An antibacterial silver nano colloid solution and its preparation method

Abstract

The present invention relates to the technical field of nano-silver antibacterial solutions, and specifically to an antibacterial nano-silver colloidal solution and a preparation method thereof, which include the following raw materials: silver nitrate 0.2 - 0.3%, glucose 0.1 - 0.2%, silver-loaded particles 1 - 3%, polyvinylpyrrolidone 2 - 3%, deionized water 30 - 40%, and the balance is glycerol; the preparation method is to dissolve silver nitrate in deionized water to obtain a solution; mix glucose, silver-loaded particles, polyvinylpyrrolidone and glycerol to obtain a mixed solution; combine the solution and the mixed solution and perform ultrasonic dispersion treatment to prepare the antibacterial nano-silver colloidal solution. The present invention adds silver-loaded particles, loads sufficient nano-silver inside the hollow SiO2, realizes the slow release of silver ions, prolongs the release time, improves the bacteriostatic time effect of the antibacterial nano-silver colloidal solution, and makes it have good antibacterial persistence.

Description

Technical Field

[0001] The present invention relates to the technical field of nano-silver antibacterial solutions, and particularly to an antibacterial nano-silver colloidal solution and a preparation method thereof. Background Art

[0002] Nano-silver has extremely strong nano-activity and exhibits extraordinary antibacterial ability. It can kill common pathogenic microorganisms such as bacteria, fungi, mycoplasmas, and chlamydiae at extremely low concentrations. Compared with antibiotics, nano-silver has the characteristics of its bactericidal effect not being affected by the pH value, broad-spectrum antibacterial, no drug resistance, long-lasting efficacy, stronger bactericidal power when encountering water, safety and environmental protection, etc. It is an ideal antibacterial material and can be widely used in many industries.

[0003] Due to the extremely large specific surface area of nano-silver particles, it is very easy for the particles to agglomerate with each other, forming larger-sized aggregates, resulting in the loss of the physical properties and functions that nano-particles should have during final application, thereby affecting the development and application of its products. In order to reduce the occurrence of nano-silver agglomeration, nano-silver is often loaded on various carriers such as zeolites, sepiolites, and oxides to form a relatively stable dispersion; however, when such carriers are directly impregnated in silver salt solutions, the exchange amount with silver ions is limited, making it difficult to load a sufficient amount of nano-silver, which affects the persistent antibacterial property of the nano-silver colloidal solution. Based on this, an antibacterial nano-silver colloidal solution and a preparation method thereof are proposed. Summary of the Invention

[0004] To overcome the deficiencies of the prior art, the present invention provides an antibacterial nano-silver colloidal solution and a preparation method thereof, which load nano-silver in sufficient quantity inside hollow SiO₂, realizing the slow release of silver ions, prolonging the release time, and endowing it with good antibacterial persistence.

[0005] To achieve the above object, the present invention provides the following technical solution: An antibacterial nano-silver colloidal solution, in terms of mass percentage, comprises the following raw materials: silver nitrate 0.2 - 0.3%, glucose 0.1 - 0.2%, silver-loaded particles 1 - 3%, polyvinylpyrrolidone 2 - 3%, deionized water 30 - 40%, and the balance is glycerol.

[0006] Preferably, the silver-loaded particles are prepared as follows: S1. Stir methyl methacrylate, divinylbenzene, toluene and azobisisobutyronitrile evenly, then add an aqueous solution of polyvinyl alcohol for mixing. After the reaction ends, add sufficient ethanol to dissolve toluene by shaking, and after filtration, rinsing and drying, obtain PMMA (polymethyl methacrylate) porous microspheres; S2. Add the PMMA porous microspheres to a sodium hydroxide solution. After the stirring reaction ends, filter, rinse and dry to obtain carboxylated PMMA porous microspheres; S3. Disperse the carboxylated PMMA porous microspheres in absolute ethanol, then add a silver nitrate solution to the dispersion of carboxylated PMMA porous microspheres, stir initially, and then add a polyvinylpyrrolidone alcohol solution and stir secondly to obtain a PMMA-Ag composite microsphere dispersion; S4. Add ammonia water and tetraethyl orthosilicate to the PMMA-Ag composite microsphere dispersion for stirring reaction. After the reaction ends, filter, rinse and dry to obtain PMMA-Ag-SiO2 composite microspheres; S5. Calcinate the PMMA-Ag-SiO2 composite microspheres at a high temperature to obtain the silver-loaded particles.

[0007] Preferably, in step S1, the volume ratio of methyl methacrylate, divinylbenzene, toluene and the aqueous solution of polyvinyl alcohol is 20:1:2:180; the material-liquid ratio of azobisisobutyronitrile and divinylbenzene is 1:2.5 g / ml; the mass concentration of the aqueous solution of polyvinyl alcohol is 5%.

[0008] Preferably, in step S2, the concentration of the sodium hydroxide solution is 0.2 - 0.4 mol / L; the temperature of the stirring reaction is 75 - 85 °C, and the time of the stirring reaction is 2 - 4 h.

[0009] Preferably, in step S3, the material-liquid ratio of the carboxylated PMMA porous microspheres and absolute ethanol is 5 mg / ml; the volume ratio of the dispersion of carboxylated PMMA porous microspheres, the silver nitrate solution and the polyvinylpyrrolidone alcohol solution is 5:5:2; the concentration of the silver nitrate solution is 0.05 mol / L.

[0010] Preferably, in step S3, the polyvinylpyrrolidone alcohol solution is prepared by dissolving polyvinylpyrrolidone in absolute ethanol at a material-liquid ratio of 1:15 g / ml.

[0011] Preferably, in step S3, the time of the initial stirring is 40 - 50 min, and the time of the second stirring is 70 - 90 min.

[0012] Preferably, in step S4, the volume ratio of the PMMA-Ag composite microsphere dispersion, ammonia water and tetraethyl orthosilicate is 50:3:1; the time of the stirring reaction is 120 - 150 min.

[0013] Preferably, in step S5, the temperature of the high-temperature calcination is 500 - 550 °C, and the time of the high-temperature calcination is 100 - 150 min.

[0014] The present invention also provides a preparation method of an antibacterial nano silver colloidal solution, which specifically includes the following steps:

[0015] (1) Dissolve silver nitrate in deionized water to obtain a dissolution solution;

[0016] (2) Mix glucose, silver-loaded particles, polyvinylpyrrolidone, and glycerol to obtain a mixed solution;

[0017] (3) Combine the dissolution solution and the mixed solution, and perform ultrasonic dispersion treatment to prepare an antibacterial nano silver colloidal solution.

[0018] The present invention provides an antibacterial nano silver colloidal solution and a preparation method thereof, which have the following beneficial effects compared with the prior art:

[0019] The present invention adds silver-loaded particles, loads nano silver in sufficient quantity inside the hollow SiO2, realizes the slow release of silver ions, extends the release time, improves the antibacterial time limit of the antibacterial nano silver colloidal solution, and makes it have good antibacterial persistence.

[0020] The present invention uses toluene as a pore-forming agent to form more pores inside the PMMA microspheres, providing more loading space for nano silver to achieve sufficient loading of nano silver; at the same time, carboxylating the PMMA microspheres to make them carry negative charges, which can better combine with Ag + to further promote the combined loading of nano silver; in addition, then using ammonia water and tetraethyl orthosilicate to form SiO2 on the surface of the microspheres, and removing the PMMA microspheres by high-temperature calcination to make the SiO2 generate mesopores, and nano silver can be sufficiently loaded in the mesopores of SiO2, thus realizing the slow release of Ag + of.

[0021] By using silver nitrate, silver-loaded particles, and glucose in the present invention, in the early stage, the bare nano silver generated by silver nitrate can be directly released for antibacterial purposes to prevent the antibacterial effect in the early stage from being affected by the slow release of silver-loaded particles. In the middle and late stages, the slow release of silver-loaded particles can achieve the purpose of persistent antibacterial; the addition of glucose, in synergy with polyvinylpyrrolidone, ensures the stability of the bare nano silver. Description of the Drawings

[0022] The drawings described herein are used to provide a further understanding of the present application, and constitute a part of the present application. The schematic embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation to the present application. In the drawings:

[0023] Figure 1This is the infrared spectrogram of PMMA porous microspheres and carboxylated PMMA porous microspheres in Example 3 of the present invention;

[0024] Figure 2 This is the graph of the change in silver ion concentration released by silver-loaded microparticles with the soaking time in the present invention. Detailed implementation manners

[0025] The following examples are used to elaborate in detail the implementation manners of the present application, so as to fully understand the implementation process of how the present application uses technical means to solve technical problems and achieve technical effects and implement accordingly.

[0026] Example 1

[0027] The preparation of silver-loaded microparticles is as follows:

[0028] S1. Stir methyl methacrylate, divinylbenzene, toluene and azobisisobutyronitrile evenly, then add an aqueous solution of polyvinyl alcohol with a mass concentration of 5% for mixing. After the reaction ends, add a sufficient amount of ethanol to dissolve toluene by shaking, and after filtration, washing and drying, PMMA porous microspheres are obtained;

[0029] Among them, the volume ratio of methyl methacrylate, divinylbenzene, toluene and the aqueous solution of polyvinyl alcohol is 20:1:2:180; the material-liquid ratio of azobisisobutyronitrile and divinylbenzene is 1:2.5 g / ml.

[0030] S2. Add the PMMA porous microspheres to a 0.2 mol / L sodium hydroxide solution, stir and react at 85 °C for 2 h, and after filtration, washing and drying, carboxylated PMMA porous microspheres are obtained.

[0031] S3. Disperse the carboxylated PMMA porous microspheres in absolute ethanol according to a material-liquid ratio of 5 mg / ml, then add a 0.05 mol / L silver nitrate solution to the obtained carboxylated PMMA porous microsphere dispersion, stir for 50 min for the first time, and then add a polyvinylpyrrolidone alcohol solution and stir for 70 min for the second time to obtain a PMMA-Ag composite microsphere dispersion;

[0032] Among them, the volume ratio of the carboxylated PMMA porous microsphere dispersion, the silver nitrate solution and the polyvinylpyrrolidone alcohol solution is 5:5:2. The polyvinylpyrrolidone alcohol solution is prepared by dissolving polyvinylpyrrolidone in absolute ethanol according to a material-liquid ratio of 1:15 g / ml.

[0033] S4. Add ammonia water and tetraethyl orthosilicate to the PMMA-Ag composite microsphere dispersion. The volume ratio of the PMMA-Ag composite microsphere dispersion, ammonia water and tetraethyl orthosilicate is 50:3:1, stir and react for 120 min, and after filtration, washing and drying, PMMA-Ag-SiO2 composite microspheres are obtained.

[0034] S5. Calcinate the PMMA-Ag-SiO₂ composite microspheres at 550 °C for 100 min to obtain silver-loaded particles.

[0035] Example 2

[0036] The preparation of silver-loaded particles is as follows:

[0037] S1. Stir methyl methacrylate, divinylbenzene, toluene and azobisisobutyronitrile evenly, then add an aqueous solution of polyvinyl alcohol with a mass concentration of 5% for mixing. After the reaction ends, add sufficient ethanol to dissolve toluene by shaking. After filtration, rinsing and drying, PMMA porous microspheres are obtained.

[0038] Among them, the volume ratio of methyl methacrylate, divinylbenzene, toluene and the aqueous solution of polyvinyl alcohol is 20:1:2:180; the material ratio of azobisisobutyronitrile and divinylbenzene is 1:2.5 g / ml.

[0039] S2. Add the PMMA porous microspheres to a 0.4 mol / L sodium hydroxide solution, stir and react at 75 °C for 4 h. After filtration, rinsing and drying, carboxylated PMMA porous microspheres are obtained.

[0040] S3. Disperse the carboxylated PMMA porous microspheres in absolute ethanol according to the material ratio of 5 mg / ml. Then add a 0.05 mol / L silver nitrate solution to the obtained dispersion of carboxylated PMMA porous microspheres. Stir for 40 min for the first time, then add a polyvinylpyrrolidone alcohol solution and stir for 90 min for the second time to obtain a dispersion of PMMA-Ag composite microspheres.

[0041] Among them, the volume ratio of the dispersion of carboxylated PMMA porous microspheres, silver nitrate solution and polyvinylpyrrolidone alcohol solution is 5:5:2. The polyvinylpyrrolidone alcohol solution is prepared by dissolving polyvinylpyrrolidone in absolute ethanol according to the material ratio of 1:15 g / ml.

[0042] S4. Add ammonia water and tetraethyl orthosilicate to the dispersion of PMMA-Ag composite microspheres. The volume ratio of the dispersion of PMMA-Ag composite microspheres, ammonia water and tetraethyl orthosilicate is 50:3:1. Stir and react for 150 min. After filtration, rinsing and drying, PMMA-Ag-SiO₂ composite microspheres are obtained.

[0043] S5. Calcinate the PMMA-Ag-SiO₂ composite microspheres at 500 °C for 150 min to obtain silver-loaded particles.

[0044] Example 3

[0045] The preparation of silver-loaded particles is as follows:

[0046] S1. Stir methyl methacrylate, divinylbenzene, toluene and azobisisobutyronitrile evenly, then add an aqueous solution of polyvinyl alcohol with a mass concentration of 5% for mixing. After the reaction ends, add sufficient ethanol to dissolve toluene by shaking, and obtain PMMA porous microspheres through suction filtration, rinsing and drying.

[0047] Among them, the volume ratio of methyl methacrylate, divinylbenzene, toluene and the aqueous solution of polyvinyl alcohol is 20:1:2:180; the material ratio of azobisisobutyronitrile and divinylbenzene is 1:2.5 g / ml.

[0048] S2. Add the PMMA porous microspheres to a 0.3 mol / L sodium hydroxide solution, stir and react at 80 °C for 3 h, and obtain carboxylated PMMA porous microspheres through filtration, rinsing and drying.

[0049] S3. Disperse the carboxylated PMMA porous microspheres in absolute ethanol according to a material ratio of 5 mg / ml, then add a 0.05 mol / L silver nitrate solution to the obtained dispersion of carboxylated PMMA porous microspheres, stir for 45 min for the first time, and then add a polyvinylpyrrolidone alcohol solution and stir for 80 min for the second time to obtain a dispersion of PMMA-Ag composite microspheres.

[0050] Among them, the volume ratio of the dispersion of carboxylated PMMA porous microspheres, silver nitrate solution and polyvinylpyrrolidone alcohol solution is 5:5:2. The polyvinylpyrrolidone alcohol solution is prepared by dissolving polyvinylpyrrolidone in absolute ethanol according to a material ratio of 1:15 g / ml.

[0051] S4. Add ammonia water and tetraethyl orthosilicate to the dispersion of PMMA-Ag composite microspheres. The volume ratio of the dispersion of PMMA-Ag composite microspheres, ammonia water and tetraethyl orthosilicate is 50:3:1, stir and react for 130 min, and obtain PMMA-Ag-SiO2 composite microspheres through suction filtration, rinsing and drying.

[0052] S5. Calcinate the PMMA-Ag-SiO2 composite microspheres at 535 °C for 125 min to obtain silver-loaded microparticles.

[0053] The infrared spectra of the obtained PMMA porous microspheres and carboxylated PMMA porous microspheres in this example are as Figure 1 shown. It can be seen from the spectrum of the PMMA porous microspheres that two characteristic absorption peaks appear near 1725 cm -1 and 1630 cm -1 , which are attributed to the C=O stretching vibrations of the ester group and carboxyl group in the PMMA molecule. Compared with the infrared spectrum of the PMMA porous microspheres, the carboxylated PMMA porous microspheres have a peak at 1630 cm -1A stronger absorption peak appeared at [specific location], which is attributed to the stretching vibration of C=O of the carboxyl groups generated after the alkali treatment of PMMA porous microspheres. The results show that some ester groups of PMMA porous microspheres have been converted into carboxyl groups, confirming the formation of carboxylated PMMA porous microspheres.

[0054] Example 4

[0055] An antibacterial nano-silver colloidal solution, by mass percentage, includes the following raw materials: 0.3% silver nitrate, 0.1% glucose, 3% silver-loaded particles in Example 1, 2% polyvinylpyrrolidone, 40% deionized water, and the balance is glycerol.

[0056] The preparation method of the above antibacterial nano-silver colloidal solution includes the following steps:

[0057] (1) Dissolve silver nitrate in deionized water to obtain a solution;

[0058] (2) Mix glucose, the silver-loaded particles in Example 1, polyvinylpyrrolidone and glycerol to obtain a mixture;

[0059] (3) Combine the solution and the mixture, and perform ultrasonic dispersion treatment to obtain the antibacterial nano-silver colloidal solution.

[0060] Example 5

[0061] An antibacterial nano-silver colloidal solution, by mass percentage, includes the following raw materials: 0.2% silver nitrate, 0.2% glucose, 1% silver-loaded particles in Example 2, 3% polyvinylpyrrolidone, 30% deionized water, and the balance is glycerol.

[0062] The preparation method of the above antibacterial nano-silver colloidal solution includes the following steps:

[0063] (1) Dissolve silver nitrate in deionized water to obtain a solution;

[0064] (2) Mix glucose, the silver-loaded particles in Example 2, polyvinylpyrrolidone and glycerol to obtain a mixture;

[0065] (3) Combine the solution and the mixture, and perform ultrasonic dispersion treatment to obtain the antibacterial nano-silver colloidal solution.

[0066] Example 6

[0067] An antibacterial nano-silver colloidal solution, by mass percentage, includes the following raw materials: 0.25% silver nitrate, 0.15% glucose, 2.2% silver-loaded particles in Example 3, 2.5% polyvinylpyrrolidone, 35% deionized water, and the balance is glycerol.

[0068] The preparation method of the above-mentioned antibacterial silver nano-colloid solution comprises the following steps:

[0069] (1) Dissolve silver nitrate in deionized water to obtain a solution;

[0070] (2) Mix glucose, the silver-loaded particles in Example 3, polyvinylpyrrolidone and glycerol to obtain a mixed solution;

[0071] (3) Combine the solution and the mixed solution, and perform ultrasonic dispersion treatment to prepare the antibacterial silver nano-colloid solution.

[0072] Comparative Example 1

[0073] An antibacterial silver nano-colloid solution and its preparation method are basically the same as those in Example 6, except that the preparation of the silver-loaded particles is as follows:

[0074] S1. Stir methyl methacrylate, divinylbenzene and azobisisobutyronitrile evenly, then add an aqueous solution of polyvinyl alcohol with a mass concentration of 5% for mixing. After the reaction ends, perform suction filtration, rinsing and drying to obtain PMMA microspheres;

[0075] Among them, the volume ratio of methyl methacrylate, divinylbenzene and the aqueous solution of polyvinyl alcohol is 20:1:180; the material ratio of azobisisobutyronitrile and divinylbenzene is 1:2.5 g / ml.

[0076] Steps S2 - S5, refer to the corresponding content in Example 3, and finally prepare the silver-loaded particles.

[0077] Comparative Example 2

[0078] An antibacterial silver nano-colloid solution and its preparation method are basically the same as those in Example 6, except that the preparation of the silver-loaded particles is as follows:

[0079] S1. Stir methyl methacrylate, divinylbenzene, toluene and azobisisobutyronitrile evenly, then add an aqueous solution of polyvinyl alcohol with a mass concentration of 5% for mixing. After the reaction ends, add sufficient ethanol to dissolve toluene by shaking, perform suction filtration, rinsing and drying to obtain PMMA porous microspheres;

[0080] Among them, the volume ratio of methyl methacrylate, divinylbenzene, toluene and the aqueous solution of polyvinyl alcohol is 20:1:2:180; the material ratio of azobisisobutyronitrile and divinylbenzene is 1:2.5 g / ml.

[0081] S2. Disperse PMMA porous microspheres in absolute ethanol at a material-liquid ratio of 5 mg / ml. Subsequently, add 0.05 mol / L silver nitrate solution to the obtained PMMA porous microsphere dispersion, stir for 45 min for the first time, then add polyvinylpyrrolidone alcohol solution, and stir for 80 min for the second time to obtain a PMMA-Ag composite microsphere dispersion;

[0082] Among them, the volume ratio of the PMMA porous microsphere dispersion, silver nitrate solution and polyvinylpyrrolidone alcohol solution is 5:5:2. The polyvinylpyrrolidone alcohol solution is prepared by dissolving polyvinylpyrrolidone in absolute ethanol at a material-liquid ratio of 1:15 g / ml.

[0083] S3. Add ammonia water and tetraethyl orthosilicate to the PMMA-Ag composite microsphere dispersion. The volume ratio of the PMMA-Ag composite microsphere dispersion, ammonia water and tetraethyl orthosilicate is 50:3:1. Stir and react for 130 min, and obtain PMMA-Ag-SiO2 composite microspheres through suction filtration, rinsing and drying.

[0084] S4. Calcinate the PMMA-Ag-SiO2 composite microspheres at 535 °C for 125 min to obtain silver-loaded particles.

[0085] Comparative Example 3

[0086] An antibacterial nano-silver colloidal solution, by mass percentage, comprises the following raw materials: 0.35% of silver nitrate, 0.15% of glucose, 2.5% of polyvinylpyrrolidone, 35% of deionized water, and the balance is glycerol. The influence of the lack of silver content in the silver-loaded particles is compensated by increasing the content of silver nitrate.

[0087] The preparation method of the above antibacterial nano-silver colloidal solution comprises the following steps:

[0088] (1) Dissolve silver nitrate in deionized water to obtain a solution;

[0089] (2) Mix glucose, polyvinylpyrrolidone and glycerol to obtain a mixture;

[0090] (3) Combine the solution and the mixture, and perform ultrasonic dispersion treatment to obtain an antibacterial nano-silver colloidal solution.

[0091] Comparative Example 4

[0092] An antibacterial nano-silver colloidal solution, by mass percentage, comprises the following raw materials: 0.25% of silver nitrate, 2.2% of the silver-loaded particles in Example 3, 2.5% of polyvinylpyrrolidone, 35% of deionized water, and the balance is glycerol.

[0093] The preparation method of the above antibacterial nano-silver colloidal solution comprises the following steps:

[0094] (1) Dissolve silver nitrate in deionized water to obtain a solution.

[0095] (2) Mix the silver-loaded particles, polyvinylpyrrolidone, and glycerol in Example 3 to obtain a mixture.

[0096] (3) Combine the solution and the mixture, and perform ultrasonic dispersion treatment to prepare an antibacterial silver nanocolloid solution.

[0097] Quality inspection

[0098] 1. Use the antibacterial silver nanocolloid solutions in Examples 4 - 6 and Comparative Examples 1 - 4 as samples for testing. The specific test results are shown in Table 1.

[0099] Immerse the pure cotton cloth in the corresponding sample, and then take it out and dry it naturally. Conduct antibacterial performance testing according to the standard of FZ / T 73024 - 2014, and record it as the initial antibacterial rate.

[0100] Immerse the pure cotton cloth in the corresponding sample, then take it out and dry it naturally, and then soak it in deionized water. Select the time points of 1 month and 6 months, take out the samples and dry them, and conduct antibacterial performance testing according to the standard of FZ / T 73024 - 2014, and record it as the persistent antibacterial rate.

[0101] Table 1 Antibacterial property

[0102]

[0103] As can be seen from the above table:

[0104] (1) The persistent antibacterial rates of the samples in Comparative Example 1 and Comparative Example 2 are not as good as that in Example 6, indicating that the porous channel treatment and carboxylation treatment of PMMA microspheres increase the loading amount of silver nanoparticles and have better slow-release performance.

[0105] (2) The initial antibacterial rate of the sample in Comparative Example 3 shows good performance, but the persistent antibacterial effect is far less than that in Example 6, indicating that the silver-loaded particles can indeed achieve the slow release of silver ions, prevent the large loss of silver ions, and improve the persistence of antibacterial.

[0106] (3) The sample in Comparative Example 4 is not much different from that in Example 6, and the persistent antibacterial rate is significantly lower than that in Example 6 at the 1-month time point, indicating that the addition of glucose has a certain improvement effect on the antibacterial performance of the antibacterial silver nanocolloid solution.

[0107] 2. Using the silver-loaded particles in Example 3, Comparative Example 1, and Comparative Example 2 as objects, their silver ion sustained-release performance was detected. 0.2 g of silver-loaded particles were dispersed in 20 ml of deionized water and placed on a micro oscillator to oscillate at a speed of 60 rpm to accelerate the release of silver ions. Multiple time points were selected, and the oscillating liquid was centrifuged to separate the supernatant, and an inductively coupled plasma mass spectrometer was used to measure the silver ion concentration in the supernatant to judge its sustained-release performance. The specific detection results are as Figure 2 shown.

[0108] It can be seen from Figure 2 that: the maximum silver ion concentration in Example 3 is significantly higher than that in Comparative Example 1 and Comparative Example 2, indicating that the porous channel treatment and carboxylation treatment of PMMA microspheres can indeed allow more silver nanoparticles to be loaded in the microspheres; the silver-loaded particles in Comparative Example 1, Comparative Example 2, and Example 3 can continuously release silver ions and have a good sustained-release effect.

[0109] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An antibacterial nano-silver colloidal solution, characterized in that, By mass percentage, it includes the following raw materials: silver nitrate 0.2 - 0.3%, glucose 0.1 - 0.2%, silver-loaded particles 1 - 3%, polyvinylpyrrolidone 2 - 3%, deionized water 30 - 40%, and the balance is glycerol; The preparation of the silver-loaded particles is as follows: S1. Stir methyl methacrylate, divinylbenzene, toluene, and azobisisobutyronitrile evenly, then add an aqueous solution of polyvinyl alcohol for mixing. After the reaction ends, add sufficient ethanol to dissolve toluene by shaking, and after filtration, washing, and drying, PMMA porous microspheres are obtained; S2. Add the PMMA porous microspheres to a sodium hydroxide solution. After the stirring reaction ends, after filtration, washing, and drying, carboxylated PMMA porous microspheres are obtained; S3. Disperse the carboxylated PMMA porous microspheres in absolute ethanol, then add a silver nitrate solution to the carboxylated PMMA porous microsphere dispersion, stir initially, and then add a polyvinylpyrrolidone alcohol solution and stir secondly to obtain a PMMA-Ag composite microsphere dispersion; S4. Add ammonia water and tetraethyl orthosilicate to the PMMA-Ag composite microsphere dispersion for stirring reaction. After the reaction ends, after filtration, washing, and drying, PMMA-Ag-SiO₂ composite microspheres are obtained; S5. Conduct high-temperature calcination on the PMMA-Ag-SiO₂ composite microspheres to obtain the silver-loaded particles.

2. The antibacterial nano silver colloid solution according to claim 1, characterized in that, In step S1, the volume ratio of methyl methacrylate, divinylbenzene, toluene, and the aqueous solution of polyvinyl alcohol is 20:1:2:180; the material ratio of azobisisobutyronitrile and divinylbenzene is 1:2.5 g / ml; the mass concentration of the aqueous solution of polyvinyl alcohol is 5%.

3. The antibacterial nano-silver colloid solution according to claim 1, wherein In step S2, the concentration of the sodium hydroxide solution is 0.2 - 0.4 mol / L; the temperature of the stirring reaction is 75 - 85 °C, and the time of the stirring reaction is 2 - 4 h.

4. The antibacterial nano-silver colloid solution according to claim 1, characterized in that, In step S3, the material ratio of the carboxylated PMMA porous microspheres and absolute ethanol is 5 mg / ml; the volume ratio of the carboxylated PMMA porous microsphere dispersion, the silver nitrate solution, and the polyvinylpyrrolidone alcohol solution is 5:5:2; the concentration of the silver nitrate solution is 0.05 mol / L.

5. The antibacterial nano-silver colloidal solution according to claim 1, characterized in that, In step S3, the polyvinylpyrrolidone alcohol solution is prepared by dissolving polyvinylpyrrolidone in absolute ethanol at a material ratio of 1:15 g / ml.

6. The antibacterial silver nano-colloid solution according to claim 1, wherein In step S3, the time of the initial stirring is 40 - 50 min, and the time of the second stirring is 70 - 90 min.

7. The antibacterial nano-silver colloid solution according to claim 1, characterized in that, In step S4, the volume ratio of the PMMA-Ag composite microsphere dispersion, ammonia water, and tetraethyl orthosilicate is 50:3:1; the time of the stirring reaction is 120 - 150 min.

8. The antibacterial silver nano-colloid solution according to claim 1, characterized in that, In step S5, the temperature of the high-temperature calcination is 500 - 550 °C, and the time of the high-temperature calcination is 100 - 150 min.

9. The preparation method of the antibacterial nano-silver colloid solution according to any one of claims 1-8, characterized in that, It includes the following steps: (1) Dissolve silver nitrate in deionized water to obtain a dissolution solution; (2) Mix glucose, silver-loaded particles, polyvinylpyrrolidone, and glycerol to obtain a mixed solution; (3) Combine the dissolution solution and the mixed solution and conduct ultrasonic dispersion treatment to obtain an antibacterial nano-silver colloid solution.

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