method for preparing the fluorescent material according to claim 3, characterized in that: The molar ratio of the total feed mole of [1,1':4',1"-terphenyl]-4,4"-dicarboxylic acid, 9-oxo-9H-fluorene-2,7-dicarboxylic acid and 4,4'-biphenyl ether dicarboxylic acid to the feed mole of hydrazine sulfate is 1:(1-1.5).

6. The method for preparing the fluorescent material according to claim 3, characterized in that: The [1,1':4',1"-terphenyl]-4,4"-dicarboxylic acid, 9-oxo-9H-fluorene-2,7-dicarboxylic acid, 4,4'-biphenyl ether dicarboxylic acid, hydrazine sulfate and fuming sulfuric acid are first dissolved at 60-90° C., and then reacted at 110-130° C. for 3-5 hours.

7. The method for preparing a fluorescent material according to any one of claims 3 to 6, characterized in that: The preparation method further comprises adding a capping agent to cap the reaction product after the reaction is completed, so as to graft amino groups onto the reaction product, and then reacting the grafted reaction product with maleic anhydride.

8. The method for preparing the fluorescent material according to claim 7, characterized in that: The end-capping agent is aminoterephthalic acid; and / or, The molar ratio of the end-capping agent to the total molar amount of the [1,1':4',1"-terphenyl]-4,4"-dicarboxylic acid, 9-oxo-9H-fluorene-2,7-dicarboxylic acid and 4,4'-biphenyl ether dicarboxylic acid is (0.01-0.1):1; and / or, The end-capping temperature is 110-130°C.

9. The method for preparing a fluorescent material according to claim 7, characterized in that: reacting the grafted reaction product with maleic anhydride in the presence of a cobalt catalyst and a dehydrating agent; and / or, The reaction temperature of the grafted reaction product and maleic anhydride is controlled to be 40-60° C.; and / or, The mass ratio of the grafted reaction product to maleic anhydride is controlled to be 1:(1-3).

10. Use of the fluorescent material according to claim 1 or 2 or the fluorescent material prepared by the preparation method according to any one of claims 3 to 9, characterized in that: The fluorescent material is applied to the fields of biomarker detection, cell imaging, drug delivery, in vitro diagnostic detection and biosensor.

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