Preparation method of a Ce6-mediated photodynamic sterilization film and application thereof to fresh food preservation

Abstract

The application relates to the technical fields of biological medicine, nanomaterials and food safety, and particularly relates to a preparation method of a Ce6-mediated photodynamic sterilization film and application of the Ce6-mediated photodynamic sterilization film to fresh food preservation. The Ce6-mediated photodynamic sterilization film is prepared by the following method: yttrium nitrate, europium nitrate and bismuth nitrate are dissolved in deionized water, and then mixed with sodium vanadate; the mixed solution is subjected to hydrothermal reaction in a polytetrafluoroethylene reaction kettle; the product after the hydrothermal reaction is mixed with Ce6 and centrifuged to obtain Ce6-mediated nanomaterials; the nanomaterials have photosensitizer activity and can be used for inhibiting bacteria and fungi; the nanomaterials are dissolved in CMC, stirred and dried on a glass plate to obtain the Ce6-mediated photodynamic sterilization film. The Ce6-mediated photodynamic sterilization film generates active oxygen under ultraviolet light and has UV blocking function, can be used for photodynamic antibacterial and fresh food preservation, and realizes the double effects of UV sterilization and food loss prevention.

Description

Technical Field

[0001] This invention relates to the fields of polymer materials, biomedicine and nanomaterials, specifically to a method for preparing a Ce6-mediated photodynamic bactericidal film and its application in the preservation of fresh food. Background Technology

[0002] Photodynamic sterilization is a novel method in which photosensitizers, under irradiation with light of a suitable wavelength, generate reactive oxygen species (ROS) through energy transfer or electron transfer, thereby oxidizing lipids, proteins, and nucleic acids within microorganisms and leading to their death. Photodynamic sterilization is a multi-target process that does not lead to drug resistance in microorganisms, and it does not produce high heat or harmful substances, making it a safe cold sterilization method. In recent years, research on photodynamic sterilization in food safety has increased significantly. Dihydroporphyrin E6 (Ce6), derived from the refined extraction and chemical modification of chlorophyll, is considered a photosensitizer with excellent properties. Ce6 exhibits superior photodynamic response, low dark-environment toxicity, and rapid in vivo metabolism. In photodynamic sterilization, Ce6 is activated under light of a predetermined wavelength, converting photon energy into photochemical reactions to generate ROS. These ROS are capable of oxidizing intracellular biomolecules, thereby achieving a bactericidal effect. However, Ce6 is hydrophobic due to the presence of π-conjugated domains in its molecular structure. When applied directly in an aqueous physiological environment, it easily aggregates, leading to a significant reduction in reactive oxygen species yield and thus affecting the photodynamic bactericidal effect. Nanomaterials typically possess large specific surface areas, high chemical reactivity, and are easily absorbed by organisms. Using nanocarriers can, to some extent, solve the problems of poor water solubility, low targeting, and easy aggregation that occur when photosensitizers are used alone.

[0003] Ultraviolet (UV) light has bactericidal properties and can penetrate the surface tissue of fresh food, making it a commonly used sterilization method. However, high-dose UV irradiation can cause browning on the surface of meat, as well as protein and fat oxidation, thus affecting the shelf life of food. Utilizing nanomaterials to convert UV light into visible light using the principle of light conversion is a feasible method to reduce the damage of UV light to food. Furthermore, using the converted visible light can enhance the antibacterial effect, further contributing to extending the shelf life of food. Currently, there are few reports on nanomaterials utilizing the light conversion properties of UV light.

[0004] In recent years, with the pursuit of high-quality food and extended shelf life, research on food packaging has gradually increased. Among them, antimicrobial films for food have attracted attention as an innovative approach. These films, combined with active substances, can both physically isolate and inhibit the growth of microorganisms, thereby improving food safety and reducing waste. Notably, the incorporation of nanomaterials into antimicrobial films for food has become a new trend, bringing greater improvements to their antimicrobial performance and promoting the further development of sustainable packaging.

[0005] Strawberries are perennial plants belonging to the Rosaceae family, rich in vitamins, folic acid, and polyphenols. However, strawberries are a fruit with a pronounced post-ripening characteristic and a relatively short shelf life. During storage, strawberries are often susceptible to diseases such as gray mold caused by Botrytis cinerea. Under ultraviolet light during storage, they rapidly dehydrate and undergo oxidation, leading to color changes—key factors affecting their freshness. Finding effective post-harvest treatment and storage methods for strawberries to inhibit mold growth, prevent rot, and prevent oxidative changes has become a focus of academic research. Chilled chicken is popular due to its unique flavor, delicate texture, and nutritional value. Although ultraviolet light can inhibit the growth of pathogenic microorganisms on the surface of chilled chicken to some extent, prolonged exposure to ultraviolet light causes oxidation of fat and myoglobin, and may also result in some water loss, thus reducing its market value. Generally, the shelf life of chilled chicken is about two days. Therefore, finding effective strategies to extend the shelf life of chilled chicken is particularly crucial. While commonly used meat preservatives, such as sodium lactate, potassium sorbate, and sodium citrate, do have significant antibacterial effects, long-term or excessive intake may have adverse effects on the human body. Therefore, developing a safe and environmentally friendly antibacterial film that can convert ultraviolet light into visible light and kill both bacteria and fungi is of significant academic and practical value for ensuring the storage quality of fruits, vegetables, and chilled chicken and extending their shelf life. Summary of the Invention

[0006] The purpose of this invention is to overcome the defects of the prior art and provide a method for preparing a Ce6 (i.e., dihydroporphyrin e6) light-mediated photodynamic bactericidal film that is simple to synthesize, has high phototoxicity, requires a short irradiation time, and can block a certain amount of ultraviolet light, thereby preventing excessive ultraviolet light irradiation from damaging fresh food, and its application in the preservation of fresh food.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] One of the objectives of this invention is to provide a Ce6-mediated photodynamic bactericidal nanomaterial, which specifically includes a YVO4:Bi,Eu nanoparticle carrier and a photosensitizer Ce6 carried thereon, wherein the mass ratio of the YVO4:Bi,Eu nanoparticle carrier to the photodynamic drug Ce6 is 1:0.1 to 3.

[0009] Preferably, the Ce6 molecule is a conjugated porphyrin ring, mainly consisting of a conjugated porphyrin ring skeleton formed by four α-carbon atoms of pyrrole rings linked by four methine (-CH=) bridges. The π→π* transitions of the porphyrin ring contribute to the light absorption of Ce6 at 405 nm and 650 nm.

[0010] Preferably, YVO4:Bi,Eu nanoparticles produce 640nm red light under 320nm ultraviolet light irradiation, which overlaps with the absorption spectrum of Ce6. Furthermore, the particle size of the YVO4:Bi,Eu nanoparticles is 15–200nm. The nanoscale particle size obtained by loading the photosensitizer Ce6 onto YVO4:Bi,Eu nanoparticles helps to improve the water solubility of Ce6, prevents aggregation, and thus increases the phototoxicity of the photosensitizer Ce6.

[0011] One objective of this invention is to provide a method for preparing Ce6-mediated photodynamic bactericidal nanomaterials, the method comprising the following steps:

[0012] S1. Yttrium nitrate, europium nitrate and bismuth nitrate are dissolved in deionized water and then mixed with sodium vanadate solution.

[0013] S2. Transfer the mixed solution to a polytetrafluoroethylene reactor for hydrothermal reaction;

[0014] S3. The product obtained after centrifugation is dissolved in deionized water and mixed with Ce6 solution to obtain a Ce6-mediated photodynamic bactericidal nanomaterial.

[0015] Preferably, the mass ratio of yttrium nitrate, europium nitrate and bismuth nitrate is 1:0.01-10:0.01-10.

[0016] Preferably, the concentration of the sodium vanadate solution is 0.1–10 mg / mL.

[0017] Preferably, the volume ratio of the deionized water to the sodium vanadate solution is 0.1 to 10:1.

[0018] Preferably, the heating temperature of the hydrothermal reaction is 160–230°C, and the heating time is 2–10 h.

[0019] Preferably, the centrifugation speed is 4000-12000 rpm / min and the centrifugation time is 4-20 min.

[0020] Preferably, the Ce6 solution concentration is 2–20 mol / L and the Ce6 solution volume is 1–20 mL.

[0021] The second objective of this invention is to provide a method for preparing a Ce6-mediated photodynamic bactericidal film, the preparation method specifically including the following steps:

[0022] S1. Dissolve the photodynamic bactericidal nanoparticles prepared above in a CMC solution, mix them, pour the mixture onto a glass plate, and dry it to obtain the Ce6-mediated photodynamic bactericidal film.

[0023] Preferably, the mass ratio of the photodynamic bactericidal nanoparticles to the CMC solution is 1:5 to 20.

[0024] Preferably, the concentration of the CMC solution is 0.001 to 0.5 mg / mL.

[0025] Preferably, the mixing time is 0.1 to 12 hours.

[0026] Preferably, the drying temperature is 10–50°C and the drying time is 12–48 h.

[0027] The third objective of this invention is to provide an application of Ce6-mediated photodynamic bactericidal nanomaterials in inhibiting the growth of bacteria and fungi.

[0028] Compared with existing technologies, this invention uses YVO4:Bi,Eu nanoparticles as a carrier and loads the photosensitizer Ce6. During photodynamic sterilization, the YVO4:Bi,Eu nanoparticles absorb ultraviolet light and generate red light. This red light is utilized by Ce6 to generate reactive oxygen species, increasing the phototoxicity of Ce6 and improving the photodynamic sterilization effect. The YVO4:Bi,Eu-loaded Ce6 nanoparticles exhibit strong bactericidal effects against bacteria such as Staphylococcus aureus and fungi such as Botrytis cinerea.

[0029] The fourth objective of this invention is to provide an application of Ce6-mediated photodynamic antibacterial film in the preservation of fresh food.

[0030] The YVO4:Bi,Eu-loaded Ce6 nanoparticles used in this invention possess strong antibacterial properties. These nanoparticles are immobilized in a CMC membrane to prepare a photodynamic sterilization film, which can be applied to the preservation of fresh food. Furthermore, this photodynamic sterilization film can not only block excessive ultraviolet radiation from damaging the food without contacting it, but also generate reactive oxygen species that can achieve a certain sterilization effect on the fresh food. The highly efficient, safe, and environmentally friendly photodynamic sterilization film constructed in this invention can extend the shelf life of fresh food. Attached Figure Description

[0031] Figure 1 Scanning electron microscope images of Ce6-mediated photodynamic bactericidal nanoparticles and Ce6-mediated photodynamic bactericidal films.

[0032] Figure 2 The emission spectrum of YVO4:Bi,Eu nanoparticles under 320 nm excitation.

[0033] Figure 3 The image shows the UV absorption curve of Ce6.

[0034] Figure 4The curve shows the relationship between singlet oxygen generated by Ce6-mediated photodynamic bactericidal nanoparticles under 360nm ultraviolet light irradiation and time.

[0035] Figure 5 The antibacterial effect of photodynamic bactericidal films on Staphylococcus aureus.

[0036] Figure 6 The antibacterial effect of photodynamic bactericidal films against Staphylococcus aureus

[0037] Figure 7 The application effect of photodynamic antibacterial film in strawberry preservation

[0038] Figure 8 The application effect of photodynamic sterilization film in chicken preservation Detailed Implementation

[0039] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0040] A Ce6-mediated photodynamic bactericidal nanomaterial specifically includes a YVO4:Bi,Eu nanoparticle carrier and a photosensitizer Ce6 carried thereon, wherein the mass ratio of the YVO4:Bi,Eu nanoparticle carrier to the photodynamic drug Ce6 is 1:0.1-3.

[0041] As a preferred embodiment of the above scheme, the Ce6 molecule is a conjugated porphyrin ring, mainly consisting of a conjugated porphyrin ring skeleton formed by four α-carbon atoms of pyrrole rings connected by four methine (-CH=) bridges. The π→π* transition of the porphyrin ring contributes to the light absorption of Ce6 at 405 nm and 650 nm.

[0042] As a preferred embodiment of the above-mentioned scheme, the YVO4:Bi,Eu nanoparticles produce 640nm red light under 320nm ultraviolet light irradiation, which overlaps with the absorption spectrum of Ce6. Furthermore, the particle size of the YVO4:Bi,Eu nanoparticles is 15–200nm.

[0043] A method for preparing a Ce6-mediated photodynamic bactericidal film, the method comprising the following steps:

[0044] S1. Yttrium nitrate, europium nitrate and bismuth nitrate are dissolved in deionized water and then mixed with sodium vanadate solution.

[0045] S2. Transfer the mixed solution to a polytetrafluoroethylene reactor for hydrothermal reaction;

[0046] S3. The product obtained after centrifugation is dissolved in deionized water and mixed with Ce6 solution to obtain a Ce6-mediated photodynamic bactericidal nanomaterial.

[0047] The mass ratio of yttrium nitrate, europium nitrate and bismuth nitrate is 1:0.01-10:0.01-10.

[0048] The concentration of the sodium vanadate solution is 0.1–10 mg / mL.

[0049] The volume ratio of the deionized water to the sodium vanadate solution is 1:0.1 to 10.

[0050] The hydrothermal reaction is heated at a temperature of 160–230°C for 2–10 hours.

[0051] The centrifugation speed is 4000-12000 rpm / min, and the centrifugation time is 4-20 min.

[0052] The Ce6 solution concentration is 2–20 mol / L, and the Ce6 solution volume is 1–20 mL.

[0053] A method for preparing a Ce6-mediated photodynamic bactericidal film, the method specifically comprising the following steps:

[0054] S1. Dissolve the photodynamic bactericidal nanoparticles prepared above in a CMC solution, mix them, pour the mixture onto a glass plate, and dry it to obtain the Ce6-mediated photodynamic bactericidal film.

[0055] The mass ratio of the photodynamic bactericidal nanoparticles to the CMC solution is 1:5 to 20.

[0056] The concentration of the CMC solution is 0.001–0.5 mg / mL.

[0057] The mixing time is 0.1 to 12 hours.

[0058] The drying temperature is 30–80℃, and the drying time is 12–48 hours.

[0059] Application of Ce6-mediated photodynamic bactericidal nanomaterials in inhibiting the growth of bacteria and fungi.

[0060] This paper presents a Ce6-mediated photodynamic bactericidal nanomaterial with a particle size distribution ranging from 15 to 200 nm. Under 320 nm ultraviolet light irradiation, YVO4:Bi,Eu generates red light, which is transferred to Ce6, thereby producing reactive oxygen species (ROS) with extremely strong oxidizing properties. Based on the antibacterial properties of ROS, it can be applied to the inhibition of bacteria and fungi.

[0061] Application of a Ce6-mediated photodynamic antibacterial film in the preservation of fresh food.

[0062] This invention provides a Ce6-mediated photodynamic bactericidal film, which has a simple preparation process and strong phototoxicity. The Ce6-mediated photodynamic bactericidal nanomaterials have a particle size distribution range of 15–200 nm. Under 320 nm ultraviolet light irradiation, YVO4:Bi,Eu generates red light, which is transferred to Ce6, thereby producing reactive oxygen species with extremely strong oxidizing properties. The Ce6-mediated photodynamic bactericidal film can achieve bactericidal effect by blocking ultraviolet light while utilizing ultraviolet light to generate reactive oxygen species. Based on its photosensitizer properties, it can be used in photodynamic antibacterial and fresh food preservation fields.

[0063] The present invention will be further described in detail below with reference to specific embodiments. The following embodiments are not intended to limit the present invention, but only to illustrate the present invention. Unless otherwise specified, the experimental methods used in the following embodiments are generally performed under conventional conditions. Unless otherwise specified, the materials and reagents used in the following embodiments are commercially available.

[0064] Example 1

[0065] A method for preparing a Ce6-mediated photodynamic bactericidal film includes the following steps:

[0066] Yttrium nitrate, europium nitrate, and bismuth nitrate were dissolved in deionized water at a ratio of 1:0.3:0.3, and then mixed with sodium vanadate solution (1 mg / mL) at a ratio of 1:0.5. The mixed solution was transferred to a 100 mL polytetrafluoroethylene reactor and placed in an oven at 200 °C for 6 h. After the reaction, the product obtained by centrifugation (10000 rpm / min, 8 min) was dissolved in deionized water and mixed with Ce6 solution (5 mol / L, 2 mL) to obtain a Ce6-mediated photodynamic bactericidal nanomaterial. The centrifuged product was then dissolved in CMC solution (0.05 mg / mL) at a mass ratio of 1:10, mixed for 5 h, poured onto a glass plate, and dried (30 °C, 24 h) to obtain the Ce6-mediated photodynamic bactericidal film. Scanning electron microscopy of the Ce6-mediated photodynamic bactericidal nanomaterials and Ce6-mediated photodynamic bactericidal films is shown below. Figure 1 As shown in the figure, the particle size of the Ce6-mediated photodynamic bactericidal nanoparticles ranges from 15 to 200 nm.

[0067] The emission spectrum of YVO4:Bi,Eu nanoparticles under 320 nm excitation is as follows: Figure 2 As shown, YVO4:Bi,Eu nanoparticles exhibit strong emission at 680 nm. The UV absorption spectrum of Ce6 is as follows. Figure 3As shown, it exhibits strong absorption at 665 nm. Therefore, the feasibility of the Ce6-mediated photodynamic bactericidal nanoparticle theory is demonstrated.

[0068] To determine the reactive oxygen species generated by Ce6-mediated photodynamic bactericidal nanoparticles under ultraviolet light irradiation, the following experiment was designed: 100 μL of the above-mentioned 0.5 mg / ml deionized solution of Ce6-mediated photodynamic bactericidal nanoparticles was taken, and 3 μL of ABDA reactive oxygen species probe was added. The solution was then irradiated with a 320 nm laser for 40 min, and the absorbance of the solution at 250 nm was measured every 5 min. Figure 4 The absorbance values ​​of the Ce6-mediated photodynamic bactericidal nanoparticle solution were measured under 320 nm UV light irradiation for 40 min. The data in the figure show that the absorbance of the Ce6-mediated photodynamic bactericidal nanoparticle aqueous solution decreased from 2.5 to 1.3 within 40 min, indicating a strong ability to generate reactive oxygen species under UV irradiation, which is beneficial for its bactericidal application.

[0069] The application of Ce6-mediated photodynamic bactericidal nanomaterials in inhibiting bacterial and fungal growth was measured by co-culturing nanoparticles with bacteria and fungi and irradiating them with ultraviolet light. The specific steps for inhibiting fungal growth are as follows: Take 10... 6 A CFU / mL *Botrytis cinerea* bacterial suspension was mixed with a certain amount of nanoparticles to achieve a final concentration of 0.1 mg / mL. The mixture was then irradiated under UV light for 5 min and incubated at 28°C for 4 h. The mixture was then evenly spread onto PDA medium and incubated at 28°C for 24 h. Several different treatments were analyzed and compared: co-culture with Ce6-mediated photodynamic bactericidal nanomaterials alone, UV irradiation alone, and both. The results are as follows: Figure 5 As shown. From Figure 5 The results lead us to the following conclusions: Compared to the blank control group, the treatment group simultaneously using Ce6-mediated photodynamic bactericidal nanomaterials and undergoing ultraviolet light irradiation showed the most significant antibacterial effect, reaching an inhibition rate of 99.72%. This finding has significant implications for practical applications. It is noteworthy that the antibacterial effect of the group co-cultured solely with the photodynamic bactericidal nanomaterials was lower than that of the group irradiated only with ultraviolet light. The specific steps for inhibiting bacteria are as follows: Collect samples at a concentration of 10... 6A CFU / mL suspension of Staphylococcus aureus was prepared, and nanoparticles were introduced to ensure a final concentration of 0.1 mg / mL. The resulting suspension was then irradiated with UV light for 5 min and incubated at 28°C for 4 h. The treated samples were then evenly spread on PDA medium and incubated at 28°C for another 24 h. Several different treatments were analyzed and compared, including: co-culture with Ce6-mediated photodynamic bactericidal nanomaterials only, UV irradiation alone, and a combination of both. The relevant experimental results are as follows: Figure 6 As shown. According to Figure 6 The data clearly show that, compared with the blank control group, the treatment group using Ce6-mediated photodynamic bactericidal nanomaterials and subjected to ultraviolet light irradiation exhibited the most significant antibacterial effect, with an inhibition rate of 99.56%. This result has important practical application value for the photodynamic therapy of Staphylococcus aureus. It is also noteworthy that the antibacterial effect of the group co-cultured with the photodynamic bactericidal nanomaterials alone was significantly lower than that of the group subjected to ultraviolet light irradiation alone.

[0070] The application of Ce6-mediated photodynamic sterilization film in fresh food preservation was demonstrated using strawberry and chicken models. The specific steps for strawberry preservation were as follows: Strawberries of uniform ripeness and size were selected, sterilized by immersion in alcohol for 5-30 seconds, placed in a beaker, and covered with the Ce6-mediated photodynamic sterilization film. The beakers were then placed in a cool, dry place. Ultraviolet light irradiation was applied for 20 minutes daily, with observations every other day. The final effect of the Ce6-mediated photodynamic sterilization film on strawberry preservation was as follows: Figure 7 As shown in the figure, the strawberries in the PE film group (control group) began to lose moisture on the third day; some mold appeared on the fifth day; and by the seventh day, the moisture loss of the strawberries increased, mold spots appeared, and a certain amount of tissue fluid seeped out, rendering them completely inedible. In contrast, the strawberries in the Ce6-mediated photodynamic sterilization film group (experimental group) showed almost no change on the third day. From the fifth day, small areas of wrinkling appeared; on the seventh day, the area of ​​wrinkling slightly expanded, but the impact on the edibility of the strawberries was minimal. The specific application steps for chicken preservation are as follows: Select healthy, fresh chicken breast, wash it thoroughly with distilled water, cut the chicken into 3cm×3cm×2cm pieces, cover the surface with the Ce6-mediated photodynamic sterilization film, and place it in a cool, dry place. Irradiate with ultraviolet light for 20 minutes daily, and observe every other day. Chicken covered with PE film was set as a blank control group. The final application effect of the Ce6-mediated photodynamic sterilization film in chicken preservation is shown in the figure. Figure 8As shown in the diagram. The experiment revealed that on the fourth day, the chicken in the control group became spoiled meat, with a dull, lackluster, and shrunken surface. On the sixth day, the chicken treated with the Ce6-mediated photodynamic sterilization film combined with ultraviolet light treatment also became spoiled meat, but with a brighter surface color. Analysis showed that while ultraviolet light alone delayed spoilage, the chicken surface of the group that received only ultraviolet light showed severe oxidation. The chicken treated with the Ce6-mediated photodynamic sterilization film combined with ultraviolet light treatment had a more vibrant surface color and a longer shelf life.

[0071] Example 2

[0072] The difference between this example and Example 1 is that the preparation process in this example is as follows:

[0073] Yttrium nitrate, europium nitrate, and bismuth nitrate were dissolved in deionized water at a ratio of 1:10:10, and then mixed with sodium vanadate solution (10 mg / mL) at a ratio of 1:10. The mixed solution was transferred to a 100 mL polytetrafluoroethylene reactor and placed in an oven at 230 °C for 2 h. After the reaction, the product obtained by centrifugation (12000 rpm / min, 4 min) was dissolved in deionized water and mixed with Ce6 solution (20 mol / L, 1 mL) to obtain a Ce6-mediated photodynamic bactericidal nanomaterial. The centrifuged product was then dissolved in CMC solution (0.5 mg / mL) at a mass ratio of 1:20, mixed for 12 h, poured onto a glass plate, and dried (30 °C, 48 h) to obtain the Ce6-mediated photodynamic bactericidal film.

[0074] Example 3

[0075] The difference between this example and Example 1 is that the preparation process in this example is as follows:

[0076] Yttrium nitrate, europium nitrate, and bismuth nitrate were dissolved in deionized water at a ratio of 1:0.01:0.01, and then mixed with sodium vanadate solution (0.1 mg / mL) at a ratio of 1:0.1. The mixed solution was transferred to a 100 mL polytetrafluoroethylene reactor and placed in an oven at 160 °C for 10 h. After the reaction, the product obtained by centrifugation (4000 rpm / min, 20 min) was dissolved in deionized water and mixed with Ce6 solution (2 mol / L, 20 mL) to obtain a Ce6-mediated photodynamic bactericidal nanomaterial. The centrifuged product was then dissolved in CMC solution (0.001 mg / mL) at a mass ratio of 1:5, mixed for 0.1 h, poured onto a glass plate, and dried (80 °C, 12 h) to obtain the Ce6-mediated photodynamic bactericidal film.

[0077] Example 4

[0078] The difference between this example and Example 1 is that the preparation process in this example is as follows:

[0079] Yttrium nitrate, europium nitrate, and bismuth nitrate were dissolved in deionized water at a ratio of 1:5:5, and then mixed with sodium vanadate solution (5 mg / mL) at a ratio of 1:5. The mixed solution was transferred to a 100 mL polytetrafluoroethylene reactor and placed in an oven at 200 °C for 6 h. After the reaction, the product obtained by centrifugation (8000 rpm / min, 15 min) was dissolved in deionized water and mixed with Ce6 solution (10 mol / L, 10 mL) to obtain a Ce6-mediated photodynamic bactericidal nanomaterial. The centrifuged product was then dissolved in CMC solution (0.3 mg / mL) at a mass ratio of 1:10, mixed for 6 h, poured onto a glass plate, and dried (30 °C, 36 h) to obtain the Ce6-mediated photodynamic bactericidal film.

[0080] Example 5

[0081] The difference between this example and Example 1 is that the preparation process in this example is as follows:

[0082] Yttrium nitrate, europium nitrate, and bismuth nitrate were dissolved in deionized water at a ratio of 1:1:1, and then mixed with sodium vanadate solution (1 mg / mL) at a ratio of 1:1. The mixed solution was transferred to a 100 mL polytetrafluoroethylene reactor and placed in an oven at 160 °C for 8 h. After the reaction, the product obtained by centrifugation (10000 rpm / min, 10 min) was dissolved in deionized water and mixed with Ce6 solution (1 mol / L, 10 mL) to obtain a Ce6-mediated photodynamic bactericidal nanomaterial. The centrifuged product was then dissolved in CMC solution (0.05 mg / mL) at a mass ratio of 1:1, mixed for 10 h, poured onto a glass plate, and dried (40 °C, 30 h) to obtain the Ce6-mediated photodynamic bactericidal film.

[0083] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, and is not intended to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention do not depart from the essence and scope of the technical solution of the present invention.

Claims

1. A method for preparing Ce6-mediated photodynamic bactericidal nanoparticles, characterized in that, The preparation method includes the following steps: S1. Yttrium nitrate, europium nitrate, and bismuth nitrate are dissolved in deionized water and then stirred and mixed with sodium vanadate solution; the mass ratio of yttrium nitrate, europium nitrate, and bismuth nitrate is 1:0.01-10:0.01-10; the concentration of sodium vanadate solution is 0.1-10 mg / mL; the volume ratio of deionized water to sodium vanadate solution is 0.1-10:

1. S2. The mixed solution is transferred to a polytetrafluoroethylene reactor for hydrothermal reaction to obtain YVO4:Bi,Eu nanoparticles. The YVO4:Bi,Eu nanoparticles produce 640 nm red light under 320 nm ultraviolet light irradiation, and the red light overlaps with the absorption spectrum of Ce6. The heating temperature of the hydrothermal reaction is 160-230℃, and the heating time is 2-10 h. S3. The product obtained after centrifugation is dissolved in deionized water and mixed with Ce6 solution to obtain a Ce6-mediated photodynamic bactericidal nanomaterial; in the photodynamic bactericidal nanomaterial, YVO4:Bi,Eu nanoparticles enhance the reactive oxygen yield of Ce6 through the above-mentioned red light, while blocking excessive ultraviolet light.

2. The method for preparing Ce6-mediated photodynamic bactericidal nanoparticles according to claim 1, characterized in that, The Ce6 solution concentration is 2–20 mol / L, and the Ce6 solution volume is 1–20 mL.

3. A method for preparing a Ce6-mediated photodynamic bactericidal film, characterized in that, The preparation method includes the following steps: S1. Dissolve Ce6-mediated photodynamic sterilization nanoparticles in a CMC solution, mix, pour onto a glass plate, and dry to obtain the Ce6-mediated photodynamic sterilization film; the Ce6-mediated photodynamic sterilization nanoparticles are prepared according to the preparation method described in claim 1, and the film can block excessive ultraviolet radiation from damaging food, and the generated active oxygen can also achieve a certain sterilization effect on fresh food.

4. The method for preparing a Ce6-mediated photodynamic bactericidal film according to claim 3, characterized in that, The mass ratio of the photodynamic bactericidal nanoparticles to the CMC solution is 1:5 to 20.

5. The method for preparing a Ce6-mediated photodynamic bactericidal film according to claim 3, characterized in that, The concentration of the CMC solution is 0.001–0.5 mg / mL.

6. The application of Ce6-mediated photodynamic bactericidal nanoparticles prepared by the method of any one of claims 1-2 in inhibiting bacteria and fungi.

7. The application of the Ce6-mediated photodynamic sterilization film prepared by the method of any one of claims 3-5 in the preservation of fresh food.

Images