Cu2o@zno visible light photocatalytic antibacterial material and preparation method thereof

Abstract

The application discloses a Cu2O@ZnO visible light photocatalytic antibacterial material and a preparation method thereof, and belongs to the technical field of antibacterial material preparation, and the specific steps are as follows: (1) dissolving a zinc salt in deionized water, then adding alkali liquor to adjust the pH to 10-12, and then adding an organic solvent A to uniformly stir under a closed condition to obtain a solution one; (2) adding a copper salt and an organic solvent B to the solution one, performing constant-temperature reaction, and then adding alkali liquor to react, to obtain a solution two; (3) adding ascorbic acid to the solution two, and sequentially performing constant-temperature incubation, centrifugation, washing, freeze-drying and microwave treatment, so that the Cu2O@ZnO visible light photocatalytic antibacterial material is finally obtained. The material has a porous and hollow structure and can be used as a drug carrier; and the coupling of ZnO and Cu2O can improve the utilization rate of solar energy, thereby improving the photocatalytic efficiency and the photocatalytic antibacterial performance of the material.

Description

Technical Field

[0001] The present invention relates to the technical field of antibacterial material preparation, and more particularly to a Cu2O@ZnO visible light photocatalytic antibacterial material and a preparation method thereof. Background Art

[0002] Currently, bacterial infections pose a serious threat to human health and have become the second leading cause of death worldwide after ischemic heart disease. In clinical practice, once a bacterial infection occurs, the most common treatment is the use of antibiotics. However, the misuse of antibiotics accelerates the development of drug-resistant bacteria, leading to a decrease in the efficacy of antibiotics and making common infectious diseases such as sepsis and pneumonia more difficult to treat. Therefore, there is an urgent need to develop new, efficient, rapid, non-toxic and harmless sterilization technologies to overcome problems such as bacterial resistance.

[0003] In recent years, with the advancement of optical technology and the development of photocatalytic materials, photocatalytic sterilization technology has become one of the most promising methods for treating drug-resistant bacterial infections. Compared with traditional sterilization technologies, photocatalytic sterilization has the characteristics of environmental protection, high efficiency, and no drug resistance. Among a large number of photocatalytic materials, zinc oxide has broad prospects in the field of photocatalytic antibacterial due to its excellent chemical stability, photoelectric properties and good biocompatibility. As a photocatalytic antibacterial material, ZnO, when exposed to light with energy equal to or greater than its band gap, the electrons in the valence band (e - ) will be excited to the conduction band and generate corresponding electron holes (h + ). This produces reactive oxygen species (ROS). ROS have extremely strong oxidative activity and can break the chemical bonds of most organic substances. Therefore, they can attack cell membranes, destroying bacterial proteins, lipids, polysaccharides, and other components, ultimately achieving the desired bactericidal effect. However, due to the wide band gap of ZnO, it can only be activated by the ultraviolet region of the solar spectrum, which leads to its low photocatalytic efficiency.

[0004] In order to better utilize the visible light region, which is the main component of solar energy, one of the most promising methods is to use some narrow-bandgap semiconductors as visible light photosensitizers to form coupled semiconductors, thereby achieving higher photocatalytic activity under sunlight. Cu2O is a typical p-type narrow-bandgap semiconductor. Although it can be directly excited by visible light, pure Cu2O is extremely unstable and easily oxidized by humid air, resulting in a short antibacterial effect. However, its suitable bandgap width for capturing solar energy is considered to be the best semiconductor material for sensitizing wide-bandgap semiconductors and improving photocatalytic efficiency. Therefore, coupling ZnO with Cu2O to improve the utilization rate of solar energy and thus improve photocatalytic efficiency has great application prospects.

[0005] Furthermore, most current ZnO and Cu2O have smooth, dense surfaces, resulting in a small specific surface area and low adsorption efficiency. In antimicrobial applications, most antimicrobial agents can only kill bacteria but cannot effectively remove bacterial residues. It is well known that endotoxins in bacterial residues can lead to the production of active substances by bacteria. If these active substances are freely present in wounds, they can attack cells and substances in wound fluid that promote wound healing, thereby affecting the wound healing process.

[0006] Therefore, developing a ZnO and Cu2O composite material with a porous structure, high photocatalytic efficiency and excellent antibacterial effect is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0007] In view of this, the present invention discloses a Cu2O@ZnO visible light photocatalytic antibacterial material and a preparation method thereof. ZnO and Cu2O are coupled by a hydrothermal method to prepare a ZnO and Cu2O composite material with a porous structure, high photocatalytic efficiency and excellent antibacterial effect. This solves the problems in the prior art that ZnO has a wide band gap and can only be activated in the ultraviolet region of the solar spectrum, resulting in low photocatalytic efficiency; although Cu2O can have high photocatalytic efficiency under sunlight, it has poor stability and a short antibacterial effect.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] A method for preparing a Cu2O@ZnO visible light photocatalytic antibacterial material comprises the following steps:

[0010] (1) Dissolve zinc salt in deionized water, then add alkali solution to adjust the pH to 10-12, then slowly add organic solvent A dropwise, and stir uniformly under closed conditions to obtain solution 1;

[0011] (2) adding copper salt and organic solvent B to the solution 1, reacting at a constant temperature, and then adding alkaline solution to react to obtain solution 2;

[0012] (3) Ascorbic acid is added to the second solution, and the solution is incubated at a constant temperature, centrifuged, washed, freeze-dried, and microwave-treated in sequence to obtain the Cu2O@ZnO visible light photocatalytic antibacterial material.

[0013] The beneficial effects achieved by the above technical solution are as follows: the present invention prepares Cu2O@ZnO through a simple one-pot hydrothermal method, wherein the method first uses a hydrothermal method to prepare precursors of ZnO and Cu2O, and then uses ascorbic acid as a reducing agent to reduce the precursors of ZnO and Cu2O by in situ reduction, so that ZnO seed crystals are wrapped on the surface of Cu2O and continue to grow under hydrothermal conditions. After the product is freeze-dried, it is subjected to microwave heat treatment to allow ZnO to continue to grow on the surface of Cu2O until the entire Cu2O surface is covered, thereby obtaining a core-shell structured Cu2O@ZnO photocatalytic antibacterial material; and the finally prepared material combines the characteristics of n-type semiconductor zinc oxide and p-type semiconductor cuprous oxide. In addition, ascorbic acid is a vitamin with high biological safety, thereby improving the safety of the photocatalytic antibacterial material.

[0014] Preferably, the alkali solution in step (1) and step (2) is any one of ammonia water and sodium hydroxide.

[0015] Furthermore, the concentration of the alkali solution is 4 mM.

[0016] Preferably, the zinc salt in step (1) is Zn(NO3)2·6H2O;

[0017] The organic solvent A is hexamethylenetetramine.

[0018] Preferably, the copper salt in step (2) is CuSO4;

[0019] The organic solvent B is ethylenediaminetetraacetic acid or EDTA-Na2.

[0020] Preferably, in 1 L of the total mixed solution, the molar ratio of the zinc salt, the copper salt, the organic solvents A and B, and ascorbic acid is 25:5:12.5:2:(6.5-7.5).

[0021] Preferably, the constant temperature reaction temperature in step (2) is 65° C., and the reaction time is 30 minutes.

[0022] The beneficial effect achieved by the above technical solution is that: the present invention limits the isothermal reaction temperature to 65° C., which is conducive to the generation of zinc oxide precursor.

[0023] Preferably, the constant temperature incubation temperature in step (3) is 85° C., and the incubation time is 12 h.

[0024] The beneficial effects achieved by the above technical solution are as follows: the present invention limits the constant temperature incubation temperature to 85°C, which is the most suitable temperature for zinc oxide growth, is conducive to the formation of a hollow porous structure, and within a limited incubation time, can ensure that zinc oxide has a faster growth rate.

[0025] Preferably, the washing conditions in step (3) are: washing twice with deionized water and twice with ethanol.

[0026] Preferably, the microwave power in step (3) is 500-800W, and the microwave treatment time is 30min.

[0027] The beneficial effects achieved by the above technical solution are: microwave heat treatment can promote the continuous growth of ZnO seeds on the Cu2O surface, which has an important influence on the final formation of a porous and hollow structure of the material.

[0028] A Cu2O@ZnO visible light photocatalytic antibacterial material has a porous and hollow core-shell structure in which ZnO seed crystals are wrapped around the surface of Cu2O.

[0029] Preferably, the band gap of the Cu2O@ZnO visible light photocatalytic antibacterial material is 2.13-2.2 eV.

[0030] Preferably, the Cu2O@ZnO particles have a particle size of 1-3 μm.

[0031] Preferably, the pore size is 200-400 nm.

[0032] Application of a Cu2O@ZnO visible light photocatalytic antibacterial material as a wound drug carrier.

[0033] Preferably, the drug is angiogenesis factor.

[0034] Application of a Cu2O@ZnO visible light photocatalytic antibacterial material in bone implant drug carrier.

[0035] Preferably, the drug is a drug that promotes bone growth.

[0036] Furthermore, the drug that promotes bone growth is BMP2.

[0037] It can be seen from the above technical solution that compared with the prior art, the present invention discloses a Cu2O@ZnO visible light photocatalytic antibacterial material and a preparation method thereof, which has the following beneficial effects:

[0038] 1. Most conventionally synthesized Cu2O-ZnO composite materials are solid and have no pores, while the Cu2O@ZnO prepared in this invention has hollow and porous properties and can be used as a drug carrier;

[0039] 2. The present invention adopts a one-pot hydrothermal method for preparation, which is simple and safe, has a simple operation method, does not require high equipment, has low cost, and is suitable for large-scale production and industrialization;

[0040] 3. The coupling of ZnO and Cu2O can improve the utilization rate of solar energy, thereby improving the photocatalytic efficiency and the photocatalytic antibacterial performance of the material. It also solves the problems of Cu2O's instability and short antibacterial effect.

[0041] 4. The yellow light responded by the material finally prepared by the present invention has a milder nature and is less harmful to the human body, thus expanding the application scope of photocatalytic antibacterial. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0043] Figure 1 This is a scanning electron microscope image of Cu2O@ZnO prepared in Example 1 of the present invention.

[0044] Figure 2 This is a transmission electron microscope image of Cu2O@ZnO prepared in Example 1 of the present invention.

[0045] Figure 3 This is the energy band gap diagram of Cu2O@ZnO prepared in Example 1 of the present invention.

[0046] Figure 4 Schematic diagram of the photocatalytic antibacterial performance of Cu2O@ZnO prepared in Example 1 of the present invention under natural light and yellow light conditions.

[0047] Figure 5 This is a scanning electron microscope image of Cu2O@ZnO prepared in Comparative Example 1 of the present invention. DETAILED DESCRIPTION

[0048] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0049] The present invention discloses a method for preparing a Cu2O@ZnO visible light photocatalytic antibacterial material, comprising the following steps:

[0050] (1) Dissolve zinc salt in deionized water, then add alkali solution to adjust the pH to 10-12, then add organic solvent A and stir uniformly under closed conditions to obtain solution 1;

[0051] (2) Add copper salt and organic solvent B to solution 1, carry out constant temperature reaction at 65°C for 30 minutes, and then add alkali solution to react to obtain solution 2;

[0052] (3) adding ascorbic acid to solution 2, incubating at a constant temperature of 85° C. for 12 h, centrifuging, washing twice with deionized water and ethanol, freeze-drying, and microwave-treating at a microwave power of 500-800 W for 30 min to obtain the Cu2O@ZnO visible light photocatalytic antibacterial material.

[0053] Furthermore, the zinc salt is Zn(NO3)2·6H2O; the organic solvent A is hexamethylenetetramine; the copper salt is CuSO4; the organic solvent B is ethylenediaminetetraacetic acid or EDTA-Na2;

[0054] The alkali solution is any one of ammonia water and sodium hydroxide.

[0055] Wherein, in 1L of the total mixed solution, the molar ratio of zinc salt, copper salt, organic solvents A and B and ascorbic acid is 25:5:12.5:2:(6.5-7.5).

[0056] The finally prepared Cu2O@ZnO visible light photocatalytic antibacterial material has a core-shell structure with porous and hollow ZnO seeds wrapped on the surface of Cu2O.

[0057] Furthermore, the pore size is 200-400 nm, the Cu2O@ZnO particle size is 1-3 μm, and the band gap width of the Cu2O@ZnO visible light photocatalytic antibacterial material is 2.13-2.2 eV.

[0058] Example 1

[0059] A method for preparing a Cu2O@ZnO visible light photocatalytic antibacterial material comprises the following steps:

[0060] (1) Dissolve 50 mM Zn(NO3)2·6H2O in 200 mL of deionized water, then add ammonia to adjust the pH of the solution to 10-12. Then, dissolve 25 mM hexamethylenetetramine in deionized water and stir until completely dissolved. During this process, the container is completely sealed with a lid to prevent the ammonia from volatilizing.

[0061] (2) 10 mM CuSO4 and 4 mM EDTA were added to the solution in step (1) under stirring, and the mixture was placed in a 65°C constant temperature water bath for reaction for 30 min.

[0062] (3) 40 mL of 20 wt% NaOH solution was added dropwise to the solution of step (2) at a constant temperature of 65° C. with stirring, and the mixture was reacted for 5 min.

[0063] (4) Then, 14 mM ascorbic acid was added to the solution in step (3), and the mixed solution was incubated in a constant temperature water bath at 85°C for 12 hours.

[0064] (5) The product was collected by centrifugation and washed twice with deionized water and ethanol.

[0065] (6) The washed product was freeze-dried and then microwave-treated in a microwave oven with a microwave power of 500-800 W for 30 min to obtain Cu2O@ZnO visible light photocatalytic antibacterial material excited by visible light.

[0066] The molar volume concentration of each raw material component refers to the amount of each component in 1 L of the total mixed solution.

[0067] Summary: The Cu2O@ZnO photocatalytic antibacterial material finally prepared by the present invention is placed under an electron microscope and observed. Its overall structure is porous and hollow, and the ZnO seed crystals are wrapped around the surface of Cu2O to form a core-shell structure. Figure 1-2 .

[0068] Comparative Example 1

[0069] Compared with Example 1, except that the microwave treatment in step (6) is not performed, the other preparation steps and condition parameters are the same as those in Example 1.

[0070] The structure of the Cu2O@ZnO visible light photocatalytic antibacterial material finally prepared in Comparative Example 1 is detailed in Figure 5 , it can be seen that the surface of the sample without microwave treatment has less ZnO grown on it.

[0071] Effect verification

[0072] Test 1 Antibacterial effect

[0073] The bactericidal activity of the prepared samples was evaluated using Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) as model Gram-negative and Gram-positive strains. Specifically, the Cu2O@ZnO visible light photocatalytic antibacterial material was dispersed in 10 mL of bacterial suspension. The mixture was then irradiated with either yellow light or natural light for 3 hours. The number of colonies on the plates was then counted, and the survival rate was calculated using the plate count method.

[0074] For details, see Figure 4 ,in, Figure 4 The control group is bacteria without any treatment; the natural light group is the antibacterial effect of Cu2O@ZnO prepared in Example 1 under natural light conditions; the yellow light group is the antibacterial effect of Cu2O@ZnO prepared in Example 1 under yellow light conditions.

[0075] Summary: 1. The Cu2O@ZnO visible light photocatalytic antibacterial material prepared by the present invention has good antibacterial effect; 2. The yellow light responded by the antibacterial material has a milder nature and is less harmful to the human body, which expands the application range of photocatalytic antibacterial.

[0076] Test 2: Removal of bacterial residues

[0077] The Cu2O@ZnO prepared in Example 1 was added to the bacterial suspension and co-cultured at 37°C for 24 hours. The bacterial endotoxin content in the co-culture solution was measured using a bacterial endotoxin analyzer. Specifically:

[0078] First, a bacterial endotoxin working standard with a concentration of 100 EU / mL was diluted 10-fold with water dissolved in Limulus Amebocyte Lysate (LAL) to produce a series of standard aqueous solutions containing 10, 1.0, 0.1, and 0.01 EU / mL. The gelation time was measured using the Limulus Amebocyte Lysate (LAL) assay. A standard curve was plotted using the logarithm of the gelation time (lgt) against the logarithm of the bacterial endotoxin concentration (lgc). The same method was then used to determine the bacterial endotoxin content in water before and after Cu2O@ZnO treatment under certain operating conditions. The removal efficiency was calculated to be 94.67%. Fluorescence microscopy was used to observe the number of live and dead bacteria on the sample surface to assess the bacterial adsorption capacity of Cu2O@ZnO.

[0079] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0080] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a Cu2O@ZnO visible light photocatalytic antibacterial material, characterized in that: The following steps are involved: (1) Dissolve zinc salt in deionized water, then add ammonia water to adjust the pH to 10-12, then add A, where A is hexamethylenetetramine, and stir evenly under closed conditions to obtain solution 1; (2) adding copper salt and B to the solution 1, where B is ethylenediaminetetraacetic acid or EDTA-Na2, and reacting at a constant temperature, and then adding alkaline solution to react to obtain solution 2; (3) adding ascorbic acid to the second solution, and sequentially performing constant temperature incubation, centrifugation, washing, freeze drying, and microwave treatment to obtain the Cu2O@ZnO visible light photocatalytic antibacterial material; The microwave power is 500-800W, and the microwave treatment time is 30min; The Cu2O@ZnO visible light photocatalytic antibacterial material structure is a core-shell structure with multiple pores and a hollow core, and ZnO crystal seeds wrapped on the surface of Cu2O.

2. The method for preparing a Cu2O@ZnO visible light photocatalytic antibacterial material according to claim 1, characterized in that: The zinc salt in step (1) is Zn(NO3)2·6H2O.

3. The method for preparing a Cu2O@ZnO visible light photocatalytic antibacterial material according to claim 1, characterized in that: The copper salt in step (2) is CuSO4.

4. The method for preparing a Cu2O@ZnO visible light photocatalytic antibacterial material according to any one of claims 1 to 3, characterized in that: In 1 L of the total mixed solution, the molar ratio of the zinc salt, the copper salt, A and B, and ascorbic acid is 25:5:12.5:2:(6.5-7.5).

5. The method for preparing a Cu2O@ZnO visible light photocatalytic antibacterial material according to claim 1, characterized in that: The constant temperature reaction temperature of step (2) is 65° C., and the reaction time is 30 min.

6. The method for preparing a Cu2O@ZnO visible light photocatalytic antibacterial material according to claim 1, characterized in that: The constant temperature incubation temperature of step (3) is 85° C., and the incubation time is 12 h.

7. The method for preparing a Cu2O@ZnO visible light photocatalytic antibacterial material according to claim 1, characterized in that: The washing in step (3) is as follows: washing twice with deionized water and twice with ethanol.

8. The method for preparing a Cu2O@ZnO visible light photocatalytic antibacterial material according to claim 1, characterized in that: The pore size of the material is 200-400 nm.

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