Preparation method of layered double hydroxide with photo-thermal antibacterial property

Abstract

The invention belongs to the field of preparation of layered double hydroxides, and discloses a preparation method of layered double hydroxides with photo-thermal antibacterial performance, which comprises the following steps: mixing a copper salt aqueous solution and a salt aqueous solution, adding into a sodium hydroxide aqueous solution, stirring and mixing; and standing and aging the mixed solution, centrifugally separating, taking the precipitate, washing, and drying to obtain the copper-based layered double hydroxide. The preparation method and process equipment are simple, nitrogen atmosphere and hydrothermal reaction are not needed, the reaction temperature is low, the synthesis process is easy to control, and the feasibility and repeatability are high. The obtained layered double hydroxide has an excellent photothermal effect, and the temperature can be increased to 75 DEG C from room temperature after the layered double hydroxide is irradiated by 808 nm near-infrared light with the intensity of 2 W / cm < 2 > for 10 min; the antibacterial performance is remarkable, and the antibacterial rate on staphylococcus aureus, escherichia coli and klebsiella pneumoniae can reach 99.9%.

Description

Technical Field

[0001] This invention belongs to the field of layered double hydroxide preparation, and particularly relates to a method for preparing a copper-based layered double hydroxide with photothermal antibacterial properties. Background Technology

[0002] Layered double hydroxides are low-cost biomaterials with a two-dimensional ionic layered structure. They consist of hydrotalcite-like compounds composed of divalent and trivalent metal cations in brucite-like layers, solvent molecules in the interlayers, and anions. Due to their good biocompatibility, low cytotoxicity, high loading capacity, and ability to protect biomolecules within the layers, they can be widely used in biomedical fields such as cell drug delivery and biosensors. However, the application of layered double hydroxides in medical antibacterial materials still has certain limitations.

[0003] To enhance the antibacterial properties of layered double hydroxides, the following methods are commonly used: 1. Doping with antibacterial metal ions. For example, patents CN107897203A and CN107950571A respectively dope copper and silver ions into cobalt-nickel layered double hydroxides. Although the resulting materials possess antibacterial properties, the process is cumbersome, requiring prior combination with antibacterial drugs, as illustrated by patents CN114920274A and CN114768546A. While these existing technologies can impart antibacterial properties to the materials, the preparation processes are complex and costly. Furthermore, antibiotics, while killing pathogens, can also harm the human body, and their widespread use can easily lead to the emergence of drug-resistant bacteria.

[0004] High-temperature protein denaturation is an effective method for killing bacteria, but its practical application is greatly limited. Utilizing inorganic materials with photothermal effects, and with the aid of near-infrared light irradiation, the material converts absorbed light energy into heat energy. High temperatures can disrupt the structural integrity of bacterial cell walls and cell membranes, causing the leakage of vital intracellular substances. Simultaneously, it induces protein denaturation and even DNA damage, interfering with cellular metabolic activities and causing irreversible damage to bacteria. This method, which enhances antibacterial activity through highly efficient photothermal conversion, does not induce drug resistance and possesses broad-spectrum antibacterial properties. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the background art above, and to provide a method for preparing a layered double hydroxide with photothermal antibacterial properties. The prepared layered double hydroxide has excellent photothermal properties and can significantly improve its antibacterial properties while maintaining the biocompatibility of the material.

[0006] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows: A method for preparing a layered double hydroxide with photothermal antibacterial properties includes the following steps: (1) Preparation of copper salt aqueous solution and metal salt solution; (2) Mix the copper salt solution and salt solution obtained in step (1), add them to the sodium hydroxide solution, stir and mix to obtain a mixture; (3) After the mixture obtained in step (2) is allowed to stand and age, it is centrifuged and separated. The precipitate is washed and dried to obtain copper-based crystalline double hydroxide. Copper ions have excellent antibacterial properties, and copper-based crystalline double hydroxide has a photothermal effect, which can further enhance the antibacterial properties.

[0007] Preferably, the copper salt in step (1) is copper nitrate or copper chloride; the metal salt is any one or a combination of aluminum chloride, aluminum nitrate, magnesium chloride, magnesium nitrate, ferric nitrate, ferric chloride, nickel nitrate, and nickel chloride. The metal salts selected in this invention all have antibacterial potential, and the layered double hydroxides obtained by combining with copper salts through precipitation, aging, and other steps have photothermal effects and antibacterial properties.

[0008] Preferably, the concentration of the copper salt aqueous solution in step (1) is 0.1-0.5 mol / L.

[0009] Preferably, the concentration of the metal salt solution in step (1) is 0.1-0.5 mol / L. Preferably, the molar ratio of copper salt to metal salt in step (1) is 1-3:1. Preferably, the concentration of the sodium hydroxide aqueous solution in step (2) is 0.3-0.5 mol / L.

[0010] Preferably, the stirring speed in step (2) is 500-800 rpm and the stirring time is 10-30 min.

[0011] Preferably, the static aging process in step (3) is carried out at 25-60°C for 24-72 hours.

[0012] Preferably, the detergent used in step (3) is deionized water and anhydrous ethanol.

[0013] Preferably, the drying in step (3) is vacuum drying at 30-80°C for more than 24 hours.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The preparation method and equipment used in this invention are simple, do not require a nitrogen atmosphere and can be carried out in an air environment; no hydrothermal reaction is required, the process can be completed in one step, the reaction temperature is low, the synthesis process is easy to control, and the feasibility and reproducibility are high.

[0015] 2. The layered double hydroxide prepared by this invention exhibits excellent photothermal effect at an intensity of 2 W / cm².2 After irradiation with 808nm near-infrared light for 10 minutes, the temperature can rise from room temperature to 75℃.

[0016] 3. The layered double hydroxide prepared by this invention has significant antibacterial properties, with an inhibition rate of up to 99.9% against Staphylococcus aureus, Escherichia coli and Klebsiella pneumoniae. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a SEM image from Embodiment 1 of the present invention; Figure 2 This is the photothermal temperature change curve of Embodiment 1 of the present invention; Figure 3 This is a SEM image from Embodiment 2 of the present invention; Figure 4 This is the antibacterial effect of Embodiment 2 of the present invention against Staphylococcus aureus; Figure 5 This is a SEM image from Embodiment 3 of the present invention; Figure 6 This is the photothermal temperature change curve of Embodiment 3 of the present invention. Detailed Implementation

[0019] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0020] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention.

[0021] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0022] Example 1: A method for preparing a layered double hydroxide with photothermal antibacterial properties, comprising the following steps: (1) Prepare a copper nitrate aqueous solution with a concentration of 0.3 mol / L and an aluminum nitrate aqueous solution with a concentration of 0.1 mol / L, and mix them evenly, wherein the molar ratio of copper salt to aluminum salt is 3:1.

[0023] (2) Add the mixed solution to a sodium hydroxide aqueous solution with a concentration of 0.3 mol / L and stir vigorously at 500 rpm for 10 min.

[0024] (3) The mixture was aged at 25°C for 24 h, centrifuged, and the precipitate was washed repeatedly with deionized water and anhydrous ethanol. It was then vacuum dried at 60°C for 24 h to obtain copper-aluminum layered double hydroxide.

[0025] SEM images of the copper-aluminum layered double hydroxides prepared in this embodiment are shown below. Figure 1 .like Figure 2 As shown, the copper-aluminum layered double hydroxide prepared in this embodiment has a strength of 2 W / cm². 2 After irradiation with 808 nm near-infrared light for 10 minutes, the temperature can rise from room temperature to 75℃. The inhibition rate against Staphylococcus aureus, Escherichia coli, and Klebsiella pneumoniae reaches 99.9%.

[0026] Example 2: A method for preparing a layered double hydroxide with photothermal antibacterial properties, comprising the following steps: (1) Prepare a copper nitrate aqueous solution with a concentration of 0.3 mol / L and a magnesium nitrate aqueous solution with a concentration of 0.3 mol / L, and mix them evenly, wherein the molar ratio of copper salt to magnesium salt is 1:1.

[0027] (2) Add the mixed solution to a 0.5 mol / L sodium hydroxide aqueous solution and stir vigorously at 800 rpm for 30 min.

[0028] (3) The mixture was aged at 25°C for 36 h, centrifuged, and the precipitate was washed multiple times with deionized water and anhydrous ethanol. It was then vacuum dried at 60°C for 24 h to obtain copper-magnesium layered double hydroxide.

[0029] SEM images of the copper-aluminum layered double hydroxides prepared in this embodiment are shown below. Figure 3 The copper-magnesium layered double hydroxide prepared in this embodiment has a strength of 2 W / cm². 2 After irradiation with 808 nm near-infrared light for 10 minutes, the temperature can rise from room temperature to 73.4℃. For example... Figure 4The results show the antibacterial effect of copper-magnesium layered double hydroxides on Staphylococcus aureus under near-infrared light irradiation. Compared with the control groups (a1, a2), the number of surviving colonies in the culture dishes (b1, b2) containing the samples was sharply reduced. The prepared copper-magnesium layered double hydroxides achieved an inhibition rate of 99.9% against Staphylococcus aureus, Escherichia coli, and Klebsiella pneumoniae.

[0030] Example 3: A method for preparing a layered double hydroxide with photothermal antibacterial properties, comprising the following steps: (1) Prepare a 0.2 mol / L copper nitrate aqueous solution and a 0.2 mol / L ferric nitrate aqueous solution, mix them evenly, wherein the molar ratio of copper salt to ferric salt is 2:1.

[0031] (2) Add the mixed solution to a sodium hydroxide aqueous solution with a concentration of 0.4 mol / L and stir vigorously at 800 rpm for 10 min.

[0032] (3) The mixture was aged at 25°C for 24 h, centrifuged, and the precipitate was washed repeatedly with deionized water and anhydrous ethanol. It was then vacuum dried at 60°C for 24 h to obtain copper-iron layered double hydroxide.

[0033] SEM images of the copper-aluminum layered double hydroxides prepared in this embodiment are shown below. Figure 5 .like Figure 6 As shown, the copper-iron layered double hydroxide prepared in this embodiment has a strength of 2 W / cm². 2 After irradiation with 808 nm near-infrared light for 10 minutes, the temperature can rise from room temperature to 72℃. The inhibition rate against Staphylococcus aureus, Escherichia coli, and Klebsiella pneumoniae reaches 99.9%.

Claims

1. A method for preparing a layered double hydroxide having photothermal antibacterial properties, characterized in that: The following steps are involved: (1) Preparing a copper salt aqueous solution and a metal salt solution; (2) mixing the copper salt aqueous solution and the salt water solution obtained in step (1), adding the mixture to the sodium hydroxide aqueous solution, stirring and mixing to obtain a mixed solution; (3) The mixed solution obtained in step (2) is allowed to stand for aging and then centrifuged, and the precipitate is washed and dried to obtain a copper-based layered double hydroxide.

2. The preparation method according to claim 1, characterized in that: The copper salt in step (1) is copper nitrate or copper chloride.

3. The preparation method according to claim 1, characterized in that: The metal salt in step (1) is any one or more of aluminum chloride, aluminum nitrate, magnesium chloride, magnesium nitrate, ferric nitrate, ferric chloride, nickel nitrate and nickel chloride.

4. The preparation method according to claim 1, characterized in that The concentration of the copper salt aqueous solution in step (1) is 0.1-0.5 mol / L, and the concentration of the metal salt solution is 0.1-0.5 mol / L.

5. The preparation method according to claim 1, characterized in that: The molar ratio of the copper salt to the metal salt in step (1) is 1-3:

1.

6. The preparation method according to claim 1, characterized in that The concentration of the sodium hydroxide aqueous solution in step (2) is 0.3-0.5 mol / L.

7. The preparation method according to claim 1, characterized in that The stirring speed in step (2) is 500-800 rpm, and the stirring time is 10-30 min.

8. The preparation method according to claim 1, characterized in that The static aging in step (3) is to stand at 25-60°C for 24-72 hours.

9. The preparation method according to claim 1, characterized in that: The detergents used for washing in step (3) are deionized water and anhydrous ethanol.

10. The preparation method according to any one of claims 1 to 9, characterized in that The drying in step (3) is performed by vacuum drying at 30-80°C for more than 24 hours.

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