Preparation method of blue light responsive fluorine-nitrogen co-doped zinc oxide antibacterial agent

Abstract

The invention discloses a preparation method of a blue light responsive fluorine-nitrogen co-doped zinc oxide antibacterial agent, relates to the technical field of dental caries repair materials, and solves the problem of secondary caries caused by the lack of antibacterial effect of dental clinical repair materials. The method comprises the following steps: adding a hexahydrate zinc nitrate solution containing ammonium fluoride and urea to a concentrated sodium hydroxide solution, and stirring to obtain a precursor solution; washing the precursor solution with deionized water and anhydrous ethanol, filtering, drying in an oven, and annealing to obtain fluorine-nitrogen co-doped zinc oxide; the fluorine-nitrogen co-doped zinc oxide prepared by the invention has a good antibacterial effect on major oral bacteria Streptococcus mutans, and exhibits good biocompatibility, and the antibacterial effect is improved under the illumination of a dental curing lamp, thereby solving the technical problem that the existing dental composite resin cannot achieve long-term antibacterial effect.

Description

Technical Field

[0001] The invention relates to the technical field of antibacterial materials for dental caries repair, in particular to a method for preparing a blue light responsive fluorine and nitrogen co-doped zinc oxide antibacterial agent. Background Art

[0002] Dental caries is a chronic disease that has long threatened human oral health. According to modern dental caries etiology theory, oral flora imbalance may lead to acid accumulation in the oral cavity, causing tooth demineralization and thus inducing the formation of dental caries. Bacteria in human dental plaque can produce acid, which can cause slow local chemical dissolution of tooth hard tissue.

[0003] The Chinese invention patent with application number CN201910044740.8 discloses a high-strength dental composite resin and a preparation method thereof. The raw materials include inorganic fillers, organic monomers and photoinitiators, and the inorganic fillers are co-fillers composed of spherical mesoporous fillers and spherical fillers. The preparation method includes: premixing the spherical mesoporous filler, organic monomer and photoinitiator, further mixing them in a three-roll grinder, adding the spherical filler, and subjecting them to vacuum negative pressure treatment to obtain an uncured composite resin paste; finally, curing them with visible light to obtain a dental composite resin. The dental composite resin preparation method of the invention is simple, has excellent mechanical properties, and has good application prospects.

[0004] The above patent has certain defects and does not have antibacterial effect, which may cause secondary caries and other problems. At present, traditional antibacterial agents such as chlorhexidine (CHX) and antibiotics used for caries treatment have good antibacterial effect on planktonic bacteria, but they have poor antibacterial effect on bacteria in cell membranes, because bacteria have extracellular matrix rich in exopolysaccharides (EPS), which makes bacterial cell membrane shield against drugs and make them resistant. Summary of the invention

[0005] The purpose of the present invention is to provide a method for preparing a blue light responsive fluorine-nitrogen co-doped zinc oxide antibacterial agent, so as to solve the technical problem that the existing composite resin cannot achieve long-term antibacterial effect.

[0006] To achieve the above object, the technical solution adopted by the present invention is: a method for preparing a blue light responsive fluorine-nitrogen co-doped zinc oxide antibacterial agent, comprising the following steps:

[0007] Step 1, adding a zinc nitrate hexahydrate solution containing ammonium fluoride and urea into a concentrated sodium hydroxide solution, and stirring to obtain a precursor solution;

[0008] Step 1 is as follows:

[0009] At 20-25° C., a zinc nitrate hexahydrate solution containing ammonium fluoride and urea is added to a continuously stirred sodium hydroxide solution, and then the reaction is continued at 75-80° C. at a stirring speed of 500-600 rpm for 2-2.5 hours to obtain a precursor solution;

[0010] Step 2, washing the precursor solution with deionized water and anhydrous ethanol, filtering, and drying in an oven to obtain fluorine-nitrogen co-doped zinc oxide;

[0011] Step 2 is as follows:

[0012] The precursor solution obtained by the reaction was washed three times with deionized water using a vacuum filter, and then mixed with the precipitate using ethanol and stirred evenly. After filtering and washing three times, it was placed in an oven at 60-70° C. and dried for 12-15 h to obtain fluorine-nitrogen co-doped zinc oxide.

[0013] As a further improvement of the present invention, in step 1, the zinc nitrate solution is added dropwise to the continuously stirred sodium hydroxide solution at a speed of 15-20 mL / s.

[0014] As a further improvement of the present invention, the molar ratios of the zinc nitrate hexahydrate solution to the sodium hydroxide, ammonium fluoride and urea are 1:8-1:11, 1:1-1:1.2 and 1:1-1:3 respectively.

[0015] The beneficial effects of the present invention are:

[0016] 1. The fluorine-nitrogen co-doped zinc oxide prepared by the present invention has a simple preparation method and mild reaction conditions and can be applied to the field of dental restoration filling resins.

[0017] 2. The fluorine-nitrogen co-doped zinc oxide of the present invention releases zinc ions (Zn 2+ The main reason for the antibacterial effect of fluorine-nitrogen co-doped zinc oxide is that under the irradiation of clinical light curing lamps, the electrons in the valence band of zinc oxide will be excited to jump to the conduction band, generating e - / h + Yes, h + It can oxidize H2O into ·OH, which can act as a strong oxidant to inactivate bacteria. Under lightless conditions, Zn 2+ It destroys the bacterial cell membrane, causing the leakage of the cytoplasmic matrix, thereby inactivating the bacteria and completing the sterilization process. Zinc oxide can also produce reactive oxygen species, destroying the bacterial DNA, protein and cell membrane, causing bacterial death.

[0018] 3. In the present invention, zinc oxide has good biocompatibility, safety and stability. The U.S. Food and Drug Administration considers it to be one of the safe zinc compounds and has low cost.

[0019] 4. The fluorine-nitrogen co-doped zinc oxide of the present invention can effectively inhibit the growth of Streptococcus mutans, and the antibacterial property can reach 99.99%. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is the X-ray diffraction spectrum of fluorine-nitrogen co-doped zinc oxide in an embodiment of the present invention;

[0021] Figure 2 This is a scanning electron microscope image of fluorine-nitrogen co-doped zinc oxide in an embodiment of the present invention;

[0022] Figure 3 This is a cytotoxicity test diagram of fluorine-nitrogen co-doped zinc oxide in an embodiment of the present invention;

[0023] Figure 4 This is the contact antibacterial rate graph of the control group (silicon dioxide) against Streptococcus mutans;

[0024] Figure 5 This is a graph showing the antibacterial effect of fluorine-nitrogen co-doped zinc oxide on Streptococcus mutans under no light / blue light using a gradient dilution method in Example 1 of the present invention;

[0025] Figure 6 This is a graph showing the antibacterial effect of fluorine-nitrogen co-doped zinc oxide on Streptococcus mutans under no light / blue light using a gradient dilution method in Example 2 of the present invention;

[0026] Figure 7 This is a graph showing the antibacterial effect of fluorine-nitrogen co-doped zinc oxide on Streptococcus mutans under no light / blue light using a gradient dilution method in Example 3 of the present invention;

[0027] Figure 8 This is a graph showing the antibacterial effect of fluorine-nitrogen co-doped zinc oxide on Streptococcus mutans under no light / blue light using a gradient dilution method in Example 4 of the present invention;

[0028] Fig. 9 This is a graph showing the antibacterial results of fluorine-nitrogen co-doped zinc oxide using a gradient dilution method to detect F,N-ZnO against Streptococcus mutans under no light / blue light in Example 5 of the present invention. DETAILED DESCRIPTION

[0029] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0030] Example 1

[0031] A method for preparing a blue light responsive fluorine-nitrogen co-doped zinc oxide antibacterial agent comprises the following steps:

[0032] Weigh 3.0 g NaOH with an analytical balance and dissolve it in 150 mL deionized water, then weigh 0.22 g NH4F, 0.9CH4N2O, and 2.23 g Zn(NO3)2 6H2O and dissolve them in 150 mL deionized water. After stirring at 25 °C for 30 min, add the zinc nitrate solution containing ammonium fluoride and urea to the continuously stirred concentrated sodium hydroxide solution at a rate of 15 mL / s, and use a magnetic stirrer to react the solution at 80 °C for 2 h, with a magnetic stirring speed of 500 rpm. The initial product obtained by the reaction was filtered using a vacuum filter, washed three times with deionized water and anhydrous ethanol, and then placed in an oven at 60 °C for 12 h, and then placed in a muffle furnace at 600 °C for 2 h to obtain fluorine-nitrogen co-doped zinc oxide.

[0033] Example 2

[0034] A method for preparing a blue light responsive fluorine-nitrogen co-doped zinc oxide antibacterial agent comprises the following steps:

[0035] Weigh 2.4 g NaOH with an analytical balance and dissolve it in 150 mL deionized water, then weigh 0.28 g NH4F, 0.3CH4N2O, and 2.23 g Zn(NO3)2 6H2O and dissolve them in 150 mL deionized water. After stirring at 20 °C for 30 min, add the zinc nitrate solution containing ammonium fluoride and urea to the continuously stirred concentrated sodium hydroxide solution at a rate of 15 mL / s, and use a magnetic stirrer to react the solution at 75 °C for 2 h, with a magnetic stirring speed of 500 rpm. The initial product obtained by the reaction was filtered using a vacuum filter, washed three times with deionized water and anhydrous ethanol, and then placed in an oven at 60 °C for 12 h, and then placed in a muffle furnace at 500 °C for 2 h to obtain fluorine-nitrogen co-doped zinc oxide.

[0036] Example 3

[0037] A method for preparing a blue light responsive fluorine-nitrogen co-doped zinc oxide antibacterial agent comprises the following steps:

[0038] Weigh 3.3 g NaOH with an analytical balance and dissolve it in 150 mL deionized water, then weigh 0.33 g NH4F, 0.9 g CH4N2O, and 2.23 g Zn(NO3)2 6H2O and dissolve them in 150 mL deionized water. After stirring at 20 °C for 30 min, add the zinc nitrate solution containing ammonium fluoride and urea to the continuously stirred concentrated sodium hydroxide solution at a rate of 20 mL / s, and use a magnetic stirrer to react the solution at 80 °C for 2.5 h, with a magnetic stirring speed of 600 rpm. The initial product obtained by the reaction was filtered using a vacuum filter, washed three times with deionized water and anhydrous ethanol, and then placed in an oven at 60 °C for 12 h, and then placed in a muffle furnace at 500 °C for 2 h to obtain fluorine-nitrogen co-doped zinc oxide.

[0039] Example 4

[0040] Weigh 1.0 g NaOH with an analytical balance and dissolve it in 150 mL deionized water, then weigh 0.66 g NH4F, 0.36CH4N2O, and 2.23 g Zn(NO3)2 6H2O and dissolve them in 150 mL deionized water. After stirring at 25 °C for 30 min, add the zinc nitrate solution containing ammonium fluoride and urea to the continuously stirred concentrated sodium hydroxide solution at a rate of 30 mL / s, and use a magnetic stirrer to react the solution at 100 °C for 2 h, with a magnetic stirring speed of 1000 rpm. The initial product obtained by the reaction was filtered using a vacuum filter, washed three times with deionized water and anhydrous ethanol, and placed in an oven at 60 °C for 12 h, and then placed in a muffle furnace at 800 °C for 2 h to obtain fluorine-nitrogen co-doped zinc oxide.

[0041] Example 5

[0042] Weigh 6.0 g NaOH with an analytical balance and dissolve it in 150 mL deionized water, then weigh 0.11 g NH4F, 0.72 CH4N2O, and 2.23 g Zn(NO3)2 6H2O and dissolve them in 150 mL deionized water. After stirring at 50 °C for 30 min, add the zinc nitrate solution containing ammonium fluoride and urea to the continuously stirred concentrated sodium hydroxide solution at a rate of 30 mL / s, and use a magnetic stirrer to react the solution at 25 °C for 2 h, with a magnetic stirring speed of 500 rpm. The initial product obtained by the reaction was filtered using a vacuum filter, washed three times with deionized water and anhydrous ethanol, and then placed in an oven at 60 °C for 12 h, and then placed in a muffle furnace at 600 °C for 2 h to obtain fluorine-nitrogen co-doped zinc oxide.

[0043] In order to prove that the present invention has excellent photocatalytic antibacterial effect, the photocatalytic antibacterial performance test was carried out on the above examples 1, 2, 3, 4, and 5.

[0044] The specific experiment is:

[0045] like Figure 5-7 As shown, the fluorine-nitrogen co-doped zinc oxide prepared in Example 1-5 was tested for the antibacterial rate of F, N-ZnO against Streptococcus mutans under blue light using the gradient dilution method. 1 mL of BHI liquid culture medium was added to a 48-well plate, and the sterilized F, N-ZnO samples were placed separately, and 10 μ of Streptococcus mutans suspension with OD=0.5 was added. After irradiation with the blue light of a dental curing lamp used clinically for 2 min, the bacterial solution was diluted 10 times to an appropriate concentration, and 500 μ was added to the culture dish, and then 40-50 degrees Celsius agar culture medium was added and shaken. After cooling, it was placed upside down in a 37°C constant temperature incubator for 18-24 hours, and the colonies were counted to calculate the antibacterial rate; Figure 4 is the antibacterial rate of the control group (silicon dioxide), Figure 5-9 They are the antibacterial rates of Examples 1-5 respectively; Table 1 is the antibacterial activity test results of the fluorine-nitrogen co-doped zinc oxide antibacterial agents prepared in Examples 1-5.

[0046] Table 1 Antibacterial rate of fluorine-nitrogen co-doped zinc oxide antibacterial agent in Examples 1-5

[0047] Group Antibacterial rate (no light) Antibacterial rate (blue light) Control group 0 0 Example 1 89.64 99.99 Implementation rate 2 85.47 85.14 Example 3 86.36 87.58 Example 4 59.68 57.15 Example 5 46.68 48.57

Claims

1. A method for preparing a blue light responsive photocatalytic antibacterial agent by using fluorine and nitrogen co-doped zinc oxide, characterized in that: The preparation method of fluorine-nitrogen co-doped zinc oxide comprises the following steps: Step 1, adding a zinc nitrate hexahydrate solution containing ammonium fluoride and urea into a concentrated sodium hydroxide solution, and stirring to obtain a precursor solution; Step 1 is as follows: At 20-25° C., a hexahydrate zinc nitrate solution containing ammonium fluoride and urea is added to a continuously stirred sodium hydroxide solution, and then the reaction is continued at 75-80° C. at a stirring speed of 500-600 rpm for 2-2.5 hours to obtain a precursor solution; wherein the molar ratios of the hexahydrate zinc nitrate solution to the sodium hydroxide, ammonium fluoride, and urea are 1:8-1:11, 1:1-1:1.2, and 1:1-1:3, respectively; Step 2, washing the precursor solution with deionized water and anhydrous ethanol, filtering, and drying in an oven to obtain fluorine-nitrogen co-doped zinc oxide; Step 2 is as follows: The precursor solution obtained by the reaction was washed three times with deionized water using a vacuum filter, and then mixed with the precipitate using ethanol and stirred evenly. After filtering and washing three times, it was placed in an oven at 60-70° C. and dried for 12-15 h to obtain fluorine-nitrogen co-doped zinc oxide.

2. The use of fluorine-nitrogen co-doped zinc oxide for preparing a blue light responsive photocatalytic antibacterial agent according to claim 1, characterized in that: In step 1, zinc nitrate solution is added dropwise to a continuously stirred sodium hydroxide solution at a rate of 15-20 mL / s.

3. A use of fluorine-nitrogen co-doped zinc oxide for preparing a blue light responsive photocatalytic antibacterial agent, characterized in that: The preparation method of fluorine-nitrogen co-doped zinc oxide comprises: 3.0 g NaOH was weighed on an analytical balance and dissolved in 150 mL deionized water. Then 0.22 g NH4F, 0.9 CH4N2O, and 2.23 g Zn(NO3)2 6H2O were weighed and dissolved in 150 mL deionized water. After stirring at 25 °C for 30 min, the zinc nitrate solution containing ammonium fluoride and urea was added to the continuously stirred concentrated sodium hydroxide solution at a rate of 15 mL / s. The solution was reacted at 80 °C for 2 h using a magnetic stirrer, and the speed of the magnetic stirring was 500 rpm. The initial product obtained by the reaction was filtered using a vacuum filter, washed three times with deionized water and anhydrous ethanol, and then placed in an oven at 60 °C for 12 h, and then placed in a muffle furnace at 600 °C for 2 h to obtain fluorine-nitrogen co-doped zinc oxide.

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