Preparation method of piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strip and the prepared tooth strip

Abstract

The present invention discloses a preparation method of a piezoelectric hydrogel-based photocatalytic sterilization whitening tooth paste, comprising the following steps: ultrasonically dispersing a photocatalyst in a mixed solution of dimethyl sulfoxide and deionized water, then adding piezoelectric hydrogel powder, magnetically stirring at 90°C until completely dissolved, to obtain a photocatalytic piezoelectric hydrogel precursor solution; spreading the photocatalytic piezoelectric hydrogel precursor solution on the bottom of a culture dish to obtain a photocatalytic piezoelectric hydrogel precursor film; taking out the photocatalytic piezoelectric hydrogel precursor film together with the culture dish after soaking in deionized water, removing the liquid and freeze-drying to obtain a crude photocatalytic piezoelectric hydrogel film; taking out the crude photocatalytic piezoelectric hydrogel film after soaking in deionized water again, removing the liquid and freeze-drying, repeatedly rinsing with deionized water to remove impurities after multiple repetitions to obtain a photocatalytic piezoelectric hydrogel film; cutting the photocatalytic piezoelectric hydrogel film into pieces with a cutter to obtain a tooth paste. The tooth paste of the present invention has the advantages of whitening teeth and cleaning oral cavity.

Description

Technical Field

[0001] The invention relates to a method for preparing a piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth paste and the prepared tooth paste. Background Art

[0002] With rapid economic and social development and rising living standards, more and more people are becoming more concerned about their appearance and image. White teeth are considered a prerequisite and essential condition for a confident smile. In China, 48% of adults experience varying degrees of tooth discoloration, and 52.6% of these individuals are dissatisfied with their tooth color. Consequently, the development and application of tooth whitening technology has become a key development direction in the medical aesthetics industry. Currently, widely used tooth whitening technologies primarily rely on the bleaching effect of strong oxidizing agents, such as hydrogen peroxide and carbamide peroxide. While these technologies offer some whitening benefits, the use of strong oxidizing agents can cause irreversible damage to teeth and even negatively impact human health. Furthermore, most currently developed tooth whitening technologies and products require professional medical personnel to perform the procedure in a hospital, which is extremely inconvenient. Therefore, there is an urgent need to develop safe, effective, and environmentally friendly tooth whitening technologies to address these issues.

[0003] With advances in nanomaterial preparation and characterization, the application of photocatalysis in human self-cleaning and epidermal immunology has gradually entered the field of human research, becoming a new field and new direction. Furthermore, the study and application of the mechanism of piezoelectric enhancement of photocatalytic performance has become a research hotspot in the field of photocatalysis, focusing on the regulation of photocatalytic efficiency.

[0004] Piezoelectric hydrogels are hydrophilic, three-dimensional mesh structures with excellent mechanical properties. They also possess excellent biocompatibility, toughness, and stable piezoelectric output, promising promising applications in wound therapy and other medical fields. However, their composite application with photocatalysts has not yet been reported.

[0005] Therefore, there is an urgent need to design and develop a new type of piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strip. Summary of the Invention

[0006] In order to solve the above-mentioned problem of lack of safety and convenience in teeth whitening, the present invention provides a method for preparing a piezoelectric hydrogel-based photocatalytic sterilization whitening tooth patch and the prepared tooth patch. The technical solution of the present invention is as follows.

[0007] A method for preparing a piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strip comprises the following steps:

[0008] (1) Ultrasonic dispersion of the pre-prepared photocatalyst in a mixture of dimethyl sulfoxide and deionized water to obtain a photocatalyst dispersion, followed by addition of piezoelectric hydrogel powder to the photocatalyst dispersion, and magnetic stirring at 90°C until completely dissolved to obtain a photocatalytic-piezoelectric hydrogel precursor solution;

[0009] (2) evenly spreading the photocatalytic-piezoelectric hydrogel precursor liquid obtained in step (1) on the bottom of the culture dish to obtain a photocatalytic-piezoelectric hydrogel precursor liquid film;

[0010] (3) Soaking the photocatalytic-piezoelectric hydrogel precursor film obtained in step (2) together with the culture dish in deionized water for 8-12 hours, taking it out, removing the liquid, and freeze-drying it to obtain a crude photocatalytic-piezoelectric hydrogel film;

[0011] (4) placing the crude photocatalytic-piezoelectric hydrogel film obtained in step (3) back into a culture dish and soaking it in deionized water for 8-12 hours, then taking it out, removing the liquid, and freeze-drying it; repeating this process 2-7 times, and then repeatedly rinsing it with deionized water to remove impurities, thereby obtaining a photocatalytic-piezoelectric hydrogel film;

[0012] (5) Using a cutter, the photocatalytic-piezoelectric hydrogel film obtained in step (4) is cut into sheets to obtain a piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strip.

[0013] In order to make the prepared piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strip have excellent photocatalytic effect, the mass ratio of dimethyl sulfoxide to deionized water in step (1) is 15:1-5:1, and the mass ratio of photocatalyst to mixed liquid is 1:10-1:20; in order to make the prepared piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strip have excellent biocompatibility, the mass ratio of piezoelectric hydrogel powder to mixed liquid is 1:8-1:15, and the piezoelectric hydrogel powder is a mixed powder of polyvinyl alcohol powder and polyvinylidene fluoride powder, and the mass ratio of polyvinyl alcohol powder to polyvinylidene fluoride powder is 2:1-5:1.

[0014] In order to make the prepared piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strip have excellent piezoelectricity, the above-mentioned polyvinylidene fluoride powder is any one of polyvinylidene fluoride powder, polyvinylidene fluoride-trichloroethylene powder, and polyvinylidene fluoride-hexafluoropropylene powder.

[0015] In order to make the prepared piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strip have excellent photocatalytic effect, the photocatalyst in step (1) is any one of biocompatible carbon nitride, zinc oxide, and bismuth vanadate.

[0016] In order to obtain a uniform precursor solution, the ultrasonic oscillation time in step (1) is 20 minutes, the magnetic stirring speed is 400-800 r / min, and the stirring time is 2-3 hours.

[0017] In order to make the prepared piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strip have excellent mechanical properties and light absorption properties, the volume of the photocatalytic-piezoelectric hydrogel precursor solution spread into the culture dish in step (2) is 5-10 mL, and the specification of the culture dish is 60 mm.

[0018] In order to effectively prepare the piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strip, the volume of deionized water used for soaking in steps (3) and (4) is 80-300 mL, the freezing temperature is -4°C to -24°C, and the freezing time is 12-24 hours.

[0019] In order to conveniently cut out the piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strips, the cutter in step (5) is a rectangular hard sheet. A first scale bar is set on one surface of the sheet from one side to the other along the length direction. The length of the first scale bar is 7-10 cm. A second scale bar is set on the other opposite surface of the sheet from one side to the other along the width direction. The length of the second scale bar is 0.6-1 cm. The minimum scale unit of the first scale bar and the second scale bar is 1 mm.

[0020] In order to make the cutter lighter and cutting more convenient, the length of the sheet is 10 cm, and the two ends are aligned with the two ends of the first scale bar. The width of the sheet is 1 cm, and the two ends are aligned with the two ends of the second scale bar. The second scale bar is located at the end of the sheet; the end of the sheet where the second scale bar is located is thinned to form a blade.

[0021] The present invention also provides a piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth paste, which is prepared using the above-mentioned method for preparing the piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth paste.

[0022] Beneficial effects: The present invention effectively compounds a semiconductor photocatalyst with a piezoelectric hydrogel, and designs the structure of the composite material into a thin film type loaded with a photocatalyst. The tooth strip thus prepared can generate efficiently separated photogenerated electron-hole pairs under visible light and ultrasonic excitation, and generate active particles that undergo redox reactions with dye molecules on the tooth surface. It can whiten teeth stained by coffee, grape juice, and blueberry juice, respectively, with good whitening effects. Moreover, the tooth strip material has high biocompatibility, which can significantly improve the safety and convenience of tooth whitening. In addition, the piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strip obtained by the present invention unexpectedly has the effect of effectively inactivating the common oral pathogenic bacteria Escherichia coli, and has excellent bactericidal performance, thereby achieving the effect of cleaning the oral cavity. It is of great significance in both basic research on photocatalysis and medical clinical applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a photo of the piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strip (polyvinyl alcohol / polyvinylidene fluoride / carbon nitride) prepared in Example 1 of the present invention;

[0024] Figure 2 This is a photograph of the photocatalytic-piezoelectric hydrogel film obtained in Example 1 of the present invention;

[0025] Figure 3 This is a photo of the piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strip (polyvinyl alcohol / polyvinylidene fluoride / carbon nitride) prepared in Example 1 of the present invention catalytically whitening coffee-stained teeth; a is a photo before whitening; b is a photo after whitening;

[0026] Figure 4 This is a photo of the piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strip (polyvinyl alcohol / polyvinylidene fluoride-trichloroethylene / carbon nitride) prepared in Example 2 of the present invention catalyzing the whitening of grape juice-stained teeth; a is a photo before whitening; b is a photo after whitening;

[0027] Figure 5 This is a photo of the piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strip (polyvinyl alcohol / polyvinylidene fluoride-hexafluoropropylene / carbon nitride) prepared in Example 3 of the present invention catalyzing the whitening of blueberry juice-stained teeth; a is a photo before whitening; b is a photo after whitening;

[0028] Figure 6 This is a diagram showing the effect of the piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strip (polyvinyl alcohol / polyvinylidene fluoride / carbon nitride) prepared in Example 1 of the present invention on catalytic inactivation of Escherichia coli within 1 hour; a is a blank control photo; b is a photo after inactivation of Escherichia coli;

[0029] Figure 7 This is a diagram showing the effect of the piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strip (polyvinyl alcohol / polyvinylidene fluoride / bismuth vanadate) prepared in Example 4 of the present invention on catalytically inactivating Escherichia coli within 2 hours; a is a blank control photo; b is a photo after inactivation of Escherichia coli;

[0030] Figure 8 Schematic diagram of the structure of the cutter in the present invention; a is a diagram of one side of the cutter with a first scale bar; b is a diagram of the other side of the cutter with a second scale bar; c is a side view of the cutter with a blade. DETAILED DESCRIPTION

[0031] The technical solutions of the present invention are described in detail below through examples, but the protection scope of the present invention is not limited to the examples. Example 1

[0032] A piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strip (polyvinyl alcohol / polyvinylidene fluoride / carbon nitride) is prepared by a method comprising the following steps. All raw materials used below, except for some that were homemade, are commercially available.

[0033] S1: Add 500 mg of pre-synthesized photocatalyst carbon nitride (g-C3N4) to a mixture of 9 g of dimethyl sulfoxide and 1 g of deionized water and ultrasonically disperse it for 20 minutes to form a carbon nitride dispersion; disperse 700 mg of polyvinyl alcohol powder (weight average molecular weight 146,000, Aladdin Reagent (Shanghai) Co., Ltd.) and 300 mg of polyvinylidene fluoride powder (number average molecular weight 543,000, Sigma-Aldrich (Shanghai) Trading Co., Ltd.) in the above carbon nitride dispersion, and magnetically stir at 90°C and a stirring speed of 600 r / min for 3 hours until the polyvinyl alcohol powder and polyvinylidene fluoride powder are completely dissolved to obtain a photocatalytic-piezoelectric hydrogel precursor.

[0034] The above carbon nitride (g-C3N4) is prepared by the following steps:

[0035] S1.1 Weigh 20 g of urea in a mortar, grind thoroughly, and transfer to a corundum crucible;

[0036] S1.2 Place the corundum crucible in a muffle furnace for sintering. Heat the reactants to 520°C at a rate of 20°C / min and hold for 2 hours.

[0037] S1.3 Cool the muffle furnace and the product inside to room temperature at a rate of 20°C / min to obtain a light yellow powder, which is g-C3N4.

[0038] S2: Use a pipette to transfer 8 mL of the above-mentioned photocatalytic-piezoelectric hydrogel precursor solution into a culture dish with a diameter of 60 mm to form a uniform photocatalytic-piezoelectric hydrogel precursor solution film on the bottom.

[0039] S3: The photocatalytic-piezoelectric hydrogel precursor liquid film and the culture dish were placed in 200 mL of deionized water and soaked for 10 hours, then taken out, and after removing the liquid, freeze-dried at -20°C for 18 hours using a freeze dryer to obtain a crude photocatalytic-piezoelectric hydrogel film.

[0040] S4: The crude photocatalytic-piezoelectric hydrogel film was placed in a culture dish again and soaked in 200 mL of deionized water for 10 h. After removal, the film was freeze-dried at -20 °C for 18 h using a freeze dryer. This process was repeated 7 times, and then the film was rinsed repeatedly with deionized water to remove impurities. A photocatalytic-piezoelectric hydrogel film with a thickness of 1 mm (such as Figure 2 shown).

[0041] S5: Use a cutter to cut the photocatalytic-piezoelectric hydrogel film in step (4) into 0.5 cm*1 cm pieces to obtain a piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strip (polyvinyl alcohol / polyvinylidene fluoride / carbon nitride).

[0042] The above-mentioned cutting knife Figure 8As shown, there is a rectangular stainless steel sheet 1 with a length of 10 cm, a width of 1 cm and a thickness of 1 mm. A first scale bar 11 is engraved on one surface of the sheet 1 from one side to the other along the length direction. The length of the first scale bar 11 is 10 cm, and the two ends of the sheet 1 in the length direction are aligned with the two ends of the first scale bar 11; a second scale bar 12 is engraved on the other opposite surface of the sheet 1 from one side to the other along the width direction. The length of the second scale bar 12 is 1 cm, and the two ends of the sheet 1 in the width direction are aligned with the two ends of the second scale bar 12, and the second scale bar 12 is located at the end of the sheet 1; the end of the sheet 1 where the second scale bar 12 is located is thinned to form a blade 13; the minimum scale units of the above-mentioned first scale bar 11 and second scale bar 12 are both 1 mm.

[0043] When cutting, first use the cutting blade 13 to cut a section of the photocatalytic-piezoelectric hydrogel film, then use the second scale bar 12 at one end of the cutting blade to measure the width of the tooth paste, and then press the cutting blade 13 to cut a first incision perpendicular to the section, and then use the first scale bar 11 or the second scale bar 12 to measure the length of the tooth paste, and then cut a second incision perpendicular to the section and with the same depth as the first incision, and then use the cutting blade 13 to cut so that the bottoms of the two incisions are connected, that is, a rectangular tooth paste is cut.

[0044] The piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strip (polyvinyl alcohol / polyvinylidene fluoride / carbon nitride) obtained by the above preparation method was photographed. The digital photos are as follows: Figure 1 shown. Example 2

[0045] The mass of the photocatalyst carbon nitride in Example 1 was changed to 800 mg, the polyvinylidene fluoride powder was changed to polyvinylidene fluoride-trichloroethylene powder (vinylidene fluoride molar weight 55%, FC45, Arkema China), and the cutting size was changed to 0.5 cm*0.7 cm. Except for this, a piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strip (polyvinyl alcohol / polyvinylidene fluoride-trichloroethylene / carbon nitride) was prepared in the same manner as Example 1. Example 3

[0046] The polyvinylidene fluoride powder in Example 1 was changed to polyvinylidene fluoride-hexafluoropropylene powder (weight average molecular weight 445,000, number average molecular weight 110,000, Sigma-Aldrich (Shanghai) Trading Co., Ltd.), and the cutting size was changed to 0.5 cm*0.5 cm. Otherwise, a piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strip (polyvinyl alcohol / polyvinylidene fluoride-hexafluoropropylene / carbon nitride) was prepared in the same manner as in Example 1.

[0047] Piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strips for teeth whitening

[0048] In order to verify and evaluate the actual teeth whitening effect of the prepared piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strips, the piezoelectric electric field enhanced photocatalytic teeth whitening process was simulated in the laboratory.

[0049] S1: First, the ex vivo teeth were bleached to eliminate the influence of the stains on the teeth in the early stage on the experiment.

[0050] The teeth bleaching process is as follows:

[0051] S1.1 Rinse the excised tooth repeatedly with deionized water to remove surface residues;

[0052] S1.2 Place the teeth in a 30% concentration hydrogen peroxide solution and ultrasonically clean them for 5 minutes. Repeat this process three times until the tooth surface is completely bleached.

[0053] S2: Staining of bleached teeth.

[0054] Coffee, grape juice, and blueberry juice, which contain dye molecules and are commonly consumed in daily life, were selected as tooth dyes. The specific tooth dyeing process is as follows:

[0055] S2.1 Place the bleached teeth in 20 mL of coffee, grape juice, or blueberry juice and soak them at room temperature for 5 days until obvious staining appears on the teeth.

[0056] S2.2 Remove the stained teeth, dry them, and take photos to compare the teeth whitening effect.

[0057] S3: Photocatalytic teeth whitening test.

[0058] S3.1 First, the piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strip (polyvinyl alcohol / polyvinylidene fluoride / carbon nitride) obtained in Example 1, the piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strip (polyvinyl alcohol / polyvinylidene fluoride-trichloroethylene / carbon nitride) obtained in Example 2, and the piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strip (polyvinyl alcohol / polyvinylidene fluoride-hexafluoropropylene / carbon nitride) obtained in Example 3 were respectively adhered to teeth stained with coffee, grape juice, or blueberry juice. The strips were then placed in a reactor, and 20 mL of deionized water was added to each of the reactors, ensuring that the piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strips and the stained teeth were completely submerged in the deionized water.

[0059] S3.2 Then, turn on the power density to 0.2W / cm 2 The distance between the light source and the reactor was 10 cm, the cooling water temperature was set to 35 ° C, and the illumination was continuous for 2 h under ultrasonic oscillation;

[0060] S3.3 Remove the tooth, dry it, and take a photo for comparison.

[0061] The piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strips prepared in Examples 1, 2, and 3 have the following effects on catalytic whitening of teeth stained by coffee, grape juice, and blueberry juice: Figure 3 、 Figure 4 and Figure 5 shown.

[0062] Experimental study on bacterial inactivation of piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strips

[0063] During the photocatalytic sterilization process, the power density used was 0.2W / cm 2 A xenon lamp was used as the light source, the distance from the light source to the reactor was 10 cm, and the cooling water temperature was set to 25°C. Six piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strips (polyvinyl alcohol / polyvinylidene fluoride / carbon nitride) obtained in Example 1 were taken and placed in a 35 mm culture dish. 4 mL of a 1*10 6 CFUmL -1 coli on the piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strip. Subsequently, the light source was turned on to catalyze the reaction for 1 hour. Finally, the number of live Escherichia coli was counted by the plate counting method. For comparison, the piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strip was not used, and the blank control experiment was carried out according to the above steps. The results show that the piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strip (polyvinyl alcohol / polyvinylidene fluoride / carbon nitride) of Example 1 can effectively inactivate the common pathogenic bacteria Escherichia coli in the oral cavity within 1 hour with an efficiency of 74.9%. The results are as follows Figure 6 shown. Example 4

[0064] A piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strip (polyvinyl alcohol / polyvinylidene fluoride / bismuth vanadate) was prepared in the same manner as in Example 1, except that the photocatalyst in Example 1 was changed to 1 g of bismuth vanadate.

[0065] Bismuth vanadate is prepared by the following steps:

[0066] S1: Weigh 1 mmol of Bi(NO3)3.5H2O and 1 mmol of H4NO3V, respectively, and stir them magnetically at 400 rpm for 30 min until they are completely dissolved in 60 mL of deionized water;

[0067] S2: Add 0.3 mol HNO3 dropwise to the precursor solution obtained in step S1 above, and stir magnetically at a stirring speed of 400 r / min for 2 h;

[0068] S3: The precursor solution obtained in step S2 was transferred to a 100 mL reactor and reacted at 180°C for 12 h. After the reactor was cooled to room temperature, the reaction product was washed with deionized water and anhydrous ethanol, and centrifuged at 10,000 rpm for 5 times.

[0069] S4: The centrifuged product obtained in the above step S3 was placed in a 60°C forced air oven and dried overnight.

[0070] The same bacterial inactivation test was conducted using the piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strip (polyvinyl alcohol / polyvinylidene fluoride / bismuth vanadate) of Example 4. The results showed that it had a similar sterilization effect to the piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strip (polyvinyl alcohol / polyvinylidene fluoride / carbon nitride) prepared in Example 1. Figure 7 shown.

[0071] The technologies not specifically mentioned above are all referenced to the existing technologies.

[0072] As described above, although the present invention has been shown and described with reference to specific preferred embodiments, it should not be construed as limiting the present invention itself. Various changes may be made to it in form and detail without departing from the spirit and scope of the present invention as defined in the appended claims.

Claims

1. A method for preparing a piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strip, characterized in that: The steps include: (1) Ultrasonic dispersion of the pre-prepared photocatalyst in a mixture of dimethyl sulfoxide and deionized water to obtain a photocatalyst dispersion, followed by addition of piezoelectric hydrogel powder to the photocatalyst dispersion, and magnetic stirring at 90°C until completely dissolved to obtain a photocatalytic-piezoelectric hydrogel precursor solution; (2) evenly spreading the photocatalytic-piezoelectric hydrogel precursor liquid obtained in step (1) on the bottom of the culture dish to obtain a photocatalytic-piezoelectric hydrogel precursor liquid film; (3) Soaking the photocatalytic-piezoelectric hydrogel precursor film obtained in step (2) together with the culture dish in deionized water for 8-12 hours, taking it out, removing the liquid, and freeze-drying it to obtain a crude photocatalytic-piezoelectric hydrogel film; (4) placing the crude photocatalytic-piezoelectric hydrogel film obtained in step (3) back into a culture dish and soaking it in deionized water for 8-12 hours, then taking it out, removing the liquid, and freeze-drying it; repeating this process 2-7 times, and then repeatedly rinsing it with deionized water to remove impurities, thereby obtaining a photocatalytic-piezoelectric hydrogel film; (5) Using a cutter, the photocatalytic-piezoelectric hydrogel film obtained in step (4) is cut into sheets to obtain a piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth paste; The mass ratio of dimethyl sulfoxide to deionized water in step (1) is 15:1-5:1, and the mass ratio of the photocatalyst to the mixed solution is 1:10-1:20; the mass ratio of the piezoelectric hydrogel powder to the mixed solution is 1:8-1:15, and the piezoelectric hydrogel powder is a mixed powder of polyvinyl alcohol powder and polyvinylidene fluoride powder, and the mass ratio of the polyvinyl alcohol powder to the polyvinylidene fluoride powder is 2:1-5:1; The polyvinylidene fluoride powder is any one of polyvinylidene fluoride powder, polyvinylidene fluoride-trichloroethylene powder, and polyvinylidene fluoride-hexafluoropropylene powder; The photocatalyst in step (1) is any one of carbon nitride, zinc oxide, and bismuth vanadate that are biocompatible.

2. The preparation method of the piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth paste according to claim 1, characterized in that: The ultrasonic oscillation time in step (1) is 20 minutes, the magnetic stirring speed is 400-800 r / min, and the stirring time is 2-3 hours.

3. The preparation method of the piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth paste according to claim 1, characterized in that: The volume of the photocatalytic-piezoelectric hydrogel precursor solution spread into the culture dish in step (2) is 5-10 mL, and the size of the culture dish is 60 mm.

4. The method for preparing the piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strip according to claim 1, characterized in that: The volume of deionized water used for soaking in steps (3) and (4) is 80-300 mL, the freezing temperature is -4°C to -24°C, and the freezing time is 12-24 hours.

5. The method for preparing the piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strip according to claim 1, characterized in that: The cutter in step (5) is a rectangular hard sheet. A first scale bar is provided on one surface of the sheet from one side to the other along the length direction. The length of the first scale bar is 7-10 cm. A second scale bar is provided on the other opposite surface of the sheet from one side to the other along the width direction. The length of the second scale bar is 0.6-1 cm. The minimum scale unit of the first scale bar and the second scale bar is 1 mm.

6. The method for preparing the piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strip according to claim 5, characterized in that: The length of the sheet is 10 cm, and its two ends are aligned with the two ends of the first scale bar. The width of the sheet is 1 cm, and its two ends are aligned with the two ends of the second scale bar. The second scale bar is located at the end of the sheet. The end of the sheet where the second scale bar is located is thinned to form a blade.

7. A piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth strip, characterized in that: The invention is prepared by the preparation method of the piezoelectric hydrogel-based photocatalytic sterilization and whitening tooth paste according to any one of claims 1 to 6.

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