CN114223671A

CN114223671A - Bimetal nano-structure antibacterial composition and preparation method thereof

Info

Publication number: CN114223671A
Application number: CN202111570609.9A
Authority: CN
Inventors: 刘甜恬; 黎奚; 徐梦媛; 陈捷晗; 郑惠莹; 林夏子
Original assignee: Guangdong Pharmaceutical University
Current assignee: Guangdong Pharmaceutical University
Priority date: 2021-12-21
Filing date: 2021-12-21
Publication date: 2022-03-25

Abstract

The invention belongs to the field of nano materials, and particularly relates to a bimetal nano-structure antibacterial composition and a preparation method thereof. The synthesized nano material MIL-101(Fe) @ Ag crystal has regular shape, a three-dimensional structure and uniform particle distribution, and has obvious inhibiting effect on escherichia coli and staphylococcus aureus. The antibacterial performance of the synthesized product is detected by a flat plate coating method, and when the concentration of MIL-101(Fe) @ Ag is 100 mug/mL, the inhibition effect on escherichia coli and staphylococcus aureus is obvious.

Description

Bimetal nano-structure antibacterial composition and preparation method thereof

Technical Field

The invention belongs to the field of nano materials, and particularly relates to a bimetal nano-structure antibacterial composition and a preparation method thereof.

Background

Metal organic framework Materials (MOFs) are a new material with a topological structure, which is bridged by multidentate organic ligands and metal ions or metal clusters. The material not only has high specific surface area and larger pore volume, but also can synthesize materials with different pore diameters by changing the types of ligands, and purposefully designs the material according to different requirements. MOFs materials have been synthesized in a wide variety of crystal types from the first synthesis to the present, covering six broad classes, including ZIF-series materials, MIL-series materials, and the like. At present, MOFs are widely applied to the fields of energy storage materials, gas adsorption and separation, catalysis, sensing, magnetism, fluorescence and the like. Due to the nature of the MOFs structure, it can be used for the above series of applications. The excellent specific surface area and pores of the MOFs material are used for adsorption and separation, and the MOFs material can also be applied to a catalyst as some materials due to different ligands carried by the MOFs material.

However, the traditional antibacterial materials face the problem of bacterial drug resistance, so that the sterilization capability of the traditional medicines to bacteria is continuously weakened. Antibacterial materials have been used since ancient times and are gradually optimized in the development process, but due to the limitations of traditional medicines, the MOFs materials are gradually excavated. Although MOFs materials have been gradually developed in the medical field, there are still many problems that have not been solved. For example, in the synthesis process of the MOFs, the structure of the nano-material is affected by the ultrasonic time, and the sufficient reaction of the material is affected by the direct mixing of the two materials. In the existing hydrothermal synthesis technology, the duration of heating also influences the synthesis of the product.

Chinese patent application CN 109820000A discloses a MOFs-carried nano-silver antibacterial material and a preparation method thereof, wherein a porous material MOFs with a tailorable structure, a large specific surface area and a plurality of topological structures is used as a template, and nano-silver is carried on the surface, the framework and the pore channel of the MOFs to synthesize an Ag @ MOFs high-efficiency antibacterial material with uniform size and easy dispersion. The glucose solution with a specific proportion participates in the reaction, so that the problem that the antibacterial performance of the silver nanoparticles is influenced because the silver nanoparticles are easily spontaneously aggregated into large particles and cannot be effectively and uniformly dispersed in a matrix material is solved.

Chinese patent application CN 111109293A relates to a novel Ag NPs @ ZIF-8 composite material formed by in-situ growth of nano-silver (Ag NPs) on the surface, the framework and the pore channel of ZIF-8 Metal Organic Frameworks (MOFs). The morphology and particle size of ZIF-8 can be regulated and controlled by changing the content and reaction time of 2-methylimidazole and zinc acetate, so that the adsorption of silver-ammonia molecules in ZIF-8 pores is influenced, the growth size of silver in the ZIF pores is limited, and high-antibacterial-property nano-silver particles are generated; meanwhile, a large amount of silver ions enter the pores and the surface of the ZIF-8, so that the silver carrying efficiency of the rechecking material is improved, and the antibacterial effect is realized. However, the above patent applications do not verify the antibacterial effect of the obtained product by an antibacterial test. The antibacterial effective concentration of the currently synthesized MOFs material is still in the range of 5-10mg/mL, and the level of ug/mL or even lower is not reached yet. The demand for synthesizing new MOFs antibacterial materials is urgent for researching lower sterilization or bacteriostasis concentration.

Disclosure of Invention

In order to solve the problems of the prior art, the present invention aims to provide a bimetal nanostructure antibacterial composition and a preparation method thereof. The invention relates to a novel MOFs material synthesis technology, which realizes the antibacterial effect on bacteria by synthesizing a novel nano material MIL-101(Fe) @ Ag and researches the toxic effect on cells so as to be applied later.

The technical scheme of the invention is as follows:

a method for preparing a bi-metallic nanostructured antimicrobial composition comprising the steps of:

s1: FeCl is added₃·6H₂Fully grinding O and terephthalic acid in a mortar, adding the ground O and the terephthalic acid into N, N-dimethylformamide, and ultrasonically treating the mixture to obtain turbid suspension I;

s2: adding silver nitrate into 70 ℃ absolute ethyl alcohol, and then adding the absolute ethyl alcohol containing the silver nitrate into the turbid suspension I to obtain a turbid suspension II; sealing the turbid suspension II in a stainless steel reaction kettle with a teflon lining, heating at 120 ℃ for 24 hours to obtain orange mud, and performing centrifugal separation to obtain orange mud;

s3: and (3) respectively cleaning the orange mud with DMF (dimethyl formamide) and hot ethanol at 70 ℃, centrifuging to remove unreacted raw materials, and keeping the cleaned orange mud at 150 ℃ for 12h to activate the orange mud, so as to obtain the bimetal nano-structure antibacterial composition.

Further, N-dimethylformamide and FeCl in the step S1₃·6H₂The dosage ratio of O is 20-40 mL: 1.351 g; the using amount ratio of the absolute ethyl alcohol to the silver nitrate in the step S2 is 5-10 mL: 0.3532 g.

Further, FeCl in the step S1₃·6H₂The molar ratio of O to terephthalic acid is 2: 1.

further, the amount of silver nitrate added in step S2 is FeCl₃·6H₂2-20% of the total mass of O and terephthalic acid.

Further, the silver nitrate is added in FeCl in the step S2₃·6H ₂20 percent of the total mass of O and terephthalic acid.

Further, the ultrasound time in the step S1 is 15min, and the ultrasound power is 120W.

Further, the centrifugal speed in the steps S2, S3 is 4000 rmp.

Further, the orange paste is washed with DMF 1 time in the step S3; the orange paste was washed 2 times with hot ethanol at 70 ℃.

Moreover, the invention also provides a bimetal nano-structure antibacterial composition and application thereof in preparing antibacterial materials. The optimal concentration of the antimicrobial bimetallic nanostructured antimicrobial composition in this application is as follows: the corresponding concentration of the escherichia coli is more than 80ug/mL, and the corresponding concentration of the staphylococcus aureus is more than 60 ug/mL.

Compared with the prior art, the bimetal nanostructure antibacterial composition provided by the invention has the following advantages:

1) according to the invention, silver nitrate with a certain mass is directly added during synthesis of MOFs (metal-organic frameworks), so that silver ions and FeCl in a mixed solution₃·6H₂And fully reacting the O and the terephthalic acid in a reaction container to obtain a novel MOFs bimetal structure loaded with silver ions. The obtained MOFs bimetal structure is weakly magnetic nano particles, the appearance is composite cubic crystal particles, the crystal appearance is regular, and a three-dimensional structure is presented.

2) The 20% MIL-101(Fe) @ Ag synthesized by the invention can inhibit the growth of bacteria when the concentration is lower than 100 ug/mL. The antibacterial performance of the synthesized product is detected by a flat plate coating method, and the antibacterial effect on escherichia coli is remarkable when the concentration of 20% MIL-101(Fe) @ Ag synthesized by the method is 100 mug/mL; even the survival rate of staphylococcus aureus is only about 10%.

3) The bimetal nanostructure antibacterial composition obtained by the invention has low toxic and side effects, stable chemical properties and good antibacterial activity.

Drawings

FIG. 1 is a diagram of the fully ground starting material from the synthesis of example 1;

in FIG. 2, a is an XRD spectrum of the product obtained in example 1 and comparative examples 1 to 3; b is the XRD spectrum of 20% MIL-101(Fe) @ Ag;

FIG. 3 is an IR spectrum of the product obtained in example 1;

FIG. 4 is an SEM photograph of the product obtained in example 1;

FIG. 5a is a graph of the nano-particle size analysis of the product obtained in example 1; b is a Zeta potential analysis plot of the product obtained in example 1;

FIG. 6 is a Thermogravimetric (TG) plot of the product obtained in example 1;

FIG. 7a is a graph of optical density at 600 nm for E.coli at different concentrations of 20% MIL-101(Fe) @ Ag; b is the optical density plot at 600 nm of Staphylococcus aureus at different concentrations of 20% MIL-101(Fe) @ Ag;

FIG. 8a is a graph of E.coli viability test (%) at different concentrations of 20% MIL-101(Fe) @ Ag and MIL-101 (Fe); b is a graph of activity test (%) of E.coli at different concentrations of 20% MIL-101(Fe) @ Ag and MIL-101 (Fe);

FIG. 9a is a bacterial MTT assay (E.coli) of the product obtained in example 1; b is the bacterial MTT profile of the product obtained in example 1 (Staphylococcus aureus);

FIG. 10 is a graph showing cytotoxicity test of the product obtained in example 1.

Detailed Description

The present invention is further illustrated by the following description of specific embodiments, which are not intended to limit the invention, and various modifications and improvements can be made by those skilled in the art based on the basic idea of the invention, but the invention is within the protection scope of the invention.

Wherein, the reagents used in the invention are all common reagents and can be purchased from common reagent production and sale companies.

Example 1: preparation method of bimetal nano-structure antibacterial composition

1.351g of FeCl₃·6H₂O (5mmol) and 0.415g (2.5mmol) of terephthalic acid (H)₂BDC) were mixed in 30mL of Dimethylformamide (DMF), sonicated for 15min to make a cloudy suspension, and then 0.3532g of silver nitrate (H)₂BDC and FeCl₃·6H ₂20% of the mass of O), adding into 6mL of 70 ℃ absolute ethyl alcohol, and adding the silver nitrate-containing absolute ethyl alcohol into the turbid suspension; sealing the suspension in a stainless steel reaction kettle with a Teflon lining, heating at 120 ℃ for 24h to obtain orange mud, and separating by centrifugation (4000rmp, 10min) to obtain orange mud; washing the orange paste with DMF (1 time washing) and hot ethanol (twice washing at 70 deg.C) and centrifuging (4000rmp, 15min) to remove unreacted raw materials, and keeping the washed orange paste at 150 deg.C for 12h to activate it, to obtain 20% MIL-101(Fe) @ Ag.

Wherein the FeCl₃·6H₂The purity of O was 98% and the purity of silver nitrate was 99%.

Example 2:

example 2 the preparation process is similar to example 1, except that silver nitrate is added in an amount of FeCl₃·6H ₂2% by mass of both O and terephthalic acid.

Example 3:

example 3 the preparation process is similar to example 1, except that silver nitrate is added in an amount of FeCl₃·6H ₂10% by mass of both O and terephthalic acid.

Comparative example 1:

the preparation process described in comparative example 1 is similar to that of example 1, except that no silver nitrate is added.

The first test example: nano representation of bimetal nano-structure antibacterial composition obtained in examples 1-3 and comparative example 1 of the invention

1. Characterization of nanomaterials

XRD was measured by Rigaku + UltimaIV; the infrared spectrum is obtained by Bruker Fourier transform infrared spectrometer of ALPHA II; scanning electron microscopy was determined by TESCAN MIRA 4; the nanometer particle size and the Zeta potential are measured by a Malvern Zetasizer Nano ZS 90; thermogravimetry was determined by Mettler TGA/DSC 3 +.

2. Characterization results

1) For FeCl during the synthesis₃·6H₂The O and the terephthalic acid are sufficiently ground so that the synthetic materials can be completely reacted in the reaction kettle, and the synthetic product is shown in figure 1.

2) The diffraction peak values 2 theta in the XRD spectrum belong to characteristic peaks of MIL-101(Fe) at 8.6 degrees, 8.9 degrees, 10.2 degrees, 10.6 degrees, 16.4 degrees, 19.5 degrees and 21.5 degrees. As shown in FIG. 2a, by comparing diffraction peaks of XRD spectrum, it is clearly seen that MIL-101(Fe) is successfully constructed, and silver ions have been successfully loaded into MIL-101(Fe), and MOFs of a bimetal structure, namely, MIL-101(Fe) @ Ag, is synthesized as a target product. With the addition of silver nitrate, the characteristic peaks of XRD appeared to be gradually reduced, namely, the structure of 20% MIL-101(Fe) @ Ag is proved to be changed by the added silver nitrate. When AgNO is used₃When the amount of (B) is 20%, the occurrence of characteristic peaks is minimized. (Fourier infrared determines the type of the functional group of the sample according to the position of the functional group, and whether the synthesized product is the required substance can be known by comparing with MIL-101 (Fe))

As shown in FIG. 3, it can be seen that the distance from the center of the lens to the center of the lens is 751cm^-1The C-H bond on the benzene ring is also remained at 1396cm^-1And 1583cm^-1Is characterized by symmetric and asymmetric vibration of carboxyl (-COO-), and 1680cm^-1The characteristic peak at (a) is then related to the presence of C ═ O bonds in the free carboxyl groups, indicating the presence of a continuous dicarboxylic linkage. Again further illustrates the presence of MIL-101(Fe) in the IR spectrum loaded with 20% silver ion. SEM image discovery of weakly magnetic nanoparticlesThe appearance is a composite cubic crystal particle, the crystal appearance is regular, and the three-dimensional structure is shown in figure 4.

As shown by the zeta potential and the nano-particle size test results in FIGS. 5a and b, 20% MIL-101(Fe) @ Ag has a zeta potential of 34.2mV, a particle size of about 382.5nm, and uniform particle distribution.

The thermogravimetric analysis method is a means for judging the thermal stability of a substance by observing the mass change of a sample along with the temperature under a heated state. As can be seen from fig. 6, the Thermogravimetric (TG) curve of the product obtained in example 1 can be roughly divided into three stages. The first stage is carried out at 30-280 ℃, and the weight loss of the sample at the stage is about 1-10%; in the second stage, the weight loss of the sample is maximum at 280-550 ℃, and is about 45%; the third stage is 550-650 ℃, the weight loss of the sample is less in the third stage, and the curve is gentle.

Test example two: the antibacterial effect of the nano material substance of the invention on bacteria is measured

1. Test materials

Dimethyl sulfoxide (DMSO), LB broth culture medium, agar powder, purchased from Kyork, Microbiol technologies, Inc.; ATCC 23235 Staphylococcus aureus (Staphylococc. mu. s a. mu. re. mu.s), ATCC 43894 Escherichia coli (Escherichia coli), purchased from ATCC; DMEM, pancreatin, fetal bovine serum, double antibody, PBS (1 ×), PBS for bacteria, AD293 cells.

2. Test object

The antibacterial composition with bimetal nano structure prepared in the embodiment 1 of the invention.

3. Test method

3.1 determination of bacterial growth curves:

respectively taking 10 mul of escherichia coli stock solution and staphylococcus aureus stock solution to disperse in 10mL of LB culture solution, and culturing for 12h in a constant temperature shaking incubator at 37 ℃. The bacteria were then diluted to 1X 10 with LB broth⁷CFU/mL. Mu.l of the diluted bacterial solution was taken, 20% MIL-101(Fe) @ Ag was added at concentrations of 20. mu.g/mL, 40. mu.g/mL, 60. mu.g/mL, 80. mu.g/mL, 100. mu.g/mL and 120. mu.g/mL, co-incubated at 30 ℃ and sampled at different time points, and OD was measured under a microplate reader.

2.2 plate coating experiment

Bacterial liquid (20. mu.l, 1X 10)⁷CF mu/mL), 20% MIL-101(Fe) @ Ag was added at concentrations of 20. mu.g/mL, 40. mu.g/mL, 60. mu.g/mL, 80. mu.g/mL, 100. mu.g/mL and 120. mu.g/mL, and after co-incubation at 30 ℃ for 3 hours, 10. mu.l of the diluted bacterial solution was spread on an agar plate, and the plate was placed in an incubator overnight. Finally, the number of colonies on the agar plate was counted, and the antibacterial effect of 20% MIL-101(Fe) @ Ag was evaluated according to the following formula:

survival (%) ═ CFU (experimental)/CFU (control) × 100%;

mortality (%) - (1-survival (%),

wherein CFU (experimental group) is the number of colonies in the material-treated group (the bimetal nanostructure antibacterial composition prepared in example 1), and CFU (control group) is the number of colonies in the control group.

2.3 bacterial MTT assay

Adding 20 percent MIL-101(Fe) @ Ag with concentration gradients (20 mug/mL, 40 mug/mL, 60 mug/mL, 80 mug/mL, 100 mug/mL and 120 mug/mL) into the third column to the eighth column of the detachable 96-well enzyme label plate according to the concentration gradient by using a liquid culture medium, setting the second column as a control, and adding a bacterial culture solution with the same volume; diluting Escherichia coli and Staphylococcus aureus to 1 × 10 with PBS⁷CFU/mL, adding 10 mul of bacterial liquid into each pore plate of a 96 pore plate, and dripping PBS into pores at the edge of the 96 pore plate for closing the pore plate; carrying out shake culture on a 96-well plate at 37 ℃ and 200r/min overnight; taking out the 96-well plate, observing the visible turbidity of the culture solution by naked eyes, and recording the minimum inhibitory concentration MIC (MIC is defined as the highest dilution with inhibition on growth, namely no visible turbidity); preparing 5mg/mL MTT solution by using PBS as a solvent, performing filtration sterilization by using a 0.22-micron syringe filter, replacing the bacterial culture solution in each hole with MTT-containing solution with the volume fraction of 10%, and then placing the solution into a bacterial incubator at 37 ℃ for reaction for 4 hours; taking out a 96-well plate, adding DMSO with the same volume into each well, and oscillating on a shaking table for 15min to promote full dissolution of formazan; and (3) placing the 96-well plate into an enzyme-linked immunosorbent assay instrument to measure the 492nm absorbance value, and measuring 570nm as reference.

The bacterial survival rate calculation formula is as follows: bacterial survival (%) — (absorbance value of experimental group/average absorbance value of control group) × 100%.

3. Cytotoxicity assays

Cytotoxicity of 20% MIL-101(Fe) @ Ag was performed by MTT assay. After depletion of AD293 cells by pancreatin, the cells were washed at 1X 10⁵The density of the wells was seeded in 96-well cell culture plates, which were then placed in a cell incubator (37 ℃, 5% CO)₂) Culturing in medium. After the cells on the bottom of the well plate grew to fill the bottom of the flask, the culture medium in the wells was removed, 20% MIL-101(Fe) @ Ag (100. mu.l each) was added to each well at a concentration of 3.125ug/mL, 6.25ug/mL, 12.5ug/mL, 25ug/mL, 50ug/mL, 100ug/mL, or 200ug/mL, and 4 wells were set while setting a cell blank, followed by further culturing in the incubator for 24 hours to observe the pathological Changes (CPE) of the cells.

After 24h incubation, 20. mu.l MTT solution (5mg/mL) was added to the corresponding well and incubation was continued for 4 h. After the end of the incubation, the supernatant was carefully removed, 150. mu.l of DMSO was added to each well to dissolve formazan at the bottom, the well plate was then placed on a shaker to shake the solution in the well, and finally the absorbance at 492nm was measured by a microplate reader, and the survival rate of the cells was calculated according to the following formula:

cell viability (%) - (sample well OD 492/blank well OD 492X 100%)

Third, test results

2. Test results

The test results are shown in tables 1 to 5 and FIGS. 7 to 10.

TABLE 1 bacterial growth curves (E.coli)

TABLE 2 bacterial growth curves (Staphylococcus aureus)

TABLE 3 bacterial plate coating experiment (20% MIL-101(Fe) @ Ag anti-E.coli and Staphylococcus aureus)

TABLE 4 bacterial plate coating experiment (MIL-101(Fe) against E.coli and Staphylococcus aureus)

TABLE 5 bacterial MTT assay

2.1 analysis of results:

the synthesized 20% MIL-101(Fe) @ Ag, when its concentration is less than 100ug/mL, can inhibit the growth of bacteria. Growth curves of escherichia coli and staphylococcus aureus under normal conditions clearly depict the four phases of bacterial growth: late phase, logarithmic phase, stationary phase, decline phase.

As shown in FIGS. 7a and 7b, the log phase of 20% MIL-101(Fe) @ Ag (20. mu.g/mL, 40. mu.g/mL, 60. mu.g/mL, 80. mu.g/mL, 100. mu.g/mL, 120. mu.g/mL) at various concentrations was gradually shortened while the time for the bacteria to reach the plateau phase was slowed, which also indicates that the inhibitory effects on E.coli and S.aureus were concentration-dependent. OD of untreated E.coli and S.aureus at 6 hours₆₀₀The values reached OD of 0.362 (E.coli) and 0.063 (S.aureus), with bacteria treated with 20% MIL-101(Fe) @ Ag₆₀₀In contrast, the OD of the latter was found₆₀₀The value is lower, and the inhibition effect on bacteria is more obvious with the higher concentration of 20% MIL-101(Fe) @ Ag. The OD values of the two bacteria decreased significantly as the added 20% MIL-101(Fe) @ Ag increased, which also indicates that as the concentration of 20% MIL-101(Fe) @ Ag increased,the survival condition of bacteria is worse and worse, and the antibacterial effect of the material is stronger and stronger.

2.2 As shown in FIGS. 8a and 8b, the bacteriostatic effect is more obvious with the increase of 20% MIL-101(Fe) @ Ag concentration, and the two are in direct proportion. The antibacterial performance of the synthesized product is detected by a flat plate coating method, and when the concentration of 20% MIL-101(Fe) @ Ag is 100 mug/mL, the inhibition effect on escherichia coli is obvious; even the survival rate of staphylococcus aureus is only about 10%. Experimental results show that the synthesized 20% MIL-101(Fe) @ Ag has excellent antibacterial effect. Compared with the MIL-101(Fe) without silver nitrate, the MIL-101(Fe) @ Ag antibacterial effect of the silver nitrate with 20 percent is better than that of the MIL-101 (Fe).

2.3 MTT is sensitive to bacteria, quantitative testing of formazan produced by ELISA showed that the survival rate of bacteria decreased sharply after reaching inhibitory concentration, and almost no bacteria survived at high concentration, as shown in FIGS. 9a and 9 b. At the concentration of 20% MIL-101(Fe) @ Ag of 60ug/mL, the staphylococcus aureus is remarkably inhibited, and meanwhile, the bacteriostasis condition is not steeply reduced like Escherichia coli, and the trend of gradual reduction is presented. This result is also consistent with the plate coating experiment.

2.4 As shown in FIG. 10, when AD293 cells were treated with different concentrations of 20% MIL-101(Fe) @ Ag particles, the results of MTT experiments on the cells showed no significant difference in cell viability and were maintained substantially above 90%.

The foregoing embodiments are merely illustrative of the principles and utilities of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or change the above-mentioned embodiments without departing from the spirit and scope of the present invention. Accordingly, it is intended that all equivalent modifications or changes which can be made by those skilled in the art without departing from the spirit and technical spirit of the present invention be covered by the claims of the present invention.

Claims

1. A preparation method of a bimetal nano-structure antibacterial composition is characterized by comprising the following steps:

s2: adding silver nitrate into absolute ethyl alcohol at 70 ℃, and then adding the absolute ethyl alcohol containing the silver nitrate into the turbid suspension I to obtain turbid suspension II; sealing the turbid suspension II in a stainless steel reaction kettle with a teflon lining, heating at 120 ℃ for 24 hours to obtain orange mud, and performing centrifugal separation to obtain orange mud;

2. The method of preparing a bi-metallic nanostructured antimicrobial composition according to claim 1, wherein FeCl in step S1₃·6H₂The molar ratio of O to terephthalic acid is 2: 1.

3. the method of preparing a bi-metallic nanostructured antimicrobial composition according to claim 1, wherein the N, N-dimethylformamide and FeCl in step S1₃·6H₂The dosage ratio of O is 20-40 mL: 1.351 g; the using amount ratio of the absolute ethyl alcohol to the silver nitrate in the step S2 is 5-10 mL: 0.3532 g.

4. The method for preparing a bimetal nanostructure antibacterial composition of claim 1, wherein the silver nitrate addition amount in the step S2 is FeCl₃·6H₂2-20% of the total mass of O and terephthalic acid.

5. The method for preparing a bimetal nanostructure antibacterial composition of claim 1, wherein the silver nitrate addition amount in the step S2 is FeCl₃·6H₂20 percent of the total mass of O and terephthalic acid.

6. The method for preparing a bimetal nanostructure antibacterial composition of claim 1, wherein the ultrasonic time in the step S1 is 15min and the ultrasonic power is 120W.

7. The method for preparing a bimetal nanostructure antimicrobial composition of claim 1, wherein the centrifugation speed in the steps S2 and S3 is 4000 rmp.

8. The method for preparing a bimetal nanostructured antimicrobial composition according to claim 1, wherein the orange puree is washed with DMF 1 time in the step S3; the orange paste was washed 2 times with hot ethanol at 70 ℃.

9. A bi-metallic nanostructured antimicrobial composition prepared by the method of any one of claims 1 to 8.

10. Use of the bimetallic nanostructured antimicrobial composition according to claim 9 for the preparation of an antimicrobial material.