Preparation method of cinnamyl aldehyde loaded silicon dioxide nano antibacterial agent

Abstract

The invention discloses a preparation method of a cinnamyl aldehyde loaded silicon dioxide nano antibacterial agent, relates to a preparation method of a nano antibacterial agent, and aims to solve the technical problem that the antibacterial effect is influenced due to the fact that the conventional cinnamyl aldehyde antibacterial agent is easy to volatilize and poor in water solubility. The preparation method comprises the following steps: adding silicon dioxide into an alcohol solution of cinnamyl aldehyde, heating to boil, carrying out reflux reaction, and then centrifugally separating out a precipitate, thereby obtaining the cinnamyl aldehyde loaded silicon dioxide nano antibacterial agent. When the concentration of the nano-antibacterial agent is 0.4-1g / L, the diameter of an inhibition zone of the nano-antibacterial agent to staphylococcus aureus is about 30-55mm, and the diameter of an inhibition zone of the nano-antibacterial agent to escherichia coli is about 27-45mm. The method can be used in the field of antibacterial agents.

Description

Technical Field

[0001] The invention relates to a preparation method of a nano antibacterial agent, and belongs to the technical field of organic antibacterial agents. Background Art

[0002] As a natural and highly effective antibacterial agent, cinnamaldehyde has very good application prospects in antibacterial treatment during food processing and storage. The excellent antibacterial effect of cinnamaldehyde comes from its aldehyde functional group. Since the aldehyde group is a nucleophilic group, it is easily adsorbed by the hydrophilic group on the surface of bacteria and penetrates into the cell wall, destroying the polysaccharide structure of the cell wall of bacteria and fungi to exert an antibacterial or bactericidal effect. Mammals do not have cell walls, so cinnamaldehyde will not damage human and animal cells. The advantages of cinnamaldehyde include relatively low cost, low level of cytotoxicity, high chemical diversity and biochemical specificity, and it is not easy to develop resistance to antibiotics. However, the physical and chemical properties of cinnamaldehyde are unstable, volatile, and poorly water-soluble, which limits the application of cinnamaldehyde as an antibacterial agent in many fields such as daily necessities and textiles. Summary of the invention

[0003] The invention aims to solve the technical problem that the existing cinnamaldehyde antibacterial agent is easy to volatilize and has poor water solubility, thereby affecting the antibacterial effect, and provides a preparation method of a cinnamaldehyde-loaded silicon dioxide nano antibacterial agent.

[0004] The preparation method of the cinnamaldehyde-loaded silica nano antibacterial agent of the present invention is carried out according to the following steps:

[0005] 1. Place the nano-silicon dioxide in a high-temperature furnace, heat it to 750-800° C. in a H2 atmosphere, and calcine it for 2-2.5 hours to obtain pretreated nano-silicon dioxide; in this step, the nano-silicon dioxide is calcined in a H2 atmosphere to remove impurities on the surface of SiO2, and at the same time, the specific surface of the silica carrier is modified, and such surface modification can enhance the stability of the cinnamaldehyde loading and improve the antibacterial effect;

[0006] 2. Add cinnamaldehyde to anhydrous ethanol at a concentration of 0.63-7.95 mol / L, mix well, and obtain an alcohol solution of cinnamaldehyde;

[0007] 3. Add the alcohol solution of cinnamaldehyde and the pretreated nano-silica into a reactor with a condensation reflux device, heat to boiling and reflux for 2 to 2.5 hours. After the reaction is completed, separate the precipitate by centrifugation to obtain the cinnamaldehyde-loaded silica nano-antibacterial agent.

[0008] Furthermore, the average particle size of the nano-silicon dioxide described in step 1 is 10 to 20 nm.

[0009] Furthermore, the ratio of the mass of cinnamaldehyde in the alcohol solution of cinnamaldehyde described in step three to the mass of the pretreated nano-silicon dioxide is (0.4-1.2):1.

[0010] Compared with the prior art, the present invention has the following beneficial effects:

[0011] The present invention uses cinnamaldehyde and anhydrous ethanol as raw materials, and uses nano-SiO2 to load cinnamaldehyde, so that the obtained antibacterial agent is stable and not easy to be lost. Secondly, after SiO2 is calcined in H2 atmosphere, impurities on the surface of SiO2 can be effectively removed. At the same time, the specific surface of the silica carrier is modified, and the loading stability of cinnamaldehyde and the antibacterial effect of the antibacterial agent are improved after surface functionalization modification.

[0012] The nano organic antibacterial agent of the present invention is not only non-toxic and environmentally friendly, but also not easy to develop drug resistance to antibiotics. At the same time, the cinnamaldehyde-loaded silicon dioxide nano antibacterial agent can form a quasi-net structure, which can effectively expand the antibacterial range, avoid the volatilization of effective antibacterial components, and greatly improve the antibacterial efficiency.

[0013] The cinnamaldehyde-loaded silica nano antibacterial agent of the present invention utilizes the unstable characteristics of the terpenes of cinnamaldehyde to interfere with the enzyme reaction in energy metabolism, thereby inhibiting respiration and causing bacterial cell death. It not only improves the volatilization of organic materials, has no pungent odor, but also is not easy to develop resistance to antibiotics.

[0014] The cinnamaldehyde-loaded silicon dioxide nano antibacterial agent of the present invention has an inhibition zone diameter of about 30 to 55 mm for Staphylococcus aureus and an inhibition zone diameter of about 27 to 45 mm for Escherichia coli when the antibacterial agent concentration is 0.4 to 1 g / L, achieving a good antibacterial effect and can be used in the field of antibacterial agents. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a photo of the nano organic antibacterial agent prepared in Example 1;

[0016] Figure 2 This is a high-magnification transmission electron microscopy image of the nano-organic antibacterial agent prepared in Example 1;

[0017] Figure 3 This is a diagram showing the antibacterial effects of the nano-organic antibacterial agent prepared in Example 1 at different concentrations. DETAILED DESCRIPTION

[0018] The beneficial effects of the present invention are verified by the following examples.

[0019] Example 1: The preparation method of the cinnamaldehyde-loaded silica nano-antibacterial agent of this embodiment is carried out according to the following steps:

[0020] 1. Place nano-silicon dioxide with an average particle size of 15 nm into a high-temperature furnace, heat it to 800°C in a H2 atmosphere and calcine it for 2 hours to obtain pretreated nano-silicon dioxide;

[0021] 2. Add cinnamaldehyde to anhydrous ethanol at a concentration of 7.95 mol / L, mix well, and obtain an alcohol solution of cinnamaldehyde.

[0022] 3. Add 5 mL of cinnamaldehyde alcohol solution and 10 g of pretreated nano-silica into a reactor with a condensation reflux device, heat to boiling and reflux for 2 hours. After the reaction, centrifuge and separate the precipitate to obtain the cinnamaldehyde-loaded silica nano-antibacterial agent.

[0023] The actual photo of the cinnamaldehyde-loaded silica nano-antibacterial agent prepared in Example 1 is as follows Figure 1 As shown. Figure 1 It can be seen that the antibacterial agent is in gel form.

[0024] Figure 2 This is a high-magnification transmission electron microscopy image of the cinnamaldehyde-loaded silica nano-antibacterial agent prepared in Example 1. Figure 2 It can be seen that the particle size of the antibacterial agent is about 40 nanometers, and the cinnamaldehyde is coated on the surface of the silica with a particle size of 15 nm, causing the particle size to grow larger.

[0025] 0.02g, 0.04g, 0.06g, 0.08g and 0.1g of the cinnamaldehyde-loaded silica nano-antibacterial agent prepared in Example 1 were added to 100mL of bacterial suspension for antibacterial experiments, and the bacterial suspension without antibacterial agent was used as a control. Staphylococcus aureus (S. aure) and Escherichia coli (E. coli) were selected for antibacterial experiments. The antibacterial effects obtained after 24 hours are as follows: Figure 3 The inhibition zone diameter data are shown in Table 1.

[0026] Table 1 Effect of cinnamaldehyde loaded silica nano antibacterial agent prepared in Example 1

[0027]

[0028] From Table 1 and Figure 1 It can be seen that with the increase in the amount of the cinnamaldehyde-loaded silica nano-antibacterial agent prepared in Example 1, the diameter of the inhibition zone becomes larger and larger, and when the concentration of the antibacterial agent is 0.4-1 g / L, a good antibacterial effect can be obtained on Staphylococcus aureus and Escherichia coli.

[0029] Example 2: The preparation method of the cinnamaldehyde-loaded silica nano-antibacterial agent of this example is carried out according to the following steps:

[0030] 1. Place nano-silicon dioxide with an average particle size of 20 nm into a high-temperature furnace, heat it to 750°C in a H2 atmosphere, and calcine it for 2.5 hours to obtain pretreated nano-silicon dioxide;

[0031] 2. Add cinnamaldehyde to anhydrous ethanol at a concentration of 1.27 mol / L, mix well, and obtain an alcohol solution of cinnamaldehyde.

[0032] 3. Add 5 mL of cinnamaldehyde alcohol solution and 1 g of pretreated nano-silica into a reactor with a condensation reflux device, heat to boiling and reflux for 2 hours. After the reaction, centrifuge and separate the precipitate to obtain the cinnamaldehyde-loaded silica nano-antibacterial agent.

[0033] The cinnamaldehyde-loaded silica nano-antibacterial agent prepared in Example 2 was used for antibacterial tests. When the antibacterial agent concentration was 0.4 g / L, the diameter of the antibacterial zone for Staphylococcus aureus was about 30 mm, and the diameter of the antibacterial zone for Escherichia coli was about 27 mm, achieving good antibacterial effects.

Claims

1. A method for preparing a cinnamaldehyde-loaded silica nano-antibacterial agent, characterized in that The method proceeds as follows:

1. Place the nano-silicon dioxide in a high-temperature furnace, heat it to 750-800° C. in a H2 atmosphere, and calcine it for 2-2.5 hours to obtain pretreated nano-silicon dioxide; in this step, the nano-silicon dioxide is calcined in a H2 atmosphere to remove impurities on the surface of SiO2, and at the same time, the specific surface of the silica carrier is modified, and such surface modification can enhance the stability of the cinnamaldehyde loading and improve the antibacterial effect; 2. Add cinnamaldehyde to anhydrous ethanol at a concentration of 0.63-7.95 mol / L, mix well, and obtain an alcohol solution of cinnamaldehyde; 3. Add the alcohol solution of cinnamaldehyde and the pretreated nano-silica into a reactor with a condensation reflux device, heat to boiling and reflux for 2 to 2.5 hours. After the reaction is completed, separate the precipitate by centrifugation to obtain the cinnamaldehyde-loaded silica nano-antibacterial agent.

2. The method for preparing a cinnamaldehyde-loaded silica nano-antibacterial agent according to claim 1, characterized in that: The average particle size of the nano-silicon dioxide described in step 1 is 10 to 20 nm.

3. The method for preparing a cinnamaldehyde-loaded silica nano-antibacterial agent according to claim 1 or 2, characterized in that: The ratio of the mass of cinnamaldehyde in the alcohol solution of cinnamaldehyde described in step three to the mass of the pretreated nano-silicon dioxide is (0.4-1.2):1.

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