Fluorescent polymer containing diphenyl ether-isatin-terphenyl copolymer, fluorescent hydrophilic composite membrane and application of fluorescent polymer and fluorescent hydrophilic composite membrane in amino acid fluorescent sensing detection
The fluorescent hydrophilic composite film prepared by indigin-diphenyl ether-terbenzene copolymerization fluorescent polymer and electrospinning technology solves the instrument dependence and complexity of the existing amino acid detection methods, and achieves low-cost and high-sensitivity amino acid detection.
Patent Information
- Application Number
- CN202510689884.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-27
- Publication Date
- 2025-08-15
AI Technical Summary
The existing amino acid detection methods require precise instruments and cumbersome sample preparation procedures, and lack high-sensitivity fluorescent probes.
The fluorescent hydrophilic composite film was prepared by electrospinning technology using inditin-diphenyl ether-terbenzene copolymerization fluorescent polymer, and the hydrophilicity of the film was optimized by TiO2 loading to achieve sensitive detection of amino acids.
The prepared fluorescent polymer has good thermal stability and luminous properties, and can easily and at low cost to realize qualitative or quantitative detection of multiple amino acids, improving the sensitivity and convenience of detection.
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Abstract
Description
Technical Field
[0001] The present invention belongs to the field of luminescent nanomaterials and optical sensing, and specifically relates to a diphenyl ether-isatin-terphenyl copolymer fluorescent polymer, a fluorescent hydrophilic composite membrane and its application in amino acid fluorescent sensing detection. Background Art
[0002] Amino acids, the fundamental building blocks of proteins, play a central role in maintaining cellular structure, facilitating nutrient transport and storage, and promoting tissue repair and regeneration, making them an essential component of all life forms. Furthermore, any abnormal changes in amino acid physiological levels are often manifested in common metabolic disorders, serious neurological diseases, and cardiovascular diseases. Consequently, amino acid detection methods have attracted widespread attention, and the development of methods for detecting trace amino acids has become highly important for their effective clinical diagnosis.
[0003] Traditional methods for amino acid detection include liquid chromatography-mass spectrometry, gas chromatography-mass spectrometry, and capillary electrophoresis. However, these methods typically require sophisticated instrumentation, tedious sample preparation, and experienced instrument operators. Compared to the first three methods, fluorescent sensors are favored by researchers due to their effectiveness, convenience, and high sensitivity. However, the variety of fluorescent probes suitable for amino acid sensing is relatively limited, and further research is needed. Summary of the Invention
[0004] The purpose of the present invention is to solve the above problems and provide a fluorescent polymer and a preparation method thereof. The fluorescent polymer has good thermal stability and luminescence performance, has good application prospects, and fiberizing the polymer is beneficial to the convenience of its application.
[0005] Another object of the present invention is to provide a fluorescent nanofiber membrane with hydrophilic properties prepared from the above fluorescent polymer. The fiber membrane can be used for the detection of multiple amino acids. According to the changes in the luminescence of the detection membrane, amino acid recognition and detection can be achieved sensitively and simply.
[0006] In order to achieve the above object, the present invention is implemented through the following technical solutions:
[0007] An indigo-diphenyl ether fluorescent polymer, the structural formula of which is:
[0008]
[0009] The synthetic route of the above-mentioned indigo-diphenyl ether fluorescent polymer is as follows:
[0010]
[0011] In the structural formula, the number of the repeating structural unit n is 150-200.
[0012] The preparation method of the fluorescent polymer comprises the following steps:
[0013] Isatin and diphenyl ether are mixed in an organic solvent, a catalyst is added, and the mixture is stirred in an ice bath for 30 to 45 minutes. The resulting polymer solution is placed in 100°C hot water for phase separation, and washed 4 to 6 times with anhydrous ethanol to obtain the target polymer. The polymer is then post-dried in a vacuum drying oven at 140 to 160°C for 20 to 28 hours to obtain the final product.
[0014] More preferably, the vacuum drying temperature is 150° C. and the drying time is 24 hours.
[0015] The molar ratio of diphenyl ether to indigo carmine is 7:12 to 10:12.
[0016] The fluorescent polymer structure of diphenyl ether-isatin-terphenyl copolymer is:
[0017]
[0018] Wherein x=70%-90%, y=10%-30%.
[0019] The synthetic route of the above-mentioned diphenyl ether-isatin-terphenyl copolymer fluorescent polymer is as follows:
[0020]
[0021] Preferably, the preparation method of the terphenyl-isatin-diphenyl ether copolymer comprises the following steps:
[0022] Isatin monomer, diphenyl ether, and terphenyl are added to an organic solvent at a specific molar ratio, a catalyst is slowly added dropwise, and magnetic stirring is performed in an ice bath for 2-3 hours. The resulting polymer solution is placed in 100°C hot water for phase separation, and washed 4-6 times with anhydrous ethanol to obtain the target polymer. This polymer is then post-dried in a vacuum drying oven at 140-160°C for 20-28 hours to obtain the final product.
[0023] More preferably, the vacuum drying temperature is 150° C. and the drying time is 24 hours.
[0024] Preferably, the molar ratio of diphenyl ether to isatin is 7:12 to 10:12. The molar ratio of diphenyl ether to terphenyl is 9:1 to 7:3. More preferably, the molar ratio of diphenyl ether to terphenyl to isatin is 8:2:12. This molar ratio yields the best performing polymer, which can improve sensor sensitivity in amino acid detection.
[0025] Preferably, the organic solvent is dichloromethane, and the catalyst is trifluoromethanesulfonic acid, wherein the mass ratio of trifluoromethanesulfonic acid to isatin is 3 to 4:1.
[0026] A method for preparing a nanofiber membrane from a terphenyl-isatin-diphenyl ether copolymer: the luminescent polymer is stirred at a constant temperature to completely dissolve it in an organic solvent, and the obtained stock solution is subjected to an electrostatic spinning process to prepare a nanofiber membrane.
[0027] Preferably, the organic solvent is one of N,N-dimethylacetamide, dichloromethane, and dimethyl sulfoxide. Spinning solution preparation conditions include a temperature of 25-50°C and a concentration of 8-15% by weight. Static spinning process control conditions include a positive spinning voltage of 12-18 kV, a negative spinning voltage of -1-5 kV, and a spinning solution flow rate of 0.05-0.25 mL / h.
[0028] A fluorescent hydrophilic composite membrane is provided. Based on the above polymer, the present invention provides a conjugated polymer membrane with modified wettability for the detection of liquid amino acids.
[0029] TiO2 is dispersed in anhydrous ethanol to obtain an electrospray solution, and fluorescent polymer spinning solution and TiO2 electrospray solution are used to simultaneously perform electrostatic spinning and electrostatic spraying, respectively, to evenly anchor TiO2 powder on the fiber surface to obtain a fluorescent hydrophilic fiber membrane; the mass ratio of TiO2 to the luminescent polymer is 1:20 to 3:25.
[0030] The flow rate of the spray solution was 0.05-0.25 mL / h. Other parameters of the propulsion spray were consistent with the spinning parameters of the electrospun membrane.
[0031] Compared with other loading methods, the electrospray loading method can load the load onto the target membrane in a nanoscale structure, and can retain the performance of the original membrane as much as possible on the basis of completing specific performance modification. In addition, it also has the advantages of simple operation and low cost.
[0032] The fluorescent hydrophilic composite membrane prepared by the present invention is used in amino acid fluorescence sensing detection to achieve qualitative or quantitative detection of amino acids.
[0033] The amino acid is one or more of tyrosine, leucine, phenylalanine, valine, isoleucine, and tryptophan.
[0034] Compared with the prior art, the present invention has the following beneficial effects:
[0035] (1) The fluorescent polymer synthesized by the present invention introduces an indigo monomer into the polymer structure, which can improve the photostability and application possibility of the polymer, and is beneficial to the improvement of the fluorescence response in amino acid sensing, so that it has better amino acid responsiveness. The addition of terphenyl not only improves thermal stability, but also enhances the fluorescence intensity due to its rich conjugated structure, thereby better observing the effect of polymer sensing, increasing visibility, and having a synergistic promotion effect.
[0036] (2) The amino acid sensing hydrophilic membrane prepared by the fluorescent polymer of the present invention has the advantages of low cost, simple operation and high efficiency. According to the changes in the luminescence of the detection membrane, amino acid recognition can be realized sensitively and simply. BRIEF DESCRIPTION OF THE DRAWINGS
[0037] Figure 1 The following are the H NMR spectra and IR absorption spectra of the polymers in Examples 1 and 2;
[0038] Figure 2 This is a partial magnified NMR image of terphenyl-III;
[0039] Figure 3 is a microscopic morphology of the polymer film in Example 3;
[0040] Figure 4 This is a physical picture of the fiber membrane described in Example 3 under ultraviolet irradiation;
[0041] Figure 5 The microscopic morphology and contact angle test comparison diagram of the functionalized membrane in Example 4;
[0042] Figure 6 The fluorescence spectrum of amino acid sensing in Example 5 and the actual image under ultraviolet light;
[0043] Figure 7 (a) is a graph showing the change of fluorescence intensity with tyrosine concentration, and (b) is a graph showing the linearity of tyrosine fluorescence detection. Figure 7 (c) is the graph showing the change of fluorescence intensity with tryptophan concentration. Figure 7 (d) is a linear detection graph of tryptophan fluorescence detection;
[0044] Figure 8 Quickly scan fluorescence results for colorimetric software. DETAILED DESCRIPTION
[0045] The preferred embodiments of the present invention will be described in more detail below with reference to the accompanying drawings and specific examples.
[0046] The monomers used in the following examples are all commercially available, among which diphenyl ether and indigo were purchased from Shangsheng Chemical Technology Co., Ltd., and terphenyl was purchased from Aladdin Biochemical Technology Co., Ltd.
[0047] Example 1
[0048] Indigo-diphenyl ether fluorescent copolymer, its structural formula is as follows:
[0049]
[0050] The synthetic route of the above fluorescent polymer is as follows:
[0051]
[0052] The preparation method of the above-mentioned indigo copolymer is as follows:
[0053] Using a three-necked flask as the reaction vessel, 6 mL of dichloromethane was added as the reaction solvent, 5.5 mL of trifluoromethanesulfonic acid was added as the catalyst, and 12 mmol of indigo carmine monomer and 10 mmol of diphenyl ether were added for a condensation reaction to successfully prepare BI polymer. During the experiment, the reaction system was magnetically stirred in an ice bath for 40 minutes until complete dissolution. The homogeneous solution was then injected into 400 mL of hot water for phase separation. The target polymer was obtained after four washes with 300 mL of anhydrous ethanol. The final product was post-dried in a vacuum drying oven at 150°C for 24 hours. The yield was 97%.
[0054] Figure 1 The H-NMR spectrum and IR absorption spectrum of the polymer of Example 1 show that the integral values of the absorption peaks of the synthesized polymer are consistent with the number of protons in the designed structural formula, and the functional group region can also achieve a one-to-one correspondence with its structural formula.
[0055] Example 2
[0056] Terphenyl-Indigo-Diphenyl Ether Fluorescent Copolymer, its structural formula is as follows:
[0057]
[0058] The synthetic route of the above fluorescent polymer is as follows:
[0059]
[0060] The preparation method of the fluorescent polymer is as follows:
[0061] 1. Terphenyl-I fluorescent polymer: 1 mmol of terphenyl, 12 mmol of isatin, and 6 mL of dichloromethane were added to a three-necked flask in an ice bath. After stirring until the solids were completely dissolved, 9 mmol of diphenyl ether and 5.5 mL of trifluoromethanesulfonic acid were added as catalysts. The mixture was polymerized for 1 hour under continuous stirring. Subsequently, the reaction solution was poured into 400 mL of hot water for phase separation. The residual monomers and catalyst were removed by washing three times with 400 mL of anhydrous ethanol. The final product was dried in a vacuum oven at 150°C for 24 hours with a yield of 97%.
[0062] 2. Terphenyl-II fluorescent polymer:
[0063] Terphenyl-II fluorescent polymer differs from terphenyl-I in that the molar amount of terphenyl is increased to 2 mmol, and 8 mmol of diphenyl ether is added. The remaining steps are the same as for terphenyl-I. The mixture is polymerized for 1.5 hours under continuous stirring. Subsequently, the phase separation, washing, and drying steps are similar to those for terphenyl-I, resulting in a 98% yield for terphenyl-II fluorescent polymer.
[0064] 3. Terphenyl-III fluorescent polymer:
[0065] Compared to the terphenyl-I fluorescent polymer, the terphenyl-III fluorescent polymer differs in that the molar amount of terphenyl is increased to 3 mmol, and 7 mmol of diphenyl ether is added. The remaining steps are the same as for terphenyl-I. The mixture is polymerized for 2 hours under continuous stirring. Subsequently, the phase separation, washing, and drying steps are similar to those for terphenyl-I, resulting in a 98% yield for the terphenyl-III fluorescent polymer.
[0066] Figure 1 The H-NMR spectrum and IR absorption spectrum of the polymer in Example 2 show that the integral values of the absorption peaks of the synthesized polymer are consistent with the number of protons in the designed structural formula, and the functional group region can also achieve a one-to-one correspondence with its structural formula. Figure 2 This is a partial magnified NMR image of terphenyl-III.
[0067] Example 3
[0068] Preparation of fluorescent polymer electrospinning membrane, the operation steps are as follows:
[0069] The isatin copolymer prepared in Example 1 and the terphenyl-I, terphenyl-II, and terphenyl-III polymers prepared in Example 2 were dissolved in N,N-dimethylacetamide solvent to prepare a 10% spinning solution. A needle-type syringe was used to load the spinning solution. A 14kV high-voltage electric field was applied to the needle, and a negative voltage of -3kV was applied to the receiving device. The solution was pumped at a constant flow rate of 0.2mL / h using a microsyringe pump. Fiber membranes were collected at room temperature.
[0070] Figure 3 Figure 2 is the microscopic morphology of each polymer film. When the mass concentration of the spinning solution is 10%, the four fibers all show good microstructure, and the only difference is the average fiber diameter. This proves that the four fibers have certain fiber-forming ability.
[0071] Figure 4 (a) is a real picture of the fiber membrane described in Example 3 under ultraviolet irradiation. Figure 4 As can be seen in (a), the fluorescence intensity of the indigo copolymer is the lowest, followed by terphenyl-I. Macroscopically, the membrane fibers are relatively loose and dispersed. Terphenyl-II and terphenyl-III exhibit similar fluorescence and macroscopic appearances. Terphenyl-II exhibits the strongest luminescence and better thermal stability, and the resulting fibers are uniform in diameter and well-dispersed.
[0072] It is particularly important that the indigo copolymer fluorescent film itself has good fluorescence. The addition of terphenyl can effectively enhance the fluorescence of the polymer and its fiber-forming ability, but the large steric hindrance of the structure will affect the sensing effect and the fiber-forming effect of high-concentration solutions. Therefore, terphenyl-II fiber membrane is preferred.
[0073] Figure 4 (b) is the thermogravimetric data of the four polymers. The samples exhibit good luminescence properties and thermal stability, and mainly exhibit yellow-green fluorescence under ultraviolet light. Figure 4 (b) It shows that the polymer has a high thermal decomposition temperature, the thermal decomposition is stable above 400°C, and the residual carbon rate is as high as over 53%.
[0074] Example 4
[0075] A method for preparing a fluorescent hydrophilic nanofilm based on terphenyl-II conditions is as follows:
[0076] The terphenyl-II polymer prepared in Example 2 was dissolved in N,N-dimethylacetamide solvent to prepare a spinning solution with a mass fraction of 10%.
[0077] Through synchronous electrostatic spraying technology, hydrophilic TiO2 was dispersed in anhydrous ethanol with a concentration ratio of 3 mg / 7 mL. The mass ratio of TiO2 to spinning solute was 3:25. The hydrophilic material was also loaded using a needle-type syringe, and its spraying flow rate was adjusted to 0.2 mL / h.
[0078] Figure 5 (a) is the microscopic morphology of the functionalized membrane and the contact angle test comparison diagram, Figure 5 (b) Fluorescence emission spectra of electrospun membranes after loading with different concentrations of TiO2. Figure 5(a) illustrates the uniformity of the loading. In addition, since the hydrophilic TiO2 is distributed on the surface of the membrane, the polymer membrane also achieves a transition from hydrophobic (127°) to hydrophilic (64°) after modification. Figure 5 (b) The fluorescence effect of TiO2 on the polymer film is shown. Due to the loading of particles, the light absorption capacity of the polymer is affected, thus showing a fluorescence quenching effect. The greater the amount of TiO2, the more obvious the effect on the luminescence of the polymer film.
[0079] The wettability of the fiber membrane can only be guaranteed when the hydrophilic TiO2 reaches a certain loading amount. Excessive TiO2 will cover the membrane surface in large quantities and affect the surface structure of the fiber membrane, thereby affecting the luminescence effect of the nanomembrane. The preferred loading amount is 12%.
[0080] Example 5
[0081] The application of amino acid sensing fluorescent film, the sensing process is as follows:
[0082] The fluorescent hydrophilic fiber membrane described in Example 4 was cut into a size of 1.5 cm × 5 cm and immersed in branched-chain amino acid and aliphatic amino acid solutions with a concentration of 0.03 mg / mL, specifically tyrosine, leucine, phenylalanine, valine, isoleucine, and tryptophan. After soaking for 10 minutes, it was taken out and dried to observe the change in fluorescence intensity.
[0083] like Figure 6 As shown in the figure, compared with the membrane that does not participate in sensing, the peak position of the maximum fluorescence emission peak (about 360nm) has no significant change, but the peak intensity changes significantly. Among them, tyrosine shows fluorescence enhancement, while tryptophan shows obvious fluorescence quenching due to the π-π* stacking effect. The sensing photos of other amino acids are also easy to distinguish. This shows that the hydrophilic fluorescent polymer membrane prepared by the present invention can be used for sensing and detecting a variety of amino acids. According to the changes in the luminescence of the detection membrane, amino acid recognition can be achieved sensitively and simply. Figure 8 This study uses colorimetric software to quickly scan fluorescence results and conduct qualitative color analysis based on RGB values. The sensor membrane of the present invention primarily performs qualitative analysis, making it easier to distinguish amino acids with the largest fluorescence changes. Other amino acid analytes can also be detected using colorimetric software, and these other analytes have distinct crystal forms on the sensor, making them distinguishable.
[0084] Tyrosine and tryptophan, which exhibit the greatest fluorescence changes in the amino acid sensing fluorescent membrane, were tested for quantitative detection at different concentrations. The concentrations of the amino acid solutions were set at 0.02 mg / mL, 0.04 mg / mL, 0.06 mg / mL, 0.08 mg / mL, and 0.10 mg / mL, respectively. The limits of detection (LODs) for the two targets were calculated based on the peak fluorescence intensity.
[0085] Figure 7 (a) is the graph showing the change of fluorescence intensity with tyrosine concentration. Figure 7 (b) is the linear detection graph of tyrosine fluorescence detection. According to the slope and standard deviation, the LOD of tyrosine can be calculated to be 0.015 mg / mL. Figure 7 (c) is the graph showing the change of fluorescence intensity with tryptophan concentration. Figure 7 (d) is the linear detection graph of tryptophan fluorescence detection, and its LOD value is 0.013 mg / mL.
[0086] While various embodiments of the present invention have been described above, the foregoing description is intended to be illustrative and non-exhaustive, and is not intended to be limiting of the disclosed embodiments. Numerous modifications and variations will be apparent to those skilled in the art without departing from the scope and technical principles of the described embodiments, and such modifications and variations should be considered within the scope of the present invention.
Claims
1. A diphenyl ether-isatin-terphenyl copolymer fluorescent polymer, characterized in that: The fluorescent polymer has the following structural formula: In the above structure: x = 70% - 90%, y = 10% - 30%.
2. The method for synthesizing the diphenyl ether-isatin-terphenyl copolymer fluorescent polymer according to claim 1, wherein: The following steps are involved: Isatin, diphenyl ether and terphenyl are added to an organic solvent, a catalyst is added, and the mixture is stirred in an ice bath for reaction; the target product is obtained through phase separation, washing and drying.
3. The method for synthesizing the diphenyl ether-isatin-terphenyl copolymer fluorescent polymer according to claim 2, wherein: The molar ratio of diphenyl ether to isatin is 7:12 to 10:12; the molar ratio of diphenyl ether to terphenyl is 9:1 to 7:3; the organic solvent is dichloromethane; and the catalyst is trifluoromethanesulfonic acid.
4. The method for synthesizing the diphenyl ether-isatin-terphenyl copolymer fluorescent polymer according to claim 2, wherein: The molar ratio of diphenyl ether, terphenyl and indigo is 8:2:
12.
5. A fluorescent electrospun fiber membrane, characterized in that: The fluorescent polymer according to claim 1 is used to prepare a nanofiber membrane according to an electrospinning process; the preparation method comprises the following steps: The fluorescent polymer is completely dissolved in an organic solvent, and the obtained spinning solution is subjected to electrostatic spinning to obtain a fluorescent electrospun fiber membrane.
6. The fluorescent electrospun fiber membrane according to claim 5, characterized in that: The organic solvent is one of N,N-dimethylacetamide, dichloromethane and dimethyl sulfoxide.
7. The fluorescent electrospun fiber membrane according to claim 5, characterized in that: Spinning solution preparation conditions: temperature of 25-50°C, concentration of 8wt%-15wt%; electrospinning process conditions: spinning positive voltage of 12kV-18kV, negative voltage of -1-5kV, spinning solution flow rate of 0.05-0.25mL / h.
8. A fluorescent hydrophilic composite membrane, characterized in that: TiO2 is loaded on the electrospun membrane according to claim 5 by electrostatic spraying, and the preparation method comprises the following steps: TiO2 is dispersed in anhydrous ethanol to obtain a TiO2 electrospray solution, and the fluorescent polymer spinning solution according to claim 1 and the TiO2 electrospray solution are used simultaneously for electrostatic spinning and electrostatic spraying, respectively, to uniformly anchor the TiO2 powder on the fiber surface to obtain a fluorescent hydrophilic fiber membrane; the mass ratio of TiO2 to the fluorescent polymer is 1:20 to 3:25, and the flow rate of the spray solution is 0.05 to 0.25 mL / h.
9. An application of the fluorescent hydrophilic composite membrane according to claim 8, characterized in that: Application in amino acid fluorescence sensing.
10. The use according to claim 9, characterized in that: The amino acid is one or more of tyrosine, leucine, phenylalanine, valine, isoleucine, and tryptophan.