Ultrasonic responsive antibacterial hydrogel as well as preparation method and application thereof

Abstract

The invention discloses ultrasonic responsive antibacterial hydrogel as well as a preparation method and application thereof. The ultrasonic responsive antibacterial hydrogel is prepared from the following raw materials: polyvinyl alcohol, agarose, barium titanate nanoparticles and water, the mass ratio of the polyvinyl alcohol to the agarose to the barium titanate nanoparticles to the water is 1: (0.25-4): (0.1875-0.75): (4-5). The hydrogel material disclosed by the invention not only can provide a moist environment required by a wound, but also can generate active oxygen under the ultrasonic action, so that wound healing is promoted, infection is prevented, and the rehabilitation process is accelerated.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogels, and in particular to an ultrasound-responsive antibacterial hydrogel and a preparation method and application thereof. Background Art

[0002] The skin, the first protective barrier between the human body and the external environment, is of great significance in preventing microbial invasion. Once the human skin is damaged, its integrity and biological functions will be disturbed, which can easily lead to chronic wound infection. To solve this problem, researchers have added a variety of antimicrobial agents to wound dressings to give the dressings bactericidal capabilities. Although antibiotics encapsulated in dressings are often effective in preventing bacterial infections, there are some unavoidable defects, such as difficulty in controlling drug release, cytotoxicity, and drug resistance caused by excessive use of antibiotics. Therefore, it is particularly important to develop a new, targeted and synergistic chronic wound healing strategy. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings of the prior art and provide an ultrasound-responsive antibacterial hydrogel and its preparation method and application. The present invention combines agarose, polyvinyl alcohol and barium titanate nanoparticles together to prepare a new hydrogel material with ultrasound responsiveness and antibacterial properties. This hydrogel material can not only provide a moist environment required by the wound, but also generate active oxygen under the action of ultrasound, promote wound healing, prevent infection, and accelerate the recovery process.

[0004] To achieve the above purpose, the technical solution designed by the present invention is as follows:

[0005] The invention provides an ultrasound-responsive antibacterial hydrogel. The raw materials of the hydrogel include polyvinyl alcohol, agarose, barium titanate nanoparticles and water. The mass ratio of polyvinyl alcohol, agarose, barium titanate nanoparticles and water is 1:0.25-4:0.1875-0.75:4-5.

[0006] Furthermore, the mass ratio of the polyvinyl alcohol, agarose, barium titanate nanoparticles and water is 1:3:0.375:4.

[0007] Furthermore, the raw materials of the barium titanate nanoparticles include barium titanate nanoparticles to be surface-modified and phospholipid-polyethylene glycol, and the mass ratio of the barium titanate nanoparticles to be surface-modified to the phospholipid-polyethylene glycol is 1:0.4-0.6;

[0008] The raw materials of the barium titanate nanoparticles to be modified on the surface include barium nitrate, sodium hydroxide, tetrabutyl titanate and oleic acid, and the molar ratio of barium nitrate, sodium hydroxide, tetrabutyl titanate and oleic acid is 1:10-13:1-2:8-10.

[0009] Furthermore, the mass ratio of the barium titanate nanoparticles to be modified on the surface to the phospholipid-polyethylene glycol is 1:0.5;

[0010] The molar ratio of barium nitrate, sodium hydroxide, tetrabutyl titanate and oleic acid is 1:12.5:1:8.

[0011] The present invention also provides a method for preparing the ultrasound-responsive antibacterial hydrogel, comprising the following steps:

[0012] (1) Weigh polyvinyl alcohol, agarose, barium titanate nanoparticles and water according to the above mass ratio and set aside;

[0013] (2) Dividing water into two parts, dissolving polyvinyl alcohol in one part of the water, and performing an oil bath to obtain a hydrogel precursor solution A, and dissolving agarose in the other part of the water, and performing an oil bath to obtain a hydrogel precursor solution B;

[0014] (3) The hydrogel precursor solution A and the hydrogel precursor solution B are mixed with barium titanate nanoparticles, stirred and added into a culture dish, and then placed to obtain an ultrasound-responsive antibacterial hydrogel.

[0015] Furthermore, in step (1), the method for preparing barium titanate nanoparticles comprises the following steps:

[0016] S1. Weigh raw materials according to the molar ratio of barium nitrate, sodium hydroxide, tetrabutyl titanate and oleic acid of 1:12.5:1:8, dissolve barium nitrate in deionized water to obtain a barium nitrate solution, dissolve sodium hydroxide in deionized water to obtain a sodium hydroxide solution, dissolve tetrabutyl titanate in a 1-butanol solution to obtain a tetrabutyl titanate solution, and dissolve oleic acid in a 1-butanol solution to obtain an oleic acid solution;

[0017] S2, adding barium nitrate solution, sodium hydroxide solution, tetrabutyl titanate solution and oleic acid solution into a reaction kettle in sequence and heating for reaction;

[0018] S3, cooling and centrifuging to obtain a precipitate, washing the precipitate three times, and dispersing it in n-hexane to obtain barium titanate nanoparticles with surfaces to be modified;

[0019] S4, weighing barium titanate nanoparticles to be modified on the surface and phospholipid-polyethylene glycol, dissolving the barium titanate nanoparticles to be modified on the surface and phospholipid-polyethylene glycol in tetrahydrofuran, and performing ultrasonic dispersion;

[0020] S5, adding water, ultrasonicating, centrifuging to obtain a precipitate;

[0021] S6. Repeat step S5 three times to obtain barium titanate nanoparticles.

[0022] Furthermore, in step S2, the heating reaction conditions are 120-135° C., 16-18 h;

[0023] In step S3, the centrifugation condition is 8000 rpm, 5 min, and the precipitate is washed with ethanol;

[0024] In the step S4, the mass ratio of the barium titanate nanoparticles to be modified on the surface to the phospholipid-polyethylene glycol is 1:0.5;

[0025] In the step S5, ultrasound was performed for 5 minutes and the centrifugal conditions were 8000 rpm for 5 minutes.

[0026] Furthermore, in step (2), the concentration of polyvinyl alcohol in hydrogel precursor solution A is 80-120 mg / mL, the concentration of agarose in hydrogel precursor solution B is 80-120 mg / mL, and the oil bath conditions are 100-120° C. for 1-3 h;

[0027] In the step (3), the stirring conditions are 100° C., 1 h, and the mixture is allowed to stand for 10 to 12 h.

[0028] Furthermore, in the hydrogel precursor solution A, the concentration of polyvinyl alcohol is 100 mg / mL, and in the hydrogel precursor solution B, the concentration of agarose is 100 mg / mL.

[0029] The present invention also provides an application of the ultrasound-responsive antibacterial hydrogel in inhibiting bacterial growth.

[0030] The present invention also provides an application of the ultrasound-responsive antibacterial hydrogel in preparing a product with antibacterial effect.

[0031] Principle of the present invention:

[0032] 1. In terms of wound healing, the relationship between infected skin wounds and the skin's inherent endogenous electric field is widely considered to be an important regulator in the process of cell and tissue repair. During skin injury and infection, a series of complex biopotential changes occur in the body, including the formation of molecules and cell organizations, which generate internal electric fields. Studies have shown that this bioelectric field can promote cell migration and the secretion of growth factors, thereby accelerating wound healing. Barium titanate, as a typical piezoelectric semiconductor material, can immediately generate an internal electric field and surface charge, i.e., the piezoelectric effect, when subjected to external mechanical stress, such as the mechanical force generated by ultrasound. These charges can react with water molecules in the environment to generate reactive oxygen. Because reactive oxygen has antibacterial and anti-inflammatory effects, it can further inhibit infection and promote the wound healing process.

[0033] 2. As a soft material with high water content and similar to biological tissue, hydrogel is widely studied and applied due to its unique physical properties and biocompatibility. Agarose is a natural polysaccharide whose aqueous solution can be dissolved when heated to above 90°C, and can form a hydrogel with good flexibility when cooled to 35-40°C. Agarose hydrogel is favored for its excellent biocompatibility and flexibility, but its mechanical properties are relatively poor, which limits its widespread use in certain application scenarios. Polyvinyl alcohol, as a water-soluble polymer material, is known for its excellent mechanical properties, especially high toughness. When polyvinyl alcohol forms hydrogels with water as the medium, these hydrogels exhibit excellent mechanical properties. By mixing agarose and polyvinyl alcohol in a certain proportion, a composite hydrogel with both good flexibility and excellent mechanical properties can be prepared. In addition, hydrogels show great potential in the medical field, especially in the preparation of wound dressings, due to their high water absorption, biodegradability and unique porous structure. Combining the piezoelectric antibacterial properties of barium titanate with the above hydrogel can produce a new type of material with ultrasonic responsiveness and antibacterial properties. This material can not only provide the moist environment required by the wound, but also generate active oxygen under the action of ultrasound, promote wound healing, prevent infection, and accelerate the recovery process.

[0034] Beneficial effects of the present invention:

[0035] The present invention provides a novel hydrogel combining agarose, polyvinyl alcohol and barium titanate nanoparticles, which has excellent mechanical properties and antibacterial effects while maintaining good biocompatibility. In an in vitro antibacterial experiment, under the action of ultrasound, the hydrogel of the present invention rapidly generates active oxygen through the piezoelectric effect of barium titanate nanoparticles, showing excellent antibacterial activity, and is expected to be widely used in the medical field. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a transmission electron microscope image of barium titanate nanoparticles;

[0037] Figure 2 is the X-ray diffraction pattern of barium titanate nanoparticles;

[0038] Figure 3 This is a scanning electron micrograph of ultrasound-responsive antibacterial hydrogel;

[0039] Figure 4 This is the X-ray energy spectrum elemental image analysis diagram of ultrasound-responsive antibacterial hydrogel;

[0040] Figure 5 This is the electron spin resonance spectrum of ultrasound-responsive antibacterial hydrogel;

[0041] In the figure, Figure a is superoxide anion (O 2- ), and Figure b is the result diagram of hydroxyl radical (·OH);

[0042] Figure 6 This is a diagram showing the ultrasonic antibacterial effect of the ultrasound-responsive antibacterial hydrogel;

[0043] In the figure, Figure a is a plate map of Staphylococcus aureus, and Figure b is a survival rate result map of Staphylococcus aureus. DETAILED DESCRIPTION

[0044] The present invention is further described in detail below in conjunction with specific embodiments so that those skilled in the art can understand.

[0045] Example 1

[0046] Preparation of Barium Titanate Nanoparticles

[0047] (1) 1 mmol of barium nitrate (261 mg) was dissolved in 5 mL of deionized water to obtain a barium nitrate solution, 12.5 mmol of sodium hydroxide (500 mg) was dissolved in 5 mL of deionized water to obtain a sodium hydroxide solution, 1 mmol of tetrabutyl titanate (340 μL) was dissolved in 5 mL of 1-butanol solution to obtain a tetrabutyl titanate solution, and 8 mmol of oleic acid (2.5 mL) was dissolved in 5 mL of 1-butanol solution to obtain an oleic acid solution.

[0048] (2) Add barium nitrate solution, sodium hydroxide solution, tetrabutyl titanate solution and oleic acid solution into a hydrothermal reactor in sequence and heat to 135° C. for 18 hours.

[0049] (3) After cooling naturally to room temperature, centrifuge at 8000 rpm for 5 min to obtain a precipitate, wash the precipitate three times with ethanol, and finally disperse it in n-hexane to obtain barium titanate nanoparticles with surfaces to be modified.

[0050] (4) 50 mg of the barium titanate nanoparticles to be surface modified and 25 mg of phospholipid-polyethylene glycol with a molecular weight of 2000 were dissolved in 200 μL of tetrahydrofuran and dispersed by ultrasonication.

[0051] (5) Add 4 mL of water, sonicate for 5 min, and centrifuge at 8000 rpm for 5 min to obtain a precipitate.

[0052] (6) Repeat step (5) three times to obtain 75 mg of water-soluble barium titanate nanoparticles, i.e., barium titanate nanoparticles.

[0053] Example 2

[0054] Characterization of Barium Titanate Nanoparticles

[0055] This example studies the structure and morphology of the barium titanate nanoparticles prepared in Example 1. The barium titanate nanoparticles were analyzed by transmission electron microscopy. Figure 1 As shown, the particle size distribution of barium titanate nanoparticles is relatively uniform.

[0056] X-ray diffraction analysis of barium titanate nanoparticles showed the following results: Figure 2 As shown, the characteristics of the barium titanate nanoparticles match those of the tetragonal system, so the barium titanate nanoparticles prepared in Example 1 are of the tetragonal system.

[0057] Example 3

[0058] A method for preparing an ultrasound-responsive antibacterial hydrogel, the specific preparation method is:

[0059] (1) Weigh 200 mg of polyvinyl alcohol, 600 mg of agarose and 75 mg of the barium titanate nanoparticles prepared in Example 1.

[0060] (2) Dissolve polyvinyl alcohol in 2 mL of water and incubate in an oil bath at 100° C. for 3 h until the polyvinyl alcohol is completely dissolved to obtain a hydrogel precursor solution A. Dissolve agarose in 6 mL of water and incubate in an oil bath at 120° C. for 1 h until the agarose is completely hydrolyzed to obtain a hydrogel precursor solution B.

[0061] (3) The hydrogel precursor solution A and the hydrogel precursor solution B were mixed with barium titanate nanoparticles, stirred at 100° C. for 1 h, added to a culture dish after stirring, and left overnight (10 to 12 h) to obtain an ultrasound-responsive antibacterial hydrogel.

[0062] Example 4

[0063] Structural morphology characterization of ultrasound-responsive antibacterial hydrogel

[0064] 1. This example studies the structure and morphology of the ultrasound-responsive antibacterial hydrogel prepared in Example 3. The ultrasound-responsive antibacterial hydrogel was analyzed by scanning electron microscopy. The results are as follows: Figure 3 As shown, the ultrasound-responsive antibacterial hydrogel has a good porous structure.

[0065] 2. X-ray energy spectrum elemental image analysis of ultrasound-responsive antibacterial hydrogel, the results are as follows Figure 4 As shown, Ba and Ti are uniformly dispersed in the hydrogel network.

[0066] 3. The piezoelectric properties of ultrasound-responsive antibacterial hydrogels were studied, and electron spin resonance analysis was performed on ultrasound-responsive antibacterial hydrogels. The results are as follows: Figure 5 As shown in Figure 2, superoxide anions (O 2 -) and hydroxyl radical (·OH) signals, demonstrating that the ultrasound-responsive antibacterial hydrogel has a significant piezoelectric effect under ultrasound.

[0067] Example 5

[0068] Application of ultrasound-responsive antibacterial hydrogels

[0069] In this example, the antibacterial properties of the ultrasound-responsive antibacterial hydrogel prepared in Example 3 are studied.

[0070] (1) 1 mL of ultrasound-responsive antibacterial hydrogel was applied to the surface of a 24-well cell plate, and 10 μL of the prepared Staphylococcus aureus suspension (10 6 The ultrasound-responsive antibacterial hydrogel surface was added to the 24-well cell plate. At the same time, the 24-well cell plate without ultrasound-responsive antibacterial hydrogel was used as a control.

[0071] (2) After 10 minutes of ultrasonic irradiation, the 24-well plate was placed in a 37°C incubator for 2 hours. Then, the bacteria in the 24-well plate were suspended and separated from the surface with 1 mL of sterile PBS, and diluted to an appropriate concentration for coating. At the same time, a control was used that was not subjected to ultrasonic irradiation.

[0072] (3) After 18 h of incubation, bacterial survival was determined by counting the number of bacterial colony-forming units on the solid agar plate. Each group was repeated three times.

[0073] Figure 6 This is a diagram showing the in vitro ultrasound-triggered piezoelectric catalytic antibacterial treatment effect of ultrasound-responsive antibacterial hydrogel on Staphylococcus aureus. Figure 6 a is a plate image of Staphylococcus aureus. It can be seen from the figure that after 10 minutes of ultrasound, there is almost no colony formation on the agar plate on the ultrasound-responsive antibacterial hydrogel group. Figure 6 b is the survival rate of Staphylococcus aureus. In the presence of ultrasound-responsive antibacterial hydrogel, the survival rate of Staphylococcus aureus dropped sharply after ultrasound treatment, indicating that ultrasound-responsive antibacterial hydrogel has good bactericidal properties under ultrasound.

[0074] Although the above embodiments have been described in detail, they are only a part of the embodiments of the present invention, not all of them. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all belong to the protection scope of the present invention.

Claims

1. An ultrasound-responsive antibacterial hydrogel, characterized in that: The raw materials of the hydrogel include polyvinyl alcohol, agarose, barium titanate nanoparticles and water; the mass ratio of polyvinyl alcohol, agarose, barium titanate nanoparticles and water is 1:0.25-4:0.1875-0.75:4-5.

2. The ultrasound-responsive antibacterial hydrogel according to claim 1, characterized in that: The mass ratio of the polyvinyl alcohol, agarose, barium titanate nanoparticles and water is 1:3:0.375:

4.

3. The ultrasound-responsive antibacterial hydrogel according to claim 2, characterized in that: The raw materials of the barium titanate nanoparticles include barium titanate nanoparticles to be surface-modified and phospholipid-polyethylene glycol, and the mass ratio of the barium titanate nanoparticles to be surface-modified to the phospholipid-polyethylene glycol is 1:0.4-0.6; The raw materials of the barium titanate nanoparticles to be modified on the surface include barium nitrate, sodium hydroxide, tetrabutyl titanate and oleic acid, and the molar ratio of barium nitrate, sodium hydroxide, tetrabutyl titanate and oleic acid is 1:10-13:1-2:8-10.

4. The ultrasound-responsive antibacterial hydrogel according to claim 3, characterized in that: The mass ratio of the barium titanate nanoparticles to be modified on the surface to the phospholipid-polyethylene glycol is 1:0.5; The molar ratio of barium nitrate, sodium hydroxide, tetrabutyl titanate and oleic acid is 1:12.5:1:

8.

5. A method for preparing the ultrasound-responsive antibacterial hydrogel according to any one of claims 1 to 4, characterized in that: The following steps are involved: (1) weighing polyvinyl alcohol, agarose, barium titanate nanoparticles and water according to the above mass ratio and setting aside; (2) Dividing water into two parts, dissolving polyvinyl alcohol in one part of the water, and performing an oil bath to obtain a hydrogel precursor solution A, and dissolving agarose in the other part of the water, and performing an oil bath to obtain a hydrogel precursor solution B; (3) The hydrogel precursor solution A and the hydrogel precursor solution B are mixed with barium titanate nanoparticles, stirred and added into a culture dish, and then placed to obtain an ultrasound-responsive antibacterial hydrogel.

6. The preparation method according to claim 5, characterized in that: In the step (1), the method for preparing barium titanate nanoparticles comprises the following steps: S1. Weigh raw materials according to the molar ratio of barium nitrate, sodium hydroxide, tetrabutyl titanate and oleic acid of 1:12.5:1:8, dissolve barium nitrate in deionized water to obtain a barium nitrate solution, dissolve sodium hydroxide in deionized water to obtain a sodium hydroxide solution, dissolve tetrabutyl titanate in a 1-butanol solution to obtain a tetrabutyl titanate solution, and dissolve oleic acid in a 1-butanol solution to obtain an oleic acid solution; S2, adding barium nitrate solution, sodium hydroxide solution, tetrabutyl titanate solution and oleic acid solution into a reaction kettle in sequence and heating for reaction; S3, cooling and centrifuging to obtain a precipitate, washing the precipitate three times, and dispersing it in n-hexane to obtain barium titanate nanoparticles with surfaces to be modified; S4, weighing barium titanate nanoparticles to be modified on the surface and phospholipid-polyethylene glycol, dissolving the barium titanate nanoparticles to be modified on the surface and phospholipid-polyethylene glycol in tetrahydrofuran, and performing ultrasonic dispersion; S5, adding water, ultrasonicating, centrifuging to obtain a precipitate; S6. Repeat step S5 three times to obtain barium titanate nanoparticles.

7. The preparation method according to claim 6, characterized in that: In step S2, the heating reaction conditions are 120-135° C. for 16-18 hours; In step S3, the centrifugation condition is 8000 rpm, 5 min, and the precipitate is washed with ethanol; In the step S4, the mass ratio of the barium titanate nanoparticles to be modified on the surface to the phospholipid-polyethylene glycol is 1:0.5; In the step S5, ultrasound was performed for 5 minutes and the centrifugal conditions were 8000 rpm for 5 minutes.

8. The preparation method according to claim 5, characterized in that: In the step (2), the concentration of polyvinyl alcohol in the hydrogel precursor solution A is 80-120 mg / mL, the concentration of agarose in the hydrogel precursor solution B is 80-120 mg / mL, and the oil bath conditions are 100-120° C. for 1-3 hours; In the step (3), the stirring conditions are 100° C., 1 h, and the mixture is allowed to stand for 10 to 12 h.

9. The preparation method according to claim 8, characterized in that: In the hydrogel precursor solution A, the concentration of polyvinyl alcohol is 100 mg / mL, and in the hydrogel precursor solution B, the concentration of agarose is 100 mg / mL.

10. Use of the ultrasound-responsive antibacterial hydrogel according to any one of claims 1 to 4 in the preparation of a product having antibacterial properties.

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