A method for preparing an antibacterial composite film based on agar and its application

Abstract

The invention discloses a method for preparing an antibacterial composite film based on agar and its application. The preparation method includes preparing agar powder into a solution, then dispersing Ag NP@ACM‑1 therein, and after the solution is cooled and solidified, drying is performed to obtain an Ag NP@ACM‑1 film; wherein, the preparation method of Ag NP@ACM‑1 includes: preparing ACM‑1 (titanium-based MOF) into a dispersion, then adding an AgNO3 solution, and then irradiating the dispersion with a light source, centrifuging and cleaning, and finally obtaining a precipitate, which is Ag NP@ACM‑1. The antibacterial composite film prepared by this scheme not only has excellent antibacterial properties, but also has certain mechanical properties and pliable strength, and still has a good antibacterial effect after recovery. At the same time, the composite film synthesis process in the present invention is simple, green and environmentally friendly, low in cost, highly repeatable and operable, and has a very broad application prospect.

Description

Technical Field

[0001] The invention relates to the fields of pharmaceutical chemistry technology and food technology, and in particular to a method for preparing an agar-based antibacterial composite film and application thereof. Background Art

[0002] As people's living standards continue to improve, in terms of food preservation, people's requirements for food freshness and safety are constantly increasing. At the same time, the recyclability, degradation and environmental protection of food coatings are also another hot topic of concern. Since nanosilver has strong antibacterial properties against bacteria and fungi, its advantages are gradually emerging and are also widely used. As a new type of antibacterial material, metal-organic frameworks not only have broad-spectrum antibacterial activity, but also include the advantages of adjustable structure, large specific surface area, and easy synthesis. It is precisely because of these advantages that metal-organic framework materials have been noticed by scientists and introduced for in-depth research.

[0003] In view of this, the present invention has developed a nanosilver-loaded metal-organic framework material, which is mixed with agar to form an antibacterial composite film for use in food preservation, so that the growth of microorganisms in food can be inhibited, thereby achieving the effect of extending the food preservation time. At the same time, the composite antibacterial film also has the advantages of being recyclable and reused, and being green and environmentally friendly, which will bring positive practical significance and provide new research ideas and directions for food preservation. Summary of the invention

[0004] In view of this, the object of the present invention is to propose a method for preparing an agar-based antibacterial composite film which has good antibacterial properties, is green and environmentally friendly, can be recycled repeatedly, and has good structural strength, and its application.

[0005] In order to achieve the above technical objectives, the technical solution adopted by the present invention is:

[0006] A method for preparing an agar-based antibacterial composite film, comprising: preparing agar powder into a solution, dispersing AgNP@ACM-1 therein, and drying the solution after the solution is cooled and solidified to obtain an AgNP@ACM-1 film;

[0007] The preparation method of Ag NP@ACM-1 includes: dispersing ACM-1 in a solvent to prepare a solution, then adding an AgNO3 solution, irradiating the dispersion with a light source, centrifuging, washing, and finally obtaining a precipitate, which is Ag NP@ACM-1;

[0008] In addition, the preparation method of ACM-1 comprises: H4TBAPy, propionic acid and Ti(O iPr)4 is dispersed in a mixed solution of N,N-dimethylacetamide and chlorobenzene, then ultrasonically mixed, heated for reaction, and finally centrifuged to obtain the solid product produced by the reaction, which is then washed to obtain a solid product (orange-yellow solid), namely ACM-1, which is a titanium-based MOF.

[0009] As a possible implementation mode, further, in the preparation method of ACM-1 of this scheme, in the mixed system, the concentration of H4TBAPy is greater than 15 mg / mL, the concentration of propionic acid is greater than 15 mg / mL, and the concentration of Ti(O i The concentration of Pr)4 is greater than 15 mg / mL, the time of ultrasonic mixing is greater than 5 min, the temperature of the heating reaction is greater than 100°C, the time of the heating reaction is greater than 10 h, the speed of the centrifugation is greater than 2000 rpm / min, and the washing is performed by using at least one of N,N-dimethylacetamide, methanol, ethanol, and acetone. The precipitate obtained by centrifugation is washed more than twice to obtain ACM-1.

[0010] As a preferred embodiment, in the preparation method of ACM-1 of this scheme, in the mixed system, the concentration of H4TBAPy is 20-30 mg / mL, the concentration of propionic acid is 20-30 mg / mL, and the concentration of Ti(O i The concentration of Pr)4 is 20-30 mg / mL. In the mixed solution, N, N-dimethylacetamide and chlorobenzene are added according to V DEF :V 氯苯 =1 to 3:1 ratio mixing, the ultrasonic mixing time is 20 to 40 minutes, the heating reaction temperature is 130 to 180 ° C, the heating reaction time is 15 to 30 hours, the centrifugal speed is 6000 to 12000 rpm / min, the washing is carried out by at least one of N, N-dimethylacetamide, methanol, ethanol, and acetone, and the precipitate obtained by centrifugation is washed 3 to 5 times.

[0011] As a possible implementation mode, further, after the agar powder described in this scheme is made into a solution, its concentration is greater than 1 mg / mL, and after the Ag NP@ACM-1 is dispersed in the solution, its concentration is greater than 0.1 mg / mL;

[0012] The agar powder is added to water and then prepared into a solution under the conditions of a heating temperature greater than 70°C and a heating stirring time greater than 0.1h. The Ag NP@ACM-1 is dispersed in the solution under the condition of an ultrasonic treatment greater than 0.1h. The drying temperature is greater than 30°C and the drying time is greater than 4h.

[0013] As a possible implementation mode, further, in the preparation method of Ag NP@ACM-1 of this scheme, the mass ratio of ACM-1 to AgNO3 is 5 to 20:1, the concentration of the AgNO3 solution is greater than 2 mg / mL, the dropwise addition rate of the AgNO3 solution is greater than 0.5 mL / min, and the solvent is at least one of water, methanol, ethanol, N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide.

[0014] As a possible implementation mode, further, in the preparation method of Ag NP@ACM-1 of this scheme, the light source is a xenon lamp, an LED lamp or an incandescent lamp, the light source irradiates the dispersion for greater than 0.2 h, the centrifugal speed is greater than 2000 rpm / min, and the precipitate obtained by centrifugation is washed with at least one of N,N-dimethylacetamide, methanol, ethanol, and acetone, and the washing number is more than 2 times.

[0015] As a preferred embodiment, preferably, after the agar powder in this solution is made into a solution, its concentration is 10-100 mg / mL, and after the Ag NP@ACM-1 is dispersed in the solution, its concentration is 0.1-10 mg / mL;

[0016] The agar powder is added to water and heated at 80 to 120° C. for 0.5 to 2 hours to form a solution, the Ag NP@ACM-1 is dispersed in the solution under ultrasonic treatment for 0.2 to 1 hour, the drying temperature is 30 to 100° C., and the drying time is 4 to 24 hours;

[0017] As a preferred embodiment, preferably, in the preparation method of Ag NP@ACM-1 of this scheme, the mass ratio of ACM-1 to AgNO3 is 10:1, the concentration of the AgNO3 solution is 10 mg / mL, the dropwise addition rate of the AgNO3 solution is 1-2 mL / min, and the solvent is a mixture of water and ethanol in a volume ratio of 2:1;

[0018] As a preferred embodiment, preferably, the light source in this scheme is a xenon lamp, the light source irradiates the dispersion for 0.5 to 2 hours, the centrifuge speed is 10000 rpm / min, and the precipitate obtained by centrifugation is washed with ethanol for 3 to 5 times.

[0019] Based on the above, the present invention also provides an antibacterial composite film, which is prepared by the preparation method described above.

[0020] Based on the above, the present invention also provides a method for recycling an antibacterial composite film, which is used for the recycling of the antibacterial composite film described above. The recycling method comprises: adding the recovered antibacterial composite film to a solution at a preset temperature for heating and stirring, and after the antibacterial composite film is completely melted, pouring it into a container, and after it is cooled and solidified, placing it in an oven for heating and drying to complete the recycling.

[0021] As a preferred embodiment, the antibacterial composite film of this scheme is preferably heated to a temperature above 70°C, the heating and stirring time is greater than 0.1h, and the oven is heated and dried at a temperature greater than 30°C, and the drying time is greater than 4h.

[0022] As a preferred embodiment, the antibacterial composite film of this scheme is preferably heated to a temperature of 80-120°C, the heating and stirring time is 0.2-1h, and the oven is heated and dried at a temperature of 30-100°C, and the drying time is 4-24h.

[0023] Based on the above, the present invention also provides a food coating film, characterized in that it includes the antibacterial composite film described above.

[0024] By adopting the above technical scheme, the present invention has the following beneficial effects compared with the prior art: the present scheme cleverly utilizes agar, which is cheap, widely available, non-toxic, pollution-free, edible and green and environmentally friendly, as a connector, and after making it into a solution, mixes it with the antibacterial material Ag NP@ACM-1 to form an antibacterial composite film. The antibacterial composite film has excellent antibacterial properties, good mechanical properties and flexibility, and it also has the advantages of being recyclable and reusable, and being green and environmentally friendly. When it is used for food coating, it plays a very important role in sterilization and even inhibition of bacteria, and blocking the spread of bacteria and viruses. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0026] Figure 1 TEM characterization image of ACM-1 in Example 1 of the present invention;

[0027] Figure 2 This is a SEM characterization image of the nano-Ag NP@ACM-1 prepared in Example 1 of the present invention;

[0028] Figure 3This is a TEM characterization image of the nano-Ag NP@ACM-1 prepared in Example 1 of the present invention;

[0029] Figure 4 is the XRD characterization diagram of ACM-1 and Ag NP@ACM-1 of Example 1 of the present invention;

[0030] Figure 5 This is the SEM image of the original film surface;

[0031] Figure 6 This is a SEM image of the surface of the antibacterial composite film prepared by the present invention;

[0032] Figure 7 is the contact angle of the original film surface;

[0033] Figure 8 The contact angle of the surface of the antibacterial composite film prepared by the present invention;

[0034] Fig. 9 The size of the inhibition zone of the antibacterial composite film prepared by the present invention and the antibacterial composite film after recovery against Escherichia coli and Staphylococcus aureus;

[0035] Fig.10 The mechanical properties of the antibacterial composite film prepared by the present invention. DETAILED DESCRIPTION

[0036] The present invention will be further described in detail below in conjunction with the accompanying drawings and examples. It is particularly noted that the following examples are only used to illustrate the present invention, but are not intended to limit the scope of the present invention. Similarly, the following examples are only partial embodiments of the present invention rather than all embodiments, and all other embodiments obtained by those of ordinary skill in the art without creative work are within the scope of protection of the present invention.

[0037] Example 1

[0038] This embodiment provides a method for preparing a metal-organic framework material, which comprises:

[0039] Weigh 100 mg of ACM-1 and add 15 mL of water-ethanol mixed solution (V H2O :V EtOH =2:1), and then 1 mL of 10 mg / mL AgNO3 solution was added dropwise at a dropping speed of 1 mL / min. The suspension was then irradiated under a xenon lamp light source for 60 min, followed by centrifugation and washing to obtain a dark yellow solid, namely Ag NP@ACM-1.

[0040] The preparation method of ACM-1 used in this embodiment is as follows:

[0041] 48 mg H4TBAPy, 42 μL propionic acid and 41 μL Ti(O i Pr)4 was dispersed in 2 mL of a mixed solution of N, N-dimethylacetamide and chlorobenzene (V DEF :V 氯苯 =1:1), then ultrasonically mixed for 30 minutes, heated at 150°C for 24 hours for reaction, and finally centrifuged at 10000 rpm / min to obtain the solid produced by the reaction, washed twice with N, N-dimethylacetamide and once with anhydrous ethanol to obtain a solid product (orange-yellow solid), thereby preparing ACM-1. The TEM characterization image of ACM-1 is shown in Figure 1 shown.

[0042] The Ag NP@ACM-1 prepared in this example was subjected to SEM and TEM tests, and the results were as follows: Figure 2 , Figure 3 As shown, the XRD characterization of ACM-1 and Ag NP@ACM-1 prepared in this example Figure 4 shown.

[0043] Example 2

[0044] Based on Example 1, this example further provides an application of Ag NP@ACM-1 in an antibacterial film, that is, this example provides a method for preparing an antibacterial composite film based on agar, which comprises:

[0045] Add 1 g of agar powder to 50 ml of ultrapure water, heat and stir at 100 °C for 1 hour to form a clear and transparent solution, then add 50 mg of Ag NP@ACM-1, and use ultrasound to evenly distribute the material in the agar solution. Pour the mixed solution into a culture dish, and after the solution solidifies, heat it in a 35 °C oven for 24 hours to obtain the Ag NP@ACM-1 film.

[0046] In this embodiment, agar powder is a binder that allows Ag NP@ACM-1 and agar to be fully mixed; ultrapure water is a dispersant that allows Ag NP@ACM-1 to be evenly dispersed in ultrapure water. However, it should be noted that too much agar powder will cause the particles to agglomerate, and too much ultrapure water will make the antibacterial film components too thin.

[0047] In order to facilitate the comparison of the structure of the prepared film, this embodiment also prepared a film with the same process parameters but without adding Ag NP@ACM-1 as a control group according to the above preparation method and parameters, that is, the original film of the film, which was prepared by using agar as the film-forming material, without adding Ag NP@ACM-1, and other casting components and formulas according to the above embodiment, to prepare the original antibacterial film, specifically:

[0048] Add 1g agar powder to 50ml ultrapure water, heat and stir at 100℃ for 1 hour to form a clear and transparent solution, then perform ultrasonic treatment to evenly distribute the components of the agar solution, pour the mixed solution into a culture dish, and after the solution solidifies, place it in a 35℃ oven and heat for 24 hours to obtain the original antibacterial film.

[0049] The original film and Ag NP@ACM-1 film were subjected to SEM examination, and the results were as follows: Figure 5 , Figure 6 shown.

[0050] In addition, the contact angles of the original film and the Ag NP@ACM-1 film were tested and compared. The results are shown in Figure 2. Figure 7 , Figure 8 As shown, it can be seen that the contact angle of the original film is 65.97°, while the contact angle of the Ag NP@ACM-1 film of this scheme is 48.09°.

[0051] In the present application, the Ag NP@ACM-1 film has the technical effect of being recyclable and reusable. In addition, its recycling method is: after the film is recycled, it is added to 100°C boiling water and heated with stirring. After the film is completely melted, it is poured into a culture dish while hot, and after solidification, it is placed in a 35°C oven and heated for 24 hours.

[0052] Antibacterial performance test

[0053] The antibacterial performance test mainly uses the inhibition zone method to test the antibacterial effect of the film, and selects E. coli and S. aureus as the research objects. Fig. 9 As well as the statistics of the average inhibition zone diameters of the newly prepared or recycled antibacterial films in Table 1, it can be seen that the antibacterial films have good antibacterial properties against E. coli and S. aureus before and after illumination.

[0054] Table 1 Zone of inhibition average diameter of Ag NP@ACM-1 membrane

[0055]

[0056] Combining Table 1 and Fig. 9 As shown in the figure, due to the unique cell wall structure of Gram-positive bacteria, the photodynamic-chemical synergistic antibacterial effect of the film on S. aureus is more obvious. Comparing the size of the inhibition zone of the new film and the recycled film, the difference between the two is not much. The above experiments prove that the film prepared by the above method can not only be recycled, but also the recycled film still has good antibacterial properties.

[0057] In order to verify the mechanical properties and flexibility of the Ag NP@ACM-1 film prepared by this scheme, this embodiment folded it several times and then unfolded it to observe the appearance of the Ag NP@ACM-1 film. Fig.10 It can be seen that the Ag NP@ACM-1 film did not tear or break after being folded multiple times. It can be seen that the Ag NP@ACM-1 film of this scheme has certain mechanical strength and flexibility, and it has a good application foundation and prospect.

[0058] The above descriptions are only some embodiments of the present invention, and are not intended to limit the protection scope of the present invention. Any equivalent device or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for preparing an antibacterial composite film based on agar, characterized in that: It includes: Agar powder is made into a solution, and then Ag NP@ACM-1 is dispersed in the solution, and after the solution is cooled and solidified, a drying process is performed to obtain an Ag NP@ACM-1 film, wherein the Ag NP@ACM-1 film is used for food coating; Wherein, after the agar powder is made into a solution, its concentration is 10-100 mg / mL, and after the Ag NP@ACM-1 is dispersed in the solution, its concentration is 0.1-10 mg / mL; The agar powder is added to water and heated at a temperature greater than 70°C and heated and stirred for more than 0.1 h to prepare a solution, the Ag NP@ACM-1 is dispersed in the solution under ultrasonic treatment for more than 0.1 h, the drying temperature is 30-100°C, and the drying time is 4-24 h; The preparation method of Ag NP@ACM-1 includes: dispersing ACM-1 in a solvent, then adding AgNO3 solution, irradiating the dispersion with a light source, centrifuging, washing, and finally obtaining a precipitate, which is Ag NP@ACM-1; The preparation method of ACM-1 comprises: reacting H4TBAPy, propionic acid and Ti(O i Pr)4 is dispersed in a mixed solution of N, N-dimethylacetamide and chlorobenzene, then ultrasonically mixed, heated for reaction, and finally centrifuged to obtain the solid produced by the reaction, and then washed to obtain a solid product, namely ACM-1; In the preparation method of ACM-1, in the mixed system, the concentration of H4TBAPy is 20-30 mg / mL, the concentration of propionic acid is 20-30 mg / mL, and the concentration of Ti(O i The concentration of Pr)4 is 20-30 mg / mL. In the mixed solution, N,N-dimethylacetamide and chlorobenzene are added according to V DEF :V 氯苯 =1 to 3:1, the ultrasonic mixing time is 20 to 40 min, the heating reaction temperature is 130 to 180 ° C, the heating reaction time is 15 to 30 h, the centrifugal speed is 6000 to 12000 rpm / min, the washing is carried out by using at least one of N, N-dimethylacetamide, methanol, ethanol, and acetone, and the precipitate obtained by centrifugation is washed more than twice to obtain ACM-1.

2. The method for preparing an antibacterial composite film based on agar according to claim 1, characterized in that: In the preparation method of ACM-1, the precipitate obtained by centrifugation is washed 3 to 5 times.

3. The method for preparing an antibacterial composite film based on agar according to claim 1, characterized in that: In the preparation method of Ag NP@ACM-1, the mass ratio of ACM-1 to AgNO3 is 5 to 20:1, the concentration of the AgNO3 solution is greater than 2 mg / mL, the drop rate of the AgNO3 solution is greater than 0.5 mL / min, and the solvent is at least one of water, methanol, ethanol, N,N-dimethylformamide, N,N-dimethylacetamide, and dimethyl sulfoxide; The light source is a xenon lamp, an LED lamp or an incandescent lamp, the light source irradiates the dispersion for a time period greater than 0.2 h, the centrifugal speed is greater than 2000 rpm / min, and the precipitate obtained by centrifugation is washed with at least one of N,N-dimethylacetamide, methanol, ethanol, and acetone, and the washing frequency is more than 2 times.

4. The method for preparing an antibacterial composite film based on agar according to claim 1, characterized in that: After the agar powder is added to water, a solution is prepared under the conditions of a heating temperature of 80 to 120° C. and a heating and stirring time of 0.5 to 2 h, and the AgNP@ACM-1 is dispersed in the solution under the conditions of an ultrasonic treatment time of 0.2 to 1 h; In the preparation method of Ag NP@ACM-1, the mass ratio of ACM-1 to AgNO3 is 10:1, the concentration of the AgNO3 solution is 10 mg / mL, the drop rate of the AgNO3 solution is 1-2 mL / min, and the solvent is a mixture of water and ethanol at a volume ratio of 2:1; The light source is a xenon lamp, the light source irradiates the dispersion for 0.5 to 2 h, the centrifugal speed is 10000 rpm / min, and the precipitate obtained by centrifugation is washed with ethanol for 3 to 5 times.

5. An antibacterial composite film, characterized in that: The compound is prepared by the preparation method according to any one of claims 1 to 4.

6. A food coating film, characterized in that: It includes the antibacterial composite film as described in claim 5.

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