Preparation and application of pH and polarity dual-responsive fluorescent probe with aggregation-induced emission characteristics

Abstract

The application belongs to the technical field of fluorescent probe, and particularly relates to a preparation method and property research of a pH and polarity double-response fluorescent probe with an aggregation-induced effect. The preparation method of the fluorescent probe is simple, the product yield is high, and the method is suitable for scale popularization and use. The probe (E) -3 - (2 - hydroxyethyl) -1, 1 - dimethyl -2 - (2 - (5 - (4 - (1, 2, 2 - triphenylvinyl) phenyl) thiophene -2 - yl) ethenyl) -1H - benzo [e] indol -3 - onium iodide (HDTVB) has the strongest fluorescence intensity under basic conditions when excited at 370 nanometers, and the fluorescence intensity gradually weakens with the increase of the solution acidity; the fluorescence intensity is the strongest under acidic conditions when excited at 540 nanometers, and the fluorescence intensity gradually weakens with the increase of the solution basicity. The probe can detect the pH range of 3 - 11, has a good linear ratio relationship, and can be cyclically tested. The probe also has a strong fluorescence response to polarity, and the fluorescence emission intensity gradually increases with the decrease of the polarity.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of fluorescent probes, and particularly relates to a preparation method and application of a pH and polarity dual-response fluorescent probe with an aggregation-induced property. BACKGROUND

[0002] Polarity is an important parameter in the microenvironment of the human body, and immune response, cell activation and differentiation can all lead to changes in cell polarity. Abnormal changes in the microenvironment of organisms are closely related to some diseases, and therefore have attracted widespread attention. Abnormal changes in polarity can cause many diseases, such as diabetes, Alzheimer's disease, cancer and the like.

[0003] As an important indicator of acidity, pH value is one of the most important parameters in chemical industry, biotechnology and environmental science. In biological processes, the pH value in cells is a key factor for maintaining the homeostasis of the intracellular environment and the normal functioning of various organelles. Most of the currently reported pH fluorescent sensors are based on a single emission band, which are easily disturbed by environmental conditions and background fluorescence signals. Ratio fluorescence provides self-calibration through dual-channel detection, which can minimize the disturbance of the environment and instruments on accurate pH detection. Therefore, it is important to design and synthesize a ratio fluorescent probe for pH detection.

[0004] Fluorescence imaging has attracted widespread attention due to its simple synthetic operation, high sensitivity, non-invasiveness and low toxicity. The fluorescence of the probe is easily quenched due to photobleaching. However, fluorescent probes with aggregation-induced emission characteristics can overcome this defect and are suitable for non-invasive detection of microenvironment changes. Although there are a wide variety of fluorescent probes, some of them have the shortcomings of short fluorescence emission wavelength, inability to reach the near-infrared region, weak tissue penetration ability leading to incomplete collection of fluorescence signals, background interference and the like. In summary, it is necessary to develop a near-infrared fluorescent probe with aggregation-induced emission characteristics for the detection of pH and polarity. SUMMARY

[0005] The application aims to provide a preparation method and property research of a pH and polarity dual-response fluorescent probe with an aggregation-induced property. HDTVB has the characteristics of simple synthetic route, good selectivity, high sensitivity and large Stokes shift, and can effectively detect pH and polarity under physiological conditions.

[0006] The fluorescent probe (E)-3-(2-hydroxyethyl)-1,1-dimethyl-2-(2-(5-(4-(1,2,2-triphenylvinyl) phenyl)thiophene-2-yl)vinyl)-1H-benzo[e]indol-3-ium iodide (HDTVB) in the application has the following molecular structure:

[0007]

[0008] The synthesis process of the fluorescent probe in the present application is as follows:

[0009]

[0010] A1: 3-(2-hydroxyethyl)-1,1,2-trimethyl-1H-benzo[e]indol-3-ium iodide

[0011] A2: 5-(4-(1,2,2-triphenylvinyl)phenyl)thiophene-2-carboxaldehyde

[0012] HDTVB: (E)-3-(2-hydroxyethyl)-1,1-dimethyl-2-(2-(5-(4-(1,2,2-triphenylvinyl)phenyl)thiophen-2-yl)vinyl)-1H-benzo[e]indol-3-ium sulfonate

[0013] The preparation steps of the probe HDTVB are as follows:

[0014] 2-iodoethanol is measured into a single-neck round-bottom flask containing 1,1,2-trimethyl-1H-benzo[e]indole and toluene, ultrasonic dissolution is performed, vacuum is applied, and heating reflux is performed for about 2 hours. After the reaction is completed, cooling is performed to room temperature, a precipitate is generated, suction filtration is performed, and washing is performed with chloroform, and drying is performed in a vacuum drying box to obtain 3-(2-hydroxyethyl)-1,1,2-trimethyl-1H-benzo[e]indol-3-ium iodide (A1, yield 72.2%).

[0015] 1-(4-bromophenyl)-1,2,2-triphenylstyrene and 5-formyl-2-thiopheneboronic acid are weighed, and ultrasonic dissolution is performed in a tetrahydrofuran (THF) solution. Potassium carbonate aqueous solution and tetrakis(triphenylphosphine)palladium are sequentially added, ultrasonic dissolution is performed, vacuum is applied, and heating reflux is performed for about 24 hours. After the reaction is completed, the reaction liquid is cooled to room temperature and spin-dried to obtain a crude product, which is separated and purified by column chromatography, and dried to obtain 5-(4-(1,2,2-triphenylvinyl)phenyl)thiophene-2-carboxaldehyde (A2, yield 23.4%).

[0016] A1 is added to a round-bottom flask containing anhydrous ethanol, heating reflux is performed at 55°C until A1 is dissolved. A2 is accurately weighed and added to the reaction system, and is completely dissolved, and heating reflux is performed for 48 hours. At the end of the reaction, the reaction solution is cooled to room temperature, a large amount of precipitate is precipitated and suction filtered and washed, and is placed in a vacuum drying box to dry, to obtain (E)-3-(2-hydroxyethyl)-1,1-dimethyl-2-(2-(5-(4-(1,2,2-triphenylvinyl)phenyl)thiophen-2-yl)vinyl)-1H-benzo[e]indol-3-ium iodide (HDTVB, yield 62.8%).

[0017] The detection mechanism of the fluorescent probe of the present application is as follows:

[0018]

[0019] The introduction of a thienyl derivative into a positively charged benzindole skeleton and the connection through a C=C bond enable the fluorescent molecule HDTVB to exhibit solvatochromism and high sensitivity to changes in polarity. In addition, the introduction of a hydroxyl group as a pH response site in the probe enables the switching ring change in the structure of the probe molecule. Based on the above functions, a new type of polar and pH dual-responsive deep red fluorescent probe is designed and synthesized to reflect changes in polarity and pH in different solutions.

[0020] Figure 3 is the UV-Vis absorption spectrum of the probe HDTVB (1×10 -5 mol / L) in different solvents. The UV absorption spectrum of the probe in different solvents has obvious difference.

[0021] Figure 4 is the fluorescence emission spectrum of the probe HDTVB (1×10 -5 mol / L) in different solvents under an excitation wavelength of 370 nanometers.

[0022] Figure 5 is the fluorescence emission spectrum of the probe HDTVB (1×10 -5 mol / L) in different solvents under an excitation wavelength of 540 nanometers.

[0023] Figure 6 is the UV-Vis absorption spectrum of the probe HDTVB (1×10 -5 mol / L, 1 mM cetyltrimethylammonium bromide) in mixed solvents of dimethyl sulfoxide and toluene in different proportions.

[0024] Figure 7 is the fluorescence emission spectrum of the probe HDTVB (1×10 -5 mol / L, 1 mM cetyltrimethylammonium bromide) in mixed solvents of dimethyl sulfoxide and toluene under an excitation wavelength of 350 nanometers.

[0025] Figure 8 is the fluorescence emission spectrum of the probe HDTVB (1×10 -5 mol / L, 1 mM cetyltrimethylammonium bromide) in mixed solvents of dimethyl sulfoxide and toluene under an excitation wavelength of 520 nanometers.

[0026] Figure 9 is the fluorescence emission spectrum of the probe HDTVB (1×10 -5Photographs taken under sunlight and a handheld UV lamp with toluene concentration (mol / L, 1mM hexadecyltrimethylammonium bromide) as the toluene content gradually increased. The solution color showed a regular change visible to the naked eye, and the fluorescence intensity increased with increasing toluene content.

[0027] Figure 10 It is a probe HDTVB (1×10) -5 Images of the probe (mol / L, 1mM hexadecyltrimethylammonium bromide) under sunlight, laser pointer, and handheld UV light in pure dimethyl sulfoxide and in two different solvents: 1% dimethyl sulfoxide and 99% toluene. The images show that the probe exhibits a significant aggregation effect in the 1% dimethyl sulfoxide and 99% toluene systems, resulting in the Tyndall effect.

[0028] Figure 11 It is a probe HDTVB (1×10) -5 The image (A) and particle size analysis diagram (B) show the probe in a system of 1% dimethyl sulfoxide and 99% toluene (mol / L). It can be seen that the probe exhibits significant aggregation and relatively large particle size in this system.

[0029] Figure 12 It is a probe HDTVB (1×10) -5 The UV-Vis absorption spectra of the probe HDTVB (mol / L, 1mM hexadecyltrimethylammonium bromide) in PBS buffer solutions at different pH values ​​were obtained. The UV spectrum of the probe HDTVB showed a regular change with pH variation.

[0030] Figure 13 It is a probe HDTVB (1×10) -5 Fluorescence emission spectra of PBS buffer solutions at different pH values ​​(mol / L, 1mM hexadecyltrimethylammonium bromide) at an excitation wavelength of 370 nm. The fluorescence intensity gradually increases with increasing pH.

[0031] Figure 14 It is a probe HDTVB (1×10) -5 Fluorescence emission spectra of PBS buffer solutions at different pH values ​​(mol / L, 1mM hexadecyltrimethylammonium bromide) at an excitation wavelength of 540 nm. The fluorescence intensity gradually decreases with increasing pH.

[0032] Figure 15 It is a probe HDTVB (1×10) -5 The ratio of maximum emission fluorescence intensity I of mol / L, 1mM hexadecyltrimethylammonium bromide under two excitations 480 / I 650 Graph showing changes with pH.

[0033] Figure 16 It is a probe HDTVB (1×10) -5Linear relationship of probe HDTVB (1 x 10 480 / I 650 Linear relationship of probe HDTVB (1 x 10

[0034] Figure 17 Linear relationship of probe HDTVB (1 x 10 -5 Anti-interference of probe HDTVB (1 x 10

[0035] Figure 18 Anti-interference of probe HDTVB (1 x 10 -5 Anti-interference of probe HDTVB (1 x 10

[0036] Figure 19 Anti-interference of probe HDTVB (1 x 10 -5 Anti-interference of probe HDTVB (1 x 10 + + 2+ 2+ 3+ 2+ 2+ 2+ 2+ 2+ 3+ 2 + 2+ 2+ 2+ Anti-interference of probe HDTVB (1 x 10

[0037] Figure 20 Anti-interference of probe HDTVB (1 x 10 -5 Anti-interference of probe HDTVB (1 x 10 - - - ​​​​​​​​​​​​​​​​, CO3 2- , HCO3 - , PO4 3- , H2PO4 - , SO4 2- , Cl - , NO2 - , NO3 - , BF4 - , C2O4 2- , SCN - , S2O8 2- , CrO4 2- , ClO - , P2O7 4- , Cr2O7 2- , S 2- , HS - . All of the interferents have no effect on the fluorescence intensity of HDTVB, which indicates that the probe HDTVB has good anti-interference ability to biological small molecules.

[0038] Figure 21 is the stability study of the probe HDTVB (1 × 10 -5 mol / L, 1 mM cetyl trimethyl ammonium bromide) in PBS buffer solution with pH = 5. Within 1 hour, the fluorescence intensity of the probe at different temperatures has no great change, which indicates that the probe HDTVB has good stability in PBS buffer solution with pH = 5.

[0039] Figure 22 is the stability study of the probe HDTVB (1 × 10 -5 mol / L, 1 mM cetyl trimethyl ammonium bromide) in PBS buffer solution with pH = 7. Within 1 hour, the fluorescence intensity of the probe at different temperatures has no great change, which indicates that the probe HDTVB has good stability in PBS buffer solution with pH = 7.

[0040] Figure 23 is the stability study of the probe HDTVB (1 × 10 -5 mol / L, 1 mM cetyl trimethyl ammonium bromide) in PBS buffer solution with pH = 9. Within 1 hour, the fluorescence intensity of the probe at different temperatures has no great change, which indicates that the probe HDTVB has good stability in PBS buffer solution with pH = 9.

[0041] Figure 24 successively shows the optical physical properties of the prepared probe HDTVB (1 × 10 -5 mol / L) in different solvents, including the maximum absorption peak λ abs,max , the maximum emission λ em,max, Stokes shift and fluorescence quantum yield Φ (with quinine sulfate as reference).

[0042] Figure 25 The photophysical properties of the prepared probe HDTVB (1 x 10 -5 mol / L) in different solvents, including the maximum absorption peak λ abs,max , maximum emission λ em,max , Stokes shift and fluorescence quantum yield Φ (with rhodamine B as reference).

[0043] In summary, using simple organic synthesis methods, we obtained a pH and polarity dual-responsive fluorescent probe (E)-3-(2-hydroxyethyl)-1,1-dimethyl-2-(2-(5-(4-(1,2,2-triphenylvinyl) phenyl) thiophene-2-yl) ethenyl)-1H-benzo[e] indol-3-ium iodide (HDTVB). The probe has a clear solvatochromic phenomenon in different solvents, which can be observed with the naked eye, indicating that the probe exhibits different optical properties in solvents with different polarities. Secondly, with the increase of toluene solvent, the fluorescence intensity of the probe at different wavelengths is enhanced, which is due to the aggregation of the probe in the solvent, leading to the generation of aggregation-induced phenomenon due to the restriction of intramolecular torsion. Particle size distribution and Tyndall effect also verify this phenomenon. The probe has obvious regular changes in UV absorption spectrum and fluorescence emission spectrum in different pH buffer solutions, providing a good tool for detecting pH fluctuations. The preparation of this fluorescent probe fills the gap in the field of fluorescent probes that can simultaneously quantitatively detect pH and polarity, and the aggregation-induced characteristics of the probe make it exhibit excellent optical properties, with a large Stokes shift, which can be repeatedly used in the response process of pH. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 Preparation and design route of the probe (E)-3-(2-hydroxyethyl)-1,1-dimethyl-2-(2-(5-(4-(1,2,2-triphenylvinyl) phenyl) thiophene-2-yl) ethenyl)-1H-benzo[e] indol-3-ium iodide (HDTVB).

[0045] Figure 2 Mechanism of the probe HDTVB detecting solution polarity and pH response.

[0046] Figure 3 UV-Vis absorption spectra of the probe HDTVB (1 x 10 -5 mol / L) in different solvents.

[0047] Figure 4 Fluorescence emission spectra of the probe HDTVB (1 x 10 -5Fluorescence emission spectra of probe HDTVB (1 x 10

[0048] Figure 5 Fluorescence emission spectra of probe HDTVB (1 x 10 -5 UV-Vis absorption spectra of probe HDTVB (1 x 10

[0049] Figure 6 Fluorescence emission spectra of probe HDTVB (1 x 10 -5 UV-Vis absorption spectra of probe HDTVB (1 x 10

[0050] Figure 7 Fluorescence emission spectra of probe HDTVB (1 x 10 -5 UV-Vis absorption spectra of probe HDTVB (1 x 10

[0051] Figure 8 Fluorescence emission spectra of probe HDTVB (1 x 10 -5 UV-Vis absorption spectra of probe HDTVB (1 x 10

[0052] Figure 9 Photographs of probe HDTVB (1 x 10 -5 Photographs of probe HDTVB (1 x 10

[0053] Figure 10 Photographs of probe HDTVB (1 x 10 -5 Photographs of probe HDTVB (1 x 10

[0054] Figure 11 Photographs of probe HDTVB (1 x 10 -5 Photographs of probe HDTVB (1 x 10

[0055] Figure 12 UV-Vis absorption spectra of probe HDTVB (1 x 10 -5 UV-Vis absorption spectra of probe HDTVB (1 x 10

[0056] Figure 13 Photographs of probe HDTVB (1 x 10-5 Fluorescence emission spectra of PBS buffer solutions at different pH values ​​(mol / L, 1mM cetyltrimethylammonium bromide) at an excitation wavelength of 370 nm.

[0057] Figure 14 It is a probe HDTVB (1×10) -5 Fluorescence emission spectra of PBS buffer solutions at different pH values ​​(mol / L, 1mM cetyltrimethylammonium bromide) at an excitation wavelength of 540 nm.

[0058] Figure 15 It is a probe HDTVB (1×10) -5 The ratio of maximum emission fluorescence intensity I of mol / L, 1mM hexadecyltrimethylammonium bromide under two excitations 480 / I 650 Graph showing changes with pH.

[0059] Figure 16 It is a probe HDTVB (1×10) -5 mol / L, 1mM hexadecyltrimethylammonium bromide) in a pH range of 5-8 480 / I 650 Linear relationship graph.

[0060] Figure 17 It is a probe HDTVB (1×10) -5 pH cycle count was determined using a mol / L, 1mM cetyltrimethylammonium bromide (CT) assay.

[0061] Figure 18 It is a probe HDTVB (1×10) -5 Study on the anti-interference effect of mol / L, 1mM hexadecyltrimethylammonium bromide on small biological molecules. From left to right: blank, H2O2, Ala, Arg, Asp, Cys, Gln, Gly, GSH, Leu, Met, Phe, Pro, Ser, Val, Trp, Lys, Glu.

[0062] Figure 19 It is a probe HDTVB (1×10) -5 Study on the anti-interference effect of mol / L, 1mM hexadecyltrimethylammonium bromide on metal ions. From left to right: blank, Na + K + Ca 2+ Mg 2+ Al 3+ Zn 2+ Cd 2+ Ni 2+ Sn 2+ Fe 2+ Fe3+ Co 2 + Cu 2+ Mn 2+ Pb 2+ .

[0063] Figure 20 is the study of the anti-interference of probe HDTVB (1 x 10 -5 mol / L, 1 mM cetyl trimethyl ammonium bromide) to silver ions. From left to right, respectively, blank, F - Br - I - CO3 2- HCO3 - PO4 3- H2PO4 - SO4 2- Cl - NO2 - NO3 - BF4 - C2O4 2- SCN - S2O8 2- CrO4 2- ClO - P2O7 4- Cr2O7 2- S 2- HS - .

[0064] Figure 21 is the study of the stability of probe HDTVB (1 x 10 -5 mol / L, 1 mM cetyl trimethyl ammonium bromide) in PBS buffer solution with pH = 5.

[0065] Figure 22 is the study of the stability of probe HDTVB (1 x 10 -5 mol / L, 1 mM cetyl trimethyl ammonium bromide) in PBS buffer solution with pH = 7.

[0066] Figure 23 is the study of the stability of probe HDTVB (1 x 10 -5 mol / L, 1 mM cetyl trimethyl ammonium bromide) in PBS buffer solution with pH = 9.

[0067] Figure 24 in turn shows the optical physical properties of the prepared probe HDTVB (1 x 10 -5 mol / L) in different solvents, including the maximum absorption peak λ abs,max the maximum emission λem,max , Stokes shift and fluorescence quantum yield Φ (with quinine sulfate as reference).

[0068] Figure 25 The photophysical properties of the prepared probe HDTVB (1 x 10 -5 mol / L) in different solvents are sequentially shown, including the maximum absorption peak λ abs,max , the maximum emission λ em,max , the Stokes shift and the fluorescence quantum yield Φ (with rhodamine B as reference).

[0069] DETAILED DESCRIPTION

[0070] Example 1: Synthesis of compound A1

[0071] 2-Iodoethanol was measured into a round-bottom flask containing 1,1,2-trimethyl-1H- benzo[e]indole and toluene, ultrasonic dissolution, vacuum, heated to reflux for about 6 hours. After the reaction was completed, cooled to room temperature, there was a precipitate, suction filtration and washed with chloroform, dried under vacuum to get blue-gray solid 3-(2-hydroxyethyl)-1,1,2-trimethyl-1H-benzo[e] indol-3-ium iodide A1 (72.2%).

[0072] Example 2: Synthesis of compound A2

[0073] 1-(4-bromophenyl)-1,2,2-triphenylstyrene and 5-formyl-2-thiophene boronic acid were weighed and ultrasonically dissolved in tetrahydrofuran solution. Potassium carbonate aqueous solution and tetrakis(triphenylphosphine)palladium were sequentially added, ultrasonic dissolution, vacuum, reflux for about 24 hours. After the reaction was completed, the reaction solution was cooled to room temperature and rotary evaporated to obtain the crude product, which was separated and purified by column chromatography, and dried to obtain a yellow solid product 5-(4-(1,2,2-triphenylvinyl)phenyl)thiophene-2-carbaldehyde A2 (23.4%).

[0074] Example 3: Synthesis of probe HDTVB

[0075] A1 was added to a round-bottom flask containing anhydrous ethanol, heated to reflux at 55°C until A1 was dissolved. A2 was accurately weighed and added to the reaction system, and was completely dissolved, and was heated to reflux for 48 hours. At the end of the reaction, the reaction solution was cooled to room temperature, a large amount of precipitate was precipitated and suction filtered and washed to obtain the target product. It was placed in a vacuum drying oven to dry, and a red solid (E)-3-(2-hydroxyethyl)-1,1-dimethyl-2-(2-(5-(4-(1,2,2-triphenylvinyl)phenyl)thiophen-2-yl)vinyl)-1H-benzo[e]indol-3-ium iodide HDTVB (62.8%) was obtained.

[0076] Example 4: Application of probe HDTVB to detect polarity and pH in solution

[0077] Polarities of the solutions: Figure 3 UV-Vis absorption spectra of probe HDTVB (1 x 10 -5 mol / L) in different solvents. The UV absorption spectra of the probe in different solvents have obvious differences. Figure 4 Fluorescence emission spectra of probe HDTVB (1 x 10 -5 mol / L) in different solvents under an excitation wavelength of 370 nm. Figure 5 Fluorescence emission spectra of probe HDTVB (1 x 10 -5 mol / L) in different solvents under an excitation wavelength of 540 nm. Figure 6 UV-Vis absorption spectra of probe HDTVB (1 x 10 -5 mol / L, 1 mM cetyltrimethylammonium bromide) in mixed solvents of dimethyl sulfoxide and toluene with different proportions. Figure 7 Fluorescence emission spectra of probe HDTVB (1 x 10 -5 mol / L, 1 mM cetyltrimethylammonium bromide) in mixed solvents of dimethyl sulfoxide and toluene under an excitation wavelength of 350 nm. The fluorescence intensity gradually increases with the increase of the toluene content. Figure 8 Fluorescence emission spectra of probe HDTVB (1 x 10 -5 mol / L, 1 mM cetyltrimethylammonium bromide) in mixed solvents of dimethyl sulfoxide and toluene under an excitation wavelength of 520 nm. The fluorescence intensity gradually increases with the increase of the toluene content. Figure 9 Photos of probe HDTVB (1 x 10 -5 mol / L, 1 mM cetyltrimethylammonium bromide) under sunlight and a handheld ultraviolet lamp with the gradual increase of the toluene content. The solution presents regular color changes under the naked eye, and the fluorescence intensity under the handheld ultraviolet lamp increases with the increase of the toluene content. Figure 10 Photos of probe HDTVB (1 x 10 -5 mol / L, 1 mM cetyltrimethylammonium bromide) under sunlight, a laser pointer, and a handheld ultraviolet lamp in pure dimethyl sulfoxide and 1% dimethyl sulfoxide and 99% toluene. It can be concluded that the probe has obvious aggregation effect in 1% dimethyl sulfoxide and 99% toluene, producing the Tyndall effect. Figure 11 Photos (A) and particle size analysis diagram (B) of probe HDTVB (1 x 10 -5 mol / L) in 1% dimethyl sulfoxide and 99% toluene under a transmission electron microscope. It can be concluded that the probe has obvious aggregation phenomenon and large particle size in this system. Figure 12 Photos of probe HDTVB (1 x 10 -5The UV-Vis absorption spectra of the probe HDTVB (mol / L, 1mM hexadecyltrimethylammonium bromide) in PBS buffer solutions at different pH values ​​were obtained. The UV spectrum of the probe HDTVB showed a regular change with pH variation. Figure 13 It is a probe HDTVB (1×10) -5 Fluorescence emission spectra of PBS buffer solutions at different pH values ​​(mol / L, 1mM hexadecyltrimethylammonium bromide) at an excitation wavelength of 370 nm. The fluorescence intensity gradually increases with increasing pH. Figure 14 It is a probe HDTVB (1×10) -5 Fluorescence emission spectra of PBS buffer solutions at different pH values ​​(mol / L, 1mM hexadecyltrimethylammonium bromide) at an excitation wavelength of 540 nm. The fluorescence intensity gradually decreases with increasing pH. Figure 15 It is a probe HDTVB (1×10) -5 The ratio of maximum emission fluorescence intensity I of mol / L, 1mM hexadecyltrimethylammonium bromide under two excitations 480 / I 650 Graph showing changes with pH. Figure 16 It is a probe HDTVB (1×10) -5 mol / L, 1mM hexadecyltrimethylammonium bromide) in a pH range of 5-8 480 / I 650 The graph shows a linear relationship. A good linear relationship can be observed from the graph. Figure 17 It is a probe HDTVB (1×10) -5 The pH test was performed using a 1 mM cetyltrimethylammonium bromide (mol / L) cyclic assay. The graph shows that the probe can be cycled three times within the pH range of 5 and 8, demonstrating good reproducibility. Figure 18 It is a probe HDTVB (1×10) -5 The study investigated the anti-interference properties of HDTVB (1 mol / L, 1 mM cetyltrimethylammonium bromide) against small biological molecules. From left to right, the substances are blank, H₂O₂, Ala, Arg, Asp, Cys, Gln, Gly, GSH, Leu, Met, Phe, Pro, Ser, Val, Trp, Lys, and Glu. None of the interfering substances affected the fluorescence intensity of HDTVB, indicating that the probe HDTVB exhibits good anti-interference properties against small biological molecules. Figure 19 It is a probe HDTVB (1×10) -5 Study on the anti-interference effect of mol / L, 1mM hexadecyltrimethylammonium bromide on metal ions. From left to right: blank, Na + K + Ca 2+ Mg 2+ Al 3+ Zn2+ , Cd 2+ , Ni 2+ , Sn 2+ , Fe 2+ , Fe 3+ , Co 2+ , Cu 2+ , Mn 2+ , Pb 2+ . The interference of the above-mentioned substances on the fluorescence intensity of HDTVB is not obvious, which indicates that the probe HDTVB has good anti-interference ability to metal ions. Figure 20 is the anti-interference ability of the probe HDTVB (1 × 10 -5 mol / L, 1 mM cetyl trimethyl ammonium bromide) to silver ions. From left to right, blank, F - , Br - , I - , CO3 2- , HCO3 - , PO4 3- , H2PO4 - , SO4 2- , Cl - , NO2 - , NO3 - , BF4 - , C2O4 2- , SCN - , S2O8 2- , CrO4 2- , ClO - , P2O7 4- , Cr2O7 2- , S 2- , HS - . The interference of the above-mentioned substances on the fluorescence intensity of HDTVB is not obvious, which indicates that the probe HDTVB has good anti-interference ability to biological small molecules. Figure 21 is the stability of the probe HDTVB (1 × 10 -5 mol / L, 1 mM cetyl trimethyl ammonium bromide) in PBS buffer solution with pH = 5. Within 1 hour, the fluorescence intensity of the probe at different temperatures has no obvious change, which indicates that the probe HDTVB has good stability in PBS buffer solution with pH = 5. Figure 22 is the stability of the probe HDTVB (1 × 10 -5 mol / L, 1 mM cetyl trimethyl ammonium bromide) in PBS buffer solution with pH = 7. Within 1 hour, the fluorescence intensity of the probe at different temperatures has no obvious change, which indicates that the probe HDTVB has good stability in PBS buffer solution with pH = 7. Figure 23 is the stability of the probe HDTVB (1 × 10-5 The stability of the probe HDTVB (1 x 10~5mol / L, 1 mM cetyl trimethyl ammonium bromide) in PBS buffer solution at pH = 9 was studied. The fluorescence intensity of the probe did not change greatly at different temperatures within 1 hour, which indicated that the probe HDTVB had good stability in PBS buffer solution at pH = 9. Figure 24 The photophysical properties of the prepared probe HDTVB (1 x 10~5mol / L) in different solvents were shown in turn, including the maximum absorption peak λ -5 abs,max , the maximum emission λ em,max , the Stokes shift and the fluorescence quantum yield Φ (with quinine sulfate as reference). Figure 25 The photophysical properties of the prepared probe HDTVB (1 x 10~5mol / L) in different solvents were shown in turn, including the maximum absorption peak λ -5 abs,max , the maximum emission peak λ em,max , the Stokes shift and the fluorescence quantum yield Φ (with rhodamine B as reference).

[0078] In summary, by using a simple organic synthesis method, we obtained a pH and polarity dual-responsive fluorescent probe HDTVB. The probe has obvious solvatochromic phenomenon in different solvents, which can be observed by the naked eye, which indicates that the probe exhibits different optical properties in solvents with different polarity. Secondly, with the increase of toluene solvent, the fluorescence intensity of the probe at different wavelengths is enhanced, which is due to the aggregation of the probe in the solvent, which leads to the restriction of intramolecular torsion, resulting in the generation of aggregation-induced phenomenon, which is also verified by particle size distribution and Tyndall effect. HDTVB has obvious regular changes in UV absorption spectrum and fluorescence emission spectrum in different pH buffer solutions, which provides a good tool for detecting pH fluctuations. The preparation of HDTVB fills the gap in the field of fluorescent probes that can simultaneously quantitatively detect pH and polarity, and the aggregation-induced characteristics of the probe make it exhibit excellent optical properties, with a large Stokes shift, which can be repeatedly used in the response process of pH.​​

Claims

1. A pH- and polarity-responsive fluorescent probe (E)-3-(2-hydroxyethyl)-1,1-dimethyl-2-(2-(5-(4-(1,2,2-triphenylvinyl)phenyl)thiophene-2-yl)vinyl)-1H-benzo[e]indole-3-onium iodide HDTVB with aggregation-inducing properties, wherein the fluorescent probe has the following structural formula:

2. The method for preparing a pH and polarity dual-responsive fluorescent probe with aggregation-inducing properties as described in claim 1, characterized in that, Includes the following steps: 2-Iodoethanol and 1,1,2-trimethyl-1H-benzo[e]indole were dissolved in toluene, sonicated and then heated under vacuum to allow the reaction to proceed. After the reaction was complete, the mixture was cooled to room temperature, and a precipitate was formed. The precipitate was filtered, washed with chloroform, and dried in a vacuum drying oven to obtain a blue-gray solid 3-(2-hydroxyethyl)-1,1,2-trimethyl-1H-benzo[e]indole-3-onium iodide A1. 1-(4-bromophenyl)-1,2,2-triphenylphenyl and 5-aldehyde-2-thiopheneboronic acid were sonicated to fully dissolve in tetrahydrofuran (THF) solution. Potassium carbonate aqueous solution and tetra(triphenylphosphine)palladium were added and sonicated to dissolve under vacuum. The mixture was then refluxed for 24 hours. After the reaction was completed, the reaction solution was cooled to room temperature and evaporated to dryness to obtain the crude product. The crude product was separated and purified by column chromatography and dried to obtain the yellow solid product 5-(4-(1,2,2-triphenylvinyl)phenyl)thiophene-2-carboxaldehyde A2. Add A1 to anhydrous ethanol and heat under reflux until dissolved. Then add A2 to the reaction system and let it dissolve completely. Heat under reflux for 48 hours. When the reaction is finished, cool the original reaction solution to room temperature. A large amount of precipitate will precipitate out and be filtered and washed. The precipitate will be dried in a vacuum drying oven to obtain a red solid (E)-3-(2-hydroxyethyl)-1,1-dimethyl-2-(2-(5-(4-(1,2,2-triphenylvinyl)phenyl)thiophene-2-yl)vinyl)-1H-benzo[e]indole-3-onium iodide HDTVB. The synthesis path is as follows:

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