Application of a supramolecular gel in selective recognition of sialic acid and sialic acid sugar chains

Abstract

The present invention provides an application of supramolecular gel in selectively identifying sialic acid and sialic acid sugar chains, wherein gelling factors are added to a series of prepared sugar solutions; changes in fluorescence spectrum signals during the formation of supramolecular gel are monitored by a fluorescence spectrophotometer; the morphology of supramolecular gel is observed by a helium ion microscope and an atomic force microscope; and the action sites of gelling factors and sialic acid are analyzed by nuclear magnetic titration. The present invention uses a supramolecular gel based on pyrene histidine as a dynamic response system, and sialic acid or sialic acid sugar chains are combined with pyrene histidine molecules in the assembly through intermolecular hydrogen bonding, thereby preventing the orderly accumulation of gelling factors, and finally achieving effective recognition of sialic acid and sialic acid sugar chains.

Description

Technical Field

[0001] The present invention relates to the fields of material preparation technology and detection technology, and specifically to the application of a supramolecular gel in selectively identifying sialic acid and sialic acid sugar chains. Background Art

[0002] Controllable self-assembly system and its functionalization is a cutting-edge research topic, which has attracted many researchers to conduct extensive and in-depth exploration. Supramolecular gel is one of the most eye-catching ones. As a typical soft matter, supramolecular gel is favored by people because of its dynamic and controllable self-assembly structure, good biocompatibility and significant sol-gel transition. It has potential application prospects in drug delivery, tissue engineering and three-dimensional cell culture scaffolds. These carefully designed gels can self-assemble into various fine micro- and nanostructures. It is worth thinking about how to establish the relationship between structure and performance and give the assembly more advanced functions. At present, many studies have developed a series of smart supramolecular gels that can respond to external stimuli (such as temperature, light, ultrasound, pH and solvent) by introducing special functional units, which greatly expands its application in optoelectronics, catalysis, drug delivery and biosensing. However, compared with these drastic physical and chemical stimuli, the sensitivity and selectivity of supramolecular gels to biomolecules are obviously insufficient. Due to the wide variety of biomolecules and the difficulty in identifying them, although some glucose and enzyme stimuli-responsive gels have been reported, they are still far from meeting the needs of biologists, which greatly limits their applications in biochemistry and biomedicine. Therefore, it is necessary to develop supramolecular gels that can specifically and accurately identify various biomolecules.

[0003] In nature, the surface of mammalian cells is covered with a dense layer of sugar chains, which transmit important information to cells in the form of glycoproteins and glycolipids, thereby regulating various cellular processes. Sugar chains show amazing structural diversity, with different types of terminal or internal monosaccharide sequences. It is worth mentioning that sialic acid, which has a total of 9 carbon atom skeletons, stands out, among which N-acetylneuraminic acid (Neu5Ac), N-glycolylneuraminic acid (Neu5Gc) and 2-keto-3-deoxy-D-glycero-D-galacturonic acid nonanoic acid (KDN) are the three main forms of sialic acid, and Neu5Ac is almost the only form found in humans. Sialic acid is usually located at the end of the sugar chain, and its abnormal expression is closely related to a variety of diseases, including cancer, diabetes, and neurological diseases. This outermost position and wide distribution make sialic acid easily a target for pathogenic microbial binding and tumor immunotherapy. Therefore, the design and development of smart materials that can accurately recognize sialic acid and sialic acid sugar chains are of great significance in both early diagnosis and targeted treatment of diseases.

[0004] However, the development of artificial materials that can accurately recognize sialic acid and sialic acid glycans is extremely challenging due to the subtle structural differences between various sialic acid derivatives, as well as the complex composition and ultra-low abundance of sugar chains. Notably, no supramolecular gel system that can specifically respond to sialic acid and sialic acid glycans has been reported. Recently, the synthetic molecule, pyrene histidine (PyHis), has attracted our attention due to its excellent self-assembly ability and fluorophore. On the one hand, the PyHis molecule contains L-histidine, which we speculated may have a unique interaction with sialic acid, which lays the foundation for its specific recognition of sialic acid. On the other hand, since the PyHis molecule contains a pyrene fluorophore, it emits a strong aggregated fluorescence signal at 500 nm during the self-assembly process, which helps to dynamically monitor the gelation process by fluorescence spectrophotometry. Here, we report for the first time a dynamic response system based on L-PyHis that can selectively respond to sialic acid and sialic acid glycans. The gelator (L-PyHis) was prepared by a one-step method and has a strong self-assembly ability. The addition of neutral monosaccharides did not affect the self-assembly and gelation of L-PyHis, while the addition of sialic acid and sialic acid sugar chains led to a significant increase in the fluorescence intensity of L-PyHis monomers at 410 nm, and the collapse of the gel could be observed by helium ion microscopy (HIM) and atomic force microscopy (AFM). NMR titration analysis showed that sialic acid or sialic acid sugar chains could tightly interact with PyHis molecules through multiple hydrogen bonds, thus preventing the orderly stacking of the gelator. This work preliminarily demonstrated that supramolecular gels can be used for the specific recognition of sialic acid and sialylated glycans, indicating that supramolecular assembly is a good platform for biomolecular recognition and may help improve its potential for application in tumor diagnosis and targeted drugs. Summary of the invention

[0005] The purpose of the present invention is to provide a method for applying a supramolecular gel in selectively identifying sialic acid and sialic acid sugar chains. The present invention uses self-assembly technology as a means to prepare a supramolecular gel for specific response to sialic acid and sialic acid sugar chains. The present invention uses a supramolecular gel based on pyrene histidine as a dynamic response system, and sialic acid or sialic acid sugar chains are combined with pyrene histidine molecules in the assembly through intermolecular hydrogen bonding, thereby preventing the orderly accumulation of gel factors, and finally achieving effective recognition of sialic acid and sialic acid sugar chains.

[0006] The technical solution adopted by the present invention is:

[0007] The invention discloses an application of a supramolecular gel in selectively identifying sialic acid and sialic acid sugar chains. The supramolecular gel selectively identifies sialic acid and sialic acid sugar chains.

[0008] The gel factor is dissolved in anhydrous ethanol, heated until completely dissolved, and then a series of prepared sugar solutions are added; the change of the fluorescence spectrum signal during the formation of the supramolecular gel is monitored by a fluorescence spectrophotometer; the morphology of the supramolecular gel is observed by a helium ion microscope and an atomic force microscope; and the action sites of the gel factor and sialic acid are analyzed by nuclear magnetic titration. The sugar solution includes neutral monosaccharides, sialic acid monosaccharides, disaccharides and sialic acid sugar chains.

[0009] The preparation steps of the supramolecular gel are as follows:

[0010] Step 1: Preparation of gel factor:

[0011] L-histidine methyl ester dihydrochloride is dissolved in dry dichloromethane, and triethylamine is added, and the mixture is stirred at room temperature for 1 hour; then 1-pyrenecarboxylic acid, 1-hydroxybenzotriazole and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride are added in sequence, and the mixed solution is stirred at room temperature overnight; the reaction mixture is washed with a saturated sodium bicarbonate aqueous solution; the organic phase is collected and dried over anhydrous sodium sulfate, filtered and the solvent is removed by a rotary evaporator, and the residue is purified by a silica gel column to obtain a crude product, and finally recrystallized to obtain a light yellow final product;

[0012] Step 2: Self-assembly of gel factor:

[0013] The gel factor of step 1 was dissolved in anhydrous ethanol, heated until completely dissolved, and then ultrapure water was added to immediately form a transparent supramolecular gel.

[0014] In the step 1, the molar ratio of the added amounts of reactants L-histidine methyl ester dihydrochloride, triethylamine, 1-pyrenecarboxylic acid, 1-hydroxybenzotriazole and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride is 1:2-3:0.5-1:1-2:1-2; the amount of dichloromethane used is 250 mL; the saturated sodium bicarbonate aqueous solution is washed 3 times, each time with 250 mL; the silica gel column eluent is dichloromethane and methanol; and the recrystallization solvent is methanol.

[0015] In the step 2, the concentration of the gel factor is 0.04 M, the heating temperature is 50° C., and the volume ratio of anhydrous ethanol to ultrapure water is 1:4.

[0016] The supramolecular gel is used for the recognition of sialic acid and sialic acid sugar chains, wherein the concentration of the gel factor is 0.04M; the heating temperature is 50°C; the concentration of a series of sugar solutions is 1mM; the volume ratio of anhydrous ethanol to the sugar solution is 1:4; when monitoring the change of fluorescence spectrum signal during the formation of the supramolecular gel, the final concentration of the gel factor is 8mM, the final concentration of a series of sugar solutions is 0.8mM, and the solution volume ratio is 1:4; when observing the morphology of the supramolecular gel using a helium ion microscope and an atomic force microscope, the final concentration of the gel factor is 0.8mM, the final concentration of the sugar solution is 0.8mM, and the solution volume ratio is 1:4; when analyzing the action sites of the gel factor and sialic acid by nuclear magnetic titration, the final concentration of the gel factor is 0.02M, the final concentration of sialic acid is 0.02M, and they are dissolved in deuterated dimethyl sulfoxide at a molar ratio of 1:1. The sugar solution includes glucose (Glu), galactose (Gal), N-acetylneuraminic acid (Neu5Ac), N-glycolylneuraminic acid (Neu5Gc), 2-keto-3-deoxy-D-glycero-D-galacturonosylnonanoic acid (KDN), lactose and 2,3' sialic acid triose.

[0017] The invention adopts self-assembly technology to prepare supramolecular gel, which presents gel-like shape in macroscopic view and nanofiber-like shape in microscopic view, and has the ability of selectively identifying sialic acid and sialic acid sugar chain.

[0018] Using self-assembly technology, a fluorescent dynamic response system based on PyHis supramolecular gel was constructed. Driven by π-π stacking and intermolecular hydrogen bonds, PyHis has a strong self-assembly ability and forms a stable gel. When N-acetylneuraminic acid (a typical sialic acid) is added, it tightly interacts with the two PyHis molecules in the assembly through multiple hydrogen bonds, thereby preventing the orderly stacking of PyHis; other monosaccharides or sialic acid analogs have no obvious effect on this. Importantly, sialylated glycans also have a significant inhibitory effect on the formation of gels, highlighting the high selectivity of the gel dynamic response system.

[0019] Technical advantages of the present invention:

[0020] The advantage is that the supramolecular gel achieves accurate identification of sialic acid and sialic acid sugar chains based on the significant change in fluorescence intensity. The change in fluorescence intensity is caused by the self-assembly ability of the gel factor. The lower the self-assembly ability of the gel factor, the stronger the emission peak of the monomer.

[0021] This supramolecular gel has a specific reaction to sialic acid and sialic acid sugar chains, and may be further developed into a new tool for the detection and analysis of complex sialylated glycans; at the same time, this work provides a new idea for the recognition of complex biomolecules from the perspective of supramolecular assembly, that is, an intelligent supramolecular assembly platform can be constructed by introducing specific functional units, which is helpful for the detection or analysis of other important biomolecules. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 : Molecular structure of gel factor (L-PyHis);

[0023] Figure 2 :Helium ion microscopy images of supramolecular gels;

[0024] Figure 3 :Atomic force microscopy images of supramolecular gels;

[0025] Figure 4 :The formation process of supramolecular gel was monitored by fluorescence instrument;

[0026] Figure 5 :The formation process of supramolecular gel after adding glucose (Glu) was monitored by fluorescence instrument;

[0027] Figure 6 :The formation process of supramolecular gel after adding galactose (Gal) was monitored by fluorescence instrument;

[0028] Figure 7 :The formation process of supramolecular gel after adding N-acetylneuraminic acid (Neu5Ac) was monitored by fluorescence instrument;

[0029] Figure 8 :The formation process of supramolecular gel after adding N-glycolylneuraminic acid (Neu5Gc) was monitored by fluorescence instrument;

[0030] Fig. 9 :The formation process of supramolecular gel after adding 2-keto-3-deoxy-D-glycero-D-galacturonic acid nonanoic acid (KDN) was monitored by fluorescence instrument;

[0031] Fig.10 : Fluorometer was used to monitor the formation process of supramolecular gel after adding lactose;

[0032] Fig.11 :The formation process of supramolecular gel after adding 2,3' sialic acid trisaccharide was monitored by fluorescence instrument;

[0033] Fig.12 : Helium ion microscopy image of supramolecular gel after adding N-acetylneuraminic acid (Neu5Ac);

[0034] Fig.13: Helium ion microscopy image of supramolecular gel after adding lactose;

[0035] Fig.14 : Helium ion microscopy image of supramolecular gel after adding 2,3' sialic acid trisaccharide;

[0036] Fig.15 : Atomic force microscopy image of supramolecular gel after adding N-acetylneuraminic acid (Neu5Ac);

[0037] Fig.16 : Atomic force microscopy image of supramolecular gel after adding lactose;

[0038] Fig.17 : Atomic force microscopy image of supramolecular gel after adding 2,3' sialic acid trisaccharide;

[0039] Fig.18 : One-dimensional H-NMR spectra of gel factor, N-acetylneuraminic acid (Neu5Ac) and their mixture in equimolar ratio. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. Raw materials and equipment used in the embodiments: L-histidine methyl ester dihydrochloride, 1-hydroxybenzotriazole (HOBt) and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC·HCl) were purchased from Aladdin Reagent (Shanghai). 1-Pyrenecarboxylic acid was purchased from Beijing Inokai Technology Co., Ltd. Glucose (Glu), galactose (Gal), lactose, N-acetylneuraminic acid (Neu5Ac), N-glycolylneuraminic acid (Neu5Gc), 2-keto-3-deoxy-D-glycero-D-galacturonic acid (KDN) and 3'-sialyllactose sodium salt were purchased from TCI (Shanghai) Chemical Industry Development Co., Ltd. Fluorescence data were recorded by PerkinElmer FL-6500 fluorescence spectrophotometer. Helium ion microscope (HIM) images were obtained by ORIONNANOFAB. Atomic force microscopy (AFM) images were obtained by JPK NanoWizard Ultra Speed ​​AFM. Nuclear magnetic resonance (NMR) spectra were recorded on a Bruker AVANCE III 400M NMR spectrometer.

[0041] Example 1

[0042] A method for preparing a supramolecular gel and its application are carried out according to the following steps:

[0043] Step 1: Preparation of gel factor:

[0044] Add L-histidine methyl ester dihydrochloride to a round-bottom flask, dissolve in dry dichloromethane, add triethylamine, and stir at room temperature for 1 hour. Then add 1-pyrenecarboxylic acid, 1-hydroxybenzotriazole and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride in sequence, and stir the mixed solution overnight at room temperature. Wash the reaction mixture with saturated sodium bicarbonate aqueous solution. Collect the organic phase and dry it with anhydrous sodium sulfate, filter it, remove the solvent with a rotary evaporator, and purify the residue with a silica gel column to obtain a crude product, and finally recrystallize to obtain a light yellow final product.

[0045] Step 2: Self-assembly of gel factor:

[0046] The gel factor of step 1 was dissolved in anhydrous ethanol, heated until completely dissolved, and then ultrapure water was added to immediately form a transparent supramolecular gel.

[0047] Step 3: Sialic acid and sialic acid sugar chain recognition in supramolecular gel:

[0048] The gelling factor of step 1 is dissolved in anhydrous ethanol, heated until completely dissolved, and then a series of prepared sugar solutions are added, including neutral monosaccharides, sialic acid monosaccharides, disaccharides and sialic acid sugar chains; the changes in the fluorescence spectrum signal during the formation of the supramolecular gel are monitored by a fluorescence spectrophotometer; the morphology of the supramolecular gel is observed by a helium ion microscope and an atomic force microscope; and the action sites of the gelling factor and sialic acid are analyzed by nuclear magnetic titration.

[0049] In step 1, the molar ratio of the added amounts of reactants L-histidine methyl ester dihydrochloride, triethylamine, 1-pyrenecarboxylic acid, 1-hydroxybenzotriazole and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride is 1:2-3:0.5-1:1-2:1-2; the amount of dichloromethane used is 250 mL; the saturated sodium bicarbonate aqueous solution is washed 3 times, 250 mL each time; the silica gel column eluent is dichloromethane and methanol; the recrystallization solvent is methanol.

[0050] In step 2, the concentration of the gel factor is 0.04 M, the heating temperature is 50° C., and the volume ratio of anhydrous ethanol to ultrapure water is 1:4.

[0051] In step 3, supramolecular gel is used for the recognition of sialic acid and sialic acid sugar chains, the concentration of the gel factor is 0.04M; the heating temperature is 50°C; the concentration of a series of sugar solutions prepared is 1mM, including glucose (Glu), galactose (Gal), N-acetylneuraminic acid (Neu5Ac), N-hydroxyacetylneuraminic acid (Neu5Gc), 2-keto-3-deoxy-D-glycero-D-galacturonic acid nonanoic acid (KDN), lactose and 2,3' sialic acid triose; the volume ratio of anhydrous ethanol to sugar solution is 1:4. When monitoring the changes in fluorescence spectral signals during the formation of supramolecular gel, the final concentration of the gel factor was 8 mM, the final concentration of a series of sugar solutions was 0.8 mM, and the solution volume ratio was 1:4; when observing the morphology of supramolecular gel using helium ion microscopy and atomic force microscopy, the final concentration of the gel factor was 0.8 mM, the final concentration of the sugar solution was 0.8 mM, and the solution volume ratio was 1:4; when analyzing the action sites of the gel factor and sialic acid by nuclear magnetic titration, the final concentration of the gel factor was 0.02 M, and the final concentration of sialic acid was 0.02 M, dissolved in deuterated dimethyl sulfoxide, with a molar ratio of 1:1.

[0052] Embodiment 2:

[0053] Preparation of gel factor

[0054] The structure of gel factor (PyHis) is shown in the attached Figure 1 As shown, taking the molar ratio of the addition of reactants L-histidine methyl ester dihydrochloride, triethylamine, 1-pyrenecarboxylic acid, 1-hydroxybenzotriazole and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride as 8.3:20.7:6.9:9.0:9.0 as an example, L-histidine methyl ester dihydrochloride (2.0 g, 8.3 mmol) was added to a dry 500 mL round-bottom flask, dissolved in 250 mL of dry dichloromethane, and then triethylamine (2.1 g, 20.7 mmol) was added, and stirred at room temperature for 1 hour. Then 1-pyrenecarboxylic acid (1.7 g, 6.9 mmol), 1-hydroxybenzotriazole (1.2 g, 9.0 mmol) and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (1.7 g, 9.0 mmol) were added in sequence, and the mixed solution was stirred at room temperature overnight. The reaction mixture was washed with saturated sodium bicarbonate aqueous solution for 3 times, 250 mL each time. The organic phase was collected and dried over anhydrous sodium sulfate, filtered and the solvent was removed by rotary evaporator, and the residue was purified by silica gel column to obtain a crude product, the eluents were dichloromethane and methanol, and finally recrystallized from anhydrous methanol to obtain a light yellow final product.

[0055] Embodiment 3:

[0056] Dissolve the gel factor (PyHis) in anhydrous ethanol at a concentration of 0.004M, heat to 50°C to completely dissolve, then add four times the volume of ultrapure water, draw 10μL and drop it on a clean glass slide to dry naturally. Figure 2 shown.

[0057] Embodiment 4:

[0058] The gel factor (PyHis) was dissolved in anhydrous ethanol at a concentration of 0.004 M, heated to 50°C to completely dissolve, and then four times the volume of ultrapure water was added. 10 μL was aspirated and dropped on a clean glass slide and allowed to dry naturally. The AFM morphology is shown in the attached figure. Figure 3 shown.

[0059] Embodiment 5:

[0060] Attached Figure 4 To monitor the formation of supramolecular gel using a fluorescence spectrophotometer, PyHis was first dissolved in ethanol to obtain a stock solution with a concentration of 0.04 M. Then, 0.8 mL of ultrapure water was added to 0.2 mL of PyHis ethanol solution. Fluorescence spectra were recorded every 2 minutes at room temperature for 1 hour in the wavelength range from 350 nm to 600 nm.

[0061] Embodiment 6:

[0062] Same as Example 5, except that 0.8 mL of ultrapure water was added instead of 0.8 mL of 1 mM glucose solution. Figure 5 shown.

[0063] Embodiment 7:

[0064] Same as Example 5, except that 0.8 mL of ultrapure water was added instead of 0.8 mL of 1 mM galactose solution. Figure 6 shown.

[0065] Embodiment 8:

[0066] Same as Example 5, except that 0.8 mL of ultrapure water was added instead of 0.8 mL of 1 mM N-acetylneuraminic acid (Neu5Ac) solution. Figure 7 shown.

[0067] Embodiment 9:

[0068] Same as Example 5, except that 0.8 mL of ultrapure water was added instead of 0.8 mL of 1 mM N-glycolylneuraminic acid (Neu5Gc) solution. Figure 8 shown.

[0069] Embodiment 10:

[0070] Same as Example 5, except that 0.8 mL of ultrapure water was added instead of 0.8 mL of 1 mM 2-keto-3-deoxy-D-glycero-D-galacturonic acid nonanoic acid (KDN) solution. Fig. 9 shown.

[0071] Embodiment 11:

[0072] Same as Example 5, except that 0.8 mL of ultrapure water was added instead of 0.8 mL of 1 mM lactose solution. Fig.10 shown.

[0073] Embodiment 12:

[0074] Same as Example 5, except that 0.8 mL of ultrapure water was added instead of 0.8 mL of 1 mM 2,3' sialic acid trisaccharide solution. Fig.11 shown.

[0075] Embodiment 13:

[0076] Same as Example 3, except that four times the volume of ultrapure water was replaced by four times the volume of N-acetylneuraminic acid (Neu5Ac) solution. The morphology of HIM is shown in the attached figure. Fig.12 shown.

[0077] Embodiment 14:

[0078] Same as Example 3, except that four times the volume of ultrapure water was added instead of four times the volume of lactose solution. The morphology of HIM is as shown in the attached figure. Fig.13 shown.

[0079] Embodiment 15:

[0080] Same as Example 3, except that four times the volume of ultrapure water was replaced by four times the volume of 2,3' sialic acid trisaccharide solution. The morphology of HIM is as shown in the attached figure. Fig.14 shown.

[0081] Embodiment 16:

[0082] Same as Example 13, AFM morphology is as shown in the attached Fig.15 shown.

[0083] Embodiment 17:

[0084] Same as Example 14, AFM morphology is as shown in the attached Fig.16 shown.

[0085] Embodiment 18:

[0086] Same as Example 15, AFM morphology is as shown in the attached Fig.17 shown.

[0087] Embodiment 19:

[0088] The gel factor (PyHis), N-acetylneuraminic acid (Neu5Ac) and their equimolar mixture were dissolved in deuterated dimethyl sulfoxide at a concentration of 0.02 M. Fig.18 It is a one-dimensional H NMR spectrum.

[0089] The embodiments are preferred implementations of the present invention, but the present invention is not limited to the above-mentioned implementations. Any obvious improvements, substitutions or modifications that can be made by those skilled in the art without departing from the essential content of the present invention belong to the protection scope of the present invention.

Claims

1. Application of a supramolecular gel in selectively identifying sialic acid and sialic acid sugar chains, characterized in that: The supramolecular gel selectively recognizes sialic acid and sialic acid sugar chains; the preparation steps of the supramolecular gel are as follows: Step 1: Preparation of gel factor: L-histidine methyl ester dihydrochloride is dissolved in dry dichloromethane, and triethylamine is added, and the mixture is stirred at room temperature for 1 hour; 1-pyrenecarboxylic acid, 1-hydroxybenzotriazole and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride are then added in sequence, and the mixed solution is stirred at room temperature overnight; the reaction mixture is washed with a saturated sodium bicarbonate aqueous solution; the organic phase is collected and dried over anhydrous sodium sulfate, filtered and the solvent is removed by a rotary evaporator, and the residue is purified by a silica gel column to obtain a crude product, and finally recrystallized to obtain a light yellow final product; Step 2: Self-assembly of gel factor: The gel factor of step 1 was dissolved in anhydrous ethanol, heated until completely dissolved, and then ultrapure water was added to immediately form a transparent supramolecular gel.

2. The use of the supramolecular gel according to claim 1 in selectively identifying sialic acid and sialic acid sugar chains, characterized in that: The gelling factor was dissolved in anhydrous ethanol, heated until completely dissolved, and then a series of prepared sugar solutions were added; the changes in the fluorescence spectrum signal during the formation of the supramolecular gel were monitored by a fluorescence spectrophotometer; the morphology of the supramolecular gel was observed by helium ion microscopy and atomic force microscopy; and the action sites of the gelling factor and sialic acid were analyzed by nuclear magnetic titration.

3. The use of the supramolecular gel according to claim 2 in selectively identifying sialic acid and sialic acid sugar chains, characterized in that: The sugar solution includes neutral monosaccharides, sialic acid monosaccharides, disaccharides and sialic acid sugar chains.

4. The use of the supramolecular gel according to claim 1 in selectively identifying sialic acid and sialic acid sugar chains, characterized in that: In step 1, the molar ratio of the added amounts of reactants L-histidine methyl ester dihydrochloride, triethylamine, 1-pyrenecarboxylic acid, 1-hydroxybenzotriazole and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride is 1:2-3:0.5-1:1-2:1-2; the amount of dichloromethane used is 250 mL; the saturated sodium bicarbonate aqueous solution is washed 3 times, 250 mL each time; the silica gel column eluent is dichloromethane and methanol; the recrystallization solvent is methanol.

5. The use of the supramolecular gel according to claim 1 in selectively identifying sialic acid and sialic acid sugar chains, characterized in that: In step 2, the concentration of the gel factor is 0.04 M, the heating temperature is 50 °C, and the volume ratio of anhydrous ethanol to ultrapure water is 1:

4.

6. Use of the supramolecular gel according to claim 2 in selectively identifying sialic acid and sialic acid sugar chains, characterized in that: The supramolecular gel is used for the recognition of sialic acid and sialic acid sugar chains, wherein the concentration of the gel factor is 0.04 M; the heating temperature is 50 °C; the concentration of a series of sugar solutions is 1 mM; the volume ratio of anhydrous ethanol to the sugar solution is 1:4; when monitoring the change of the fluorescence spectrum signal during the formation of the supramolecular gel, the final concentration of the gel factor is 8 mM, the final concentration of a series of sugar solutions is 0.8 mM, and the solution volume ratio is 1:4; when observing the morphology of the supramolecular gel using a helium ion microscope and an atomic force microscope, the final concentration of the gel factor is 0.8 mM, the final concentration of the sugar solution is 0.8 mM, and the solution volume ratio is 1:4; When analyzing the interaction sites of gel factor and sialic acid by NMR titration, the final concentration of gel factor was 0.02 M and the final concentration of sialic acid was 0.02 M, dissolved in deuterated dimethyl sulfoxide, with a molar ratio of 1:

1.

7. Use of the supramolecular gel according to claim 6 in selectively identifying sialic acid and sialic acid sugar chains, characterized in that: Sugar solution includes glucose (Glu), galactose (Gal), N -Acetylneuraminic acid (Neu5Ac), N -glycolylneuraminic acid (Neu5Gc), 2-keto-3-deoxy-D-glycero-D-galacturonosylnonanoic acid (KDN), lactose, and 2,3' sialic acid triose.

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