Ag-tsa composite nanomaterial, preparation method and antibacterial application thereof

Abstract

The application discloses an Ag-TSA composite nanometer material, a preparation method and antibacterial application thereof, and belongs to the field of nanometer material preparation. The composite nanometer material takes silver nanoparticles AgNPs as a core and is combined with tea saponin molecules TSA, and a structural formula of the composite nanometer material is Ag-TSA. The Ag-TSA nanometer material based on tea saponin and combined with silver particles can obviously inhibit the growth of gram-negative bacteria and gram-positive bacteria. The Ag-TSA nanometer material is prepared by a green synthesis method through the reducing agent and surfactant performance of tea saponin. The nanometer material combines the antibacterial performance of silver nanoparticles and the hemolytic function of tea saponin, and has a synergistic inhibiting effect on the growth and reproduction of bacteria. Therefore, the Ag-TSA nanometer material based on tea saponin and combined with silver particles can obviously enhance the growth inhibiting effect of simple silver nanoparticles on bacteria, and has great application prospect.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of nanomaterial preparation, and relates to a composite material based on silver nanoparticles and tea saponin, in particular to an Ag-TSA composite nanomaterial, a preparation method and antibacterial application thereof. BACKGROUND

[0002] Silver nanoparticles have excellent antibacterial effect, wide antibacterial spectrum and are not prone to drug resistance. Therefore, silver nanoparticles and their composite materials have become one of the research hotspots in the field of antibacterial materials.

[0003] In the prior art, common silver particle synthesis methods include physical methods and chemical methods. Compared with physical synthesis methods such as mechanical grinding and laser burning, the chemical synthesis method for preparing silver nanoparticles has a simple preparation process, is easy and feasible to operate, and has low requirements on experimental conditions. However, the chemical reducing agents such as hydrazine hydrate, sodium borohydride, polyhydric alcohol and sodium citrate used in the traditional chemical synthesis method not only cannot achieve additive effect on antibacterial and mildew-proof effects, but also have certain toxicity, pollute the environment, and the residues in the product also limit the application of the synthesized silver particles in the fields of medicine and daily industry.

[0004] Tea saponin, also known as tea saponin (TSA), is a kind of glycoside compound extracted naturally, which is a light yellow fine powder. The pure product is a white fine columnar crystal after purification and decolorization. Tea saponin has the characteristics of wide raw material source, low cost, simple operation and green safety, and is a natural surfactant with good performance and hemolytic effect. The hemolytic mechanism of tea saponin is that tea saponin causes the change of the permeability of cell membranes containing cholesterol, leading to the destruction of the selective permeability and integrity of cell membranes, and then leading to the exosmosis of cytoplasm, and finally making the whole cell disintegrate, which is similar to the antibacterial mechanism. In addition, the excellent surface activity of tea saponin makes it widely used in light industry, chemical industry, pesticides, feed, breeding, textile, oil extraction, mining, building materials and highway construction fields.

[0005] At present, there is no related literature reported on the technology of tea saponin composite silver nanoparticles Ag-TSA. SUMMARY

[0006] In view of the deficiencies of the prior art, the purpose of the present application is to provide an Ag-TSA composite nanomaterial, a preparation method and antibacterial application thereof.

[0007] In order to achieve the above purpose, the present application provides the following technical solutions:

[0008] An Ag-TSA composite nanomaterial, which takes silver nanoparticles AgNPs as the core and composites tea saponin molecules TSA, and the structural formula is Ag-TSA.

[0009] Preferably, the composite nanomaterial is a uniform spherical structure with a particle size of 1-100 nm.

[0010] More preferably, the particle size of the composite nanomaterial is 2-15 nm.

[0011] Preferably, the composite nanomaterial has a characteristic ultraviolet absorption peak of about 420 nm.

[0012] The application provides a preparation method of the Ag-TSA composite nanomaterial, comprising:

[0013] S1. Under the condition of magnetic stirring, concentrated ammonia water (NH3·H2O) is slowly added to a freshly prepared silver nitrate (AgNO3) aqueous solution, the solution is first turbid and then clear, and after stirring for a predetermined time, the volume is adjusted to obtain a silver-ammonia solution;

[0014] S2. The obtained silver-ammonia solution and tea saponin TSA are added to a reaction container, and under the conditions of water bath heating and stirring, the reaction is set for a certain time to obtain the Ag-TSA composite nanomaterial.

[0015] Further, in the step S2, the mass ratio of AgNO3 to TSA is controlled to be 1:5-20.

[0016] Further, the mass ratio of AgNO3 to TSA is controlled to be 1:10.

[0017] Further, in the step S2, the reaction temperature is 65-67℃, the reaction time is 2-3 h, and the stirring rate is 500-800 rpm / min.

[0018] Further, the stirring rate is 600 rpm / min.

[0019] The application also provides an application of the Ag-TSA composite nanomaterial, which is used as an antibacterial agent to inhibit the growth and reproduction of bacteria.

[0020] The application introduces a natural plant extract tea saponin as a reducing agent and a surfactant to synthesize a tea saponin-silver nanoparticle composite material. Based on the good natural surfactant performance and hemolytic effect of tea saponin, the application proposes a green synthesis method for preparing silver nanoparticles by using tea saponin. The silver nanoparticles prepared by using tea saponin have good dispersibility and stability, and the application of the silver nanoparticles as a composite synergistic antibacterial agent in the direction of antibacterial and mildew prevention is further explored, and the application of the silver nanoparticles in the fields of medicine and health, textiles, daily chemical industry, food packaging and the like is increasingly extensive.

[0021] Principle of the present application: the Ag-TSA nanomaterial based on tea saponin composite silver particles in the present application can significantly inhibit the growth of gram-negative bacteria (E. coli) and positive bacteria (S. aureus). We use the reducing agent and surfactant properties of tea saponin to very simply prepare the Ag-TSA nanomaterial of tea saponin composite silver nanoparticles by a green synthesis method. The nanomaterial combines the antibacterial properties of silver nanoparticles and the hemolytic function of tea saponin, and has a synergistic inhibitory effect on the growth and reproduction of bacteria. Therefore, the Ag-TSA nanomaterial of tea saponin composite silver particles in the present application can significantly enhance the growth inhibition effect of simple silver nanoparticles on bacteria, and has great application prospect.

[0022] Compared with the prior art, the present application has the following beneficial effects:

[0023] (1) The present application provides a Ag-TSA nanomaterial based on tea saponin composite silver particles and a preparation method and application thereof.

[0024] (2) The present application provides a green synthesis of the Ag-TSA nanomaterial of tea saponin composite silver particles, which has a raw material utilization rate close to 100% conversion, does not produce any waste and by-products, prevents environmental pollution from the source, and realizes an environmentally friendly silver nanoparticle synthesis method.

[0025] (3) The raw materials used in the present application have reduced toxicity and environmental pollution, the product preparation process is simplified, the operation is simple, the product has reduced toxicity, the application field of antibacterial and mildew-proof is widened, and the like. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 TEM image of the Ag-TSA nanomaterial of tea saponin composite silver particles prepared in Example 1;

[0027] Figure 2 Characterization of the ultraviolet absorption performance of the Ag-TSA nanomaterial of tea saponin composite silver particles in Example 1;

[0028] Figure 3 TEM image of the Ag-TSAx nanomaterial of tea saponin composite silver particles prepared in Example 2;

[0029] Figure 4 Characterization of the ultraviolet absorption performance of the Ag-TSAx nanomaterial of tea saponin composite silver particles in Example 2;

[0030] Figure 5 TEM image of the Ag-TSArt nanomaterial of tea saponin composite silver particles prepared in Example 3;

[0031] Figure 6For the characterization of the UV absorption performance of the tea saponin composite silver particle Ag-TSA nano material in Example 3;

[0032] Figure 7 For the characterization of the UV absorption performance of the tea saponin composite silver particle Ag-TSA nano material in Example 3;

[0033] Figure 8 For the characterization of the UV absorption performance of the tea saponin composite silver particle Ag-TSA nano material in Example 3;

[0034] Figure 9 For the characterization of the UV absorption performance of the tea saponin composite silver particle Ag-TSA nano material in Example 3;

[0035] Figure 10 For the characterization of the UV absorption performance of the tea saponin composite silver particle Ag-TSA nano material in Example 3; DETAILED DESCRIPTION

[0036] The specific embodiments of the present application are further illustrated by the following examples, but the specific embodiments of the present application are not limited to the following examples.

[0037] Synthesis of tea saponin composite silver particle Ag-TSA nano material: under the condition of magnetic stirring, concentrated ammonia water (NH3·H2O) was slowly added to the freshly prepared silver nitrate (AgNO3) aqueous solution, and the solution first became turbid and then became clear. After continuing to stir for several minutes, the volume was adjusted to obtain a silver-ammonia solution. The silver-ammonia solution and tea saponin (Tea Saponin) were added to a reaction vessel, and the reaction was completed under the condition of water bath heating and magnetic stirring for a set time to obtain the tea saponin composite silver nano particle Ag-TSA aqueous solution.

[0038] The specific embodiments of the present application are further illustrated by the following examples, but the specific embodiments of the present application are not limited to the following examples.

[0039] Example 1

[0040] The preparation process of the tea saponin composite silver particle Ag-TSA nano material includes the following steps:

[0041] 0.17 g of silver nitrate was weighed and dissolved in 9 mL of water. Under the condition of magnetic stirring, concentrated ammonia water was slowly added to the silver nitrate aqueous solution, and the solution first became turbid and then became clear. After continuing to stir for several minutes, the volume was adjusted to 10 mL to prepare 0.1 mol L -1 of silver-ammonia solution. 4 mL of fresh silver-ammonia solution and 16 mL of 40 mg mL -1The tea saponin solution is added into a reaction container, and the reaction is completed after 2-3 hours of heating at 65-67°C in a water bath and magnetic stirring. The green synthesis reaction produces a tea saponin composite silver nanoparticle Ag-TSA aqueous solution.

[0042] The tea saponin composite silver nanoparticle Ag-TSA nanomaterial prepared in this example is subjected to TEM and ultraviolet absorption spectrum tests, and the results are shown in Figure 1 and Figure 2 It can be seen from Figure 1 that the average size of the Ag-TSA nanomaterial prepared in this example is 2-15 nm. It can be seen from Figure 2 that the characteristic ultraviolet absorption peak of the Ag-TSA nanomaterial prepared in this example is ~420 nm.

[0043] Example 2

[0044] The preparation process of the tea saponin composite silver nanoparticle Ag-TSAx nanomaterial includes the following steps:

[0045] 0.17 g of silver nitrate is weighed and dissolved in 9 mL of water. Under the condition of magnetic stirring, concentrated ammonia water is slowly added dropwise to the silver nitrate aqueous solution. After the solution becomes turbid and then clear, continue to stir for a few minutes and then dilute to 10 mL to prepare a 0.1 mol L -1 silver ammonia solution. 4 mL of fresh silver ammonia solution and 16 mL of 20 mg mL -1 tea saponin solution are added into a reaction container, and the reaction is completed after 2-3 hours of heating at 65-67°C in a water bath and magnetic stirring. The reaction mixture solution is washed three times with water / ethanol to obtain a washed tea saponin composite silver nanoparticle Ag-TSAx solution.

[0046] The tea saponin composite silver nanoparticle Ag-TSAx nanomaterial prepared in this example is subjected to TEM and ultraviolet absorption spectrum tests, and the results are shown in Figure 5 and Figure 6 It can be seen from Figure 5 that the average size of the Ag-TSA nanomaterial prepared in this example is 2-10 nm. It can be seen from Figure 6 that the characteristic ultraviolet absorption peak of the Ag-TSA nanomaterial prepared in this example is ~420 nm.

[0047] Example 3

[0048] The preparation process of the tea saponin composite silver nanoparticle Ag-TSArt nanomaterial includes the following steps:

[0049] Take 0.17 g of silver nitrate, dissolved in 9 mL of water, under the condition of magnetic stirring, to the silver nitrate aqueous solution slowly drop by drop add concentrated ammonia water, after the solution first becomes turbid and then becomes clear, continue to stir for several minutes and then make up to 10 mL, to prepare 0.1 mol L -1 Silver ammonia solution. Add 4 mL of fresh silver ammonia solution and 8 mL of 10 mg mL -1 Tea saponin solution to the reaction vessel, under the condition of room temperature 25℃ and magnetic stirring, the reaction is completed after 24 hours, and the reaction obtains tea saponin composite silver nanoparticles Ag-TSArt aqueous solution.

[0050] The tea saponin composite silver nanoparticles Ag-TSArt nanomaterial prepared in this example is subjected to TEM and ultraviolet absorption spectrum test, and the results are shown in Figure 3 and Figure 4 It can be seen from Figure 3 that the average size of the Ag-TSArt nanomaterial prepared in this example is 1-30 nm. It can be seen from Figure 4 that the characteristic ultraviolet absorption peak of the Ag-TSArt nanomaterial prepared in this example is about 405 nm.

[0051] Example 4

[0052] Determination of the minimum inhibitory concentration (MIC) of the tea saponin composite silver nanoparticles Ag-TSArt nanomaterial:

[0053] The tea saponin composite silver nanoparticles Ag-TSArt nanomaterial obtained in Example 1 is compared with silver nanoparticles AgNPs alone, silver ion aqueous solution Ag + (AgNO3 and tea saponin aqueous solution, dissolved and diluted to the target concentration using broth culture medium, and the minimum inhibitory concentration of each silver nanomaterial to Escherichia coli and Staphylococcus aureus is determined by micro-broth dilution method.

[0054] Add 100 uL of LB broth medium to each well of a 96-well plate. Add 100 uL of prepared silver nanomaterial solution to the first well, then perform a two-fold dilution of the nanomaterial. That is, after adding the material to the first well, use a pipette to thoroughly pipette at least three times to mix the material with the broth, then pipette 100 uL into the second well and thoroughly pipette again to mix it with the broth, and so on until the last well, and discard 100 uL from the eighth column. Add 100 uL of diluted bacterial solution to each well, and repeat three groups. On the same plate, perform a row of negative controls (add only the nanomaterial, broth, and no bacterial solution) and a row of positive controls (add only the bacterial solution, no nanomaterial). Place the 96-well plate in a 37°C incubator for 24 hours, and then observe the results. Observe the negative and positive controls, and if there is white precipitation at the bottom of the plate, and the solution is more turbid than the negative control, it indicates that the bacteria are growing, and is marked with a “+”. If the mixed bacterial solution in the well is clear, it indicates that the growth of the bacteria is inhibited, and is marked with a “-”. When the growth of the bacteria is inhibited, the minimum concentration of the solution added to the last well is the MIC of the silver nanomaterial.

[0055] The MIC results are shown in Tables 1 and 2. Figure 7 and Figure 8 The MIC value of the tea saponin-silver particle composite nanomaterial Ag-TSA for E. coli is 62.5 mg / L -1 , and the MIC value for S. aureus is 125 mg / L -1 ; and the MIC value of the non-composite silver nanoparticle for E. coli and S. aureus is 500 mg / L -1 ; and a low concentration of tea saponin does not show a significant effect on inhibiting bacterial growth. Thus, the tea saponin-silver particle composite nanomaterial Ag-TSA has a good antibacterial effect on both gram-positive and gram-negative bacteria. Compared to the non-composite silver nanoparticle, it has a better inhibitory effect on the growth of E. coli and S. aureus.

[0056] Example 5

[0057] Determination of the minimum bactericidal concentration (MBC) of the tea saponin-silver particle composite nanomaterial Ag-TSA:

[0058] Use a inoculating loop to dip the mixed solution in each culture well in the MIC experiment, and continuously streak in the area divided on the nutrient agar medium, and then incubate in a 37°C incubator for 24 hours. Observe the growth of the bacteria on the culture dish, and if there are colonies, mark it with a “+”; if not, mark it with a “-”. The minimum concentration of the silver nanomaterial solution when marked with a “-” is the MBC.

[0059] At certain concentrations, the antibacterial agent did not kill all bacteria, but only inhibited the growth and reproduction of the vast majority. Therefore, this experiment further determined the minimum bactericidal concentration of the tea saponin composite silver particle Ag-TSA nanomaterial against Escherichia coli and Staphylococcus aureus.

[0060] The result is as follows Figure 9 As shown, the MBC value of the tea saponin composite silver particle Ag-TSA nanomaterial against Escherichia coli is 125 mg / L. -1 MBC value for Staphylococcus aureus >500 mg / L -1 The non-composite silver nanoparticles showed MBC values ​​>500 mg L⁻¹ against both Escherichia coli and Staphylococcus aureus; low concentrations of tea saponin also did not show significant bactericidal activity. Therefore, it can be concluded that the preparation of... Figure 10 The MBC table of various nanomaterials against bacteria shows that, compared with non-composite silver nanoparticles, the tea saponin composite silver particle Ag-TSA nanomaterial has a better bactericidal effect against Escherichia coli and Staphylococcus aureus.

[0061] The above content is only a specific implementation example of the present invention, and not all application examples of the present invention. All schemes that follow the technical concept of the present invention or make modifications based on the technical concept of the present invention are within the protection scope of the claims of the present invention.

Claims

1. A preparation method of Ag-TSA composite nanomaterials, characterized in that, The application relates to a preparation method of a silver-tea saponin (Ag-TSA) composite nanomaterial. S1, under the condition of magnetic stirring, concentrated ammonia water is slowly added into freshly prepared silver nitrate aqueous solution, the solution becomes turbid first and then clear, after a predetermined time of continuous stirring, the silver ammonia solution is obtained by constant volume; S2, the obtained silver ammonia solution and tea saponin TSA are added into a reaction container, under the conditions of water bath heating and stirring, the Ag-TSA composite nanomaterial is obtained after a set time of reaction. In the step S2, the reaction temperature is 65-67 DEG C. The composite nanomaterial takes silver nanoparticles AgNPs as the core and is compounded with tea saponin molecules TSA, and the structural formula is Ag-TSA. 2.The preparation method of the Ag-TSA composite nanomaterial according to claim 1, characterized in that, The composite nanomaterial is a uniform spherical structure, and the particle size is 1-100 nm.

3. The preparation method of the Ag-TSA composite nanomaterial according to claim 2, characterized in that, The particle size of the composite nanomaterial is 2-15 nm. 4.The preparation method of the Ag-TSA composite nanomaterial according to claim 1, characterized in that, The characteristic ultraviolet absorption peak of the composite nanomaterial is about 420 nm. 5.The preparation method of the Ag-TSA composite nanomaterial according to claim 1, characterized in that, In the step S2, the mass ratio of AgNO3 and TSA is controlled to be 1:5-20. 6.The preparation method of the Ag-TSA composite nanomaterial according to claim 1, characterized in that, The mass ratio of AgNO3 and TSA is controlled to be 1:

10. 7.The preparation method of the Ag-TSA composite nanomaterial according to claim 1, characterized in that, In the step S2, the reaction time is 2-3 h, and the stirring rate is 500-800 rpm / min. 8.The preparation method of the Ag-TSA composite nanomaterial according to claim 7, characterized in that, The stirring rate is 600 rpm / min.

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