A metal ion independent supramolecular hydrogel and its preparation method and application

Abstract

The application provides a metal ion independent supramolecular hydrogel and a preparation method and application thereof, and belongs to the field of biomedical materials. The guanosine supramolecular hydrogel is prepared from 8-hydroxyguanosine or 8-aminoguanosine, boric acid and water in a weak alkali environment with a pH value of 7.5-8, and the ratio of 8-hydroxyguanosine or 8-aminoguanosine, boric acid and water is (0.025-0.1) mmol:(0.0125-0.1) mmol:1000 muL. The supramolecular hydrogel prepared from 8-hydroxyguanosine (C8) instead of guanosine derivatives can be gelled without metal ions, and also has good mechanical properties, so that the supramolecular hydrogel has a wide application prospect.

Description

Technical Field

[0001] This invention belongs to the field of biomedical materials, specifically relating to a supramolecular hydrogel that does not depend on metal ions, its preparation method, and its applications. Background Technology

[0002] Supramolecular hydrogels are a class of physical gels formed by the hierarchical, stepwise self-assembly of low-molecular-weight gelling agents through non-covalent bonds such as hydrogen bonding, hydrophobic interactions, π-π stacking, and cation-π interactions. They possess self-healing, viscoelastic, and injectable properties, and are widely used in biomedicine, environmental science, and sensors. Guanosine and its derivatives have unique base structures that enable them to self-assemble into highly ordered hierarchical structures through non-covalent interactions such as hydrogen bonding and π-π stacking. These guanosines are ideal gelling agents for constructing supramolecular hydrogels, and the resulting gels are called guanosine supramolecular hydrogels.

[0003] Currently reported guanosine supramolecular hydrogels all use metal ions (such as potassium ions, sodium ions, etc.) as templates to form tetramers, which are then stacked layer by layer to form a fibrous structure, and finally form a 3D cross-linked network structure. In the prior art, guanosine supramolecular hydrogels constructed using guanosine and its derivatives as gelling agents must rely on metal ions (such as potassium ions, sodium ions, etc.) to form a stable hydrogel. For example, Chinese patent application CN108774326A discloses a self-healing injectable supramolecular hydrogel, which is prepared by weighing a certain mass of guanosine and arylboronic acid compounds, adding them to a saline or alkaline aqueous solution, heating to boiling to completely dissolve them, and then naturally cooling to prepare a supramolecular hydrogel.

[0004] However, the applications of existing guanosine supramolecular hydrogels are significantly limited due to the presence of metal ions. For example, potassium and sodium ions may cause interference when using guanosine supramolecular hydrogels for metal ion detection. Furthermore, alkali metal ions such as potassium and sodium ions are highly mobile in semiconductor materials, potentially causing semiconductor device failure. Proteins are also easily inactivated in the presence of metal ions. Therefore, the preparation of supramolecular hydrogels that are independent of metal ions is of great significance.

[0005] To overcome this problem, we have tried two methods: one is to mix two or more gelling agents, and the other is to modify the functional groups (bases or glycosyl groups) of guanosine molecules. However, neither of these methods can prepare a stable guanosine supramolecular hydrogel independently without relying on metal ions, and thus cannot effectively solve the aforementioned problem. Therefore, there is an urgent need to develop a supramolecular hydrogel that is completely independent of metal ions. Summary of the Invention

[0006] The purpose of this invention is to provide a supramolecular hydrogel that does not depend on metal ions, its preparation method, and its application.

[0007] This invention provides a guanosine supramolecular hydrogel, which is prepared from 8-hydroxyguanosine or 8-aminoguanosine, boric acid and water in a weakly alkaline environment with a pH of 7.5-8.

[0008] Furthermore, the ratio of hydrogel 8-hydroxyguanosine or 8-aminoguanosine, boric acid and water is (0.025-0.1) mmol: (0.0125-0.1) mmol: 1000 μL.

[0009] Furthermore, the ratio of the hydrogel to 8-hydroxyguanosine or 8-aminoguanosine, boric acid, and water is 0.1 mmol: 0.05 mmol: 1000 μL.

[0010] Furthermore, the weakly alkaline environment with a pH of 7.5-8 is adjusted by adding a weak alkali that does not contain metal cations;

[0011] Furthermore, the weak base that does not contain metal cations is tris(hydroxymethyl)aminomethane, wherein the molar ratio of tris(hydroxymethyl)aminomethane to boric acid is 1:1.

[0012] Furthermore, the water is deionized water.

[0013] The guanosine supramolecular hydrogel of the present invention is prepared according to the following steps: 8-hydroxyguanosine or 8-aminoguanosine is added to water and dissolved, then boric acid and a weak base without metal cations are added, dissolved, mixed, heated, and cooled to room temperature to obtain the guanosine supramolecular hydrogel.

[0014] Furthermore, the dissolution is carried out by heating.

[0015] This invention provides a method for preparing the above-mentioned guanosine supramolecular hydrogel. The preparation steps of the method are as follows: 8-hydroxyguanosine or 8-aminoguanosine is added to water and dissolved. Boric acid and a weak base without metal cations are then added, dissolved, mixed, heated, and cooled to room temperature.

[0016] This invention provides the use of the above-mentioned guanosine supramolecular hydrogel in the preparation of semiconductor materials.

[0017] This invention provides the application of the above-mentioned guanosine supramolecular hydrogel in the detection of metal ions or cysteine.

[0018] Furthermore, the metal ions include potassium ions, sodium ions, and silver ions.

[0019] The present invention also provides the use of the above-mentioned guanosine supramolecular hydrogel as a carrier for encapsulating proteins.

[0020] The guanosine supramolecular hydrogel of this invention is free of metal ions, thus avoiding interference from metal ions, particularly alkali metal ions such as potassium and sodium ions, which can migrate within semiconductor materials and cause semiconductor device failure. Therefore, the guanosine supramolecular hydrogel of this invention is of great significance for ion detection and semiconductor material preparation. Furthermore, the guanosine supramolecular hydrogel of this invention can also be used as a carrier to encapsulate proteins, and since it contains no metal ions, it will not cause protein inactivation.

[0021] The guanosine supramolecular hydrogel described in this invention exhibits excellent self-healing and shear-thinning properties, is injectable, and shows promising potential in the medical field. Furthermore, the guanosine supramolecular hydrogel of this invention demonstrates a fluorescence-switching response to silver ions and cysteine, enabling its application in portable, visualized detection of either silver ions or cysteine.

[0022] Obviously, based on the above description of the present invention, and according to common technical knowledge and conventional methods in the field, various other modifications, substitutions or alterations can be made without departing from the basic technical concept of the present invention.

[0023] The following detailed embodiments further illustrate the above-described content of the present invention. However, this should not be construed as limiting the scope of the present invention to the following examples. All technologies implemented based on the above-described content of the present invention fall within the scope of the present invention. Attached Figure Description

[0024] Figure 1 Preparation and characterization of 8OHG-T and 8AG-T hydrogels. (a) Images of 8OHG-T and 8AG-T hydrogels; (b) SEM images of 8OHG-T and 8AG-T hydrogels, scale bar: 50 μL; (c) AFM images of 8OHG-T and 8AG-T hydrogels, scale bar: 200 nm; (de) Small angle X-ray scattering results of 8OHG-T and 8AG-T hydrogels; (f) Lyophilized samples of 8OHG-T and 8AG-T hydrogels. 11 B NMR spectra (solvent: DMSO-D6); (g) Alizarin Red experimental results of 8OHG-T and 8AG-T hydrogels; (h) PXRD spectra of lyophilized samples of 8OHG-T and 8AG-T hydrogels.

[0025] Figure 2 Rheological results of 8OHG-T and 8AG-T hydrogels. (a) Frequency scanning results of 8OHG-T and 8AG-T hydrogels; (b) Strain scanning test results of 8OHG-T and 8AG-T hydrogels; (c) Self-healing test results of 8OHG-T and 8AG-T hydrogels; (d) Relationship between viscosity and shear rate of 8OHG-T and 8AG-T hydrogels.

[0026] Figure 3 Detection of silver ions and cysteine ​​using 8OHG-T hydrogel. Detailed Implementation

[0027] Example 1: Preparation method of the hydrogel of the present invention

[0028] Preparation of 8OHG-T hydrogel: 0.1 mmol of 8-hydroxyguanosine was added to 800 μL of deionized water and heated to dissolve. Then, 100 μL of 0.5 M boric acid (H3BO3) solution and 100 μL of 0.5 M tris(hydroxymethyl)aminomethane (Tris) solution were added, mixed well, and heating was continued for 5 minutes. Heating was then stopped, and the mixture was cooled to room temperature to obtain 8OHG-T hydrogel (8-hydroxyguanosine concentration 0.1 mmol / mL).

[0029] Confirm the formation of the hydrogel by inverting the vial, observe and take photos to record the process.

[0030] The results show that, by Figure 1 As can be seen from this, the 8OHG-T hydrogel remained stable after the vial was inverted, and showed no flow or collapse within 6 months.

[0031] Experimental results show that the present invention successfully constructed a guanosine supramolecular hydrogel 8OHG-T with good stability under metal ion-free conditions. The hydrogel exhibits excellent stability for at least six months.

[0032] Example 2: Preparation method of the hydrogel of the present invention

[0033] 0.2 mmol of 8-hydroxyguanosine was added to 600 μL of deionized water and heated to dissolve. Then, 200 μL of 0.5 M boric acid (H3BO3) solution and 200 μL of 0.5 M tris(hydroxymethyl)aminomethane (Tris) solution were added, mixed well, and heating was continued for 5 minutes. Heating was then stopped, and the mixture was cooled to room temperature to obtain 8OHG-T hydrogel (8-hydroxyguanosine concentration 0.2 mmol / mL).

[0034] Example 3: Preparation method of the hydrogel of the present invention

[0035] Preparation of 8AG-T hydrogel: 0.1 mmol of 8-aminoguanosine was added to 800 μL of deionized water and heated to dissolve. Then, 100 μL of 0.5 M H3BO3 solution and 100 μL of 0.5 M Tris solution were added, mixed well, and heating was continued for 5 minutes. Heating was then stopped, and the mixture was cooled to room temperature to obtain the 8AG-T hydrogel (8-aminoguanosine concentration 0.2 mmol / mL). The formation of the hydrogel was confirmed by inverting the vial.

[0036] Example 4: Preparation method of the hydrogel of the present invention

[0037] Preparation of 8AG-T hydrogel: 0.025 mmol of 8-aminoguanosine was added to 950 μL of deionized water and heated to dissolve. Then, 25 μL of 0.5 M H3BO3 solution and 25 μL of 0.5 M Tris solution were added, mixed thoroughly, and heating was continued for 5 minutes. Heating was then stopped, and the mixture was cooled to room temperature to obtain the 8AG-T hydrogel (8-aminoguanosine concentration 0.025 mmol / mL). The formation of the hydrogel was confirmed by inverting the vial.

[0038] The following experimental examples demonstrate the beneficial effects of the 8OHG-T and 8AG-T hydrogels prepared in this invention.

[0039] Experimental Example 1: Structural Characterization of Hydrogels

[0040] 1. Experimental Methods

[0041] The 8OHG-T and 8AG-T hydrogels prepared in Examples 1 and 3 were characterized by scanning electron microscopy (SEM), atomic force microscopy (AFM), and variable-temperature X-ray small-angle scattering (VT-SAXS). 11 Characterization by B NMR (solvent: DMSO-D6), alizarin red experiment, and powder X-ray diffraction analysis (PXRD).

[0042] 2. Experimental Results

[0043] SEM results showed that the 8OHG-T and 8AG-T hydrogels had a loose and porous structure. Figure 1 b). Figure 1 c shows that the 8OHG-T hydrogel has a stacked ellipsoidal structure, while the 8AG-T hydrogel has a cross-linked fibrous structure. VT-SAXS experiments show that the 8OHG-T hydrogel is a fiber with a diameter of approximately 2 nm at 85 °C. As the temperature decreases, the aggregate diameter gradually increases, and when the temperature drops to 25 °C, a larger ellipsoidal structure is formed. Figure 1 d); 8AG-T hydrogels are fibers with a diameter of approximately 2 nm at 85 °C. As the temperature decreases, the aggregate diameter gradually increases, and when the temperature drops to 25 °C, a fiber structure with an even larger diameter is formed. Figure 1 e). 11 B NMR results showed that H3BO3 had a peak at 22.72 ppm, while 8OHG-T and 8AG-T hydrogels showed two peaks in the range of 0-15 ppm. Figure 1 f); The results of the alizarin red experiment showed that the alizarin red solution had almost no fluorescence, but exhibited strong fluorescence after the addition of H3BO3, while the fluorescence intensity was significantly reduced after the addition of 8OHG-T or 8AG-T hydrogel. Figure 1g), indicating that borate diester bonds were formed in the 8OHG-T and 8AG-T hydrogels. Figure 1 h shows that the lyophilized samples of 8OHG-T and 8AG-T hydrogels in There is a peak at this point, indicating that the 8OHG-T and 8AG-T hydrogels are formed by π-π stacking.

[0044] Experimental results show that the 8OHG-T and 8AG-T hydrogels of this invention are hydrogels with a loose porous structure formed by π-π stacking, and borate diester bonds are formed.

[0045] Experimental Example 2: Mechanical Properties of Hydrogels

[0046] 1. Experimental Methods

[0047] Rheological tests were performed using an Anton Paar modular intelligent rotational rheometer (MCR302). The rheological properties of the 8OHG-T hydrogel prepared in Example 1 were analyzed at 25°C by frequency scanning, strain scanning, shear rate, and self-healing tests.

[0048] 2. Experimental Results

[0049] Frequency scanning results show that the storage modulus G′ of 8OHG-T and 8AG-T hydrogels is much greater than the loss modulus G″, indicating that the samples are in a gel state and have good solid-like mechanical properties. Figure 2 a). Figure 2 b shows the strain scan results for 8OHG-T and 8AG-T. When subjected to alternating high-strain and low-strain conditions, the changes in G′ and G″ of the samples were minimal, indicating that they could essentially recover to their initial state. This demonstrates that 8OHG-T and 8AG-T hydrogels possess good self-healing properties. Figure 2 c). Shear rate experiments showed that the viscosity of 8OHG-T and 8AG-T hydrogels gradually decreased with increasing shear rate. Figure 2 d) indicates that 8OHG-T and 8AG-T hydrogels have shear-thinning properties.

[0050] Experimental results show that the 8OHG-T and 8AG-T hydrogels of this invention have good self-healing properties and shear-thinning characteristics, making them suitable for injection and showing promising potential in the medical field.

[0051] Experimental Example 3: The Performance of Hydrogels in the Detection of Silver Ions and Cysteine

[0052] 1. Experimental Methods

[0053] Take 200 μL of the 8OHG-T hydrogel prepared in Example 1, heat it to a solution state, add 2 μL of Rhodamine 123 solution (1 mM) and mix well. Stop heating, cool to room temperature, add 50 μL of silver ion solution (10 mM) to the sample surface, observe the fluorescence under a 365 nm UV lamp and record the results. Then add 50 μL of cysteine ​​test solution (10 mM) to the sample surface, observe the fluorescence under a 365 nm UV lamp and record the results.

[0054] 2. Experimental Results

[0055] Depend on Figure 3 It can be seen that the 8OHG-T hydrogel itself has no fluorescence. After adding the fluorescent molecule Rhodamine 123, the hydrogel immediately quenches the fluorescence of Rhodamine 123. After adding the silver ion test solution, the fluorescence can be observed to recover after 10 minutes. After adding the cysteine ​​test solution, the fluorescence is quenched again after 10 minutes.

[0056] Experimental results demonstrate that the hydrogel of this invention possesses fluorescence quenching properties, and these properties are modulated by silver ions and cysteine, exhibiting a fluorescence switching response. Therefore, the hydrogel of this invention can be used to detect silver ions and cysteine, and has the potential to be developed into a visual, portable sensor for the rapid detection of silver ions and cysteine.

[0057] In summary, this invention successfully constructed a guanosine supramolecular hydrogel with excellent stability under metal ion-free conditions. This hydrogel exhibits excellent stability for at least six months, overcoming the problem of metal ion-dependent gelation in existing guanosine hydrogels. Test results show that the metal-ion-free guanosine supramolecular hydrogel of this invention, with its loosely porous ellipsoidal structure formed by π-π stacking, possesses good self-healing properties, shear-thinning characteristics, and injectability, showing promising potential in the medical field. It also exhibits a fluorescent switching response to silver ions and cysteine, making it applicable to portable visualization detection of silver ions or cysteine.

Claims

1. A guanosine supramolecular hydrogel, characterized in that: A hydrogel prepared from 8-hydroxyguanosine or 8-aminoguanosine, boric acid, and water under a weakly alkaline environment with a pH of 7.5-8; the ratio of 8-hydroxyguanosine or 8-aminoguanosine, boric acid, and water is (0.025~0.1) mmol:(0.0125~0.1) mmol:1000 μL; the weakly alkaline environment with a pH of 7.5-8 is adjusted by adding a weak base that does not contain metal cations; the weak base that does not contain metal cations is tris(hydroxymethyl)aminomethane.

2. The guanosine supramolecular hydrogel according to claim 1, characterized in that: The ratio of 8-hydroxyguanosine or 8-aminoguanosine, boric acid and water is 0.1 mmol: 0.05 mmol: 1000 μL.

3. The guanosine supramolecular hydrogel according to claim 1 or 2, characterized in that: The molar ratio of the tris(hydroxymethyl)aminomethane to boric acid is 1:

1.

4. The guanosine supramolecular hydrogel according to any one of claims 1 to 2, characterized in that: The water is deionized water.

5. The guanosine supramolecular hydrogel according to any one of claims 1 to 2, characterized in that: Prepare according to the following steps: Add 8-hydroxyguanosine or 8-aminoguanosine to water, dissolve, then add boric acid and a weak base that does not contain metal cations, dissolve, mix, heat, and cool to room temperature to obtain guanosine supramolecular hydrogel.

6. The guanosine supramolecular hydrogel according to claim 5, characterized in that: The dissolution process described herein is performed by heating.

7. A method for preparing the guanosine supramolecular hydrogel according to any one of claims 1 to 6, characterized in that: Add 8-hydroxyguanosine or 8-aminoguanosine to water, dissolve, then add boric acid and a weak base that does not contain metal cations, dissolve, mix well, heat, and cool to room temperature.

8. Use of the guanosine supramolecular hydrogel according to any one of claims 1 to 6 in the preparation of semiconductor materials.

9. Use of the guanosine supramolecular hydrogel according to any one of claims 1 to 6 in the detection of metal ions or cysteine.

10. The use of the guanosine supramolecular hydrogel according to claim 9, characterized in that: The metal ions include potassium ions, sodium ions, and silver ions.

11. Use of the guanosine supramolecular hydrogel according to any one of claims 1 to 6 as a carrier for encapsulating proteins.

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