Preparation method of mangiferin-based photosensitive hydrogel and product of mangiferin-based photosensitive hydrogel

Abstract

According to the preparation method of the mangiferin-based photosensitive hydrogel and the product of the mangiferin-based photosensitive hydrogel, mangiferin serves as a carrier, the pH value of the environment is reflected in real time through the intensity change of a fluorescence signal, and the mangiferin-based photosensitive hydrogel has the advantages of being non-invasive, high in sensitivity, visual and the like; the antibacterial activity of the hydrogel is enhanced through the photosensitizer, and the hydrogel is suitable for non-invasive antibacterial treatment; the hydrogel is self-assembled by controlling the pH value, the state of the hydrogel can be adjusted according to needs, and the hydrogel has high responsiveness and controllability.

Description

Technical Field

[0001] The present invention belongs to the technical field of biomedical materials, and more specifically, relates to a preparation method of a mangiferin-based photosensitive hydrogel and its product. Background Art

[0002] A hydrogel is a three-dimensional cross-linked material composed of a hydrophilic polymer network, which can absorb and retain a large amount of water while maintaining a solid structure without dissolution. Hydrogels can load bioactive components and are widely used in the fields of food, medicine, and daily chemicals.

[0003] Hydrogels are classified into natural hydrogels and synthetic hydrogels according to their sources. Natural hydrogel materials mainly come from polysaccharides, such as sodium alginate, hyaluronic acid, and chitosan; they can also come from proteins, such as collagen, gelatin, and fibrin. Natural hydrogels have good biocompatibility, high moisture retention performance, and are biodegradable; however, they have low mechanical strength and are easily enzymatically degraded. Synthetic hydrogels mainly come from polymers, such as polyacrylamide, polyethylene glycol, and polyvinyl alcohol, which have adjustable mechanical properties and high stability; however, their biocompatibility is poor and it is inconvenient to remove them after use.

[0004] Regardless of whether it is a natural hydrogel or a synthetic hydrogel, hydrogels mainly play a carrier function and all need to be additionally loaded with functional materials to enhance the application potential of the gel system, such as antibacterial agents, etc. Due to the limited loading capacity of hydrogels, the role of functional materials is restricted.

[0005] Therefore, it is of great value to develop a hydrogel with high compatibility, high strength, high efficacy, and convenient use. Summary of the Invention

[0006] In order to solve the above technical problems, in the first aspect of the present invention, a preparation method of a mangiferin-based photosensitive hydrogel is provided, including the following steps:

[0007] Step S1, preparing a mangiferin-based polyphenol solution: Weigh mangiferin, add mangiferin to an alkaline solution and shake to dissolve to obtain solution A;

[0008] Step S2, preparing a mangiferin-based polyphenol photosensitive antibacterial solution: Weigh a photosensitive antibacterial agent, add the photosensitive antibacterial agent to solution A and shake to dissolve to obtain solution B;

[0009] Step S3, inducing the assembly of a mangiferin-based polyphenol photosensitive antibacterial hydrogel by pH adjustment: Use an acid solution to adjust the pH value of solution B to induce the assembly of a mangiferin-based photosensitive hydrogel.

[0010] As a preferred technical solution, the photosensitive antibacterial agent in step S2 is one or more of berberine, aloe-emodin, and curcumin.

[0011] Mangiferin is a natural polyphenolic compound belonging to xanthones and has biological activities such as anti-inflammatory, antiviral, and anti-tumor. Under the action of appropriate acidity and alkalinity, mangiferin forms a carrier-free self-gel system through non-covalent interactions, with good mechanical strength, renewability, and biocompatibility. The mangiferin-based hydrogel can also load additional antibacterial bioactive components, resulting in good antibacterial effects of the mangiferin-based hydrogel.

[0012] Aloe-emodin and curcumin belong to polyphenolic compounds, and berberine belongs to natural isoquinoline alkaloids. When excited at a specific wavelength, all three can enter the high-energy state and react with oxygen through energy transfer or electron transfer to generate reactive oxygen species (ROS) such as singlet oxygen ( 1 O2), superoxide anion (O2 - ), and hydroxyl radical (·OH). The reactive oxygen species damage the bacterial cell membrane, proteins, lipids, and DNA through oxidative damage, leading to bacterial death and high-efficiency antibacterial activity.

[0013] As a preferred technical solution, the pH value of solution B in step S3 is 6 to 9.5.

[0014] The acidity and alkalinity affect the charge states of substances such as mangiferin polyphenol, aloe-emodin, curcumin, and berberine. When the pH value is 6 to 9.5, the interaction forces such as electrostatic interaction and hydrogen bond are enhanced, enabling the formation of a three-dimensional network structure between molecules, thereby self-assembling to form a hydrogel.

[0015] As a preferred technical solution, the alkaline solution in step S1 is a sodium hydroxide solution with a concentration of 0.1 mol / L to 0.5 mol / L.

[0016] As a preferred technical solution, the concentration of mangiferin in solution A in step S1 is 15 g / L to 30 g / L.

[0017] As a preferred technical solution, the mass ratio of the photosensitive antibacterial agent to mangiferin in step S2 is 1:(1 to 2).

[0018] As a preferred technical solution, the acid solution in step S3 is hydrochloric acid with a concentration of 0.1 mol / L to 2 mol / L.

[0019] In the second aspect of the present invention, a mangiferin-based photosensitive hydrogel is provided, and the mangiferin-based photosensitive hydrogel is prepared by the aforementioned preparation method.

[0020] In the third aspect of the present invention, the application of the mangiferin-based photosensitive hydrogel in dressings is provided.

[0021] In the fourth aspect of the present invention, the application of the mangiferin-based photosensitive hydrogel in photosensitive antibacterial is provided.

[0022] When the mangiferin-based photosensitive hydrogel is used as a dressing to care for wounds, the antibacterial effect can be enhanced by light irradiation.

[0023] In the fifth aspect of the present invention, there is provided the use of the mangiferin-based photosensitive hydrogel as a pH indicator.

[0024] Mangiferin is a xanthone polyphenol compound. It has a large Stokes shift and can form a natural aggregation-induced emission effect. It can emit fluorescence under ultraviolet light and has the potential to be used as a fluorescent pH indicator. Multiple hydroxyl groups in its molecule can be protonated or deprotonated when the pH changes, altering the electron distribution and aggregation morphology, thereby affecting the fluorescence behavior.

[0025] Aloe-emodin belongs to an anthraquinone compound and contains a conjugated anthraquinone structure. This rigid planar system has fluorescence characteristics, is easy to absorb ultraviolet light and emit fluorescence, and has the potential to be used as a fluorescent pH indicator. Multiple hydroxyl groups in its molecule can be protonated or deprotonated when the pH changes, altering the electron distribution, thereby affecting the fluorescence behavior.

[0026] Curcumin contains a conjugated structure in which two o-methoxyphenol groups are bridged by an α,β-unsaturated β-diketone. This rigid conjugated system endows it with fluorescence characteristics. The phenolic hydroxyl group and β-diketone group in the molecule can be protonated / deprotonated when the pH changes, significantly altering the electron distribution and conjugated length, thereby affecting the fluorescence behavior.

[0027] The rigid isoquinoline ring and conjugated double bond system of berberine endow it with fluorescence characteristics. The hydroxyl group and methoxy group in the molecule can be protonated / deprotonated when the pH changes, altering the electron distribution and the intramolecular charge transfer effect, thereby regulating the fluorescence intensity or emission wavelength.

[0028] When the mangiferin-based photosensitive hydrogel is used as a dressing to care for wounds, the change in the pH value of the dressing can be detected by fluorescence excitation, reflecting the degree of microbial contamination of the wound.

[0029] By the above technical solutions, the present invention has the following technical effects:

[0030] (1) Using mangiferin with antibacterial activity as a carrier, it has high biocompatibility.

[0031] (2) It can reflect the environmental pH value in real time through the change in the intensity of the fluorescence signal, and has the advantages of non-invasiveness, high sensitivity, visualization, etc.

[0032] (3) The antibacterial activity of the hydrogel is enhanced by the photosensitizer, which is suitable for non-invasive antibacterial treatment.

[0033] (4) The self-assembled hydrogel is controlled by pH, and the hydrogel state can be adjusted as needed, with high responsiveness and controllability. For example, the pH can be adjusted to make the hydrogel in a solution state for easy removal. Description of the Drawings

[0034] Figure 1 The appearance morphologies of the hydrogels prepared in Examples 1 to 3, from left to right are Examples 1 to 3 in sequence;

[0035] Figure 2 The scanning electron microscope images of the hydrogels prepared in Examples 1 to 3, from left to right are Examples 1 to 3 in sequence;

[0036] Figure 3 The viscosity and rheological properties of the hydrogel at different concentrations of mangiferin and curcumin; Man represents mangiferin, and Cur represents curcumin; (Note: In the left figure, the abscissa Shear Rate is the shear rate, and the ordinate Viscosity is the apparent viscosity; in the right figure, the abscissa Frequency is the scanning frequency, and the ordinates G' and G″ are the storage modulus and loss modulus respectively);

[0037] Figure 4 The state diagrams of the hydrogel of Example 3 under different pH conditions; the values in the figure represent the corresponding pH;

[0038] Figure 5 The relationship diagram between the pH value and fluorescence intensity of the hydrogel prepared in Example 2; (Note: F 535 is the fluorescence intensity measured at an excitation wavelength of 535 nm).

[0039] Figure 6 The photodynamic antibacterial effect diagrams of the hydrogels prepared in Examples 1 to 3 and the samples A to D of the test examples; Man represents mangiferin, Cur represents curcumin; BBR represents berberine, and AE represents aloe-emodin. (Note: Dark is the control group treated under dark light, and Light is the experimental group treated with white light irradiation; Viable Counts is the number of viable bacteria) Detailed Embodiments

[0040] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0041] Example 1

[0042] Step S1, Prepare the mangiferin-based polyphenol solution: Weigh mangiferin, add the mangiferin to an alkali solution and dissolve it by shaking to obtain solution A; the alkali solution is a 0.25 mol / L sodium hydroxide solution; the concentration of mangiferin in the alkali solution is 22 g / L.

[0043] Step S2, Prepare the mangiferin-based polyphenol photosensitizing antibacterial solution: Weigh the photosensitizing antibacterial agent, add the photosensitizing antibacterial agent to solution A and dissolve it by shaking to obtain solution B; the mass ratio of the photosensitizing antibacterial agent to mangiferin is 1:2; the photosensitizing antibacterial agent is berberine.

[0044] Step S3, Induce the assembly of the mangiferin-based polyphenol photosensitizing antibacterial hydrogel by adjusting the pH value: Use an acid solution to adjust the pH value of solution B to induce the assembly of the mangiferin-based polyphenol photosensitizing antibacterial hydrogel; the pH value of solution B is 9.5; the acid solution is a 0.5 mol / L hydrochloric acid solution.

[0045] Example 2:

[0046] Step S1, Prepare the mangiferin-based polyphenol solution: Weigh mangiferin, add the mangiferin to an alkali solution and dissolve it by shaking to obtain solution A; the alkali solution is a 0.25 mol / L sodium hydroxide solution; the concentration of mangiferin in the alkali solution is 15 g / L.

[0047] Step S2, Prepare the mangiferin-based polyphenol photosensitizing antibacterial solution: Weigh the photosensitizing antibacterial agent, add the photosensitizing antibacterial agent to solution A and dissolve it by shaking to obtain solution B; the mass ratio of the photosensitizing antibacterial agent to mangiferin is 1:1.5; the photosensitizing antibacterial agent is aloe-emodin.

[0048] Step S3, Induce the assembly of the mangiferin-based polyphenol photosensitizing antibacterial hydrogel by adjusting the pH value: Use an acid solution to adjust the pH value of solution B to induce the assembly of the mangiferin-based polyphenol photosensitizing antibacterial hydrogel; the pH value of solution B is 6.0; the acid solution is a 0.1 mol / L hydrochloric acid solution.

[0049] Example 3:

[0050] Step S1, Prepare the mangiferin-based polyphenol solution: Weigh mangiferin, add the mangiferin to an alkali solution and dissolve it by shaking to obtain solution A; the alkali solution is a 0.25 mol / L sodium hydroxide solution; the concentration of mangiferin in the alkali solution is 30.6 g / L.

[0051] Step S2, Prepare the mangiferin-based polyphenol photosensitizing antibacterial solution: Weigh the photosensitizing antibacterial agent, add the photosensitizing antibacterial agent to solution A and dissolve it by shaking to obtain solution B; the mass ratio of the photosensitizing antibacterial agent to mangiferin is 1:1.5; the photosensitizing antibacterial agent is curcumin.

[0052] Step S3, pH-induced assembly of mangiferin-based polyphenol photosensitive antibacterial hydrogel: Use an acid solution to adjust the pH value of Solution B to induce the assembly of mangiferin-based polyphenol photosensitive antibacterial hydrogel; the pH value of Solution B is 7.0; the acid solution is 2 mol / L hydrochloric acid.

[0053] Test Example 1

[0054] Observation of appearance and morphology: Place the hydrogels prepared in Examples 1 to 3 in transparent screw-cap bottles, and confirm the gel state by inversion. Take pictures to record the appearance state of the samples.

[0055] As Figure 1 shown, the hydrogels prepared in Examples 1 to 3 are all in a gel state, have certain spreadability, and no liquid flows down after inversion, showing no fluidity. Due to the different contents of the plant polyphenol composition, there are differences in color.

[0056] Test Example 2

[0057] Scanning electron microscope (SEM): Take an appropriate amount of the hydrogel samples of Examples 1 to 3 and place them in a screw-cap bottle. Pre-freeze them to a solid state at -80 °C, and then freeze-dry them with a freeze-drying device to obtain dehydrated hydrogel samples. Take an appropriate amount of the freeze-dried samples and place them on the SEM sample stage. After sputtering with gold, observe their microstructures under a scanning electron microscope.

[0058] As Figure 2 shown, the scanning electron micrographs of Examples 1 to 3 all show a three-dimensional spatial structure formed by flakes and fibers, presenting the morphology of the gel dry matter. In addition, compared with Examples 1 and 3, the contents of mangiferin and the photodynamic antibacterial agent aloe-emodin in Example 2 are less, and the formed three-dimensional spatial structure is relatively loose.

[0059] Test Example 3

[0060] According to the method of Example 3, prepare hydrogels with different concentrations of mangiferin and curcumin respectively. The test design is shown in the following table:

[0061] Sample Name Mangiferin (%) Curcumin (%) Sample A 3 2 Sample B 1.5 1 Sample C 0.75 0.5 Sample D 0.4 0.3

[0062] Special note: In this test example, % is equivalent to g / 100 ml.

[0063] Rheological properties: Use a HAAKE rheometer to measure the rheological properties of Samples A to D. Select a 60 mm parallel plate with a fixed gap of 1 mm. For dynamic viscoelasticity measurement, at a frequency of 1 Hz, determine the linear viscoelastic region of the emulsion by dynamic amplitude scanning. Measure the viscosity of the samples at a shear rate of 25 °C, 0.1 - 100 s -1 and measure the storage modulus (G') and loss modulus (G″) of the samples at 0.1 - 15 Hz under a strain of 0.5%.

[0064] As Figure 3 shown, the viscosity of Sample D, i.e., the system of 0.4% mangiferin + 0.3% curcumin, is very low, and G″>G' indicates that the sample mainly exhibits viscous behavior, that is, the sample cannot recover its original shape after being stressed and does not have the ability to rebound. While the viscosities of the other three samples are higher, and G'>G″ indicates that the samples mainly exhibit elastic behavior, that is, they can recover a certain original shape after being stressed and have good gel elasticity.

[0065] Test Example 4

[0066] According to the method of Example 3, hydrogels with different pH values were prepared respectively, and the pH values were 3, 4, 5, 6, 7, 8, 9, 9.5, 10, 11, and 12.

[0067] As Figure 4 shown, hydrogels that can be inverted can be self-assembled within the pH range of 6-9.5. When pH<6 or pH>9.5, they are in a liquid state, and when pH<6, mangiferin and curcumin will crystallize and precipitate.

[0068] Test Example 5

[0069] Fluorescence indicator evaluation: 5 mg of the sample prepared in Example 2 was dispersed in 50 mL of phosphate buffer at different pH values (pH 3-9). After mixing evenly, the fluorescence color was observed under an ultraviolet lamp, and the fluorescence intensity was measured with a fluorescence spectrophotometer at an excitation wavelength of 535 nm.

[0070] As Figure 5 shown, the sample shows bright fluorescence under ultraviolet light. The fluorescence is purple-orange at pH 3-5, bright orange at pH 6, and brighter fluorescent green at pH 7-9. The results measured by the fluorescence spectrophotometer show that the fluorescence intensity is weak at pH 3-5, significantly increases at pH 6, further increases at pH 7-9, and slightly increases with the increase of pH. The above results indicate that the change of hydrogel pH can be indicated by the fluorescence intensity.

[0071] Test Example 6

[0072] Antibacterial activity evaluation: The antibacterial properties of the hydrogels of Examples 1-3 and the samples A-D hydrogels of Test Example 2 were detected by the colony counting method, and Escherichia coli was selected as the representative bacterium. First, 50 mg of the hydrogel was placed under ultraviolet light for 1 hour and then placed in a 6-well plate. 0.1 mL of the bacterial suspension (1×10 6 CFU / mL) was dropped on the hydrogel. Then it was irradiated with white light for 30 min, and the control group was placed in the dark. Finally, 2 mL of PBS was added to each well, and 0.1 mL of the mixture was smeared on an agar plate and cultured at 37°C for 24 h. The results are expressed as the number of viable bacteria.

[0073] As Figure 6 shown, the individual mangiferin (Man) has no photodynamic antibacterial effect. After adding the plant antibacterial agents berberine (BBR), aloe-emodin (AE) and curcumin (Cur) to the hydrogel, the hydrogel has good antibacterial effect, and the antibacterial effect is positively correlated with the concentration of the antibacterial agent. The higher the concentration of the antibacterial agent, the better the antibacterial effect.

[0074] The above embodiments are only the preferred embodiments of the present invention, and the scope of protection of the present invention cannot be limited thereby. Any non-substantial changes and substitutions made by those skilled in the art based on the present invention belong to the scope of protection required by the present invention.

Claims

1. A method for preparing a mangiferin-based photosensitive hydrogel, characterized in that: The following steps are involved: Step S1, preparing a mangiferin-based polyphenol solution: weighing mangiferin, adding mangiferin into an alkaline solution and shaking to dissolve the mangiferin, to obtain a solution A; Step S2, preparing a mangiferin-based polyphenol photosensitive antibacterial solution: weighing a photosensitive antibacterial agent, adding the photosensitive antibacterial agent to solution A and shaking to dissolve, to obtain solution B; the photosensitive antibacterial agent is one or more of berberine, aloe-emodin, and curcumin; Step S3, pH-induced assembly of mangiferin-based polyphenol photosensitive antibacterial hydrogel: using an acid solution to adjust the pH value of solution B to induce the assembly of mangiferin-based photosensitive hydrogel; the pH value of solution B is 6 to 9.

5.

2. The preparation method according to claim 1, characterized in that: The acid solution in step S3 is 0.1 mol / L to 2 mol / L hydrochloric acid.

3. The preparation method according to claim 1, characterized in that: The alkaline solution in step S1 is a 0.1 mol / L to 0.5 mol / L sodium hydroxide solution.

4. The preparation method according to claim 3, characterized in that: The concentration of mangiferin in solution A in step S1 is 15 g / L to 30 g / L.

5. The preparation method according to claim 4, characterized in that: The mass ratio of the photosensitive antibacterial agent to mangiferin in step S2 is 1:(1-2).

6. A mangiferin-based photosensitive hydrogel, characterized in that: The mangiferin-based photosensitive hydrogel is prepared by the preparation method according to claim 1.

7. Use of the mangiferin-based photosensitive hydrogel according to claim 6 in dressings.

8. Use of the mangiferin-based photosensitive hydrogel according to claim 6 in photosensitizing antibacterial agents.

9. Use of the mangiferin-based photosensitive hydrogel according to claim 6 in a pH indicator.

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